Abstract WP273: Radiologic Characteristic of Perioperative Large Vessel Occlusions in Patients Who Underwent Transcatheter and Surgical Valve Replacement

Abstract

Body Introduction: Ischemic stroke is a known perioperative complication of both transcatheter and surgical aortic valve replacement (TAVR and SAVR). We compared large vessel occlusions (LVO) in ischemic strokes after TAVR and SAVR to those of spontaneous ischemic strokes) and examined radiographic characteristic of their occlusive clots. Methods: Between January 2012 to December 2017, 9069 patients underwent TAVR or SAVR at a single tertiary center. Perioperative stroke was defined as a stroke that occurred within14 days of surgery. Exclusions were presence of extracorporeal membrane oxygenation and ventricular assist devices, as well as concurrent cardiac procedures except coronary revascularization. LVOs were detected using CTA or MRA, defined as internal carotid, middle cerebral, basilar or posterior cerebral artery occlusions. The site of occlusion was matched to its location on non-contrast CT brain. Control occlusions were LVOs of cardio embolus and large artery atherosclerosis from a single-center stroke registry. Tissue density of occlusive clots was measured in Hounsfield Unit (HU). We compared clot densities of perioperative LVOs to control LVOS. Results: Of 157 patients with perioperative stroke during the study period, 107 met inclusion criteria for analysis. LVO represented 16.8% (n=18) of perioperative strokes in patients who underwent TAVR or SAVR. Frequencies of LVOs were similar between TAVR (6/28, 21.4%) and SAVR (12/79, 21.4%, p=0.45). Occlusions involved ICA in 5 patients, M1 MCA in 8, M2 in 3, P1 PCA in 1, and basilar in 1. Clot density could be measured in 15 patients. Clots from perioperative LVOs were more dense than clots of LVOs from patients with known cardioembolism (median 53.5 HU in perioperative, 40 HU in cardioembolism, p<0.001), but were similar to LVOs due to large artery atherosclerosis (median 55.5 HU, p=0.57). Four perioperative LVOs were noted to be exceptionally dense (mean 226.8 HU, SD= 59) and separated themselves from others in regard to clot density on CT. Conclusion: The heterogeneity of LVOs can be appreciated on CT brain because of differences in clot density. These differences may be helpful in determining stroke etiology.