Use of Novel Left Atrial Appendage Closure Device in Case of Difficult Left Atrial Appendage Anatomy

Introduction

Atrial fibrillation (AF) is the most common arrhythmia seen in clinical practice. Current literature indicates that the overall prevalence of AF is in the range of 1-2% of the general population. Its prevalence is expected to double in the next 50 years as the population continues to grow older.¹ Patients with atrial fibrillation are at a significantly increased risk of stroke when compared to those with normal heart rhythms. The left atrial appendage is the most important source of thromboembolism and stroke in patients with non-valvular atrial fibrillation. Left atrial appendage occlusion (LAAO) is increasingly being used as a safe and effective alternative to oral anticoagulation in patients with atrial fibrillation and high bleeding risk.² The WATCHMAN FLX (Boston Scientific) is among the newest generation of the LAAO devices, and offers several new enhanced features over the previous generation. Here we describe a patient with difficult LAA anatomy that was overcome using the WATCHMAN FLX, when the older-generation device could not be implanted.³

Case Description

A 70-year-old male presented with a history of persistent atrial fibrillation and high bleed risk. His CHA₂DS₂-VASc score was 3 and his HAS-BLED score was 4. The patient was seeking an alternative to anticoagulation; hence, a shared decision was pursued and he was approved for an LAAO device. The patient had a difficult LAA anatomy consistent with a short chicken wing morphology with a prominent ridge in the mid-portion (Figure 1). Transesophageal (TEE) measurements taken at 0, 45, 90, and 135 degrees revealed a maximum ostium of 25 mm and a minimum ostium of 16 mm. Initially, a 27 mm original WATCHMAN device was inserted into the LAA. After deployment, the ridge of the device was extruding out of placement (Figure 2). After several attempts with different sheath shapes and transseptal puncture sites, the procedure was aborted.

The patient was brought back 2 weeks later, and an attempt with the WATCHMAN FLX was made. We obtained a higher transseptal access using the single-curve WATCHMAN TruSeal Access System. Using the desheathing/advancement technique, the LAAO device was extruded and advanced into position. With the WATCHMAN FLX device, we were more easily able to maneuver within the LAA. Initial deployment showed a posterior shoulder likely secondary to the ridge in the mid-portion of the LAA. The device was recaptured, then desheathed and deployed more posteriorly bypassing the prominent ridge and advanced into the distal portion of the LAA. After confirming position and tug test, there was no leak and the device was released (Figure 3).

Discussion

In recent years, LAAO has become an appealing alternative to reduce the risk of stroke in patients with non-valvular atrial fibrillation (NVAF) who cannot tolerate long-term anticoagulation with vitamin K antagonists or novel oral anticoagulation (NOAC). Several studies, including PROTECT-AF and PREVAIL, have demonstrated non-inferiority in the prevention of stroke with WATCHMAN LAAO when compared to warfarin therapy, with lower rates of non-procedural bleeding and mortality. More recently, the PINNACLE FLX study evaluated performance of the WATCHMAN FLX device as an alternative to oral anticoagulation therapy, including non-vitamin K antagonist oral anticoagulants (NOACs), for stroke risk reduction in patients with NVAF. The trial met its primary safety endpoint defined as occurrence of a major procedure-related complication within 7 days. The trial also met its primary effectiveness endpoint with a 100% rate of effective LAA closure at 12 months with peri-device flow of <5 mm. The impressive performance demonstrated in the PINNACLE FLX trial can be attributed to the novel design of the new WATCHMAN FLX. This design comes with a greater number of struts, a closed distal end to lessen the likelihood of perforation, dual-row anchors to reduce the risk of embolization, and reduced metal exposure. It can also be fully recaptured and repositioned. The WATCHMAN FLX has demonstrated superiority over its predecessor, the first-generation WATCHMAN device. Still, uncertainty exists as to what all this means in terms of risk of stroke. This is being evaluated in the CHAMPION-AF and CATALYST trials. These randomized trials will evaluate OAC-eligible patients undergoing LAA closure with the LAAO versus DOAC. Future studies will need to investigate periprocedural complications and success rates in higher risk patients as well as in lower volume centers.^5-8

Summary

In this unique case, initial deployment showed a posterior shoulder likely secondary to the ridge in the mid-portion of the LAA. With the enhanced features of the WATCHMAN FLX, we were able to fully recapture and reposition, then desheath and redeploy the device more posteriorly. This feature of full recapture and redeployment is unique to the WATCHMAN FLX, and allowed us to bypass the prominent ridge and advance into the distal portion of the LAA for more precise positioning.

The new, fully rounded design of the WATCHMAN FLX makes it easier and safer for physicians to maneuver within the LAA, facilitating optimal placement and long-term stability. The device has a wider range of sizes than the previous device and can treat a wider range of patient anatomies. It also has the ability to be fully recaptured, repositioned, and redeployed for more precise placement. Many of these new enhancements of the WATCHMAN FLX were utilized in this case. These new features help further minimize device embolization and the risk of periprocedural complications, such as pericardial effusion. We were also more easily able to maneuver within the LAA with the WATCHMAN FLX. 

Disclosures: The authors have no conflicts of interest to report regarding the content herein.

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