Mortality related to left ventricular ejection fraction and obstructive coronary artery disease in non-ST-segment elevation myocardial infarction

Abstract Background Extent of coronary artery disease (CAD) and the severity of reduced left ventricular ejection fraction (LVEF) have both been associated with the prognosis after non-ST-segment elevation myocardial infarction (NSTEMI). However, the contemporary mortality associated with the extent of obstructive CAD over a range of LVEF remains uncertain. Purpose The aim of this study was to assess the impact of CAD and LVEF on all-cause death following a first-time NSTEMI. Methods We included consecutive first-time NSTEMI patients undergoing coronary angiography from 2010 to 2021 in Western Denmark. Patients were stratified by extent of obstructive vessel disease (VD; 1, 2, or 3VD) and LVEF (≥51%, 41-50%, or 10-40%). Patients with previous myocardial infarction, percutaneous coronary intervention, or coronary artery bypass grafting were excluded. The primary outcome was all-cause death. We calculated 5-year cumulative incidence proportions (CIP) as a measure of absolute risk and adjusted hazard ratios (HR). Results A total of 8,770 patients with first-time NSTEMI and obstructive CAD were examined with coronary angiography. Two-thirds were male and median age was 68 years (Q1-Q3: 58-78). The increase in mortality associated with decreasing LVEF was greater than observed by extent of CAD (Table). Thus, the 5-year mortality increased stepwise by extent of CAD from 14% for 1VD to 31% for 3VD (adjusted HR 1.35, 95% CI:1.19-1.54), but from 12% for LVEF ≥51% to 40% for LVEF 10-40% (adjusted HR 2.32, 95% CI: 2.04-2.65). When combining LVEF and extent of CAD, an increase in 5-year mortality was found from 9% for 1VD and LVEF ≥51% to 46% for 3VD and LVEF 10-40% (risk difference of 37.1%; Figure). Correspondingly, using 1VD and LVEF ≥51% as reference, the adjusted HRs increased gradually with extent of CAD and decline in LVEF to 3.05 (95% CI: 2.51-3.70) for patients with 3VD and LVEF 10-40% (Table). Conclusion In a contemporary all-comers cohort of first-time NSTEMI patients, increasing extent of CAD and declining LVEF are both associated with a gradual increase in 5-year mortality. Our data suggest that the level of LVEF reduction was more strongly associated with 5-year mortality than CAD extent.