The temporal trends of ST-elevation myocardial infarction mortality according to infarct size and location: insights from the UK National MINAP registry from 2005 to 2019

Background and aims Myocardial infarction size is associated with mortality in ST-elevation myocardial infarction (STEMI). With advances in primary percutaneous coronary intervention (PPCI) and medical therapy, whether this relationship has changed over time is unclear. Methods Patients with STEMI in England and Wales from 2005-2019 were included from the national AMI MINAP registry, with mortality linkage to 2021. Primary outcomes were all-cause mortality at 30-days and 1-year according to infarct size, using Cox regression models. Infarct size was stratified by Tertiles (T1-3) of peak troponin level (T1: smallest, T3: largest), across the early (2005-2009), middle (2010-2014) and late (2015-2019) periods. Subgroup analyses assessed relationship according to infarct-location (anterior versus non-anterior). Results 177,214 STEMI patients were included. Adjusted 30-day mortality risk according to infarct size was highest in the early period (aHR: 1.32, 1.21-1.45, P<0.001), compared to middle (1.12, 1.04-1.20, P=0.002) and late study periods (1.05, 0.96-1.14, P=0.299). The relationship between infarct size and 30-day mortality was significant for patients with anterior STEMI in early (1.39, 1.22-1.57, P<0.001) but not middle or late periods, while remained significant for non-anterior infarction until the late period (early: 1.28, 1.13-1.45, P<0.001; middle: 1.17, 1.06-1.29, P=0.002; late: 1.09, 0.96-1.24, P=0.180). Conclusions We observed an independent relationship between infarct size and STEMI mortality, strongest between 2005-2009, which reduced over time, becoming non-significant in the 2015-2019 period. This association diminished more rapidly for patients with anterior STEMIs. These findings underscore the potential role of contemporary revascularization, systems of care and guideline-directed medical therapy in reducing STEMI-related mortality.