Ticagrelor versus clopidogrel in patients with STEMI treated with thrombolysis: the MIRTOS trial

Aims: We aimed to demonstrate whether coronary microvascular function is improved after ticagrelor administration compared to clopidogrel administration in STEMI subjects undergoing thrombolysis. Methods and results: MIRTOS is a multicentre study of ticagrelor versus clopidogrel in STEMI subjects treated with fibrinolysis. We enrolled 335 patients <75 years old with STEMI eligible for thrombolysis, of whom 167 were randomised to receive clopidogrel and 168 to receive ticagrelor together with thrombolysis. Primary outcome was the difference in post-PCI corrected TIMI frame count (CTFC). All clinical events were recorded in a three-month follow-up period. From the 335 patients who were randomised, 259 underwent PCI (129 clopidogrel and 130 ticagrelor) and 154 angiographies were analysable for the study primary endpoint. No significant difference was found between the clopidogrel (n=85) and ticagrelor (n=69) groups for CTFC (24.33 +/- 17.35 vs 28.33 +/- 17.59, p=0.10). No significant differences were observed in MACE and major bleeding events between randomisation groups (OR 2.0, 95% CI: 0.18-22.2, p=0.99). Conclusions: Thrombolysis with ticagrelor in patients <75 years old was not able to demonstrate superiority compared to clopidogrel in terms of microvascular injury, while there was no difference between the two groups in MACE and major bleeding events.