From the Guidelines
Approximately 2% of type B (Stanford type B) aortic dissections will propagate and become type A (Stanford type A) aortic dissections.
Key Points
- The propagation of type B dissections to type A dissections is a rare occurrence, with a reported incidence of 2% in patients with type B (type III) dissection with communication 1.
- The risk of propagation is higher if the aortic arch is involved, with increased mortality rates compared to type B dissections limited to the descending aorta.
- The prognosis for type B dissection is generally better than for type A dissection, with reported 1-year survival rates of 85% and 34%, respectively 1.
- Spontaneous healing of aortic dissection can occur, but it is rare, with reported rates of wall thickening as a sign of healing in only 4% of patients in the European Cooperative study 1.
- Complete thrombosis of the false lumen is sometimes observed and appears to be a prerequisite for complete healing, with the extent of thrombus formation being an important factor 1.
Important Considerations
- The management of aortic dissection involves life-long beta-adrenergic blockade, periodic routine imaging of the aorta, and prophylactic replacement of the aortic root before diameter exceeds 5.0 cm in patients with a family history of dissection 1.
- Surgical techniques do not result in progression of thrombus formation in patients with aortic dissection, and replacement of the ascending aorta alone cannot eliminate flow in the false lumen 1.
From the Research
Aortic Dissection Propagation
- The provided studies do not directly address the percentage of type B (Stanford type B) aortic dissections that will propagate and become type A (Stanford type A) aortic dissections.
- However, it is mentioned in the study 2 that an immediate open surgical procedure is needed for dissection of the ascending aorta, given the high mortality rate.
- The study 3 reports on a patient who was readmitted 1 month later because the dissection extended into the ascending aorta, but this is a single case and not a comprehensive analysis of propagation rates.
- The other studies 4, 5, 6 focus on the management and treatment of type B aortic dissections, but do not provide information on the propagation rates to type A dissections.
Management of Type B Aortic Dissections
- The studies suggest that the management of type B aortic dissections depends on the severity and location of the dissection, as well as the presence of complications such as rupture, malperfusion, or ongoing pain 4, 5, 6.
- Thoracic endovascular aortic repair (TEVAR) is considered a treatment option for complicated type B dissections, and is also being considered for select patients with initially uncomplicated dissections 6.
- The study 2 suggests that open surgical repair is optimal for treating type A (ascending aorta) aortic dissections, while TEVAR may be optimal for treating type B (descending aorta) dissections.
- The study 3 reports on the feasibility and safety of endovascular stent-graft placement in treating Stanford type B aortic dissection, with promising results.