Comparative study of cardiac magnetic resonance imaging and transesophageal echocardiography in detection of left atrial and left atrial appendage thrombi

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background Left atrial (LA) thrombi are the most common intracardiac masses. Left atrial appendage (LAA) is the most common site for thrombus formation in patients with atrial fibrillation (AF), and in patients with valvular lesions. Transesophageal echocardiography (TEE) has been the conventional investigation for thrombus detection. However, because TEE is a semi-invasive technique; a completely non-invasive technique would be of great concern. Purpose The aim of this study is to evaluate the feasibility and diagnostic performance of cardiac magnetic resonance imaging (CMR), for the assessment of thrombi in the left atrium and left atrial appendage (LA/ LAA). Also whether CMR is comparable to TEE in identification and measurement of thrombus size. Methods We studied 43 patients who were diagnosed to have LA/LAA thrombus, or highly suspected thrombus by TEE. They underwent multisequence CMR for assessment of thrombus detection; within 7 days of TEE performance. Data collected from CMR study were statistically analyzed to evaluate for sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV) and overall accuracy of detection of LA/LAA thrombus using TEE as the gold standard. Also agreement between both imaging techniques was assessed using kappa agreement coefficient. We conducted a questionnaire where 10 questions were asked to every patient in the study. It aimed to obtain an idea about patients’ opinion of both tests. Results During the study period of 13 months, 43 patients were assessed. Twenty one patients had AF and 22 patients were in sinus rhythm. The median CHA2DS2VASc score of AF patients was 2.52 ± 1.12, and 76.7% of patients were undergoing anticoagulation therapy. In all subjects, the LAA was readily visualized with CMR. When evaluating the diagnostic performance of CMR results revealed overall sensitivity, specificity, PPV, NPV and accuracy of 97.44%, 75%, 97.44%, 75% and 95.35% respectively. Results of questionnaire was statistically significant p value yielding good overall opinion for the sake of CMR. There was an additional role for CMR regarding tissue characterization; where CMR detected 3 cases, diagnosed by TEE as thrombus, 1 case revealed Libman-Sacks Endocarditis and 2 cases revealed fibroelastoma. This made a paradigm shift in patient management. Conclusion CMR is a noninvasive, feasible and comparable modality for thrombus detection in the LA and LAA and could be a reasonable, more comfortable alternative to TEE.