Minimal aortic injuries are traumatic aortic lesions that usually involve the intima and are recognised more frequently due to the use of high-resolution imaging.
Minimal aortic injuries account for 10-28% of all blunt traumatic aortic injuries 1,6,7. The proportion of this type of aortic injury among overall blunt traumatic aortic injuries is higher in more recent studies due to the widespread use of multidetector computed tomography (MDCT) for trauma emergencies.
Minimal aortic injuries are mild forms of blunt traumatic aortic injury. Various definitions of minimal aortic injury have been used in literature. They were originally defined as small (<1 cm) intimal flaps with no or minimal periaortic haematoma. Some authors defined the lesions as post-traumatic abnormalities of the inner aortic wall projecting into the lumen with no evidence of an abnormality to the outer contour of the aorta.
Like other blunt traumatic aortic injuries, proposed mechanisms include:
- rapid deceleration
- shearing forces
- osseous pinch
- sudden increase in hydrostatic forces or water-hammer phenomenon
Injuries limited to the intimal layer usually do not compromise the resistance of the aortic wall and may heal spontaneously by endothelialization.
CT angiography is the investigation of choice. With improvements in imaging technology, which allow a thinner CT slice thickness, minimal aortic injuries are being diagnosed more frequently.
Minimal aortic injuries can present with:
- intimal irregularity or flap
- most common imaging appearance (~80%) 1
- rounded, triangular or focal thin membrane-like filling defects
- intraluminal aortic thrombus
- intramural haematoma (~10%) 1
Treatment and prognosis
Since intimal injuries may resolve spontaneously, minimal aortic injuries are amenable to non-operative or medical management and can be treated conservatively with anti-hypertensives, anticoagulants or both depending on the coexisting injuries. Limited data on the natural history of this type of aortic injury necessitates close imaging surveillance for detection of any potential complication or adverse evolution of the minimal aortic injury. In some institutions, endovascular repair is another option for treatment.
Normal anatomic variants and conditions that can mimic minimal aortic injuries on CT include:
- breathing, arterial pulsation and other motion artefacts
- streaming of contrast
- ductus diverticulum and ductus remnant
- infundibulum of branch vessel
- 1. Gunn ML, Lehnert BE, Lungren RS, Narparla CB, Mitsumori L, Gross JA, Starnes B. Minimal aortic injury of the thoracic aorta: imaging appearances and outcome. Emergency radiology. 21 (3): 227-33. doi:10.1007/s10140-013-1187-8 - Pubmed
- 2. Kidane B, Abramowitz D, Harris JR, DeRose G, Forbes TL. Natural history of minimal aortic injury following blunt thoracic aortic trauma. Canadian journal of surgery. Journal canadien de chirurgie. 55 (6): 377-81. doi:10.1503/cjs.007311 - Pubmed
- 3. Heneghan RE, Aarabi S, Quiroga E, Gunn ML, Singh N, Starnes BW. Call for a new classification system and treatment strategy in blunt aortic injury. Journal of vascular surgery. 64 (1): 171-6. doi:10.1016/j.jvs.2016.02.047 - Pubmed
- 4. Paul JS, Neideen T, Tutton S, Milia D, Tolat P, Foley D, Brasel K. Minimal aortic injury after blunt trauma: selective nonoperative management is safe. The Journal of trauma. 71 (6): 1519-23. doi:10.1097/TA.0b013e31823b9811 - Pubmed
- 5. Cullen EL, Lantz EJ, Johnson CM, Young PM. Traumatic aortic injury: CT findings, mimics, and therapeutic options. Cardiovascular diagnosis and therapy. 4 (3): 238-44. doi:10.3978/j.issn.2223-3652.2014.06.02 - Pubmed
- 6. Mosquera VX, Marini M, Gulías D, Cao I, Muñiz J, Herrera-Noreña JM, López-Pérez JM, Cuenca JJ. Minimal traumatic aortic injuries: meaning and natural history. Interactive cardiovascular and thoracic surgery. 14 (6): 773-8. doi:10.1093/icvts/ivs095 - Pubmed
- 7. Malhotra AK, Fabian TC, Croce MA, Weiman DS, Gavant ML, Pate JW. Minimal aortic injury: a lesion associated with advancing diagnostic techniques. The Journal of trauma. 51 (6): 1042-8. Pubmed
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