Splenic artery aneurysm

Ishimaru H, Murakami T, Matsuoka Y, et al. (2004) N-butyl 2-cyanoacrylate injection via pancreatic collaterals to occlude splenic artery distal to large splenic aneurysm after proximal coil embolization. AJR Am J Roentgenol 182 213-215... 

Fig. 3.10a-d. A large splenic artery false aneurysm is demonstrated near tbe bilum of tbe spleen (a). Tbe 6-F RDC catheter is advanced into tbe orifice of the splenic artery and a microcatheter is passed to the site of injury in the distal splenic artery (b). The microcatheter is advanced distally beyond the site of the communication with the false aneurysm. Micronester coils are placed distal and proximal to the origin of the false aneurysm (c and d) and the final angiogram demonstrates occlusion of the lower pole of the spleen with preservation of the upper pole... 

Death due to rupture of a splenic artery aneurysm occurred during dobutamine -I-atropine stress echocardiography in a 55-year-old man [91 ]. 

Klaas JP, Diller CL, Harmon TV, Skarda DE. Death caused by splenic artery aneurysm rupture during dobuta-mine-atropine stress echocardiography case report and literature review. Echocardiography 2009 26(1) 93-5. 

Although atherosclerosis has been implicated, there is debate as to whether it is the cause or the result of aneurysm formation. The heavy calcification seen in splenic artery aneurysms maybe due to altered hemodynamics. For example, splenic artery aneurysms can be seen with portal hypertension (Fig. 8.3). Saccular or berry aneurysms associated with hypertension and atherosclerosis arise at... 

Fig. 8.3. a Celiac angiogram in a patient with portal hypertension demonstrating a distal splenic artery aneurysm, b Celiac angiogram from another patient with multiple splenic aneurysms associated with portal hypertension who has undergone liver transplantation. Note the large hepatic pseudoaneurysm just medial to the upper pole of the right kidney, c Selective common hepatic artery injection in the patient from b... 

The splenic artery arises from the celiac axis and is often tortuous. Therefore, glide wires and hydrophilic catheters are helpful in gaining peripheral access to this vessel. It has a long course from the aorta to the splenic hilum, making it one of the most amenable arteries for stent graft placement. It supplies branches to the body and tail of the pancreas. If necessary, complete occlusion of the main splenic artery distal and proximal to the aneurysm neck can be performed. If the artery is completely thrombosed, collaterals can be parasitized resulting in a splenic remnant or even hypertrophy of splenules after an embolization. 

Considered the most common, the splenic artery aneurysm has been reported to comprise approximately 60% of all VAAs [1,2]. This entity affects females four times as often as males. Typically seen in multiparous women, this aneurysm has a high propensity to rupture in the third trimester of pregnancy [29]. Asymptomatic aneurysms can often be seen as round calcified masses in the left upper quadrant on plain films and computed tomography. This type of aneurysm has been associated with portal hypertension. Many causes exist and include pancreatitis, portal hypertension, endocarditis, cystic medial necrosis, iatrogenic, and collagen vascular diseases such as Ehlers-Danlos. 

Complications of the embolization procedure include those of diagnostic angiography with the addition of aneurysm rupture, nontarget embolization, splenic infarction, abscess formation, and rarely sepsis (Fig. 8.5). Total splenic infarction can occur, which puts the patient at an increased risk of infection with encapsulated bacteria such as pneumococcus. Older literature suggests that bland splenic artery aneurysms rupture at a rate of approximately 2% [30]. However, in pregnant patients, rupture occurs in nearly every case with mortality rates for mother and fetus 70% and 95% respectively [31]. Obviously, any aneurysm in the pregnant female should be addressed since over 95% will rupture if left untreated [30, 32]. 

After a retrospective review of ten years of experience, Carr et al. found that 42% of their cases of VAAs presented with rupture [33]. Half of all the VAAs were splenic artery aneurysms. Of the splenic artery aneurysms that were observed, 33% went on to rupture. This is much higher than the previously reported 2% rupture rate and reflects the fact that... 

Rupture is a rare risk of these aneurysms. However, pregnant women are more prone to rupture just as with splenic artery aneurysms. Schorn et al. provided a succinct review of the literature regarding the... 

Shanley CJ, Shah NL, Messina LM (1996) Common splanch-nic artery aneurysms splenic, hepatic, and celiac. Ann Vase Surg 10 315-322... 

Angelakis EJ et al. (1993) Splenic artery aneurysm rupture during pregnancy. Obstet Gynecol Surv 48 145-148... 

Stanley JC, Fry WJ (1974) Pathogenesis and clinical significance of splenic artery aneurysms. Surgery 76 898-909... 

Barrett JM, Caldwell BH (1981) Association of portal hypertension and ruptured splenic artery aneurysm in pregnancy. Obstet Gynecol 57 255-257... 

Macfarlane JR, Thorbjarnarson B (1966) Rupture of splenic artery aneurysm during pregnancy. Am J Obstet Gynecol 95 1025-1037... 

Marx M et al. (2002) Treatment of a splenic artery aneurysm with use of a stent-graft. J Vase Interv Radiol 13 1282... 

Yoon HK et al. (2001) Stent-graft repair of a splenic artery aneurysm. Cardiovasc Intervent Radiol 24 200-203... 

Dave SP et al. (2000) Splenic artery aneurysm in the 1990s. Ann Vase Surg 14 223-229... 

Visceral aneurysms are uncommon and most frequently involve the splenic artery. They may also arise from the pancreaticoduodenal branches of either the GDA or SMA and the left gastric artery (Fig. 14.3). Although an underlying cause may not he demonstrated, many of these are associated with acute or chronic pancreatitis or are secondary to atheromatous disease. Atheromatous stenosis of the coeliac axis or compression of the coeliac axis by the median arcuate ligament of the diaphragm results in hypertrophy of the pancreaticoduodenal arteries and is associated with aneurysm formation. 

Percutaneous splenoportography has lost its importance. Should a direct procedure be indicated, laparoscopic splenoportography is a possible alternative. Recently, a new technique has been described. (134) The percutaneous splenic puncture is performed using a thin needle under screen control, with the needle directed at the splenic hilus. The pressure of the splenic pulp can be measured directly in order to estimate the portal vein pressure. Contrast medium is injected manually or by a special device. From this depot in the red pulp, the splenic vein, the portal vein and the intrahepatic branches of the portal vein are contrasted within a few seconds, (s. fig. 8.12) Complications resulting from percutaneous splenoportography include afterbleeding from the spleen, bilateral rupture of the spleen, arterial aneurysms and a.v. shunts — these complications are serious in nature, but rare. Contraindications for the procedure should be carefully observed, (s. tab. 8.6)... 

There is one further indication for thrombin occlusion of pancreatitis associated visceral aneurysms. Where the portal vein has occluded as a complication and the patient has a proximal splenic or gastroduodenal aneurysm, the proximal and distal coil embolization of which could compromise the hepatic arterial supply to the liver causing liver infarction, thrombin injection maybe a safer technique [29]. 

Highly important lesions are usually defined as lesions that require surgical treatment, medical intervention, and/or further investigation during that patient care visit. Examples include indeterminate solid organ masses, previously unknown abdominal aortic aneurysms 3 cm or larger, aneurysms of the splenic or renal arteries, indeterminate chest nodule, adenopathy, and pancreatic masses. 

Results of transcatheter embolization of mesenteric aneurysms appear favorable in the literature, and technical success has been reported to range from 75% to 100% [1,3,15,18,19,24-27,33,35-42]. However, many of these studies are not only retrospective and small, but the mesenteric VAAs are often lumped in with splenic and hepatic artery aneurysms, making it difficult to isolate effective treatment rates for SMA, IMA, and GDA aneurysms independently. The anatomy and location of the lesion will often dictate the success of embolization. Furthermore, some case series report the use of different methods, such as percutaneous thrombin or coil injection versus transcatheter embolization. 

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