Microvascular Dysfunction in Dilated Cardiomyopathy: A Quantitative Stress Perfusion Cardiovascular Magnetic Resonance Study.
OBJECTIVES
This study sought to quantify myocardial blood flow (MBF) and myocardial perfusion reserve (MPR) in dilated cardiomyopathy (DCM) and examine the relationship between myocardial perfusion and adverse left ventricular (LV) remodeling.


BACKGROUND
Although regarded as a nonischemic condition, DCM has been associated with microvascular dysfunction, which is postulated to play a role in its pathogenesis. However, the relationship of the resulting perfusion abnormalities to myocardial fibrosis and the degree of LV remodeling is unclear.


METHODS
A total of 65 patients and 35 healthy control subjects underwent adenosine (140 μg/kg/min) stress perfusion cardiovascular magnetic resonance with late gadolinium enhancement imaging. Stress and rest MBF and MPR were derived using a modified Fermi-constrained deconvolution algorithm.


RESULTS
Patients had significantly higher global rest MBF compared with control subjects (1.73 ± 0.42 ml/g/min vs. 1.14 ± 0.42 ml/g/min; p < 0.001). In contrast, global stress MBF was significantly lower versus control subjects (3.07 ± 1.02 ml/g/min vs. 3.53 ± 0.79 ml/g/min; p = 0.02), resulting in impaired MPR in the DCM group (1.83 ± 0.58 vs. 3.50 ± 1.45; p < 0.001). Global stress MBF (2.70 ± 0.89 ml/g/min vs. 3.44 ± 1.03 ml/g/min; p = 0.017) and global MPR (1.67 ± 0.61 vs. 1.99 ± 0.50; p = 0.047) were significantly reduced in patients with DCM with LV ejection fraction ≤35% compared with those with LV ejection fraction >35%. Segments with fibrosis had lower rest MBF (mean difference: -0.12 ml/g/min; 95% confidence interval: -0.23 to -0.01 ml/g/min; p = 0.035) and lower stress MBF (mean difference: -0.15 ml/g/min; 95% confidence interval: -0.28 to -0.03 ml/g/min; p = 0.013).


CONCLUSIONS
Patients with DCM exhibit microvascular dysfunction, the severity of which is associated with the degree of LV impairment. However, rest MBF is elevated rather than reduced in DCM. If microvascular dysfunction contributes to the pathogenesis of DCM, then the underlying mechanism is more likely to involve stress-induced repetitive stunning rather than chronic myocardial hypoperfusion.
['Gulati|Ankur|A|', 'Ismail|Tevfik F|TF|', 'Ali|Aamir|A|', 'Hsu|Li-Yueh|LY|', 'Gonçalves|Carla|C|', 'Ismail|Nizar A|NA|', 'Krishnathasan|Kaushiga|K|', 'Davendralingam|Natasha|N|', 'Ferreira|Pedro|P|', 'Halliday|Brian P|BP|', 'Jones|Daniel A|DA|', 'Wage|Ricardo|R|', 'Newsome|Simon|S|', 'Gatehouse|Peter|P|', 'Firmin|David|D|', 'Jabbour|Andrew|A|', 'Assomull|Ravi G|RG|', 'Mathur|Anthony|A|', 'Pennell|Dudley J|DJ|', 'Arai|Andrew E|AE|', 'Prasad|Sanjay K|SK|']
D000328:Adult D002311:Cardiomyopathy, Dilated D016022:Case-Control Studies D003287:Contrast Media D003326:Coronary Circulation D005260:Female D005355:Fibrosis D006801:Humans D019028:Magnetic Resonance Imaging, Cine D008297:Male D008833:Microcirculation D008875:Middle Aged D055414:Myocardial Perfusion Imaging D009206:Myocardium D009942:Organometallic Compounds D011237:Predictive Value of Tests D011379:Prognosis D011446:Prospective Studies D014665:Vasodilator Agents D018487:Ventricular Dysfunction, Left D016277:Ventricular Function, Left D020257:Ventricular Remodeling
microvascular dysfunction myocardial blood flow dilated cardiomyopathy cardiovascular magnetic resonance imaging myocardial perfusion imaging