Traumatic aortic rupture pathophysiology
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Pathophysiology
Sheer Mechanism
The injury is usually caused by high speed impacts such as those that occur in vehicle collisions and serious falls. The location of the initial aortic tear is usually at the point in the proximal descending aorta with the greatest sheer where the relatively free and mobile aortic arch joins to the fixed descending aorta (ligamentum arteriousm). By far the most common site for tearing in traumatic aortic rupture is the aortic isthmus, near where the left subclavian artery branches off from the aorta.[1][2] This junction of the free and fixed part of the aorta is at the greatest risk of transection as a result of the shearing forces due to sudden deceleration.[3] Frontal or side impacts in motor vehicle accidents and falls from substantial heights pose the greatest risk of sheer.
The aorta may also be torn at the point where it is connected to the heart. The aorta may be completely torn apart from the heart, but patients with such injuries very rarely survive for very long after the injury; thus it is much more common for hospital staff to treat patients with partially torn aortas. When the aorta is partially torn, it may form a "pseudoaneurysm". In patients who do live long enough to be seen in a hospital, a majority have only a partially torn blood vessel, with the layer called the adventitia still intact. In some of these patients, the adventitia and nearby structures within the chest may serve to prevent severe hemorrhage.
Compressive Mechanism
Extrinsic compression of the aorta between the sternum and the spine may contribute at least in part to aortic rupture.
Elevated Intra-aortic Pressure Mechanism
A sudden, dramatic rise in intra-luminal aortic pressure at the time of impact may contribute to aortic rupture.
References
- ↑ Phillips BJ (2001). "Traumatic Rupture Of The Thoracic Aorta: An Endoluminal Approach". The Internet Journal of Thoracic and Cardiovascular Surgery. 4 (1). ISSN 1524-0274.
- ↑ McKnight JT, Meyer JA, Neville JF (1964). "Nonpenetrating Traumatic Rupture of the Thoracic Aorta". Ann. Surg. 160: 1069–72. PMID 14246145.
- ↑ Rittenhouse EA, Dillard DH, Winterscheid LC, Merendino KA (1969). "Traumatic rupture of the thoracic aorta: a review of the literature and a report of five cases with attention to special problems in early surgical management". Ann. Surg. 170 (1): 87–100. PMID 5789533.