Preoperative noninvasive coronary risk stratification in candidates for carotid endarterectomy.

BACKGROUND AND PURPOSE

Patients with symptomatic carotid stenosis who are candidates for carotid endarterectomy are at high short- and long-term risk of coronary events. To stratify patients at different risk of coronary events we investigated the usefulness of a noninvasive preoperative cardiological workup.

METHODS

We studied 172 consecutive patients admitted to the Neurosurgical Department for symptomatic high-grade (70% to 99%) carotid stenosis (age, 42 to 74 years; mean, 57.8 years). Patients without history of coronary artery disease (CAD) and able to exercise were submitted to exercise electrocardiographic testing (EET) and, if abnormal, to exercise thallium myocardial imaging (TMI). Patients were classified into four groups: group 1, patients without CAD: no history of CAD, normal EET, or normal TMI in the presence of indeterminant EET (n = 93, 54%); group 2, patients with silent CAD: no history of CAD and concordant abnormal EET and TMI (n = 28, 16%); group 3, patients unable to exercise: no history of CAD and inability to perform adequate EET because of previous stroke or claudication (n = 29, 17%); and group 4, patients with known CAD: history of angina or myocardial infarction (MI) (n = 22; 13%).

RESULTS

The four groups were comparable in regard to age, sex, and computed tomographic scan of the brain. The prevalence of stroke was higher in patients unable to exercise; hypercholesterolemia was more frequent in patients with known CAD. During the perioperative period (< or = 30 days after carotid endarterectomy), coronary events occurred in 3 patients (2%): fatal MI in 2 patients in group 4 and 1 patient in group 3. One hundred percent of patients were followed up for 6.2 years. Coronary events occurred in 23 of the 168 patients discharged from the hospital (13.7%); these were fatal in 11 (6.5%): 3 patients of group 1 (3%; sudden death in 2, fatal MI in 1), 8 patients of group 2 (29%; fatal MI in 5, unstable angina in 3), 8 patients of group 3 (28%; fatal MI in 4, nonfatal MI in 4), and 4 patients of group 4 (18%; fatal MI in 2, sudden death in 1, unstable angina in 1). Kaplan-Meier estimated curves of survival free from fatal and nonfatal coronary events were 97%, 51%, 49%, and 59%, respectively (P < .001, group 1 versus groups 2 and 3; P < .01, group 1 versus group 4).

CONCLUSIONS

Among patients undergoing carotid endarterectomy, coronary events occurred twice as often as cerebral recurrences. A preoperative noninvasive cardiac investigation, including EET, can adequately identify groups of patients with diverse short- and long-term prognoses. In addition to patients with known CAD, those with silent CAD or who are unable to exercise represent, without the need of further investigation, groups at high risk of coronary events in long-term follow-up.