Boston Scientific said two post-implant drug regimens met SIMPLAAFY’s six-month noninferiority test against dual antiplatelet therapy, adding trial evidence on medication choices after WATCHMAN FLX Pro placement.
The study enrolled 1,857 patients at 86 U.S. sites, according to Boston Scientific. ClinicalTrials.gov describes three groups: daily aspirin; a reduced-dose non-vitamin K antagonist oral anticoagulant (NOAC) for three months followed by aspirin; and aspirin with clopidogrel for six months, then aspirin.
The primary composite, assessed six months after randomization, included death from any cause, all stroke, systemic embolism and major bleeding under International Society on Thrombosis and Haemostasis criteria. Boston Scientific said both single-drug approaches met the trial’s standard for noninferiority to DAPT. The company also reported less bleeding and similar ischemic-stroke rates with those regimens.
Boston Scientific gave a 0.7% ischemic-stroke rate for the DAPT group, but did not provide corresponding rates for the other groups or arm-specific bleeding and composite results. It separately reported that 45-day imaging found device-related thrombus in 0.9% of patients in the reduced-dose NOAC group, compared with 3.4% in the DAPT group (P=0.01).
After left atrial appendage closure, medication is used to address clot risk while the device heals; antithrombotic treatment also carries bleeding risk, Boston Scientific says. The company lists short-term oral anticoagulation with aspirin followed by antiplatelet treatment, or DAPT, among post-implant options. SIMPLAAFY tests medication schedules after implantation, not the device against drug treatment.
The results were presented Nov. 2 at Transcatheter Cardiovascular Therapeutics 2026. ClinicalTrials.gov lists follow-up through 12 months.
