A calcified splenic artery aneurysm (SAA) is an abnormal bulge that forms in the wall of the artery responsible for supplying blood to the spleen. The term “calcified” indicates that calcium deposits have hardened portions of the aneurysm wall. This hardening is often associated with a chronic and relatively stable condition, which helps medical professionals assess the condition’s stability and manage its risk.
Anatomy and Definition of the Condition
The splenic artery is the longest and most tortuous blood vessel originating from the celiac trunk, a major branch off the aorta in the upper abdomen. It follows a winding path along the pancreas before reaching the spleen, which filters blood and supports the immune system. SAAs are the most frequently encountered type of visceral artery aneurysm, accounting for approximately 60% of all cases affecting abdominal organs.
The aneurysm forms when the structural integrity of the artery wall weakens, allowing blood pressure to push the vessel outward, creating a balloon-like sac. These true aneurysms involve all three layers of the artery wall, unlike pseudoaneurysms. In a calcified SAA, the calcium deposits act like an internal shell, often referred to as “eggshell” calcification, suggesting the enlargement has been slow-growing.
The calcification is a result of the body depositing calcium into the damaged arterial tissue. This hardening provides structural support to the weakened wall. SAAs are often found in the middle or distal third of the artery, closer to the spleen, and are typically saccular in shape.
Factors Driving Aneurysm Formation
The underlying cause of a splenic artery aneurysm is a weakening of the arterial wall, accelerated by several physiological conditions. Portal hypertension, often due to advanced liver disease like cirrhosis, is a major factor. This condition causes high blood pressure in the portal vein system, increasing stress on the vessel wall due to elevated blood flow.
Conditions affecting the circulatory system, such as systemic hypertension and atherosclerosis (plaque buildup), also compromise the artery’s structural integrity. Hypertension increases mechanical stress on the wall, while atherosclerosis leads to degenerative changes in the tissue. These factors make the splenic artery susceptible to localized wall failure and bulging.
The condition is four times more common in females than in males, with multiple pregnancies being a documented risk factor. Hormonal changes during pregnancy, specifically increased estrogen and progesterone, weaken the connective tissue within the artery walls. The significant increase in circulating blood volume and cardiac output also places greater strain on the artery, promoting aneurysm development.
Clinical Detection and Assessment
Calcified splenic artery aneurysms are most commonly discovered incidentally when a patient undergoes imaging for an unrelated abdominal issue. Because most SAAs are small and asymptomatic, they are often found during computed tomography (CT) scans, magnetic resonance imaging (MRI), or ultrasound examinations. The characteristic appearance on imaging is a curvilinear or ring-shaped calcification in the left upper quadrant of the abdomen.
The presence of calcification is correlated with a lower immediate risk of rupture compared to non-calcified aneurysms or pseudoaneurysms. Medical professionals use imaging to precisely measure the aneurysm’s size and monitor for rapid growth, which indicates rupture risk. CT angiography provides the most detailed view, allowing accurate measurement of the diameter and assessment of the wall characteristics.
The size threshold for intervention is important, as the risk of life-threatening rupture increases with the aneurysm’s diameter. Although the condition is typically asymptomatic, rupture is a rare but serious event causing sudden, severe abdominal pain and internal bleeding. The diagnostic process focuses on quantifying rupture risk based on size, growth rate, and the structural stability suggested by the calcification.
Monitoring and Treatment Strategies
The management of a calcified splenic artery aneurysm depends on its size, symptoms, and the patient’s overall health profile. For smaller, asymptomatic calcified aneurysms, active surveillance, or “watchful waiting,” is common. This involves periodic follow-up imaging to monitor for changes, as extensive calcification suggests stability and a lower likelihood of expansion.
Intervention is required when the aneurysm reaches a specific size, typically exceeding 2 centimeters, or if the patient is symptomatic, such as experiencing abdominal pain. Treatment is also necessary if the aneurysm shows rapid enlargement or if the patient is a woman of childbearing age planning a pregnancy. The goal of treatment is to eliminate blood flow into the weakened sac to prevent rupture.
The most common intervention is an endovascular approach, a minimally invasive procedure where a catheter is guided through an artery to the aneurysm site. Materials like metal coils or liquid agents are deployed to embolize, or clot off, the aneurysm sac, effectively excluding it from circulation. Open surgical repair, which involves physically excising the aneurysm, may be necessary for large or complex cases or if the endovascular technique is not feasible.