CT of aortic dissection

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Author: Mikael Häggström [notes 1]

Planning

Need of investigation

According to a clinical prediction rule of the American Medical Association, symptoms that best determine the risk of acute aortic dissection in patients with acute chest pain, acute back pain, or both are:[1][2]

  • Pain in the chest or abdomen with immediate onset and a tearing or ripping character
  • Differentials in pulse (absence of a proximal extremity or carotid pulse) and/or blood pressure (>20 mmHg difference between the right and left arm)
  • Mediastinal and/or aortic widening on chest radiography

Probability of dissection was found to be relatively low (7%) only in the absence of all 3 variables.[1]

Choice of modality

  • Hemodynamically stable patients without suspected ascending aortic involvement, CT of aortic dissection is generally the initial imaging method of choice.[2]
  • For hemodynamically unstable patients or where a dissection of the ascending aorta is suspected, transesophageal echocardiography (TEE) is suggested as the first investigation of choice.[2]

Settings

  • It should be performed as a CT angiography
  • The protocol needs to include a non-contrast thorax in order to detect any intramural hematomas.
  • It should cover the entire aorta, even if symptoms are limited to the thorax (in order to see the extent in case a dissection is detected).

Evaluation

Classification

Classification of aortic dissection
Aortic dissection of DeBakey type I.png Aortic dissection of DeBakey type II.png Aortic dissection of DeBakey type III.png
Stanford A (Proximal) Stanford B (Distal)
DeBakey I DeBakey II DeBakey III

The Stanford classification is divided into two groups, A and B, depending on whether the ascending aorta is involved.[3]

  • A – involves the ascending aorta and/or aortic arch, and possibly the descending aorta. The tear can originate in the ascending aorta, the aortic arch, or more rarely, in the descending aorta.
  • B – involves the descending aorta or the arch (distal to the left subclavian artery), without the involvement of the ascending aorta.

The Stanford classification is more useful than the older DeBakey system as it follows clinical practice, as type A ascending aortic dissections generally require primary surgical treatment, whereas type B dissections can initially be treated conservatively.

Notes

  1. For a full list of contributors, see article history. Creators of images are attributed at the image description pages, seen by clicking on the images. See Radlines:Authorship for details.

References

  1. 1.0 1.1 von Kodolitsch, Yskert; Schwartz, Ann G.; Nienaber, Christoph A. (2000). "Clinical Prediction of Acute Aortic Dissection ". Archives of Internal Medicine 160 (19): 2977. doi:10.1001/archinte.160.19.2977. ISSN 0003-9926. 
  2. 2.0 2.1 2.2 James H Black, III, Warren J Manning. Clinical features and diagnosis of acute aortic dissection. UpToDate. This topic last updated: Feb 16, 2018. Topic 8190 Version 29.0}}
  3. "Management of acute aortic dissections ". Ann Thorac Surg. 10 (3): 237–47. Sep 1970. doi:10.1016/S0003-4975(10)65594-4. PMID 5458238.