Splanchnic Artery Aneurysms

1. Splanchnic Artery Aneurysms Katherine B. Harrington Vascular Surgery Conference May 15, 2006

2. Splanchnic Artery Aneurysms • Uncommon, but clinically important • 22% present emergently, with an overall mortality of 8.5%. • Incidence is increasing as imaging improves, but distribution is constant. • One-third will have associated nonvisceral aneurysms as well- aortic, renal, iliac, lower extremity, and cerebral.

3. Splanchnic Aneurysm Treatment • Although noninvasive imaging is improving, selective arteriography is the mainstay for planning therapy. • Surgery is still considered the gold standard especially for emergent rupture but both prophalactic and post-rupture catheterization are gaining in popularity. • Consistent long term results are lacking e.g: -Study 1: 92% early success rate, 4% mortality at 1 month, and only 1 recurrence at 4 years. vs. -Study 2: 57% early success rate, convert to open in 20%. • Catheter based interventions more appropriate for those aneurysms involving solid organs, e.g. those embedded in hepatic or pancreatic tissue with well formed collaterals.

4. Splenic Artery Aneurysms • Incidence: -Necropsy series vary between 0.098% to 10.4%. -0.78% on review of abdominal arteriographic studies. -Female to male ratio of 4:1. • Pathophysiology: -Saccular macroaneurysms secondary to acquired derangements of vessel wall: elastic fiber fragmentation, loss of smooth muscle, and internal elastic lamina disruption. -Occur most often at bifurcations. -Multiple in 20% of patients.

5. Splenic Aneurysms: Risk Factors • Fibromuscular Dysplasia: • Those with renal dysplasia are 6x more likely to have splenic aneurysm. • Portal Hypertension with Splenomeglay: • Splenic Aneurysms found in 10-30% of patients. • Often multiple aneurysms. • Multiple Pregnancies: • 40-45% of female patients in case series were grand multiparous • Thought to be secondary to both hormonal effects and increased splenic arteriovenous shunting during pregnancy. • Other: • Nearby inflammation: e.g. chronic pancreatitis -> false aneurysms. • Mycotic aneurysms from endocarditis from IVDA. • Trauma.

6. Splenic Aneurysms: Presentation • History: • 17-20% symptomatic with vague LUQ pain with occasional radiation. • 3-9.6% Rupture: Normally bleeds into lesser sac with CV collapse. • 25% of ruptures get “Double rupture phenomenon” when blood escapes lesser sac confinement. Provides window for treatment. • Ruptures can also present as GI bleeding or arteriovenous fistulas. • Exam: • -- Bruit rare. • Normally under 2cm, so rarely • palpable pulsatile mass. • Imaging/Labs: • Often found incidentally with • CT/MRI/Arteriography. • 70% will have curvilinear, signet • ring calcification on Xray. • MMP-9 for monitoring progression.

7. Splenic Aneurysm: Treatment Indications • Indications for Treatment: • Symptomatic Aneurysms • Aneurysms > 2 cm. • OLT patients: mortality post rupture >50%. • Pregnant patients or those who want to conceive: • Maternal mortality post rupture –70%, fetus- 75%. • Not associated with increased risk for rupture: • Calcifications • Age >60 • Hypertension.

8. Splenic Aneurysms: Treatment Options • Aneurysmectomy, Aneursymorraphy, Simple ligation-exclusion without arterial reconstruction. Restoration of splenic artery continuity is rarely indicated. • Endovascular Coiling-still with unsure failure rates, risk of splenic infarction. • Stent Grafting- rare when splenic flow is needed for other theraputic reason like mesocaval shunting.

9. Splenic Aneurysm: Treatment • Proximal Aneurysms: • Excise Gastrohepatic ligament. • Expose through lesser sac. • Ligate entering and exiting vessels. • Those not embedded in pancreatic tissue are excised. • Mid-Splenic Aneurysms: • Generally associated with pancreatitis- generally false aneurysms. • Clamp proximal splenic artery. • Ligate arteries with prolene from within aneurysmal sac to reduce infection. • Placement of external drains in associated psuedocysts. • May need distal pancreatectomy. • Peri-Hilar: • Conventionally treated by splenectomy. • Now simple suture obliteration, aneurysmorraphy, or excision recommended.

10. Hepatic Artery Aneurysms • Incidence: • 20% of splanchnic aneurysms. • 1/3 associated with splenic aneurysms. • Male: Female 2:1. • Most common in patients in their 50s. • Normally solitary • Average >3.5 cm. Those >2cm tend to be saccular. • 80% Extrahepatic, 20% intrahepatic. • Common hepatic: 63% • Right hepatic: 28% • Left Hepatic 5% • Right and Left hepatic: 4%.

11. Hepatic Artery Aneurysms • Etiology: • Medial degeneration- 24%. • False aneurysms secondary to trauma- 22% • Infectious (IVDA)- 10% • Oral amphetamine use- ? • Periarterial inflammation, e.g. cholecystitis or pancreatitis- rare.

12. Hepatic Aneurysms: Presentation • Most likely asymptomatic. • Can present as RUQ or epigastric pain +/- radiation to the back not associated with meals. • Manifest as extrahepatic bile duct obstruction when large aneurysms compress biliary tree. • Pulsatile masses and bruits rare. • Rupture risk ~20-44%. Mortality > 35%. • Rupture: into hepatobiliary tract and peritoneal cavity with equal frequency. • Rupture into bile ducts produces hematobilia- colic pain, massive GI bleeding with hematemesis, jaundice, and fevers are common. More common with traumatic intrahepatic false aneurysms. • Rupture into peritoneal cavity produced acute abdomen, CV colapse. More likely in PAN associated aneurysms.

13. Hepatic Aneurysms: Treatment • Common Hepatic Artery: • Extensive collaterals allow aneurysmectomy or exclusion without reconstruction. • However, 5 minute occlusion trial recommended to confirm flow to prevent necrosis. • Those with already existing parenchymal disease may need reconstruction.

14. Hepatic Aneurysms: Treatment • Proper Hepatic Artery and Extrahepatic branches: • Requires revascularization. • Subcostal or vertical midline incision. • Care should be taken to avoid common bile duct injury near the proximal hepatic artery near the gastroduodenal artery and pancreaticoduodenal artery.

15. Hepatic Aneurysm: Repair options • Aneurysmorrhaphy with or without vein patch closure, especially for traumatic false aneurysms. • Resection and reconstruction for fusiform or saccular with interpostion grafts using autogenous saphenous vein. Use spatulation of the artery and vein graft to produce ovoid anastomoses. • Aortohepatic bypass when interpostion not possible: • Extended Kocher manuver, medial viseral rotation. • Vein graft from aorta behind duodenum to porta hepatis. • Spatulated vein to artery with end-to-end anastomosis. • Liver parenchymal resection for intrahepatic aneurysms nonamenable to resection. • Endovascular coiling especially for traumatic- but with 42% recanulization reported.

16. Superior Mesenteric Artery Aneurysms • 5.5% of all splanchnic aneurysms. • Affects men and women equally. • Affects the first 5cm of the SMA. • Most often infectious in etiology: Nonhemolytic Strep- related to Left sided endocarditis. • Dissecting aneurysms are rare, but more common than in other visceral aneurysms. • Trauma- rare cause.

17. SMA Aneurysm: Presentation • Most are symptomatic • Intermittent upper abdominal pain progressing to constant epigastric pain. • Half of patients have a tender pulsatile mass that is not rigidly fixed. • Dissection or propagation can cause intestinal angina. • 40% Rupture rate.

18. SMA Aneurysm: Treatment • Aneursymorrhaphy or simple ligation without reconstruction is acceptible, but try temporary occlusion of SMA with assesment of bowel viability. • Aneursymectomy hazardous secondary to surrounding SMV and pancreas. • Distal lesions through transmesenteric route. Proximal lesions visualized through retroperitoneal. • Interpostition graft or aortomesenteric bypass after exclusion is rarely accomplished/done. • Transcatherter occulsion used, but stent-grafts generally not favored secondary to high infectious etiology percentage.

19. Celiac Artery Aneurysms • Equal sex predilection. 50’s. • Mostly medial degeneration related. Trauma and infection rare. • Most are asymptomatic. • Bruits heard frequently, and palpable puslatile mass in 30%. • Risk of rupture 13%. Normally intraperitoneal.

20. Celiac Aneurysms: Treatment • Aneursymectomy with aortoceliac bypass with graft originating from supraceliac aorta, or aneurysmectomy with primary reanastomosis. • OR celiac axis ligation. Do not use with liver dx. • Abdominal route, medial visceral rotation, transection of crus and median arcuate ligament to expose celiac. If celiac is particularly large may need a thoracoabdominal approach.

21. Gastric and Gastroepiploic Aneurysms • Likely etiology medial degeneration. • Often solitary • Gastric artery aneurysms are 10x more common than gastroepiploic. • Men:Women 3:1. 50s and 60s. • Over 90% present as ruptures with 70% with serious GI bleeding. Very few admit to preceding symptomatology.

22. Gastric and Gastroepiploic Aneurysms- Treatment • Treatment directed at stopping the hemorrhage- approximately 70% mortality post-rupture. • Ligation with or without excision of aneurysm is appropriate for extraintestinal lesions. • Intramural aneurysms and those bleeding into the GI tract should be excised with the portions of associated gastric tissue.

23. Jejunal, Ileal, and Colic Aneurysms

24. Jejunal, Ileal, and Colic Aneurysms • Pathogenesis poorly understood. • Equal sex distribution. 60s. • Most are solitary, mms to 1cm. • Multiple lesions seen with immunologic injury, septic emboli, or necrotizing vasculitides. • Rarely symptomatic. • Jejunal rupture rare, colic rupture more common. • 20% rupture mortality.

25. Jejunal, Ileal, and Colic Aneurysms:Treatment • Arterial ligation, aneurysmectomy, and resection of affected bowel if blood supply is compromised.

26. Gastroduodenal, Pancreaticoduodenal, and Pancreatic Aneurysms • Gastroduodenal aneurysms are 1.5% of splanchnic aneurysms and pancreaticoduodenal and pancreatic are 2%. • Men:Female is 4:1. • Etiology: Periarterial inflammation, actual vascular necrosis, and erosion by expanding pancreatic psuedocysts. False aneurysms more common. • 60% present as rupture, with a 49% mortality. • Most are symptomatic with epigastric pain radiating to back, because most are pancreatitis related. • 75% tend to have GI bleeding into stomach or duodenum.

27. Gastroduodenal, Pancreaticoduodenal, and Pancreatic Aneurysms • Treatment: Pancreaticoduodenal and pancreatic artery aneurysms are more difficult to treat secondary to their small size and being embedded in the pancreas. Intraoperative arteriography is useful. • Suture ligature of entering and exiting vessels without extra-aneurysmal dissection is appropriate. • Those involving pancreatic tissue should place appropriate drains and/or resection pancreatic tissue as needed. • Transcatheter embolization has been described, but may only serve as a temporizing step. • Stent-grafting of the SMA which occludes the pancreaticoduodenal has also been described.