Inflammatory mechanisms are increasingly recognized as important contributors to the pathogenesis of neurodegenerative diseases, including Lewy body dementia (LBD). Our objectives were to, firstly, review inflammation investigation methods in LBD (dementia with Lewy bodies and Parkinson’s disease dementia) and, secondly, identify alterations in inflammatory signals in LBD compared to people without neurodegenerative disease and other neurodegenerative diseases. A systematic scoping review was performed by searching major electronic databases  to identify relevant human studies. Of the 2509 results screened, 80 studies were included. Thirty-six studies analyzed postmortem brain tissue, and 44 investigated living subjects with cerebrospinal fluid, blood, and/or brain imaging assessments. Largely cross-sectional data were available, although two longitudinal clinical studies investigated prodromal Lewy body disease. Investigations were focused on inflammatory immune cell activity  and inflammatory molecules . Results of the included studies identified innate and adaptive immune system contributions to inflammation associated with Lewy body pathology and clinical disease features. Different signals in early and late-stage disease, with possible late immune senescence and dystrophic glial cell populations, were identified. The strength of these associations is limited by the varying methodologies, small study sizes, and cross-sectional nature of the data. Longitudinal studies investigating associations with clinical and other biomarker outcomes are needed to improve understanding of inflammatory activity over the course of LBD. This could identify markers of disease activity and support therapeutic development. Lewy body dementia (LBD), the second-commonest neurodegenerative dementia after Alzheimer’s disease (AD), is characterized neuropathologically by abnormal α-synuclein aggregates (Lewy bodies and Lewy neurites) in the brain and clinically by progressive cognitive and motor impairment that leads to functional disability. Accurate diagnosis remains difficult, especially in early disease stages, due to the highly variable clinical course and lack of specific diagnostic tests .LBD encompasses dementia with Lewy bodies (DLB) and Parkinson’s disease dementia (PDD), two syndromes with significant clinical and neuropathological overlap. They are distinguished by the timing of dementia onset related to motor Parkinsonism, which occurs within 12 months for DLB or greater than 12 months in PDD . While nThe prodromal, or ‘pre-dementia’, stage of LBD is now an area of increased research focus towards understanding early disease mechanisms. Mild Cognitive Impairment (MCI) describes cognitive decline before significant loss of ability to perform usual social and occupational functions occurs, which is a defining feature of dementia. Specific research criteria for prodromal DLB have recently been proposed, including an operationalized definition of MCI associated with Lewy body pathology (MCI-LB) .Despite advances in understanding of hallmark neuropathology and clinical disease stages and important learnings from related conditions, including PD and AD, key challenges remain. These include understanding the link between α-synuclein and pathogenic mechanisms of disease initiation and progression to dementia, establishing disease-specific biomarkers that relate to clinical outcomes, and identifying targets for still-elusive disease-modifying therapy. The potentially central role of inflammatory pathways in dementia pathogenesis, and therefore the measurement of inflammatory molecules as markers of disease activity, is one avenue of exploration towards addressing these challenges . MountinEvidence from in vitro or animal disease models, direct examination of human postmortem brain parenchyma, and in vivo biofluid or imaging studies suggests an important relationship between α-synuclein, inflammation, and LBD pathogenesis ,11. AdvaComponents of the central nervous system (CNS) important in neurodegenerative disease inflammatory signals include resident glial cells—microglia and astrocytes (astroglia) . MicroglAstrocytes also have a central role in brain homeostasis, including contributions to inflammatory responses, and have been implicated in several neurodegenerative diseases . The impAdaptive immune cell populations, such as T and B lymphocytes, are often closely linked with innate immune system activity, particularly in chronic inflammatory states where they can be involved in perpetuating inflammatory responses. Lymphocytes respond to glial cell release of inflammatory molecules and antigen presentation functions, which trigger activation and trafficking from the periphery into the CNS . T lymphCytokines and chemokines, inflammatory signaling molecules, can also be measured across a range of biological tissues. Pro-inflammatory molecules include interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-8, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, and monocyte chemoattractant protein-1 (MCP-1). IL-10 and TGF-β are associated with a more regulatory or anti-inflammatory environment. Improved understanding of these signals in neurodegenerative disease has been facilitated by advances in biomarker assay technology, such as electroluminescence-based multiplex assays and the single molecule array (Simoa), which allow accurate measurement of molecules in ultra-low concentrations in biofluid (CSF and blood) . In PD, Other signals for altered inflammatory mechanisms in neurodegenerative disease and α-synucleinopathy come from studies of genes and gene expression, including transcriptomics. A mutation in TREM2 (which encodes triggering receptors expressed on myeloid cell 2 (TREM2), expressed by brain microglia, and involved in determining inflammatory phenotype) is a risk factor for PD as well as AD and frontotemporal dementia . In a prConsidering the substantial interest in recent years regarding inflammation in LBD and the new in vivo opportunities brought by advances in research tools, we aimed to synthesize the current literature in this scoping review. A systematic scoping review methodology was selected to provide a comprehensive synthesis of this heterogeneous research field that is characterized by varying approaches and definitions in order to identify key themes and areas for future research .Review the methods used to investigate inflammation in LBD and how these are applied to conceptualize inflammation.Primary objective:Identify alterations in inflammation signals in LBD compared to people without neurodegenerative disease and compared to related neurodegenerative diseases, in particular AD and PD.Secondary objective:This review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines  30], us, us30], A systematic search strategy was applied to identify relevant publications.Original peer-reviewed research study.People with clinically diagnosed dementia with Lewy bodies (DLB), Parkinson’s disease dementia (PDD), or Lewy body dementia (LBD) without specification of DLB or PDD. For postmortem studies, the use of international neuropathological criteria for diagnosis was sufficient.Inflammation is assessed either postmortem or in vivo.Inclusion criteria:Studies where LBD participants have a comorbid inflammatory condition that might impact the assessment of inflammation, e.g., encephalitis, multiple sclerosis, inflammatory arthritis, or sepsis.People with a Lewy body disease  without dementia, including people with mild cognitive impairment (MCI).In interventional studies, assessments of inflammation are taken while receiving or after the intervention.Non-English language.Exclusion criteria:A systematic search was performed using the electronic bibliographic databases MEDLINE, EMBASE, PsycINFO, and Web of Science. No restrictions were placed on the search. Reference lists of eligible studies and review articles were also screened. 1.(Lewy.mp AND dementia) OR dementia with lewy bodies.mp OR ((Parkinson Disease/OR parkinson’s disease.mp) AND dementia.mp) OR Parkinson’s disease dementia.mpThe following search terms were used:2.inflammat* OR neuroinflammat* OR Neurogenic inflammation/OR microglia.mpANDAn example search strategy is provided in The final search was conducted on 26 January 2023. Search results were imported into the Covidence online review management system, which was also used for charting data from included studies into standardized data collection forms. Two authors (PML and JJY) independently screened titles and abstracts to select studies for full-text review. The authors were initially blinded to each other’s decisions, and then any disagreements were discussed. If consensus was not reached, the study was included for full-text review. The full text review was performed independently by the same two authors, initially blind to each other’s decisions. If an agreement was not reached through discussion between the two authors, the studies were discussed with two senior authors .When multiple analyses or publications relating to a single research study cohort were identified, these were, where possible, combined for extraction with the aim that participant numbers were not counted more than once. If validation cohorts were reported, these were only included for data extraction if baseline cohort demographics were provided and all inclusion criteria were met.After duplicates were removed, 2509 search results were screened, and 306 studies underwent full text review . Eighty Inflammation and LBD were investigated using postmortem brain tissue (36 studies), fluid or imaging biomarkers measured in living subjects (44 studies), and analysis of genetic factors (3 studies) . Most stAll included studies provided cross-sectional data for participants with LBD, although two studies reported longitudinal data relating to participants with prodromal LBD ,32 and oIncluded studies report cohorts from Europe , Asia (12 studies), North America (19 studies), South America (1 study), and Australia (1 study), of which six studies included participants from multiple regions a. ParticSignals of altered inflammatory mechanisms in LBD appeared to be variable across the disease timeline . In prodThe understanding of the role of microglia in LBD disease mechanisms has evolved with the application of new analytical techniques and the re-interrogation of previous conclusions. Analysis of LBD brain tissue by McGeer et al. provided the earliest reports associating microglia with hallmark neuropathology . The hypPotential stimuli for LBD-associated glial cell activation identified at postmortem include the complement pathway ,38,41, iThree decades after the publication of McGeer et al., several groups also used microglial morphological assessment to argue against the initial proposition that microglial activation is a hallmark of LBD neuropathology. Classification of activated microglia by visual confirmation of an ameboid state and increased staining of activation markers, such as CD68, found no increase in activated microglia in LBD brains and, interestingly, the presence of greater numbers of dystrophic microglia compared to age-matched controls ,45,46,47Understanding microglial contribution to LBD has recently been progressed by in vivo PET imaging studies using the [11C]PK11195 ligand against the TSPO microglial marker, albeit in only a few small studies . Several studies show an association between LBD pathology and increased microglial activity compared to controls on TSPO PET imaging ,50,51,52The markers GFAP and YKL-40 have been used to identify astrocytes in LBD brain tissue and test the hypothesis of a pathological contribution to disease processes, which likely include inflammatory mechanisms based on known functions, including interactions with activated microglia . IncreasIn living subjects with LBD, evaluation of astrocytes is limited to biofluid due to a lack of suitable imaging ligands. YLK-40 measured in CSF and blood has been presented as a marker of inflammation, often associated with astrocyte activity, in several LBD cohorts ,65,66,67Regarding GFAP, measurement in CSF or blood has been applied in a few recent LBD cohorts; however, it has largely been considered a marker of general neurodegeneration and not linked to inflammatory mechanisms or astrocytes specifically, and therefore was not identified in the systematic search for this review. One study included in this review measured GFAP in biofluid along with other inflammatory markers in CSF and found that GFAP levels did not correlate with YKL-40 across diagnostic groups, including DLB . T lymphocyte involvement, and particularly the CD4+ helper T cell subset, has been identified by a few small studies of advanced LBD. In postmortem DLB and PDD brains, increased recruitment of CD3+ or CD3+/4+ T lymphocytes has been observed compared to controls across multiple brain regions, including in association with glial cells and α-synucleinopathy ,69,70,71In living cohorts, altered adaptive immune system activity in LBD was suggested by two studies, which found reduced activation of CD4+ T and B lymphocyte subsets in blood compared to controls and AD groups, with one also reporting a non-significant trend towards increased CD8+ cytotoxic T lymphocytes in DLB compared to controls and AD ,73. The In this review, several studies measured cytokines or other inflammatory mediators in postmortem or in vivo samples. Details of each study and key outcomes are reported in While results are variable, differences between LBD and controls point towards altered inflammatory profiles. Interestingly, discordance between DLB and PDD in postmortem and in vivo studies was also noted. Regarding pro-inflammatory cytokines in DLB, altered TNF-α and IL-6 levels were detected in several cohorts at postmortem ,42,56 anIn blood, several recent studies applied large cytokine panels to look for differences between groups of interest with variable results, including possible associations with clinical outcomes ,72,78,79One cohort assessed blood cytokine profiles over disease stages by comparing pre-dementia DLB  and established DLB . They foVascular endothelial cells can play important roles in inflammatory responses through the expression of inflammatory mediators, including cytokines and chemokines, that recruit circulating innate and adaptive immune system elements to sites of tissue injury. One European DLB cohort investigated in vivo several CSF inflammatory markers implicated in vascular endothelial inflammation, including their relationship with other inflammatory molecules ,85,86,87Concordant with these findings, ICAM-1 expression was higher in the DLB group but not the PDD group compared to controls in a postmortem study, although ICAM-1 did not correlate with visualized Lewy body pathology , and VCAElevated CRP and high-sensitivity CRP (hsCRP) levels in PDD, compared to PD and controls, have been demonstrated in blood and CSF ,90,91,92Another acute-phase clinical marker, procalcitonin, was evaluated in only one included study . In the A range of other inflammation-associated molecules have been assessed in only one or two small studies investigating inflammation in LBD. At postmortem, altered soluble epoxide hydrolase  and cyclIn vivo studies suggest that osteopontin (CSF and blood) ,98, serpAnalysis of RNA expression in serum small extracellular vesicles (SEVs), an emerging technique that allows in vivo analysis of CNS-derived RNA that crosses into peripheral circulation, also provides evidence for altered inflammatory cytokine activity in DLB compared to controls . This stTranscriptome-based approaches for the analysis of postmortem LBD brain tissue also implicated the importance of altered inflammatory pathways and immune senescence at late stages. In DLB compared to controls, DEGs included downregulation of inflammation and immune system gene clusters, including antigen presentation and processing (including MHC II) and the innate immune response activating the cell surface receptor signaling pathway . SimilarOne study of mRNA expression from whole blood collected in vivo found upregulation in TNF-α signaling via the NFκB pathway and the Inflammatory response pathway in DLB  and AD on gene set enrichment analyses . DiffereTwo studies evaluated genetic variants relevant to cytokines in LBD . One stuAnother study looked to validate rare coding variants ABI3_rs616338-T and PLCG2_rs72824905-G that had been identified as important for AD risk and implicated in alterations in neuroimmunity and neuroinflammation for disease pathogenesis . While tFrom early to advanced-stage disease, altered inflammatory signals have been detected in LBD. Previously considered a bystander consequence of neurodegeneration-driven toxicity, studies identified in this systematic scoping review examined inflammation as a potential driver of disease progression and marker of disease activity. Advances in investigation techniques have allowed interrogation of pathogenic inflammatory mechanisms proposed by in vitro and animal models of α-synucleinopathy with human studies ,110. Initiation of innate inflammatory mechanisms through α-synuclein-related glial cell activation and inflammatory cytokine production is one proposed mechanism of neurodegeneration in LBD. In this review, alterations in microglia numbers and pro-inflammatory activity were seen in several studies of postmortem brain tissue or in vivo analysis of biofluid and PET imaging. These findings are supported by pre-clinical studies that show increased α-synuclein translocation into neuronal vesicles in stress states, where it abnormally aggregates and can be released by exocytosis . SolubleLRRK2, a PD-risk gene, have also been linked with increased α-synuclein-related CNS infiltration of pro-inflammatory peripheral monocytes in a mouse model [The variability in microglial profiles over the disease course is an important recent development in the study of LBD pathobiology. In the human studies reviewed, a case can be made for microglial activation in early disease, which may be initially neuroprotective or enhance vulnerability to degeneration, followed by a chronic inflammatory state and subsequent microglial dystrophy and loss of function. PET imaging studies showing reduced microglial activity associated with more advanced disease are congruent with postmortem findings of dystrophic microglia in late-stage disease, which could result from chronic inflammation that has been present for many years at the time of death. While longitudinal human data is required to confirm this pattern of early microglial activity that wanes with disease progression, in a rat model of α-synucleinopathy immunoreactive microglia numbers peaked at 2 months from disease induction in association with Lewy body-like neuronal inclusions, 3 months prior to neurodegenerative changes  . Microglse model .Altered longitudinal inflammatory cytokine profiles identified in prodromal Lewy body disease may also be related to this microglia-related disease mechanism, although microglial-specific markers in blood or CSF have not been identified. An important consideration is that the signature of activated microglia is not unique to LBD. This is also observed in other neurodegenerative dementias at postmortem and on PET, including AD, FTLD, and PSP . TherefoAstrocytes, another glial cell population integral to CNS immune responses and widely investigated in neurodegenerative diseases, were also identified in this review as likely contributing to inflammatory signals in LBD. Questions remain, however, regarding whether astrocytes are key drivers of pathological inflammatory mechanisms of disease in LBD and also whether the currently utilized markers GFAP and YKL-40 accurately detect pro-inflammatory activation states of astrocytes when measured in CSF or blood . GFAP leT lymphocytes, particularly CD4+ helper T cells, may contribute to chronic inflammatory processes in LBD. In human studies and mouse models of α-synucleinopathy, their numbers are increased in parenchyma and perivascular brain regions, and they are located close to astroglial processes in areas of tissue with signs of glial activation and inflammation . Pre-cliThe impact of AD-type co-pathology, hyperphosphorylated tau (p-tau), and amyloid-β may be important in the inflammatory signals detected in clinical LBD studies. The relationship between inflammation and hallmark proteinopathy is much more developed in dementia due to AD ,135, wheWhile DLB and PDD are separate clinical diagnoses distinguished by the somewhat arbitrary assessment of a 12-month gap between motor Parkinsonism and dementia onset for PDD, significant overlap in hallmark neuropathology, genetics, imaging, and clinical features allows classification together under the umbrella of LBD. The debate continues as to whether these are truly distinct diseases or different spectrums of the same entity . This review identifies some discordant signals in inflammatory profiles between DLB and PDD from different cohorts; however, varying methodologies between studies and a lack of direct comparison between DLB and PDD groups in all but 12 studies limit the conclusions that can be drawn. Future studies should directly compare DLB and PDD groups to clarify whether these conditions have truly different pathobiological inflammatory profiles and consider whether it is appropriate to combine PDD and DLB groups in future studies of LBD. Cohort studies of PD should also consider reporting PDD results separately, which will assist in understanding if there is an inflammatory signal specific to dementia development.The hazards of divided research efforts in the investigation of LBD disease should also be considered. This review identified a significant body of work investigating inflammation in DLB or PDD, but most studies report on only one or the other diagnostic group. This is despite pre-clinical disease models, which form the basis of tested hypotheses, being applicable to both DLB and PDD. Given the challenges of performing adequately powered clinical studies in this often frail and multimorbid population of older adults, this is an important consideration. Future research efforts should focus on collaboration between DLB and PDD cohorts globally, using standardized research methods to enable comparison, to give the best chance of meaningful advances in understanding the inflammatory mechanisms of LBD disease pathobiology. The discordance between clinical and neuropathological diagnoses in dementia, particularly LBD, is well documented . A majorRegarding study design, cross-sectional data and small sample sizes limit the conclusions that can be drawn from the studies identified in this review. Participant cohorts were also largely concentrated in Europe and North America; therefore, future research should include more geographically diverse populations that are followed longitudinally. Longitudinal studies including pre-dementia or ‘prodromal’ participants whose subsequent conversion to clinical dementia is not confirmed also must be interpreted with caution. Not all people with prodromal Lewy body disease go on to develop dementia, and therefore they do not all represent a component of the dementia disease spectrum. This is particularly important in the context of increasing research focus on the prodromal stage of neurodegenerative disease as a key target for disease-modifying therapy.Postmortem analysis of LBD brains provides invaluable insights into neuropathology at the tissue level; however, this method usually limits researchers to end-stage disease. Therefore, processes important in early disease development may be absent. While many brain banks now provide the clinical history of donors, the severity of dementia and clinical stage at death are often not available. Given the evidence from in vivo studies of a changing inflammatory signal across LBD disease stages, postmortem studies should endeavor to correlate histopathological data with clinical disease stage at death and compare signals in early and late-stage disease.The anatomical region from which brain tissue was sampled must also be noted when evaluating postmortem studies, given the known regional distributions and variable progression rates of neurodegenerative pathological change in LBD. This was highly varied across the studies identified in this review . Future The assessment of non-specific inflammatory markers in a disease cohort comprised of older adults poses several challenges. This demographic is more likely to have multiple comorbidities that may influence inflammatory signals, particularly those measured peripherally in the blood. The potential impact of comorbid neuropathology, such as cerebrovascular disease or AD-related pathology (amyloid-β and tau), must also be considered, the latter of which is known to be frequently present in DLB ,153. ThiBiological age has also been shown to impact cytokine levels ,76, micrWhile the prospect of reliable biofluid-based markers is enticing given the potential for repeatability, transportability, and ease of collection, particularly associated with blood, additional potential confounders must be considered. Whether or not the molecule of interest crosses the blood-brain barrier and can be reliably measured in blood to reflect CNS pathology must be interrogated. In a few studies that investigated paired CSF and blood samples, no correlation was found between the measurements for several inflammatory molecules , albeit in early studies where assay sensitivity may have been lacking ,155. ThiIt is also important to note that in LBD, there was no difference found for the majority of inflammatory molecules assessed by studies in this review. This may be due to a difference only in a few key inflammatory mediators at various disease stages or the limitations of various assessment techniques and patient factors that may distort the detection of the true relationships. Several relatively recent studies using assays with improved sensitivities were still unable to report on planned biofluid cytokines due to undetectable or unreliable levels  ,156, levVariations in methodologies used to analyze markers of inflammation may impact results. Blood levels of cytokines, and possibly other biomarkers of interest, are affected by diurnal variation . Only a This systematic scoping review describes a range of approaches applied to the assessment of inflammation in LBD across several substrates, most commonly postmortem brain tissue or biofluid collected in vivo, with a few studies utilizing a PET imaging ligand for microglia. Identified studies reveal important insights into inflammatory mechanisms across the LBD disease course that show differences compared to control and other neurodegenerative disease groups. Changes over the course of the disease in LBD may be early pro-inflammatory events relating to innate immune system activation with contributions from microglia, astrocytes, and inflammatory mediators including cytokines and vascular mediators, some of which may be neuroprotective. Helper T lymphocytes may also become involved, linking innate and adaptive immune activation and contributing to chronic inflammation. In advanced stages of LBD, chronic inflammation and immune senescence involve dystrophic microglia and possibly reduced lymphocyte responses. Potential differences between PDD and DLB also require further investigation and replication.Highlighted in this review is the challenge posed by the ubiquitous nature of key inflammatory and immune mechanisms and defining abnormal pathobiology compared to normal homeostatic pathways in neurodegenerative disease. As new molecules have been identified or their functions described in new ways, and the complex links with the immune system and other metabolic functions across human diseases are delineated, the interpretation of experimental results must be reviewed and potentially re-interpreted. This may yield novel approaches to disease detection, prognosis, and monitoring. Whether these inflammatory signals will yield a therapeutic target for disease modification with an acceptable adverse event risk profile, however, remains to be seen. Verification of these hypotheses will require significant additional data from well-characterized cohorts, with longitudinal measurements that correlate multiple inflammatory measurements and neuropathological verification at postmortem or in vivo. Application of ultra-sensitive assays for inflammatory molecules of interest may improve clarity. The impact of comorbid neuropathology, particularly of the AD type, must also be determined. Development of further imaging ligands to assess other CNS inflammatory signals beyond microglia is needed, as is the development of blood-based biomarkers that can be easily repeated over the course of the disease to track disease activity and, potentially, response to disease-modifying therapies in the future.


Heart failure with preserved ejection fraction (HFpEF) is a heterogeneous clinical syndrome with multiple underlying mechanisms and comorbidities that leads to a variety of clinical phenotypes. The identification and characterization of these phenotypes are essential for better understanding the precise pathophysiology of HFpEF, identifying appropriate treatment strategies, and improving patient outcomes. Despite accumulating data showing the potentiality of artificial intelligence (AI)-based phenotyping using clinical, biomarker, and imaging information from multiple dimensions in HFpEF management, contemporary guidelines and consensus do not incorporate these in daily practice. In the future, further studies are required to authenticate and substantiate these findings in order to establish a more standardized approach for clinical implementation. Heart failure with preserved ejection fraction (HFpEF) is diagnosed as heart failure with a left ventricular ejection fraction (LVEF) of ≥50% and elevated left ventricular filling pressures at rest or during exercise after careful exclusion of conditions that may mimic HFpEF ,2. HFpEFThere is currently little evidence supporting the effectiveness of conventional therapies utilized for HFpEF to reduce mortality rates, such as empagliflozin in the EMPEROR-Preserved trial and dapagliflozin in the DELIVER trial. However, emerging research suggests that treatment should be tailored to the specific comorbidities present in each patient . Some ofSeveral studies have examined the relationship between HFpEF and clinical entities and comorbidities. For example, in the TOPCAT trial, it was discovered that patients with HFpEF who had been previously hospitalized for heart failure exhibited a greater likelihood of experiencing cardiovascular death, heart failure hospitalization, or aborted cardiac arrest than their counterparts who did not have a history of hospitalization . The utiSince the amount of healthcare data generated on a daily basis is overwhelming for a contemporary doctor, far surpassing the computational capacity of the human brain , machineOne method to subtype HFpEF is based on the presence of underlying clinical entities or comorbidities that contribute to the development and progression of the disease, known as clinical phenotyping A 8]. Th. Th8]. THwang et al. explored the implications of coronary artery disease (CAD) in HFpEF. The authors suggested that HFpEF patients with CAD have distinct clinical and pathophysiological characteristics compared with those without CAD. CAD may play a significant role in the progression of HFpEF, and a better understanding of this relationship could lead to the development of more effective treatments. This study provides insights into the clinical entity and underlying comorbidity of HFpEF, and it highlights the importance of considering these factors when defining and classifying HFpEF phenotypes .Shah et al. identified distinct subgroups of HFpEF patients based on their comorbidities, including obesity-related comorbidities, metabolic syndrome, and pulmonary hypertension. This study showed that these subtypes had distinct clinical, biochemical, and imaging profiles, suggesting that they may represent different disease processes. The authors proposed that this phenomapping model-based clustering approach could be used to tailor treatments to individual patients and to improve outcomes in HFpEF  Figure B.Borlaug et al. investigated the associations between specific clinical entities, comorbidities, and HFpEF subtypes. Their study included 344 patients with HFpEF who were classified into four subtypes, based on the clinical entities or comorbidities present, as follows: (1) obesity-related, (2) hypertension-related, (3) diabetes-related, and (4) idiopathic. According to this research, the HFpEF subtype associated with obesity showed a greater prevalence of metabolic risk factors and more severe diastolic dysfunction compared to the other subtypes. The hypertension-related HFpEF subtype had a higher prevalence of left ventricular hypertrophy, concentric remodeling, and worse systolic function. The diabetes-related HFpEF subtype had a higher prevalence of diabetic nephropathy, worse systolic function, and more severe diastolic dysfunction. The idiopathic HFpEF subtype had a lower prevalence of comorbidities and less severe diastolic dysfunction than the other subtypes .Uijl et al. proposed a five-cluster model, labeled Cluster 1 and Clusters 2–5, among 6909 HFpEF from the Swedish Heart Failure Registry (SwedeHF) and externally validated this in 2153 patients from the Chronic Heart Failure ESC-guideline based Cardiology practice Quality project (CHECK-HF) registry, as shown in Cardiac imaging and measurement of the cardiac structure are critical aspects in diagnosing HFpEF, as the symptoms of this condition can be nonspecific. Non-invasive measures of cardiac structure and function can assist in improving diagnostic accuracy and differentiating the sub-phenotypes of HFpEF. Additionally, imaging can exclude alternative diagnoses that mimic HFpEF, such as hypertrophic cardiomyopathy, primary valvular heart disease, cardiac amyloidosis, and pericardial disease. While two-dimensional (2-D) transthoracic echocardiography is the most commonly used imaging modality, advanced imaging techniques, including cardiac magnetic resonance imaging and 2-D speckle tracking echocardiography, are used to identify distinct HFpEF phenotypes based on left ventricular structure and function ,31,32,35Several studies have investigated the use of echocardiography to identify the imaging-based phenotypes of HFpEF. Diastolic dysfunction, a hallmark feature of HFpEF, has been well adopted in the initial classification of HFpEF . One stuAnother study evaluated left atrial function using 2-D speckle tracking echocardiography and found that left atrial strain was significantly decreased in patients with HFpEF compared with that in controls. The study also found that left atrial strain was independently associated with a higher risk of adverse events, including hospitalization and mortality .Cardiac imaging and measures of cardiac structure and function are essential for diagnosing HFpEF, excluding alternative diagnoses, and identifying imaging-based phenotypes. Although 2-D echocardiography remains the most commonly used imaging modality, CMR and 3-D echocardiography offer more comprehensive information regarding cardiac structure and function. These imaging techniques may have important prognostic implications and help guide management strategies in patients with HFpEF.Personalized management of different HFpEF phenotypes using clustering targeting more specific molecular or pathological etiology driving underlying mechanisms has been proposed in several studies ,40,41,42Among the five clusters, patients with HFpEF in this group had a median age of 59 years and a relatively low burden of comorbidities, making them the youngest of the cohorts. The most common comorbidities in Cluster 1 were hypertension (46%) and obesity (42%). The principles of management for this group are to control blood pressure and reduce body weight. It is worth mentioning that cluster 1 includes patients who have recovered HFrEF, due to the higher percentage of implantable cardioverter-defibrillator or cardiac resynchronization therapy.In addition to the implantable devices, quite a few medications have demonstrated an established efficacy in previous HFpEF trials. Those drugs were renin–angiotensin–aldosterone system (RAAS) antagonists such as angioten-sin-converting enzyme inhibitors (ACEis), angiotensin II receptor blockers (ARBs), mineralocorticoid receptor antagonists (MRAs), and angiotensin receptors/neprilysin inhibitor (ARNi), which could be considered as first-line agents for the management of HFpEF. Lifestyle modifications were strongly suggested for this cluster. Significant improvements in quality of life and exercise tolerance were observed as a result of weight reduction, which was found to be safe. In addition to these benefits, weight loss in patients with HFpEF has been shown to have a positive impact on cardiac function and metabolic parameters, potentially leading to reduced doses of diuretics, antihypertensive agents, and diabetes medications.The individuals belonging to Cluster 2 were relatively older compared to those in Cluster 1, having a median age of 77 years. This cluster included patients with HFpEF characterized by AF without diabetes. Principles of management for this cluster align with the AF Better Care (ABC) pathway, including rate/rhythm control in AF management, as follows: (A) avoiding thromboembolic events with the use of anticoagulation. (B) better management of symptoms with personalized, symptom-directed decisions on rate or rhythm control. Rate control involves the use of beta-blockers/non-dihydropyridine (DHP) calcium channel blockers (CCBs) (diltiazem or verapamil)/digoxin; rhythm control involves the use of amiodarone/dronedarone or AF ablation. (C) Effective management of cardiovascular and coexisting conditions, including attention to psychological factors and lifestyle. Following the ABC pathway has been shown to lead to improved outcomes, including decreased risks of all-cause mortality, cardiovascular mortality, stroke, and hospitalization due to cardiovascular reasons. It is important to avoid excessive rate control in patients with both HFpEF and AF, as it may diminish their chronotropic reserve. In a trial comparing strict (<80 bpm) and lenient (<110 bpm) rate control in patients with AF, which may have included individuals with undiagnosed HFpEF, no significant differences in outcomes were observed.Among the five clusters, Cluster 3 patients were the oldest  with the highest N-terminal pro b-type natriuretic peptide (NT-proBNP) values. It was reasonable to eliminate any meaningful clinical phenotyping for this cluster, as it presented with an anticipated higher risk for an ominous outcome. Clinically, the principle of for the elderly is to reduce hospitalization rates and improve quality of life. Decongestion of diuretics has been shown to reduce hospitalization rates. In the TOPCAT trial, spironolactone was associated with a decrease in heart failure hospitalization rates compared with the placebo . This clCluster 4 was composed of patients who had a median age of 71 years and were identified as having diabetes but not AF. Serum glucose control is the mainstay of this cluster. SGLT2 inhibitors have emerged as a critical component of HFrEF therapy as they possess favorable pleiotropic effects on various body parts such as the kidney, liver, pancreas, blood vessels, and adipose tissue, apart from their primary role as an antidiabetic medication. The EMPEROR-Preserved trial was groundbreaking in the study of HFpEF as it compared the effects of empagliflozin with a placebo in patients with ejection fractions above 40%, irrespective of whether they had diabetes or not. The trial demonstrated a significant reduction in the risk of heart failure-related hospitalizations and cardiovascular mortality, as well as an improvement in renal outcomes.According to the DELIVER trial, dapagliflozin is superior to placebos in decreasing cardiovascular deaths and hospitalizations due to heart failure in patients with mildly reduced or preserved ejection fractions. Additionally, the study showed that dapagliflozin was effective in patients who previously had ejection fractions below 40% but later saw an increase to over 40%.Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are also associated with positive cardiovascular effects. A recent meta-analysis involving 592 patients revealed that liraglutide was connected with significant enhancements in the left ventricular diastolic function.Cluster 5 was a union of Clusters 2 and 4. This cluster had a median age of 82 years, and its members had comorbidities of both diabetes and AF. In the DECLARE-TIMI 58 trial , dapagliflozin reduced the incidence of AF in patients with diabetes . EffortsObesity as a common etiology and co-morbidity for HFpEF has been shown to induce activated sympathetic system and RAAS  and further promote systemic inflammation ,46, whicElevated circulating levels of aldosterone, either directly from adipocytes or released from the adrenal gland in response to leptin through the adipokines-cell-signaling molecules secreted , along with the attenuated anti-aldosterone effects from natriuretic peptides due to an increased neprilysin activity in obesity, may potentiate  the deleImportantly, an activated leptin–aldosterone–neprilysin axis with sustained increases in aldosterone and neprilysin concentration may in turn accelerate the accumulation and inflammation of epicardial fat ,53. ReceIn summary, the identification and characterization of HFpEF phenotypes are important for guiding diagnosis, management, and research into novel treatment strategies. It was a prerequisite for us to identify that the presence of ischemic heart disease by itself induces prognostic implications. Given the complexity of HFpEF, a personalized approach to management that considers the underlying mechanisms and comorbidities in each patient is needed and might help to solve the puzzle of this challenging syndrome.


This review aims to provide an overview of the recent advances in biofriendly MNM design using biocatalysis as the predominant driving force, towards practical applications in biotechnology and environmental technology.Micro/nanomotors (MNMs) are tiny motorized objects that can autonomously navigate in complex fluidic environments under the influence of an appropriate source of energy. Internal energy driven MNMs are composed of certain reactive materials that are capable of converting chemical energy from the surroundings into kinetic energy. Recent advances in smart nanomaterials design and processing have endowed the internal energy driven MNMs with different geometrical designs and various mechanisms of locomotion, with remarkable travelling speed in diverse environments ranging from environmental water to complex body fluids. Among the different design principals, MNM systems that operate from biocatalysis possess biofriendly components, efficient energy conversion, and mild working condition, exhibiting a potential of stepping out of the proof-of-concept phase for addressing many real-life environmental and biotechnological challenges. The biofriendliness of MNMs should not only be considered for  Accordingly, biocatalysts in general possess higher catalytic efficiency in mild working conditions, endowing biocatalytic MNMs with low cost and high energy efficiency. The great biocompatibility of the MNMs systems is expected to play an essential role in the development of stepping out of the proof-of-concept phase for addressing many real-life environmental and biotechnological challenges.Inspired by the diverse molecular motors in nature Cross , recent et al. et al. et al. et al. et al. et al. et al. et al. Recent advances in biocompatible MNMs research have made them become promising candidates for addressing many bio-related challenges owing to their characteristics. These small MNMs present an advantage in overcoming cellular barriers and improving cellular uptake, which made them good nanocarrier substitutes for drug delivery , chemical fuel consumption (e.g. H2O2) and external field propulsion such as electrical field, magnetic field, light and ultrasound . Based on the bio-specificity of the chemical fuels, some of the enzyme-powered MNMs can be applied for chemotaxis-driven targeting transportation    Gáspár , are amoet al. et al. et al. et al. Besides diverse inorganic materials, synthetic polymers have also been developed to fabricate biofriendly MNMs due to their excellent molecular tunability and facile synthetic procedures, which can equip polymer-based MNMs with proper physicochemical properties, flexible morphologies, diverse functionalities and non-toxicity  micromotors  (PEG) was conducive to size and shape control in nanoscale, allowing small polymersomes to transform into stomatocytes 167 and the enzymes were mixed with the glassy stomatocytes followed by closing of the stomatocyte neck with solvent addition method. The constructed motors were propelled by the enzymatic reaction and exhibited high speed in biologically relevant fuels. Our group reported a universal and facile strategy to encapsulate almost any kinds of biocatalysts in MOF nanoparticles through a one-step biomineralization process Due to the chemical-to-kinetic energy conversion ability, the great mobility against diffusion limit, and continuous stirring of the surrounding environment, MNMs hold great promise for diverse applications from environmental remediation to nanomedicine. Many fundamental studies on MNMs systems are primarily focused on motion and speed manipulation but lack of actual practical applications. However, these fundamental studies shed light to future development in more practical applications employing MNMs. Here we provide a non-comprehensive highlight of several studies on the enzyme-powered, biofriendly MNMs for motion manipulation towards future practical applications.et al. The primary design of biocompatible micromotors is simply composed of a micro-engine body and a propelling module. Schmidt and coworkers reported a rolled-up Ti/Au microtube with covalently bound catalase on the inner layer  (Sanchez2CO3 to form hollow mesoporous silica nanoparticles (HMSNPs), which were further modified with amino groups and half-capped with a 10 nm silicon dioxide layer  solution  (Orozco Raphanus sativus), which was rich with catalase and peroxidase enzymes  (PEDOT) microtubes as the backbone and anchoring the catalase enzyme on a mixed self-assembled binary monolayer coupled with EDC/NHS for oxygen bubble propulsion   multilayer rocket consisted of heat-sensitive gelatin hydrogel, gold nanoparticles, doxorubicin and catalase    (Patino et al. In another work, Zhao and coworkers reported Janus micromotors for circulating tumor cells detection with motion-capture-ratiometric fluorescence changes  (Zhao etIn this review, we capture the recent research efforts in biocompatible MNMs that operate on enzyme-powered catalysis with different constructions and applications ranging from biomedicine to the environment. The rapid explosion of nanomaterial research in the past two decades has enabled diverse propulsion mechanisms and possible applications. At present, the full promise of MNMs constructs to real-world applications has still not been met as the field has only begun to mature recently. One of the major challenges remained for real-world application is the compatibility of MNMs with the biological system and the natural environment. There are still works to be performed on designing new techniques and strategies for integrating biocompatible MNMs with diverse applications. Another important consideration in engineering these MNMs is the endogenous available energy source or, at least, biofriendly fuels available for their motion. The excessive amount of fuels required for MNM motion could be harmful to the biological system and natural environment. Therefore, it is important to develop more energy efficient motors with less fuel demand. The current biocompatible MNMs generally revolve around enzyme biocatalysis, particularly catalase for decomposing hydrogen peroxide. In contrast, biological system utilizes thousands of different enzymes to catalyze diverse biochemical reactions. This represents new opportunity for MNMs by exploiting new biocatalytic pathways. In addition, the optimization of MNMs properties — such as size, morphology, geometry, and catalyst distribution — has shown great influence on the motion performances, which should play an important role in guiding or enhancing MNMs development. It is anticipated that advancements in these areas will lead to an improved ability in designing and optimizing biocompatible MNMs that can be ultimately employed for many applications.Ziyi Guo, Jian Liu, Da-Wei Wang, Jiangtao Xu and Kang Liang declare that they have no conflict of interest.


Carotid artery disease has traditionally been assessed based on the degree of luminal narrowing. However, this approach, which solely relies on carotid stenosis, is currently being questioned with regard to modern risk stratification approaches. Recent guidelines have introduced the concept of the “vulnerable plaque,” emphasizing specific features such as thin fibrous caps, large lipid cores, intraplaque hemorrhage, plaque rupture, macrophage infiltration, and neovascularization. In this context, imaging-based biomarkers have emerged as valuable tools for identifying higher-risk patients. Non-invasive imaging modalities and intravascular techniques, including ultrasound, computed tomography, magnetic resonance imaging, intravascular ultrasound, optical coherence tomography, and near-infrared spectroscopy, have played pivotal roles in characterizing and detecting unstable carotid plaques. The aim of this review is to provide an overview of the evolving understanding of carotid artery disease and highlight the significance of imaging techniques in assessing plaque vulnerability and informing clinical decision-making. Traditionally, the clinical assessment of carotid artery stenosis has been based on the degree of luminal narrowing, which has been considered the most reliable predictor of intervention according to international guidelines. The 2017 European Society of Vascular Surgery (ESVS) guidelines [Risk stratification based solely on carotid stenosis has become completely outdated. In fact, in the recently published 2023 ESVS guidelines, patients with only a single risk factor of carotid stenosis greater than 80% are no longer considered to be at high risk of stroke .These advancements in the knowledge of the natural progression of atherosclerosis has enabled the identification of distinct characteristics of carotid plaques that are linked to an elevated risk of stroke, consequently introducing the concept of the “vulnerable plaque”, referred to by some as the “unstable plaque” ,6. SeverSeveral non-invasive imaging modalities, including US, CT, high-resolution MRI, and nuclear imaging techniques, have been used to identify these plaque characteristics with the aim of achieving an accurate risk stratification and providing guidance for clinical decision-making.In recent years, advancements and progress in imaging modalities have facilitated the development of intravascular studies, representing a significant breakthrough in the characterization and detection of vulnerable carotid plaques. Given their superior image resolution compared to non-invasive imaging methods, intravascular imaging techniques such as intravascular ultrasound (IVUS), optical coherence tomography (OCT), and near-infrared spectroscopy (NIRS) have emerged as promising modalities for the assessment of culprit lesions in carotid artery disease. However, the translation of these imaging findings into routine clinical practice remains a challenge.This review aims to provide a comprehensive understanding of the characteristics of unstable carotid plaques, emphasizing the detection of biomarkers derived from novel imaging techniques. In addition, it highlights recent advancements in intravascular carotid imaging techniques and also focuses on the existing clinical evidence supported by non-invasive imaging modalities, elucidating their role in the management of carotid artery disease.Yock et al. introduced IVUS in 1988 as the pioneering intravascular imaging device specifically designed for coronary applications [IVUS utilizes miniature high-frequency transducers (20–45 MHz) placed within an angiographic catheter to obtain real-time, high-resolution images of vascular structures perpendicular to the long axis during pull-back. By analyzing the strength and characteristics of the echoes, IVUS provides valuable information regarding plaque composition and allows for the determination of signs of plaque instability .Although grayscale IVUS can differentiate calcified from non-calcified plaques, it cannot accurately determine non-calcified plaque tissue composition due to post-processing limitations. VH-IVUS utilizes sophisticated radiofrequency analysis of echo signals to generate multiple spectral parameters, which are then converted into color histograms for the analysis of different plaque components . By emplIVUS provides valuable information for the quantitative assessment of plaque thickness, cross-sectional area, plaque burden, and the remodeling index. It also allows for qualitative assessment, including the identification of the thin fibrous cap and the analysis of plaque composition. This analysis helps differentiate plaque components and assess plaque instability ,12 Figu.Thin cap fibroatheroma (TCFA) is a type of plaque characterized by a plaque burden exceeding 40% and a large necrotic-rich core (>10%), without apparent fibrotic tissue observed in consecutive frames using VH-IVUS ,14. In tIVUS allows the quantitative analysis of plaque thickness by means of the measurement of the distance between the luminal surface and the leading edge of the plaque. Comparing cross-sectional areas at different locations within the vessel helps to identify focal stenosis or diffuse disease. It also calculates the percentage of the vessel cross-sectional area occupied by the plaque corresponding to plaque burden. IVUS has confirmed that plaque erosion is characterized by an eccentric plaque with a thick fibrous cap while plaque rupture is observed when a hypoechoic cavity within the plaque is connected to the lumen . RuptureIVUS-based assessment of inflammatory activity relies on the detection of features such as neovascularization and macrophage infiltration. IVUS can identify neovascularization as microvessels originating from the adventitial side and penetrating into the plaque. It also can calculate the remodeling index by dividing the external elastic membrane area at the site of maximal plaque burden by the average external elastic membrane area in reference segments . The remIVUS plays a crucial role in guiding interventional procedures, providing real-time visualization of the vessel and the stented segment, aiding in optimal stent sizing, placement, expansion, and apposition . IVUS enIn the prospective multicenter VICTORY registry study, IVUS and IVUS-VH examinations performed during carotid artery interventional therapy were deemed feasible and safe, offering valuable insights into the qualitative and quantitative composition of carotid plaques . AnotherWidespread adoption of IVUS to identify risk factors in asymptomatic patients in standard clinical practice is currently facing challenges due to its invasiveness and high cost. Although IVUS demonstrates high sensitivity and specificity in detecting large dense calcified plaques or spot calcifications , one of Traditional IVUS imaging provides two-dimensional cross-sectional images, limiting the assessment of plaque characteristics in the longitudinal plane. Three-dimensional (3D) IVUS allows for the reconstruction of volumetric images of the vessel and plaque, providing a more comprehensive assessment of plaque burden and morphology. Hybrid imaging systems that combine IVUS with NIRS or OCT catheters allow the simultaneous analysis of both vessel structure and plaque composition and have the potential to overcome the limitations of each technique, thus improving the accuracy of plaque characterization.The integration of machine learning with artificial intelligence (AI) could be valuable in combining intravascular imaging findings with biomarkers to identify factors associated with plaque instability and progression .Traditionally, OCT has served as a non-invasive imaging diagnostic method that provides valuable insights into the functional blood vessels within the eye and allows for the study of various retinal conditions, such as macular telangiectasia, impaired perfusion, microaneurysms, capillary remodeling, certain types of intraretinal fluid, and neovascularization . In 1991OCT is an invasive microscopic imaging technology that utilizes reflected near-infrared light and interferometry to generate high-resolution images of the tissue microstructure of the carotid artery with exceptional clarity ,32.The OCT system employs rapid scanning of the catheter to acquire multiple cross-sectional images, known as B-scans, along the length of the artery. The catheter is slowly withdrawn, and the scanning process is repeated at different pullback speeds to capture a three-dimensional representation of the structure of the vessel wall and assess plaque morphology, composition, and vulnerability  as well In terms of vulnerable plaques, OCT provides visualization and assessment of various characteristics such as cap thickness (with thin caps defined as those ≤65 μm), lipid core detection, calcification, cholesterol crystallization, IPH, plaque erosion, plaque rupture or thrombi, and neovascularization. Moreover, OCT allows for the observation and quantification of inflammation within unstable plaques by measuring macrophage infiltration in the fibrous cap and subintimal lipid accumulation . PreviouLipid cores appear as low-intensity regions with distinct borders on OCT images. Necrotic cores appear as a low-signal area in OCT imaging with an indistinct border, an absence of backscattering signal, and a rapid signal drop-off. OCT also demonstrates high sensitivity and specificity in detecting lipid-rich plaques, as verified by autopsy specimens  . OCT canOCT provides a highly detailed visualization of intimal thickening, where the intima layer exhibits a strong backscattering signal at its internal boundary, gradually decreasing in intensity towards the outer layers . MeasureIn OCT imaging, inflammation is characterized by a highly intense speckle signal observed in regions adjacent to the fibroatheroma, varying in size. It is crucial to differentiate these areas from cholesterol crystals, elastic lamina, or calcium deposits . It shouThe clinical applications of OCT in carotid stenosis encompass both diagnostic and therapeutic purposes. The use of OCT in characterizing vulnerable carotid plaques has significant clinical implications for risk stratification and patient management. By providing detailed information on plaque morphology, fibrous cap thickness, lipid-rich regions, and surface features, OCT can help to identify high-risk plaques that are prone to rupture and subsequent ischemic events. This information can assist in determining the optimal treatment strategy for individual patients and the need for invasive interventions.OCT plays a crucial role in guiding therapeutic interventions for carotid artery disease. It provides real-time feedback during interventions, revealing features that were not visualized using other imaging modalities like CT and MR angiography, such as free intraluminal thrombus, dissection, TCFA with an underlying ulcerative plaque and filling defects inside or adjacent to stents, or an undersized stent . In viewHowever, the prognostic value of plaque morphology and composition in terms of stroke risk has not been established in large prospective studies. Therefore, it remains challenging to set up OCT in routine clinical practice and determine its impact on patient outcomes.Improvements in imaging devices, including a higher resolution and faster acquisition rates, are expanding the capabilities of OCT in visualizing microstructural details. Additionally, the development of advanced image analysis algorithms and machine learning techniques has enabled automated identification and quantification of plaque features, reducing the subjectivity and time required for interpretation. Regardless, there is a need to develop a validated algorithm for plaque characterization that can help to facilitate the standardization of OCT image detection of plaque instability. This goal has been achieved by He et al., who designed a machine learning algorithm for the characterization of atherosclerotic plaque components by intravascular OCT using ex vivo carotid plaque tissue samples . A totalNear-infrared spectroscopy (NIRS) is a novel imaging technique that utilizes near-infrared light to analyze the absorption pattern of cholesterol molecules within the vessel wall, enabling the detection of lipid-rich plaques with high accuracy . NIRS alHowever, there are limitations that have hindered its independent use in clinical settings. Firstly, NIRS only provides information regarding the lipid composition of plaques and does not offer a comprehensive morphological assessment. Secondly, it cannot visualize or evaluate the size of the lumen, external vessel wall, or plaque burden. Lastly, NIRS lacks the depth resolution required to precisely locate the necrotic core within the plaque and differentiate TCFA from thick-cap fibroatheromas.X-axis and the circumferential position in degrees on the Y-axis, resembling the longitudinal splitting of the coronary vessel. In studies comparing NIRS to IVUS alone, NIRS has demonstrated superior performance in identifying lipid core plaques [It is worth noting that NIRS provides limited anatomical information and is commonly used in conjunction with intravascular ultrasound (IVUS) to generate a “chemogram” or probability map. The chemogram represents the pullback position in millimeters on the  plaques . Some st plaques . Its intMultimodal imaging approaches, combining different imaging modalities such as IVUS, OCT, and NIRS, have emerged to overcome the limitations of individual techniques and provide a comprehensive assessment of plaque morphology and composition as well as a prediction of disease progression. Studies have shown that a hybrid approach with IVUS and NIRS imaging is particularly advantageous in identifying the distribution of lipid core plaques and exploring the relationship between vascular geometry, shear stress, and plaque composition . While IHowever, IVUS-NIRS also has limitations as the low resolution of IVUS affects the evaluation of cap thickness and luminal boundary definition in the presence of thrombosis or severe intraplaque bleeding. Alternatively, it has been suggested to integrate the two approaches of IVUS and OCT in order to benefit from the deep penetration of IVUS and the high resolution of OCT . The appCarotid angiography is considered to be the gold standard in evaluating carotid artery disease. In the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and European Carotid Surgery Trial (ECST), angiography served as the reference standard for assessing luminal stenosis in carotid extracranial disease ,63. BaseIn as early as 1978, Moore et al. noted that the presence of ulceration observed on angiography could identify patients at high risk of subsequent strokes . In the US has been widely used since the 1980s, particularly duplex ultrasonography, for quantifying the degree of carotid stenosis by measuring flow velocity and flow ratios, and it is the modality of choice for the initial evaluation of carotid artery disease ,71. In aOriginally, the appearance of a plaque was either classified as echogenic  or echolucent  . Later, In order to reconcile the discrepancies between ultrasound classification and histological findings, computer-assisted image analysis has been used to quantify plaque echogenicity. Nowadays, there are several possibilities for analyzing US images, such as the Gray Scale Median (GSM), Pixel Distribution Analysis (PDA), and Virtual Histology (VH).GSM values are calculated by digitizing B-mode images and subsequently processing them with Adobe Photoshop . The Imaging in Carotid Angioplasty and Risk of Stroke study, a large-scale study that examined the relationship between GSM and the risk of stroke during carotid artery stenting, demonstrated that the rate of stroke and TIA was greater in patients with plaques that had GSM values of <25 than in patients with GSM > 25 .Another approach is PDA, which maps individual tissue components within the carotid plaque image . PDA digDespite the high expectations projected onto these imaging techniques, the results of the study conducted by Denzel et al. were not as encouraging. They compared B-mode images of 107 carotid endarterectomy specimens and their GSM values to a histologic classification consisting of only three groups . Only 46% of the cases showed agreement between the GSM and the histopathological findings . CorrelaThree-dimensional US provides better visualization of plaque geometry, surface irregularity, luminal plaque borders, intima-media layers, and ulceration compared to 2D ultrasound. It enables differentiation between ulceration and gaps between adjacent plaques, enhancing diagnostic accuracy , as well2) may indicate vulnerable plaques, while a discrete white area (DWA) is related to neovascularization [Contrast-enhanced ultrasound (CEUS) is an innovative diagnostic tool that utilizes microbubble contrast agents to offer an objective evaluation of carotid plaque vulnerability. It allows for the visualization of neovessels within the plaque and plaque ulceration, assisting in distinguishing between occlusion and stenosis . During rization .Van den Oord et al. found that CEUS changed the risk category in asymptomatic patients previously classified by the traditional risk stratification model by calculating the Prospective Cardiovascular Munster Heart Study (PROCAM) risk . Hamada The TCFA can be visualized on ultrasound as an echogenic structure that reflects more echoes than the surrounding plaque and blood . The thiOn ultrasound, ulceration is defined as a focal depression of at least 2 mm deep and 2 mm long, with a distinct wall at its base, and a region of reversed flow at the site of the recess ,102. HowPlaques with higher enhancement have been correlated with a greater neovascularization on histology analysis . Camps-RUS allows for the measurement of flow velocity, detection of stenosis severity, and visualization of plaque echogenicity. It can also provide information on plaque vulnerability based on the plaque surface and composition ,73. PlaqIn addition, the development of computer-assisted image analysis has reduced inter-observer variability in ultrasound scan analysis. The Imaging in Carotid Angioplasty and Risk of Stroke (ICAROS) trial demonstrated that increased echolucency of the carotid plaque, measured by GSM, is a risk factor for stroke during and immediately after carotid artery stenting . HoweverRecent advancements in integrated backscattering (IB) analysis have created a map-like image that describes the mixed composition of the plaque, providing more detailed information than averaged IB values. Custom software, such as iPlaque, allows the visualization of different tissue components of a plaque in a color-coded display, based on previously established IB threshold values .A limitation of GSM analysis is that by analyzing the median gray value of the plaque as a whole, it may overlook significant heterogeneity within the plaque and misrepresent instability if a plaque contains both soft and hard components. Texture analysis is an alternative approach that takes into consideration the heterogeneity and spatial variations in pixel intensity within the plaque. Acharya et al. used semi-automatic texture features and features based on a trace transform matrix to classify plaques as symptomatic or asymptomatic, achieving high accuracy rates .While the widespread applicability of these methods is still limited, recent studies have suggested that the grayscale algorithms used for two-dimensional (2D) images can be applied to three-dimensional (3D) ultrasound for whole-plaque analysis . The comTranscranial Doppler ultrasonography (TCD) is a non-invasive and portable imaging technique that is used to visualize the intracranial blood vessels. To perform imaging, a sector-array transducer with a low-frequency (2 MHz) is typically used to allow the signal to penetrate through the skull.The primary role of TCD in carotid imaging is to evaluate cerebral microembolic signals (MESs), and the middle cerebral artery is the preferred artery to monitor . In patiAdditionally, TCD is useful in assessing the risk of stroke in these patients, especially when combined with other imaging modalities. The combination of plaque echolucency on B-mode ultrasonography and MESs on TCD has been associated with a 10-times-greater risk of stroke in patients with asymptomatic carotid stenosis . The comElastography is a valuable technique for evaluating the stiffness of a plaque, which reflects its histological composition . By measTwo methods of elastography are commonly used: strain elastography (SE) and shear-wave elastography (SWE). SE measures the displacement of the plaque caused by external forces such as blood pressure oscillations or manual compression of the probe and provides semi-quantitative parameters like strain, strain velocity, or strain rate using deformation estimating algorithms. On the other hand, SWE involves the emission of shear waves into the tissue through an acoustic radiation force impulse. These waves propagate perpendicularly to the impulse, and the technique measures their velocity, expressed as Young’s modulus (YM). YM defines tissue resistance to elastic deformation and quantifies the stress required to achieve a unit of deformation, thus providing a measure of tissue elasticity .Plaques with a higher lipid content exhibit significant elastic deformation, a lower YM, and lower shear-wave velocities (SWV). In contrast, more rigid tissues like calcified plaques demonstrate less elastic deformation and higher SWV . A lowerThe sensitivity and specificity of elastography vary depending on the reference method used. When compared to MRI, sensitivity was reported as 71.4%, and specificity was 87.1%. In comparison to histology, sensitivity decreased to 50%, while specificity reached 100% .While elastography indices cannot replace the grading of stenosis for determining eligibility for surgery, they can provide additional information to improve the detection of unstable plaques and patient risk stratification. However, further large-scale studies with longitudinal follow-up are warranted to enhance our understanding of this technique.Computational fluid dynamics (CFD) technologies are used to analyze and quantify fluid flow behavior in various systems, including the cardiovascular system. In the context of atherosclerotic plaques, CFD allows for the calculation and visualization of hemodynamic forces acting on the plaque, such as wall shear stress (WSS) and axial plaque stress (APS). These technologies have undergone significant progress, now enabling the utilization of more accurate and patient-specific geometric models derived from sources like coronary computed tomography angiography (CTA). By discretizing the coronary models into volumetric meshes, CFD analysis can simulate blood flow and pressure patterns, providing valuable insights into the behavior of atherosclerotic plaques and their susceptibility to rupture or complications .WSS is a critical factor in the development and rupture of atherosclerotic plaques. High WSS has been observed to co-occur with plaque rupture in various artery imaging studies. However, solely considering WSS magnitude may not fully predict the rupture process. To address this, researchers have introduced APS as an alternative measure to estimate plaque rupture risk. APS has shown statistical associations with necrotic-core plaques and functional ischemia in the coronary arteries ,126.Li et al. established a clear association between plaque geometry and stress, as measured by WSS and APS. Plaque severity and eccentricity were identified as independent factors linked to acute vascular events in coronary plaques, while the lengths of proximal and distal segments indicated potential sites of rupture. APS was found to be directly linked to plaque rupture, especially in the distal segments . AnotherThe enhanced capabilities of these hemodynamic and geometric indices have opened up new possibilities for studying plaque-related pathologies and guiding personalized treatment strategies.Computed tomography (CT) is a non-invasive imaging modality that has proven to be an excellent tool for carotid stenosis evaluation and it also provides a viable alternative for assessing vessel wall size, high-risk plaque burden, morphological characteristics, and vulnerability, with a relatively high accuracy  Figure .There are two primary CT techniques used for plaque characterization: multidetector-row CT angiography (MDCTA) and dual-source CT (DSCT). MDCTA allows for reconstructions in multiple planes  and provides high spatial and contrast resolution, similar to MRI . MDCTA hDSCT utilizes two different X-ray sources operating at different energies to achieve distinct Hounsfield units (HUs) within the same tissue. This allows for improved tissue differentiation and advanced postprocessing techniques. DSCT also can be combined with bone-removal algorithms, enabling better visualization of the vasculature and providing a high spatial resolution for multiplanar reformats . CompareAs a general guideline, lower plaque density is indicative of increased instability . The thiA plaque ulcer is characterized by the presence of an intimal defect that causes the contrast material to extend beyond the lumen and into the surrounding plaque on CT imaging. MDCTA can detect ulceration with moderate to good sensitivity (60–94%) and specificity (70–99%) when compared to histological analysis ,137.CT can also identify and quantify neovascularization as well as plaque volume and vascular remodeling ,132. In MDCTA is already integrated as standard care for the evaluation of carotid plaques. Observation of the characteristics of plaque instability in CT studies would greatly reduce the need for further imaging assessment. However, stratification tools for vulnerable carotid plaque diagnosis in CT studies have yet to be developed, as the literature lacks comparative studies with systematic reporting of outcomes between the two imaging modalities. In particular, MDCTA has been used to monitor the effects of statins, showing modifications in plaque composition over time, with a progressive reduction in fatty subcomponents ,139. AddA study by Ball et al. utilized a novel technology called tomographic ultrasound (tUS) . This teOther recent studies suggest that high shear stress contributes to the progression of unstable plaques , but litHistological correlation studies have demonstrated the high sensitivity and specificity of in vivo high-resolution MRI in identifying vulnerable plaque characteristics . The besThere are multiple pulse sequences available for characterizing plaques using MRI. One frequently utilized technique is rapid spin echo (RSE), which enables imaging with T1-weighting, T2-weighting, and proton density weighting (PDW) .Magnetization-prepared rapid-acquisition gradient echo (MPRAGE) combines the use of magnetization preparation with rapid image acquisition using gradient echoes and it reliably detects IPH and LRNC on T1-weighted images .The black-blood technique is commonly employed for plaque imaging. It employs an RSE sequence with double inversion recovery preparatory pulses, enhancing the contrast between the dark lumen and the vessel wall. However, this technique often necessitates longer examination times .To accurately characterize plaque morphology, fat suppression is critical. This technique is utilized in all sequences to suppress the signal from the subcutaneous fat, improving the contrast between different plaque components as well as between the carotid wall and surrounding tissues. Fat-suppressed T1-weighted images are particularly valuable in differentiating the high T1 signal of intraplaque lipid from that of IPH .Contrast-enhanced images play a pivotal role in distinguishing various plaque components. Gadolinium (Gd)-based contrast imaging can be employed to evaluate plaque neovascularity and differentiate a necrotic core from fibrous tissue on T1-weighted images ,152.On MRI, the fibrous cap can be visualized as a thin band adjacent to the lumen. It appears hypointense on time-of-flight (TOF)-weighted images and isointense on T1-weighted (T1W), T2-weighted (T2W), and proton-density-weighted (PDW) images. A ruptured FC will demonstrate a disrupted, dark band on CE-T1W with an irregular luminal surface on all images, although distinguishing between the two is still challenging . Using 3MRI identifies ulceration using a variety of imaging sequences such as 3D TOF, T1, proton density, T2, and contrast-enhanced T1 . In MRI Plaque enhancement on post-contrast T1-W MR images is associated with plaque vulnerability, neovascularization, and macrophage infiltration . DynamicMRI is currently the most promising imaging modality for identifying vulnerable plaque components, thanks to its high soft-tissue contrast and high in-plane resolution. Studies have shown that MRI can detect most of the described plaque characteristics with moderate to good agreement ,155,158.Studies involving both asymptomatic and symptomatic patients with moderate carotid stenosis (<70%) have shown that MRI findings of IPH are associated with a higher hazard ratio for future ipsilateral ischemic events ,155,160.There is significant interest and ongoing research regarding potential biomarkers that are specifically designed to target molecules present in unstable atherosclerotic lesions. Superparamagnetic iron oxide (SPIO) particles have become the favored MR contrast agent that targets specific molecules or cells such as elastin, fibrin, or vascular cell adhesion molecule 1 . These pOne difficulty with multi-contrast carotid plaque MRI is needed to co-register multiple sequences. A newly developed 3D sequence to obtain three different contrast weightings  during a single 5-min acquisition can streamline carotid plaque imaging and analysis. The multi-contrast atherosclerosis characterization (MATCH) sequence was used in 53 consecutive patients, and it was comparable, if not superior, to conventional multi-contrast carotid plaque MRI in identifying and quantifying major carotid plaque components . In anotAnother area of future research could focus on the correlation between carotid plaque characteristics and cerebral damage in patients with silent cerebral ischemic events who are at high risk of a future stroke. The 7-Tesla MRI has proven to be superior in visualizing cerebral microbleeds and microinfarcts in symptomatic patients with high-grade stenosis than 1.5-Tesla and 3-Tesla .However, the current manual processing of atherosclerotic plaque features derived from MRI wall imaging data is subject to inter- and intra-observer variability and is a time-consuming process. Therefore, automated segmentation techniques have been developed to overcome these limitations .Positron emission tomography (PET) is a medical imaging technique that uses radioactive tracers to assess the biological processes related to atherosclerosis, such as intraplaque inflammation, microcalcification, and intraplaque angiogenesis. Moreover, 18F-fluorodeoxyglucose (18F-FDG) is currently the most validated tracer for imaging plaque inflammation, particularly in vulnerable carotid plaques, where high FDG uptake has been shown to correlate with macrophage accumulation . In addiThe primary molecular imaging technique used for assessing carotid plaques is 18F-fluorodeoxyglucose (FDG) PET/CT. FDG is partially metabolized through glycolysis within the atherosclerotic plaque, and serves as an indicator of plaque inflammation and hypoxia . IntraveTawakol et al. were the first to identify a histological association between plaque inflammation and the degree of 18F-FDG uptake . The abuSpecial consideration is needed when utilizing FDG-PET/CT for plaque characterization. The concentration of FDG in the blood pool can affect contrast resolution, particularly when evaluating small areas like carotid plaques. The optimal timing for imaging following FDG administration is a subject of debate. The carotid maximal standardized uptake value (SUVmax) at 180 min is more strongly associated with a 10-year risk of fatal cardiovascular disease compared to imaging at 90 min, as well as the quantification of atherosclerotic plaque inflammation .Researchers have explored the combination of FDG-PET to detect active inflammation and MRI to identify morphological features indicative of higher risk, aiming to optimize risk stratification. Truijman et al. found only a weak correlation between plaque inflammation on PET and neovascularization detected by dynamic contrast-enhanced (DCE) MRI, suggesting the complementary nature of these two techniques . CalcagnIn a study of patients undergoing carotid endarterectomy (CEA) after FDG-PET/CT, SUVmax was associated with an increased CD68 concentration, a marker of macrophage activity . TawakolPET is a validated imaging technique for plaque inflammation-related metabolism and plaque instability . AdditioSeveral studies have also reported a link between FDG uptake and the risk of future events in both asymptomatic and symptomatic individuals . Skagen The development of novel PET tracers is an active area of extensive research. Some of these novel tracers, including 18F-FMISO, 68Ga-NOTA-RGD, and 18F-NAF, are being studied in humans as alternative markers of inflammation and potential markers for microcalcification, respectively, with some success ,183,184.In terms of the translation of promising PET tracers into the clinical setting, the co-registration of PET images with CT or MRI PET has limited spatial resolution (3–5 mm), which restricts the direct quantification of vulnerable plaques in smaller vessels. To address this issue, hybrid scanner constructs, such as PET/CT and PET/MRI, are essential, with MRI potentially providing additional benefit over CT as it provides better visualization of the vessel wall .Although computed tomography (CT), magnetic resonance imaging (MRI), and sonography have demonstrated their effectiveness in detecting key markers of carotid plaque vulnerability, they have certain limitations in capturing cellular markers at a microscopic scale. In this context, optical coherence tomography (OCT) emerges as a promising and dynamic imaging-based modality for the real-time visualization of microvascular structures. OCT offers an impressive spatial resolution of around 10 μm in tissue , which iOne common misconception regarding OCT is that it can replace intravascular ultrasound (IVUS) . In factCTA and MRA have been the cornerstones, along with US for the imaging of carotid artery disease. Arteriography has been largely sidetracked in recent decades due to its invasive nature and associated risks of complications. CTA has demonstrated its effectiveness in evaluating stenosis, while MRA offers detailed information about the morphology of atherosclerotic carotid lesions. MRA studies have demonstrated superior ability in distinguishing vulnerable carotid plaque characteristics such as TFCA, LRNC, IPH, plaque ulceration, and neovascularization . AlthougSeveral imaging biomarkers have been identified for carotid plaque instability including intraplaque hemorrhage, neovascularization, plaque rupture, lipid-rich necrotic core, and fibrous cap thickness.The clinical relevance of these imaging biomarkers lies in their ability to predict stroke risk and guide treatment decisions. Identifying vulnerable plaques with imaging biomarkers can aid in the selection of patients who may benefit from carotid endarterectomy or stenting. Additionally, monitoring changes in imaging biomarkers over time can help to assess the effectiveness of medical therapy or lifestyle modifications aimed at reducing stroke risk.These biomarkers can be assessed using various non-invasive imaging modalities such as US, CT, MRI, and PET. US is commonly used as the primary imaging modality for initial evaluation, providing valuable information on flow velocity, stenosis severity, and plaque surface and composition. The implementation of 3D US enables the quantification of plaque volume and differentiation between ulceration and gaps within plaques; however, for the more precise assessment of ulceration, CEUS is preferred, which also allows visualization of neovessels. CT imaging is highly effective in accurately detecting calcification, and assessing vessel wall size, plaque burden, and morphological characteristics. MRI has demonstrated clinical significance in detecting IPH with high sensitivity and specificity. Lastly, PET currently stands as the most validated tracer for imaging plaque inflammation. In recent years, technological advancements have greatly contributed to the development of intravascular imaging techniques. The implementation of IVUS, OCT, and NIRS in the assessment of carotid plaque instability represents a significant improvement, with OCT showing the potential to achieve results comparable to those obtained through histological biopsy. However, considering their invasive approach, the use of these techniques in assessing risk in asymptomatic patients is highly debatable.Incorporating a synergistic approach involving multiple imaging modalities is imperative in order to acquire a comprehensive understanding of the features and behavior of unstable plaques, thereby leading to a reduction in the risk of cerebrovascular events.


Porto-mesenteric vein thrombosis (PVT) is a well-recognized but uncommon disease entity in patients with and without cirrhosis. Given the complexity of these patients, there are many differing treatment algorithms depending on the individual circumstances of a given patient. The focus of this review is primarily patients with cirrhosis, with an emphasis on liver transplantation considerations. The presence of cirrhosis substantially affects work-up, prognosis, and management of these patients and will substantially affect the patient treatment and have additional implications for prognosis and long-term outcomes. Here, we review the incidence of portal vein thrombosis in known cirrhotic patients, medical and interventional treatment options that are currently used, and, in particular, how to approach cirrhotic patients with PVT who are awaiting liver transplantation. Porto-mesenteric vein thrombosis (PVT) is a well-recognized, albeit uncommon disease entity in patients with and without cirrhosis ,2,3,4,5.The risk of portal vein thrombosis in patients with cirrhosis is estimated to be approximately 10% in patients with compensated cirrhosis, with increasing prevalence in more advanced stages of cirrhosis. The rate of PVT is as high as 26% in decompensated liver transplant candidates ,8,9. TheThe presence of HCC is also associated with development of PVT, not only due to direct vascular invasion (tumor thrombus), but also related to the prothrombotic nature of cancers, including HCC, in general with patients expressing thrombophilic genetic factors at higher risk than those without ,13. It iLiver transplantation is a mainstay treatment for patients with decompensated liver cirrhosis and other liver conditions with high mortality rates. At five years, post-transplantation survival rates can exceed 75% in well-selected patients . EarlierPortal vein thrombosis impacts liver transplant outcomes in several ways. First, the presence of acute or chronic portal vein thrombosis  reduces The impact of portal vein thrombosis on liver transplantation has not been fully appreciated, given that until recently PVT was a contraindication or relative contraindication to liver transplantation, and data on non-listed patients were incomplete. Determining the impact of portal vein thrombosis in liver transplantation is further complicated by the fact that until recently, pre-operative incidence of PVT in patients ultimately not listed for transplant has not been well-documented. In fact, one review estimated that the true incidence of portal vein thrombosis amongst liver transplant candidates may be as high as 44% . FurtherAnticoagulation remains a mainstay of PVT treatment, with studies suggesting that anticoagulation treatment prevents thrombus progression, can result in thrombus improvement, decreases variceal bleeding, and improves ascites . CurrentAchieving a physiologic portal vein-to-portal vein anastomosis is the optimal surgical outcome during liver transplant, which results in similar overall outcomes between patients with PVT and those without . The keyTo that end, there has been increasing focus on alternative surgical management strategies that focus on the restoration of physiologic portal flow even in the absence of a portal end–end anastomosis defined as restoring splanchnic blood flow to the liver graft in order to relieve the effects of portal hypertension . CurrentThere have been multiple classification schemes  devised In light of the suboptimal results of anticoagulation alone as well as the concerns for poor outcomes in transplantation patients, there has been increased interest in endovascular options for portal vein recanalization . While eThere are several described techniques for portal vein recanalization in patients with portal vein thrombosis. For purposes of this review, those interventions specifically relevant to pre-transplantation patients will be described. Pre-procedure assessment and planning. Prior to any procedure, all patients should have an appropriate evaluation by an interventional radiologist, transplant surgeon, and a hepatologist to ensure both adequate transplant candidacy and optimization of liver function and medical therapy prior to proceeding with PVR-TIPS. A decision to proceed should take into account current liver transplant eligibility and listing status (including estimated waiting time in the region), and whether the patient has additional symptoms  that might warrant earlier intervention. All patients should have updated clinical testing, including liver function tests, coagulation assessment, a MELD-Na score, and Child–Pugh scores. In particular, in patients who have more advanced liver dysfunction, including MELD-Na scores > 18–21 or advanced Child–Pugh scores (B or C groups), ensuring that patients are eligible for and/or are actively listed for a liver transplant is important in the event of hepatic decompensation following a procedure. Recent cross-sectional imaging should also be obtained prior to evaluation, with either a contrast-enhanced multiphasic CT or an MRI, to delineate the extent of the thrombosis. Finally, patients receive an echocardiogram to assess cardiac function prior to intervention. At our center, procedures are all performed with general anesthesia and followed by inpatient admission for close post-procedure monitoring. PVR-TIPS techniques: The ability to successfully perform a PVR-TIPS requires mastery of several core building-block techniques that are generally employed in step-wise fashion . First, Initial series described transhepatic access to gain access into the thrombosed portal system; however, more recent series described a higher technical success rate for the procedure with the use of transplenic access into the portal system , which hEarly clinical outcomes of portal vein recanalization for pre-transplantation purposes demonstrate that the procedure is technically safe with the most common complications being TIPS stenosis or medically treatable hepatic encephalopathy . More seGiven the complexities of management of this patient population and the need for input from multiple specialties, our center has instituted a formal multidisciplinary splanchnic venous thrombosis program. Prior studies have validated the need for expertise in the interventional management of portal hypertension . The mulNow that recent studies have demonstrated the safety and efficacy of portal vein recanalization techniques in addressing pre-operative acute and chronic portal vein thrombosis, additional questions remain to be answered—specifically, multi-center studies validating early studies are required, standardization of terminology and lexicon, and prospective studies with clear patient selection criteria matched to long-term peri-transplant and post-transplant outcomes. Standardization of techniques  and determination of timing of when to intervene as it relates to this patient cohort are required. Furthermore, understanding how to interleave the use of PVR-TIPS in the broader population of cirrhotic patients with portal vein thrombosis regardless of immediate transplant eligibility will be important given the evolving transplant criteria, the movement of patients across different transplant centers, and the potential for patients with portal vein thrombosis to become transplant-eligible over time. Finally, given the complexities of decision making in this population, formalizing a multidisciplinary approach to care and decision making is essential in the care of these complex patients.