Asymptomatic Cardiac Ischemia Pilot (ACIP) Study
Condition: Cardiovascular Diseases; Coronary Disease; Heart Diseases; Myocardial Ischemia
MeSH terms: Cardiovascular Diseases; Heart Diseases; Coronary Disease; Myocardial Ischemia; Ischemia
Study type: Interventional
Phase: Phase 3

Summary: 
      To assess the feasibility of and test the methodology for a full-scale clinical trial of
      therapies for asymptomatic cardiac ischemia.
    

Detailed description: 
      BACKGROUND:

      Asymptomatic cardiac ischemia, frequently designated as silent myocardial ischemia, refers to
      episodes of objectively demonstrable transient ischemia in the absence of symptoms. Annually,
      more than one million patients suffer acute myocardial infarction. Of the approximately
      700,000 who are discharged alive from the hospital, as many as 180,000 will be asymptomatic
      but have evidence of myocardial ischemia on a pre-discharge exercise test. Asymptomatic
      ischemia has been linked with sudden death or myocardial infarction. It is estimated that in
      the United States over six million patients have chronic, symptomatic coronary heart disease
      and up to three million of these may exhibit transient asymptomatic myocardial ischemia.
      Asymptomatic ischemia is thought to be present in the majority of coronary heart disease
      patients with stable angina pectoris, over 70 percent of all ischemic episodes being
      asymptomatic. Asymptomatic ischemia following myocardial infarction or in the presence of
      chronic stable angina may be associated with substantially increased morbidity and mortality

      Traditionally, treatment of patients with coronary heart disease has been given for and
      guided by patients' symptoms. There was a growing trend toward recognizing asymptomatic
      cardiac ischemia and according it importance equal to that of symptomatic ischemia. Many
      physicians believed that suppression of asymptomatic ischemia in patients with coronary heart
      disease would reduce morbidity and mortality. This was leading to rapidly increasing and
      widespread applications of both medical and revascularization therapies.

      In 1989, there was a lack of knowledge as to the relative efficacy of different treatment
      strategies to control asymptomatic cardiac ischemia. Given the estimated high prevalence of
      asymptomatic cardiac ischemia in patients with coronary heart disease and evidence of
      increased risk of untoward outcome, the public health problem was of sufficient magnitude to
      warrant a pilot study to determine to what extent asymptomatic ischemia could be controlled.
      If the pilot study demonstrated feasibility, a full-scale clinical trial would then be
      considered to evaluate the impact of effective treatment of asymptomatic ischemia on survival
      and cardiovascular morbidity in patients with coronary heart disease.

      DESIGN NARRATIVE:

      A total of 1,959 patients were screened by AECG monitoring; 49 percent had asymptomatic
      ischemia, and 65 percent were enrolled in the study. The 618 patients were randomized to one
      of the three treatment strategies: 202 to angina-guided medical strategy with titration of
      anti-ischemic medication to relieve angina; 202 to angina-guided plus AECG ischemia-guided
      medical strategy with titration of anti-ischemic medication to eliminate both angina and AECG
      ischemia; and 212 to revascularization by angioplasty or bypass surgery. Patients able to
      take either beta-adrenergic blocking agents or calcium antagonists were also randomized to
      receive one of two medical combination regimens: atenolol plus nifedipine or diltiazem plus
      isosorbide dinitrate. Those who could be treated with only one regimen, such as asthmatic
      patients, were assigned to the appropriate regimen. The primary outcome was the absence of
      ischemia at twelve weeks. Recruitment ended in January 1993. Clinical based follow-up was
      completed for 18 months and survival status free of MI was completed for 24 months
    

Intervention name(s): atenolol; nifedipine; diltiazem; isosorbide dinitrate; coronary artery bypass coronary artery bypass; angioplasty, transluminal, percutaneous coronary
Intervention type(s): Drug; Drug; Drug; Drug; Procedure; Procedure
Intervention MeSH terms: Atenolol; Diltiazem; Nifedipine; Isosorbide; Isosorbide Dinitrate; Isosorbide-5-mononitrate
Allocation: Randomized
Primary purpose: Treatment