Background: Platelet aggregation is a dominant feature in the pathophysiology of unstable angina. Percutaneous transluminal coronary angioplasty (PTCA) in patients with this disorder carries an increased risk of thrombotic complications. Abciximab (c7E3) blocks the platelet glycoprotein IIb/IIIa receptor, thus preventing platelet adhesion and aggregation. The CAPTURE study was a randomised placebo-controlled multicentre trial to assess whether abciximab can improve outcome in patients with refractory unstable angina who are undergoing PTCA.
Methods: The study recruited patients with refractory unstable angina, defined as recurrent myocardial ischaemia under medical treatment including heparin and nitrates. Predefined stopping rules were met at a planned interim analysis of data for 1050 patients, and recruitment was stopped. Data for 1265 patients (of 1400 scheduled) are presented here. After angiography, patients received a randomly assigned infusion of abciximab or placebo for 18-24 h before PTCA, continuing until 1 h afterwards. The primary endpoint was the occurrence within 30 days after PTCA of death (any cause), myocardial infarction, or urgent intervention for recurrent ischaemia. Analyses were by intention to treat.
Findings: By 30 days, the primary endpoint had occurred in 71 (11.3%) of 630 patients who received abciximab compared with 101 (15.9%) of 635 placebo recipients (p = 0.012). The rate of myocardial infarction was lower in the abciximab than in the placebo group before PTCA (four [0.6%] vs 13 [2.1%], p = 0.029) and during PTCA (16 [2.6%] vs 34 [5.5%], p = 0.009). Major bleeding was infrequent, but occurred more often with abciximab than with placebo (24 [3.8%] vs 12 [1.9%], p = 0.043). At 6-month follow-up, death, myocardial infarction, or repeat intervention had occurred in 193 patients in each group.
Interpretation: In patients with refractory unstable angina, treatment with abciximab substantially reduces the rate of thrombotic complications, in particular myocardial infarction, before, during, and after PTCA. There was no evidence that this regimen influenced the rate of myocardial infarction after the first few days, or the need for subsequent reintervention.