Abstract 4393: Preserved Coronary Flow Reserve Is A Necessary Condition For Remarkable Improvement Of Left Ventricular Contractile Function In Patients With Dilated Cardiomyopathy
Backgrounds: We sometimes experience cases of dilated cardiomyopathy (DCM) whose left ventricular (LV) contractile function has remarkably improved and nearly normalized within several months after the initiation of the optimal medical treatment with beta blocker and rennin-angiotensin system (RAS) inhibitor. However, this phenomenon has not been widely recognized and its importance has been underevaluated. Recent studies have reported the clinical significance of coronary flow reserve (CFR) as a predictor of future cardiac events in DCM. Thus we sought to examine whether there is any association between coronary flow reserve and response of LV function to the optimal medical treatment for DCM.
Method: We enrolled 72 DCM patients with decompensated heart failure (46 males and 26 females, age:59 ± 12 years). Patients with alcohol abuse, history of tachyarrhythmia, clinical symptom of prior infectious disease, or overt clinical findings suggesting secondary cardiomyopathy were excluded. After stabilizing the status of heart failure, beta blocker and RAS inhibitor were started. Within one week, CFR was measured with Doppler wire in LAD in all the patients and endomyocardial biopsy was performed in 54 patients. Echocardiogram was repeatedly performed before discharge and 6 months later to evaluate the change of LV ejection fraction (EF).
Results: In 21 patients, LV systolic function was nearly normalized (> LVEF 50%) 6 months later (Group I, LVEF: 32.2 ± 6.4% to 55.1 ± 4.4 %). In the remaining 51 patients, change of LVEF was not remarkable (Group II: LVEF: 31.9 ± 8.4% to 38.1 ± 9.4 %). There were no significant differences of clinical parameters including baseline LVEF, mitral regurgitation grade, and BNP level between 2 groups. CFR was decreased (< 2.5) in 1 patients in group I and 23 patients in group II (4.7% vs. 45.1%, p < 0.01). Change of LVEF was positively correlated with CFR (R = 0.654, p < 0.05). Neither the severity of degradation of cardiomyocyte nor the extent of myocardial fibrosis was associated with the improvement.
Conclusions: Preserved coronary flow reserve is a necessary condition for remarkable improvement of left ventricular contractile function in patients with dilated cardiomyopathy. Endomyocardial biopsy cannot predict this phenomenon.