How are aortic dissections categorized?

From the Guidelines

Aortic dissections are primarily categorized using two classification systems: the Stanford and DeBakey systems, with the Stanford classification being the most widely used and recommended by the 2014 ESC guidelines 1. The Stanford classification divides dissections into type A and type B.

• Type A involves the ascending aorta (regardless of where the tear begins) and requires immediate surgical intervention due to high mortality risk.
• Type B affects only the descending aorta (distal to the left subclavian artery) and is typically managed medically unless complications arise. The DeBakey system offers more detail with three types:
• type I (involving both ascending and descending aorta),
• type II (ascending aorta only), and
• type III (descending aorta only, with type IIIa limited to the thoracic aorta and type IIIb extending to the abdominal aorta). These classifications are crucial for determining appropriate treatment strategies, with type A/DeBakey I-II generally requiring emergency surgery while uncomplicated type B/DeBakey III dissections often managed with blood pressure control and close monitoring, as supported by the 2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines 1. The categorization reflects the anatomical involvement and helps predict complications, with proximal dissections carrying higher risks of cardiac tamponade, aortic valve insufficiency, and coronary artery compromise, as noted in the 2015 Annals of Emergency Medicine study 1. It is essential to note that the Stanford classification is preferred due to its simplicity and clinical relevance, as stated in the 2014 ESC guidelines 1, and should be used as the primary classification system for aortic dissections.

From the Research

Categorization of Aortic Dissections

Aortic dissections can be categorized using various classification systems, including:

• Stanford classification: divides aortic dissections into two types, Type A and Type B, based on the location of the tear [ 2, 3 ]
• DeBakey classification: not explicitly described in the provided studies, but mentioned as a traditional classification system 4
• Type-Entry-Malperfusion (TEM) classification: a newer classification system that aims to more accurately define and risk-stratify patients with aortic dissection 4
• Modified classification: used in the study 2 to classify Type A dissections into three subtypes (A1, A2, A3) based on pathological changes of the aortic root, and Type B dissections into three subtypes (B1, B2, B3) based on dilated extension of the proximal descending aorta

Subtypes of Aortic Dissections

The study 2 classified Type A dissections into three subtypes:

• Type A1: no pathological change
• Type A2: mild pathological change
• Type A3: severe pathological change Type B dissections were classified into three subtypes:
• Type B1: no dilation confined to the proximal thoracic descending aorta
• Type B2: aneurysm in the thoracic descending aorta
• Type B3: aneurysm in the thoracic descending and abdominal aorta Additionally, the study 2 classified Type B dissections into two types:
• Type BC: complex type
• Type BS: simple type

Classification Systems and Treatment

The choice of classification system can impact treatment decisions, with different systems guiding medical optimization or surgery 4, 3. The Stanford classification is widely used to distinguish between Type A and Type B dissections, with Type A dissections typically requiring surgical intervention and Type B dissections often managed medically 2, 3. However, the TEM classification system may offer advantages in risk stratification and guiding treatment 4.