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

OBJECTIVES: 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).

METHODS: 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.

RESULTS: 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 was associated 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.

CONCLUSIONS: 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.

CLINICAL TRIAL REGISTRATION: https://clinicaltrials.gov. Unique identifier: NCT02319083.