Prevention of endothelial dysfunction in small and large arteries in a model of chronic heart failure

Chronic heart failure (CHF) impairs endothelium dependent vasodilatation of large conductance arteries. We investigated whether a similar reduction also occurs in small arteries, and whether such a reduction can be prevented by the angiotensin converting enzyme inhibitor perindopril (P) in a rat model of CHF (left coronary artery ligation). After 1 month treatment with placebo or P (2 mg/kg/day), rats were anesthetized and arterial pressure, left ventricular end-diastolic pressure, and central venous pressure were measured with a micromanometer. Segments of aorta and mesenteric artery (mean diameter, 281 ± 8 μm) were then isolated, cannulated, and perfused at constant pressure using an arteriograph. Responses to increasing concentrations of acetylcholine (Ach), nitroprusside, and to 10 −4 mol/L N G -nitro- l -arginine methyl ester (L-NAME) were studied after preconstriction by phenylephrine. Heart failure resulted in a decrease in systolic and diastolic pressures, an increase in left ventricular end-diastolic and central venous pressures, and a significant depression of Ach-induced dilatation of the mesenteric artery (maximal dilatation, from 90 ± 4% to 63 ± 4%, P < .05) but not of the aorta (from 56 ± 8% to 45 ± 5%, NS) without any modification in the ertdothelium-independent vasodilatation induced by nitroprusside. In the group treated by the angiotensin converting enzyme (ACE) inhibitor perindopril, systolic and diastolic pressures were slightly decreased, whereas left ventricular end diastolic, central venous pressures, and the endothelium-dependent vasodilating response to Ach were normalized. Responses to L-NAME were not affected by CHF or perindopril. Perindopril also decreased hypertrophy, as evidenced by a significantly lower heart weight in treated rats. Thus, CHF decreases the endothelium-dependent response to Ach, which is heterogeneous and mainly affects small arteries, whereas the basal release of NO appears unaffected. This CHF-induced dysfunction could be prevented by chronic ACE inhibition.