(See also Overview of Aortic Aneurysms and Aortic Dissection. Overview of Aortic Aneurysms and Aortic Dissection The aorta, which is about 1 inch (2.5 centimeters) in diameter, is the largest artery of the body. It receives oxygen-rich blood from the left ventricle of the heart and distributes it to all... read more )
The aorta is the largest artery of the body. It receives oxygen-rich blood from the heart and distributes it to the body through smaller arteries that branch off of it. Aneurysms may occur in any major branch of the aorta. Such aneurysms are much less common than abdominal aortic aneurysms Abdominal Aortic Aneurysms Abdominal aortic aneurysms are bulges (dilations) in the wall of the aorta in the part that passes through the abdomen (abdominal aorta). Abdominal aortic aneurysms typically slowly expand and... read more 
or thoracic aortic aneurysms Thoracic Aortic Aneurysms Thoracic aortic aneurysms are bulges (dilations) in the wall of the aorta in the part that passes through the chest (thorax). Thoracic aortic aneurysms may not cause symptoms, or they may cause... read more 
.
Risk factors for aneurysms include
Cigarette smoking
Older age
Infection in tissues near an artery can cause an infected aneurysm (mycotic aneurysm). Autoimmune diseases Autoimmune Disorders An autoimmune disorder is a malfunction of the body's immune system that causes the body to attack its own tissues. What triggers an autoimmune disorder is not known. Symptoms vary depending... read more can cause inflammation in different arteries, leading to weakening of the arterial wall, and formation of aneurysms (inflammatory aneurysm).
Subclavian artery aneurysms
Aneurysms in the subclavian artery (located in the upper part of the chest under the collarbone) sometimes occur in people with an extra rib located in the neck area (cervical rib) or those with thoracic outlet syndrome Thoracic Outlet Syndromes (TOS) Thoracic outlet syndromes are a group of disorders caused by pressure on nerves, arteries, or large veins as they pass between the neck and chest. When pressure is put on the nerves, pain and... read more 
.
Aneurysms in the arteries of the abdominal organs
Aneurysms in the arteries that deliver blood to the digestive tract (splanchnic arteries) are uncommon. However, aneurysms may occur in arteries that supply blood to other organs, including the
Spleen (splenic artery)
Liver (hepatic artery)
Intestine (superior mesenteric artery)
Kidneys (renal arteries)
Splenic artery aneurysms occur in more women than men. Causes include abnormal growth of muscle in the artery's wall (fibromuscular dysplasia Fibromuscular Dysplasia Fibromuscular dysplasia is abnormal thickening of the walls of arteries that is not related to atherosclerosis or inflammation but that causes artery narrowing or blockage. Fibromuscular dysplasia... read more ), high blood pressure in the blood vessels connected to the liver (portal hypertension Portal Hypertension Portal hypertension is abnormally high blood pressure in the portal vein (the large vein that brings blood from the intestine to the liver) and its branches. Cirrhosis (scarring that distorts... read more ), multiple pregnancies (such as with twins or triplets), penetrating abdominal injury (stab wound) or blunt abdominal trauma (such as from a motor vehicle crash), inflammation of the pancreas Overview of Pancreatitis Pancreatitis is inflammation of the pancreas. The pancreas is a leaf-shaped organ about 5 inches (about 13 centimeters) long. It is surrounded by the lower edge of the stomach and the first... read more (pancreatitis), and infection.
Hepatic artery aneurysms occur in more men than women. They may result from previous abdominal injury, use of illicit intravenous drugs (such as heroin), damage to the wall of the artery, or inflammation of tissues around the artery.
Superior mesenteric artery aneurysms are relatively uncommon among aneurysms in the arteries that go to the abdominal organs. They may result from infections, atherosclerosis Atherosclerosis Atherosclerosis is a condition in which patchy deposits of fatty material (atheromas or atherosclerotic plaques) develop in the walls of medium-sized and large arteries, leading to reduced or... read more 
, and other disorders that weaken the arterial wall.
Renal artery aneurysms may dissect Aortic Dissection An aortic dissection is an often fatal disorder in which the inner layer (lining) of the aortic wall tears and separates from the middle layer of the aortic wall. Most aortic dissections occur... read more (the layers of the artery separate) or rupture, causing sudden blockage (occlusion) of blood flow to the kidneys and kidney failure Overview of Kidney Failure Kidney failure is the inability of the kidneys to adequately filter metabolic waste products from the blood. Kidney failure has many possible causes. Some lead to a rapid decline in kidney function... read more .
Symptoms of Aortic Branch Aneurysms
Symptoms of aortic branch aneurysms vary depending on the organ that is deprived of blood. Regardless of location, infected or inflammatory aneurysms may cause pain in the area near the affected artery and symptoms of infection such as fever, weight loss, and a general feeling of illness. Furthermore, rupture of any type of aneurysm can cause rapid blood loss, pain at the site of the aneurysm, low blood pressure, and even death.
Subclavian aneurysms can cause shoulder or arm pain, a pulsating sensation, blood clots or swelling in nearby veins (due to pressure on the veins), transient ischemic attacks Transient Ischemic Attacks (TIAs) A transient ischemic attack (TIA) is a disturbance in brain function that typically lasts less than 1 hour and results from a temporary blockage of the brain’s blood supply. The cause and symptoms... read more , stroke Overview of Stroke A stroke occurs when an artery to the brain becomes blocked or ruptures, resulting in death of an area of brain tissue due to loss of its blood supply (cerebral infarction). Symptoms occur suddenly... read more , or hoarseness (due to compression of the recurrent laryngeal nerve), or impaired nerve function (due to compression of the recurrent laryngeal nerve or brachial plexus).
Most aneurysms in the abdominal aortic branches do not cause any symptoms unless they rupture.
Rarely, people with splenic artery aneurysms will have abdominal pain, nausea, and vomiting.
People with hepatic artery aneurysms will have abdominal pain or yellowing of the skin and whites of the eyes (jaundice) if the aneurysm compresses the tubes that transport bile from the gallbladder to the intestine (the biliary tract).
People with superior mesenteric artery aneurysms will have abdominal pain and bloody diarrhea (ischemic colitis) Ischemic Colitis Ischemic colitis is injury of the large intestine that results from an interruption of blood flow. Abdominal pain and bloody stools are common. Computed tomography is usually done, and colonoscopy... read more 
.
People with renal artery aneurysms will have high blood pressure, abdominal or flank pain, or blood in the urine.
Diagnosis of Aortic Branch Aneurysms
Ultrasonography or computed tomography (CT)
Sometimes aneurysms that are not causing symptoms are discovered when an x-ray or another imaging test is done for another reason. However, most aortic branch aneurysms are not diagnosed before they rupture.
Ultrasonography Ultrasonography Ultrasonography uses high-frequency sound (ultrasound) waves to produce images of internal organs and other tissues. A device called a transducer converts electrical current into sound waves... read more 
or CT Computed Tomography (CT) In computed tomography (CT), which used to be called computed axial tomography (CAT), an x-ray source and x-ray detector rotate around a person. In modern scanners, the x-ray detector usually... read more 
is typically used to detect or confirm aortic branch aneurysms. Angiography Angiography In angiography, x-rays are used to produce detailed images of blood vessels. It is sometimes called conventional angiography to distinguish it from computed tomography (CT) angiography and magnetic... read more can also be used when a person has symptoms that may be caused by an aneurysm.
Treatment of Aortic Branch Aneurysms
Surgical repair of the aneurysm
Often endovascular stent graft repair
Treatment is surgical repair of the aneurysm in which an artificial artery made of synthetic material (graft) is placed inside the aneurysm. The old arterial wall (aneurysm) is wrapped around the new graft.
Often, doctors do endovascular stent graft repair, which does not require surgery on the abdomen. To do an endovascular stent graft repair, doctors thread a long, thin wire through the large artery in the groin (femoral artery) and up to the aneurysm. Then they slide the stent graft, which is a thin tube like a collapsible straw, over the wire and inside the aneurysm. Then the stent graft is opened, forming a stable channel for blood flow.
The decision to repair aneurysms that are not causing symptoms is based on the
Risk of rupture
Extent of the aneurysm
Location of the aneurysm
Risks caused by other conditions the person may have
For splanchnic aneurysms, risk of rupture and death is high, particularly for women of childbearing age. The risk of rupture is also high for people with hepatic aneurysms. Therefore, splanchnic and hepatic aneurysms are usually repaired even if they are not causing symptoms.
Surgery for subclavian artery aneurysms may involve removal of a cervical rib (if present) from the upper chest before repair and replacement.
Treatment of infected (mycotic) aneurysms is antibiotic therapy appropriate for the specific infectious organism. Generally, these aneurysms must also be surgically repaired once the infection has been treated.
