ABNORMAL VASCULAR-RESPONSES IN HUMAN CHRONIC CARDIAC-FAILURE ARE BOTHENDOTHELIUM-DEPENDENT AND ENDOTHELIUM-INDEPENDENT

Objective-To study underlying vascular responses in chronic heart fail ure in patients without ACE inhibitor treatment, and to compare them w ith age matched controls. Design-Forearm blood flow was studied using venous occlusion plethysmography in patients with chronic :heart failu re (n = 12) and matched controls (n = 13), after infusion of L-NMMA (a nitric oxide synthase inhibitor), glyceryl trinitrate tan endothelium independent vasodilator), and serotonin tan endothelium dependent vas odilator). Results-NMMA produced significant vasoconstriction in norma l subjects (forearm blood flow reduced by:24%), but not in patients (6 %; difference between groups p < 0.03). The vasodilator responses to g lyceryl trinitrate were impaired in patients (p < 0.02). In normal con trols, serotonin produced initial dilatation, followed by vasoconstric tion at high doses. In patients, no vasodilator responses were observe d, only late vasoconstriction (p < 0.03). Conclusions-The vascular res ponses of patients are confirmed as being abnormal. The lack of respon se to L-NMMA suggests that nitric oxide does not contribute to basal v ascular tone in patients with chronic heart failure. The responses to glyceryl trinitrate and to serotonin suggest that there is both smooth muscle and endothelial dysfunction in patients with chronic heart fai lure.