ABC | Volume 110, Nº1, January 2018

Original Article Sensitive Troponin I Assay in Patients with Chest Pain – Association with Significant Coronary Lesions with or Without Renal Failure Alexandre de Matos Soeiro, Danielle Menosi Gualandro, Aline Siqueira Bossa, Cindel Nogueira Zullino, Bruno Biselli, Maria Carolina Feres de Almeida Soeiro, Tatiana de Carvalho Andreucci Torres Leal, Carlos Vicente Serrano Jr., Mucio Tavares de Oliveira Junior Unidade Clínica de Emergência - InCor – HCFMUSP, São Paulo, SP – Brazil Mailing Address: Alexandre de Matos Soeiro • Rua João Moura, 870, apto 192b. CEP 05412-002, Pinheiros, São Paulo, SP – Brazil E-mail: alexandre.soeiro@bol.com.br Manuscript received January 05, 2017, revised mansucript July 25, 2017, accepted July 27, 2017 DOI: 10.5935/abc.20170182 Abstract Introduction: Despite having higher sensitivity as compared to conventional troponins, sensitive troponins have lower specificity, mainly in patients with renal failure. Objective: Study aimed at assessing the sensitive troponin I levels in patients with chest pain, and relating them to the existence of significant coronary lesions. Methods: Retrospective, single-center, observational. This study included 991 patients divided into two groups: with (N = 681) and without (N = 310) significant coronary lesion. For posterior analysis, the patients were divided into two other groups: with (N = 184) and without (N = 807) chronic renal failure. The commercial ADVIA Centaur ® TnI-Ultra assay (Siemens Healthcare Diagnostics) was used. The ROC curve analysis was performed to identify the sensitivity and specificity of the best cutoff point of troponin as a discriminator of the probability of significant coronary lesion. The associations were considered significant when p < 0.05. Results: The median age was 63 years, and 52% of the patients were of the male sex. The area under the ROC curve between the troponin levels and significant coronary lesions was 0.685 (95% CI: 0.65 – 0.72). In patients with or without renal failure, the areas under the ROC curve were 0.703 (95% CI: 0.66 – 0.74) and 0.608 (95% CI: 0.52 – 0.70), respectively. The best cutoff points to discriminate the presence of significant coronary lesion were: in the general population, 0.605 ng/dL (sensitivity, 63.4%; specificity, 67%); in patients without renal failure, 0.605 ng/dL (sensitivity, 62.7%; specificity, 71%); and in patients with chronic renal failure, 0.515 ng/dL (sensitivity, 80.6%; specificity, 42%). Conclusion: In patients with chest pain, sensitive troponin I showed a good correlation with significant coronary lesions when its level was greater than 0.605 ng/dL. In patients with chronic renal failure, a significant decrease in specificity was observed in the correlation of troponin levels and severe coronary lesions. (Arq Bras Cardiol. 2018; 110(1):68-73) Keywords: Troponin I; Chest Pain; Coronary Artery Disease; Renal Insufficiency, Chronic; Biomarkers. Introduction In recent years, cardiology has witnessed the constant development of several biomarkers, of which, current sensitive troponins and high-sensitivity troponins, widespread in Brazil and Europe, stand out. 1 However, despite the huge gain in sensitivity, allowing early detection of a minimum threshold of myocardial lesion in patients presenting to the emergency department with chest pain, there was a reduction in specificity, which resulted in several patients with non-cardiological or non‑coronary problems undergoing unnecessary and even harmful antithrombotic therapy and invasive coronary stratification. 2-5 The adequate troponin level to be considered for the correct interpretation of clinical findings depends on the patient’s characteristics and on the troponin assay used, and should be ideally individualized for each service. 2-4,6 Thus, this study was aimed at assessing the current sensitive troponin I levels for patients with chest pain, in addition to relating them to the existence of significant coronary lesions both in the presence and absence of chronic renal failure in the sample selected. Methods Study population This is a retrospective, single-center, observational study, including 991 patients with chest pain admitted to the emergency department of a high-complexity tertiary cardiology center, between May 2013 and May 2015. All patients with chest pain undergoing coronary angiography for suspected unstable angina or non-ST-elevation 68