Diagnosis of acute myocardial infarction in patients with renal insufficiency using high-sensitivity troponin T.

BACKGROUND: The objective of this study was to examine the diagnostic accuracy of high-sensitivity cardiac troponin T (hs-cTnT) for acute myocardial infarction (AMI) in patients with renal insufficiency, since this population has a high incidence of non-AMI elevations of hs-cTnT.

METHODS: In this prospective study, we enrolled 2249 consecutive patients presenting with chest pain in the emergency department (ED), of whom 19.5% had an estimated glomerular filtration rate (eGFR)cys of <60 mL·min-1 (1.73 m2)-1. Hs-cTnT levels were measured blindly at presentation.

RESULTS: Of the patients, 1108 (49.3%) were diagnosed as having AMI [321 with non-ST segment elevation myocardial infarction (NSTEMI)]. In patients whose final diagnosis was not AMI, there was a low but significant correlation between hs-cTnT and renal function [eGFRcys, r=-0.43 (-0.48, -0.38), p<0.001; eGFRcreat, r=-0.33 (-0.38, -0.27), p<0.001]. The area under the curve of the receiver operating characteristic (AUC) for hs-cTnT to diagnose AMI was 0.93 in patients with eGFRcys levels of <30 mL·min-1 (1.73 m2)-1, and AUCs did not vary significantly according to eGFR categories. On the basis of the ROC curve, the optimal threshold value for hs-cTnT was 143.6 ng·L-1 to diagnose AMI in patients with eGFRcys of <30 mL·min-1 (1.73 m2)-1, with a sensitivity of 83% and a specificity of 91%; 54.1 ng·L-1 in patients with eGFRcys between 30 and 59 mL·min-1, with a sensitivity of 90% and a specificity of 87%; 30.0 ng·L-1 in patients with eGFRcys between 60 and 89 mL·min-1, with a sensitivity of 89% and a specificity of 85%; and 20.3 ng·L-1 in patients with eGFRcys ≥90 mL·min-1 (1.73 m2)-1, with a sensitivity of 92% and a specificity of 88%. The same observations were done for the diagnosis of NSTEMI.

CONCLUSIONS: Using a higher hs-cTnT cut-off value based on eGFR level is necessary for accurate diagnosis of AMI or NSTEMI in patients with renal insufficiency.