DIRECT COMPARISON OF HIGH-SENSITIVITY CARDIAC TROPONIN I VERSUS CONVENTIONAL TROPONIN I FOR THE EARLY DIAGNOSIS OF NON-ST ELEVATION MYOCARDIAL INFARCTION

Abstract

Objective: To determine and compare the diagnostic value of high-sensitivitycardiac troponin I with conventional troponin I for the detection of non STelevation acute myocardial Infarction (NSTEMI) in patients with chest pain. Methodology: This is a cross sectional study done in two tertiary care hospitalsPeshawar KPK from August 2016 to February 2017. Patients were enrolledaccording to the inclusion criteria of the study. In this study direct comparison ofthe two assays was done in making the diagnosis of NSTEMI in patients withacute chest pain and to assess the diagnostic utility of the assays used. Themethod used is Electro Chemiluminescene immunoassay “ECLIA” which iscarried out on Elecsys and Cobase immunoassay analyzers (ROCHEDiagnostics) for conventional cardiac troponin I (cTnI) and The Architect STATHigh troponin I (Abbott Diagnostic) for hs-cTnI. Results: Sample size was calculated according to the kit used for detection ofhigh-sensitivity troponin I and conventional troponin I sufficient for 100 samples.Therefore 86 patients sample size was selected and the rest of tests (14) wereused for calibration and control. The study consisted of 86 patients with chestpain typical of acute coronar y syndrome and ST-depression onelectrocardiogram. The mean age of the patients was 59.21 +10.63 years. Ofthese 44 (51.1%) were females. There were 43 (50%) patients with positivehistory and 43 (50%) were with no history of ischemic heart disease. In this study47(54.6%) patients were non-hypertensive, 43 (50%) were overweight, 5 (5.8%)were class 1 obese and only 1 (1.2%) was class 2 obese. About 48 werediagnosed as NSTEMI and 38 were diagnosed as unstable angina. The sensitivityof the cTnI for diagnosing NSTEMI was 60%, specificity was 89.1% with PPV of82.7% and NPV of 72% and sensitivity of hs-cTnI for making diagnosis ofNSTEMI was 94%, specificity was 92% with a PPV of 93.7% and NPV of 92.1%. Conclusion: This study concludes that high- sensitivity cardiac troponin I assayhas more diagnostic utility when compared with conventional troponin I assay. Key Words: Myocardial infarction, Unstable angina, High-sensitivity troponin Iassay, Conventional troponin I assay.