Correction of endothelial dysfunction in chronic heart failure: Additionaleffects of exercise training and oral L-arginine supplementation

OBJECTIVES The aim of this study was to analyze whether L-arginine (L-arg.) has comparable or additive effects to physical exercise regarding endothel ium dependent vasodilation in patients with chronic heart failure (CHF). BACKGROUND Endothelial dysfunction in patients with CHF can be corrected by both dietary supplementation with L-arg. and regular physical exercise. METHODS Forty patients with severe CHF (left ventricular ejection fraction 19 +/- 9%) were randomized to an L-arg. group (8 g/day), a training group ( T) with daily handgrip training, L-arg, and T (L-arg. + T) or an inactive c ontrol group (C). The mean internal radial artery diameter was determined a t the beginning and after four weeks in response to brachial arterial admin istration of acetylcholine (ACh) (7.5, 15, 30 mu g/min) and nitroglycerin ( 0.2 mg/min) with a transcutaneous high-resolution 10 MHz A-mode echo tracki ng system coupled with a Doppler device. The power of the study to detect c linically significant differences in endothelium-dependent vasodilation was 96.6%. RESULTS At the beginning, the mean endothelium-dependent vasodilation in re sponse to ACh, 30 mu g/min was 2.54 +/- 0.09% (p = NS between groups). Afte r four weeks, internal radial artery diameter increased by 8.8 +/- 0.9% aft er ACh 30 mu g/min in L-arg. (p < 0.001 vs. C), by 8.6 +/- 0.9% in T (p < 0 .001 vs. C) and by 12.0 +/- 0.3% in L-arg, + T (p < 0.005 vs. C, L-arg. and T). Endothelium independent vasodilation as assessed by infusion of nitrog lycerin was similar in all groups at the beginning and at the end of the st udy. CONCLUSIONS Dietary supplementation of L-arg. as well as regular physical e xercise improved agonist-mediated, endothelium-dependent vasodilation to a similar extent. Both interventions together seem to produce additive effect s with respect to endothelium-dependent vasodilation. (C) 2000 by the Ameri can College of Cardiology.