Medical Image of the Week: Traumatic Aortic Dissection

Figure 1. Chest x-ray demonstrating widened mediastinum with prominence of the aortic arch.

Figure 2. Contrast enhanced CT axial (A, left) and coronal (B, right) views demonstrate descending thoracic aortic dissection with mediastinal hematoma and intimal flap (arrow).

A 21-year-old gentleman with no significant past medical history presented to the emergency department following a highway speed motor vehicle collision. The patient was a restrained passenger in the back seat of the vehicle. On initial evaluation the patient was in stable condition and complaining of acute onset back pain. Physical exam was remarkable for facial contusions, tenderness to palpation about the thoracic and lumbar spine, and a normal neurologic exam.

Imaging with chest x-ray (CXR) revealed widening of the mediastinum with prominence of the aortic arch (Figure 1). Further investigation with contrast enhanced computed tomography (CT) of the chest, abdomen and pelvis showed descending thoracic aortic dissection with mediastinal hematoma (Figure 2). The patient underwent successful endovascular repair and was discharged in stable condition.

Acute traumatic aortic injury is a potentially life-threatening condition requiring prompt evaluation. Initial investigation in the trauma setting often includes CXR imaging (1). CXR findings which should raise suspicion for aortic injury in the appropriate clinical scenario include mediastinal widening, abnormality of the aortic silhouette, and right side tracheal deviation.

CT angiography (CTA) is considered the definitive diagnostic modality in most cases, with high sensitivity and specificity. Mediastinal, periaortic and retrocrural hematoma are findings suggestive of traumatic aortic injury. Definitive findings include contrast extravasation, irregularity of the aortic contour, contained rupture, intramural thrombus, and aortic dissection.

Justin S. Caskey, BS

University of Arizona

College of Medicine

Tucson, Arizona, USA

Reference

1. Nagpal P, Mullan BF, Sen I, Saboo SS, Khandelwal A. Advances in imaging and management trends of traumatic aortic injuries. Cardiovasc Intervent Radiol. 2017 May;40(5):643-54. [CrossRef] [PubMed]

Cite as: Caskey JS. Medical image of the week: traumatic aortic dissection. Southwest J Pulm Crit Care. 2018;16(2):94-5. doi: https://doi.org/10.13175/swjpcc016-18 PDF

Medical Image of the Week: Type A Aortic Dissection Extending Into Main Coronary Artery

Figure 1. Electrocardiogram at presentation showing ST segment elevation in anterior leads (arrows).

Figure 2. Coronary angiogram showing RAO caudal view of left main coronary artery after contrast injection with the smooth proximal linear irregularity suspicious for dissection flap into the left anterior descending artery (arrow).

Figure 3. Panel A: Computed tomography angiogram transverse view showing true lumen and false lumen of both ascending and descending aorta (arrow). Panel B: Computed tomography angiogram sagittal view showing dissection from root into abdominal aorta. 

A 58-year-old woman with no significant past medical history, presented to the emergency department with complains of sudden onset, severe , non-radiating epigastric pain associated with nausea and vomiting. An electrocardiogram (EKG) done in emergency department showed ST segment elevation in the anterior leads (Figure 1). Blood pressure at presentation was 141/79, and she had symmetrical bilateral pulses of the upper extremities, no diastolic murmur, and no neurologic deficit. The patient was taken to catherization laboratory, for ST segment elevated myocardial infarction (STEMI). She was found have aortic dissection extending to the left main coronary artery (Figure 2). Cardiothoracic surgery was called immediately. Computed tomography angiogram (CTA) of the thoracic and abdominal aorta revealed Debakey type 1 aortic dissection. (Figure 3). The patient was taken to the operating room. Unfortunately, the patient suffered pulseless electrical activity (PEA) arrest during anesthesia induction from which she could not be revived.

Aortic dissection is a critical compromise in the lining of the main arterial outflow from the heart (1).  Two theories have been proposed to explain the pathogenesis. A tear in the tunica intima, of the aorta, leads to blood from the aortic lumen surging into the tunica media (2). In contrast, the second theory holds that the vasa vasorum in the more outer portions of the tunica media hemorrhage first and then cause the rupture of the tunica intima (2). The pressure of the pulsatile blood flow extends the dissection, typically in an anterograde fashion (2). Anatomically aortic dissection is classified as Debakey 1,2, and 3 and Stanford A and B (1). Rarely aortic dissections can also extend in a retrograde fashion to reach the coronary ostia (3). Signs of myocardial ischemia including ST segment changes, adversely affect survival outcomes in patients with type A aortic dissection extending to the coronary arteries (4).

Ali Osama Malik MD¹, Oliver Abela MD², Chowdhury Ahsan MD², and Jimmy Diep MD²

¹Department of Internal Medicine

²Department of Cardiovascular Medicine

University of Nevada School of Medicine

Las Vegas, NV USA

References

1. Golledge J, Eagle KA. Acute aortic dissection. Lancet. 2008 Jul 5;372(9632):55-66. [CrossRef] [PubMed]
2. Patel AY, Eagle KA, Vaishnava P. Acute type B aortic dissection: insights from the International Registry of Acute Aortic Dissection. Ann Cardiothorac Surg. 2014 Jul;3(4):368-74. [CrossRef] [PubMed]
3. Neri E, Toscano T, Papalia U, Frati G, Massetti M, Capannini G, et al. Proximal aortic dissection with coronary malperfusion: presentation, management, and outcome. J Thorac Cardiovasc Surg. 2001 Mar;121(3):552-60. [CrossRef] [PubMed]
4. Imoto K, Uchida K, Karube N, Yasutsune T, Cho T, Kimura K, et al. Risk analysis and improvement of strategies in patients who have acute type A aortic dissection with coronary artery dissection. Eur J Cardiothorac Surg. Sep;44(3):419-24; discussion 24-5. [CrossRef] [PubMed]

Cite as: Malik AO, Abela O, Ahsan C, Diep J. Medical image of the week: type A aortic dissection extending into main coronary artery. Southwest J Pulm Crit Care. 2017;14(5):238-9. doi: https://doi.org/10.13175/swjpcc044-17 PDF