L-Arginine Improves Post-Ischemic Vasodilation in Coronary Heart Disease Patients Taking Vasodilating Drugs

Background: The hypothesis that intravenous L-arginine infusion improves the vasodilatory response to ischemia in the resistance vessels of human lower limbs in relatively young coronary heart disease patients taking vasodilating drugs was tested. Methods: Twenty patients with onset of symptoms of coronary artery disease before age 50, operated for aortocoronary bypass and taking vasodilating drugs, were compared with 20 control subjects of comparable age and gender; neither group included heavy smokers (>10 cigarettes/day). Blood flow in the lower limbs was measured noninvasively with strain-gauge plethysmography, both at rest and during a reactive hyperemia test. Intravenous infusion of L-arginine was performed in nine coronary heart disease patients and in nine control subjects. Results: Resting blood flow to the lower limbs was 2.3 mI,/minIlO0 mL in control subjects vs 3.4 mL/minIlO0 mL in patients (difference not statistically significant). Peak blood flow measured after a 3-minute arterial occlusion was 24.0 mL/min/lO0 mL in control subjects vs 20.3 mL/min/lO0 mL in coronary heart disease patients (P