Stroke after Cardiac Valve Replacement: Distribution, Etiology, and Risk Factors (S47.002)

OBJECTIVE: To identify the mechanisms of stroke after cardiac surgery. BACKGROUND: Stroke is a potential complication of cardiac surgery. Predictors of stroke mechanisms are not well characterized, and their understanding may lead to improved stroke prevention for surgical patients. DESIGN/METHODS: We performed a retrospective analysis of data from a prospective observational cohort study of patients >65 years old undergoing aortic valve replacement (AVR) for calcific aortic stenosis. 129 post-operative brain MRIs with diffusion-weighted imaging (DWI) were reviewed, acute infarcts were classified by 2 raters as watershed, embolic, both, or neither, using pre-specified definitions. Predictors of embolic and watershed infarction were evaluated using univariable logistic regression. RESULTS: 79 of 129 patients (61[percnt]) had post-operative acute infarct on MRI. Mean age was 75 (±6) years, 66[percnt] male, 7[percnt] nonwhite. Clinical stroke was identified in 20 (16[percnt]). There was excellent interrater agreement on assessment of infarct type (κ =0.93). Embolic strokes only were identified in 60 (46[percnt]), watershed only in 2 (2[percnt]), both in 17 (13[percnt]), and no infarct in 50 (39[percnt]). Internal carotid artery (ICA) stenosis 蠅70[percnt] was associated with a watershed pattern (OR=7.4, 95[percnt] CI 1.3-41.1, p=0.04). Moderate-to-severe aortic arch atheroma was associated with embolic infarct (OR 3.5, 95[percnt] CI 1.08-11.3, p=0.04) but not ascending (p=0.36) or descending aortic atheroma (p=0.49). The presence of old white matter infarcts was associated with an increased likelihood of embolic (OR=5.0, 95[percnt] CI 1.5-16.8, p=0.009) but not watershed infarct (p>0.99). Drop in blood pressure from baseline to intra-operative nadir did not predict watershed or embolic infarct. CONCLUSIONS: The principal mechanism of acute ischemic infarct on MRI after AVR is embolism. Prior white matter infarct and moderate-to-severe aortic arch atheroma are predictive of embolic infarct. ICA stenosis 蠅70[percnt] is a predictor of watershed infarct and these patients may benefit from higher intraoperative blood pressure goals. Disclosure: Dr. Massaro has nothing to disclose. Dr. Messe has received personal compensation for activities with GlaxoSmithKline as a consultant. Dr. Messe has received research support from WL Gore and GlaxoSmithKline. Dr. Acker has nothing to disclose. Dr. Kasner has nothing to disclose. Dr. Torres has nothing to disclose. Dr. Fanning has nothing to disclose. Dr. Giovannetti has nothing to disclose. Dr. Ratcliffe has nothing to disclose. Dr. Bilello has nothing to disclose. Dr. Szeto has nothing to disclose. Dr. Bavaria has nothing to disclose. Dr. Hargrove III has nothing to disclose. Dr. Mohler III has nothing to disclose. Dr. Floyd has nothing to disclose.