Percutaneous left atrial appendage closure for stroke prevention in patients with atrial fibrillation: an assessment of net clinical benefit

Aims The PROTECT-AF (WATCHMAN Left Atrial Appendage System for Embolic Protection in Patients with Atrial Fibrillation) trial found left atrial appendage (LAA) closure an alternative to anticoagulation in selected patients with non-valvular atrial fibrillation (AF). We aim to estimate the net clinical benefit (NCB) of percutaneous LAA closure. Methods and results Post hoc analysis of outcomes among 707 adults with AF in the PROTECT-AF trial and 566 in the Continued Access (CAP) registry undergoing LAA closure with the Watchman device compared with sustained anticoagulation. Outcomes were ischaemic stroke, intracranial haemorrhage, major bleeding, pericardial effusion, and death, weighted to reflect the relative impact in terms of death and disability. Net clinical benefit was calculated as the sum of annualized rates of these outcomes after intervention minus rates on warfarin. The NCB of LAA closure during 1623 person-years follow-up in the trial was 1.73/year (95 CI: -0.54 to 4.39/year) and during 741 patient-years in the registry was 4.97/year (95 CI: 3.07-7.15/year). Among patients with a history of ischaemic stroke, the NCB was greater in the registry (8.68/year, CI: 2.82-14.92/year) than the trial (4.30/year, CI -2.07 to 11.25/year). In the registry, the NCB of LAA closure increased from 2.22/year (CI: 0.27-6.01/year) in patients with CHADS(2) scores = 1 to 6.12/year (CI: 3.19-8.92/year) in those with scores >= 2. Conclusion Combining rates of thrombo-embolism, intracranial haemorrhage, major adverse events, and death allows objective comparison of the benefit and risk of device therapy vs. anticoagulation in patients with AF. The NCB of LAA closure is greatest for patients at a higher risk of stroke.