While many of us are familiar with spontaneous coronary artery dissection (SCAD) as a common cause of myocardial ischemia in young people, traumatic coronary artery dissection (TCAD) is a rare, potentially life-threatening diagnosis that is challenging to diagnose and often missed in the emergency department (ED), as the clinical features overlap with more common diagnoses that result from blunt chest trauma.¹ It is important to pick up this diagnosis early, as emergency treatment with percutaneous coronary intervention (PCI) to restore blood from to the heart can be lifesaving. In this ACEP Now column, I hope to elucidate some of the key clinical clues of TCAD to maximize your chances of picking it up in your blunt chest trauma patients.

TCAD occurs as a result of rapid deceleration, which increases shear forces on the endothelium of the coronary artery. The stress of the traumatic event causes an acute increase in blood pressure. The combination of shear forces on the coronary artery endothelium and sudden increase in blood pressure results in TCAD. The dissection of the coronary artery that occurs in TCAD may lead to thrombus and/or vasospasm resulting in myocardial infarction and all of its potential complications, including death. Aortic dissection as a result of blunt trauma is often immediately fatal, and if patients do survive to be transported to the ED, it can be difficult to diagnose. By contrast, traumatic aortic dissection does not cause cardiac ischemia like TCAD typically does.

There are several reasons TCAD is often missed in the ED besides it being a rare entity with an incidence of only 0.1 percent.² First, TCAD may result from a relatively low energy mechanism such as a seemingly innocuous blow to the chest in sport. Second, it is predominately diagnosed in young people; 82 percent of patients with acute myocardial infarction after chest trauma are under 45 years of age.³ Another reason TCAD is easily missed in the ED is that the most common cause of TCAD is a motor vehicle crash caused by deceleration and traction or direct impact, and concurrent traumatic injuries in these cases often overshadow the diagnosis.⁴ Patients may present with altered mental status, rendering them unable to convey symptoms of cardiac ischemia. Generalized chest pain has a broad differential diagnosis in the polytrauma patient. Other cardiac injuries are often considered first, such as cardiac contusion, dysrhythmias, and cardiac tamponade. Finally, symptoms of TCAD may not present for several hours, days, or weeks after the inciting traumatic event, as the rate of expansion of the false lumen may vary considerably.⁵

When Should We Consider the Diagnosis?

Given how easy it is to miss TCAD and how rare it is, when should we consider the diagnosis? TCAD should be considered in a young person with a history of recent chest trauma followed hours to weeks later with anginal symptoms plus any combination of ischemic ECG changes, troponin elevation, or wall motion abnormalities on point-of-care ultrasound (POCUS). Typical angina symptoms after trauma in a young patient without traditional cardiac risk factors warrant a work-up for TCAD. Patients complaining of chest pain after sustaining blunt chest trauma should undergo a prompt cardiovascular work-up with ECG and serial troponins to screen for cardiac contusion, dysrhythmias, and for cardiac ischemia as a result of TCAD. The Eastern Association for the Surgery of Trauma (EAST) recommends that an ECG and cardiac biomarkers be obtained for all patients in whom blunt cardiac injury is suspected.⁶ A key pitfall in patients who have recently sustained trauma to the chest is assuming that a borderline ECG and positive troponin are due only to cardiac contusion, which does not warrant activation of the cardiac catheterization lab. Similarly, patients with multiple rib fractures, a risk factor for TCAD, may have their chest pain attributed solely to the fractures, and the diagnosis of TCAD may be overlooked. Patients with angina-type symptoms, ongoing dyspnea after initial treatment of other traumatic injuries, cardiac dysrhythmia, and/or elevated troponin should be considered for CT angiography of the coronary arteries and/or angiography in the cath lab. Even a borderline ischemic-appearing ECG and positive troponin should trigger the provider to consider the diagnosis of TCAD and discuss this possibility with an interventional cardiologist for consideration of emergency coronary angiography.

PCI is the most common treatment done to repair the coronary artery dissection in patients who have sustained a myocardial infarction. In the very rare case of left main coronary artery dissection, coronary artery bypass grafting (CABG) is the treatment of choice. In those patients with TCAD who are stable without evidence of coronary ischemia, the treatment of choice is often conservative, with observation and repeat angiography.⁶

It is my hope that increasing awareness of TCAD by emergency providers will improve the diagnostic yield and improve morbidity and mortality in these patients. If we consider TCAD in young people with a history of recent chest trauma followed hours to weeks later with anginal symptoms plus any combination of ECG changes, troponin elevation, or ischemic PoCUS findings, the emergency medicine community will save many lives!

A special thanks to Dr. Ian Chernoff, the guest expert on the EM Cases podcast that inspired this column.

Dr. Helman is an emergency physician at North York General Hospital in Toronto. He is an assistant professor at the University of Toronto, Division of Emergency Medicine, and the education innovation lead at the Schwartz/Reisman Emergency Medicine Institute. He is the founder and host of Emergency Medicine Cases podcast and website.

References

1. Hayes SN, Kim ESH, Saw J, et al. Spontaneous coronary artery dissection: current state of the science: a scientific statement from the American Heart Association. Circulation. 2018;137(19):e523-e557.
2. Haywood ST, Patel K, Gallo D, et al. Throws of Death: Traumatic Coronary Artery Dissection Resulting From Jiu Jitsu Training. J Emerg Med. 2020;58(1):63-66.
3. Christensen MD, Nielsen PE, Sleight P. Prior blunt chest trauma may be a cause of single vessel coronary disease; hypothesis and review. Int J Cardiol. 2006;108(1):1-5.
4. Lobay KW, MacGougan CK. Traumatic coronary artery dissection: a case report and literature review. J Emerg Med. 2012;43(4):e239-e243.
5. Mubang RN, Hillman Terzian WT, et al. Acute myocardial infarction following right coronary artery dissection due to blunt trauma. Heart Views. 2016;17(1):35-38.
6. Clancy K, Velopulos C, Bilaniuk JW, et al. Screening for blunt cardiac injury: an Eastern Association for the Surgery of Trauma practice management guideline. J Trauma Acute Care Surg. 2012;73(5 Suppl 4):S301-S306.