The predictive value of high sensitivity-troponin velocity within the first 6 h of presentation for cardiac outcomes regardless of acute coronary syndrome diagnosis

Background Low-range troponin elevations without clear coronary manifestations remain a major diagnostic challenge. We sought to determine if troponin velocity could allow for early identification of patients without an obvious cardiac diagnosis and who are at increased risk for cardiac-specific events. Methods & results All patients presenting to South Australian public hospitals between 1 September 2011 and 30 September 2012, with at least two troponin measurements during the first 6 h after ED presentation were included. Diagnoses were classified as 'coronary', 'non-coronary cardiac', and 'non-cardiac' using the International Classification of Diseases 10 codes. The relationship between troponin velocity and cardiac-specific mortality and combined cardiac outcome (death and myocardial infarction) was assessed using Fine and Gray competing risk models in patients with an initial troponin < 52 ng/L. Sensitivity analyses were performed using different initial and maximum troponin cut-off values. In total, 7300 patients were identified. A troponin velocity of 2.5 ng/L/h or greater in the non-cardiac (n = 2793) patient group was significantly associated with an increased risk for 12-month cardiac mortality (sub-hazard ratio [SHR] 2.90, 95% CI 1.33-6.34) and combined cardiac outcome (SHR 2.08, 95% CI 1.01-4.27). This association was consistent for coronary (n = 3835) and non-coronary cardiac (n = 672) patient groups, and remained after sensitivity analyses. Conclusions The significant association observed across all patient groups suggests that troponin velocity could be used for early risk stratification of patients with low-range troponin elevations without clear cardiac symptoms. These results may help guide future clinical trials aimed at assessing the utility of cardiac-targeted interventions in this challenging patient population.