Role of Troponins in haemodynamically stable penetrating injuries to the cardiac box, is it helpful?

Abstract Background Cardiac trauma is associated with a high mortality rate, but a subset of the patients presents with normal vital signs in the emergency department. Identification of cardiac injuries in these patients can be a challenge. Many investigative modalities have been used to identify penetrating cardiac injury patients. Most of these tests are expensive, specialised and not easily accessible. However, the role of Troponins in penetrating cardiac injury has not been defined. We hypothesised that cardiac troponins have a negative predictive value in penetrating cardiac injuries. Materials and methods We retrospectively reviewed all patients who presented to the Charlotte Maxeke Academic Hospital trauma unit over 22 months (January 2018 to October 2020). Patients were identified using the hospital database. All patients with penetrating cardiac trauma to the cardiac zone above the age of 16 years were included. The patient’s demographics, mechanism of injury, injury severity score, vital signs, investigation findings, troponin levels, final diagnosis, type of operation, length of hospital stay, morbidities and mortalities were recorded. Results There was a total of 173 patients identified; 6 were females. The median age was 30 years. Most patients (160/173, 92%) had stab wounds. The median Injury Severity Score (ISS) was 12.8. Most patients sustained stab wounds on the left side of the chest (n=90), 52%. Initial ultrasound was positive for pericardial fluid in 10% of patients (n=18). The sensitivity of cardiac troponins was 19.7%, and the specificity was 98.2%. The negative and positive predictor values were 69.2% and 85.7%, respectively. The mean initial Troponins level was 50 ng/L. The mean repeat troponins were 450 ng/L in those patients with cardiac injuries. The Troponins were significantly different in those with cardiac injuries and those without cardiac injuries. In patients who had a cardiac injury, the right ventricle (3.5%) was the most commonly injured chamber, followed by the left ventricle (2.3%) and Right atrium (0.6%). Two patients sustained myocardial injuries without chamber penetration. The overall mortality rate was 0,6%(n=1). Fifty percent of the patients (n=87) were discharged home from the emergency department, 21.8% were admitted to the ward (n=38), and 15.5% (n=27) were admitted to the Trauma ICU. The average hospital stay was one day for patients with a stab to the precordium. Conclusion Troponins can be used to evaluate cardiac injuries in haemodynamically stable patients with penetrating chest trauma. It is highly specific for cardiac injuries (98%). More prospective data is needed to confirm our findings and then extend to clinical practice, especially in resource-limited environments.