WATCHMAN Device Implantation in Clinical Practice

Atrial fibrillation (AF) is one of the most common abnormal heart rhythms in the United States. It is estimated between 3 to 6 million Americans suffer from AF, and as the U.S. population ages, this will only increase. Along with its other symptoms, AF is a leading cause of stroke in the U.S. due to its high risk of thrombus development. Over 90-95% of the thrombus formation in the left atrium occurs within the left atrial appendage. Multiple clinical trials have demonstrated that anticoagulation therapy, with either warfarin or a novel oral anticoagulant, is effective in reducing stroke risk. However, in a subset of patients, anticoagulation is contraindicated due to bleeding or other risks. The recently approved WATCHMAN Left Atrial Appendage Closure Device (Boston Scientific) is indicated to reduce the risk of thromboembolism from the LAA in patients with non-valvular AF who are at increased risk for stroke and systemic embolisms based on CHADS₂ or CHA₂DS₂-VASc scores and are recommended for anticoagulation therapy. Patients whom their physicians deem to be suitable for warfarin and have an appropriate rationale to seek a non-pharmacologic alternative to warfarin, taking into account the safety and effectiveness of the device compared to warfarin, are potential candidates for the therapy. The WATCHMAN was first implanted in Europe in 2005, and approved for use by the U.S. FDA in March 2015. HealthEast St. Joseph’s Hospital of St. Paul was the first hospital in the Twin Cities to offer this novel technique in the management of stroke reduction due to AF. The WATCHMAN team at St. Joseph’s Hospital is made up of nursing coordinators, nurse practitioners, imaging cardiologists, and electrophysiologists. A collaborative, team-based approach is used to maximize patient outcomes and limit complications.

Case Description

The patient is a 79-year-old female with a past history of atrial fibrillation status post pulmonary vein isolation procedure. She has had mild recurrence post her ablation. She has a CHA₂DS₂-VASc score of 6 (age > 75, female gender, hypertension, history of arterial emboli due to AF). Unfortunately, she has had great difficulty staying within the target INR range of 2-3, along with significant bleeding complications due to supratheraputic INR. 

After discussion of risks and benefits, she wished to proceed with WATCHMAN device implantation in an attempt to come off anticoagulation  while also mitigating her high stroke risk. She was maintained on warfarin throughout the intraoperative period, and on the day of procedure, her INR was 2.4. 

The procedure was performed in our EP laboratory. The team consisted of 2 electrophysiologists and an imaging cardiologist. The patient was under general anesthesia throughout the procedure, and transesophageal echocardiogram (TEE) imaging was used during the entire procedure. Access was obtained in the right and left femoral veins, along with arterial hemodynamic monitoring via the left femoral artery. An intracardiac echo (ICE) catheter was introduced through the left femoral vein for transseptal puncture. 

Transseptal puncture was performed in the standard fashion utilizing ICE and fluoroscopy. Prior to transseptal puncture, heparin bolus and infusion were initiated to maintain a target ACT of >300 seconds. Once the left atrium was accessed, sizing of the WATCHMAN device was performed by TEE and angiographic imaging to evaluate the ostium (base) and depth of the left atrial appendage. We require an appropriate size to depth ratio in order to appropriately fit a WATCHMAN device. Once an appropriately sized device is chosen, it is positioned under fluoroscopy and TEE visualization. The device fit is evaluated by TEE for appropriate compression, depth, and flow, and a final angiography confirms placement. If the fit is deemed good, a “tug test” is used to confirm device stability. Once positioning is confirmed, the device is released from its delivery system. Follow-up TEE imaging confirmed no evidence of effusion or other complications, and sheaths were pulled. The patient was extubated without difficulty and was discharged home the following day after an uneventful night in the hospital. At 6-week follow-up, the patient’s warfarin was discontinued after TEE confirmed good device location and no significant leak. The patient was placed on aspirin and clopidogrel to complete 6 months of therapy.

Summary

The WATCHMAN device is the first implantable device approved by the FDA to reduce the risk of thromboembolic events from the left atrial appendage without the need for long-term anticoagulation in patients with non-valvular atrial fibrillation. The WATCHMAN device has been extensively studied in 2 randomized clinical trials and 2 registry studies, including 2400 patients and over 6000 patient-years of data. 

The PROTECT AF study enrolled 707 patients from 59 centers around the world, and evaluated non-inferiority to warfarin. Patients were evaluated at time of enrollment, along with 3-, 6-, 9-month follow-ups, and annual follow-ups thereafter. Non-inferiority to warfarin was confirmed by this study, and post-hoc analysis demonstrated the WATCHMAN was superior to warfarin in the composite endpoint of all stroke, cardiovascular or unexplained death, and systemic embolism (2.4% vs 3.8%). This showed a 40% relative risk reduction. 

Since FDA approval, select hospital systems within the United States with experienced implanters have been chosen as initial sites for WATCHMAN commercial release. With recent CMS coverage approval, WATCHMAN implants are expected to increase dramatically in the coming years.

Disclosures: The author has no conflicts of interest to report regarding the content herein. Outside the submitted work, Dr. Krauthammer reports receiving personal fees from St. Jude Medical.

References

1. PROTECT AF Study. Boston Scientific. Available online at https://bit.ly/1htb2v8. Accessed June 20, 1016.
2. 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 randomised non-inferiority trial. Lancet. 2009;374(9689):534-542.
3. 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):1-12.
4. WATCHMAN LAA Closure Technology – P130013. U.S. FDA. Published April 2, 2015. Available online at https://tinyurl.com/ovbecrq. Accessed June 20, 1016.