The splenic artery is the most common site of an aneurysm in the splanchnic circulation, occurring at the arterial bifurcation as it enters the hilus in most cases. Pathogenesis includes factors that increase vascular stress, such as multiple pregnancies and portal hypertension. This aneurysm is often discovered incidentally, but severe and life-threatening bleeding with resultant shock may develop. Diagnosis is made by imaging studies and treatment includes various surgical techniques.
The majority of patients are asymptomatic and the diagnosis of SAA is often made incidentally. When symptoms are present, initial complaints include abdominal pain, specifically in the left upper quadrant or in the epigastric region, together with nausea and vomiting . Development of rapidly progressive hypotension and hypovolemic shock can be frequently observed in the event of the aneurysmal rupture, which can often be life-threatening and can manifest with pallor, progressive weakness and poor general condition of the patient, which necessitates rapid treatment.
Although various imaging studies may determine the presence of SAA, the general condition of the patient may significantly reduce the number of viable imaging studies and the diagnosis of may be difficult to attain during early stages. Ultrasonography is usually the initial method of choice, while an emergency CT scan can be used to determine the presence of an aneurysm through the use of contrast . If the patient is stable, regular CT or MRI of the abdomen may be performed. However, the gold standard in diagnosing SAA is angiography , which can detect the exact location and size of the aneurysm. More importantly, information obtained by this diagnostic method including size, location, and degree of rupture are vital in determining optimal treatment strategies.
Surgery is the mainstay of treating patients with SAA and indications for surgical treatment include symptomatic aneurysms and those that are > 2 cm in diameter . Women in their childbearing age and liver transplant candidates are individuals in whom asymptomatic SAA is indicated for surgical management . Various modalities exist :
In the past few decades, the use of novel imaging techniques has led to the discovery of many SAAs incidentally, as the majority of patients are asymptomatic, and they have a good prognosis when discovered in early stages. The overall risk of rupture varies between studies and ranges between 5-25% . When ruptures do occur, they can cause severe and life-threatening complications, with mortality rates reaching up to 70% . Pregnant women in their third trimester or prior to labor are at most risk in the event of SAA rupture, as mortality rates have been established to be 70% for the mother and 90-95% for the fetus , which illustrates the risk this condition may cause.
The exact cause of SAA remains to be discovered, but several factors are thought to be involved. Estrogen effects on vascular tissue, accelerated blood flow and disturbances in collagen synthesis have all been implied in the pathogenesis. Numerous conditions that exert such effects have been associated with SAA, including pregnancy and portal hypertension being the two most important, while medial fibrodysplasia, atherosclerosis, pancreatitis, collagen vascular disease and various other have been associated with this type of aneurysm . Vascular diseases, such as hypertension, and polyarteritis nodosa have been mentioned as potential factors as well .
SAAs are rare but are established to be the most common visceral aneurysms, comprising about 60% , and it is established to be the third most common aneurysm overall, with abdominal aortic and iliac being first and second, respectively . The most common site is established to be at the bifurcation as the splenic artery enters the hilum, but aneurysms can occur at any point during its course and sometimes more than one aneurysm can develop. Incidence rates of SAA range from 0.02%-10.4% in the general population , while prevalence rates range from 0.1%-2% according to certain studies . Gender predilection toward females is quite prominent, as SAA is almost four times more frequently seen in women, with multiple pregnancies being the most important risk factor. Increasing age is also deemed to be a risk factor for SAA, but patients of any age may develop this type of aneurysm .
Initial theories of SAA development included congenital defects of arterial walls, as well as atherosclerosis, as potential causes of this vascular malformation, but recent studies indicate that atherosclerosis plays a minor role. Presumably, increased local pressures within vascular compartments due to portal hypertension or multiple pregnancies cause significant amounts of stress to the vessel wall . Pathological changes in the tunica media include degeneration of collagen and elastic fibers that result in disruption of normal arterial architecture . Cells of the tunica media are replaced by a mucoid material, eventually leading to the formation of aneurysms. However, the exact pathophysiologic mechanism of SAA remains to be discovered.
Since the cause and pathogenesis of SAA have only been partially determined, current preventive strategies could be aimed at the screening of individuals who are at risk for developing this lesion, such as those with portal hypertension, pancreatitis, and pregnant women. Cause-directed prevention is currently not possible.
Splenic artery aneurysm (SAA) is one of the most frequently encountered aneurysms, as it is the most common aneurysm of the splanchnic circulation and the third most common overall, after abdominal aortic and iliac . The majority of SAAs are true aneurysms and several theories have been made regarding its pathogenesis. Having in mind the fact that it is almost four times more frequently diagnosed in women and that multiple pregnancies are established to be one of the most important risk factors, the effects of estrogen on vascular tissue is assumed to play a significant role . Additionally, portal hypertension, pancreatitis and various other conditions that increase splenic blood flow are thought to contribute as well . Atherosclerosis, on the other hand, is thought to be only partially involved. The majority of SAAs are discovered incidentally since the majority of patients are asymptomatic, but when symptomatic, it may cause bleeding that can be life-threatening. The overall risk of rupture ranges from 5-25% in different studies. More importantly, mortality rates in case of rupture are very high in pregnant women, with maternal mortality rates reaching 70%, while fetal mortality rates are over 90% , implying that SAA can be fatal for patients if not diagnosed on time. Abdominal pain, vomiting and rapid development of shock are most common findings in symptomatic SAAs. The diagnosis can be made by various imaging studies, including computed tomography (CT scan), ultrasonography, and magnetic resonance imaging (MRI), but the definite method of assessing the features of an aneurysm and determine the need for therapy is angiography . Indications for surgical treatment, which is the method of choice, includes symptomatic aneurysms, the diameter of > 2 cm, pregnancy and progressive growth of the aneurysm . Open laparotomy, laparoscopy, open surgery and percutaneous embolization are all options. Their utilization depends on various factors , including the location of the aneurysm, diameter and general condition of the patient.
Splenic artery aneurysm is a condition that describes the development of an aneurysm in the splenic artery. An aneurysm is a sac-like formation of the blood vessel wall. This part of the vessel wall is more prone to rupture and can result in bleeding that can be life-threatening. The exact cause, however, remains unknown, but in the case of splenic artery aneurysm, factors that are established to significantly increase the risk of its development include portal hypertension (increased pressure in the vessels of organs situated in the abdomen) and multiple pregnancies. Moreover, this disorder is almost four times more frequently diagnosed in women, which indicated that perhaps hormonal factors also play a role in the development of this vascular malformation. Although the majority of patients are asymptomatic and this aneurysm is often discovered incidentally, rupture of splenic artery aneurysm can occur and can be fatal. The overall risk of rupture is estimated to be between 5-25%. Women in their third trimester or prior to labor are at a very high risk of developing life-threatening complications, which is why screening for this condition may be favorable. Symptoms, when present, include the sudden appearance of abdominal pain, nausea, and vomiting. A rapid onset of decreased blood pressure and shock may be evident, which requires immediate treatment. The diagnosis can be made by various imaging techniques, such as ultrasound, computed tomography (CT scan) or magnetic resonance imaging (MRI), but a definite diagnosis can be made by angiography, which comprises insertion of contrast that will visualize all blood vessels and determine the site of the rupture. Treatment is indicated in all symptomatic patients and in those where the aneurysm exceeds 2 centimeters in diameter, with surgery being the universal method. Various surgical techniques can be used, including laparoscopy, laparotomy, open surgery, use of stents and catheterization and the choice depends on several factors, including the location of the aneurysm, its size but also the general condition of the patients. Overall, this condition can pose a life-threatening risk for patients and its identification during asymptomatic stages can significantly reduce the rate of complications.