Diagnosis of Acute Myocardial Infarction in Hemodialysis Patients With High-Sensitivity Cardiac Troponin T Assay Hua-Lan Huang, MM; Shuai Zhu, MM; Wei-Qing Wang, MM; Xin Nie, MM; Ying-YingShi, MD; Yong He, MM; Hao-Lan Song, BM; Qiang Miao, BM; Ping Fu, MD; Lan-Lan Wang, MD; Gui-Xing Li, MM  Context.—Cardiac troponins have become the gold standard for diagnosing acute myocardial infarction (AMI) in the general population; however, their diagnostic accuracy for hemodialysis (HD) patients presenting with chest pain or dyspnea is uncertain. Objective.—To examine the diagnostic accuracy of high- sensitivity cardiac troponin T (hs-cTnT) assay for AMI in HD patients. Design.—In this prospective study, we enrolled 670 consecutive stable HD patients presenting with chest pain or dyspnea on routine predialysis therapy in the nephrol- ogy department. Receiver operating characteristic (ROC) curves were used to examine the diagnostic accuracy of hs- cTnT levels at enrollment in HD patients presenting with chest pain or dyspnea, and the dynamic change in these levels after 3 hours. Results.—Acute myocardial infarction was the adjudi- cated final diagnosis in 12% of HD patients. Among patients with a final diagnosis other than AMI, 97% had a plasma hs-cTnT concentration above the 99th percentile. At the time of enrollment, the area under the ROC curve of hs-cTnT levels for diagnosis of AMI was 0.68 (95% confidence interval [CI], 0.62–0.74; P , .001) with a cutoff value of 107.7 ng/L; the relative change after 3 hours was 0.90 (95% CI, 0.82–0.96, P , .001) with a cutoff value of 24%, and the absolute change was 0.88 (95% CI, 0.82–0.94, P , .001) with a cutoff value of 32.6 ng/L. The prognostic value for 40-day mortality varied with the magnitude of elevation in hs-cTnT levels. Conclusions.—Tracking the dynamic change in hs-cTnT levels during the short term significantly increased this measure’s diagnostic accuracy for AMI in HD patients. (Arch Pathol Lab Med. 2016;140:75–80; doi: 10.5858/ arpa.2014-0580-OA) T he most common cause of death among hemodialysis (HD) patients is cardiac death—predominantly acute myocardial infarction (AMI), which accounts for approxi- mately 50% of all deaths. 1 Rapid and accurate diagnosis of AMI is an urgent clinical need, as delays increase the risk of mortality. 2,3 Delayed exclusion of this diagnosis prolongs hospital length of stay, increases patients’ anxiety, and carries enormous costs for the health care system. 4 Cardiac troponins have become the gold standard for diagnosing AMI in the general population. 5,6 However, patients with end-stage renal disease (ESRD) have a high incidence of baseline elevation of troponins, 7–9 making the diagnosis of AMI in patients with ESRD more difficult. According to the clinical practice guidelines of the National Academy of Clinical Biochemistry, measurement of cardiac troponin T (cTnT) concentration is warranted for evaluating AMI in the population with renal failure for those who present with symptoms, electrocardiographic findings, or other clinical evidence suggestive of myocardial ischemia. 10 The newest generation of cTnT assays has a 10- to 100- fold reduced limit of detection, below the 99th percentile of a normal reference population, and these assays are being adopted by a growing number of medical institutions. These assays improve early diagnosis of AMI in the general patient population presenting with acute chest pain. 11–14 However, their diagnostic accuracy for HD patients presenting with chest pain or dyspnea is uncertain. Furthermore, because a substantial proportion of HD patients have elevated cardiac troponins in the absence of acute coronary syndrome, a key clinical challenge is to differentiate a clinically relevant rise in cardiac troponin level from its background elevation. We therefore investigated (1) whether the severity of renal disease is associated with increased baseline high-sensitivity troponin T levels and (2) the diagnostic accuracy of high-sensitivity cardiac troponin T (hs-cTnT) levels measured in patients presenting with acute chest pain or dyspnea at enrollment, and the dynamic change in these levels after 3 hours for AMI in HD patients. MATERIALS AND METHODS Study Population In the West China Hospital of Sichuan University (Chengdu, China), for the period between September 2009 and December 2013, we enrolled HD patients from the nephrology department who on routine predialysis therapy showed signs of chest pain or dyspnea. In addition, on the basis of clinical symptoms, clinicians Accepted for publication April 15, 2015. From the Departments of Laboratory Medicine (Drs Li and Wang L- L; Mss Huang, Wang W-Q, Nie, He, and Song; and Messrs Zhu and Miao) and Nephrology (Drs Shi and Fu), West China Hospital, Sichuan University, Chengdu, China. This study was supported by Roche Diagnostics GmbH in Shanghai (H1311115). The authors have no relevant financial interest in the products or companies described in this article. Reprints: Gui-Xing Li, MM, Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu 610041, China (e-mail: liguixing2014@163.com). Arch Pathol Lab Med—Vol 140, January 2016 High-Sensitivity cTnT Assay for AMI in Hemodialysis Patients—Huang et al 75