Aspirin Non-responsiveness and Clopidogrel Endpoint Trial. (ASCET)

The Norwegian Council for Cardiovascular Diseases., Ada and Hagbart Waages Humanitarian and Charity Foundation, Alf and Aagot Helgesens Research Foundation.

In the ASCET study, 1000 patients with documented coronary heart disease will be randomized to either continued treatment with aspirin 160 mg/d or change to clopidogrel 75mg/d. Clinical endpoints will be recorded for at least 2 years and related to the initial aspirin response, assessed by the PFA-100® method, to investigate whether aspirin non-responders have higher composite event rate than responders or whether Clopidogrel treatment in patients non-responsive to aspirin will reduce their risk of future clinical events. The clinical events are the composite of unstable angina, myocardial infarction, stroke or death.

Background: Aspirin is widely used as an antiplatelet drug in patients with coronary heart disease. Despite documented clinical benefit, many patients on aspirin still experience severe cardiovascular events. Several laboratory reports have shown lack of platelet inhibition in 5-40% of aspirin-treated patients, and the term aspirin resistance has been introduced. The clinical relevance of these laboratory findings is, however, still unknown. New antiplatelet drugs have been developed, and the adenosin diphosphate (ADP) receptor inhibitor clopidogrel has at least the same efficacy as aspirin with an acceptable safety profile. Laboratory methods for determination of platelet reactivity and treatment efficacy have been complicated and time consuming. New methodologies, like the PFA-100® system, have made such analyses more suitable for clinical use. Design: In the ASCET study, 1000 patients with documented coronary heart disease will be randomized to either continued treatment with aspirin 160 mg/d or change to clopidogrel 75mg/d after initial determination of their platelet reactivity while on aspirin treatment. Clinical endpoints will be recorded for at least 2 years and related to the initial aspirin response. Scand Cardiovasc J. 2004 Dec;38(6):353-6.

antiplatelet therapy, aspirin non-responders, aspirin resistance, clopidogrel, coronary heart disease, stable angina pectoris

Unstable angina with ECG changes or raised levels of cardiac markers not to be classified as a myocardial infarction

Inclusion Criteria: Stable, symptomatic coronary heart disease, verified by coronary angiography, being treated with angioplasty/stent implantation (PCI) or not. Exclusion Criteria: Indication for warfarin treatment. Indication for or contraindication to the study drugs. Pregnancy or breast-feeding. Malignancy that may interfere with life expectancy. Psychiatric disease, mental retardation, dementia, drug abuse, alcoholism or conditions that can severely reduce compliance.

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