Asymptomatic carotid artery stenosis and stroke risk in patients undergoing CABG.

Objective: Perioperative stroke associated with coronary artery bypass grafting (CABG) is a catastrophic event. Identification of patients at risk and reduction of its incidence remains of high importance. The aim of this study was to analyse the association of different degrees of asymptomatic carotid artery stenosis (CAS) with the perioperative outcome in a consecutive series of CABG patients and to identify predictors for CABG associated ischaemic stroke.

Methods: In total, 2727 patients undergoing isolated CABG procedure at the Medical University of Innsbruck between 2010 and 2020 were included in this study. Sonography data included the severity of carotid stenosis for left and right internal carotid artery individually. The primary outcome was the 30-day stroke and mortality rate, and the secondary outcome was 5-year mortality. A Cox regression model was performed after adjustment for EuroSCORE II.

Results: Left CAS>50% was present in 177 patients (7%) and right CAS>50% in 197 patients (7.8%). In total, 1.6% (40 patients) of the patients died within 30 days after surgery, and 1.0% (24 patients) experienced a postoperative stroke within 30 days. Patients with a carotid stenosis>90% had a higher 30-day mortality (p<0.001) and higher incidence of postoperative stroke within 30 days (p=0.005). Patients with a history of a prior stroke were at higher risk of experiencing another stroke within 30-days after surgery, with an HR of 6.829 (2.811-16.589) (p<0.001).

Conclusions: Asymptomatic CAS>90% and history of stroke are both independent risk factors for perioperative stroke and 30-day mortality.