A splenic artery aneurysm is a balloon-like bulge in the wall of the artery that supplies blood to the spleen, and it is the most common aneurysm found among the arteries that feed abdominal organs. In the general population, fewer than one in a hundred people have one, but the condition disproportionately affects women, with a female-to-male ratio of roughly four to one. Most splenic artery aneurysms sit quietly for years, discovered by accident when imaging is done for something else. The concern, though, is rupture, which is uncommon but can be fatal, and the condition’s relationship with pregnancy makes it a topic that deserves more attention than its low prevalence might suggest.
How Common They Are and Who Gets Them
Splenic artery aneurysms rank as the third most common true aneurysm overall, behind aortic and iliac artery aneurysms, and they account for about 60% of all visceral artery aneurysms. The prevalence in the general population sits below 1%, but autopsy studies have found rates ranging from 0.01% to 0.2%, while imaging-based studies put the number somewhat higher because CT scans catch smaller ones that would never cause symptoms. In people over 60 and those with portal hypertension (the elevated blood pressure in the liver’s venous system seen with cirrhosis), incidence climbs to around 10%.1PubMed Central. Splenic aneurysms: natural history and treatment techniques
The typical patient is a woman in her fifties. The mean age at presentation is around 52, with as many as 80% of cases occurring in people over 50.2PubMed Central. Splenic Artery Aneurysm (SAA) Rupture in Pregnancy: A Case Report of a Rare but Life-Threatening Obstetrical Complication – Section: 1. Introduction That said, the condition is not exclusive to older adults. Children can develop arterial aneurysms, though rarely in the splenic artery. A case series from the University of Michigan spanning pediatric arterial aneurysms found only two splenic artery cases among 31 aneurysms in 23 children, making it an oddity even in a rare category.3Elsevier / ScienceDirect (Journal of Vascular Surgery). Arterial aneurysms in children: Clinicopathologic classification
What Causes the Artery Wall to Weaken
A true splenic artery aneurysm involves all three layers of the artery wall stretching outward. This is different from a pseudoaneurysm, where a tear in the wall creates a pocket of blood held in place only by the outer layer or surrounding tissue. Pseudoaneurysms tend to follow trauma or pancreatitis, while true aneurysms develop gradually as the artery wall degenerates. The clinical distinction matters because pseudoaneurysms are more likely to rupture and almost always require treatment.4PubMed. Splenic artery aneurysms and pseudoaneurysms: clinical distinctions and CT appearances
At the tissue level, the process involves degeneration of the artery’s middle layer, particularly a breakdown of elastic fibers. Histological examination of ruptured aneurysms consistently shows what pathologists describe as intimomedial mucoid degeneration, essentially the structural scaffolding of the vessel dissolving and being replaced by weaker tissue.5Current Women’s Health Reviews. Sudden Rupture of Splenic Artery Aneurysm in a Pregnant Woman Resulting in the Death of the Fetus: A Case Report and Review of Literature – Section: Case Presentation Specialized staining techniques at autopsy can confirm this degeneration and help distinguish a spontaneous rupture from one caused by trauma.6PubMed Central. Fatal splenic artery aneurysm rupture at medicolegal autopsy: A case series and review of the literature
Several conditions accelerate this arterial weakening:
- Portal hypertension: Increased pressure in the portal venous system, usually from liver cirrhosis, places extra hemodynamic stress on the splenic artery. Patients awaiting liver transplant are screened for these aneurysms for this reason.7PubMed. Splenic Artery Aneurysm Management in the Cirrhotic Patient Listed for Liver Transplantation: A Systematic Review
- Connective tissue disorders: Vascular Ehlers-Danlos syndrome (vEDS), a genetic condition affecting collagen, carries a meaningful risk of splenic artery problems. In one cohort of patients with vEDS, about 5.7% developed splenic artery pathology, and aneurysms accounted for 39% of those cases. The average age at diagnosis was 37, much younger than the general population.8PubMed. Splenic artery pathology presentation, operative interventions, and outcomes in 88 patients with vascular Ehlers-Danlos syndrome
- Fibromuscular dysplasia: This condition, which causes abnormal cell growth in artery walls, is an extremely rare but documented cause. Only a handful of cases have been reported in the literature.9PubMed. Ruptured aneurysm of the splenic artery associated with fibromuscular dysplasia
- Atherosclerosis: Hardening of the arteries contributes, though whether it is a direct cause or simply coexists in the same population remains debated.
The Pregnancy Connection
Pregnancy is one of the most discussed risk factors for splenic artery aneurysm, even though the actual prevalence in women of childbearing age is very low, below 0.1%.10PubMed Central. Splenic Artery Aneurysm (SAA) Rupture in Pregnancy: A Case Report of a Rare but Life-Threatening Obstetrical Complication – Section: 1. Introduction The reason pregnancy receives so much attention is that it combines several physiological changes that stress the artery wall simultaneously: cardiac output rises, blood volume increases, portal venous pressure goes up, and hormonal changes alter the structure of arterial walls.11PubMed Central. Splenic Artery Aneurysm Case Report – Section: Discussion Hormones like estrogen and relaxin are thought to cause a degeneration of the artery’s middle layer, weakening it during a period when blood flow demands are at their highest.12Archives of Surgery and Clinical Case Reports. Splenic Artery Aneurysm in A Primigravida – Section: Discussion
Rupture during pregnancy, while rare, carries devastating consequences for both mother and fetus. The combination of the pregnant uterus compressing abdominal structures and the hemodynamic changes of the third trimester creates a period of heightened vulnerability. This is why treatment guidelines set a lower threshold for intervening in pregnant women and women planning pregnancy, as discussed in the treatment section below.
Symptoms, or the Usual Lack of Them
The frustrating reality of splenic artery aneurysms is that they rarely announce themselves. Most are found incidentally when a CT scan, MRI, or ultrasound is performed for unrelated reasons, and the rising use of cross-sectional imaging has made incidental detection increasingly common.13PubMed. Splenic artery aneurysms and pseudoaneurysms: clinical distinctions and CT appearances A systematic review and single-center study found that incidentally discovered splenic artery aneurysms are typically slow-growing with very low rupture risk.14PubMed. Incidental splenic artery aneurysms: systematic literature review and single-centre study
When a splenic artery aneurysm does rupture, the presentation can be dramatic or deceptively mild at first. Patients typically experience sudden severe pain in the upper left abdomen or upper middle abdomen, sometimes radiating to the left shoulder (a clinical sign known as Kehr’s sign, caused by blood irritating the diaphragm). Hemodynamic instability follows as blood pours into the abdominal cavity.15PubMed Central. Splenic artery aneurysm with the double-rupture phenomenon – Section: DISCUSSION
The Double-Rupture Phenomenon
One of the more treacherous aspects of splenic artery aneurysm rupture is a pattern first described in 1930 and still relevant today. In some cases, the aneurysm initially ruptures into the lesser omental sac, a small enclosed space behind the stomach. The sac temporarily contains the bleeding, and during this window the patient may feel surprisingly stable with only mild symptoms. Hours to days later, blood spills through the foramen of Winslow into the open peritoneal cavity, causing sudden hemorrhagic shock. This delay can range from 6 to 96 hours.16PubMed Central. Splenic artery aneurysm with the double-rupture phenomenon – Section: DISCUSSION The initial phase of contained hemorrhage, if recognized, provides a critical window for diagnosis and intervention. But if the initial episode of pain is dismissed, the second bleed can arrive without warning.
How They Are Found and Measured
CT angiography has become the workhorse for evaluating splenic artery aneurysms. It provides detailed three-dimensional images showing the aneurysm’s size, shape, location along the artery, internal structure, and relationship to surrounding organs. This information is essential for planning treatment, especially when an aneurysm sits in a tricky position near the hilum of the spleen or at a branch point.17PubMed Central. Computed Tomography Angiography in Diagnosis and Treatment of Splenic Artery Aneurysm
Ultrasound is often the first imaging study to pick up a splenic artery aneurysm incidentally, but it has limitations: obesity and bowel gas can obscure the view. MRI angiography is an alternative, though it is slower, more expensive, and not an option for patients with certain metallic implants. Catheter-based angiography was long considered the gold standard, but its invasive nature means it has largely been replaced by CT angiography for diagnosis, while catheter access is now reserved primarily for when endovascular treatment is planned at the same session.18PubMed Central. Computed Tomography Angiography in Diagnosis and Treatment of Splenic Artery Aneurysm
When Treatment Is Needed
Not every splenic artery aneurysm requires intervention. The current treatment thresholds reflect the balance between the low but real risk of rupture and the risks of treatment itself:
- Symptomatic aneurysms: Any aneurysm causing pain or other symptoms should be treated regardless of size.
- Larger than 2 cm: Asymptomatic aneurysms exceeding this threshold are generally treated.
- Pregnancy or planned pregnancy: Women who are pregnant or of childbearing age are treated at a lower threshold, with some guidelines recommending intervention for aneurysms larger than 1 cm.
- Between 1 and 2 cm, asymptomatic: These are monitored with imaging roughly every three years to watch for growth.19PubMed Central. Surgical management of splenic artery aneurysm – Section: Discussion
The surveillance approach for smaller aneurysms reflects the evidence that most incidental ones are slow-growing and rarely rupture. But the 2 cm cutoff is not absolute. A patient with a connective tissue disorder, rapid aneurysm growth on serial imaging, or concurrent portal hypertension may be treated earlier. Clinical judgment still drives a lot of these decisions.
Treatment Options
Treatment falls into three broad categories: endovascular procedures done through catheters, traditional open surgery, and laparoscopic surgery. The trend over the past two decades has been heavily toward endovascular approaches when the anatomy cooperates.
Endovascular Repair
Endovascular treatment can be performed using either covered stent grafts or catheter-based embolization (intentionally blocking the artery with coils or other materials). Covered stents have the advantage of sealing off the aneurysm while keeping blood flowing through the splenic artery, preserving the spleen’s blood supply. Embolization, by contrast, typically blocks the target artery segment entirely, which can lead to downstream ischemia and partial splenic infarction.20PubMed. Covered stenting and transcatheter embolization of splenic artery aneurysms in diabetic patients: A review of endovascular treatment of visceral artery aneurysms in the current era
Stent grafts work well when the splenic artery has a relatively straight course, but the vessel is notoriously tortuous. In one study, stent placement succeeded in 8 of 10 patients; in the remaining two, excessive vessel tortuosity forced a switch to coil embolization. Patients who received stent grafts had a median hospital stay of just one day and showed patent, leak-free stents on follow-up imaging.21Journal of Vascular Surgery. Feasibility of endovascular repair of splenic artery aneurysms using stent grafts – Section: Results A case report of endovascular stent graft placement for a complex anatomical variant showed the aneurysm shrinking on follow-up CT at three and a half years, with no complications.22PubMed Central. Endovascular Stent Graft Placement and Coil Embolization for Splenic Artery Aneurysm with an Anatomical Variant – Section: Case Report
A cost-effectiveness analysis modeling a population of 55-year-old women with splenic artery aneurysms found that endovascular repair provided the highest quality-adjusted life years and was more cost-effective than open surgery. Compared with conservative management (watching and waiting), endovascular repair was more effective and more expensive, but still fell within acceptable cost-per-benefit thresholds.23PubMed. Cost-effectiveness of endovascular repair, open repair, and conservative management of splenic artery aneurysms A separate Japanese cost-effectiveness study confirmed that preventive embolization for the typical patient (a 60-year-old woman) fell within acceptable willingness-to-pay thresholds.24Journal of Vascular and Interventional Radiology. Cost-Effectiveness of Preventive Transarterial Embolization for Splenic Artery Aneurysms – Section: Results
Open and Laparoscopic Surgery
Open surgery was the standard approach for decades and remains necessary for very large aneurysms, ruptured cases with hemodynamic instability, or anatomy that defeats endovascular access. The operation may involve simply tying off and removing the aneurysm, or it may require removing the spleen along with it, particularly when the aneurysm sits near the hilum where the artery enters the spleen.25PubMed Central. Laparoscopic Excision of Splenic Artery Aneurysm – Section: Discussion
Laparoscopic surgery offers a middle ground: the precision of open surgery with smaller incisions and faster recovery. Early reports described the technique’s feasibility, and it has since expanded to include even complex hilar aneurysms, sometimes combined with distal pancreatectomy when the aneurysm is intimately involved with the pancreatic tail.26PubMed. Splenic artery aneurysms: methods of laparoscopic repair In practice, the choice between open and laparoscopic approaches depends on the aneurysm’s size, location, and the urgency of the situation. Elective cases in stable patients increasingly go laparoscopic; emergency repairs still often require open access.
Why Keeping the Spleen Matters
Regardless of the treatment approach, preserving the spleen is a priority whenever anatomy allows. The spleen plays an important role in immune function, particularly in filtering bacteria from the bloodstream. Removing it leaves a person permanently vulnerable to overwhelming post-splenectomy infection, a rare but potentially fatal complication caused by encapsulated bacteria. Splenectomy also appears to carry long-term cardiovascular risks.27PubMed. Benefits and risks of splenectomy
Surgeons aim to reconstruct or bypass the aneurysmal segment when there is enough healthy artery to work with.28PubMed Central. Spleen-Preserving Surgery in Splenic Artery Aneurysm When the spleen’s blood supply is interrupted during embolization rather than surgery, the spleen often survives on collateral blood flow, though partial infarction is common. A study of endovascular embolization for splenic artery aneurysms found that about half of patients developed some degree of splenic infarction.29PubMed Central. Technical and clinical outcomes of endovascular treatment for splenic artery aneurysms – Section: RESULTS Splenectomy after embolization, however, was needed in only a small percentage of cases in trauma settings, suggesting that most spleens tolerate partial loss of blood supply.30PubMed Central. Splenic salvage and complications after splenic artery embolization for blunt abdominal trauma: the SPLEEN-IN study – Section: Results
What Happens After Treatment
Post-treatment complications depend on the method used. Endovascular embolization carries a risk of post-embolization syndrome, a cluster of symptoms including fever, pain, and malaise that occurs as the body responds to tissue ischemia. In one series, about 16% of patients experienced it.31PubMed Central. Technical and clinical outcomes of endovascular treatment for splenic artery aneurysms – Section: RESULTS These symptoms are self-limiting and managed conservatively.
Splenic infarction after embolization deserves attention. A study examining predictive factors for infarction found that it occurred in about 38% of patients, with aneurysms located closer to the spleen (distal or hilar) carrying a higher risk. Among those who developed infarction, half showed signs of splenic regeneration on follow-up imaging, while the other half progressed to splenic atrophy. The degree of residual blood flow to the spleen after the procedure was the strongest predictor of whether the spleen would recover.32PubMed Central. Predictive factors for post-embolization infarction and long-term splenic remodeling in patients undergoing splenic artery aneurysm embolization – Section: RESULTS All complications in that series resolved with conservative management, and no major complications or deaths occurred.
For stent graft patients, the key concern on follow-up is endoleak (blood leaking around or through the stent back into the aneurysm sac) and stent occlusion. Long-term imaging surveillance, typically with CT, is standard after both embolization and stenting to ensure the aneurysm stays sealed and the spleen remains adequately perfused.
Living with a Watched Aneurysm
For the many patients whose small, incidentally discovered aneurysm falls below the treatment threshold, surveillance becomes a long-term reality. This means periodic imaging (usually CT or ultrasound) to check whether the aneurysm is growing. The recommended interval for aneurysms between 1 and 2 cm is about every three years, though clinicians may shorten this if additional risk factors are present.33PubMed Central. Surgical management of splenic artery aneurysm – Section: Discussion
What the surveillance guidelines do not capture well is the psychological dimension. Research on patients living under surveillance for abdominal aortic aneurysms, a condition with a similar watch-and-wait philosophy, has shown that anxiety and depression are measurable concerns, and that patients with less education and those with a family history of aneurysms tend to experience higher levels of anxiety. Interestingly, anxiety and depression scores tended to decrease in patients who eventually underwent surgery.34PubMed Central. Evolution of quality of life, anxiety, and depression over time in patients with an abdominal aortic aneurysm approaching the surgical threshold – Section: Results While this study addressed aortic aneurysms specifically, the psychological dynamics of knowing you have a vessel that could rupture and being told to simply wait are likely similar. Patients undergoing surveillance for splenic artery aneurysms may benefit from understanding that the evidence strongly favors a conservative approach for small, asymptomatic lesions, and that the vast majority never progress to rupture.
Misconceptions Worth Correcting
One common misunderstanding is that any aneurysm is a ticking time bomb. For splenic artery aneurysms, the data show otherwise: most incidental ones grow slowly or not at all, and the overall rupture risk for unruptured, asymptomatic aneurysms is low.35PubMed. Incidental splenic artery aneurysms: systematic literature review and single-centre study The 2 cm treatment threshold exists precisely because the risk-benefit equation below that size generally favors observation over intervention.
Another misconception is that pregnancy causes splenic artery aneurysms. Pregnancy creates conditions that can promote aneurysm formation and dramatically raise the stakes if one ruptures, but having been pregnant does not guarantee you have one, and most women who have had multiple pregnancies never develop one. The prevalence in women of childbearing age remains very low.
A third area of confusion involves the distinction between true aneurysms and pseudoaneurysms. Patients sometimes hear “aneurysm” and assume the worst, not realizing that the two types have different causes, different natural histories, and different urgency levels. Pseudoaneurysms after pancreatitis or trauma are generally more dangerous and less likely to be watched, while true aneurysms found incidentally in otherwise healthy people often need nothing more than periodic imaging.