Abstract 2620: MDCT is Highly Accurate in Identifying and Excluding Left Atrial Appendage Filling Defects in Patients with Atrial Fibrillation Undergoing Radiofrequency Pulmonary Vein Antral Isolation
Introduction: Patients with atrial fibrillation (AF) referred for radiofrequency pulmonary vein antral isolation (PVAI) undergo multi-detector CT (MDCT) for pre- and post-procedure assessment of pulmonary veins. MDCT demonstrates incomplete mixing of CT contrast and blood (filling defects), consistent with significant spontaneous echo contrast (SEC) or thrombus which confers a higher thromboembolic risk. We sought to assess accuracy of MDCT with transesophageal echocardiography (TEE) as the gold standard in detecting thrombus or significant SEC in such patients.
Methods: We retrospectively identified 226 consecutive patients (mean age 57±10 years, 81% males) undergoing PVAI for AF who had MDCT and TEE performed within 7 days of each other. Imaging was performed using low osmolar contrast (90 –100 cc) on 16 or 64 (1–1.5 mm slice thickness) detector MDCT scanners (Siemens Sensation, Erlangen, Germany). Filling defects reported in LAA on MDCT and presence of at least moderate SEC or thrombus on TEE (defined as positive findings) were independently confirmed.
Results: Of the group, 83 (37%) patients had hypertension, 31 (14%) had coronary artery disease, 18 (8%) had history of stroke, 157 (69%) had dilated LA (> 4mm) and 30 (13%) had ejection fraction <50%. Fifty (22%) patients had a filling defect in LAA on MDCT and 36 (16%) patients had at least moderate SEC or thrombus on TEE. The sensitivity, specificity, positive predictive, and negative predictive value for MDCT detection of at least moderate SEC or thrombus were 92%, 91%, 66%, and 98% respectively (Table⇓). Of the 3 false negative patients on MDCT, all had SEC while none had LAA thrombus as documented by TEE.
Conclusions: In patients with AF undergoing PVAI, MDCT accurately identifies and excludes moderate SEC or thrombus in LAA. MDCT cannot conclusively differentiate between significant SEC and thrombus. Patients with a “clean” LAA detected by MDCT, can potentially safely undergo PVAI without additional testing.