After percutaneous coronary intervention (PCI), antiplatelet treatment nonadherence is typical, even in clinical studies. For a study, researchers sought to determine how non-compliance with the study protocol regimens affected the MASTER DAPT (Management of High Bleeding Risk Patients Post Bioresorbable Polymer Coated Stent Implantation With an Abbreviated Versus Prolonged DAPT Regimen) trial results.

At 1 month following PCI, 4,579 patients with high bleeding risks were randomized to receive either single antiplatelet therapy (SAPT) for 11 months (or 5 months in patients on oral anticoagulation [OAC]) or dual antiplatelet therapy (DAPT) for ≥2 months, followed by SAPT. At 335 days, major or clinically significant nonmajor bleeding (MCB), net adverse clinical events (NACE), and major adverse cardiac and cerebral events (MACE) were all coprimary outcomes. In order to account for nonadherence to Academic Research Consortium type 2 or 3, inverse probability-of-censoring weights were applied.

In all, 214 (9.4%) patients in the standard treatment group and 464 (20.2%) patients in the abbreviated-treatment group experienced nonadherence of type 2 or 3. NACE (HR: 1.01; 95% CI: 0.88-1.27) and MACE (HR: 1.07; 95% CI: 0.83-1.40) did not differ at inverse probability-of-censoring weights analyses, and MCB was consistently lower with shortened versus standard treatment (HR: 0.51; 95% CI: 0.60-0.73) across OAC subgroups. Among OAC patients, SAPT discontinuation 6 months after PCI was associated with similar MACE and lower MCB (HR: 0.47; 95% CI: 0.22-0.99) compared with SAPT continuation.

In the MASTER DAPT adherent group, 1-month DAPT was related to equivalent NACE or MACE and reduced MCB when compared to ≥3-month DAPT. In OAC patients, SAPT continuation was related to higher MCB and comparable MACE as SAPT termination after 6 months.