Stanford classification of aortic dissection

The Stanford classification, along with the DeBakey classification, is used to separate aortic dissections into those that need surgical repair, and those that usually require only medical management ⁷.

Both the Stanford and DeBakey systems can be used to describe all forms of an acute aortic syndrome (dissection, aneurysm, penetrating atherosclerotic ulcer, and intramural hematoma).

Classification

The Stanford classification divides dissections by the most proximal involvement:

• type A involves any part of the aorta proximal to the origin of the left subclavian artery (A affects ascending aorta)
• type B arises distal to the left subclavian artery origin

A special case that is neither reflected in the original Stanford nor the DeBakey classification are dissections that involve the aortic arch but not the ascending aorta (between 8 and 15% of all aortic dissections ⁴). The nomenclature of these arch dissections has been incoherent for decades and still is.

American surgical consensus (2020) ⁵ defines types A and B according to the location of the intimal tear (both types with additional qualifiers for proximal and distal extent):

• type A: dissections with a tear in the ascending aorta including a segment with the branching of the brachiocephalic trunk
• type B: all dissections with proximal tear distal to the branching of the brachiocephalic trunk

In contrast, a European surgical consensus document (2018) ⁶ recognizes dissections of the arch without the involvement of the ascending aorta as a distinct category, termed "non-A-non-B dissection":

• type A: proximal extent in ascending aorta
• non-A-non-B dissection: retrograde extent or proximal tear in the arch between the brachiocephalic trunk and left subclavian artery
• type B: proximal extent in descending aorta distal to left subclavian artery

Treatment and prognosis

Type A dissections are generally managed surgically as they may result in coronary artery occlusion, aortic incompetence, or rupture into the pericardial sac with resulting cardiac tamponade. Indeed, in the original Stanford series, of the six type A dissections, who were treated medically and died, 4 (perhaps 5) expired due to cardiac tamponade ⁷.

Type B dissections are generally managed medically with blood pressure control.

History and etymology

In 1970, Pat O Daily, H Ward Trueblood, Edward B Stinson, Robert D Wuerflein, and Norman E Shumway, cardiothoracic surgeons at Stanford University School of Medicine, Stanford, California, USA, published a seminal paper on the management of acute aortic dissections ⁷.

They evaluated a cohort of 35 patients with dissecting aortic aneurysms, 30 of whom had acute disease.  When the ascending aorta was involved, surgery resulted in a 28% mortality, versus 67% for the medically treated group. However, if the dissection was descending aorta only, the medical (20%) and surgical (28%) groups had similar outcomes ⁷.