Cardiac CT To Detect Cardiac Thrombi In Patients With Acute Ischemic Stroke: A Substudy Of Mind The Heart

Background: Cardiac thrombi are a major risk factor for ischemic stroke. We used cardiac CT to assess the prevalence of cardiac thrombi in acute ischemic stroke patients. Methods: This was a substudy of Mind the Heart, a prospective single-center cohort study in which consecutive adult patients with acute ischemic stroke underwent prospective ECG-gated cardiac CT during the initial stroke imaging protocol. Patients also underwent routine stroke work-up, including transthoracic echocardiography (TTE). Patients were included from May 2018 to November 2020. We compared patients with a cardiac thrombus on CT (defined as filling defect <100 Hounsfield’s Units) to those without a cardiac thrombus. Outcomes were functional outcome on the modified Rankin scale (mRS) and ischemic stroke recurrence at 90 days. Results: Of 452 included patients, cardiac CT detected 40 thrombi in 38 (8%) patients. Thrombi were located in the left atrial appendage in 31 (7%), left atrium in 2 (0.4%) and left ventricle in 7 (2%) patients. TTE, performed in 25 patients with a cardiac thrombus (median time CT to TTE 1 day), detected a thrombus in 2 patients (0.4%, both left ventricle thrombi). Patients with a cardiac thrombus more frequently had a history of atrial fibrillation (40% vs 15%), used anticoagulation (42% vs 16%), had a large vessel occlusion (58% vs 41%), had intracranial occlusions in multiple vascular territories (5% vs 0.5%) and had a higher baseline NIHSS (17 [IQR 6-22] vs 5 [IQR 2-3]). In total, 26/38 (68%) patients with a cardiac thrombus had a history of atrial fibrillation or had atrial fibrillation diagnosed during stroke work-up. At 90 days, 19/23 (83%) patients with a cardiac thrombus who were alive were treated with anticoagulation. Patients with a cardiac thrombus had worse functional outcome (median mRS 4 [IQR 2-6] vs 2 [IQR 1-4], p<0.01) and non-significantly more often had a recurrent ischemic stroke (8% vs 5%,p=0.61) than patients without a cardiac thrombus. Conclusion: Cardiac CT detected a cardiac thrombus in 1 in every 12 patients with acute ischemic stroke. These thrombi were rarely detected with TTE. Patients with cardiac thrombi more often had atrial fibrillation and severe neurological deficits. Functional outcome was worse in patients with cardiac thrombi.