Even the Tiniest Leaks Matter in Left Atrial Appendage Occlusion

By Amit Goyal, MD - Last Updated: January 11, 2024

Transcatheter left atrial appendage occlusion (LAAO) is a safe and effective alternative to systemic anticoagulation to prevent strokes in select patients with nonvalvular atrial fibrillation (AF). A meta-analysis encompassing over 60,000 patients found that peri-device leak (PDL) on transesophageal echocardiography (TEE) is both common and dangerous, adding a critical caveat to shared decision-making when considering this catheter-based approach1.

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Stroke is a potentially devastating complication of atrial fibrillation. While systemic anticoagulation with oral anticoagulants provides potent prophylaxis, their use is limited by bleeding consequences. The 2023 ACC/AHA/ACCP/HRS atrial fibrillation guidelines recommend considering percutaneous LAAO in patients with AF who have a moderate to high risk of stroke (CHA2DS2-VASc score ≥2) and a contraindication to long-term oral anticoagulation due to a nonreversible cause (COR 2a, LOE B)2. They also give a Class 2b recommendation to consider percutaneous LAAO as an alternative to oral anticoagulation based on patient preference and informed shared decision-making in AF patients with moderate to high risk of stroke and a high risk of major bleeding on oral anticoagulation (LOE B). These guidelines were based on high procedure success rates, excellent procedural safety profile, and comparable efficacy for stroke prevention when compared with oral anticoagulation, yet with lower bleeding events. However, efficacy for stroke prevention is predicated on the complete exclusion of the left atrial appendage (LAA), the major source of systemic emboli in nonvalvular AF.

Samaras and colleagues evaluated the consequences of residual PDL in a meta-analysis of 48 studies encompassing a total of 61,666 patients treated with percutaneous LAAO – mean age of 72.2 (+/- 4.2) years, mean CHAD2DS2-VASc score of 4.0 (+/- 0.6), mean HAS-BLED score of 2.8 (+/- 0.9), and mean percentage of women of 40%. TEE found PDL of any size in over 1 in 4 patients (26.1%), whereas computed tomography angiography (CTA) found LAA patency or PDL in over half of patients (54.9% and 57.3%, respectively). PDL by TEE was associated with adverse outcomes, whereas neither LAA patency nor PDL by CTA conferred prognostic significance. TEE-based PDL of any size significantly increased the risk of thromboembolism [pooled odds ratio (pOR) 2.04; 95% confidence interval (CI) 1.52-2.74], all-cause mortality (pOR 1.16; 95% CI 1.08-1.24), and major bleeding (pOR 1.12; 95% CI 1.03-1.22). Importantly and in contrast to previously held beliefs, the presence of even very small PDLs by TEE was found to be problematic, with a graded effect based on PDL size. For any PDL of >0, >1, >3, and >5mm, the pORs for thromboembolism were 1.82 (95% CI 1.35-2.47), 2.13 (95% CI 1.04-4.35), 4.14 (95% CI 2.07-8.27), and 4.44 (95% CI 2.09-9.43), respectively, compared with either no PDL or PDL smaller than each cut-off.

These findings debunk the widely advocated yet arbitrary cut-offs of 3-5 mm for determining clinically significant leaks and guiding antithrombotic treatment. The prognostic significance of even sub-mm PDL mandates nuanced procedural planning. Strategies to optimize percutaneous LAAO results include detailed 3-dimensional imaging planning (CTA provides greater anatomic resolution than TEE here), proper device sizing to ensure adequate compression for an effective seal, multi-device availability, and strategic transeptal puncture to allow coaxial engagement. Importantly, deeper device positioning to prevent PDL should be avoided due to the increased risk of device-related thrombus, another important mechanism for thromboembolism. Post-implantation strategies include longer anti-thrombotic medical treatment, TEE over CTA imaging surveillance, enhanced surveillance beyond the 45-day post-implantation imaging, and a lower threshold for PDL closure.

Systemic anticoagulation remains the first-line standard of care for stroke prevention in patients with atrial fibrillation. Percutaneous LAAO has emerged as a safe and effective alternative for carefully selected patients. But as Samaras and colleagues have shown here, even the tiniest PDL should be avoided to maximize benefits. These results teach us that, when planning, implanting, and surveilling percutaneous LAAO, every detail matters.

References

  1. Samaras A, Papazoglou AS, Balomenakis C, et al. Residual leaks following percutaneous left atrial appendage occlusion and outcomes: a meta-analysis. Eur Heart J. Published online December 13, 2023. doi:10.1093/eurheartj/ehad828
  2. Joglar JA, Chung MK, Armbruster AL, et al. 2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation. Published online November 30, 2023. doi:10.1161/CIR.0000000000001193

 

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