Optimizing The Utilization Of Cardiac Magnetic Resonance Imaging Among Patients With Ischemic Stroke

Background: The current AHA guidelines recommend (class IIb) advanced cardiac imaging in an embolic stroke of unknown source (ESUS). We aim to better characterize the role of cardiac MRI (cMRI) in the evaluation of stroke patients and determine patient characteristics that may increase the positive predictive value of cMRI. Method: A retrospective review of stroke patients at a comprehensive stroke center, who had cMRI between 12/2016 and 11/2020 was conducted using institutional registries. Ischemic stroke patients with ESUS, cryptogenic (with ESUS as a competing etiology), and cardioembolic etiologies were included. Cases with TIA, large vessel, small vessel, or hemodynamic etiologies were excluded. Cardioembolic etiology was defined as newly diagnosed Afib patients with TTE abnormalities including wall motion abnormalities and/or reduced LVEF <50%, stroke while compliant with anticoagulation for known Afib, or among whom the timing of restarting anticoagulation was in question. TTE and cMRI results from all cases were reviewed for remarkable findings, most notably intracardiac thrombus, and analyzed if a change in anti-thrombotic therapy was directly attributable to cMRI results. Results: As per our criteria, 250 cases (Female 44.4%, Black 29.6%, Age mean: 65.2 years) were included, of whom 146 (58.4%) were ESUS, 86 (34.4%) were cryptogenic, and 18 (7.2%) were cardioembolic. Sixteen (6.4%) revealed intracardiac thrombus, of which 10 had LV thrombus, 5 had LA thrombus, and 1 had RA thrombus along with questionable PFO on cMRI. Of these, 14 (87.5%) had an escalation of anti-thrombotic therapy. For the other 2 cases, despite cMRI obtained due to low LVEF and revealing LA thrombus, antithrombotic regimen was not changed. Eight (3.2%) additional patients were placed on anticoagulation secondary to incidental findings. Conclusion: In this large retrospective analysis of 250 select stroke cases, escalation of anti-thrombotic therapy from anti-platelets to full dose anti-coagulation was indicated in 14 patients (5.6%) with addition of cMRI. Further analysis of data is in process to determine the subset of stroke patients who would benefit the most from cMRI.