Rationale and design of non-antithrombotic therapy after transcatheter aortic valve implantation (NAPT) trial

Background: Despite the wide implementation of transcatheter aortic valve implantation (TAVI), the optimal antithrombotic therapy after TAVI has not been established yet. Owing to the accumulating evidence supporting the efficacy and safety of single antiplatelet therapy (SAPT) over dual antiplatelet therapy, the latest guideline recommends life-long SAPT. However, there is scarce evidence supporting SAPT compared with non-antithrombotic therapy. Given the vulnerability of patients undergoing TAVI in terms of high bleeding risk, the benefit of SAPT may be canceled out by its potential increased bleeding risk. Study design and objectives: Non-antithrombotic Therapy After Transcatheter Aortic Valve Implantation (NAPT) Trial is a prospective, randomized controlled, open-label blinded endpoint multicenter trial conducted in Japan, testing the non-inferiority of non-antithrombotic therapy compared with aspirin monotherapy in patients who underwent TAVI and had no indications for long-term oral anticoagulation therapy (OAC). Patients who successfully underwent trans-femoral TAVI for severe aortic stenosis with either balloon-expandable or self-expandable valves are eligible for inclusion. Key exclusion criteria are (i) occurrence of perioperative complications (ii) indications of taking antithrombotic drugs for other reasons; (iii) eGFR <30 ml/min/1.73 m2 or hemodialysis or peritoneal dialysis. A total of 360 patients will be randomized (1:1) to aspirin monotherapy vs. non-antithrombotic therapy. The primary outcome is a composite of all-cause mortality, myocardial infarction, stroke, and bleeding. All bleeding events based on the Valve Academic Research Consortium 3 are included as a component of the primary outcome. Conclusion: The NAPT trial will determine the non-inferiority of a non-antithrombotic therapy compared with aspirin monotherapy after TAVI.