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 P2Y ₁₂ -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. P2Y ₁₂ 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 (ΔPRU −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 .

Clinical Perspective

• What Is New? This three-arm randomized pilot trial is the first to demonstrate that aspirin-free half-dose ticagrelor monotherapy (45 mg twice daily) initiated on the day of percutaneous coronary intervention — without any dual antiplatelet run-in period — produces platelet inhibition approximately three-fold greater than standard aspirin-plus-clopidogrel therapy in East-Asian patients with chronic coronary syndrome, with an identical pharmacodynamic effect whether aspirin is retained or omitted.

• What Are the Clinical Implications? For East-Asian patients with chronic coronary syndrome undergoing elective percutaneous coronary intervention, a simplified aspirin-free half-dose ticagrelor monotherapy strategy initiated at the index procedure achieves superior platelet inhibition with a favorable 12-month safety profile — no stent thrombosis, no cardiac death, and only one non-major gastrointestinal bleed — supporting the feasibility of a definitive adequately powered randomized trial to validate this approach and potentially reduce bleeding risk without compromising ischemic protection in this East-Asian population.