LAA Closure vs Warfarin for Stroke Prevention in Atrial Fibrillation

A left atrial appendage closure device provided a similar level of stroke prevention to that of warfarin in patients with atrial fibrillation.

The use of the Watchman (Boston Scientific; St. Paul, Minnesota) left atrial appendage (LAA) closure device in nonvalvular atrial fibrillation (AF) provides stroke prevention similar to that of warfarin as well as greater reductions in bleeding risk and mortality, according to findings presented at TCT 2017, held October 29 to November 2 in Denver, Colorado.1

The results were simultaneously published in the Journal of the American College of Cardiology.2

Investigators analyzed patient data from the PROTECT AF (WATCHMAN Left Atrial Appendage System for Embolic Protection in Patients With Atrial Fibrillation; identifier: NCT00129545) and PREVAIL (Evaluation of the WATCHMAN LAA Closure Device in Patients With Atrial Fibrillation Versus Long Term Warfarin Therapy; identifier: NCT01182441) trials. PROTECT AF and PREVAIL investigators randomly assigned a total of 1114 patients with nonvalvular AF to either treatment with LAA closure or warfarin.

Among participants in the PREVAIL trial (n=407), investigators found a calculated 18-month rate of the first composite coprimary end point (systemic embolism [SE], stroke, or cardiovascular/unexplained mortality) of 0.066 and 0.051 for LAA closure and warfarin, respectively (95% credible interval, 0.78 to 2.13). This end point did not achieve noninferiority in PREVAIL (posterior probability for noninferiority=88.4%); however, the secondary coprimary end point (postprocedural ischemic stroke or SE) did achieve noninferiority (posterior probability for noninferiority=97.5%).

Data from the pooled meta-analysis demonstrated similarity between the 2 arms with regard to the composite end point (hazard ratio [HR]: 0.820; P =.27). In addition, both arms demonstrated similar all-stroke and SE outcomes (HR: 0.961; P =.87).

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The researchers observed significant differences in the rates of hemorrhagic stroke (HR: 0.20; P =.0022), all-cause death (HR: 0.73; P =.035), and postprocedural bleeding (HR: 0.48; P =.0003), with the data favoring LAA closure over warfarin.

According to the investigators, future studies should focus on comparing “the benefit of LAA occlusion against oral anticoagulants other than warfarin in patients with AF” while evaluating the benefits in patients with contraindications to anticoagulant therapy.


  1. Reddy VY, Doshi SK, Kar S, et al. 5-year outcomes after left atrial appendage closure: from the PREVAIL and PROTECT AF trials. Presented at: TCT 2017 Meeting; October 29-November 2, 2017; Denver, Colorado.
  2. Reddy VY, Doshi SK, Kar S, et al; on behalf of the PREVAIL and PROTECT AF investigators. 5-year outcomes after the left atrial appendage closure. From the PREVAIL and PROTECT AF trials [published online November 2, 2017]. J Am Coll Cardiol. doi:10.1016/j.jacc.2017.10.021