Splenic Artery Aneurysm
A splenic artery aneurysm is a localized enlargement of the splenic artery, the major blood vessel that supplies the spleen. It is the most common type of visceral artery aneurysm and is often discovered incidentally on abdominal imaging. Causes include atherosclerosis, fibromuscular dysplasia, pregnancy-related changes, portal hypertension, connective tissue disorders, infection, and trauma. Most splenic artery aneurysms cause no symptoms, but rupture can be a life-threatening emergency, particularly in pregnancy. CT angiography and MR angiography are the primary tools for diagnosis and surveillance.
What is it?
The splenic artery is the largest branch of the celiac trunk, which arises from the abdominal aorta and supplies blood to the spleen, parts of the stomach, and the pancreas. A splenic artery aneurysm is a localized enlargement (typically defined as a diameter at least 1.5 times the normal size of the vessel or above certain size thresholds) of this artery. Splenic artery aneurysms are the most common type of visceral artery aneurysm, accounting for the majority of cases involving the arteries that supply abdominal organs.
Several factors contribute to the development of splenic artery aneurysms. Atherosclerosis is one of the most common contributors, particularly in older adults. Pregnancy-related changes—including hormonal effects on the artery wall and increased blood flow during pregnancy—are an important reason that splenic artery aneurysms are more common in women, especially those with multiple pregnancies. Fibromuscular dysplasia, a non-atherosclerotic disease of artery walls, can affect the splenic artery and produce characteristic findings. Portal hypertension and chronic liver disease are associated with splenic artery aneurysms, possibly because of increased flow and changes in the vessel wall. Less common contributors include connective tissue disorders (such as Marfan syndrome, Loeys-Dietz syndrome, and vascular Ehlers-Danlos syndrome), vasculitis, infection (mycotic aneurysm), trauma, pancreatitis (which can cause pseudoaneurysms—a related but distinct entity), and prior surgery or radiation.
Most splenic artery aneurysms cause no symptoms and are discovered incidentally on abdominal imaging done for other reasons. When symptoms do occur, they are often vague and may include upper abdominal or left flank discomfort, early fullness with meals, or, occasionally, referred pain to the left shoulder. Rarely, very large aneurysms may produce a pulsatile sensation in the upper abdomen.
The most serious complication is rupture, in which the wall of the aneurysm breaks open and causes major internal bleeding. Splenic artery aneurysm rupture typically presents with sudden, severe upper abdominal or left-sided pain and signs of shock and is a surgical emergency. Rupture risk is particularly elevated in pregnancy—especially in the third trimester—where rupture can be catastrophic for both mother and fetus, and in patients with portal hypertension or rapidly growing aneurysms. Smaller, stable, calcified aneurysms in older adults generally have a lower risk of rupture. Pseudoaneurysms of the splenic artery (typically following pancreatitis or trauma) carry a higher risk of rupture and are usually treated when identified.
CT angiography of the abdomen and pelvis is the primary imaging test for evaluating splenic artery aneurysms because it provides detailed three-dimensional information about size, shape, location, calcification, and surrounding structures, including the pancreas and other organs. MR angiography is a useful alternative, particularly when avoiding radiation or iodinated contrast is preferred. Ultrasound may identify some aneurysms but is often limited by overlying bowel gas. Catheter-based angiography is typically reserved for selected patients at the time of planned intervention. Imaging may also reveal coexisting aneurysms in other vascular territories.
Important to Know
Management of a splenic artery aneurysm is individualized and depends on the size, location, shape, cause, growth rate, the presence of complications, and patient-specific factors such as pregnancy or planned pregnancy. For small, asymptomatic, stable aneurysms in older patients with low rupture risk, periodic imaging surveillance and aggressive cardiovascular risk reduction are typically recommended.
Important measures include smoking cessation, control of blood pressure, statins and other lipid-lowering therapies in patients with significant atherosclerosis, treatment of diabetes when present, healthy diet, regular physical activity, weight management, and limited alcohol. While these measures may not directly shrink an aneurysm, they reduce overall cardiovascular risk and may slow progression.
Treatment is generally considered for splenic artery aneurysms that are larger than certain size thresholds (commonly around 2 centimeters, although guidelines vary), growing on follow-up imaging, causing symptoms, or that have ruptured. Treatment is also typically recommended for splenic artery aneurysms in women of childbearing age (because of pregnancy-related rupture risk), in pregnant patients (when feasible and based on individual circumstances), and in patients with high-risk features such as pseudoaneurysms, mycotic aneurysms, or connective tissue disorders. Patients with portal hypertension or who are being considered for liver transplantation also often require treatment.
Endovascular treatment is now the most common approach for elective management of many splenic artery aneurysms. Options include catheter-based coil embolization (placing small coils inside the aneurysm to block blood flow), placement of covered stents (stent grafts) across the aneurysm, and other newer endovascular devices. The choice depends on the size, location, and shape of the aneurysm and the anatomy of the splenic artery. Surgical repair—including aneurysm resection with or without splenectomy, and various reconstruction techniques—remains an important option, particularly for complex anatomy, certain aneurysm locations near the spleen, or when endovascular treatment is not feasible. Ruptured splenic artery aneurysms require emergency treatment with either endovascular or surgical management.
Care is typically coordinated by primary care clinicians, vascular surgeons, interventional radiologists, hepatologists (in patients with portal hypertension), obstetricians (in women of childbearing age), and other relevant providers. Imaging findings are interpreted alongside symptoms, examination, and the patient’s overall health.
Patients with known splenic artery aneurysms—particularly women planning pregnancy—benefit from clear discussion of the risks of rupture, the rationale for treatment, and the importance of seeking immediate care if warning signs develop. First-degree relatives of patients with familial aortic and visceral aneurysmal disease may benefit from screening in selected circumstances.
Red flag symptoms include sudden severe upper abdominal or left flank pain, referred shoulder pain with severe abdominal symptoms, lightheadedness or fainting, rapid heart rate, cool clammy skin or signs of shock, severe vomiting with abdominal pain, or any sudden severe abdominal symptoms in a known pregnancy. These warrant immediate emergency evaluation, as they may indicate rupture of the aneurysm.