Original title: Percutaneous Left Atrial Appendage Closure for Stroke Prophylaxis in Patients With Atrial Fibrillation: 2.3-Year Follow-up of the PROTECT AF (Watchman Left Atrial Appendage System for Embolic Protection in Patients With Atrial Fibrillation) Trial. Reference: Vivek Y. Reddy et al. Circulation. 2013;127:720-729.
Atrial fibrillation is the most common sustained arrhythmia in the world and its importance lies in the risk of ischemic stroke (CVA). Anticoagulation is effective in preventing strokes but has difficulty in being sustained over time and also brings the risk of bleeding. The LAA is the main site of thrombus formation that occurs in cardioembolic stroke in fibrillated patients.
The hypothesis of this study was that the Watchman appendage closure device, (Atritech, Inc, Minneapolis, MN), would be not inferior to warfarin in fibrillated patients. Inclusion criteria were of course, the permanent nonvalvular atrial fibrillation associated with at least one additional risk factor for stroke, (age ≥ 75 years, hypertension, diabetes, heart failure, history of stroke or transient ischemic attack or systemic embolism), and the absence of contraindications to anticoagulation. The primary efficacy endpoint was the occurrence of any stroke, (ischemic or hemorrhagic), systemic embolism, cardiovascular death including security related events to the procedure, (cardiac tamponade, periprocedural stroke and device embolization), and major bleeding. We included a total of 707 randomized patients 2:1 to appendage closure or warfarin. Mean follow-up was 2.3 ± 1.1 years. 34% of patients had to discontinue warfarin, at least temporarily, mainly due to invasive studies (58%) or for bleeding (17%). Of the 463 patients to receive this device, 408 (88%) were successfully implanted.
The primary efficacy endpoint was observed at 3% per year for the branch appendage closure versus 4.3% per year for the warfarin branch, (RR 0.71; CI 0.44-1.3; chance for non-inferiority > 0.999). Efficacy was consistent across all subgroups of patients. With respect to safety, the device showed more events compared to warfarin, (5.5% per year versus 3.6% per year), mostly because of events that occurred early.
The Watchman atrial appendage closure device was not inferior to warfarin in preventing stroke, cardiovascular death or systemic embolism in patients with chronic atrial fibrillation. On the other hand, branch for closing the appendage presented an increase in the number of security events, mainly related to the procedure. Once successfully implemented, the above device was superior to well controlled anticoagulation with warfarin.
This work, like every one comparing an invasive procedure with medical treatment, must overcome the initial occurrence of periprocedural events. In this case we add that patients who received the device continued anticoagulation protocol for 6 months and then 6 months of dual antiplatelet therapy with the risk of bleeding. We would expect that after the first year, the bleeds anticoagulation branch start to offset the periprocedural events of the device branch.