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Randomised placebo-controlled trial of abciximab before and during coronary intervention in refractory unstable
Insights
Abciximab significantly reduces thrombotic complications, particularly myocardial infarction, in patients with unstable angina undergoing percutaneous transluminal coronary angioplasty (PTCA). This treatment improves outcomes by preventing platelet aggregation during this high-risk procedure.
Area of Science:
- Cardiology
- Pharmacology
- Interventional Cardiology
Background:
- Platelet aggregation is central to unstable angina pathophysiology.
- Percutaneous transluminal coronary angioplasty (PTCA) in unstable angina patients carries a high risk of thrombotic complications.
- Abciximab, a glycoprotein IIb/IIIa receptor inhibitor, prevents platelet adhesion and aggregation.
Purpose of the Study:
- To evaluate the efficacy of abciximab in reducing thrombotic complications in patients with refractory unstable angina undergoing PTCA.
- The CAPTURE study aimed to assess if abciximab improves clinical outcomes in this high-risk patient group.
Main Methods:
- A randomized, placebo-controlled, multicenter trial (CAPTURE study) was conducted.
- 1265 patients with refractory unstable angina received either abciximab or placebo infusion before and during PTCA.
- The primary endpoint was the composite of death, myocardial infarction, or urgent intervention within 30 days post-PTCA.
Main Results:
- Abciximab treatment resulted in a significantly lower rate of the primary endpoint (11.3% vs. 15.9%, p=0.012) within 30 days.
- Rates of myocardial infarction before and during PTCA were significantly reduced with abciximab.
- While major bleeding was more frequent with abciximab (3.8% vs. 1.9%, p=0.043), overall 6-month outcomes showed no significant difference between groups.
Conclusions:
- Abciximab substantially reduces thrombotic complications, especially myocardial infarction, in patients with refractory unstable angina undergoing PTCA.
- The benefits of abciximab were observed before, during, and shortly after the procedure.
- No significant impact on myocardial infarction rates after the initial days or on the need for subsequent reintervention was found.
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.