Aortic dissection

Author: Mikael Häggström

Planning

Need of modality

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:

• 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.

Choice of investigation

• 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.
• Hemodynamically stable patients without suspected ascending aortic involvement, CT angiography is generally the initial imaging method of choice.

Evaluation

• 

  CT with contrast demonstrating aneurysmal dilation and a dissection of the ascending aorta, as a

Classification

Classification of aortic dissection

		90px
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.

• 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.