IMPAIRED ENDOTHELIUM-MEDIATED VASODILATION IN THE PERIPHERAL VASCULATURE OF PATIENTS WITH CONGESTIVE-HEART-FAILURE

Impaired endothelial-dependent vasodilation has been demonstrated in t wo animal models of congestive heart failure and in the coronary circu lation of patients with idiopathic dilated cardiomyopathy. To determin e whether this impairment contributes to the abnormal peripheral vasom otor tone in patients with congestive heart failure, the local vascula r response to intraarterial infusions of graded concentrations (10(-8) M to 10(-5) M) of acetylcholine (an endothelial-dependent vasodilator ) and nitroglycerin (a direct-acting vasodilator) was studied in the s uperficial femoral artery of 19 patients with congestive heart failure (New York Heart Association classes I to IV) and 6 age-matched normal control subjects. The local vascular response was determined from the arterial blood flow velocity pattern obtained by transcutaneous Doppl er ultrasonography. Acetylcholine, 10(-5) M, induced a pattern charact eristic of vasodilation in all six normal subjects; mean blood flow ve locity for the group significantly increased from 11.9 +/- 2.7 to 44.8 +/- 20.9 cm/s (p < 0.05). In contrast, the same dose of acetylcholine induced a blood flow velocity pattern characteristic of vasodilation in only 4 of the 19 patients with congestive heart failure. Group mean blood flow velocity did not change significantly. Nitroglycerin, 10(- 7) M, induced vasodilation in all 6 normal subjects but in only 1 of 1 9 patients. Nitroglycerin, 10(-5) M, was administered to 10 patients; all 10 demonstrated a pattern characteristic of vasodilation. Thus, ac etylcholine-mediated endothelial-dependent vasodilation appears to be impaired in the peripheral vasculature of patients with congestive hea rt failure. Both endothelial dysfunction and abnormal vascular smooth muscle responsiveness may contribute to abnormal peripheral vasomotor tone.