Percutaneous Left Atrial Appendage Closure for Stroke Prophylaxis in Patients With Atrial Fibrillation: 2.3 Year Follow-Up of the PROTECT AF Trial
What is the long-term efficacy of left atrial appendage (LAA) closure, including in patients with prior thromboembolism, the group at highest risk for recurrent stroke?
Patients (n = 707) with nonvalvular atrial fibrillation (AF) and at least one risk factor (age >75 years, hypertension, heart failure, diabetes, or prior stroke/transient ischemic attack) were randomized to either the Watchman device (n = 463) or continued warfarin (n = 244) in a 2:1 ratio. After device implantation, warfarin was continued for approximately 45 days, followed by clopidogrel for 4.5 months and lifelong aspirin. Differences in event rates over time were assessed using the Kaplan-Meier method.
Study discontinuation rates were 15.3% (71/463) and 22.5% (55/244) for the Watchman and warfarin groups, respectively. The time in therapeutic range for the warfarin group was 66%. The composite primary efficacy endpoint included stroke, systemic embolism, and cardiovascular death, and the primary analysis was by intention-to-treat. After 1,588 patient-years of follow-up (mean 2.3 ± 1.1 years), the primary efficacy event rates were 3.0% and 4.3% (percent per 100 patient-years) in the Watchman and warfarin groups, respectively (relative risk [RR], 0.71; 95% confidence interval [CI], 0.44-1.30%/year), meeting the criteria for noninferiority (probability of noninferiority >0.999). There were more primary safety events in the Watchman group (5.5%/year; 95% CI, 4.2-7.1%/year) than in the control group (3.6%/year; 95% CI, 2.2-5.3%/year; RR, 1.53; 95% CI 0.95-2.70).
The authors concluded that the strategy of LAA closure is noninferior to systemic anticoagulation with warfarin.
This study reports that long-term efficacy of ‘local’ therapy with the Watchman LAA closure device was noninferior to systemic treatment with warfarin. AF patients at greatest risk for cardioembolic events, the ‘secondary prevention’ patients who previously sustained an embolic event, also appear to receive sustained benefit from the LAA closure strategy. It should be noted that the LAA closure arm did sustain an increased number of procedure-related safety events, mainly pericardial tamponade and procedure-related stroke. Additional long-term real-world data will help further define the role of this device in patients with AF.
Keywords: Stroke, Follow-Up Studies, Ischemic Attack, Transient, Warfarin, Risk Factors, Ticlopidine, Atrial Function, Left, Thromboembolism, Blood Coagulation, Secondary Prevention, Atrial Appendage, Heart Failure, Confidence Intervals, Hypertension, Diabetes Mellitus, Cardiac Tamponade
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