Implications of High-Sensitivity Cardiac Troponin I in Cardiology Clinical Practice

Background: High sensitivity troponin (hsTn) has better sensitivity for myocardial tissue injury detection compared to standard troponin assays, despite lower diagnostic specificity and lack of hsTn assay standardization. Objectives: To examine implications of introducing hsTnI in clinical practice. Methods: We retrospectively collected information of patients presented to a single tertiary cardiac referral centre with suspected acute coronary syndrome (ACS), who had ≥1 hsTnI sample (Abbott ARCHITECT STAT), from 1st June 2016-17th August 2016. Upper range limit (URL), i.e. 99th percentile, was defined as 34.2 ng/L, 15.6 ng/L and 26.2 ng/L for male, female and both gender (“overall”) respectively. Patients were divided into 4 groups - Group 1: hsTnURL but b3 times URL, Group 3: hsTn between 3-5 times URL and Group 4: hsTnN5 times URL. Results: Data from 366 patients was analysed: 227(62.0%), 34(9.3%), 13(3.6%), 92(25.1%) in Group 1, 2, 3 and 4 respectively. In Group 1 to 4, the proportion of ACS was 8.8%, 38.0%, 53.8%, 82.6% and proportion of MI were 0.8%, 29.4%, 53.8%. 82.6%. By using N5 times URL as cut-off, hsTnI has higher specificity and PPV, but lower sensitivity and NPV in diagnosis of ACS {(sensitivity:0.66, specificity:0.0.94, PPV0.83, NPV0.85), with ROC curve AUC:0.896, pb0.001, 95% CI:0.861-0.931}. Our analysis showed serial paired hsTn samples increase the PPV of hsTn to detect ACS. There was no significant difference between using hsTn URL “overall” or “gender-specific” for ACS diagnosis. Kaplan-Meier analysis showed 30-day all-cause mortality in the group with maximal hsTn value NURL is significant higher (pb0.001). Multiple-logistic regression showed that URL of hsTn was an independent variable for 30-day all-cause mortality (p