Background and aim: This study aimed to investigate the efficacy and safety of dual and triple antiplatelet therapy (DAPT and TAPT) in patients with diabetes and acute ST segment elevation myocardial infarction (D-STEMI), who had undergone primary percutaneous coronary intervention (PCI).

Methods: We designed a phase IV, single-centre, randomised, double-blind, placebo-controlled study. The D-STEMI patients (n = 258) were randomly divided into three groups. Control group A (85 patients), was treated with aspirin and clopidogrel; group B (87 patients) received aspirin, clopidogrel, and tirofiban; and group C (86 patients) were treated with aspirin, ticagrelor, and tirofiban. Patients in all three groups received oral DAPT, and patients in groups B and C received intravenous tirofiban when primary PCI was performed.

Results: Compared to the findings in group A, the post-PCI Thrombolysis in Myocardial Infarction (TIMI) grade 3 blood flow in groups B and C increased significantly (TIMI grade 3 in groups A, B, C: 74%, 91%, and 98%, respectively; TIMI myocardial perfusion grade [TMPG] grade 3 in groups A, B, C: 59%, 86%, and 97%, respectively), and the incidence of major adverse cardiac events (MACE) decreased significantly (p < 0.05). Compared to the findings in group B, the rate of TMPG 3 in group C was significantly higher (p < 0.05) and the incidence of MACE was significantly lower (p < 0.05). Patients in group B exhibited minor bleeding; however, the incidence of mild to moderate bleeding in group C increased significantly (p < 0.05).

Conclusions: TAPT effectively improved the TIMI blood flow and TMPG and reduced the occurrence of MACE. Ticagrelor was more effective than clopidogrel in TAPT; however, when using the combination of aspirin, ticagrelor, and tirofiban, close monitoring is required for possible bleeding complications.