Prevalence of elevated cardiac troponin in five non-cardiac diseases

Abstract Background Cardiac troponins (cTns) are regulatory proteins located in the cardiac muscle cells (cardiomyocytes). Since the 1990s, cTns have been the biochemical gold standard for detecting myocardial infarction. CTns are well studied among patients with cardiac illnesses and elevated concentrations are known to reflect myocardial injury. Still, high cTn concentrations are found in several non – cardiac conditions where signs of cardiac dysfunction are absent(1). This is especially found to be true for cardiac troponin T (cTnT) which is, more frequently than cardiac troponin I (cTnI), found to be elevated in patients with non – cardiac conditions(2,3). A study from 2016 of 1012 patients admitted to the emergency room, found troponin T elevations in 40.8% of patients without acute coronary syndrome vs. 7.4% with cTnI elevations(3). To our knowledge, no previous study has investigated cTn elevations across disease -groups where elevations of cTns are frequently detected. Purpose We aimed to investigate the prevalence of cTnT in five clinical non-cardiac disease-groups where frequent elevation of cTnT is previous described; Sepsis, rhabdomyolysis, end-stage renal disease (ESRD), stroke, and major non-cardiac surgery (MNCS). Methods Our study was a single-center prospective cross-sectional cohort study. Over a 6-month period, we included patients in the five above mentioned disease-groups. We excluded patients with any symptoms of cardiac disease or a prior history of cardiac diseases. All patients were included within 48 hours of admission and underwent clinical examination, vital signs, 12-lead electrocardiogram, echocardiography, and collections of blood samples. Cardiac troponin T was measured at patient’s bedside upon inclusion with the Cobas h232, cTnT point-of-care test. Results 89 patients were eligible for inclusion, 15 with sepsis, 18 with rhabdomyolysis, 11 with end-stage renal disease, 22 with stroke and 23 with major non-cardiac surgery. 53% were men. 17 patients (19%) had signs of cardiac disease confirmed on echocardiographic and/or electrocardiographic examinations and were excluded. Out of the 72 patients without signs of cardiac disease, elevated cTnT above the 99th percentile was found in 21 (29%) patients; 4 (36%) with sepsis, 6 (60%) with rhabdomyolysis, 4 (44%) with ESRD, 2 (9.5%) with stroke and 5 (24%) with MNCS. The median of cTnT in patients with elevated cTnT across all patient groups was 79.5 ng/L (IQR 52.5ng/L – 187.8 ng/L). Conclusions Cardiac troponin T elevations are frequent in the five non-cardiac diseases investigated. Elevations are most frequent in patients with rhabdomyolysis and end-stage renal disease. Further investigation is warranted to elucidate the underlying etiology contributing to the elevation of cardiac troponin in non-cardiac diseases.