WATCHMAN Device Implantation – Early Experience

It is currently estimated that in the United States, over 6 million people have atrial fibrillation (AF) and that this arrhythmia is responsible for 1 in 5 strokes in patients 80 years of age and older.¹ It is also currently accepted that, in non-valvular AF (NVAF), the vast majority of clots responsible for strokes originate from the left atrial appendage (LAA).^2-4 Chronic anticoagulation, either with warfarin or newer novel (thrombin or factor Xa inhibitors) agents, has become the standard of care for prevention of the thromboembolic complications of AF.⁵ Unfortunately, many patients cannot safely be anticoagulated due to bleeding risk. Based on data from two randomized clinical trials (PROTECT-AF⁶ and PREVAIL⁷), LAA occlusion with the WATCHMAN™ Left Atrial Appendage Closure Device (Boston Scientific) gained FDA approval in early 2015. A major consideration in the approval of this device, however, was the risk of its implantation. In the PROTECT-AF trial, a “learning curve” was noted with procedural complication rates being inversely related to operator experience. The following case relates observations from a busy, community-based hospital early in their WATCHMAN device experience.

Case Description

The patient is a 71-year-old female with a history of multiple traumatic falls, prior retroperitoneal bleed, and chronic atrial fibrillation. Five years prior, she suffered a spontaneous retroperitoneal bleed while on warfarin therapy. Her INR at that time was 2.4. Two months prior to the WATCHMAN procedure, she fell while walking up a flight of steps and suffered a large thigh hematoma while on a factor Xa inhibitor. Anticoagulation was discontinued and aspirin initiated. She then fell once again onto her knee, this time suffering only bruising. Both her calculated bleeding risk (HAS-BLED) and CHA₂DS₂-VASc scores were 3. Given her high risk for stroke and contraindications to anticoagulation, WATCHMAN device implantation was recommended.

As per our institution’s protocol, the patient underwent a screening transesophageal echocardiogram (TEE) to assess LAA anatomy and to determine WATCHMAN implantation feasibility. Figure 1 demonstrates an image from that study. The left atrial appendage displayed a “windsock” appearance with acceptable dimensions and was deemed to be suitable for WATCHMAN implantation.

The case was formally reviewed preoperatively with all members of the team including physicians and nurses. The device was implanted in a hybrid OR setting under general anesthesia. CT surgery backup was available. A radial arterial line and Foley catheter were inserted. Right femoral venous access was used for device deployment. A multidisciplinary approach involving the EP, interventional, echo, and anesthesia departments was utilized. As such, two operators (one EP and one cath physician) as well as one echo physician were present throughout. A TEE was performed intraoperatively, and guided the transseptal puncture and device deployment. A 24 mm device was successfully deployed (Figure 2). Doppler analysis detected no flow around the device. Sheaths were removed as dictated by serial ACT measurements. The patient was discharged the following day on warfarin and aspirin 81 mg daily.

Forty-five days later, the patient felt well and was without clinical complaints. A repeat TEE was performed (Figure 3) and confirmed that the device was well seated. Doppler analysis demonstrated minimal flow (2 mm jet, <5 mm acceptable) around the device. Based on these echo findings, warfarin was discontinued and the patient was discharged on clopidogrel and aspirin 325 mg daily. It is anticipated that clopidogrel will be discontinued 6 months post operatively. 

Discussion

Abington Hospital is a large community hospital outside of Philadelphia. We did not participate in the WATCHMAN clinical trials, and the procedure discussed here was our second implant. Currently, we are limiting cases to patients with ideal anatomy based on a screening TEE. As our experience grows, more challenging anatomy will likely be considered. These cases are performed in a hybrid OR setting utilizing a multidisciplinary team that includes nurses and physicians from EP, interventional cardiology, echo, and CT surgery. Based on our prior TAVR experience, we have found this collaborative approach to be extremely valuable. Each subspecialty brings unique “tips and tricks” that educate others and contribute to procedural safety and success. As far as the actual implantation is concerned, we have found it to be moderately challenging with its share of potential pitfalls. However, by employing a methodical and well thought-out team approach, procedure success has proven attainable, even early into our institution’s WATCHMAN experience.

Given the high success rate of device implantation as well as relatively low morbidity and mortality, we expect exponential growth in utilization of this device, especially in patients at high risk for bleeding on anticoagulation.

Disclosure: The author has no conflicts of interest to report regarding the content herein. Outside the submitted work, Dr. Borge reports speaker fees from Janssen, Bristol-Myers Squibb, and Boehringer Ingelheim.  

References

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3. Holmes DR, Reddy VY, Turi ZG, et al. Percutaneous closure of the left atrial appendage versus warfarin therapy for prevention of stroke in patients with atrial fibrillation: a randomized non-inferiority trial. Lancet. 2009;374:534-542.
4. Sievert H, Lesh MD, Trepels T, et al. Percutaneous left atrial appendage transcatheter occlusion to prevent stroke in high-risk patients with atrial fibrillation: early clinical experience. Circulation. 2002;105:1887-1889.
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6. Holmes DR, Reddy VY, Turi ZG, et al. Percutaneous closure of the left atrial appendage versus warfarin therapy for prevention of stroke in patients with atrial fibrillation: a randomized non-inferiority trial. Lancet. 2009;374:534-542.
7. Holmes DR Jr., Kar S, Price MJ, et al. Prospective randomized evaluation of the Watchman left atrial appendage closure device in patients with atrial fibrillation versus long-term warfarin therapy: the PREVAIL trial. J Am Coll Cardiol. 2014;64:1-12.