Six-month angiographic and clinical follow-up of patients prospectively randomized to receive either tirofiban or placebo during angioplasty in the RESTORE trial

Abstract

Objectives. This study sought to investigate the effects of tirofiban versus placebo on the incidence of adverse cardiac outcomes and coronary artery restenosis at 6 months.Background. Tirofiban is a highly selective, short-acting inhibitor of fibrinogen binding to platelet glycoprotein IIb/IIIa. In a recent clinical study, tirofiban reduced the incidence of adverse cardiovascular events at both 2 and 7 days after coronary angioplasty or directional coronary atherectomy. This reduction persisted but was no longer statistically significant at 30 days.Methods. The Randomized Efficacy Study of Tirofiban for Outcomes and Restenosis (RESTORE) trial was a randomized, double-blind, placebo-controlled trial of tirofiban in patients undergoing balloon angioplasty or directional atherectomy within 72 h of presentation with either unstable angina pectoris or acute myocardial infarction. All patients received an initial bolus (10 μg/kg body weight over 3 min), followed by a 36-h infusion (0.15 μg/kg per min) of either tirofiban or placebo.Results. At 6 months the composite end point (either death from any cause, new myocardial infarction, bypass surgery for angioplasty failure or recurrent ischemia, repeat target vessel angioplasty or stent insertion for actual or threatened abrupt closure) occurred in 1,070 placebo group patients (27.1%) and 1,071 tirofiban group patients (24.1%, p = 0.11). Analysis of 6-month coronary arteriograms by means of quantitative coronary arteriography showed no significant difference between placebo- and tirofiban-treated patients in either the incidence of a ≥50% diameter stenosis (57% vs. 51%, p = NS), a loss of ≥50% of lumen diameter gained (50% vs. 50%, p = NS) or a loss of ≥0.72 mm of lumen diameter (44% vs. 42%, p = NS).Conclusions. The 3% absolute reduction in the incidence of the composite end point at 6 months (27.1% placebo vs. 24.1% tirofiban) was similar to that previously reported at 2 days (8.7% vs. 5.4%, p < 0.005), and there does not appear to be any late effect of tirofiban on clinical end points between day 2 and 6 months. Tirofiban did not reduce the incidence of restenosis at 6 months when defined in a number of ways.