A randomized, placebo-controlled trial of enoxaparin after high-risk coronary stenting: The ATLAST trial

OBJECTIVES We performed a multicenter, double-blind placebo-controlled tria l to examine the efficacy and safety of enoxaparin in patients at high risk for stent thrombosis (ST). BACKGROUND The optimal antithrombotic regimen for such patients is unknown. METHODS We randomized 1,102 patients with clinical, angiographic or ultraso nographic features associated with an increased risk of ST to receive eithe r twice-daily injections of weight-adjusted enoxaparin or placebo for 14 da ys after stenting. All patients received aspirin and ticlopidine. The prima ry end point was a 30-day composite end point of death, myocardial infarcti on (MI) or urgent revascularization. RESULTS The target enrollment for the study was 2,000 patients. However, th e trial was terminated prematurely at 1,102 patients after interim analysis revealed an unexpectedly low event rate. The primary outcome occurred in 1 .8% enoxaparin-treated patients versus 2.7% treated with placebo (odds rati o [OR] 0.66; 95% confidence interval [CI] 0.29 to 1.5, p = 0.30); for death or Ml the rates were 0.9% vs. 2.2%, respectively (OR 0.41, 95% CI 0.14 to 1.2, p = 0.13); and for MI, 0.4% vs. 1.6%, respectively (OR 0.22, 95% CI 0. 05 to 0.99, p = 0.04). The groups had comparable rates of major bleeding (3 .3% for enoxaparin, 1.6% for placebo, p = 0.08), but minor nuisance bleedin g was increased with enoxaparin (25% vs. 5.1%, p < 0.001). CONCLUSIONS The clinical outcomes of patients at increased risk of ST are m ore favorable than previously reported, rendering routine oral antiplatelet therapy adequate for most. However, given its relative safety and potentia l to reduce the risk of subsequent infarction, a 14-day course of enoxapari n may be considered for carefully selected patients. (C) 2001 by the Americ an College of Cardiology.