Setaria viridis, Stipa bungeana, and Bothriochloa ischaemum) in monoculture and all possible two- and three-way combinations, along with a plant-free control pot. The plants were harvested after about 4 months, and the rhizospheric soil was collected. The bacterial communities of the soils were analyzed by high-throughput sequencing of the 16S rRNA gene. Plant competition affected richness of bacterial communities. Proteobacteria and Bacteroidetes were generally higher and Actinobacteria and Acidobacteria were lower in relative abundance in the mixed treatments associated with B. ischaemum. Photosynthetic bacterium, Genus Rhodobacter family Rhodospirillaceae, affected the growth condition and increased the competitive ability of B. ischaemum. Differences in the amounts of soil organic carbon, water-soluble organic carbon and nitrate nitrogen and available phosphorus drove the differences in bacterial communities. Our study has an important significance for understanding the trend of natural succession on the abandoned farmland on the Loess Plateau of China.Interactions between plant and soil communities have important implication for plant competition, development and succession. In order to explore the internal mechanism behind natural succession of abandoned farmland, we test the effect of plant–soil interaction on plant growth and competitive ability through performing a pot experiment, which included three grasses in different successional stages on the Loess Plateau of China ( Plants supply litter, decomposing roots and exudates that provide distinct combinations of substrates to unique soil microbial and macro-invertebrate communities, and the soil community in turn influence nutrient cycling, plant nutrient availability, disease protection, plant health, and plant growth . The intThe most pronounced effects of plant on soil microbial community was observed in the zone directly adjacent to active plant roots, i.e., the rhizosphere . The rhiPlant succession is often associated with plant competition, changes of plant species, plant diversity, and plant community composition, and have been shown to influence rhizospheric microbial communities . van de Setaria viridis, Stipa bungeana, and Bothriochloa ischaemum, were selected, which are typical native herbaceous species widely distributed on the Loess Plateau of China . This area has a warm continental monsoon climate with hot and wet summers and cold and dry winters. The mean annual temperature is 13.0°C, with maximum and minimum mean monthly temperatures of 26.7°C in July and -1 to -2°C in January. The mean annual precipitation is about 632 mm, which occurs mainly from July to September .S. viridis, S. bungeana, and B. ischaemum, were selected for this study. All are typical native herbaceous grasses widely distributed on the Loess Plateau of China  of the Institute of Soil and Water Conservation on the plateau.Three gramineous plants, of China . S. viri-1 soil organic carbon (SOC), 0.22 g kg-1 total nitrogen (TN), 0.55g kg-1 total phosphorous (TP) and 3.04 mg kg-1 available phosphorous (AP). The soil was added to cylindrical polyvinyl chloride (PVC) pots . The bottom of each pot was covered with about 1 kg of stones (diameter: 1 cm). A plastic tube  used for irrigation was placed vertically immediately above the stones. Filter paper was then placed over the stones and around the plastic tube. The pot was then filled with about 3.8 kg of sieved (5 mm) and air-dried loess.We used loessial soil  collected from farmland at the Ansai Research Station. The field capacity of the loess, determined as gravimetric soil-moisture content, was about 20%. The soil at the beginning of the experiment had a pH of 8.68 and contained 1.71g kgS. viridis, S. bungeana, and B. ischaemum as monocultures , all pair-wise combinations of these three species , all species mixed (GCB) and pots without plants as a control (CK). Each treatment had five replicates, for a total of 40 pots. The planted pots were sown with multiple seeds on 22 April 2015, in order to simulate the field condition, the plants were thinned to six S. bungeana and B. ischaemum and twelve S. viridis in the monocultures; three S. bungeana, three B. ischaemum or six S. viridis in the pair-wise combinations and two S. bungeana and B. ischaemum and four S. viridis in GCB to simulate natural proportions. The pot size and planting pattern were shown in Figure 1. We watered all pots with distilled water to maintain near 80% field capacity by weighting method until the end of the experiment, in order to minimize the effect of moisture on plant and microbial community. The plants grew normally in outdoor conditions under a rain shelter (height 3 m) to prevent the addition of rainwater. Pot positions were changed once a week to reduce any micro-environmental effects.We tested eight treatments: Three of the five replicates were randomly selected for sampling 117 days after sowing. Above- and belowground tissues were harvested separately. The roots of the competing plant species tended to become entangled, so we collected all roots together. Loosely adhering soil was removed by shaking and was discarded, and the remaining soil strongly adhering to the roots was considered the rhizosphere and was brushed from the entire root system for collection. The above- and belowground tissues were carefully washed with distilled water and were then oven-dried at 80°C for 48 h for determining their biomass dry weights. Visible plant roots and debris were removed from each soil sample, which was then divided into three parts. One part was immediately stored at -80°C for DNA analysis, the second part was immediately sieved through a 2-mm mesh and stored at 4°C for the analysis of water-soluble organic carbon (WSOC) and the third part was air-dried for physicochemical analysis.4+-N) and nitrate nitrogen (NO3--N) were extracted from 2.5 g of soil incubated in 25 ml 1 M KCl for 1 h and analyzed calorimetrically on an Alpkem Autoanalyzer . TP content was determined by melt-molybdenum, antimony and scandium colorimetry  following the manufacturer’s recommendations, and index codes were added. The quality of the libraries was assessed using a Qubit@ 2.0 Fluorometer (Thermo Scientific) and an Agilent Bioanalyzer 2100 system. The libraries were then sequenced on an Illumina HiSeq 2500 platform, generating 250-bp paired-end reads.DNA was extracted from 0.25 g of soil using a TIANamp Soil DNA Kit . The DNA extracts were diluted 10-fold and spectrophotometrically assessed for quality and quantity . The integrity of the DNA extracts was confirmed by 1% agarose gel electrophoresis. DNA was amplified by PCR in triplicate using primers for the 16S rRNA gene. The 341F (5′ - CCTAYGGGRBGCASCAG - 3′) and 806R (5′ - GGACTACNNGGGTATCTAAT - 3′) primers were designed to amplify the hypervariable V3+V4 region of bacterial 16S rRNA genes. The primers were tagged with unique barcodes for each sample. PCR reactions were performed in a volume of 30 μl containing 2 μl of sterile ultrapure water, 15 μl of Phusion Master Mix (2X), 3 μl of 6 μM primers and 10 μl of template DNA (5–10 ng). The PCR program was: 98°C for 60 s; 30 cycles of 98°C for 10 s, 50°C for 30 s and 72°C for 30 s; 72°C for 5 min and hold at 4°C. Sterile ultrapure water was used as negative controls for detecting primer or DNA contamination. Successful PCR amplification was verified by 2% agarose gel electrophoresis. The triplicate PCR products were mixed in equidensity ratios and were then purified using a Qiagen Gel Extraction Kit . Sequencing libraries were generated using a TruSeq1 using the UCHIME algorithm  workflow . In brielgorithm  to deteclgorithm  and assilgorithm . Taxonomlgorithm  using thlgorithm  algorithRYT) was defined and developed by RYT values are calculated by the following expression:The relative yield total  was propose by The competitive ratio . iP and jP are the proportion of i and j was sown, respectively. ijCR> 1 means the competitive ability of i is greater than that of j; ijCR < 1 means i is less competitive than j.where, means of P < 0.05. The Shannon and Simpson indices were calculated to assess microbial diversity, and Chao1 and ACE were calculated to estimate species richness. Principal coordinates analysis (PCoA) was used to evaluate the overall differences in the structures of the microbial communities based on Unweighted Unifrac distances. A canonical correspondence analysis (CCA) with forward selection and 999 Monte Carlo simulations was used to identify soil chemical properties that significantly explained the variance of the microbial groups (P < 0.05). Structural equation modeling (SEM) was used to gain a mechanistic understanding of the effect of the plant and soil properties on rhizospheric bacterial composition and richness. The structures of the bacterial communities were assessed by the first principal components of the PCoA. We chose to use root biomass as the original causal factor, because the effects of roots on a rhizosphere, such as exudates and root death, are likely the most important influences on the rhizospheric chemical properties and microbial communities  and a low root mean squared error of approximation . According to formulas (1) and (2), the RYT in mixture treatments Setaria viridis + Stipa bungeana, Stipa bungeana + Bothriochloa ischaemum, and Stipa bungeana + Bothriochloa ischaemum were greater than 1, but the competitive ratios (CRs) in mixture treatments were less than 1 (Table 2).The species had different biomasses, and increasing the number of species had only occasional additive effects on biomass. Aboveground and total biomasses were the highest in the B treatment, but belowground biomass followed the order B > CB, GB and GCB > G, C and GC .Soil organic carbon and WSOC contents were higher in the planted treatments than CK, but the mixed treatments almost showed non-additive effect compared to the monocultured treatments. Trends were opposite between AP and NOTable 4). The rarefaction curves for the OTUs, Shannon index and Chao1 reached an asymptote , indicating that current numbers of sequence reads were sufficient to capture the bacterial diversity in these soils.High-throughput sequencing produced a total of 1,436,760 high-quality sequences and a total of 64,218 OTUs with 1,934-3,001 OTUs per sample after removing low-quality reads and chimeras and trimming the primers and barcodes. The Good’s coverage values had a range of 0.981–0.986 at 97% similarity cutoff (Table 5).Microbial richness (Chao1 and ACE) and number of OTUs were significantly higher only in GCB treatment compared to CK. Neither plant species nor plant competition significantly affected microbial diversity (Shannon and Simpson indices) . The dominant phyla were Proteobacteria (average 50.82%), Actinobacteria (15.36%), Acidobacteria (8.29%), Bacteroidetes (4.91%), Gemmatimona-detes (4.15%), Verrucomicrobia (2.29%), and Chloroflexi (2.78%). Effects of plant competition on bacterial composition was stronger than plant species. The relative abundance of Proteobacteria were significantly higher in CB, GB, and GCB treatments than in G, C, and CK treatments, and relative abundance of Bacteroidetes was much higher in mixed treatments than in monocultured and CK treatments. By contrast, the relative abundance of Actinobacteria in B, CB, and GB was significantly lower than CK treatment, and the relative abundance of Acidobacteria was lower in the mixed than in the monocultured and CK treatments. The abundances of the other phyla just differed occasionally among treatments .The rhizospheric bacterial taxa differed among various competi-tive treatments .The classes Rhodospirillales, Rhizobiales, Burkholderiales, Acidimicrobiales, iii1-15, and Cytophagales showed remarkable difference among treatments. Rhodospirillales, Rhizobiales, Burkholderiales, and Cytophagales generally had higher relative abundances in CB, GB, and GCB treatments than the monocultured treatments and CK, whearas Acidimicrobiales and iii1-15 showed the opposite pattern . At the family level, Rhodospirillaceae, Comamonadaceae, and Cytophagaceae had generally higher relative abundance in CB, GB, and GCB treatments compared to monocultured and CK treatments, and relative abundance of Sphingomonadaceae was higher in mixed treatments than in monocultured treatments . All of dominant genuses displayed in Figure 3E showed similar trends, especially Methylibium, Novosphingobium, and Sphingomonas, relative abundance of which were higher in CB, GB, and GCB treatments than in monocultured and CK treatments.Dominant orders of Figure 4).The PCoA clustered the bacterial communities into three distinct groups: the monocultured treatments, the mixed treatments and CK. Bacterial communities from the same planting pattern tended to group together, and showed strong clustering between samples from similar planting patterns . SOC, WSOC, NO3--N and AP contents were the most influential factors driving the differences in community structure (Table 3). The vectors on the CCA ordination plot generally suggested that most subgroups of Proteobacteria were positively correlated with carbon contents, and the dominant subgroups of Actinobacteria and Acidobacteria were opposite. Sphingomonadales, Xanthomonadales, and Cytophagales was positively correlated with NO3--N and AP contents.The CCA analysis indicated that the first two canonical axes explained a total of 60.49% of the total variance, with the first and second axes explaining 49.09 and 10.59%, respectively  and accounted for 45, 15, 34, and 15% of the variability in SOC, WSOC, NO3--N and AP contents, respectively . Belowground dry weight showed positive effect on SOC, WSOC, NO3--N contents and negatively affected AP content. Change of bacterial structure were resulted from the direct and positive effects of SOC, WSOC, NO3--N, and AP content, and change of bacterial richness was resulted from the positive effect of SOC, WSOC, and AP contents and negative effect of NO3--N content.The soil-nutrient indices used in the SEM was selected based on the CCA analysis and identified large influences on the rhizospheric bacterial communities. The SEM model fit the data well . It is widely acknowledge that plants produce different amounts and compositions of carbon resources , which was in agreement with previous studies . The nutrient content was lower and nutrient availability was poorer in our study compared to soil that has been restored for many years , indicating that two components almost did not compete and show full resource complementarity. The competitive ratio (CR) gives the exact degree of competition by indicating the number of times one component is more competitive than the other , and treatments of B, CB, GB, and GCB have apparently higher abundance of family Rhodospirillaceae, and treatments of B, GB, and GCB have obviously higher abundance of genus Rhodobacter . Our results indicated that B. ischaemum tended to grow better when lived together with other species, and the unique bacterial communities associated with B. ischaemum facilitated the improvement of competitive ability. Genus Rhodobacter family Rhodospirillaceae  are photosynthetic bacterium and have exuberant vitality, which can grow photoheterotrophically under anoxic conditions in the light, chemoheterotrophically in the dark, or heterotrophically under aerobic/microaerobic conditions (Rhodobacter can encode proteins involved in numerous energy-generating and energy-utilizing processes, such as photosynthesis, carbon fixation, nitrogen fixation, hydrogen utilization, aerobic and anaerobic respiration, denitrification, electron transport and aerotaxis (B. ischaemum outcompete other grass species and become the dominant species in the late natural succession stage was attributed to not only the strong competitiveness and adaptiveness but also the function of photosynthetic bacterium cultivated by itself.Rhizospheric bacterial community imposed an effect on plant growth and competition. As we see, the biomass of nditions . Due to erotaxis , the groProteobacteria, Actinobacteria, Acidobacteria and Bacteroidetes were greatly affected by some soil properties. Results of CCA variance partitioning of environmental factors to the microbial communities indicated that SOC, WSOC, NO3--N and AP contents were important driving factors for the formation and transformation of the rhizospheric communities. The SEM model supported the CCA result and indicated that grass competition accounted for 45, 15, 34, and 15% of the variability in SOC, WSOC, NO3--N and AP contents, respectively. Furthermore, SOC, WSOC, NO3--N, and AP contents together explained 80% of the variability of bacterial structure and 45% of the variability of bacterial richness. Belowground dry weight showed positive effect on SOC, WSOC, NO3--N contents and negatively affected AP content. Change of bacterial structure was thus mainly resulted from the direct and positive effects of SOC, WSOC, NO3--N, and AP content, and change of bacterial richness was resulted from the positive effect of SOC, WSOC, and AP contents and negative effect of NO3--N content.The CCA indicated that the abundances of the dominant sub-groups of Proteobacteria sub-groups were positively correlated with factors associated with carbon, and the dominant subgroups of Actinobacteria and Acidobacteria was opposite, suggesting that most members of this phylum were sensitive to the differences in soil carbon. The presence of grass on bare land will provide organic carbon and nitrogen to decomposer organisms in the form of rhizodeposition and dead biomass, which will subsequently favor copiotrophic groups such as Proteobacteria (Actinobacteria and Acidobacteria (Sphingomonadales, Xanthomonadales, and Cytophagales was positively correlated with NO3--N and AP contents. This result suggested that NO3--N and AP contents also plays an important role in the formation of rhizospheric bacterial communities, and 4+-N, TN, and TP contents and pH value. These indices did not differ significantly after the 4-month pot experiment and remained within a narrow range, which may have been responsible for the weak correlations.Most of the bacteria , and defbacteria , 2012. IB. ischaemum increased the relative abundance of Proteobacteria and Bacteroidetes and decreased the relative abundance of Actinobacteria and Acidobacteria. In turn, photosynthetic bacterium, Genus Rhodobacter family Rhodospirillaceae, affected the growth condition and contributed to increased the competitive ability of B. ischaemum. In addition, plant composition caused the difference of SOC, WSOC, NO3--N and AP contents, which explained most of the differences in the rhizospheric bacterial communities. Therefore, this interaction between plant composition and soil was in part responsible for plant competitive result and may be the key driving factor to impact and change the trend of vegetation succession on the Loess Plateau of China.Interactions between plant and soil communities existed in a short-term competitive experiment. Mixture treatments associated with CS, SX, and GL initiated and designed the research, collected the materials, and performed the experiments. SX and GL obtained funding for this study. CS analyzed the data and wrote the manuscript. All authors read and approved the manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer GY declared a shared affiliation, with no collaboration, with the authors to the handling Editor at time of review.


Vena cava thrombus is one of the main clinical manifestations of locally aggressive renal cell carcinoma (RCC). Inferior vena cava (IVC) wall invasion and presence of bland thrombus could affect the surgical outcome. This study aims to assess the value of contrast-enhanced ultrasound (CEUS) in detecting wall invasion and differentiating bland thrombus from tumor thrombus during robot-assisted IVC thrombectomy for RCC.The intraoperative CEUS findings of 60 patients with RCC accompanied by IVC tumor thrombus were retrospectively analyzed. The CEUS features were compared with the intra- and post-operative pathological findings. CEUS in patients with wall invasion showed that the tumor thrombus was enhanced synchronously with the IVC wall, and the continuity of the IVC wall was lost. In contrast, in patients without wall invasion, CEUS showed that the contrast agent could pass between the tumor thrombus and the IVC wall, and the continuity of IVC wall was good. Typically, contrast-enhanced perfusion was seen in tumor thrombus but not in bland thrombus. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CEUS were statistically analyzed.The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the typical enhancement mode of CEUS were 93.1, 93.5, 93.3, 93.1, and 93.5% in identifying wall invasion and 100, 96, 96.7, 83.3, and 100% in differentiating bland thrombus from tumor thrombus, respectively. There were excellent inter-observer agreements for identifying IVC wall invasion and differentiating bland thrombus from tumor thrombus with kappa coefficients of 0.90 and 0.97.The present study indicates that intraoperative CEUS plays an important role in robot-assisted IVC thrombectomy for RCC. It can detect wall invasion and differentiate bland thrombus from tumor thrombus, thus offering real-time information to the operator during surgery. Vena cava thrombus is one of the main clinical manifestations of locally aggressive renal cell carcinoma (RCC). Approximately 4–10% of locally aggressive RCC cases presented with inferior vena cava (IVC) tumor thrombus , 3. The Therefore, how to judge the wall invasion and the presence of bland thrombus by imaging examinations for surgical strategy development has become a hot research topic. Although some CT and MRI studies have been carried out in this field –16, thesThe purpose of this study was to investigate the diagnostic performance of intra-operative CEUS in detecting wall invasion and differentiating bland from tumor thrombus of IVC in patients with RCC undergoing nephrectomy in comparison with intra-operative and post-operative pathological findings.This retrospective study was approved by the Institutional Review Board of the Chinese PLA General Hospital . Informed consent was signed by all patients. We retrospectively analyzed the data of 60 patients with RCC with IVC tumor thrombus who were treated in our hospital between October 2017 and March 2019. These patients included 46 males and 14 females, aged 30–81 years, with a median age of 54.6 years. Renal tumors were located on the left side in 22 cases and on the right side in 38 cases  was used. SonoVue is based on stabilized sulphur hexafluoride microbubbles with a mean size of 2.5 μm  was identified; sector scan was performed with this area as a center and a dynamic scan was also performed around the lesion. After the CEUS mode was turned on, 5 ml SonoVue contrast agent was injected via peripheral vein pellet, followed by rapid injection of 5 ml saline. The results were observed for 3 min and the whole CEUS process was recorded and saved.Two ultrasonographists with more than 3 years of experience in CEUS-based diagnosis who were blind to any preoperative imaging and clinical data of the patients were asked to read the CEUS images.Before image reading, both Reader 1 and Reader 2 received training on reading sample CEUS images of tumor thrombus intra-operatively obtained from 10 patients, who were not included in the final study group. They were required to independently read the images of these 60 patients to determine the presence (or absence) of wall invasion and bland thrombus.Tumor thrombus does not invade the IVC wall: a) strip-like contrast media can be seen between the tumor thrombus and the IVC wall; and b) the IVC wall continuity is maintained. Tumor thrombus invades the IVC wall: a) the tumor thrombus is enhanced synchronously with the IVC wall; and b) the IVC wall continuity is lost.Tumor thrombus, contrast agent perfusion can be seen in the IVC thrombus. Bland thrombus, no contrast agent is perfused into the IVC thrombus.According to the results of intra-operative CEUS, Reader 1 and Reader 2 independently read and judged wall invasion and bland thrombus according to the image characteristics. A third senior ultrasonographist was consulted when the results were inconsistent.During surgery, wall invasion was diagnosed if the tumor thrombus could not be dissected easily and vice versa. All the pathological results were obtained within 7 days after the examinations. Pathological sections were read by the same pathologist.t test, and a P value of less than 0.05 was considered statistically significant. The results of diagnostic tests are expressed by sensitivity, specificity, accuracy, positive predictive value, and negative predictive value. Cohen’s kappa coefficient was used to measure the inter-observer agreement for categorical variables.Statistical analysis was performed using SPSS 13.0 software. The maximum diameters of tumor thrombus measured by intra-operative ultrasound are presented as mean ± standard deviations. Measurement data between groups were compared using All 60 patients with IVC tumor thrombus underwent robot-assisted laparoscopic radical nephrectomy plus IVC thrombectomy, including open IVC thrombectomy in 51 patients, and IVC resection in 9 patients. All the procedures were successfully performed. CEUS images were acquired successfully without any adverse events. According to the clinical and pathological results, wall invasion was found in 29 patients, in whom CEUS showed that the tumor thrombus was enhanced synchronously with the IVC wall, and the continuity of the IVC wall was lost Fig. , Table 3The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of intra-operative CEUS were 93.1, 93.5, 93.3, 93.1 and 93.5%, respectively, in the diagnosis of wall invasion Table  and 100,Of the 50 patients undergoing preoperative enhanced MRI examinations within 10 days before surgery, contact of the IVC thrombus to or rupture of the vessel wall were defined as wall invasion. The tumor thrombus was enhanced and the bland thrombus was not enhanced. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of preoperative enhanced MRI were 92.3, 91.7, 92, 92.3 and 91.7%, respectively, in the diagnosis of wall invasion and 75, 95.2, 92, 75 and 95.2%, respectively, in the diagnosis of bland thrombus Table . In 2 caP<0.05), suggesting that the risk of wall invasion increased with the increase of the anterior-posterior diameter of tumor thrombus. In two patients with wall invasion confirmed by intra- and post-operative pathology, CEUS did not detect the synchronous enhancement of the tumor thrombus and the IVC wall due to lack of blood flow signals in tumor thrombus, resulting in misdiagnoses. In another two cases, a diagnosis of wall invasion was made, but post-operative pathology showed that the tumor thrombus did not invade the IVC wall. In fact, the anterior-posterior diameter of tumor thrombus in these two cases was 42.78 mm and 44.23 mm, respectively. The tumor thrombus grew in an expansive way, and they squeezed but did not invade the IVC wall. The IVC wall became thinner due to the compression, which led to the misdiagnosis by intra-operative CEUS.The maximum anterior-posterior diameter of the tumor thrombus was 40.12 mm ± 7.32 mm in the wall invasion group and 32.10 mm ± 6.12 mm in the non-invasion group, with significant difference  of the blood supply of tumor thrombus, the route of blood supply, the synchronous enhancement of the tumor thrombus, and even the inferable composition of tumor thrombus. On one hand, when the tumor thrombus invades the IVC wall, the venous wall will be enhanced synchronously with the tumor thrombus on CEUS. If the tumor thrombus does not invade the IVC wall, the passing of contrast agent between the cancer thrombus and the venous wall can be clearly visualized due to the high sensitivity of CEUS in detecting blood flow. On the other hand, the composition and blood supply characteristics of the tumor thrombus are completely different from those of the bland thrombus in IVC, which provides a basis for differentiating these two thrombus by CEUS. The components of IVC bland thrombus include platelets, white blood cells, red blood cells, and cellulose. As there is neither active substance nor blood supply, the IVC tumor thrombus is not enhanced on CEUS.As shown in the present study, intra-operative CEUS could sensitively reflect the blood perfusion of IVC thrombus, the wall invasion by tumor thrombus, and the presence of bland thrombus. Its high resolution allows the operator to learn the blood supply of tumor thrombus in a real-time and intuitively manner, which reminds the doctor to take corresponding measures timely to ensure a successful operation.Our study had some limitations. First, as a retrospective study, it might have potential selection bias; second, this is a single-center study with a relatively small sample size.This study indicates that CEUS in robot-assisted IVC thrombectomy can detect wall invasion and differentiate bland thrombus from tumor thrombus, thus offering real-time information to the operator during surgery for RCC.


IntroductionMortality from sepsis is decreasing in recent years owing to improved quality of care, targeted programs, and the implementation of sepsis bundles. This has led to an increased pool of sepsis survivors at risk of readmissions. Studies have shown that these sepsis readmissions are common and expensive. The factors associated with these readmissions remain elusive and have incited a lot of research in recent years. The 30-day sepsis readmission rate is increasingly being used as a quality metric for hospitals. A conducted a retrospective chart review analysis of patients admitted with sepsis to find factors affecting the 30-day readmissions of sepsis survivors.MethodsPatients admitted to our hospital either on the medical-surgical floor or in the intensive care unit (ICU) with an administrative coding for sepsis between January 2014 to November 2015 were identified. A literature search, as well as expert opinion, was considered for the list of factors to be studied, including age, sex, residence on admission, length of stay, getting hemodialysis, hospitalization in the prior year, presence of acute kidney injury (AKI), source of sepsis, discharge disposition, receipt of red blood cell (RBC) products, and route of antibiotics on discharge. A univariate binary logistic regression analysis was performed to test the association between the above-mentioned variables and sepsis readmission. Variables with statistical significance in the univariate analysis were used to compute the multivariate regression analysis along, with adjusted OR and their 95% CI.ResultsA total of 1297 patients were identified with sepsis. Of these, 1068 patients met inclusion criteria. The readmission rate in our study population was 19.19%, and 52% of the readmissions were secondary to an infectious cause. After controlling for the effect of all the potential confounders, the factors that showed a positive association with readmissions were hospitalizations in the year prior to the index hospitalization and discharge to either nursing home or short-term rehab. The requirement of the intensive care unit was not associated with increased readmission. High hemoglobin on discharge was associated with a reduced chance of readmission.ConclusionsReadmissions after sepsis hospitalization are common and mostly caused by infections. Several factors associated with index sepsis hospitalization can be associated with readmissions. Some of these factors are modifiable and more research is needed to see if these readmissions can be prevented. Sepsis continues to be a major public health problem in the United States. It is one of the most common causes of hospital admissions, accounting for a major portion of the healthcare expenditure of the country. According to Angus et al., severe sepsis accounted for over 750,000 hospital admissions in 1995, of which 383,000 received intensive care. Since then, various analyses have shown an increasing incidence of sepsis in the US population .Over the last several decades, significant progress in understanding the sepsis pathophysiology, earlier recognition, and goal-directed therapies have led to improved outcomes in terms of sepsis mortality and increased number of sepsis survivors -4.These sepsis survivors are often left with significant cognitive and physical disabilities, decreased quality of life, and increased morbidity, leading to an ongoing and long-term requirement for acute care. This causes a significant burden on the health care system -7.Sepsis is one of the top 10 reasons for hospitalization in the United States and is increasingly becoming a common reason for readmissions -9. The UIn recent years, many studies have established increased readmission rates among patients admitted and treated for sepsis -13. HoweTo identify some of the missing links, we conducted a retrospective study on patients admitted with sepsis at a community hospital, to identify factors associated with 30-day readmissions. In addition, we hypothesized that patients admitted to the intensive care unit would pose an increased risk of readmissions.Study designWe performed a retrospective cohort study of adults hospitalized with sepsis or severe sepsis at Saint Vincent Hospital, Worcester - a community-based hospital - from January 2014 to November 2015. MetroWest Medical Center Institutional Review Board approved the study with an informed consent exemption.OutcomesThe primary objective of the study was to determine the rate of 30-day readmissions in patients surviving sepsis in our hospital. The secondary objective was to identify the index hospitalization factors associated with readmission in sepsis patients.Data collectionAdult patients (age>18) who were hospitalized with sepsis and severe sepsis were included in the study. Both medical and surgical patients were included in the study. Patients who were pregnant, discharged within 24 hours, died during the index hospitalization, transitioned to hospice, or transferred to an outside hospital were excluded from the study. A list of study patients was identified using the International Classification of Diseases, ninth revision, Clinical Modification (ICD-9-CM) codes. The diagnosis was confirmed by a chart review in the electronic medical record (EMR). The international consensus conference definition was used to define sepsis.SepsisTwo or more of the following conditions, along with a suspected or confirmed source of infection:2 <32 mmHg; 4) white blood cell (WBC) >12,000/cu mm, <4,000/cu mm, or >10% immature (band) forms.1) Temperature >38°C or <36°C; 2) Heart rate >90 beats per minute; 3) Respiratory rate >20 breaths per minute or PaCOSevere SepsisSepsis associated with organ dysfunction, hypoperfusion, or hypotension. Hypoperfusion may include but is not limited to lactic acidosis, oliguria, or change in mental status.Septic ShockSepsis-induced hypotension despite adequate fluid resuscitation requiring the use of inotropic or vasopressor agents.The survivor cohort was analyzed for 30 days after the discharge. For each index hospitalization, patient-level characteristics  and hospitalization data, including length of stay, source of infection, red blood cell transfusion, hemoglobin level, white blood cell (WBC) count, presence of renal failure, requirement of hemodialysis, discharge disposition, source of infection, route of antibiotics at discharge, and cause of readmission were collected. These factors were derived based on the combination of a review of previous positive and negative studies and expert opinion.Statistical analysisReadmission was considered as the outcome variable. Age, gender, residence at admission, length of stay, hemodialysis, prior hospitalization in one year, peak WBC, presence of AKI, source of infection, discharge disposition, ICU requirement, cause of readmission, duration of antibiotics, discharge hemoglobin, Clostridium difficile infection, red blood cell (RBC) transfusions, and antibiotics at discharge were considered explanatory variables.A descriptive analysis was carried out by the mean and standard deviation for quantitative variables and by the frequency and proportion for categorical variables.A univariate binary logistic regression analysis was performed to test the association between the explanatory variables and the outcome variables. The unadjusted odds ratio along with 95% CI are presented. Variables with a statistical significance in the univariate analysis were used to compute the multivariate regression analysis. The adjusted odds ratio along with the 95% CI are presented.p-value <0.05 was considered statistically significant. IBM SPSS version 22  was used for the statistical analysis.EnrollmentThere were 1297 patients admitted with sepsis during our study period. A total of 157 patients died during the index hospitalization, and 72 either left against medical advice, transferred to another hospital, or transitioned to hospice, and thus were not considered for the analysis. A total of 1068 subjects were included in the final analysis. Of the 1068 subjects at risk for readmissions, 280 were admitted in the ICU and the remaining 788 were admitted on the medical-surgical floor.The baseline characteristics at index hospitalization are given in Table Among the total study population (1068), males aged >65 years formed a greater proportion. Four-hundred eighty (44.94%) participants were aged ≤65 years and 588 (55.06%) participants were aged >65 years; 567 (53.09%) participants were male while the remaining 501 (46.91%) participants were female. The majority of the participants presented from home, followed by the nursing home and short-term rehab. A large proportion of the patient population (44.85%) had previous hospitalizations in the past one year. The source of sepsis for the majority (45.04%) of the participants was respiratory tract infections, followed by the genito-urinary tract, skin/soft tissue, and gastrointestinal (GI) tract/liver, with 25.37%, 12.55%, and 10.58%, respectively. Bone/joints and blood were 2.25% and 2.15%, respectively. The majority of the patients were discharged home.Hospital readmissionsA total of 205 (19.19%) patients were readmitted within 30 days. Of the 280 ICU patients, 72 (25.71%) patients were readmitted and of the 788 non-ICU patients, 133 (16.88%) patients were readmitted (Table Factors associated with readmissionsThe univariate logistic regression analysis identified associations between primary patient/hospitalization characteristics and 30-day readmissions Table . The mulThe cumulative rate of sepsis readmissions, regardless of the requirement of intensive care in our study, was 19.19%. The readmission rate in subjects requiring intensive care was 25.71%, and in non-ICU subjects, it was noted to be 16.88%. This concludes that readmissions after sepsis hospitalizations are common. Similar readmission rates have been observed in prior studies, but a wide variation exists, likely secondary to the variable case-mix -17. SimiIn our study, the most common cause of readmissions was infectious etiology. This finding is supported by similar studies where the infectious cause appeared to be the cause of readmissions in around 50% of the patients. Gadre et al. found that 42% of the readmissions were due to infectious causes . SimilarWe studied several factors in association with readmissions. We found that, in general, patients with sepsis who presented from nursing homes, hospitalized at least once in the past year, received hemodialysis, had a longer hospital stay, required the intensive care unit, had blood transfusions, or were discharged to either nursing homes or short-term rehabs had incurred higher readmission odds. However, of these factors, only prior hospitalization in one year and discharge disposition to nursing homes were statistically and independently associated with readmissions.Various studies have established that readmission rates vary according to the discharge destination ,17-18. IHigh hemoglobin showed a negative association with readmissions. Some studies have shown that packed RBC transfusion is associated with increased 30-day readmission . HoweverLastly, renal replacement therapy was also associated with an increased risk of readmissions, but the association was not statistically significant. AKI and the requirement of hemodialysis have been shown to be well-associated with high mortality as well as an increased risk of readmissions in septic patients .Our study concludes that readmissions after sepsis hospitalizations are common and mostly due to infectious causes. There are many factors associated with these readmissions, but a wide variation is noted across different studies. Only some of these factors are modifiable and not all hospital admissions are preventable. Some of the factors associated with readmissions are markers of the severity of illness rather than the target of intervention for readmission prevention. Nevertheless, readmissions after sepsis are common, and more research should be done to identify clear targets of intervention.


Supplemental Digital Content is available in the text. Recent clinical trials of new glucose-lowering treatments have drawn attention to the importance of hospitalization for heart failure as a complication of diabetes mellitus. However, the epidemiology is not well described, particularly for type 1 diabetes mellitus. We examined the incidence and case-fatality of heart failure hospitalizations in the entire population aged ≥30 years resident in Scotland during 2004 to 2013.Date and type of diabetes mellitus diagnosis were linked to heart failure hospitalizations and deaths using the national Scottish registers. Incidence rates and case-fatality were estimated in regression models (quasi-Poisson and logistic regression respectively). All estimates are adjusted for age, sex, socioeconomic status, and calendar-year.Over the 10-year period of the study, among 3.25 million people there were 91, 429, 22 959, and 1313 incident heart failure events among those without diabetes mellitus, with type 2, and type 1 diabetes mellitus, respectively. The crude incidence rates of heart failure hospitalization were therefore 2.4, 12.4, and 5.6 per 1000 person-years for these 3 groups. Heart failure hospitalization incidence was higher in people with diabetes mellitus, regardless of type, than in people without. Relative differences were smallest for older men, in whom the difference was nonetheless large . Rates declined similarly, by 0.2% per calendar-year, in people with type 2 diabetes mellitus and without diabetes mellitus. Rates fell faster, however, in those with type 1 diabetes mellitus .Thirty-day case-fatality was similar among people with type 2 diabetes mellitus and without diabetes mellitus, but was higher in type 1 diabetes mellitus for men  and women . Case-fatality declined over time for all groups .Despite falling incidence, particularly in type 1 diabetes mellitus, heart failure remains ≈2-fold higher than in people without diabetes mellitus, with higher case-fatality in those with type 1 diabetes mellitus. These findings support the view that heart failure is an under-recognized and important complication in diabetes mellitus, particularly for type 1 disease. Heart failure incidence has fallen over time for people with and without diabetes mellitus, but is ≈2 times higher in people with diabetes mellitus than people without diabetes mellitus.Heart failure case-fatality is higher in people with type 1 diabetes mellitus.Duration of diabetes mellitus and glycated hemoglobin was associated with increased risk of heart failure in type 1 and type 2 diabetes mellitus.Clinicians should be aware of the importance of heart failure in diabetes mellitus, especially in type 1 diabetes mellitus, where this risk is underappreciated.4 However, little is known about the epidemiology of heart failure in unselected individuals with type 2 diabetes mellitus, and even less about those with type 1 diabetes mellitus.Recent clinical trials of new glucose-lowering treatments have drawn attention to the importance of hospitalization for heart failure as a complication of diabetes mellitus.We have examined the incidence of heart failure for an entire country, and how this has changed over time. All residents in Scotland receive care from the National Health Service (NHS) which is free at the point of contact. All diabetes mellitus–related community (primary care) and hospital outpatient encounters in Scotland are recorded in a centrally-accessible database, and these are linked to national hospitalization and mortality records. Given the prognostic import of developing heart failure, we have also investigated the case-fatality related to incident heart failure hospitalization and how this has changed over time.Specifically, we examined the incidence rate for heart failure hospitalization and 30-day case-fatality after heart failure hospitalization over a 10-year period from January 2004 to December 2013 among people with diabetes mellitus (type 1 and type 2).5 aggregate data are provided in the supplemental appendix (Tables I and II in the online-only Data Supplement), and analysis code has been posted online.6The data, analytic methods, and study materials will not be made available to other researchers for purposes of reproducing the results or replicating the procedure. However, individual-level data are available via application to NHS Information Services Scotland,7 the start of the study period.We used data from the population-based Scottish diabetes mellitus register linked to national hospitalization and death records. The Scottish diabetes mellitus register is derived from primary and secondary care records for people with diabetes mellitus diagnosed in normal clinical practice using blood glucose measurements or hemoglobin A1c with coverage of >99% since 2004,Anyone alive in Scotland aged 30 and older at any time from 2004 to 2013 was included in the analyses.Heart failure was identified from the first mention in any position (primary or secondary diagnoses) in hospital inpatient records using codes from the ninth (ICD-9) and tenth (ICD-10) International Classification of Diseases revisions . Outpatient attendances with heart failure are not recorded in the Scottish national healthcare database, nor in the Scottish diabetes mellitus register.Date and type of diabetes mellitus were obtained from the diabetes mellitus register based on the clinician-recorded date of diagnosis. Diabetes mellitus status was defined as type 2 diabetes mellitus, type 1 diabetes mellitus and no diabetes mellitus.8 SIMD 2009 combines 31 indicators across 7 domains: income, employment, health, education, housing, geographic access, and crime. The index is generated from a weighted sum of the 7 domain scores for each area defined by postcodes (zip codes) which contain a median of 769 people. SIMD data were missing for approximately 1% of hospital admissions or death records, and these records were excluded from the analysis.Age at first heart failure hospitalization and sex were identified from hospital admission and mortality records. Socioeconomic status was assessed via an area-based measure of deprivation which is assigned to residents of Scotland on the basis of where they live using the Scottish Index of Multiple Deprivation (SIMD).As an additional analysis, to explore the association between demographic and clinical risk factors and subsequent risk of heart failure admissions, we also identified a closed cohort from the Scottish Diabetes Register. All patients in this cohort had been diagnosed with type 1 or type 2 diabetes mellitus on or before October 1, 2013 and had not had a heart failure admission in the 10 years before this date. Follow-up data were available for 3 years.9Heart failure in the closed cohort was defined as per the main analysis. However, the clinician-recorded diabetes mellitus type was corrected through the use of additional clinical information  as described in a previous publication.Table III in the online-only Data Supplement) were also obtained, as were data on previous stroke and myocardial infarction within the previous 10 years.For this cohort, baseline characteristics such as glycated hemoglobin, body mass index, duration of diabetes mellitus, blood pressure, and retinopathy were also obtained from the diabetes mellitus register, taking the mean (or mode) of all measures not more than 3 years before the start date. Data on current prescriptions for selected drug classes . As with our previous analyses we used a fixed period to define incident cases to avoid bias from nonobservation of prevalent cases.10 This analysis was replicated using the entire national hospitalization and death record to identify heart failure hospitalizations for the general adult population. Incident hospitalizations were summed by calendar year, age, sex, deprivation decile, and, for the diabetes mellitus dataset, diabetes mellitus type. Within the levels of these stratifying variables, the number of incident heart failure hospitalizations in people without diabetes mellitus was derived by subtracting the diabetes mellitus heart failure hospitalizations from the general population heart failure hospitalizations.Using the population-based Scottish diabetes mellitus register, linked to national hospitalization and death records, heart failure hospitalizations from January 1, 2004  to December 31, 2013 were identified for people with diabetes mellitus aged 20 to 89 years. Heart failure hospitalizations were defined as incident if these were the first to occur on or after January 2004 where no previous heart failure hospitalization had been recorded during the preceding 10 years . This was summed by diabetes mellitus type, calendar-year, age, sex, and deprivation decile. Mid-year population estimates for the general population in Scotland, stratified by age, sex, and deprivation, were obtained from National Records of Scotland. For people without diabetes mellitus, person-time not at risk  was also summed by the same stratifying variables. Within the levels of these stratifying variables, person-time for people with no diabetes mellitus was obtained by subtracting the diabetes mellitus person-time from the midyear estimates population estimates.As for hospitalizations, person-time for people with diabetes mellitus was estimated using the linked diabetes mellitus register, hospitalization, and death data. Each individual’s person-time was estimated as the number of days from the start of the study period  to the date of the incident heart failure hospitalization, death, or censoring at December 31, 2013  and interaction terms to allow for nonlinearity and heterogeneity respectively. We used regression in preference to stratification to avoid categorizing continuous variables, which can result in unstable estimates if a stratum is too small, and loss of information if a stratum is too heterogeneous.Interactions are reported on the same scale as the main effects as the rate ratio (RR) or odds ratio (OR), because this can be interpreted as the relative difference in the magnitude of an association per one-unit change in the interacting variable.P<0.05) were included in the final models. Using the same covariates, generalized linear models with a logit-link and binomial error distribution were used to model both heart failure prevalence and case-fatality.For incidence rates, generalized linear models were used with a log-link and Poisson error distribution, using a scaling factor (quasi-Poisson) to allow for overdispersion. Age in years was divided by 10 so that each increment was a decade . Deprivation deciles were treated as a deprivation score ranging from 1 to 10, which was divided by 5 such that each increment was a 5-point increment. Terms were included for main effects in all models regardless of significance or magnitude of effect. The large and heterogeneous study population with a large number of events allowed us to investigate whether the magnitude of risk associated with diabetes mellitus varied by biologically plausible and clinically relevant variables on the basis of prior knowledge of diabetes mellitus and heart failure. Interaction terms  were retained if the exponentiated coefficient  was ≥1.05 or ≤0.95. However, for interactions with calendar year, all statistically significant interactions , and in separate sensitivity analyses after adding additional ICD-10 codes  for cardiomyopathy, and after restricting the analysis to admissions where heart failure was the primary diagnosis (recorded in the first of 6 possible diagnostic positions).Appendix in the online-only Data Supplement). We fitted models for type 1 and type 2 diabetes mellitus, and a third model which included covariate/diabetes mellitus–type interaction terms to compare risk factor associations between type 1 and type 2 diabetes mellitus. Multiple imputation was used for missing data (Table IV in the online-only Data Supplement).For the analysis of the association between the 3-year risk (odds) of heart failure and clinical and demographic characteristics in the closed cohort, we used logistic regression models. Covariate missingness was addressed using multiple imputation  according to each person’s baseline characteristics. The latter was derived from the model of 3-year risk in the closed cohort described above.SPSS was used to extract the administrative data, and R version 3.4.3  was used for the statistical analyses.Approval for the creation and analysis of the linked dataset containing no person-identifying information was obtained from the Scottish Care Information – Diabetes Collaboration (SCI-DC) steering committee, the Scottish multi-center research ethics committee (reference number 11/AL/0225), the Privacy Advisory Committee of NHS National Services Scotland, and Caldicott guardians.This study included the entire Scottish population who were aged 30 or older at any time between 2004 to 2013. In 2004, this comprised 3 066 253 people without a diagnosis of diabetes mellitus, 136 042 with a diagnosis of type 2 diabetes mellitus, and 18 240 with a diagnosis of type 1 diabetes mellitus. Of these, 1 642 022 (53.6%), 63 086 (46.4%), and 8141 (44.6%), respectively, were women and the mean (and SD) ages were 52.9 (15.3), 65.0 (12.2), and 50.0 (14.1) years, respectively. SIMD was similar across the groups with mean (SD) deprivation scores of 5.5 (2.9), 5.9 (2.8), and 5.6 (2.8), respectively.Figures II and III in the online-only Data Supplement, Table VII in the online-only Data Supplement). Over the 10-year period of the study, among the 3.25 million people remaining there were 91 429, 22 959, and 1313 incident heart failure events  among those without diabetes mellitus, with type 2 diabetes mellitus, and with type 1 diabetes mellitus, respectively.People without diabetes mellitus (n=28 681), with type 2 diabetes mellitus (n=3480), and with type 1 diabetes mellitus (n=382) were excluded because of a previous heart failure hospitalization . For illustration, age-sex stratified rates for 2013 are shown in Table Heart failure incident hospitalization estimated rates from Poisson regression models adjusting for age, sex, and deprivation are shown in Figure Overall, the rate of incident heart failure hospitalization rose steeply with age, was somewhat higher in men than in women, and was higher in individuals with diabetes mellitus than in those without this diagnosis. Incident heart failure hospitalization was also higher in people with type 1 compared with type 2 diabetes mellitus.We found the relative risk of diabetes mellitus–related heart failure hospitalization (as indicated by the rate ratio) was highest in younger people and higher in women than men Figure . HoweverAcross the period studied, the rate of incident heart failure hospitalization fell slightly, at around 0.2% per calendar-year .In models adjusting for age, sex, and deprivation, the rate of decline was slightly steeper in older individuals. The rate of decline was 0.5% per calendar-year faster per 10-year increment in age , and was similar in men and women , and according to deprivation Tables IX and X in the online-only Data Supplement). However, there was some evidence of a more rapid decline in people with type 1 diabetes mellitus, where the decrease was 2.2% per calendar-year faster than in people without diabetes mellitus.From the same model, trends in heart failure incidence rates in people with type 2 diabetes mellitus were similar to those in individuals without diabetes mellitus over a ten-year period from 2004  and 3.55  for 50-year-old women and men, respectively.Over the period of the study, 14.2% (16406/115701) of people admitted to hospital with heart failure died within 30 days of admission.Appendix in the online-only Data Supplement for model coefficients, including interactions). For illustration, age–sex stratified case-fatality is shown in Table Thirty-day case-fatality results obtained from logistic regression models adjusting for age, sex, and deprivation are shown in Figure However, case-fatality was higher among people with type 1 diabetes mellitus compared with people without diabetes mellitus; the difference was larger for men  than for women .Tables XI and XII in the online-only Data Supplement). The rate of decline was around 3.3% per calendar-year  in people without diabetes mellitus. There was no evidence of a steeper decline in people with type 1 diabetes mellitus  or type 2 diabetes mellitus .Trends in case-fatality were also modeled adjusting for age, sex, deprivation, calendar year, and type of diabetes mellitus  were similar to those in the whole cohort , with rates per 1000 person-years (py) of 1.7 (65 657 events/38 117 663.1 py), 9.2 (17 175 events/1 867 390.1 py), and 3.6 (841 events/236 843.7 py) for the no-diabetes mellitus, type 2 diabetes mellitus, and type 1 diabetes mellitus groups, respectively. Nevertheless, the rate ratios for both type 1 and type 2 diabetes mellitus in this group  and 231 (0.9%) for type 2 and type 1 diabetes mellitus, respectively.Age, sex, body mass index, estimated glomerular filtration rate, smoking, previous ischemic heart disease, and stroke all predicted an increased risk of heart failure, although no associations were found for systolic blood pressure, total cholesterol, or HDL cholesterol Table . After aPeople with type 2 diabetes mellitus were more likely than those with type 1 diabetes mellitus to have a current prescription for a range of cardiovascular drugs Table . Across Figures IV and V in the online-only Data Supplement, and Table VII in the online-only Data Supplement) similar associations were found . On adding cardiomyopathy codes  to the heart failure definition used in the main analysis, similar results were also found; this was true for the absolute incident rates and case-fatality, and the rate ratios and odds ratio comparing the 3 groups .On restricting incident heart failure admissions to those where heart failure was the primary diagnosis, the heart failure incidence rates were around half of those reported for any incident admission, with rates per 1000 person-years (py) of 0.9 (34 893 events/38 080 361.9 py), 6.1 (11 551 events/1 885 715.8 py), and 2.7 (635 events/237 683.5 py) for the no-diabetes mellitus, type 2 diabetes mellitus, and type 1 diabetes mellitus groups respectively. Nonetheless, compared with the main analysis  and 1.21 , respectively.We documented the rate of incident heart failure hospitalizations in a large and complete national dataset which included >250 000 people with diabetes mellitus among a population of >3.25 million people aged ≥30 years, in whom there were >115 000 first hospitalizations for heart failure.We examined trends in these rates, and the associated 30-day case-fatality, over a 10-year period (2004–2013). Importantly, we reported these rates and trends separately for people with type 1 and type 2 diabetes mellitus.We found that the age- and sex-adjusted rates of incident heart failure hospitalization were ≈2-fold higher in people with diabetes mellitus, regardless of type, compared with those without diabetes mellitus. In all groups, there was a decline in incidence rate of ≈2% over the decade studied, with a slightly greater rate of decline in people with type 1 diabetes mellitus than in the other groups studied.2In terms of trends, heart failure incident hospitalization appears to be falling more quickly over time  in people with type 1 diabetes mellitus, compared with people with type 2 diabetes mellitus and with people without diabetes mellitus. The difference was moderate; having adjusted for age, sex, and deprivation, the decline was faster in those with type 1 diabetes mellitus (2.1% per year versus 0.2% per year). We are not aware that this finding has been reported previously, but it is consistent with an observation from the Swedish registry that the rate ratio for type 1 diabetes mellitus and incident heart failure was larger in the 1998 to 2004 period than in the 2005 to 2011 period.3 It is important to note, however, that because of the higher overall rates in men and older people, the absolute differences in heart failure incidence were larger in these groups. Therefore, from the perspective of the individual patient, the impact of diabetes mellitus on heart failure risk is greater at older ages and in men. Indeed, the absolute difference in 1-year risk of heart failure admission in 80-year-old men  with and without diabetes mellitus was 2.5%. For the same comparison, but in 40-year-old women, the difference was <0.5%.We also found that the relative difference in heart failure incidence between people without diabetes mellitus and those with type 1 or type 2 diabetes mellitus was larger for younger people and for women than for older people and men. This is consistent with previous reports.Unlike incidence, for case-fatality the relationship with diabetes mellitus depended on the type of diabetes mellitus. Case-fatality was similar among people with type 2 diabetes mellitus compared with those without diabetes mellitus. However, among people with type 1 diabetes mellitus, case-fatality was 1.3-fold higher in women and 1.9-fold higher in men.Women therefore have a 2-fold higher heart failure incidence and a 1.3-fold higher case-fatality. In combination, this means that compared with women without diabetes mellitus, women with type 1 diabetes mellitus have around a 2.5-fold higher risk of having an incident heart failure admission which results in death within 30 days. For the equivalent comparison in men, there is almost a 4-fold difference in risk.3 We obtained a similar relative difference (rate ratio) of 2.12 . For men >60 years of age, the comparable figures were 1.43 and 1.93 , respectively. The fact that we included only hospitalizations, and not primary care attendances, may account for the slightly stronger associations we report.Elevated incidence rates for heart failure admission among people with type 2 diabetes mellitus have been reported previously. One study using the Clinical Practice Research Database (CPRD) used primary care records to define heart failure and type 2 diabetes mellitus. The authors identified 34 198 people with type 2 diabetes mellitus from 1998 to 2010. Among women >60 years of age with and without type 2 diabetes mellitus, they found a relative difference (hazard ratio) of 1.50.1 However, the magnitude of the association in this cohort, which mainly included people with established atherothrombotic disease or risk factors for atherothrombosis, was weaker than we found at 1.33-fold. In sensitivity analyses excluding any patient with a previous ischemic heart disease admission, we continued to observe an ≈2-fold association. However, we did not have any measures of stable coronary disease. As such, one explanation for the stronger association we observed is that the increased heart failure risk in diabetes mellitus is partly related explained through increased risk of atheromatous disease.In the international Reduction of Atherothrombosis for Continued Health (REACH) registry, there was also an elevated risk of heart failure hospitalization among the 19 699 people with diabetes mellitus (type unspecified) compared to people without diabetes mellitus.12 Similarly, in a study in the Scottish population comparing incident heart failure admissions from 1986 to 2003, the age–sex adjusted 30-day case-fatality following heart failure admission was lower in people with diabetes mellitus than in those without diabetes mellitus , although case-fatality at 1 year was higher.13 Neither study, however, included data on diabetes mellitus type. Because the majority of people with diabetes mellitus have type 2 diabetes mellitus, these reports are consistent with our own finding that people with type 2 diabetes mellitus did not have a higher case-fatality than individuals without diabetes mellitus.Previous studies examining case-fatality after heart failure admissions among people with type 2 diabetes mellitus have been equivocal. One multi-center register study found no difference in in-hospital mortality among people with diabetes mellitus compared to those without .14 reported a rate of incident heart failure hospitalization of 6.7 per 1000 person-years in people with type 1 diabetes mellitus compared to 4.0 per 1000 person-years in individuals without diabetes mellitus, similar to the difference we observed.2 However, those investigators did not examine trends over time or case-fatality. Indeed, ours is the first population-based study of which we are aware to compare case-fatality after heart failure admissions in people with and without type 1 diabetes mellitus, and we are not aware that the high case-fatality in patients with type 1 diabetes mellitus has been reported previously.Fewer studies have examined heart failure as a complication of type 1 diabetes mellitus. The largest, which was a population-based study from Sweden, and which updates and extends a previous report from the same diabetes mellitus registry,17 Notwithstanding the mechanisms, however, the increased case-fatality provides additional support for the view that heart failure is an under-recognized and important complication in type 1 diabetes mellitus.18The mechanisms underlying this difference in case-fatality are unknown, and mechanistic studies are needed. Indeed, excepting coronary artery atherosclerosis, the mechanisms underlying the relationship between diabetes mellitus and heart failure are not well understood, and whether or not diabetic cardiomyopathy represents a distinct entity remains controversial.19 Also, trends after heart failure admissions were examined for people with type 2 diabetes mellitus in a subset of the U.S. National Inpatient Sample mortality (defined using administrative data – ICD-9-CM codes 250.0–250.9 with a fifth digit of 0 or 2). In models adjusting for age and sex, case-fatality fell by ≈5% per year from 2000 to 2010.20 This is consistent, therefore, with our findings.Time trends in case-fatality were similar across groups. For people with and without diabetes mellitus, regardless of type, we found that case-fatality fell by around 3% per-year. We were unable to identify any previous study which compared heart failure admission case-fatality trends among people with and without diabetes mellitus. Nonetheless, similar trends have been reported in unselected patients, and in people with type 2 diabetes mellitus. In terms of the former, a study using the Swedish national hospital discharge register, which included 13.6% of people with type 2 diabetes mellitus, found a decline of ≈4% per-year (hazard ratio 0.96 per year during the 5-year period from 1987–2006).21 Lind et al14 also showed that, among people with type 1 diabetes mellitus, smoking, systolic blood pressure, high body mass index, duration of diabetes mellitus, and hemoglobin A1c were associated with increased heart failure incidence. We obtained similar findings for the association between these risk factors and the 3-year risk of heart failure among people with type 1 diabetes mellitus. We have also been able to show that very similar associations (both in terms of magnitude and direction) are evident for people with type 2 as well as type 1 diabetes mellitus.In the general adult population, a number of risk factors such as age, sex, deprivation, smoking, obesity, hypertension, cholesterol, and previous cardiovascular disease are known to predict heart failure.22 Importantly, these differences were still found after taking into account the fact that people with type 2 diabetes mellitus are older, and even after adjusting for each patient’s predicted risk of heart failure (based on their baseline characteristics). Considerable caution is needed in interpreting this finding, as the clinical risk factors  used to adjust for baseline risk were obtained as part of routine clinical care, not in a prospective study, and were not available for some patients. Nonetheless, this observation does raise the possibility that, even where the heart failure risk is similar, people with type 1 diabetes mellitus may be less likely than people with type 2 diabetes mellitus to receive preventative drug therapy.We also found that people with type 1 diabetes mellitus were less commonly prescribed drugs known to reduce the risk of heart failure (whether directly or through reducing the risk of heart disease); this included antihypertensives, drugs acting on the renin–angiotensin, system and lipid-lowering drugs.23 A limitation is that heart failure events insufficiently severe to require admission to hospital were not captured as we did not have access to primary care data.The strengths of our study include the very large population-based nature of the electronic record of diagnosed diabetes mellitus that captures data for >99% of the population of Scotland, information on the type of diabetes mellitus, and the availability of linkage to quality-assured hospital admission and mortality data for the whole population.24 Moreover, similar associations were found in a sensitivity analysis which restricted the definition of heart failure to admission where this was coded in the first diagnostic position.However, we have previously shown via review by 2 independent clinicians  that heart failure admissions in the Scottish hospitalization database are reliably recorded.Secondly, although the data were of high quality, some misclassification as a result of diagnostic uncertainty is likely to have occurred. In particular, some people with type 1 diabetes mellitus will have been classified as type 2 diabetes mellitus, and vice versa. However, there is no reason to suppose that this misclassification will have been differential by outcome, and it is therefore likely to have attenuated any observed differences between type 1 and type 2 diabetes mellitus. Indeed, in the cohort restricted to patients with diabetes mellitus in 2013, the use of a more precise definition of diabetes mellitus type did not importantly affect the estimated 3-year risk of diabetes mellitus. A further limitation is that we did not have accurate data on race or ethnicity, and so we cannot comment on whether associations between diabetes mellitus and heart failure incidence differ by these variables.Finally, we did not have access to sufficient data on left ventricular function to comment on the relative contribution of reduced and preserved ejection fraction heart failure on the differences between people with and without diabetes mellitus.Despite falling incidence rates, particularly in type 1 diabetes mellitus, heart failure remains ≈2-fold higher than in people without diabetes mellitus, with case-fatality also being higher in people with type 1 diabetes mellitus. Those with type 1 diabetes mellitus also received fewer preventative cardiovascular medications. These findings provide additional support for the view that heart failure is an under-recognized and important complication in diabetes mellitus, particularly among people with type 1 diabetes mellitus.Dr McAllister is funded via an Intermediate Clinical Fellowship and Beit Fellowship from the Wellcome Trust (201492/Z/16/Z).Dr Jhund reports grants from Boehringer Ingelheim, during the conduct of the study, and personal fees from Novartis, Cytokinetics, and Visor Pharma, outside the submitted work. Dr Petrie reports personal fees and other from Novo Nordisk, grants and personal fees from Sanofi Aventis, nonfinancial support from Merck (Germany), personal fees from Lilly, nonfinancial support from Itamar Medical, grants and personal fees from Quintiles, grants and personal fees from Janssen, personal fees from ACI Clinical, and personal fees from Pfizer, outside the submitted work. Dr Sattar’s employer received funding from Boehringer Ingelheim for a research grant, and Dr Sattar has received personal speaking fees from Boehringer Ingelheim, Novo Nordisk, Eli Lilly, and Roche Diagnostics and has acted as a consultant for Boehringer Ingelheim, Janssen, and Astrazeneca. Dr McMurray’s employer, Glasgow University, is currently or has recently been paid for his role in trials testing treatments in patients with diabetes mellitus: principal investigator DAPA-HF trial dapagliflozin AstraZeneca, principal investigator BEST trial bexagliflozin Theracos, coprincipal Investigator HARMONY Outcomes trial albiglutide GSK, executive committee member DAPA-CKD trial dapagliflozin AstraZeneca, executive committee member ACE trial acarbose Oxford University/Bayer, executive committee member SONAR trial atrasentan Abbvie, and data monitoring committee member EXSCEL trial exenatide AstraZeneca. Dr McMurray’s study sponsors have paid for his travel and accommodation for some meetings related to these trials. The remaining authors report no conflicts.


Kerboull-type acetabular support rings (KT) and allogenic bone graft were used for severe periacetabular bone loss with primary and revision total hip arthroplasty (THA). The purpose of this case–control study is to evaluate the risk factors related to poor outcomes of surgery.Sixty patients underwent primary THA and revision THA using allogenic bone graft with KT for large acetabular deficiency. These patients were retrospectively evaluated postoperatively and followed-up by radiograph. The minimum follow-up period was 4 years and averaged 7 years. A radiological failure was defined by the following criteria:1)substantial migration defined as change in the angle of inclination of more than 5 degrees or migration of more than 5 mm,2)breakage of the screw or device,3)acetabular revision due to aseptic loosening.Expected risk factors were defined as female, age >75 years, body mass index (BMI) >25%, medical history of hypertension, renal failure, liver steatosis, diabetes, hyperlipidemia, cardiac infarction, smoking, American Academy of Orthopedic Surgery (AAOS) classification III or IV, bleeding>500 mL, time of surgery >3hours, high hip center-type KT, inclination of KT >45 degrees, screw angle >25 degrees, morselized bone graft, Kawanabe's classification stage 3 or 4 and revision surgery. Nineteen hips (31.6%) revealed radiological failure according to our criteria, and revision THA was performed in 2 hips (3.3%). In the statistical analysis, morselized bone graft and high hip center-type KT were identified as factors of poor outcomes of surgery. In addition, these bone grafts restore bone stock, which is a benefit should a future repeat revision become necessary. Multiple treatment options have been described for the reconstruction of acetabular bone deficiencies, including the use of autograft or allograft bone in conjunction with cemented or cementless components. Harris advocated replacement of the acetabular component at a high hip center at the time of revision. High placement of the cup makes it possible to avoid the use of a structural graft; however, the risk of impingement and dislocation increases. Placement of the cup at the correct anatomical level appears to decrease the risk of impingement and dislocation. A bone graft is necessary to place the cup at the original center of rotation. However, several authors described poor results in revision THA with a structural bone graft without a reinforcement device.–7 Gerber and Mulroy initially published good results using a structural bone graft for acetabular reconstruction at 7.1 years of follow-up; however, the number of revisions approximately doubled after an additional 5 years.,9 Garbuz described that a large structural allograft that supports more than 50% of the cup is necessary to reconstruct the acetabulum at the correct anatomical level for hips with severe deficiency of the acetabular bone stock. When the graft supports more than 50% of the cup, they advocate the use of a reconstruction device and a cup inserted with cement. On the other hand, major available devices have been used for acetabular revision, including Muller support ring, Burch-Schneider anti-protrusion cage, Ganz plate and Kerboull acetabular reinforcement device (Kerbull device). The Kerboull device was developed in 1974 and the Kerboull-type plate  is a similarly shaped, modified Kerboull device that KT introduced in 1993.,11 Additionally, KT provides variations in offset length and vertical length.Management of periacetabular bone loss during total hip arthroplasty (THA) and revision THA is an ongoing challenge for orthopedic surgeons. Garbuz proposed that the goals of the revision THA on the acetabular side are to provide support for the cup to reapproximate the normal anatomy and to restore the length of the lower limb.In the present study, 60 hips that underwent THA or revision THA with severe acetabular bone defect and underwent acetabular reconstruction using allogenic bone graft with KT between 1995 and 2014 were retrospectively evaluated. The focus was on factors related to poor outcomes of surgery.2This study was approved by the Institutional Review Board of the Hyogo College of Medicine (No. 2190), and informed consent was obtained from all patients.2.1 Stage 1 indicates no superior bone loss while the whole pallet of the KT is placed against the host bone. Stage 2 indicates superior bone loss, with more than 50% of the pallet in contact with the host bone. Stage 3 indicates superior bone loss with less than 50% of the palette touching the host bone. Stage 4 indicates massive bone loss with no part of the pallet touching the host bone. There were 14 hips with stage 1, 12 hips with stage 2, 13 hips with stage 3, and 21 hips with stage 4.Seventy patients underwent primary THA and revision THA using allogenic bone graft with KT for large acetabular deficiency between 1995 and 2014. Among these 70 patients, 2 patients underwent revision surgery due to deep infection and 8 patients were lost during the study period without a follow-up. These 10 patients were excluded from this study. In total, 60 patients were included in this retrospective study. There were 10 male and 50 female patients with a mean age of 65.9 years . The minimum follow-up period was 4 years and averaged 7 years . During the follow-up periods, 11 patients died for reasons unrelated to THA, and the final follow-up period for these patients was defined as the time of their death. There were 25 primary THAs and 35 revision THAs. Hip pathologies in primary THA included osteoarthritis in 2 hips, rapidly destructive coxarthropathy in 3 hips, rheumatoid arthritis with protrusio acetabuli in 12 hips, post-traumatic osteoarthritis in 4 hips, hemophilic arthritis in 1 hip, and hemodialysis-related arthritis in 3 hips. During surgery, the acetabular defect was classified according to the American Academy of Orthopedic Surgery (AAOS) system of grading and the total number of each type is as follows: Type I in 19 hips, Type II in 15 hips, Type III in 23 hips, and Type IV in 3 hips. Additional grading by Kawanabe's classification of the acetabular bone defect was performed according to the severity of the superior segmental bone loss.2.2 The hook of the KT plate was placed under the teardrop area and at least 2 screws were passed through the palette of the KT to fix it to the pelvis. In severe cases of AAOS type III or Kawanabe's stage 4, the palette of the KT could not be attached directly to the pelvis due to superior bone defect. In these cases, all screws were fixed to the pelvis through a structural bone graft. Post-operative management included partial weight bearing immediately after surgery, and full weight bearing was allowed 3 to 4 weeks after surgery in all patients.All procedures were performed by 1 senior surgeon (SF) who is experienced in the surgical technique for revision THA. In the THA procedure, surgeries were performed in the lateral position with a direct-lateral approach. Allogenic bone graft was used for all included patients. The graft bone was obtained from the femoral head of osteoarthritis patients during the previous primary THA, and it was harvested under sterile conditions using a Lobator sd-2  and stored at −80 degrees. These procedures were performed according to the guidelines of the Japanese Orthopedic Society. The morselized bone graft was used for acetabular bone defects in 30 hips until 2007. Since 2007, a structural bone graft was used in 30 hips for superior acetabular bone defects. Additionally, the morselized bone was packed into the gaps between the structural bone graft and host bone. KT was used for all cases as a reinforcement device, and to protect the graft bone. KT has various types of offsets and vertical lengths including a vertical offset of 0 mm, 10 mm, and 15 mm; however, they have been classified into the following 2 types: original cup center-type with a vertical offset of 0 mm  and high hip center-type with a vertical offset of 10 mm and 15 mm (high hip center-type [HH]) substantial migration,2)breakage or loosening of the screw or device, and3)acetabular revision due to aseptic loosening.The focus was on factors related to poor outcomes of surgery, such as radiological failure. Regarding patient-related factors, we evaluated sex, age, body mass index (BMI), medical history of hypertension, renal failure, liver steatosis, diabetes, hyperlipidemia, cardiac infarction, smoking, and AAOS classification before surgery. For surgery-related factors, bleeding, time of surgery, type of KT (OC-type or HH-type), inclination angle of KT, the average angle of the screws, type of bone graft , Kawanabe's classification, and the type of surgery (revision THA or primary THA) were evaluated. Expected risk factors were defined as female, age >75 years, BMI >25%, medical history of hypertension, renal failure, liver steatosis, diabetes, hyperlipidemia, cardiac infarction, smoker, AAOS classification III or IV, bleeding >500 mL, time of surgery >3hours, HH-type KT, inclination of KT >45 degrees, screw angle >25 degrees, morselized bone graft, Kawanabe's classification stage 3 or 4, and revision surgery.2.4P <.05 in the univariate analysis were further analyzed in the multivariate logistic regression analysis. Results were summarized as odds ratios, 95% confidence intervals, and P values P <.05, which were considered statistically significant. The statistical analysis was performed using SPSS software .In the statistical analysis, a univariate analysis of potential risk factors was initially performed using Fisher exact test. Factors that were found to have values of 3substantial migration and breakage of the hook in the KT. Re-revision THA was performed using a structural bone graft and OC-type KT  revealed radiological failure according to our criteria. Seventeen hips developed substantial migration of KT. Among these 17 hips, 8 hips showed change in the angle of inclination of more than 5 degrees, 13 hips showed migration of more than 5 mm, and 4 hips showed both. Breakage of KT developed in 5 hips, and breakage or loosening of the screws developed in 2 hips. Finally, revision THA was performed in 2 hips (3.3%). The first case was a 57-year-old man who underwent revision THA due to upper migration of bipolar arthroplasty. The acetabular defect was classified as AAOS type III and Kawanabe's grading stage 3 during surgery. Revision THA was performed using a structural bone graft and HH-type KT. Ten years after revision surgery, the patient underwent re-revision THA for the acetabular side due to 1.6% reveP values of less than .05 were demonstrated in HH-type KT, inclination of KT >45 degrees and morselized bone graft. Other examined factors  did not significantly correlate with radiological failure  and morselized bone graft  were found to be risk factors for postoperative radiographic failure  for revision THA with KT. The survival rate with a mean follow-up duration of 7.4 years was 74.2%, 81.5%, and 94.7% for HA, beta-TCP, and bulk allograft, respectively. In the present study, radiological failure was revealed in 19 hips , which included 2 revisions  with a mean follow-up of 7 years. Similarly, radiological failure occurred in 15 hips using morselized bone graft , and in 4 hips with structural bone graft . The morselized bone grafts could be a related factor for poor outcomes in acetabular reconstruction using KT.The Kerboull acetabular reinforcement device, which was developed in 1974, is characterized by the fixation of the primary acetabulum with a stainless-steel cup. The HH-type KT has a longer lever-arm between the dome and the hook, and it is hypothesized that over-stress in the hook could continue during the remodeling process of the graft bone. On the other hand, HH-type KT had the advantage when placing the cup at the high hip center, as it made it possible to decrease the volume of bone graft in cases with severe superior bone defect. However, these cases tend to increase the inclination angle of KT in order to attach the pallet to the pelvis. Kamada described that an inclination angle of KT of more than 45 degrees could lead to poor survivorship compared to an inclination angle of less than 45 degrees. Similar results showed that an inclination angle of KT of more than 45 degrees could be identified as one of the factors for poor outcomes of surgery in the univariate analysis in the present study. Several factors could have contributed to the results. When the OC-type KT was selected for cases with severe superior bone defect, a massive bone graft was necessary for the reconstruction. Jasty described that revascularization and osseous ingrowth in a large bulk bone graft after revision surgery takes several years, and may contribute to graft collapse. The graft bone should be partially unloaded and protected from excessive mechanical force during the remodeling process. Recently, Makita described that consolidation of the bone graft was completed within 12 months in Paprosky type 3A and 3B acetabular bone defect, and Oe described that The success rate of bone remodeling as radiological demarcation was 100% at bone-bone interface after acetabular reconstruction with KT in primary THA and 94% in revision THA. In later cases in the present study, we used one whole femoral head allograft for superior bone defects of the acetabulum in the cases of Kawanabe's Type IV. The palette of the KT could not be attached directly to the pelvis in these cases. The pallet was fixed to the pelvis through a femoral head allograft in OC-type KT. However, the whole femoral head allograft with OC-type KT for Kawanabe's Type IV acetabulum did not reveal radiological failure during the follow-up periods. It is hypothesized that the use of the OC-type KT protects the massive structural grafted bone through its screw fixation to the pelvis, thereby partially protecting the grafted bone from excessive loading during the incorporation and remodeling process. On the other hands, Hayashi reported a risk factor for failure of revision THA using KT and proposed that severe acetabular defects, which are AAOS type IV, was a risk factor for radiographic failure. In the present study, however, AAOS classification III and IV did not significantly correlate with radiological failure. Therefore, use of the OC-type KT and structural bone graft were preferred for any type of acetabula defect according to the clinical and radiological results. Following the present study, sufficient structural bone graft seems to be necessary to avoid the inclination of OC-type KT of more than 45 degrees in our current practice in order to improve long term survivorship of the surgery.Another factor for poor outcomes of surgery was revealed through the use of an HH-type KT. There have been no previous papers mentioning this type of KT. In the present study, radiological failure was revealed in 16 hips  using HH-type KT and in 3 hips  using OC-type KT. There were significant differences between the 2 types of devices. In addition, 4 of 33 cases (12.1%) revealed breakage of the hook in HH type KT. Kawanabe described the finite element model (FEM) study in which high-stress areas were localized on the hook and the bend of the pallet, but not on the inner side of the device.Limitations: There are several limitations in this study. First, the follow-up period was relatively short and a longer follow-up might have been necessary. Second, using a morselized bone graft resulted as a risk factor, leading to poor outcomes of surgery; however, this has been utilized in our initial series of surgeries between 1995 and 2007, and from 2007 onwards structural bone graft has been used. It is possible that a learning curve exists for improving our surgical technique. Third, the present study retrospectively evaluated radiographs and medical charts. It is not clear why HH-type KT was chosen for surgery of acetabular defects; however, it is possible that HH-type KT was chosen instead of OC-type KT for cases of severe acetabular deficiency.Future directions: Current surgical options for severe acetabular deficiency in THA or THA revision is will follow the results of this retrospective study. We used OC-type KT for the cup placed original acetabulum and sufficient volume of the structural bone graft was used in order to avoid an inclination angle of KT of more than 45 degrees.In conclusion, the morselized bone graft and HH-type KT resulted in becoming risk factors for primary and revision THA with acetabular reconstruction using allogenic bone graft and KT in severe acetabular deficiency.The authors thank Mr Devin Casadey and Ms Rebecca Imaizumi for their assistance in editing the English of this manuscript.Conceptualization: Shigeo Fukunishi.Data curation: Yoshinobu Masumoto, Tomokazu Fukui, Yu Takeda, Shoji Nishio, Yuki Fujihara, Shohei Okahisa, Taishi Okada.Formal analysis: Yoshinobu Masumoto, Tomokazu Fukui, Yu Takeda, Shoji Nishio, Yuki Fujihara, Shohei Okahisa, Taishi Okada.Funding acquisition: Yoshinobu Masumoto, Tomokazu Fukui, Yu Takeda, Shoji Nishio, Yuki Fujihara, Shohei Okahisa, Taishi Okada.Investigation: Yoshinobu Masumoto, Tomokazu Fukui, Yu Takeda, Shoji Nishio, Yuki Fujihara, Shohei Okahisa, Taishi Okada.Methodology: Shigeo Fukunishi, Yu Takeda.Project administration: Shigeo Fukunishi.Resources: Shigeo Fukunishi.Supervision: Shigeo Fukunishi, Shinichi Yoshiya.Validation: Shigeo Fukunishi, Shinichi Yoshiya.Visualization: Yoshinobu Masumoto.Writing – original draft: Yoshinobu Masumoto.Writing – review & editing: Shigeo Fukunishi, Shinichi Yoshiya.