Long-term clinical outcomes in patients with non-ST-segment Elevation Acute Coronary Syndrome and ST-segment elevation myocardial infarction with thrombolysis in myocardial infarction 0 flow.

Background: Thrombolysis in Myocardial Infarction (TIMI) 0 flow often characterizes ST-segment Elevation Myocardial Infarction (STEMI) patients, but may also feature in non-ST-segment Elevation Acute Coronary Syndrome (NSTE-ACS). Since recanalization usually occurs later in NSTE-ACS patients, the aim of this study was to assess whether patients presenting with NSTE-ACS and TIMI 0 flow have worse clinical outcomes as compared to patients presenting with STEMI and TIMI 0 flow. Methods: A single-center retrospective cohort study was conducted with patients treated for NSTE-ACS and STEMI with TIMI 0 flow at diagnostic angiogram between January 2015 and December 2019. The two patient groups were 1:1 matched using a propensity score logistic regression model. The primary outcome was Major Adverse Cardiac Events (MACE), a composite of all-cause mortality, any myocardial infarction, coronary artery bypass graft, urgent target vessel revascularization or stroke during long term follow-up. Results: The total population consisted of 1255 ACS patients, of which 249 NSTE-ACS and 1006 STEMI patients. After propensity score matching, 234 NSTE-ACS patients were matched with 234 STEMI patients. In this matched population, the mean age was 62.6 (±12.4) years and 75.2 % of the patients was male. The median follow-up time was 3.2 years. MACE rates during follow-up were similar between the two matched groups (HR = 0.84 [95 % CI 0.60 - 1.12] with p = 0.33) with cumulative event-free survival of 63.3 % in the NSTE-ACS group vs 59.3 % in the STEMI group at 6 year follow-up. Conclusion: In this retrospective study, a culprit lesion with TIMI 0 flow has similar clinical outcome in NSTE-ACS and STEMI patients. Further research is warranted to determine optimal the timing of PCI in NSTE-ACS patients with TIMI 0 flow.