Influence of coronary heart disease on morbidity and mortality after carotid endarterectomy: a population-based study in Olmsted County, Minnesota (1970-1988)

Abstract

To evaluate the prognostic importance of coronary artery disease among patients undergoing carotid endarterectomy, 177 residents of Olmsted County, Minnesota who underwent carotid endarterectomy during the period 1970 through 1988 were followed up to July 1, 1989. Patients were stratified as to the presence (n = 64) or absence (n = 93) of overt coronary artery disease or prior myocardial revascularization (n = 20) at the time of endarterectomy. At 30 days after carotid endarterectomy, there were no significant differences between patients with or without coronary artery disease in the occurrence of death, myocardial infarction or stroke. Kaplan-Meier estimate of 8-year relative survival after carotid endarterectomy (assessed as a percent of survival in age- carotid endarterectomy (assessed as a percent of survival in age- and gender-matched control subjects) was 89% in those without and 75% in those with overt coronary artery disease. Of the 59 total deaths, 29 (49%) had a cardiac cause and 4 (7%) were due to stroke (p less than 0.0001). The cumulative incidence of a cardiac event at 8 years after carotid endarterectomy was greater in those with than in those without overt coronary artery disease (61% vs. 25%, p less than 0.0001). In multivariable analysis, uncorrected coronary artery disease and diabetes were the only independent predictors of subsequent cardiac events, whereas age was the only independent predictor of death. These population-based data suggest that carotid endarterectomy can be safely undertaken in patients with stable coronary artery disease. In long-term follow-up of these patients, coronary rather than cerebral vascular disease is the most frequent cause of morbidity and mortality. Thus, these data lend strong support to the concept of early identification and management of coronary artery disease in patients undergoing carotid endarterectomy.