Ticagrelor monotherapy versus dual antiplatelet therapy after primary percutaneous coronary intervention: one-year outcomes of the pilot STOP-IMH randomised trial.

BACKGROUND: Ticagrelor monotherapy after a short period of dual antiplatelet therapy (DAPT) has shown to be safe and effective after percutaneous coronary intervention (PCI), including primary PCI in ST-elevation myocardial infarction (STEMI). However, direct omission of aspirin could further reduce bleeding risk. AIMS: We aimed to assess the impact of ticagrelor monotherapy directly after primary PCI regarding ischemic events, and to investigate the effect on clinical bleeding events. METHODS: In this multicentre open-label pilot study, 200 STEMI patients were 1:1 randomised to ticagrelor monotherapy versus ticagrelor plus aspirin, directly after primary PCI. Major adverse cardiac and cerebral events (MACCE) and bleeding were assessed at 13 months. Incidence of intramyocardial haemorrhage (IMH) was compared. RESULTS: In the ticagrelor monotherapy group (n=98) and DAPT group (n=101), MACCE occurred in 4.1% versus 4.0% (HR:1.04, 95%CI: 0.26-4.17). Clinically relevant bleeding was observed in 4.1% versus 10.9% (HR: 0.37, 95%CI: 0.12-1.17), and clinically relevant non-access site bleeding in 2.0% versus 9.9% (HR:0.20, 95%CI: 0.04-0.92). CONCLUSIONS: While no significant difference in ischemic events was observed between ticagrelor monotherapy and DAPT in the first thirteen months after primary PCI, this pilot study is underpowered to confirm efficacy. In addition, non-access site bleeding events were significantly reduced and all clinical bleeding events tended to be reduced. Incidence of IMH was similar between groups.