Long-Term Major Adverse Cardiovascular Events in Patients "Appropriately" Tested for Troponin Assays in Emergency Department.

Cardiac biomarkers like troponin have become essential for detecting myocardial ischemia, a hallmark of the acute coronary syndrome (ACS), in the emergency department (ED). However, inappropriate and excessive biomarker testing can lead to false positive results, patient anxiety, and unnecessary treatment. Our study aimed to develop an appropriateness criterion for troponin testing and examine the long-term major adverse cardiac events (MACE) of patients tested with troponin in the ED. We retrospectively evaluated 407 patients who underwent troponin testing at a tertiary-care northeastern US hospital. The majority (n = 252, 62%) of troponin testing was appropriate, with the remainder deemed inappropriate. Baseline characteristics were equally distributed between the 2 groups. Of the appropriately ordered troponins, 34% were positive compared to 28% of the inappropriately ordered troponins (range 0.04-0.10 ng/mL). Patients were followed over 540 days. MACE occurred in 21% and 10% of patients in the appropriate and inappropriate groups, respectively. Unlike the inappropriate group (3.5%), 96% of the events in the appropriate group occurred within the first 200 days. Patients in the appropriate group were at an increased adjusted risk of MACE (HR 2.55, 95% CI (1.59-4.08), P < 0.001) on long-term follow-up. In addition, MACE was comparable between patients with positive and negative troponins in the inappropriate group (HR 1.46, 95% CI (0.28-7.71), P = 0.65). Our study supports judicious troponin testing and the need for robust appropriateness criteria for ordering troponin in the ED to avoid overdiagnosis and inappropriate testing.