Using historical cardiac troponins to identify patients at a high risk of myocardial infarction

Abstract

Objective: Many patients who present with chest pain have previous measurements of high-sensitivity cardiac troponin T (hs-cTnT). The clinical usefulness of incorporating these measurements in identifying patients who are at a high risk of myocardial infarction (MI) is unknown. We investigated if the relative change between a historical hs-cTnT and the admission hs-cTnT could improve early identification of patients with a high risk of MI.

Methods: We included all patients presenting with chest pain to seven different emergency departments (EDs) in Sweden from December 2009 to December 2016, who had at least one hs-cTnT measurement at the presentation and at least one available prior measurement. We used logistic regression to investigate the diagnostic performance of using various combinations of current and historical hs-cTnT measurements in diagnosing MI within 30 days.

Results: A total of 27 809 visits were included, among whom 2686 (9.7%) had an MI within 30 days. A cut-off value for historical hs-cTnT-adjusted admission hs-cTnT with similar specificity (91.2%) as an admission hs-cTnT of ≥52 ng/L identified 4% more MIs (43% vs 39%) and had a higher positive predictive value, 42.6% (95% CI, 41.0% to 44.3%) vs 38.9% (95% CI 37.4% to 40.4%), as well as a higher positive likelihood ratio, 6.95 (95% CI 6.69 to 7.22) vs 5.95 (95% CI 5.73 to 6.18). Among patients with an admission hs-cTnT of <52 ng/L who were classified as high-risk patients when incorporating past hs-cTnT measurements, 28% suffered an MI.

Conclusions: Historical hs-cTnT levels can be used with admission hs-cTnT to improve early risk stratification of MI in the ED.

Keywords: Biomarkers; Chest Pain; Epidemiology; Myocardial Infarction.

Figure 1

Selection of the study population. hs-cTnT, high-sensitivity cardiac troponin T; STEMI, ST-segment elevation myocardial infarction.

Figure 2

Receiver operating characteristic curves (ROCs) of the different hs-cTnT-based strategies for diagnosing myocardial infarction. (A) All visits. (B) vVsits with 0-hour hs-cTnT 12–51 ng/L. (C) Visits with 0-hour hs-cTnT ≥52 ng/L. hs-cTnT, high-sensitivity cardiac troponin T.

Figure 3

Adjusted risk of myocardial infarction, all-cause mortality and cardiovascular mortality within tertiles of relative Δhs-cTnT and historical-adjusted hs-cTnT. The model was adjusted for the following covariates: age, sex, eGFR, prior MI, heart failure, prior stroke, prior chronic obstructive pulmonary disease, atrial fibrillation, diabetes, and treatment with aspirin, P2Y12 inhibitors, oral anticoagulants, beta-blockers, angiotensin-converting enzyme inhibitor/angiotensin receptor blockers, and statins. eGFR, estimated glomerular filtration rate; hs-cTnT, high-sensitivity cardiac troponin T; MI, myocardial infarction.

Figure 4

Diagnostic performance of historical-adjusted hs-cTnT for diagnosing myocardial infarction in patients risk-stratified according to the ESC 0/1-hour algorithm. The numbers are shown with percent in parentheses. Note: No patients had a very low risk according to the 0-hour hs-cTnT (ie, a 0-hour hs-cTnT <5 ng/L), as only patients with a positive Δhs-cTnT were included. FN, false negative; hs-cTnT, high-sensitivity cardiac troponin T; LR+, positive likelihood ratio; MI, myocardial infarction; PPV, positive predictive value; TP, true positive.