The influence of clinical risk factors on the use of angiography and revascularization after acute myocardial infarction. Myocardial Infarction Triage and Intervention Project Investigators

Abstract

Background: Coronary revascularization provides the greatest survival advantage in those patients with the greatest mortality risk. This study examines the relationship between variables that predict mortality and the use of angiography and revascularization after acute myocardial infarction.

Methods: Study of 4823 survivors of acute myocardial infarction, who underwent angiography between 6 hours and 5 days of admission, to determine the relationship between factors that predict mortality and the use of angiography (n = 2274), angioplasty (n = 692), and bypass surgery (n = 469).

Results: Except for recurrent angina, clinical factors that predict higher mortality were associated with a lower use of angiography (the multivariable adjusted odds ratio was 0.47 for older age, 0.85 for a history of infarction, 0.50 for patients not receiving thrombolytic medications, 0.64 for new heart failure, and 2.75 for recurrent angina [P < .001 for all factors]). A similar relationship was observed among patients selected for angioplasty (the odds ratio was 0.51 for an ejection fraction of < 40%, 0.72 for those patients not receiving thrombolytic medications, 0.74 for a history of infarction, and 1.94 for recurrent angina [P < .001 for all factors]). In contrast, patients with unfavorable prognostic profiles were much more likely to undergo coronary bypass surgery (the odds ratio was 1.46 for recurrent angina, 1.28 for older age groups, 2.23 for new heart failure, 1.28 for patients not receiving thrombolytic medications, and 1.46 for a history of infarction [P < .001 for all factors]).

Conclusions: These data suggest that aside from symptoms of recurrent angina, the use of angiography and angioplasty is not driven by mortality risk stratification. In contrast, bypass surgery is preferentially performed in patients at increased risk for mortality.