DETERMINANTS OF THE USE OF CORONARY ANGIOGRAPHY AND REVASCULARIZATIONAFTER THROMBOLYSIS FOR ACUTE MYOCARDIAL-INFARCTION

Background Clinical trials and practice guidelines have identified cli nical criteria for the use of coronary angiography and revascularizati on procedures after thrombolysis for acute myocardial infarction. The effect of these criteria on clinical practice has not been extensively evaluated. Methods We used classification-and-regression-tree (CART) and logistic-regression models to study the patients in the first Glob al Utilization of Streptokinase and Tissue Plasminogen Activator for O ccluded Coronary Arteries trial, to identify the variables that best p redicted the use of angiography and revascularization procedures after thrombolysis. Results Among the 21,772 U.S. patients in the trial, 71 percent underwent coronary angiography before discharge from the hosp ital. Of these, 58 percent underwent revascularization (73 percent rec eiving angioplasty). The CART model for the use of angiography showed that age was the Variable most predictive of angiography; only 53 perc ent of patients at least 73 years of age underwent angiography, as com pared with 76 percent of those under 73. Among the older patients, age was again the most predictive factor; among the younger patients, the availability of angioplasty was a more important predictor (67 percen t of patients in hospitals without angioplasty facilities underwent an giography, as compared with 33 percent in hospitals with such faciliti es). The next most important variable was recurrent ischemia, which wa s more predictive at hospitals without an gioplasty facilities than at those with them. Both statistical models identified coronary anatomy as the most important predictor of the use and type of revascularizati on. Conclusions More patients treated with thrombolysis underwent angi ography and revascularization before discharge than might be expected. Younger age and the availability of the procedures appeared to be the major determinants of the use of coronary angiography, whereas corona ry anatomy largely determined the use and type of revascularization. T his process appeared to select low-risk patients for intervention rath er than those at higher risk, who would be the most likely to benefit. (C) 1996, Massachusetts Medical Society.