Abstract 2406: Coronary Microvascular Function as a Target for Prevention of Systolic Heart Failure in Chronic Valvular Heart Disease: Aortic Regurgitation versus Mitral Regurgitation
Background: The coronary microvascular vasodilating function is an important determinant of patient outcomes in a number of clinical settings, including coronary artery disease, hypertensive heart disease, or cardiomyopathy. However, the characteristics or the implication of coronary microcirculation in valvular heart disease has not been fully elucidated. The present study was designed to assess coronary vasodilating function and its effects on systolic function in patients with aortic regurgitation (AR) and mitral regurgitation (MR).
Methods: Forty-four consecutive patients (66 yrs) with moderate to severe AR and 45 consecutive patients with moderate to severe MR (64 yrs) were enrolled for this study. All patients were free of coronary artery stenosis. Fifty-one age-matched patients without underlying cardiovascular disease served as controls. Endothelium-dependent and endothelium-independent vasodilating function of resistance coronary artery were assessed by coronary blood flow (CBF) response to acetylcholine and papaverine, respectively. Left ventricular ejection fraction (LVEF) was determined by echocardiography as an indicator of systolic function.
Results: In patients with AR, both %change in CBF response to acetylcholine and papaverine were significantly lower than controls (32 ± 61 vs 64 ± 84, 172 ± 87 vs 268 ± 105, p < 0.05, p < 0.01, respectively). Further, %change in CBF response to acetylcholine positively correlated with LVEF (r = 0.45, p < 0.01). In patients with MR, %change in CBF response to papaverine was significantly lower than controls (221 ± 123 vs 268 ± 105, p < 0.05), but %change in CBF response to acetylcholine was comparable with controls. Moreover, neither %change in CBF response to acetylcholine nor CBF response to papaverine had significant correlation with LVEF.
Conclusion: In patients with AR, both endothelium-dependent and endothelium-independent vasodilating function of resistance coronary artery were deteriorated. Further, endothelium-dependent vasodilating function may be associated with left ventricular systolic function. Our findings indicate coronary microvascular endothelial dysfunction as a potential target for prevention of systolic heart failure in patients with AR.