Diagnostic and prognostic performance of the ratio between high-sensitivity cardiac troponin I and troponin T in patients with chest pain.

Background: Elevations of high-sensitivity cardiac troponin (hs-cTn) concentrations not related to type 1 myocardial infarction are common in chest pain patients presenting to emergency departments. The discrimination of these patients from those with type 1 myocardial infarction (MI) is challenging and resource-consuming. We aimed to investigate whether the hs-cTn I/T ratio might provide diagnostic and prognostic increment in this context.
Methods: We calculated the hs-cTn I/T ratio in 888 chest pain patients having hs-cTnI (Abbott Laboratories) or hs-cTnT (Roche Diagnostics) concentrations above the respective 99th percentile at 2 hours from presentation. All patients were followed for one year regarding mortality.
Results: The median hs-cTn I/T ratio was 3.45 (25th, 75th percentiles 1.80-6.59) in type 1 MI patients (n = 408 ☯46.0%]), 1.18 (0.81-1.90) in type 2 MI patients (n = 56 ☯6.3%]) and 0.67 (0.39-1.12) in patients without MI. The hs-cTn I/T ratio provided good discrimination of type 1 MI from no type 1 MI (area under the receiver-operator characteristic curve 0.89 ☯95% confidence interval 0.86-0.91]), of type 1 MI from type 2 MI (area under the curve 0.81 ☯95% confidence interval 0.74-0.87]), and was associated with type 1 MI in adjusted analyses. The hs-cTn I/T ratio provided no consistent prognostic value.
Conclusions: The hs-cTn I/T ratio appears to be useful for early diagnosis of type 1 MI and its discrimination from type 2 MI in chest pain patients presenting with elevated hs-cTn. Differences in hs-cTn I/T ratio values may reflect variations in hs-cTn release mechanisms in response to different types of myocardial injury.
Competing Interests: Dr Eggers has consulted for Roche Diagnostics. Professor Cullen has consulted for Abbott Diagnostics, Siemens Healthineers and Beckman Coulter. Dr Parsonage has consulted for Abbott Diagnostics and Siemens Healthineers. Professor Cullens and Dr Parsonages institution has received research funding from Abbott Diagnostics, Siemens Healthineers and Beckman Coulter. Professor Pickering has consulted for Abbott Diagnostics. Professor Richards has consulted for and/or received grants/in-kind support from Roche Diagnostics, Abbott Laboratories and Thermo Fisher. Dr Than has consulted for Abbott Diagnostics, Radiometer, Roche Diagnostics, Siemens Healthineers and received funding from Abbott Diagnostics, Beckman Coulter and Roche Diagnostics. The authors have declared that no competing interests exist.