6.1 LAA Occlusion: Will the Latest Tools and Techniques Help Us Overcome the Barriers?

These proceedings summarize the educational activity of the 16th Biennial Meeting of the International Andreas Gruentzig Society held January 31-February 3, 2022 in Punta Cana, Dominican Republic

Faculty Disclosures     Vendor Acknowledgments

2022 IAGS Summary Document

Statement of the problem or issue

Transcatheter left atrial appendage (LAA) occlusion as a field has matured over the past decade, with clinical trials and registries like PROTECT-AF, PREVAIL, PRAGUE-17, PINNACLE-FLX, and the Amulet IDE study showing progressively improving safety and efficacy profiles that approach or exceed oral anticoagulation. Yet, current LAA occlusion technology is not perfect, with persistent leak rates, rare but persistent device-associated thrombus (DAT), and not all LAA anatomies are favorable for device implant. It has become clear that device leaks, regardless of size, are associated with less effective protection from stroke, and, while it remains unclear if this is confounded or causal, the field now acknowledges that complete elimination of leak is the goal. Additionally, now that even small leaks are thought to be significant, methods for detecting and measuring leaks, including the more sensitive computed tomography angiography (CTA), have not been standardized. Questions remain about comparing leaks between different device designs, including plugs and lobe-with-disc configurations. Additionally, the optimal antiplatelet and anticoagulant (AC) regimen remains unclear, and may not be uniform for all patients. Post implant, oral AC use reduces DAT, but many patients have relative or absolute contraindications to oral AC. Given the results of the ACTIVE-W trial showing no difference in bleeding between DAPT and oral AC, much controversy remains regarding the roll of DAPT in high bleeding risk patients. Recent data suggest half-dose apixaban monotherapy is associated with lower bleeding and DAT rates, although this remains an off-label use. Finally, antithrombotic coating of LAA devices has been proposed as another strategy to reduce DAT, and this is under development and investigation.

Gaps in knowledge

Given that leaks of all sizes are associated with higher stroke rates, should we be plugging or coiling leaks when they are observed, and how would we study this? Will steerable guides improve outcomes? Are our current devices good enough, or do we need transformational technology both to address anatomic challenges and to abolish leaks? Are antithrombotic coatings a game changer or a gimmick? How do we study this? How do we figure out the optimal postimplant pharmacologic regimen? Can intracardiac echocardiography (ICE) for precise ­device placement and confirming absence of leak be the future, or will this negatively impact ­implant quality? Does 4-dimensional (4D)-ICE change the calculus?

Possible solutions and future directions

The CHAMPION-AF and CATALYST clinical trials are randomizing Watchman-FLX and Amulet devices, respectively, with non-vitamin K oral anticoagulants (NOAC). These 2 trials will answer many important questions in the field of LAA occlusion, including whether LAA closure will become a first-line option in atrial fibrillation (AF)-related stroke prevention. LAAOS-3, an RCT of surgical LAA closure, showed incremental reduction in strokes even though most patients continued oral AC, perhaps suggesting a synergistic effect. A LAAOS-4 trial has been proposed to study LAA occlusion using Watchman-FLX with or without oral AC, to further test this hypothesis. Regardless, for high bleeding risk patients, the field desperately needs more data on optimal antiplatelet and anticoagulant regimens post implant. Antithrombotic device coatings may change this, and therefore it may be prudent to wait on more definitive clinical trials until after completion of current device iteration. Exciting new transformational LAA occlusion technology has been proposed, which might reduce the device “footprint,” resulting in a nothing-left-behind scenario. These disruptive technologies may change the field, but they will require further study. ­Finally, procedural evolution to a less invasive procedure not using general anesthesia, with ICE guidance instead of transesophageal echocardiography (TEE), is becoming more common in clinical practice. Limitations in visualization with currently available 2-dimensional ICE technology risks compromising procedural quality with more residual device leaks. Next-generation 4D-ICE has imaging quality on par with TEE and may dramatically narrow the trade-offs, but will require operators to become skilled in procedural image guidance.