Effect of short-term administration of high dose L-arginine on restenosis after percutaneous transluminal coronary angioplasty.

BACKGROUND: A single and local administration of L-arginine after balloon angioplasty enhances nitric oxide (NO) generation and inhibits lesion formation in animals.

OBJECTIVES: The present study assessed the effect of increasing NO to inhibit restenosis after percutaneous transluminal coronary angioplasty (PTCA) in humans by local and systemic administration of L-arginine, a precursor of NO in humans.

METHODS: L-arginine was administered to 34 consecutive patients with angina pectoris or old myocardial infarction via a cardiac catheter (500 mg/4 min) before PTCA, and via a peripheral vein (30 g/4 hr, for 5 days) after PTCA. Patients were treated between December 1998 and December 2000. Plasma concentrations of L-arginine, NO (as nitrite + nitrate) and cyclic guanosine monophosphate (cGMP) were measured before and after L-arginine administration. The control group consisted of 90 patients who underwent PTCA successfully without L-arginine administration in the period between July 1996 and November 1998. Baseline clinical and angiographic characteristics were compared between the two groups. All patients were followed by coronary angiography for 3 months after PTCA. Quantitative coronary angiography and restenosis rate were studied.

RESULTS: Baseline clinical and angiographic characteristics were not different between the two study groups. Despite a significant elevation in plasma L-arginine concentration after L-arginine administration, NO and cGMP did not increase significantly. After PTCA, the difference in restenosis rates between L-arginine and control subjects (34% vs 44%) was not significantly different.

CONCLUSIONS: Short-term administration of high dose L-arginine did not significantly change the restenosis rate after PTCA.