Cardiac MRI Has Limited Additional Yield in Cryptogenic Stroke Evaluation (P1.225)

Objective: We hypothesized that cardiac magnetic resonance imaging (cMRI) would identify potential cardio-aortic sources of embolism missed by transesophageal echocardiography (TEE) in patients with cryptogenic stroke (CS). Background: CS accounts for 25-33[percnt] of ischemic strokes in modern stroke registries. The added yield of cMRI to identify cardio-aortic sources not detected by TEE has not been previously reported. Methods: We performed retrospective chart review at a single institution from 1/1/2009 to 3/1/2013 to identify consecutive adults with ischemic stroke or TIA who had both TEE and cMRI during index hospitalization. cMRI studies underwent independent, blinded review by 2 investigators. We first applied the well-validated Causative Classification System for ischemic stroke (CCS) to all subjects, blinded to cMRI results; then reapplied CCS using cMRI results to determine reclassification rates. Results: 96 patients met inclusion criteria. Without cMRI results, 66 (68.8[percnt]) were categorized as CS: 14 "undetermined unknown" and 52 "cardio-aortic embolism possible". The remainder (n=30) had probable or determined stroke causes: 20 evident cardio-aortic embolism, 4 lacunar, 4 large vessel disease, and 2 other defined causes. With cMRI results, 6 (9.1[percnt]) subjects with CS were reclassified. Among those initially “undetermined unknown”, cMRI results reclassified 4 subjects, 3 to "cardio-aortic embolism possible" and 1 to "cardio-aortic embolism probable". Among subjects classified as “cardio-aortic embolism possible”, 2 were reclassified as "evident cardio-aortic embolism" due to detection of vegetations, fibroelastoma, and/or complex aortic atheroma by cMRI. Conclusions: The addition of cMRI to TEE in the diagnostic evaluation of CS results in 9[percnt] reclassification of CCS subtype, with only 3[percnt] reclassified as a non-CS subtype. Our results indicate the need for cost-effectiveness studies assessing the role of cMRI in determining ischemic stroke etiology. Disclosure: Dr. Liberman has nothing to disclose. Dr. Kalani has nothing to disclose. Dr. Aw-Zoretic has nothing to disclose. Dr. Sondag has nothing to disclose. Dr. Daruwalla has nothing to disclose. Dr. Furiasse has nothing to disclose. Dr. Carr has nothing to disclose. Dr. Collins has nothing to disclose. Dr. Prabhakaran has received personal compensation for activities with the American Heart Association.