Effect of untreated carotid artery stenosis at the time of isolated coronary artery bypass grafting.

Background: Severe carotid artery stenosis (sCAS) is frequently discovered at the time of evaluation for coronary arterial revascularization. However, there has been controversy regarding the optimal management of sCAS. This study evaluated the potential effects of untreated sCAS at time of coronary artery bypass grafting (CABG) in contemporary practice. Methods: This was a retrospective study from a multihospital healthcare system including patients undergoing isolated CABG between 2011 and 2018. Patients were stratified by the presence of sCAS (≥80% stenosis) in at least 1 carotid artery. Perioperative and 5-year stroke were compared, and multivariable analysis was used to identify risk-adjusted predictors of stroke and mortality. Results: A total of 5475 patients were included, 459 (8.4%) with sCAS and 5016 (91.6%) without sCAS. Patients with sCAS experienced more frequent perioperative stroke (4.4% vs 1.2%; P < .001), with most attributable to ischemic or embolic etiologies. The median duration of follow-up was 4.6 years (interquartile range, 3.0-6.5 years). One-year and 5-year survival were both lower in patients with sCAS (P < .001). In multivariable analysis, sCAS was associated with increased risk-adjusted hazard for both mortality (hazard ratio [HR], 1.28; 95% confidence interval [CI], 1.02-1.60; P = .030) and stroke (HR, 1.76; 95% CI, 1.20-2.59; P = .004). The strongest risk-adjusted predictor for stroke was a previous history of stroke (HR, 2.51; 95% CI, 1.77-3.55; P < .001). Conclusions: This contemporary analysis of CABG procedures reveals that concurrent sCAS continues to confer a significant stroke risk, especially in those with history of previous stroke. Although whether sCAS lesions are responsible for most strokes is unclear, they likely serve as a surrogate for other stroke risk factors.