DOI: 10.1148/rg.266055732
RadioGraphics 2006;26:1687-1704
© RSNA, 2006
Visceral and Renal Artery Aneurysms: A Pictorial Essay on Endovascular Therapy1
John L. Nosher, MD,
Jerry Chung, MD,
Lucy S. Brevetti, MD,
Alan M. Graham, MD and
Randall L. Siegel, MD
1 From the Department of Radiology, UMDNJ-Robert Wood Johnson Medical School, Medical Education Building, Rm 404, PO Box 19, New Brunswick, NJ 08903-0019. Received December 15, 2005; revision requested April 13, 2006 and received May 25; accepted June 13. All authors have no financial relationships to disclose.
Address correspondence to J.L.N. (e-mail: nosher{at}umdnj.edu).
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Abstract
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Visceral artery aneurysms (VAAs), which were once considered uncommon, are now being diagnosed with increasing frequency, a fact that reflects the routine use of computed tomography (CT), magnetic resonance imaging, and ultrasonography. Diagnostic radiology plays a major role in the detection and characterization of VAAs. Cross-sectional imaging can help exclude aneurysm rupture, which requires emergent treatment. CT angiography or catheter angiography can clearly depict the aneurysm and help identify other aortic, visceral, or peripheral aneurysms. Most important, radiologic examination can help determine the adequacy of the collateral blood supply to the vascular bed distal to the aneurysm, information that is essential prior to the initiation of endovascular treatment. Advances in endovascular therapy have allowed interventional radiologists to contribute to the management of VAAs. Coil embolization or covered stent placement can now be used to treat patients with aneurysms whose size or location would make a surgical approach problematic, as well as patients in whom surgery is considered to pose considerable risk.
© RSNA, 2006
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LEARNING OBJECTIVES
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After reading this article and taking the test, the reader will be able to:
- Describe the frequency distribution and etiology of visceral artery aneurysms.
- List the principles of endovascular exclusion of aneurysms from the arterial circulation.
- Discuss the application of these principles to specific visceral artery aneurysms.
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Introduction
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Visceral artery aneurysms (VAAs) are those intra-abdominal aneurysms that affect the celiac artery, the superior and inferior mesenteric arteries, and the renal arteries and their branches. 
VAAs involve the splenic artery in 60%–80% of cases, the hepatic artery in 20%, the superior mesenteric artery (SMA) in 5.5%, the celiac artery in 4%, the gastric and gastroepiploic artery in 4%, the gastroduodenal artery and pancreatic branches in 6%, the jejunal and ileocolic arteries in 3%, and the inferior mesenteric artery in less than 1% (1). True renal artery aneurysms (RAAs) are rare and traditionally have not been included in reviews of VAA because they have different clinical manifestations and are frequently associated with hypertension. The advent of interventional procedures in the liver has made traumatic intrahepatic aneurysm the most frequently encountered VAA at some institutions (2). The prevalence of iatrogenic aneurysms of the renal arteries and their branches is increasing for similar reasons (3).
The way in which a VAA manifests itself is also changing. An early study by Stanley et al (4) reported rupture in up to 22% of cases, whereas recent reports include large numbers of asymptomatic patients in whom aneurysms are discovered incidentally (5). Because most reports of VAA suffer from small numbers of patients with limited follow-up, recommendations concerning management are too often arbitrary. The routine use of computed tomography (CT) and magnetic resonance (MR) imaging has led to the increased diagnosis of both symptomatic and asymptomatic VAAs. CT and MR angiography are powerful tools for diagnosis and treatment planning in patients with VAA. Increasingly faster speed and higher spatial resolution make CT a first-line imaging modality for patients who present to the emergency department with abdominal pain. When a VAA ruptures, intraperitoneal or retroperitoneal hemorrhage or hematoma in a visceral organ or in the course of a visceral artery can be seen at CT. Although to our knowledge no reliable sign to suggest an impending rupture has been reported, rapid size increase in a known VAA may be predictive. Evidence suggesting an inflammatory or infectious cause includes a soft-tissue mass with stranding or gas adjacent to the aneurysm.
VAAs include both (a) true aneurysms with all three layers of the arterial wall intact; and (b) pseudoaneurysms, which lack a complete arterial wall. Most VAAs are degenerative, demonstrating deficiency of the arterial media with loss or fragmentation of elastic fibers and reduced smooth muscle. Atherosclerosis, fibromuscular dysplasia, and collagen disorders are other possible causes of VAA (6). Pseudoaneurysms can develop as a result of trauma, inflammation, infection, or vasculitis. In addition, pancreatitis, with the escape of pancreatic enzymes, may promote destruction of the arterial wall, resulting in pseudoaneurysms of the splenic, hepatic, gastroduodenal, and pancreaticoduodenal arteries (7–9).
VAAs can be treated with surgical or endovascular approaches. Management depends in part on the location of the aneurysm, with an endovascular approach being most appropriate for aneurysms involving the parenchymal branches of the hepatic, splenic, and renal arteries or pancreaticoduodenal arterial branches. Pathologic conditions, especially comorbidities, often favor an endovascular approach. Available expertise is an additional consideration in management decisions. Finally, emerging technologies are expanding the role of endovascular management.
Surgical and endovascular treatment of VAA share the common goal of preventing aneurysm expansion and rupture. This goal is best accomplished by excluding the aneurysm from the arterial circulation and pressure. In the presence of adequate collateral flow, surgical management consists of ligation of the parent artery proximal and distal to the aneurysm. This approach is appropriate for splenic artery aneurysms (SAAs) with collateral flow from the short gastric arteries and gastroepiploic arteries to the distal splenic artery and spleen (1). The celiac trunk, proximal SMA, and common hepatic artery (CHA) may also be ligated, with collateral flow provided by the pancreaticoduodenal and gastroduodenal arteries. For a proper hepatic artery (PHA) and a main renal artery (MRA) that lack collateral flow, and for celiac arteries and SMAs with inadequate collateral flow, ligation must be accompanied by arterial bypass surgery (1,10).
Endovascular management should also achieve isolation of the aneurysm from the arterial circulation. This isolation can be accomplished in several ways. For aneurysms involving large arteries (eg, the splenic artery), the aneurysm can be "trapped" between coils placed in the parent artery distal and then proximal to the aneurysm, thereby eliminating both prograde flow and the potential for retrograde flow to the aneurysm (Figs 1, 2). For aneurysms involving smaller arteries, the distal parent artery or its branches can be occluded with large particles, followed by coil placement in the larger proximal parent artery, again trapping the aneurysm and isolating it from the circulation (Fig 3) (9,11–13).
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Figure 1. Drawing illustrates how coils are placed distal and then proximal to the aneurysm, thereby trapping the aneurysm and isolating it from the circulation, with resultant thrombosis of the aneurysm.
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Figure 2a. Pseudoaneurysm in a 59-year-old alcoholic man who presented with acute upper gastrointestinal hemorrhage. The patient had a history of recurrent acute pancreatitis. (a) Arteriogram of the superior mesenteric artery (S) demonstrates retrograde filling of the proper hepatic artery (P) through the inferior pancreaticoduodenal artery, pancreatic arcade, and gastroduodenal artery. The anterior (double arrows) and posterior (single arrow) superior pancreaticoduodenal arteries are seen, with a pseudoaneurysm (arrowhead) originating from the latter. (b) Angiogram obtained after selective injection of contrast material into the inferior pancreaticoduodenal artery better demonstrates the origin of the pseudoaneurysm (arrow). (c) Angiogram shows a catheter that was advanced into the posterior arcade artery and coils that were placed distal and then proximal to the pseudoaneurysm (arrowhead). (d) Postembolization arteriogram demonstrates coils (arrow and arrowhead) isolating the pseudoaneurysm from the circulation, resulting in thrombosis of the pseudoaneurysm.
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Figure 2b. Pseudoaneurysm in a 59-year-old alcoholic man who presented with acute upper gastrointestinal hemorrhage. The patient had a history of recurrent acute pancreatitis. (a) Arteriogram of the superior mesenteric artery (S) demonstrates retrograde filling of the proper hepatic artery (P) through the inferior pancreaticoduodenal artery, pancreatic arcade, and gastroduodenal artery. The anterior (double arrows) and posterior (single arrow) superior pancreaticoduodenal arteries are seen, with a pseudoaneurysm (arrowhead) originating from the latter. (b) Angiogram obtained after selective injection of contrast material into the inferior pancreaticoduodenal artery better demonstrates the origin of the pseudoaneurysm (arrow). (c) Angiogram shows a catheter that was advanced into the posterior arcade artery and coils that were placed distal and then proximal to the pseudoaneurysm (arrowhead). (d) Postembolization arteriogram demonstrates coils (arrow and arrowhead) isolating the pseudoaneurysm from the circulation, resulting in thrombosis of the pseudoaneurysm.
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Figure 2c. Pseudoaneurysm in a 59-year-old alcoholic man who presented with acute upper gastrointestinal hemorrhage. The patient had a history of recurrent acute pancreatitis. (a) Arteriogram of the superior mesenteric artery (S) demonstrates retrograde filling of the proper hepatic artery (P) through the inferior pancreaticoduodenal artery, pancreatic arcade, and gastroduodenal artery. The anterior (double arrows) and posterior (single arrow) superior pancreaticoduodenal arteries are seen, with a pseudoaneurysm (arrowhead) originating from the latter. (b) Angiogram obtained after selective injection of contrast material into the inferior pancreaticoduodenal artery better demonstrates the origin of the pseudoaneurysm (arrow). (c) Angiogram shows a catheter that was advanced into the posterior arcade artery and coils that were placed distal and then proximal to the pseudoaneurysm (arrowhead). (d) Postembolization arteriogram demonstrates coils (arrow and arrowhead) isolating the pseudoaneurysm from the circulation, resulting in thrombosis of the pseudoaneurysm.
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Figure 2d. Pseudoaneurysm in a 59-year-old alcoholic man who presented with acute upper gastrointestinal hemorrhage. The patient had a history of recurrent acute pancreatitis. (a) Arteriogram of the superior mesenteric artery (S) demonstrates retrograde filling of the proper hepatic artery (P) through the inferior pancreaticoduodenal artery, pancreatic arcade, and gastroduodenal artery. The anterior (double arrows) and posterior (single arrow) superior pancreaticoduodenal arteries are seen, with a pseudoaneurysm (arrowhead) originating from the latter. (b) Angiogram obtained after selective injection of contrast material into the inferior pancreaticoduodenal artery better demonstrates the origin of the pseudoaneurysm (arrow). (c) Angiogram shows a catheter that was advanced into the posterior arcade artery and coils that were placed distal and then proximal to the pseudoaneurysm (arrowhead). (d) Postembolization arteriogram demonstrates coils (arrow and arrowhead) isolating the pseudoaneurysm from the circulation, resulting in thrombosis of the pseudoaneurysm.
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Figure 3. Drawing illustrates how large particles or small coils are used to occlude outflow from the aneurysm, followed by placement of coils proximal to the aneurysm, again trapping the aneurysm, with resultant thrombosis.
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Care must be taken to ensure that any collateral vessels that might support continued perfusion of the aneurysm are occluded with either coils or particles.
Covered stents provide another means of excluding VAAs from the circulation. These stents are reserved for those major branches of the visceral or splanchnic arteries (11,14,15) for which preservation of arterial perfusion is required (Fig 4). Limitations of covered stents include delivery systems whose size and rigidity preclude stent placement in distal tortuous branches. Covered stents are usually reserved for arteries 6 mm or larger in diameter because of the risk of thrombosis of smaller vessels.
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Figure 4. Drawing illustrates a PHA aneurysm with inflow from the CHA and out-flow from the gastroduodenal artery and distal PHA. To preserve flow to the liver, a covered stent is placed across the aneurysm. Before stent placement, however, the gastroduodenal artery distal to the aneurysm is occluded with coils to exclude the aneurysm from the circulation and prevent retrograde filling of the liver.
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For saccular aneurysms, coil occlusion (as applied to berry aneurysms, for example) provides another option. If the aneurysm has a narrow neck, the coils are constrained within the aneurysm sac by the narrow neck (16,17). For wider-neck aneurysms, stent-assisted coil placement is appropriate. A stent is first placed across the neck of the aneurysm, followed by the insertion of coils into the aneurysm sac through the interstices of the stent, which in turn constrain the coils within the sac. Occasionally, glue or thrombin is injected into the coil-filled sac to hasten thrombosis.
Finally, thrombin injection as used in femoral artery pseudoaneurysms has been adopted for treatment of VAAs after a failed endovascular approach or as an alternative to endovascular treatment (18). Under CT or (preferably) ultrasonographic (US) guidance, a 20- or 22-gauge needle is introduced into the pseudoaneurysm and thrombin is injected until there is cessation of flow. This approach is most useful for small peripheral traumatic pseudoaneurysms of the liver, spleen, or kidney and has reportedly been used to treat pancreaticoduodenal aneurysms after endovascular treatment has failed.
Regardless of which treatment is chosen, careful postprocedural surveillance is required to ensure that there is no reperfusion of the aneurysm from collateral flow or expansion of the aneurysm owing to continued exposure to systemic arterial pressure. Although complete exclusion of the aneurysm from the arterial circulation guarantees successful treatment, coil occlusion or thrombin-induced thrombosis does not necessarily help achieve this goal, with aneurysm expansion or recurrence remaining a possibility. For this reason, interval noninvasive follow-up is mandatory.
In this article, we discuss and illustrate the use of cross-sectional imaging and endovascular therapy in the diagnosis and management of VAAs, including SAAs, hepatic artery aneurysms, gastroduodenal and pancreaticoduodenal artery aneurysms, RAAs, celiac artery aneurysms (CAAs), and SMA aneurysms.
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Splenic Artery Aneurysm
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SAAs are the most common type of VAA, accounting for 60% of all cases (1). SAAs are four times more common in women than in men. Most aneurysms are small (2–4 cm), asymptomatic, solitary, saccular, and located in the middle to distal splenic artery (1). Impending rupture of an SAA can produce left upper quadrant pain radiating to the subscapular region. Rupture is a catastrophic event, manifesting with pain and hypotension. The phenomenon of double rupture is seen in 20%–30% of patients: Initial rupture is contained within the lesser sac, followed by penetration of the lesser sac and free rupture into the peritoneal cavity (1).
SAA has strong associations with the female gender, pregnancy (1), and portal hypertension (19). Although there are multiple causes of SAA, most are degenerative, with fragmentation of the elastic fibers and loss of smooth muscle in the media (20). Pseudoaneurysms associated with pancreatitis and pancreatic pseudocysts are another frequent cause of SAA (7).
The strong association of SAA with the female gender, pregnancy, and parity is likely related to the hormonal effects of estrogen and progesterone, both with receptor sites in the arterial wall (21). Relaxin, a hormone seen late in pregnancy and responsible for the elasticity of the symphysis pubis, may also alter the elasticity of the arterial wall (22). The high-flow state associated with pregnancy further contributes to the deleterious effects on the arterial wall. Rupture of an SAA during pregnancy, most often in the third trimester, is a catastrophic event, with reported maternal and fetal mortality rates of 70% and 90%, respectively (23).
A review of SAA by Abbas et al in 2002 (24) included 207 patients, 78% of whom were treated nonsurgically and followed up for a mean time of 75 months. Aneurysms ranged from 0.8 to 5 cm in diameter. Interval growth was seen in 10.1% of cases; however, no aneurysms ruptured, nor were there complications of conservative management (24).
Ruptured and symptomatic SAAs require treatment, as do aneurysms in pregnant women or women of childbearing age. Patients with portal hypertension or who undergo liver transplantation are also candidates for treatment. Enlarging aneurysms and aneurysms 2.5–3 cm or more in diameter may require treatment. The age of the patient and comorbid conditions should be considered in making treatment decisions (1,19).
Surgical management of SAA includes ligation or aneurysm resection for lesions in the proximal or middle portion of the splenic artery. Bypass surgery is not required, since collateral flow via the short gastric arteries provides flow to the distal splenic artery. For lesions near the hilum of the spleen or involving intrasplenic branches, splenectomy is most often performed. Occasionally, distal pancreatectomy is performed in addition to splenectomy, especially in cases of ruptured aneurysms. Recent reports cite surgical mortality rates of 20% in the "rupture" group and 5% in the elective group (24).
Endovascular trapping of SAA provides a minimally invasive alternative to surgical ligation. In this procedure, the aneurysm is trapped by placing coils in the splenic artery, first distal and then proximal to the aneurysm, making certain that no collateral flow to the aneurysm remains (Fig 5). Collateral flow via the short gastric arteries provides distal perfusion to the spleen (Fig 6).
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Figure 5a. SAA. (a) Arteriogram shows an aneurysm (arrows) that originates from a parenchymal branch of the splenic artery. (b) Arteriogram shows that the branch has been selectively catheterized, with the catheter (arrow) advanced distal to the aneurysm. (c) Arteriogram shows coils (arrows) that were placed distal and then proximal to the neck of the aneurysm. (d) Arteriogram obtained upon completion of the procedure demonstrates occlusion of the aneurysm with preservation of flow to the spleen.
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Figure 5b. SAA. (a) Arteriogram shows an aneurysm (arrows) that originates from a parenchymal branch of the splenic artery. (b) Arteriogram shows that the branch has been selectively catheterized, with the catheter (arrow) advanced distal to the aneurysm. (c) Arteriogram shows coils (arrows) that were placed distal and then proximal to the neck of the aneurysm. (d) Arteriogram obtained upon completion of the procedure demonstrates occlusion of the aneurysm with preservation of flow to the spleen.
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Figure 5c. SAA. (a) Arteriogram shows an aneurysm (arrows) that originates from a parenchymal branch of the splenic artery. (b) Arteriogram shows that the branch has been selectively catheterized, with the catheter (arrow) advanced distal to the aneurysm. (c) Arteriogram shows coils (arrows) that were placed distal and then proximal to the neck of the aneurysm. (d) Arteriogram obtained upon completion of the procedure demonstrates occlusion of the aneurysm with preservation of flow to the spleen.
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Figure 5d. SAA. (a) Arteriogram shows an aneurysm (arrows) that originates from a parenchymal branch of the splenic artery. (b) Arteriogram shows that the branch has been selectively catheterized, with the catheter (arrow) advanced distal to the aneurysm. (c) Arteriogram shows coils (arrows) that were placed distal and then proximal to the neck of the aneurysm. (d) Arteriogram obtained upon completion of the procedure demonstrates occlusion of the aneurysm with preservation of flow to the spleen.
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Figure 6a. SAA. (a, b) Arteriograms show stainless steel coils (arrows) that were placed to occlude the middle third of the splenic artery. Perfusion of the distal portion of the splenic artery is preserved by means of collateral flow from the caudal pancreatic arteries (arrowheads in b). (c) Arteriogram shows pancreatic collateral vessels (arrowheads) and short gastric branches (arrow), all of which contribute to distal perfusion. Sacrifice of a portion of the main splenic artery is generally safe because collateral blood supply in the celiac and SMA distribution is extensive.
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Figure 6b. SAA. (a, b) Arteriograms show stainless steel coils (arrows) that were placed to occlude the middle third of the splenic artery. Perfusion of the distal portion of the splenic artery is preserved by means of collateral flow from the caudal pancreatic arteries (arrowheads in b). (c) Arteriogram shows pancreatic collateral vessels (arrowheads) and short gastric branches (arrow), all of which contribute to distal perfusion. Sacrifice of a portion of the main splenic artery is generally safe because collateral blood supply in the celiac and SMA distribution is extensive.
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Figure 6c. SAA. (a, b) Arteriograms show stainless steel coils (arrows) that were placed to occlude the middle third of the splenic artery. Perfusion of the distal portion of the splenic artery is preserved by means of collateral flow from the caudal pancreatic arteries (arrowheads in b). (c) Arteriogram shows pancreatic collateral vessels (arrowheads) and short gastric branches (arrow), all of which contribute to distal perfusion. Sacrifice of a portion of the main splenic artery is generally safe because collateral blood supply in the celiac and SMA distribution is extensive.
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Hepatic Artery Aneurysm
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Hepatic artery aneurysm, the second most common VAA, demonstrates a male predilection of 2:1 (2). Most hepatic artery aneurysms are solitary and historically have involved the hepatic artery outside the liver (66% of cases) (11). Aneurysm location often helps predict both cause and treatment strategy. Intrahepatic branch aneurysms are most frequently the result of trauma, iatrogenic injury from biopsy or intervention, infection, or vasculitis. In contrast, extrahepatic aneurysms are most often degenerative or dysplastic (25).
Although hepatic artery aneurysms may be discovered incidentally, many are symptomatic. These aneurysms may manifest with rupture into the peritoneal cavity or with gastrointestinal hemorrhage. The triad of epigastric pain, hemobilia, and obstructive jaundice (Quincke triad) is seen in one-third of symptomatic patients (26). Risk factors associated with rupture are poorly defined, and the prevalence of rupture is difficult to assess. Rupture has been reported in 20%–80% of cases (24), with mortality rates ranging from 21% to 35% (27).
Intrahepatic aneurysms, which previously required hepatic resection, are now easily treated with transcatheter coil occlusion or embolization. Collateral blood flow and oxygen delivery from the portal vein minimize ischemic complications. Aneurysms of the CHA may be surgically ligated or trapped with coils. Collateral flow through the gastroduodenal artery and its branches provides ample blood flow to the liver. Patients with extensive atherosclerosis or previous gastrointestinal surgery may lack collateral blood supply to the PHA. Aneurysms of the PHA (distal to the gastroduodenal artery) require surgical ligation and bypass surgery owing to the limited potential for collateral blood flow to the liver (Fig 7). Alternatively, endovascular treatment with placement of a covered stent across the aneurysm isolates the aneurysm from the circulation while preserving flow to the liver (Fig 8) (11).
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Figure 7a. PHA in a 25-year-old man who presented with spontaneous perforation of the sigmoid colon. US performed as part of the diagnostic work-up demonstrated a mass in the porta hepatis with arterial flow. (a) Selective arteriogram of the celiac artery demonstrates an aneurysm (arrow) of the PHA, a finding that, in conjunction with the mass seen at US, led to the diagnosis of Ehlers-Danlos syndrome. (b) Arteriogram shows coils (arrowhead) that were placed distal and then proximal to the aneurysm to occlude the PHA. Although occlusion of the PHA generally carries an unacceptable risk of liver ischemia, the presence of a replaced left hepatic artery off the left gastric artery was believed to diminish the risk in this case.
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Figure 7b. PHA in a 25-year-old man who presented with spontaneous perforation of the sigmoid colon. US performed as part of the diagnostic work-up demonstrated a mass in the porta hepatis with arterial flow. (a) Selective arteriogram of the celiac artery demonstrates an aneurysm (arrow) of the PHA, a finding that, in conjunction with the mass seen at US, led to the diagnosis of Ehlers-Danlos syndrome. (b) Arteriogram shows coils (arrowhead) that were placed distal and then proximal to the aneurysm to occlude the PHA. Although occlusion of the PHA generally carries an unacceptable risk of liver ischemia, the presence of a replaced left hepatic artery off the left gastric artery was believed to diminish the risk in this case.
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Figure 8a. PHA pseudoaneurysm in a patient who developed brisk hemorrhage from a Jackson-Pratt drain placed during a Whipple procedure. The procedure had been performed for duodenal carcinoma 2 months earlier. The drain had been left in place because of a persistent anastomotic leak. (a) Arteriogram demonstrates a pseudoaneurysm (arrow) at the gastroduodenal artery stump. The drain (arrowheads) can be seen in the background. Trapping of the pseudoaneurysm would have involved occlusion of the proximal PHA with significant risk of liver ischemia. (b) Arteriogram shows a covered stent (arrows) that was placed to connect the CHA to the PHA, thereby occluding the pseudoaneurysm and providing continued hepatic perfusion.
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Figure 8b. PHA pseudoaneurysm in a patient who developed brisk hemorrhage from a Jackson-Pratt drain placed during a Whipple procedure. The procedure had been performed for duodenal carcinoma 2 months earlier. The drain had been left in place because of a persistent anastomotic leak. (a) Arteriogram demonstrates a pseudoaneurysm (arrow) at the gastroduodenal artery stump. The drain (arrowheads) can be seen in the background. Trapping of the pseudoaneurysm would have involved occlusion of the proximal PHA with significant risk of liver ischemia. (b) Arteriogram shows a covered stent (arrows) that was placed to connect the CHA to the PHA, thereby occluding the pseudoaneurysm and providing continued hepatic perfusion.
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Gastroduodenal and Pancreaticoduodenal Artery Aneurysm
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In our experience, the prevalence of aneurysms and pseudoaneurysms of the gastroduodenal and pancreaticoduodenal arteries is higher than has been reported. These aneurysms are often complications of acute and chronic pancreatitis and pancreatic surgery (Fig 9). They may also be dysplastic or degenerative in otherwise healthy patients (1). Most of these aneurysms are symptomatic, manifesting with gastrointestinal, intraperitoneal, or retroperitoneal hemorrhage (Fig 10). Although these aneurysms may be approached surgically, difficulty of identification at the time of the procedure makes coil occlusion an attractive alternative. Boudghene et al (28) reported procedural success in all 32 pancreaticoduodenal aneurysms in which embolization was attempted. Recurrent bleeding requiring additional endovascular or surgical treatment was encountered in 37% of patients. Eventual clinical success was achieved in 25 (78%) of these patients, with a mortality rate of 16%. A number of patients in this series were treated with infusion of vasoconstrictors or thrombotic agents, which is not currently considered adequate therapy. Clinical success was achieved in 71% of a cohort of patients who were treated surgically at the same institutions during the same time period, with a 12% mortality rate (28). It must be emphasized that, when treating aneurysms in the pancreaticoduodenal distribution, careful search for and occlusion of collateral supply to these aneurysms is essential before ending the procedure. Interval follow-up, often including repeat arteriography, is necessary to ensure aneurysm occlusion.
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Figure 9a. Gastroduodenal artery pseudoaneurysm in a 57-year-old woman who presented with chronic pancreatitis and upper gastrointestinal tract hemorrhage. (a) Unenhanced CT scan shows pancreatic calcifications (arrow) and a retroperitoneal soft-tissue mass (arrowheads). (b) Contrast material–enhanced CT arteriogram demonstrates immediate enhancement of the mass (arrows). (c) Arteriogram of the CHA demonstrates a pseudoaneurysm originating from the junction of the gastroduodenal and proper hepatic arteries. (d) Arteriogram shows coils (arrows) that were placed to occlude the gastroduodenal artery and its proximal branches, thereby preventing retrograde flow to the pseudoaneurysm. (e) Arteriogram shows a covered stent (arrows) that was placed to complete pseudoaneurysm exclusion while maintaining perfusion of the PHA.
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Figure 9b. Gastroduodenal artery pseudoaneurysm in a 57-year-old woman who presented with chronic pancreatitis and upper gastrointestinal tract hemorrhage. (a) Unenhanced CT scan shows pancreatic calcifications (arrow) and a retroperitoneal soft-tissue mass (arrowheads). (b) Contrast material–enhanced CT arteriogram demonstrates immediate enhancement of the mass (arrows). (c) Arteriogram of the CHA demonstrates a pseudoaneurysm originating from the junction of the gastroduodenal and proper hepatic arteries. (d) Arteriogram shows coils (arrows) that were placed to occlude the gastroduodenal artery and its proximal branches, thereby preventing retrograde flow to the pseudoaneurysm. (e) Arteriogram shows a covered stent (arrows) that was placed to complete pseudoaneurysm exclusion while maintaining perfusion of the PHA.
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Figure 9c. Gastroduodenal artery pseudoaneurysm in a 57-year-old woman who presented with chronic pancreatitis and upper gastrointestinal tract hemorrhage. (a) Unenhanced CT scan shows pancreatic calcifications (arrow) and a retroperitoneal soft-tissue mass (arrowheads). (b) Contrast material–enhanced CT arteriogram demonstrates immediate enhancement of the mass (arrows). (c) Arteriogram of the CHA demonstrates a pseudoaneurysm originating from the junction of the gastroduodenal and proper hepatic arteries. (d) Arteriogram shows coils (arrows) that were placed to occlude the gastroduodenal artery and its proximal branches, thereby preventing retrograde flow to the pseudoaneurysm. (e) Arteriogram shows a covered stent (arrows) that was placed to complete pseudoaneurysm exclusion while maintaining perfusion of the PHA.
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Figure 9d. Gastroduodenal artery pseudoaneurysm in a 57-year-old woman who presented with chronic pancreatitis and upper gastrointestinal tract hemorrhage. (a) Unenhanced CT scan shows pancreatic calcifications (arrow) and a retroperitoneal soft-tissue mass (arrowheads). (b) Contrast material–enhanced CT arteriogram demonstrates immediate enhancement of the mass (arrows). (c) Arteriogram of the CHA demonstrates a pseudoaneurysm originating from the junction of the gastroduodenal and proper hepatic arteries. (d) Arteriogram shows coils (arrows) that were placed to occlude the gastroduodenal artery and its proximal branches, thereby preventing retrograde flow to the pseudoaneurysm. (e) Arteriogram shows a covered stent (arrows) that was placed to complete pseudoaneurysm exclusion while maintaining perfusion of the PHA.
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Figure 9e. Gastroduodenal artery pseudoaneurysm in a 57-year-old woman who presented with chronic pancreatitis and upper gastrointestinal tract hemorrhage. (a) Unenhanced CT scan shows pancreatic calcifications (arrow) and a retroperitoneal soft-tissue mass (arrowheads). (b) Contrast material–enhanced CT arteriogram demonstrates immediate enhancement of the mass (arrows). (c) Arteriogram of the CHA demonstrates a pseudoaneurysm originating from the junction of the gastroduodenal and proper hepatic arteries. (d) Arteriogram shows coils (arrows) that were placed to occlude the gastroduodenal artery and its proximal branches, thereby preventing retrograde flow to the pseudoaneurysm. (e) Arteriogram shows a covered stent (arrows) that was placed to complete pseudoaneurysm exclusion while maintaining perfusion of the PHA.
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Figure 10a. Pancreaticoduodenal artery aneurysms in a previously healthy 41-year-old woman who presented with acute onset of abdominal pain. (a) Emergent CT scan reveals retroperitoneal hemorrhage (arrowheads). (b) Arteriogram of the gastroduodenal artery demonstrates aneurysms (arrowheads) of the anterior and posterior superior pancreaticoduodenal arteries. (c) Arteriogram shows coils (arrowheads) that were placed to occlude the inferior pancreaticoduodenal artery, followed by particulate occlusion of the anterior and posterior superior pancreaticoduodenal arteries (arrow). It was thought that exclusion and thrombosis of the aneurysm had been achieved. (d) Arteriogram obtained following the injection of contrast material into the dorsal pancreatic artery demonstrates residual perfusion of the posterior superior pancreaticoduodenal branch aneurysm (arrowhead) via the pancreaticoduodenal artery. Following occlusion of this branch with 1000 µm of polyvinyl alcohol particles, there was no further filling of the aneurysm. Perfusion of the pancreas is maintained via the transverse pancreatic artery (arrow). This case demonstrates the importance of totally excluding visceral aneurysms from the circulation by seeking out and eliminating all collateral flow to the aneurysm.
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Figure 10b. Pancreaticoduodenal artery aneurysms in a previously healthy 41-year-old woman who presented with acute onset of abdominal pain. (a) Emergent CT scan reveals retroperitoneal hemorrhage (arrowheads). (b) Arteriogram of the gastroduodenal artery demonstrates aneurysms (arrowheads) of the anterior and posterior superior pancreaticoduodenal arteries. (c) Arteriogram shows coils (arrowheads) that were placed to occlude the inferior pancreaticoduodenal artery, followed by particulate occlusion of the anterior and posterior superior pancreaticoduodenal arteries (arrow). It was thought that exclusion and thrombosis of the aneurysm had been achieved. (d) Arteriogram obtained following the injection of contrast material into the dorsal pancreatic artery demonstrates residual perfusion of the posterior superior pancreaticoduodenal branch aneurysm (arrowhead) via the pancreaticoduodenal artery. Following occlusion of this branch with 1000 µm of polyvinyl alcohol particles, there was no further filling of the aneurysm. Perfusion of the pancreas is maintained via the transverse pancreatic artery (arrow). This case demonstrates the importance of totally excluding visceral aneurysms from the circulation by seeking out and eliminating all collateral flow to the aneurysm.
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Figure 10c. Pancreaticoduodenal artery aneurysms in a previously healthy 41-year-old woman who presented with acute onset of abdominal pain. (a) Emergent CT scan reveals retroperitoneal hemorrhage (arrowheads). (b) Arteriogram of the gastroduodenal artery demonstrates aneurysms (arrowheads) of the anterior and posterior superior pancreaticoduodenal arteries. (c) Arteriogram shows coils (arrowheads) that were placed to occlude the inferior pancreaticoduodenal artery, followed by particulate occlusion of the anterior and posterior superior pancreaticoduodenal arteries (arrow). It was thought that exclusion and thrombosis of the aneurysm had been achieved. (d) Arteriogram obtained following the injection of contrast material into the dorsal pancreatic artery demonstrates residual perfusion of the posterior superior pancreaticoduodenal branch aneurysm (arrowhead) via the pancreaticoduodenal artery. Following occlusion of this branch with 1000 µm of polyvinyl alcohol particles, there was no further filling of the aneurysm. Perfusion of the pancreas is maintained via the transverse pancreatic artery (arrow). This case demonstrates the importance of totally excluding visceral aneurysms from the circulation by seeking out and eliminating all collateral flow to the aneurysm.
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Figure 10d. Pancreaticoduodenal artery aneurysms in a previously healthy 41-year-old woman who presented with acute onset of abdominal pain. (a) Emergent CT scan reveals retroperitoneal hemorrhage (arrowheads). (b) Arteriogram of the gastroduodenal artery demonstrates aneurysms (arrowheads) of the anterior and posterior superior pancreaticoduodenal arteries. (c) Arteriogram shows coils (arrowheads) that were placed to occlude the inferior pancreaticoduodenal artery, followed by particulate occlusion of the anterior and posterior superior pancreaticoduodenal arteries (arrow). It was thought that exclusion and thrombosis of the aneurysm had been achieved. (d) Arteriogram obtained following the injection of contrast material into the dorsal pancreatic artery demonstrates residual perfusion of the posterior superior pancreaticoduodenal branch aneurysm (arrowhead) via the pancreaticoduodenal artery. Following occlusion of this branch with 1000 µm of polyvinyl alcohol particles, there was no further filling of the aneurysm. Perfusion of the pancreas is maintained via the transverse pancreatic artery (arrow). This case demonstrates the importance of totally excluding visceral aneurysms from the circulation by seeking out and eliminating all collateral flow to the aneurysm.
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Renal Artery Aneurysm
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Although RAAs have traditionally not been included in reviews of VAA, they are in fact the second or third most common VAA (15%–22% of cases) (12). RAAs are discovered at 0.3%–0.7% of autopsies and up to 1% of renal arteriographic procedures (29). These aneurysms have a female predilection. Most are saccular and noncalcified and tend to occur at the bifurcation of the MRA. Fibromuscular dysplasia is a common cause of RAAs, with degenerative aneurysms, vasculitis (Fig 11), and trauma (Fig 12) accounting for most of the others (30).
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Figure 11a. RAA in an 18-year-old man with a diagnosis of Behçet disease who had developed increasing left flank pain. (a) Abdominal CT scan demonstrates a contrast material–filled mass (arrowheads) in the left kidney. (b) Selective arteriogram of the left renal artery demonstrates a pseudoaneurysm (arrowheads) originating from the anterior superior segmental artery (double arrows). The posterior segmental artery (single arrow) is partially obstructed by the pseudoaneurysm. (c) Arteriogram shows a catheter that was advanced into the partially obstructed posterior segmental artery. (d) Arteriogram shows distal particulate occlusion and proximal coil occlusion (arrows), with preservation of flow to the remainder of the kidney.
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Figure 11b. RAA in an 18-year-old man with a diagnosis of Behçet disease who had developed increasing left flank pain. (a) Abdominal CT scan demonstrates a contrast material–filled mass (arrowheads) in the left kidney. (b) Selective arteriogram of the left renal artery demonstrates a pseudoaneurysm (arrowheads) originating from the anterior superior segmental artery (double arrows). The posterior segmental artery (single arrow) is partially obstructed by the pseudoaneurysm. (c) Arteriogram shows a catheter that was advanced into the partially obstructed posterior segmental artery. (d) Arteriogram shows distal particulate occlusion and proximal coil occlusion (arrows), with preservation of flow to the remainder of the kidney.
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Figure 11c. RAA in an 18-year-old man with a diagnosis of Behçet disease who had developed increasing left flank pain. (a) Abdominal CT scan demonstrates a contrast material–filled mass (arrowheads) in the left kidney. (b) Selective arteriogram of the left renal artery demonstrates a pseudoaneurysm (arrowheads) originating from the anterior superior segmental artery (double arrows). The posterior segmental artery (single arrow) is partially obstructed by the pseudoaneurysm. (c) Arteriogram shows a catheter that was advanced into the partially obstructed posterior segmental artery. (d) Arteriogram shows distal particulate occlusion and proximal coil occlusion (arrows), with preservation of flow to the remainder of the kidney.
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Figure 11d. RAA in an 18-year-old man with a diagnosis of Behçet disease who had developed increasing left flank pain. (a) Abdominal CT scan demonstrates a contrast material–filled mass (arrowheads) in the left kidney. (b) Selective arteriogram of the left renal artery demonstrates a pseudoaneurysm (arrowheads) originating from the anterior superior segmental artery (double arrows). The posterior segmental artery (single arrow) is partially obstructed by the pseudoaneurysm. (c) Arteriogram shows a catheter that was advanced into the partially obstructed posterior segmental artery. (d) Arteriogram shows distal particulate occlusion and proximal coil occlusion (arrows), with preservation of flow to the remainder of the kidney.
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Figure 12a. RAA in a patient who developed persistent hematuria following nephrostomy. (a) Arteriogram of the left renal artery demonstrates the penetration of a pseudoaneurysm (arrowheads) of the posterior segmental renal artery by the nephrostomy tube (arrow). (b) Arteriogram reveals that the pseudoaneurysm (arrowheads) is associated with an arteriovenous fistula with an early draining vein (arrows). (c) Arteriogram obtained following coil occlusion of the pseudoaneurysm and feeding artery (arrow) shows no filling of the pseudoaneurysm or fistula.
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Figure 12b. RAA in a patient who developed persistent hematuria following nephrostomy. (a) Arteriogram of the left renal artery demonstrates the penetration of a pseudoaneurysm (arrowheads) of the posterior segmental renal artery by the nephrostomy tube (arrow). (b) Arteriogram reveals that the pseudoaneurysm (arrowheads) is associated with an arteriovenous fistula with an early draining vein (arrows). (c) Arteriogram obtained following coil occlusion of the pseudoaneurysm and feeding artery (arrow) shows no filling of the pseudoaneurysm or fistula.
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Figure 12c. RAA in a patient who developed persistent hematuria following nephrostomy. (a) Arteriogram of the left renal artery demonstrates the penetration of a pseudoaneurysm (arrowheads) of the posterior segmental renal artery by the nephrostomy tube (arrow). (b) Arteriogram reveals that the pseudoaneurysm (arrowheads) is associated with an arteriovenous fistula with an early draining vein (arrows). (c) Arteriogram obtained following coil occlusion of the pseudoaneurysm and feeding artery (arrow) shows no filling of the pseudoaneurysm or fistula.
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Most RAAs are asymptomatic, but symptoms may develop from rupture, embolization of the peripheral vascular bed, or arterial thrombosis. RAAs are associated with hypertension in up to 73% of cases (30). Hypotheses regarding the pathophysiologic basis of hypertension include coexisting renal artery stenosis, microembolization from the aneurysm, compression or kinking of the renal artery or its branches, and turbulent flow. Improvement in hypertension following treatment has been reported (30), and hematuria has been reported in 30% of RAAs (12).
Management decisions should be based on patient age and gender, severity of hypertension, anticipated pregnancy, and anatomic features of the aneurysm. Although size greater than 2 cm is considered a threshold for surgical treatment, rupture of aneurysms less than 2 cm has been reported (10). Young women, especially those with anticipated pregnancy, are considered to be at high risk for rupture. The mortality rate for pregnant females with RAA rupture has been reported to be as high as 80% (29). Female patients of childbearing age and patients with refractory hypertension or evidence of embolization are candidates for surgical or endovascular intervention (12). Despite the size threshold for surgical treatment mentioned earlier, there are numerous reports of conservative management of RAAs (30,31). For aneurysms less than 2 cm, follow-up imaging with CT or MR imaging is appropriate.
Treatment of RAAs is determined by the anatomic location of the aneurysm. Branch RAAs are easily treated with embolization (Fig 13) (12). Aneurysms of the MRA may be treated with ligation and arterial bypass surgery, nephrectomy, or covered stent placement (Fig 14) (3,14,15).
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Figure 13a. Branch RAA in a 26-year-old professional baseball player who presented with accelerated hypertension. The patient was being treated for subacute bacterial endocarditis. (a) Unenhanced CT scan demonstrates a mass (arrowhead) in the renal hilum. (b) Abdominal aortogram demonstrates a pseudoaneurysm (arrow) originating from a branch of an accessory superior polar renal artery. (c) Arteriogram obtained after selective injection of contrast material into the accessory artery better demonstrates the pseudoaneurysm (arrow) originating from the anterior superior segmental artery. The pseudoaneurysm was treated with a combination of alcohol occlusion of the outflow parent artery and distal vascular bed and large particle occlusion of inflow to the pseudoaneurysm. (d) Arteriogram shows exclusion of the pseudoaneurysm.
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Figure 13b. Branch RAA in a 26-year-old professional baseball player who presented with accelerated hypertension. The patient was being treated for subacute bacterial endocarditis. (a) Unenhanced CT scan demonstrates a mass (arrowhead) in the renal hilum. (b) Abdominal aortogram demonstrates a pseudoaneurysm (arrow) originating from a branch of an accessory superior polar renal artery. (c) Arteriogram obtained after selective injection of contrast material into the accessory artery better demonstrates the pseudoaneurysm (arrow) originating from the anterior superior segmental artery. The pseudoaneurysm was treated with a combination of alcohol occlusion of the outflow parent artery and distal vascular bed and large particle occlusion of inflow to the pseudoaneurysm. (d) Arteriogram shows exclusion of the pseudoaneurysm.
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Figure 13c. Branch RAA in a 26-year-old professional baseball player who presented with accelerated hypertension. The patient was being treated for subacute bacterial endocarditis. (a) Unenhanced CT scan demonstrates a mass (arrowhead) in the renal hilum. (b) Abdominal aortogram demonstrates a pseudoaneurysm (arrow) originating from a branch of an accessory superior polar renal artery. (c) Arteriogram obtained after selective injection of contrast material into the accessory artery better demonstrates the pseudoaneurysm (arrow) originating from the anterior superior segmental artery. The pseudoaneurysm was treated with a combination of alcohol occlusion of the outflow parent artery and distal vascular bed and large particle occlusion of inflow to the pseudoaneurysm. (d) Arteriogram shows exclusion of the pseudoaneurysm.
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Figure 13d. Branch RAA in a 26-year-old professional baseball player who presented with accelerated hypertension. The patient was being treated for subacute bacterial endocarditis. (a) Unenhanced CT scan demonstrates a mass (arrowhead) in the renal hilum. (b) Abdominal aortogram demonstrates a pseudoaneurysm (arrow) originating from a branch of an accessory superior polar renal artery. (c) Arteriogram obtained after selective injection of contrast material into the accessory artery better demonstrates the pseudoaneurysm (arrow) originating from the anterior superior segmental artery. The pseudoaneurysm was treated with a combination of alcohol occlusion of the outflow parent artery and distal vascular bed and large particle occlusion of inflow to the pseudoaneurysm. (d) Arteriogram shows exclusion of the pseudoaneur | |
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Abstract
LEARNING OBJECTIVES
