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Aspirin in chronic cardiovascular disease and acute myocardial infarction
1Channing Laboratory, Department of Medicine, Harvard Medical School, Boston, Massachusetts 02146.
Insights
Low-dose aspirin significantly reduces the risk of major vascular events, including heart attack and stroke, in patients with existing cardiovascular disease. Early aspirin treatment during suspected myocardial infarction also lowers mortality and reinfarction rates.
Area of Science:
- Cardiology
- Pharmacology
- Epidemiology
Background:
- Low-dose aspirin irreversibly inhibits platelet cyclooxygenase, providing a mechanism for reducing thrombotic cardiovascular events.
- Observational studies suggest aspirin use may decrease cardiovascular disease risk by 20-30%.
Purpose of the Study:
- To evaluate the efficacy of aspirin in reducing vascular events in patients with a history of cardiovascular disease.
- To assess the benefit of early aspirin administration in suspected evolving myocardial infarction (MI).
Main Methods:
- Overview of 25 randomized trials involving patients with prior cardiovascular disease.
- Analysis of the Second International Study of Infarct Survival (ISIS-2) data for patients with suspected evolving MI.
Main Results:
- Aspirin reduced "important vascular events" by 25% in patients with prior cardiovascular disease.
- Significant reductions observed in nonfatal MI (32%), nonfatal stroke (27%), and vascular mortality (15%).
- Early aspirin administration in evolving MI led to a 23% reduction in vascular mortality and fewer reinfarctions and strokes.
Conclusions:
- Aspirin is of proven value for patients with a history of MI, stroke, transient ischemic attack, or unstable angina.
- Aspirin significantly reduces the risk of reinfarction, stroke, and vascular mortality in patients with suspected evolving MI.
Abstract:
The ability of low-dose aspirin to irreversibly inhibit platelet-dependent cyclooxygenase provides a biologic mechanism to explain why this drug may decrease the risk of thrombotic cardiovascular events. Observational epidemiologic studies, both case-control and cohort, have suggested that aspirin might reduce the risk of cardiovascular disease by approximately 20 to 30%. An overview of 25 randomized trials of aspirin among individuals with a history of prior cardiovascular disease demonstrated that those receiving aspirin experienced a significant 25% reduction in the occurrence of "important vascular events," an endpoint that combines nonfatal myocardial infarction (MI), nonfatal stroke, and cardiovascular death. There were also significant 32% reductions in subsequent nonfatal MI, 27% reductions in nonfatal stroke, and 15% reductions in vascular mortality. Thus, individuals with a history of MI, stroke, transient ischemic attack, or unstable angina clearly benefit from aspirin. The Second International Study of Infarct Survival (ISIS-2) sought to determine if benefits would accrue if aspirin was given within the first 24 hours of suspected evolving MI. The aspirin group experienced a significant 23% reduction in 5-week vascular mortality compared with those receiving placebo. Aspirin was also associated with significantly fewer reinfarctions and strokes. Thus, among those with suspected evolving MI, aspirin significantly reduces the risk of reinfarction, stroke, and vascular mortality. These analyses indicate that aspirin is of proven value in the therapy of most patients who have survived MI, stroke, or unstable angina, as well as those evolving a suspected MI.(ABSTRACT TRUNCATED AT 250 WORDS)