Elevated Cardiac Troponin Is Most Often Associated With Type 2 Myocardial Infarction in Trauma Patients

Introduction Cardiac troponin (cTn) forms an essential part of the diagnostic criteria for myocardial infarction (MI). Type 1 MI is a primary coronary arterial event, whereas type 2 MI is due to coronary oxygen supply/demand mismatch, which is common in trauma patients. In addition, cTn may be elevated for many reasons other than MI. cTn elevations in trauma may not be specific for MI amenable to revascularization. The aim of this study is to determine which subset of trauma patients benefits from measuring cTn, and which patients with elevated cTn benefit from ischemic workup. Methods This is a retrospective cohort study. All patients on the trauma service of a level 1 trauma center with cTn elevated above the upper reference value of 0.032 ng/ml from July 2017 through December 2020 were selected. Baseline characteristics were recorded. The main outcomes were cardiology determination of the etiology of elevated cTn and patient survival. Logistic regression was used for multivariate analysis. Results One hundred forty-seven (147; 1.1%) of 13746 trauma patients had maximum cTn over the 99th percentile. Forty-one (27.5%) of the 147 had ischemic changes on electrocardiogram (ECG). Sixty-four (43.0%) had chest pain. In 81 (55.1%) cases, cTn was ordered without a clearly justified indication. One hundred thirty-seven patients (93.3%) received a cardiology consult. Two (1.5%) of 137 patients had a type 1 MI, which was diagnosed by ECG and clinical symptoms before cTn results were available. One hundred thirty-five patients were evaluated for cardiac ischemia based on elevated cTn. In 91 (66.4%) cases, the elevated cTn was attributed to a cardiac oxygen supply/demand mismatch. The etiology was cardiac contusion for 26 (19.0%), with the rest attributed to various other trauma-related causes. The cardiology consult changed management for 90 (65.7%) patients, mainly consisting of further evaluation by echocardiogram for 78 (57.0%) patients. Elevated cTn was a significant independent predictor of death with an adjusted odds ratio of 2.6 (p=0.002). Conclusion Isolated cTn values in trauma are most often due to type 2 MI resulting from trauma-related issues, such as tachycardia and anemia, which affect myocardial oxygen supply and demand. Changes in management generally consisted of further workup and interventions such as monitoring and pharmacologic treatment. Elevated cTn in this cohort never led to revascularization but was valuable to identify patients who required more intensive monitoring, longer-term follow-up, and supportive cardiac care. More selective ordering of cTn would improve specificity for patients requiring specialized cardiac care.