What is the difference between Stanford type A and Stanford type B aortic dissection?

From the Guidelines

The Stanford classification system divides aortic dissections into two types: Type A, which involves the ascending aorta, and Type B, which involves the descending aorta distal to the left subclavian artery, with Type A being a surgical emergency and Type B typically managed medically. The distinction between these two types is crucial for determining management strategy and prognosis, as Type A dissections carry a higher risk of life-threatening complications, including cardiac tamponade, aortic valve insufficiency, and myocardial infarction 1.

Key Differences

• Stanford Type A dissections involve the ascending aorta, regardless of the site of origin, and may extend into the descending aorta, requiring immediate surgical intervention due to the high risk of complications 1.
• Stanford Type B dissections, on the other hand, involve only the descending aorta, without affecting the ascending portion, and are typically managed medically with blood pressure control and pain management unless complications arise 1.

Management Strategies

• Type A dissections are considered surgical emergencies, with surgery usually recommended to reduce mortality rates 1.
• Type B dissections are typically managed medically, unless complications such as malperfusion syndrome, rupture, or uncontrolled pain occur, in which case endovascular or surgical intervention may be necessary 1.

Prognosis

• The mortality rates for Type A dissections are approximately 25% even with surgery, compared to around 10% for Type B dissections with medical management 1.
• The classification system helps clinicians rapidly determine the appropriate treatment pathway when faced with a patient presenting with aortic dissection, prioritizing morbidity, mortality, and quality of life as outcomes 1.

From the Research

Difference between Stanford A and B Aortic Dissection

• Stanford type A aortic dissections involve the ascending aorta, whereas Stanford type B aortic dissections affect the descending thoracic aorta without any involvement of the ascending aorta 2.
• Type B dissections can be further categorized into complicated and uncomplicated dissections, with complicated dissections requiring intervention to limit mortality 2, 3.
• The treatment approach for type B dissections varies depending on the presence of complications, with uncomplicated dissections typically managed medically and complicated dissections requiring thoracic endovascular aortic repair (TEVAR) or open surgical repair 2, 3, 4.

Characteristics of Stanford Type B Aortic Dissection

• Stanford type B aortic dissections can present with complications such as malperfusion syndrome or aortic rupture, which are associated with significant morbidity and mortality if left untreated 3.
• The clinical diagnosis of type B dissection is typically confirmed using CT angiography 3.
• Treatment begins with immediate anti-impulse medical therapy, and acute type B dissections with complications should be repaired with emergent TEVAR 3.

Treatment Options for Stanford Type B Aortic Dissection

• TEVAR has emerged as an alternative to open surgical repair for the treatment of complicated type B dissection, with various societal guidelines proposing TEVAR as the treatment of choice for management of complicated disease 2.
• Open surgical repair is seldom required and reserved only for select cases 3.
• The treatment should be tailored to the morphology of the dissected aorta, with TEVAR reserved for more distal lesions and open arch replacement with the frozen elephant trunk technique for more proximal lesions 5.