Prevention of coronary arterial renarrowing by continuous 3-day infusion of tissue plasminogen activator after successful percutaneous transluminal coronary angioplasty: a randomized, double-blind, placebo-controlled study.

: Vascular injury resulting from percutaneous transluminal coronary angioplasty (PTCA) and subsequent thrombus formation are important factors in the pathogenesis of coronary arterial restenosis. The present study was undertaken to determine whether infusions of tissue plasminogen activator (tPA), beginning immediately after PTCA, would decrease the renarrowing of the coronary arterial lumen. Patients were randomized and divided into two groups: one group (15 patients, 16 lesions) received continuous, 3-day, intravenous infusions of tPA (0.25 mg/kg/day in 0.9% saline), beginning immediately after successful PTCA, while the other group (17 patients, 17 lesions) received saline alone. Coronary angiography was performed before, immediately after, 24 hours after, and 3 months after PTCA. Coronary stenosis (%), reference diameters, and minimum luminal diameters were measured by quantitative coronary angiography. The incidence of restenosis tended to be lower in the tPA group than in the placebo group (tPA group, 13%; placebo group, 41%; NS), although diameter stenoses before and immediately after PTCA were not significantly different in the two groups. Three months later, however, diameter stenoses were significantly smaller in the tPA group (35.6 +/- 13.3 vs 47.7 +/- 18.9%; P<0.05). Thus, intravenous tPA infusion beginning immediately after successful PTCA may inhibit renarrowing of the coronary arterial lumen.