Abstract 4287: Efficacy of Left Atrial Appendage Occlusion Device (WATCHMAN) in Prevention of Stroke: Subgroup Analysis of Protect AF Registry
The PROTECT AF trial was a prospective, randomized trial that included 800 patients and was designed to determine the efficacy of a Left Atrial Appendage (LAA) Occlusion Device (WATCHMAN) compared to long-term warfarin therapy for the prevention of embolic stroke (CVA) in patients with atrial fibrillation (AF). The primary endpoint was first occurrence of stroke, systemic embolism, or cardiovascular death. Analyses were performed on an intent-to-treat basis. Results showed a 39% decrease in all-cause mortality in the WATCHMAN arm compared to warfarin therapy. There were 32% fewer adverse events (CVA, embolization, cardiovascular or unexplained death) in the WATCHMAN arm; this specifically included 26% fewer strokes. We assessed the hypothesis that LAA occlusion was non-inferior relative to warfarin therapy in the prevention of the adverse events during subgroup analysis. To further elucidate the consistency of LAA occlusion, subgroup analysis was carried out after patients were grouped according to median age, CHADS2 score, and AF pattern at the time of enrollment. Results of subgroup analysis showed the device to control risk was consistent across all patient subgroups. Older patients or those with CHADS2 scores >1 had higher event rates for both treatment and control groups. The device to control hazard ratio was smallest for those with persistent AF (HR 0.19, 95% CI=0.04 – 0.98); this was due to both low rates for the device patients and high rates for the control patients. In conclusion, subgroup analysis confirms the non-inferiority of the WATCHMAN device compared to warfarin therapy in prevention of CVA, systemic embolization, or death.