The presence of spontaneous echo contrast didn't increase the risk for left atrial appendage closure: A propensity score matching analysis based on the CLACBAC study

Background: Left atrial appendage closure (LAAC) was effective in preventing thromboembolic events and stroke in patients with atrial fibrillation (AF). However, whether left atrial spontaneous echo contrast (LA-SEC) poses a higher risk for thromboembolism is contradictory. We aimed to investigate whether LA-SEC is a risk factor for thromboembolic events in patients who underwent LAAC. Methods: 258 consecutive patients who underwent successful LAAC were enrolled and divided according to the presence or absence of LA-SEC detected by transesophageal echocardiography (TEE). Propensity score matching (PSM) was used to eliminate covariate imbalances. Baseline characteristics, periprocedural details, and clinical outcomes were compared between LA-SEC and non-LA-SEC groups and PSM-matched groups. Results: Of the 258 patients enrolled, mean age was 71.8 +/- 8.3 years and 59.3 % were male. LASEC group had a higher percentage of persistent AF and worse cardiac function. No significant difference in peri-procedure parameters was found. Through follow-up of 38.1 +/- 10.7 months, the total incidence of thromboembolic events and stroke was 7.8 % and 6.6 %, respectively. Though the event-free survival rate of thromboembolic events (Log-Rank P = 0.042) and stroke (Log-Rank P = 0.010) was significantly lower in the LA-SEC group, multivariable COX regression analysis showed LA-SEC was not an independent predictor of thromboembolic events (Hazard ratio 2.073, 95% Confidence interval 0.845-5.082, P = 0.111). Further survival analysis between PSM-matched groups with comparable baseline characteristics presented no significant difference in survival free from thromboembolic events (Log-Rank P = 0.616) and stroke (Log-Rank P = 0.312). Conclusion: Patients with LA-SEC had worse condition, while LA-SEC per se did not increase the incidence of thromboembolic events and stroke for patients who underwent LAAC.