Prognostic impact of increase in left atrial volume following left atrial appendage closure: Insights from the OCEAN-LAAC registry

Background: Percutaneous left atrial appendage closure (LAAC) is an effective therapy to prevent thromboembolic events among patients with atrial fibrillation (AF). However, since the left atrial appendage (LAA) contributes to left atrial volume and serves as a buffer for increasing left atrial pressure, this procedure may impair left atrium (LA) compliance, enlarge LA, and deteriorate diastolic function. In this study, we sought to investigate the change in left atrial volume index (LAVI) following LAAC and its effect on prognosis. Methods and Results: We analyzed 225 patients from the OCEAN-LAAC registry, an ongoing, multicenter Japanese study. Comparing LAVI measurements at baseline and 6 months after LAAC, no significant increase was observed (55.0 [44.0, 70.0] ml/m² vs. 55.0 [42.0, 75.6] ml/m²; P = 0.31). However, some patients underwent LAVI increase. Particularly, a smaller LAVI (odds ratio [OR]: 0.98 [95 % confidence interval (CI): 0.97–0.996]) and elevated tricuspid regurgitation pressure (TRPG) at baseline (OR: 1.04 [95 % CI: 1.00 – 1.08]) were significantly related to the increase in LAVI at 6-month follow-up. In addition, a 5 ml/m² increase in LAVI was significantly associated with subsequent heart failure hospitalization (HFH) (hazard ratio: 3.37 [95 % CI: 1.18–9.65]). This association, however, was not observed in patients with lower baseline LAVI (≤55 ml/m²) but was only seen in those with a baseline LAVI over 55 ml/m². Conclusion: Our study demonstrated an increase in LAVI after LAAC was related to smaller LAVI or elevated TRPG at baseline. The LAVI increase was significantly associated with subsequent HFH.