Aortic dissection

Aortic dissection (AD) occurs when an injury to the innermost layer of the aorta allows blood to flow between the layers of the aortic wall, forcing the layers apart. In most cases, this is associated with a sudden onset of severe chest or back pain, often described as 'tearing' in character. Also, vomiting, sweating, and lightheadedness may occur. Other symptoms may result from decreased blood supply to other organs, such as stroke or mesenteric ischemia. Aortic dissection can quickly lead to death from not enough blood flow to the heart or complete rupture of the aorta.CT with contrast demonstrating aneurysmal dilation and a dissection of the ascending aorta (type A Stanford)Chest CT with descending (type B Stanford) aortic dissection (red circle)Type A dissection with pericardial effusion as a result.Aortic dissection with an intramural hematoma as seen on TEEType A aortic dissectionType A aortic dissectionDissection of both the thoracic and abdominal aortaDissection of both the thoracic and abdominal aorta Aortic dissection (AD) occurs when an injury to the innermost layer of the aorta allows blood to flow between the layers of the aortic wall, forcing the layers apart. In most cases, this is associated with a sudden onset of severe chest or back pain, often described as 'tearing' in character. Also, vomiting, sweating, and lightheadedness may occur. Other symptoms may result from decreased blood supply to other organs, such as stroke or mesenteric ischemia. Aortic dissection can quickly lead to death from not enough blood flow to the heart or complete rupture of the aorta. AD is more common in those with a history of high blood pressure, a number of connective tissue diseases that affect blood vessel wall strength including Marfan syndrome and Ehlers Danlos syndrome, a bicuspid aortic valve, and previous heart surgery. Major trauma, smoking, cocaine use, pregnancy, a thoracic aortic aneurysm, inflammation of arteries, and abnormal lipid levels are also associated with an increased risk. The diagnosis is suspected based on symptoms with medical imaging, such as computed tomography, magnetic resonance imaging, or ultrasound used to confirm and further evaluate the dissection. The two main types are Stanford type A, which involves the first part of the aorta, and type B, which does not. Prevention is by blood pressure control and not smoking. Management of AD depends on the part of the aorta involved. Dissections that involve the first part of the aorta usually require surgery. Surgery may be done either by an opening in the chest or from inside the blood vessel. Dissections that involve the second part of the aorta can typically be treated with medications that lower blood pressure and heart rate, unless there are complications. AD is relatively rare, occurring at an estimated rate of three per 100,000 people per year. It is more common in males than females. The typical age at diagnosis is 63, with about 10% of cases occurring before the age of 40. Without treatment, about half of people with Stanford type A dissections die within three days and about 10% of people with Stanford type B dissections die within one month. The first case of AD was described in the examination of King George II of Great Britain following his death in 1760. Surgery for AD was introduced in the 1950s by Michael E. DeBakey. About 96% of individuals with AD present with severe pain that had a sudden onset. The pain may be described as a tearing, stabbing, or sharp sensation. About 17% of individuals feel the pain migrate as the dissection extends down the aorta. The location of pain is associated with the location of the dissection. Anterior chest pain is associated with dissections involving the ascending aorta, while interscapular back pain is associated with descending aortic dissections. If the pain is pleuritic in nature, it may suggest acute pericarditis caused by bleeding into the sac surrounding the heart. This is a particularly dangerous eventuality, suggesting that acute pericardial tamponade may be imminent. Pericardial tamponade is the most common cause of death from AD. While the pain may be confused with that of a heart attack, AD is usually not associated with the other suggestive signs, such as heart failure and ECG changes. Less common symptoms that may be seen in the setting of AD include congestive heart failure (7%), fainting (9%), stroke (6%), ischemic peripheral neuropathy, paraplegia, and cardiac arrest. If the individual fainted, about half the time it is due to bleeding into the pericardium, leading to pericardial tamponade. Neurological complications of aortic dissection, such as stroke and paralysis, are due to the involvement of one or more arteries supplying portions of the central nervous system. If the AD involves the abdominal aorta, compromise of one or both renal arteries occurs in 5–8% of cases, while ischemia of the intestines occurs about 3% of the time.