Incidence and Distribution of Cerebral Embolism After Cardiac Surgery According to the Systemic Perfusion Strategy　― A Diffusion-Weighted Magnetic Resonance Imaging Study

Background:Stroke is a major concern in minimally invasive cardiac surgery, so we investigated the incidence and risk factors of cerebral embolism according to the systemic perfusion strategy under thorough imaging assessment.Methods and Results:Between November 2011 and May 2015, 315 cardiac surgery patients who underwent preoperative computed tomography angiography (CTA) as a routine evaluation were enrolled. The incidence and distribution of cerebral embolism were analyzed with routine postoperative brain diffusion-weighted magnetic resonance imaging (DW-MRI) examination. Anterograde perfusion was used in 103 patients (group A), and retrograde perfusion was performed in 212 patients (group R). Operative deaths, incidence of clinical stroke (group A: 0%, group R: 0.5%, P=0.77), and rate of cerebral embolism (group A: 35.9%, group R: 26.4%, P=0.08) were comparable. The median number of new embolic lesions detected by MRI per patient (group A: 2, group R: 2, P=0.16), maximal diameter of the lesion (group A: 6.5 mm, group R: 6.0 mm, P=0.97), and anatomic distribution of the lesion were similar between groups. In the multivariate analysis, hypertension, emergency status, atherosclerosis grade 3 or 4 (intimal thickening >4 mm), and cardiopulmonary bypass time were independent risk factors for postoperative cerebral embolism, but retrograde perfusion was not.Conclusions:According to the results of postoperative DW-MRI, retrograde perfusion itself might not increase the incidence of postoperative cerebral embolism in properly selected cardiac surgery patients undergoing routine preoperative CTA examination.