Prognostic Impact of Asymptomatic Carotid Artery Stenosis in Patients Undergoing Coronary Artery Bypass Grafting

Abstract

The aim of this study was to evaluate the prognostic impact of untreated asymptomatic carotid artery stenosis (CS) in patients undergoing isolated coronary artery bypass grafting (CABG). This was a post hoc analysis of data from a prospective multicentre observational study. Patients without history of stroke or transient ischaemic attack from the multicentre E-CABG registry who were screened for CS before isolated CABG were included. Among 2813 patients screened by duplex ultrasound and who did not undergo carotid intervention for asymptomatic CS, 11.1% had a stenosis of 50-59%, 6.0% of 60-69%, 3.1% of 70-79%, 1.4% of 80-89%, 0.5% of 90-99%, and 1.1% had carotid occlusion. In the screened population post-operative stroke occurred in 25 patients (0.9%), with an incidence of 1.5% among patients with CS≥50% (n=649). Pre-operative screening had not found a relevant CS in 15 of 25 patients suffering stroke after CABG. Brain imaging identified cerebral ischaemic injury in 20 patients, which was bilateral in five patients (25%), ipsilateral to a CS≥50% in six (30%), and ipsilateral to a CS≥70% in three (15%). In univariable analysis, the severity of CS wasassociated with a significantly increased risk of stroke (CS<50%, 0.7%; 50-59%, 1.0%; 60-69%, 0.6%; 70-79%, 1.2%; 80-89%, 5.1%; 90-99%, 7.7%; occluded, 6.7%, p<.001). In multivariable analysis, a CS of 90-99% (OR 12.03, 95% CI 1.34-108.23) and the presence of an occluded internal carotid artery (OR 8.783, 95% CI 1.820-42.40) were independent predictors of stroke along with urgency of the procedure, severe massive bleeding according to the E-CABG classification, and the presence of a porcelain ascending aorta. Among screened patients with untreated asymptomatic patients, CS≥90% was an independent predictor of post-operative stroke. As this condition has a low prevalence and when left untreated is associated with a relatively low rate of stroke, pre-operative screening of asymptomatic CS before CABG may not be justified. https://clinicaltrials.gov. Unique identifier: NCT02319083.