Long-Term Data Reported From Continued Access Registries of Boston Scientific’s Watchman LAAC Device
December 2, 2019—Findings from continued access registries on the long-term safety and efficacy of the Watchman left atrial appendage closure (LAAC) device (Boston Scientific Corporation) for stroke prevention in patients with nonvalvular atrial registries were published by David R. Holmes Jr, MD, et al in Journal of the American College of Cardiology (JACC; 2019;74:2878–2889). The investigators sought to evaluate 4.5- to 5-year data in two FDA-mandated registries for safety and efficacy of LAAC with the Watchman device: CAP (Continued Access to PROTECT-AF) and CAP2 (Continued Access to PREVAIL).
According to the investigators, these two registries provide the largest source of follow-up data from patients implanted with an LAAC device. Both registries accompanied their respective randomized clinical trials, PROTECT-AF and PREVAIL. The trials used the same endpoints (primary efficacy of composite of stroke, systemic embolism, cardiovascular/unexplained death, and safety).
As summarized in JACC:
- CAP was composed of 566 patients with an average follow-up of 50.1 months (2,293 patient-years).
- CAP2 included 578 patients with an average follow-up of 50.3 months (2,227 patient-years).
- CAP2 patients were significantly older and had higher CHA2DS2-VASc scores (4.51 vs. 3.88; P < .001). CHA2DS2-VASc includes congestive heart failure, hypertension, age ≥ 75 years, diabetes mellitus, stroke/transient ischemic attack, vascular disease, age 65–74 years, sex category.
- Procedural success was similar in both registries (94%).
The investigators found that the primary composite endpoint occurred at a rate of 3.05 per 100 patient-years in CAP and 4.80 per 100 patient-years in CAP2. Events contributing to this endpoint were most commonly cardiovascular/unexplained death (1.69 per 100 patient-years for CAP; 2.92 per 100 patient-years for CAP2).
Additionally, they reported that hemorrhagic stroke occurred significantly less frequently than ischemic stroke (0.17 per 100 patient-years in CAP; 0.09 per 100 patient-years in CAP2), and total stroke rates were significantly less than predicted by CHA2DS2-VASc score (78% reduction with CAP; 69% reduction with CAP2).
In JACC, the investigators concluded that these registries, which contain the longest and largest follow-up data from patients with the Watchman device, support LAAC as a safe and effective therapy for long-term anticoagulation in those with nonvalvular atrial fibrillation and document the lowest rate of hemorrhagic stroke identified in this population.