Effect of Long-Term L-Arginine Supplementation on Arterial Compliance and Metabolic Parameters in Patients with Multiple Cardiovascular risk Factors: Randomized, Placebo-Controlled Study.

OBJECTIVES:: This study was designed to determine the effect of long-term L-arginine supplementation on arterial compliance, inflammatory and metabolic parameters in patients with multiple cardiovascular risk factors. METHODS:: In this randomized, placebo-controlled trial, 90 patients were randomly assigned to two groups: Group 1 received daily oral L-arginine, Group 2 received matching placebo capsules. Patients were evaluated for lipid profile, glucose, HbA1C, insulin, hs-CRP, renin and aldosterone .Arterial elasticity was evaluated using pulse wave contour analysis (HDI CR 2000, Eagan, Minnesota). RESULTS:: Although large artery elasticity index (LAEI) did not differ significantly between the groups at baseline (10.64.3 vs.11.64.5 ml/mm HgX100, p=0.346), at the end of the study LAEI was significantly greater in patients treated with L-arginine than in the placebo group (12.73.4 vs. 8.02.8 ml/mm HgX10, p<0.0001). Systemic vascular resistance was significantly lower in patients treated with L-arginine than in the placebo group after 6 months. Small artery elasticity index (SAEI) did not differ significantly between the groups at baseline or at the end of the study. Serum aldosterone decreased significantly in Group 1 from 10.76.3 to 8.45.0 ng/ml (p=0.008), but did not change in the placebo group. CONCLUSION:: L-arginine supplementation improves LAEI in patients with multiple cardiovascular risk factors. This improvement was associated with a decrease in systolic blood pressure, peripheral vascular resistance as well as a decrease in aldosterone levels. The results suggest that long term L-arginine supplementation has beneficial vascular effects in pathologic disease states associated with endothelial dysfunction.