Minor troponin T elevation in patients 6 months after acute myocardial infarction: an observational study

Troponin elevation in patients with stable coronary heart disease is associated with adverse outcome and prognosis. However, the mechanism is not yet clearly understood. Our objectives were to examine the prevalence and range of cardiac troponin T (cTnT) in stable patients, 6 months after acute myocardial infarction (AMI) using a new high sensitive cTnT assay and to investigate the association of minor cTnT elevation in these patients to clinical variables, NT-proBNP and cardiac MRI-findings. cTnT was measured in 98 patients 6 months after AMI with a precommercial assay by electrochemiluminescence methods (Roche Diagnostics, Mannheim, Germany). cTnT values were correlated with clinical and angiographic variables, NT-proBNP concentrations and with cardiac MRI-findings. Minor cTnT concentrations were detectable in 90% of the entire cohort, of whom 16% had cTnT values above the 99th percentile (> 12 ng/L). These patients were also significantly older, suffered more frequently from hypertension, had a higher New York Heart Association class and received more often diuretics at follow up. Patients with cTnT elevation had a more impaired left ventricular ejection fraction (P = 0.02) but did not have an increased infarct size (P = 0.73). Elevated minor cTnT levels are frequently detectable in patients 6 months after AMI. Increased cTnT level were associated with clinical parameter for heart failure, impaired ejection fraction and higher NT-proBNP levels suggesting that myocardial dysfunction is a main cause for cTnT elevation in these patient group.