From the Guidelines
The main difference between Type A and Type B aortic dissections is their location in the aorta, with Type A involving the ascending aorta and Type B involving the descending aorta, which determines treatment approach and prognosis.
Key Differences
- Type A dissections involve the ascending aorta (the first part of the aorta as it leaves the heart) and are considered surgical emergencies requiring immediate open heart surgery to prevent fatal complications like cardiac tamponade, aortic valve insufficiency, and coronary artery compromise 1.
- Type B dissections are limited to the descending aorta (the portion beyond the left subclavian artery) and are often managed medically with blood pressure control using beta-blockers (like metoprolol or labetalol) and other antihypertensives to maintain systolic blood pressure between 100-120 mmHg 1.
Treatment Approach
- Surgery for Type A dissections is typically immediate, while surgery for Type B dissections is typically reserved for complications such as rupture, malperfusion syndromes, or uncontrollable pain 1.
- The Stanford classification system helps clinicians quickly determine the appropriate treatment pathway when faced with this life-threatening condition 1.
Prognosis
- The mortality rate for Type A dissections increases by 1-2% per hour without surgical intervention, highlighting the need for prompt treatment 1.
- Type B dissections have a better prognosis than Type A dissections, but still require careful management to prevent complications 1.
From the Research
Definition of Aortic Dissection
- Aortic dissection is a potentially lethal condition that requires immediate diagnostic and therapeutic intervention 2.
- It involves a tear in the inner layer of the aorta, which can cause the layers of the aorta to separate or dissect 3.
Type A Aortic Dissection
- Type A aortic dissection involves the ascending aorta and is considered a true surgical emergency 3.
- It requires immediate surgical intervention to prevent rupture and death 2, 4.
- Open surgical repair is the standard of care for type A aortic dissection, but thoracic endovascular aortic repair (TEVAR) may be a viable option for patients who are not eligible for open surgical repair 2, 4.
Type B Aortic Dissection
- Type B aortic dissection involves the descending aorta and can be treated with thoracic endovascular aortic repair (TEVAR), open surgery, or best medical treatment 5.
- TEVAR may be favorable in long-term outcomes and can provide morphologic advantages compared to best medical treatment, but it may be associated with a higher stroke rate 5.
- Open surgery seems to be inferior to TEVAR both in short-term and long-term outcomes 5.
Key Differences
- The main difference between type A and type B aortic dissection is the location of the dissection, with type A involving the ascending aorta and type B involving the descending aorta 2, 5.
- The treatment approach also differs, with type A aortic dissection requiring immediate surgical intervention and type B aortic dissection having more treatment options, including TEVAR and best medical treatment 2, 5.