Aortic dissection is a potentially life-threatening condition that occurs when a tear in the inner lining of the aorta (usually in the chest portion of the artery) causes bleeding between the inner and outer layers of the wall of the aorta. The layers become separated (or dissected) creating a false channel for blood to flow. It is the most common emergency affecting the aorta. Symptoms include sudden, severe, sharp chest pain that spreads to the neck or down the back, sudden difficulty speaking, a weak pulse and loss of consciousness. Aortic dissections typically occur in adults aged between 60 and 70 years, with more males than females. The main cause is thought to be high blood pressure. An aortic dissection is classified depending on where it begins in the aorta and if it is acute or chronic. Acute dissections are diagnosed within 14 days after the first symptoms appear; while chronic ones are diagnosed after 14 days. This review looked at chronic type B dissections, which begin in the descending part of the aorta (the section of the artery that moves down through the chest and abdomen). Patients with this type of aortic dissection have traditionally been treated with blood pressure lowering medications, with good short-term results (annual survival in excess of 80%). They have, however, increased long-term mortality. In the long term, medical treatment alone may put some patients at risk of serious complications such as progressive aortic enlargement, poor blood flow to some organs or the extremities, and aortic rupture. Patients with these life-threatening complications require urgent treatment of the dissected aorta by open surgery or, more recently, endovascular thoracic aortic stent grafting (TEVAR). TEVAR reduces the number of early deaths compared with open surgical treatment.

For people with chronic uncomplicated aortic dissection, there is uncertainty about whether stent grafting in addition to best medical therapy improves patient outcomes. This review identified a single trial that randomised 140 patients with uncomplicated chronic type B aortic dissection to medical treatment alone or medical treatment plus stenting. The trial was methodologically sound but did not show a meaningful difference in two-year survival between the two treatment options. The number of deaths observed in the trial did not meet the number expected from registry data, so the trial was underpowered for that end point. Longer-term data from the trial are awaited. Over 20% of the patients initially randomised to the optimal medical care group 'crossed over' to receive TEVAR or open surgery because of the degree of expansion of the aorta with medical therapy alone.