20 patients with peripheral arterial obstructive disease (PAOD) participated in a blind placebo controlled study. They received infusions of saline (placebo) for seven consecutive days and for the next seven days, 60 mmol of L-arginine (L-ARG) intravenously. Following this i. v. therapy, they were treated with tablets of L-ARG at a dose of 1 g, 3 times per day for 21 days. After seven days of placebo treatment, an improvement in exercise tests, a rise in the ankle/arm pressure ratio (AAPR), and an increase of blood flow in both calves (claudicant and non-claudicant) were observed. However, these effects were much more significant following L-ARG infusions. Placebo did not affect platelet susceptibility and fibrinolysis in a significant manner. L-ARG infusions inhibited spontaneous ADP and collagen induced platelet aggregation and stimulated fibrinolysis. L-ARG caused a significant increase in cGMP blood concentration levels while saline had no such effect. Clinical effects were more intensive following a 3 weeks oral therapy with L-ARG, but the influence on platelet aggregability, fibrinolysis and cGMP did not appear to be stronger. Our results suggest that i.v. therapy followed by orally administered L-ARG may serve in the prevention and therapy of PAOD patients. These findings call for further controlled studies on a greater number of patients.

Keywords: peripheral arterial obstructive disease, treatment, L-arginine, Nitric Oxide, cGMP levels, platelet aggregability, Fibrinolysis