cardiovascular disorders
Aortic Dissection
Classification of aortic dissection
Aortic dissections are classified anatomically. TheDeBakey classification systemis most widely used: Type I (50% of dissections): These dissections start in the ascending aorta and extend at least to the aortic arch and sometimes beyond. Type II (35%): These dissections start in and are confined to the ascending aorta (proximal to the brachiocephalic or innominate artery). Type III (15%): These dissections start in the descending thoracic aorta just beyond the origin of the left subclavian artery and extend distally or, less commonly, proximally. Type IIIa dissections originate distal to the left subclavian artery and are confined to the thoracic aorta. Type IIIb dissections originate distal to the left subclavian artery and extend below the diaphragm. TheStanford systemis simpler: Type A: These dissections involve the ascending aorta. Type B: These dissections are confined to the descending thoracic aorta (distal to the left subclavian artery). Although dissection may originate anywhere along the aorta, it occurs most commonly at areas of greatest hydraulic stress, which are the Right lateral wall of the ascending aorta (within 5 cm of the aortic valve) Proximal segment of the descending aorta (just beyond the origin of the left subclavian artery) Rarely, dissection is confined to individual arteries (eg, coronary or carotid arteries), typically in pregnant or postpartum women. 