Illustration of typical descending aortic dissection demonstrating entry tear and expansion of false lumen resulting in avulsion of left renal artery.
Aortic dissection results from a tear in the aortic intima leading to blood dissecting between the media and adventitia of the aorta. The separation of the media and adventitia results in the creation of a new, false lumen within the aorta. As the false lumen expands it may cause avulsion of branch vessels from the true lumen of the aorta thus resulting in ischemia to the affected vascular beds.
Dissection may affect the ascending aorta and aortic arch (termed a Stanford Type A dissection) or the descending aorta (Stanford Type B dissection). Given the risk of cardiac or cerebral ischemia with ascending aortic dissection, all patients with ascending aortic dissections are managed with emergent aortic repair. In contrast, the standard of care for descending aortic dissections involves medical management of blood pressure to decrease the risk of dissection propagation. Surgery for patients with descending aortic dissections is reserved for those patients experiencing end-organ or extremity malperfusion, aneurismal expansion of the dissected aorta, aortic rupture or unremitting pain.
The most common presenting symptom of an acute aortic dissection is acute onset of chest or back pain, often described as a "tearing" pain.
Risk factors for aortic dissection
- History of aortic aneurysm
- History of peripheral vascular disease
The introduction of endovascular techniques to treat thoracic aortic disease allows for minimally invasive alternatives to treat aortic dissection using aortic stent grafts to cover the entry tear and restore normal aortic wall anatomy with far less morbidity and mortality risk than incurred with conventional open surgery.