Abstract 4868: A Third Troponin Sample is Not Cost-effective in Patients Suspected of Acute Coronary Syndrome

Abstract

Objective The American Heart Association, the American College of Cardiology, and the European Society of Cardiology joint Task Force guidelines from 2007 suggest that troponins, which is the preferred cardiac biomarker in diagnosing acute myocardial infarction (MI), should be assessed by blood sampling at admission and 6 –9 hours later. In many institutions, a third blood sample 12–24 hours after admission is routinely drawn. The aim of the present study was to evaluate cost-effectiveness of this third blood sample of troponin. Methods We investigated 534 patients who were admitted with chest pain and suspected acute coronary syndrome (ACS). Blood samples for cardiac troponin T (cTnT) analysis were obtained on arrival, after 6 –9 hours, and after 12–24 hours. Acute MI was defined according to the universal definition of MI, with cTnT above 99th percentile, given a coefficient of variability of < 10%. For cost-benefit calculation, total costs per patient were estimated as: One additional cTnT analysis (USD 15) + prolonged hospital stay (0.5 day × USD 1,000). Results Of 534 patients admitted with suspected ACS, 124 patients (23 %) had at least one increased cTnT value. Among these only 4 patients (3.2 %) had cTnT values increased in the third blood sample while the first two samples were normal (p < 0.003). All 4 patients were eligible to be referred to coronary angiography due to their risk profile and electrocardiographic changes even before the result of the third sample became available. Cost-benefit analysis: Incremental costs in our hospital, attributed to the third cTnT sample, can be calculated as: (534 × USD 15 per cTnT sample) + (534−124 pts × 0.5 day × USD 1,000) = USD 213,010. Approximately 1,400 patients with suspected ACS are admitted to our department per year. Thus, the total incremental cost per year is: (1,400/534) × USD 213,010 = USD 558,453. Conclusion: A third blood sample to measure cTnT should not be performed as it adds no further important information regarding the patient’s treatment or investigations plan. On the contrary, it leads to an unnecessary extension of the hospital stay and increased costs.