Prognosis in relation to high-sensitivity cardiac troponin T levels in patients with myocardial infarction and non-obstructive coronary arteries

BACKGROUND: Myocardial infarction (MI) with non-obstructive coronary arteries (MINOCA) is a recently recognized condition where biomarkers and prognosis are less well studied than in MI with obstructive coronary artery disease (MI-CAD). We therefore aimed to investigate the one-year prognostic value of high-sensitivity cardiac troponin T (hs-cTnT) levels in MINOCA in comparison to MI-CAD. METHODS: In this registry-based cohort study, we used data from patients with a discharge diagnosis of MI, admitted between 2009 and 2013 to Swedish hospitals using the hs-cTnT assay. Only patients without previously known coronary artery disease were considered. Patients with and without coronary stenosis >50% were regarded to have MI-CAD and MINOCA, respectively. Assessed outcomes included all-cause mortality, cardiovascular (CV) mortality and major CV events (MACE), defined as the composite of CV death or admissions for non-fatal MI, heart failure (HF) or ischemic stroke. RESULTS: The study cohort consisted of 1639 MINOCA and 17,304 MI-CAD patients. In adjusted analyses, hs-cTnT (ln) in MINOCA patients predicted all-cause mortality (HR 1.32 95% CI 1.11-1.56), CV mortality (HR 2.11 95% CI 1.51-2.96) and MACE (HR 1.44 95% CI 1.20-1.72). Hs-cTnT (ln) also predicted readmissions for HF (HR 1.51 95% CI 1.51-2.96) but not non-fatal MI or stroke. Interaction analyses suggested that hs-cTnT (ln) was at least as prognostic in patients with MINOCA compared to MI-CAD. CONCLUSIONS: Hs-cTnT levels in MINOCA patients are strong and independent predictors of adverse outcome. Consideration of hs-cTnT levels is important for risk assessment of MINOCA patients.