Aspirin-Myocardial Infarction Study (AMIS)
Condition: Cardiovascular Diseases; Coronary Disease; Heart Diseases; Myocardial Infarction; Myocardial Ischemia
MeSH terms: Cardiovascular Diseases; Heart Diseases; Myocardial Infarction; Coronary Disease; Myocardial Ischemia; Infarction; Ischemia
Study type: Interventional
Phase: Phase 3

Summary: 
      To determine whether the daily administration of 1 gm of aspirin to individuals with a
      documented myocardial infarction would result in a significant reduction in mortality over a
      three year period.
    

Detailed description: 
      BACKGROUND:

      It had been postulated that thrombosis plays a major role in the late stages of coronary
      artery occlusion. Platelet aggregation is a large component in the formation of arterial
      thrombi. Theoretically, an agent which prevents the aggregation of platelets would be of
      value in people with coronary artery disease. Aspirin, in small doses, inhibits platelet
      aggregation for prolonged periods of time, and therefore might be expected to prevent or
      retard the occlusion of coronary arteries. This would be reflected in a decrease in the
      incidence of myocardial infarction and a decrease in mortality due to coronary artery
      disease.

      Several studies had given preliminary evidence that regular administration of aspirin may be
      of benefit to patients with known coronary artery disease. A National Heart and Lung
      Institute-sponsored study, the Coronary Drug Project, ran a pilot trial of aspirin and
      placebo in men with previous myocardial infarctions. Preliminary results from this trial
      demonstrated its feasibility and led NHLBI to sponsor a more definitive controlled study of
      the benefit of aspirin in the secondary prevention of coronary heart disease.

      An Institute Planning Committee met four times between October 1974 and April 1975 and
      developed a protocol, manual of operations, and data collection forms. Recruitment of
      patients began in June 1975, with the first patient randomized on July 2, 1975. Patients who
      were randomized had been seen at the AMIS Clinical Center for two initial visits and one
      baseline visit and were free of any reasons for exclusion, such as the current use of
      anticoagulants and a history of adverse reactions to aspirin. Patients took acetaminophen at
      times when they would normally take aspirin.

      Follow-up was for a minimum of 3 years, with each patient seen at 4-month intervals and
      monitored for side effects and various nonfatal events, including cardiovascular problems.
      The primary endpoint was mortality. Annually, a detailed history was obtained and a complete
      physical examination performed. The study involved 30 clinical centers, a coordinating
      center, and a central laboratory.

      The study completed patient recruitment in the scheduled one year period. A total of 4,524
      post-MI patients were enrolled by the 30 clinical centers. Three-year minimum patient
      follow-up ended in August 1979.

      DESIGN NARRATIVE:

      Randomized, double-blind, fixed sample. Eligible patients were assigned to a treatment group
      receiving 1 gm of aspirin daily (the equivalent of three standard aspirin tablets) or to a
      control group receiving a placebo.
    

Intervention name(s): aspirin
Intervention type(s): Drug
Intervention MeSH terms: Aspirin
Allocation: Randomized
Masking: Double
Primary purpose: Prevention