Aortic valve replacement with or without coronary artery bypass grafting: stroke outcomes and predictors

Abstract

Background: Stroke is arguably the most important and devastating non-mortality complication after cardiac surgery, including comparisons between aortic valve replacement (AVR) and transcatheter aortic valve implantation. We analysed the rates and predictors of stroke after AVR with or without concurrent coronary artery bypass grafting (CABG). Methods: All patients undergoing AVR+/-CABG at Auckland City Hospital during 2005-2012 were included, and analyses conducted to identify predictors for post-operative stroke, defined as in-hospital new neurological deficits lasting more than 24 hours after surgery. Results: There were 620 isolated AVR and 450 AVR+CABG patients studied. Rates of stroke was significantly higher for AVR+CABG 3.3% (15) compared to AVR alone 1.3% (8), P=0.031. Independent predictors of stroke (odds ratio and 95% confidence interval) for isolated AVR included age (1.02, 1.00-1.04), syncope (6.07, 1.03-35.8), critical pre-operative state (6.07, 2.08-25.6) and history of stroke (7.23, 1.20-43.6), while the only independent predictor identified for AVR+CABG was diabetes on insulin (6.19, 1.63-23.5). Receiver-operative characteristics analysis found the original EuroSCORE having the highest C-statistic for detecting stroke after isolated AVR 0.845 (0.783-0.907), while the Society of Thoracic Surgeon's Score had the highest though moderate C-statistic after AVR+CABG 0.642 (0.508-0.776). Conclusion: Although rates of stroke are low at our centre, performing CABG concurrently with AVR was associated with significantly higher risk. We have identified a number of conventional cardiovascular risk factors that independently predict stroke in aortic valve surgery which should be taken into consideration when deciding for modality of aortic valve intervention.