What is the efficacy and safety of devices for left atrial appendage (LAA) closure/litigation in atrial fibrillation (Afib) (AF)?

Updated: Nov 18, 2019
  • Author: Lawrence Rosenthal, MD, PhD, FACC, FHRS; Chief Editor: Jeffrey N Rottman, MD  more...
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Answer

The majority of embolic stroke in patients with nonvalvular atrial fibrillation (AF) are associated with left atrial appendage (LAA) thrombi. LAA closure may be a suitable alternative to long-term warfarin therapy for stroke prophylaxis in patients with nonvalvular AF. [141]  Currently available devices for LAA closure/ligation include the WATCHMAN device, WAVECREST device, AMPLATZER cardiac plug (ACP) or amulet, and LARIAT endocardial/epicardial suture. [142]

Two randomized trials have assessed the efficacy and safety of LAA closure using the WATCHMAN device. The PROTECT-AF (Left Atrial Appendage System for Embolic Protection in Patients with Atrial Fibrillation) trial randomized 707 patients with nonvalvular AF and at least one additional risk factor for stroke to either warfarin or LAA closure. [141] Patients who received the WATCHMAN device received 45 days of warfarin and aspirin therapy after implantation. If there was an adequate seal (ie, no leaks >5 mm around the device on TEE performed 45 days after implantation), patients were transitioned to aspirin and clopidogrel for 6 months, followed by lifelong aspirin .

The WATCHMAN device was found to be noninferior to warfarin therapy for the composite primary end-point of stroke, systemic embolism, and cardiovascular or unexplained death. [141] Furthermore, the risk of hemorrhagic stroke was significantly lower in group implanted with the WATCHMAN device compared to the group who received warfarin therapy. However, up to 5% of patients who received the WATCHMAN device developed serious pericardial effusions.

Due to this safety concern, the PREVAIL (Prospective Randomized Evaluation of the Watchman LAA Closure Device in Patients with Atrial Fibrillation Versus Long-Term Warfarin Therapy) trial was undertaken, in which only 2.2% of the participants developed pericardial effusion. [143] This trial randomized 407 patients to receive WATCHMAN device or warfarin therapy, wherein the presence of more than one risk factor for stroke was required, the mean CHADS2 score for the participants was 2.6, and 25% of the operators had to be new operators.

In a patient-level meta-analysis utilizing data from the PROTECT and the PREVAIL studies, as well as follow-up registry data (2406 patients with average duration of follow-up 2.7 years), Holmes et al reported that the WATCHMAN device was associated with a nearly 80% reduction in the risk of hemorrhagic stroke, and a 50% reduction in the risk of cardiovascular/unexplained death, when compared to warfarin therapy. [144] However, the risk of ischemic stroke with the WATCHMAN device was significantly higher than with warfarin therapy.

On the basis of the published trial data, the WATCHMAN device implantation seems to be reasonable alternative to warfarin therapy when there is contraindications for long-term anticoagulation with warfarin. Large clinical trials for the WAVECREST and AMPLATZER devices are under way.

As compared to the other three percutaneous LAA closure devices, LARIAT is an endocardial/epicardial suturing system for ligation of LAA. An epicardial approach is utilized to deliver a pretied suture over a snare, and this is facilitated by an endocardial magnetic-tip guide wire. In a multicenter series, major bleeding was reported in 9% of the patients who underwent LARIAT procedure. [145] However, unlike with the WATCHMAN device, there is no need for postprocedure anticoagulation. Larger studies with long-term follow-up to assess the efficacy and safety of LARIAT device are also under way.


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