Pulsed Field Ablation of the Left Atrial Appendage Before Mechanical Closure to Reduce Peri-Device Leak (STUN-AF).

BACKGROUND

Left atrial appendage (LAA) closure (LAAC) is plagued by late peri-device leak. We posited that appendage contraction prevents full LAA seal, so conversely, LAA stunning with pulsed field ablation (PFA) of the LAA (left atrial appendage ablation [LAAA]) might promote rapid appendage thrombosis/obliteration.

OBJECTIVES

This study aims to assess the impact of LAAA during concomitant procedures on eliminating leaks.

METHODS

At 3 centers, consecutive patients undergoing concomitant PFA and LAAC also underwent LAAA or did not undergo LAAA, at operator discretion. Initial (∼3-4 months) (29% transesophageal echocardiography/71% computed tomography) and 12-month imaging were compared with a primary composite outcome of LAA patency, defined as either detectable flow into the LAA or evidence of echo-free space/contrast medium behind the device.

RESULTS

Among 317 total patients undergoing PFA and LAAC, including 222 patients who underwent LAAA and 95 who did not (control patients), all underwent initial imaging and 126 reached 12-month imaging follow-up. Device compression was 28% with LAAA vs 25% without LAAA (P < 0.001). Implantation success was 100%. The periprocedural adverse event rate was 2% in both groups. The primary composite outcome of LAA patency was significantly reduced with LAAA vs no-LAAA, both at 3-4 months (29% vs 64%; P < 0.001) and at 12 months (4% vs 42%; P < 0.001). Device-related thrombus rates were low and similar (2.3% vs 3.2%; P = 0.7). A validation subset including only patients with alternating LAAA assignment (LAAA: n = 59; no-LAAA: n = 63) again revealed that LAAA was associated with reduced LAA patency (3-4 months: 34% vs 51%; P = 0.06; 12 months: 8% vs 36%; P = 0.2). Final LAA e' velocity was significantly different between groups (17 ± 7 vs 34 ± 16 cm/s; P < 0.001), with higher velocity associated with LAA patency (P < 0.001).

CONCLUSIONS

PFA of the LAA has potential to reduce LAA patency during device-based LAAC.