Impact of left atrial appendage closure on left atrial function: insights from the OCEAN-LAAC registry

Abstract Background Percutaneous left atrium appendage closure (LAAC) is an effective therapy to prevent thromboembolic events among patients with atrial fibrillation (AF) (Ref 1). However, since the left atrium appendage (LAA) potentially serves as a part of the left atrium (LA) volume and a buffer for increasing LA pressure, this procedure may impair LA compliance (Ref 2). Purpose In this study, we sought to investigate the effect of LAAC on LA function. Methods/Results The OCEAN-LAAC registry is an ongoing, multicentre Japanese registry including patients who underwent LAAC in Japan (Ref 3). Among 225 patients from the registry, LA volume index (LAVI) and tricuspid regurgitation pressure gradient (TRPG) at baseline and 6 months after the procedure were analysed. In the overall population, no significant increase in LAVI (Abstract Picture 1A) and TRPG (Abstract Picture 1B) was observed (LAVI baseline vs 6 months, 55.0 [44.0, 70.0] ml/m2 vs 55.0 [42.0, 75.6] ml/m2; P = 0.31; TRPG, 25.0 [20.3, 32.0] mmHg vs 25.0 [20.0, 32.0] mmHg; P = 0.85). However, particular patients underwent an increase in LAVI (Abstract Picture 1C), and multivariable analysis showed smaller LAVI and elevated TRPG at baseline, rather than any procedural factors, were significantly associated with an increase in LAVI (Odds ratio (OR) for baseline LAVI: 0.98 [95% confidential interval (CI): 0.97 - 0.996]; OR for baseline TRPG: 1.04 [95% CI: 1.00 - 1.08]). A 5 ml/m2 increase in LAVI at a 6-month follow-up was significantly associated with subsequent heart failure hospitalization (HFH) (Hazard ratio: 3.37 [95% CI: 1.18 - 9.65]) (Abstract Picture 2A). However, this predictive value was not observed in patients with lower LAVI (≤ 55 ml/m2) at baseline; instead, it was observed in those with a baseline LAVI over 55 ml/m² (Abstract Picture 2B). Conclusions In summary, our study did not elucidate the negative impact of LAAC on LA function, yet demonstrated an increase in LAVI at 6 month follow-up was frequently observed in patients with lower LAVI and higher TRPG at baseline. Additionally, increase in LAVI was significantly associated with subsequent HFH, which was more evident in patients with higher LAVI at baseline.