By Ed Susman
CHICAGO -- April 1, 2008 -- Researchers suggested that abciximab or other glycoprotein IIB/IIIA inhibitors are unnecessary if patients with acute myocardial infarction (MI) are preloaded with clopidogrel 600 mg before they undergo percutaneous coronary interventions.
The researchers presented data to support this theory in a late-breaker session here at the Society for Cardiovascular Angiography and Interventions (SCAI) Annual Scientific Sessions, held in conjunction with the American College of Cardiology Innovation in Intervention: i2 Summit.
"Abciximab adds no benefit to these patients and may cause some harm," said Julinda Mehilli, MD, Associate Professor and Staff Cardiologist, Deutsches Herzzentrum, Technical University, Munich, Germany.
Dr. Mehilli and colleagues randomised patients to receive abciximab plus clopidogrel if they were being treated with interventional techniques during an acute MI, and another group of similar patients were randomised to receive clopidogrel alone. The outcomes in these patients were virtually identical.
In her presentation on March 30, Dr. Mehilli noted that clopidogrel 300 mg improved outcomes in previous clinical trials, and since then further research has identified clopidogrel 600 mg as a dose in which additional platelet inhibition occurs.
The aim of her study was to determine if the addition of abciximab further reduces infarct size among patients with ST-elevation MI if the patients undergo percutaneous coronary intervention after being preloaded with clopidogrel 600 mg.
Patients underwent single photon emission computed tomography scans within 5 to 7 days of randomisation. The size of the infarct was the primary endpoint of the study. Secondary endpoints included death, MI, revascularisation, stroke, bleeding, and profound thrombocytopenia.
All patients were given 600 mg of oral clopidogrel, 500 mg of intravenous or oral aspirin, and 5000 IU of unfractionated heparin. Patients were then divided into 2 groups; 401 patients were assigned to receive abciximab and 399 to receive placebo. After the percutaneous procedure, all patients were put on aspirin 200 mg/day indefinitely, clopidogrel 75 mg twice daily for 3 days, and clopidogrel 75 mg daily for at least 4 weeks.
Mean infarct size was 15.7% of the left ventricle for patients in the abciximab group and 16.6% for patients in the placebo group (P = .47). The 30-day mortality was about 3.00% for patients on abciximab and 2.25% for those on placebo (P = .53). There was a greater risk of thrombocytopenia in patients who received the combination treatment.
"In patients with acute ST-elevation myocardial infarction undergoing primary percutaneous coronary interventions after pretreatment with 600 mg of clopidogrel, the additional use of abciximab is not associated with further reduction in infarct size," Dr. Mehilli said.
The paper's discussant Gregg W. Stone, MD, Director, Cardiovascular Research and Education Center for Interventional Vascular Therapy, NewYork-Presbyterian Hospital/ Columbia University, New York, New York, said Dr. Mehilli's study is valid because "clinical and scientific equipoise existed on the subject. We really didn't know -- even before the clopidogrel era -- whether abciximab improved infarct size. I think this is a very important and insightful trial and enhances our scientific understanding of this complex disease state."
Dr. Stone added that the study may be limited because in some cases infarct size may have been a fait accompli before the drugs were on board due to late treatment of the patients in the study.
[Presentation title: Abciximab in Patients With AMI Undergoing Primary PCI After Clopidogrel Pretreatment: Brave-3 Trial (Bavarian Reperfusion Alternatives Evaluation 3 Trial). Abstract 2404-7]
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