Asymptomatic Cardiac Ischemia Pilot
Objectives:
To assess the feasibility of and test the methodology
for a full-scale clinical trial of therapies for asymptomatic cardiac ischemia.
Background:
Asymptomatic cardiac ischemia, frequently designated
as silent myocardial ischemia, refers to episodes of objectively demonstrable
transient ischemia in the absence of symptoms. 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.
Subjects:
Men and women, with coronary artery disease documented
angiographically, who had evidence of ischemia on both stress (exercise)
testing and 48-hour ambulatory electrocardiogram monitoring (AECG) and were
amenable to revascularization. The 618 patients, stratified by presence or
absence of angina, included 94 women (15%) and 524 men (85%), with 14 percent
minorities.
Design:
A total of 1,959 patients were screened by AECG
monitoring; 49 percent had asymptomatic ischemia. The 558 patients whose data
are in the data set were randomized to one of the three treatment strategies:
183 to angina-guided medical strategy with titration of anti-ischemic
medication to relieve angina; 183 to angina-guided plus AECG ischemia-guided
medical strategy with titration of anti-ischemic medication to eliminate both
angina and AECG ischemia; and 192 to revascularization by angioplasty or bypass
surgery. The primary outcome was the absence of ischemia at twelve weeks.
Results:
Twelve-week, one year and two year follow up results
have been published. Two-year follow-up results of patients randomized to
initial strategies of medical therapy versus revascularization were published
in Circulation in April, 1997 (Davies R.F., Goldberg A.D., Forman, S., et al.:
Asymptomatic Cardiac Ischemia (ACIP) Study Two-Year Follow-Up: Outcomes of
Patients Randomized to Initial Strategies of Medical Therapy versus
Revascularization. Circulation 1997 95:2037-2043). Two years after
randomization, the total mortality was 6.6 percent in the angina-guided drug
therapy strategy (n=183), 4.4 percent in the ischemia-guided drug therapy
strategy (n=183) , and 1.1 percent in the revascularization strategy (n=192).
The rate of death or myocardial infarction was 12.1 percent in the
angina-guided strategy, 8.8 percent in the ischemia-guided strategy, and 4.7
percent in the revascularization strategy. The authors concluded that a
strategy of initial revascularization appeared to improve the prognosis of this
population compared with angina-guided medical therapy.
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Study Website |
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Study Documentation |
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Data Distribution Agreement |
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