Consequences of high-sensitivity troponin T testing applied in a primary care population with chest pain compared with a commercially available point-of-care troponin T analysis : an observational prospective study

摘要

BACKGROUND:There is a demand for a highly sensitive and specific point-of care test to detect acute myocardial infarction (AMI). It is unclear if a high-sensitivity troponin assay will have enough discriminative power to become a decision support in primary care. The aim of this study was to evaluate a high-sensitivity troponin T assay performed in three primary health care centres in southeast Sweden and to compare the outcome with a point-of-care troponin T test.METHODS:This study included 115 patients who consulted their general practitioner for chest pain, dyspnoea on exertion, unexplained weakness and/or fatigue in the last 7days. Troponin T was analysed by a point-of-care test and a high-sensitivity method together with N-terminal pro-B-type natriuretic peptide (NT-proBNP) and creatinine. All patients were checked for AMI or unstable angina (UA) within 30days of study enrolment. Univariate and multivariate logistic regression was carried out to examine possible connections between troponin T[greater than or equal to]15ng/L, clinical variables and laboratory findings at baseline. In addition, 21 patients with troponin T[greater than or equal to]15ng/L and no signs of AMI or UA were followed up for 2-3years.RESULTS:Three patients were diagnosed with AMI and three with UA. At the [greater than or equal to]15ng/L cut-off, the troponin T method had 100% sensitivity, 75% specificity for AMI and a positive predictive value of 10%. The troponin T point-of-care test missed one case of AMI and the detection limit was 50ng/L. Troponin T[greater than or equal to]15ng/L was correlated to age [greater than or equal to]65years (odds ratio (OR), 10.9 95% CI 2.28-51.8) and NT-proBNP in accordance with heart failure (OR 8.62 95% CI 1.61-46.1). Fourteen of the 21 patients, without signs of AMI or UA at baseline, still had increased troponin T at follow-up after 2-3years.CONCLUSIONS:A high-sensitivity troponin T assay could become useful in primary care as a point-of-care test for patients <65years. For patients older than 65-70years, a higher decision limit than [greater than or equal to]15ng/L should be considered and used in conjunction with clinical parameters and possibly with NT-proBNP.