Relation of Chronic Myocardial Injury and Non-ST-Segment Elevation Myocardial Infarction to Mortality

Abstract

The prognosis in patients with chest pain and chronic myocardial injury compared with patients with non-ST-segment elevation myocardial infarction (NSTEMI) is unknown. This study aims to investigate differences in long-term outcomes. Patients with chest pain at Karolinska University Hospital, Sweden from 2011 to 2014, who had stable high-sensitivity cardiac troponin T (hs-cTnT) levels were compared with patients with NSTEMI. We estimated hazard ratios with 95% confidence intervals for the risk of all-cause mortality, myocardial infarction, and heart failure at different hs-cTnT levels using patients with NSTEMI as referent. A total of 20,387 patients were included, of whom 927 had NSTEMI. Among 19,460 patients with stable hs-cTnT levels, 1,528 had chronic myocardial injury defined as stable hs-cTnT levels > 14 ng/L. Mean follow-up was 3.2 years. Patients with hs-cTnT levels of <5 and 5 to 9 ng/L had a lower risk, while patients with chronic myocardial injury with hs-cTnT levels of 30 to 49 and ≥50 ng/L had a higher risk of death (adjusted hazard ratios, 95% confidence intervals: 1.65, 1.30 to 2.10 and 2.13, 1.60 to 2.84, respectively) compared with patients with NSTEMI. Patients with hs-cTnT levels <15 ng/L had a lower risk of heart failure, with no difference in risk at higher hs-cTnT levels. All stable hs-cTnT levels were associated with a lower risk of myocardial infarction (MI). In conclusion, patients with chest pain and stable hs-cTnT levels 10 to 29 ng/L have a similar risk, and those with chronic myocardial injury with hs-cTnT levels of ≥30 ng/L have an increased risk of long-term all-cause mortality compared with patients with NSTEMI.