Half-Dose Ticagrelor Monotherapy Versus Standard Dual Antiplatelet Therapy in Chronic Coronary Syndrome After Percutaneous Coronary Intervention: A Randomized Pilot Trial With PRU-Guided Pharmacodynamic Assessment

Background: Aspirin-free P2Y12-inhibitor monotherapy after percutaneous coronary intervention (PCI) is an alternative to dual antiplatelet therapy (DAPT), but the evidence rests largely on full-dose ticagrelor in acute coronary syndrome and on designs retaining a DAPT run-in; East-Asian patients may not require the same antithrombotic intensity. We compared standard DAPT, DAPT with half-dose ticagrelor, and aspirin-free half-dose ticagrelor monotherapy initiated on the day of PCI in chronic coronary syndrome (CCS). Methods: Sixty-one East-Asian patients with CCS scheduled for elective PCI were randomized 1:1:1 to Control (aspirin plus clopidogrel), Experimental A (aspirin plus ticagrelor 45 mg twice daily), or Experimental B (ticagrelor 45 mg monotherapy, aspirin discontinued at day 2). DAPT arms continued for six months; Experimental B continued indefinitely. P2Y12 reaction units (PRU) were measured at baseline and at a median of 17 days. Results: PRU reduction was three-fold greater in both ticagrelor arms than in Control ({Delta}PRU -188 and -181 versus -60.5; P<0.001), with no difference between ticagrelor arms (P=0.772). At 12 months, major adverse cardiovascular events (MACE) and clinically relevant bleeding each occurred in 1 of 17 Experimental B patients (5.9%) and in neither other arm. One Experimental A patient crossed over for ticagrelor-induced dyspnea; no stent thrombosis or cardiac death occurred. Conclusions: In East-Asian patients with CCS, half-dose ticagrelor produced markedly greater platelet inhibition than standard DAPT, with an identical effect whether given with or without aspirin. It merits evaluation in an adequately powered randomized trial. Clinical Trial Registration. URL: https://www.clinicaltrials.gov; Unique Identifier: NCT07622056