The Prognostic Significance of Elevated Cardiac Troponin in Non-Cardiac Medical Disorders. Pilot Study

Background: Several studies have linked elevated cardiac troponin to increased overall risk in patients with acute coronary syndrome but the prognostic significance of elevated troponin in non-cardiac conditions remains scanty. Objectives: The primary aim of this study was to investigate the prognostic significance of elevated high sensitivity troponin T (TnT-HS) in non-cardiac disorders outside the remit of an acute coronary syndrome (ACS). Secondarily we aimed to investigate the impact of cardiovascular comorbidities and other clinical presentations in the release of cardiac biomarkers in non-cardiac disorders. Methodology: This was a retrospective electronic patient record pilot review where all patients with elevated TnT-HS without acute coronary syndrome, recent angioplasty or heart failure within a three month period were enrolled into the study and subsequently followed prospectively for a six month period. From January 1, 2016 to June 30, 2016, a total of 2535 patients were screened of which 306 patients had elevated TnT-HS and 162 patients met the study inclusion criteria. Data were encrypted and collected in Google database format, exported into excel spreadsheet, analyzed and computed using SPSS (version 24) to identify clinical associations with increased values of TnT-HS. Results: Most troponin TnT-HS samples (77.1%) were obtained from emergency room (ER) attendance and 63.4% of patients were male. The mean age was 72 years and no correlation were found between age and troponin levels (rs = -0.18, p = 0.816) by Spearman Rank-order correlation. Although expectedly patients with diagnosis of acute coronary syndrome displayed TnT-HS values significantly higher than those of other groups, positivity to TnT-HS (> 40 ng/l) was also observed in patients with other clinical conditions. In multivariate analysis, baseline chronic kidney disease (CKD), acute infectious diseases mainly urinary tract infection and cerebrovascular events (CVA) were independently associated with TnT-HS positivity at admission. Observations from the cohort as a whole; TnT-HS positivity exhibited high sensitivity and negative predictive value, counterbalanced by low specificity and limited positive predictive value. Major adverse cardiac and cerebral events (MACCE) were significant within 6 months including; Death (13.7%), MI (3.9%), Stroke (ischemic 4.6%, hemorrhagic 2.3%, TIA 0.8%) p value < 0.02. Conclusions: TnT-HS positivity should be cautiously interpreted in patients exhibiting non acute cardiac conditions associated CKD, infections, and CVAs. This troponin elevation in non-cardiac conditions still carries a significant adverse prognosis. After adjusting for age and renal insufficiency, we can suggest a new cut off level of TnT-HS > 30 ng/l to have increased risk of MACCE within 180 days in non-cardiac conditions.