Abstract WP206: Short-Term Risk of Ischemic Stroke After Detection of Left Ventricular Thrombus on Cardiac Magnetic Resonance Imaging

Abstract

Introduction: The risk of ischemic stroke in patients with evidence of left ventricular (LV) thrombus on cardiac magnetic resonance imaging (MRI) is uncertain. Methods: We performed a retrospective cohort study of patients who underwent cardiac MRI for evaluation of cardiomyopathy or myocardial ischemia between 2007-2016. Using a departmental registry, we identified all hospitalized patients with cardiac MRI evidence of LV thrombus. In a 2:1 ratio, we created a random sample of hospitalized patients who underwent cardiac MRI for similar indications but had no evidence of LV thrombus. We compared the risk of stroke prior to hospital discharge among three groups of patients: (1) those with no evidence of LV thrombus, (2) those with LV thrombus by cardiac MRI but not by echocardiography, and (3) those with LV thrombus by both cardiac MRI and echocardiography. The chi-square statistic was used to compare rates of stroke among the three groups. Results: We identified 33 patients with evidence of LV thrombus on cardiac MRI and 66 patients without LV thrombus on cardiac MRI (mean age, 56.8 (±13.1) years). All patients underwent echocardiography. Patients with LV thrombus on cardiac MRI had a higher burden of myocardial infarction than patients without LV thrombus (21.4% versus 8.3%, P <0.001), but had similar ejection fractions (28.8% versus 31.1%, P = 0.34). Of the 33 patients with LV thrombus on cardiac MRI, 13 also had echocardiographic evidence of LV thrombus. Ischemic stroke prior to hospital discharge occurred in 0 of 66 (0%; 95% Confidence Interval [CI], 0-5.4%) patients without LV thrombus on cardiac MRI, 1 of 20 (5%; 95% CI, 0.1-24.9%) patients with LV thrombus on cardiac MRI but not echocardiogram, and 2 of 13 (15.4%; 95% CI, 1.9-45.4%) patients with LV thrombus by both cardiac MRI and echocardiography ( P value for comparison among groups, 0.01). Conclusions: We found a 5% short-term risk of ischemic stroke in patients with LV thrombus that was not seen on an echocardiogram but was detected on cardiac MRI.