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The radiological treatment of hepatic artery aneurysms
ClinicalRadiology (1995) 50, 792 796
The Radiological Treatment of Hepatic Artery Aneurysms P. J. O ' C O N N O R ,
A. G. CHALMERS,
P. M . C H E N N E L L S
a n d D . J. L I N T O T T
Leeds General Infirmary, Leeds, West Yorkshire, UK Improvements in the quality and availability of cross-sectional imaging should result in more frequent detection of hepatic artery aneurysms before rupture. Interventional radiological treatment for extra-hepatic lesions has not previously been discussed in the literature. We present two cases of extra-hepatic hepatic artery aneurysms treated using different endovascular techniques and discuss the relative merits of these approaches. O'Connor, P.J., C h a l m e r s , A . G . , C h e n n e l l s , P . M . & L i n t o t t , D . J . (1995) Clinical Radiology 50, 7 9 2 - 7 9 6 . The Radiological Treatment of Hepatic Artery Aneurysms
Accepted for Publication 10 July 1995 J
A n e u r y s m a l d i l a t a t i o n o f t h e h e p a t i c a r t e r y w a s first d e s c r i b e d b y W i l s o n in 1809 w i t h t h e first successful s u r g i c a l t r e a t m e n t r e p o r t e d in 1903 b y K e h r [1]. S u r g e r y remains the mainstay of treatment although with the advent of cross-sectional imaging and endovascular intervention radiologists are becoming increasingly i n v o l v e d in the m a n a g e m e n t o f t h e s e lesions. I m p r o v e m e n t s in t h e q u a l i t y a n d a v a i l a b i l i t y o f crosss e c t i o n a l i m a g i n g h a v e r e s u l t e d in a n i n c r e a s i n g n u m b e r of aneurysms being detected before rupture. This allows thorough pre-operative assessment with consideration of all p o s s i b l e t r e a t m e n t o p t i o n s . W h i l e t h e r o l e o f e m b o l i z a t i o n f o r i n t r a h e p a t i c a n e u r y s m s is a c c e p t e d [ 2 - 7 ] t h e r e is n o d i s c u s s i o n in the l i t e r a t u r e a b o u t i n t e r v e n t i o n a l r a d i o l o g i c a l a p p r o a c h e s f o r e x t r a h e p a t i c lesions. W e p r e s e n t t w o cases o f e x t r a - h e p a t i c h e p a t i c a r t e r y a n e u r y s m m a n a g e d b y differing i n t e r v e n t i o n a l r a d i o l o g i c a l t e c h n i q u e s a n d discuss t h e r e l a t i v e m e r i t s o f these approaches.
CASE REPORTS
Case 1. A 28-year-old man presented to the dyspepsia clinic with a 6month-history of mild episodic right upper quadrant pain. The patient was well and had been pain-free for ten weeks. There was a history of trauma seven years previously when the patient had been a motorcyclist involved in a road traffic accident resulting in a two month hospital stay. He required plastic surgery for friction burns but there was no history of abdominal injury at that time. There was no other past medical, family or drug history of note. Physical examination was unremarkable. The patient was referred for abdominal ultrasound (US) which demonstrated a 2.5cm cystic lesion in the region of the head of the pancreas. An endoscopic retrograde pancreatogram was normal. Upper abdominal CT scanning was performed pre- and postintravenous contrast enhancement. An enhancing 2.5cm lesion was demonstrated adjacent to the pancreatic head lying just to the right of the superior mesenteric vein (Fig. 1). The enhancement was comparable to that of the aorta and a vascular malformation or aneurysm was provisionally diagnosed. There was no CT or US evidence of previous pancreatitis. Mesenteric angiography showed a normal variant of vascular anatomy with the common hepatic artery arising from the superior mesenteric artery (SMA). A 2 3 cm smooth round aneurysm was demonstrated arising from the common hepatic artery immediately beyond its origin from the SMA and lying in the bifurcation between these two arteries (Fig. 2). The coeliac axis was occluded at its origin and was supplied by collaterals from the gastro-duodenal and right gastric arteries. The splenic artery also received collateral supply from an enlarged ascending left colic branch of the inferior mesenteric artery. The splenic, mesenteric and portal veins were all patent with no other Correspondence to: Dr P. J. O'Connor, Leeds General Infirmary, Great George St, Leeds, West Yorkshire, LSI 3EX, UK. 9 1995 The Royal Collegeof Radiologists.
aneurysms demonstrated. The aneurysm was felt to be secondary to his congenitally anormalous visceral supply causing increased flow through the collateral circulation. A post-traumatic aetiology was thought less likely as there was no history of abdominal trauma. In view of the potentially catastrophic consequences of rupture, it was decided that treatment of this aneurysm was essential. As the patient was asymptomatic at the time and was unwilling to undergo major surgery, it was decided, therefore, to treat the lesion by catheter embolization. The aneurysm was packed with seventeen steel coils of various sizes resulting in thrombosis of much of the lumen while preserving flow in both the hepatic artery and SMA (Fig. 3). Follow-up CT examination, one month after embolization, showed no contrast enhancement within the aneurysm; embolization had resulted in a 1 cm increase in the aneurysm diameter. Repeat angiography was performed one year after the initial embolization. The previously placed coils were unchanged in position but there was opacification of the entire aneurysm lumen (Fig. 4). A further twenty-four coils were introduced until the final coil caused extrusion of the catheter tip. Despite this the final check angiogram showed persistent peripheral opacification of the aneurysm lumen. Further angiography was performed nine months later and showed continued partial opacification of the aneurysm lumen. A further thirteen coils were introduced until, once again, the last coil caused extrusion of the catheter tip. The final contrast injection showed persistent but reduced opacification in the aneurysm (Fig. 5). Flow in the hepatic and superior mesenteric arteries was not compromised by the embolization procedures. It was felt that total obliteration of the lumen would not be achieved while there was still free flow in the hepatic artery across the neck of the aneurysm. The possibility of additional embolic occlusion of the hepatic artery was considered but the abnormal vascular anatomy made the outcome of this unpredictable in respect of both hepatic and gastric vascularity. We postulated that the large number of coils within the aneurysm would likely act as 'scaffolding' thereby reducing the risk of spontaneous rupture. Throughout this period of review and repeat embolization the patient had remained asymptomatic and in view of his continuing desire to avoid surgery it was decided to adopt a conservative approach with close clinical and radiological follow-up. To date he remains asymptomatic and follow-up CT scans have shown no increase in size of the aneurysm post-embolization six years after his initial presentation. Case 2. A 71-year-old man presented with a six month history of post-prandial epigastric pain. There was a past medical history of peptic ulcer disease with a truncal vagotomy and posterior gastro-enterostomy having been performed 20 years previously. There was also a past history of chronic obstructive airways disease and a cerebrovascular accident in 1972 from which he made a good recovery. There was no family history of note and medication included ranitidine 150 mg b.d. and gaviscon as required. Physical examination was unremarkable. An upper gastro-intestinal endoscopy showed no recurrent ulceration, though biopsies showed chronic helicobacter associated gastritis. The patient was given a one week course of eradication therapy which had no effect on his symptoms. Upper abdominal US was requested which demonstrated a 3.3cm aneurysm arising from the common hepatic artery. Contrast enhanced helical CT (Fig. 6) demonstrated the relationship of the aneurysm to the surrounding viscera and vessels.
HEPATIC ARTERY ANEURYSMS
793
Fig. 1 -- Contrast enhanced CT scan demonstrating the aneur3sm I.-\} lying between the inferior vena cava (I) and the superior mcscnteric xein (S) adjacent to the SMA. Aorta (Ao).
Angiography confirmed an eccentric fusiform aneurysm of the extrahepatic hepatic artery extending across the origin of the gastroduodenal artery (Fig. 7), In view of the nature of the lesion and the history of cerebrovascular and chronic airways disease it was felt that stenting would be the most appropriate therapeutic option. This was performed via a femoral approach using an 8 F delivery system and a 6 c m x 7 m m Strecker stent was positioned across the aneurysm (Fig. 8). There was no disruption of the hepatic arterial supply, though the stent had to be deployed across the gastroduodenal artery origin obliterating flow in this vessel. The patient went home the following day after a doppler US examination which confirmed normal flow through the stent with no flow in the aneurysm. Follow-up US showed no change in the appearances after three m o n t h s (Fig. 9). There was complete resolution of the patient's symptoms after the procedure.
DISCUSSION Twenty percent of splanchnic aneurysms arise from the
Fig. 2 -- Selective SMA angiogram. The aneurysm (arrow) arises from the c o m m o n hepatic artery just distal to its origin on the SMA. Retrograde filling of the spenic artery is noted (arrowhead) as the coeliac axis is occluded at its origin. 9 1995 The Royal College of Radiologists, Clinical Radiology, 50, 792 796.
Fig. 3 SMA artcriogram folto~xing coil cmbolization. There are multiple metallic coils x~ithin the aneurxsm (arrow) with obliteration of most of tlne lumen.
hepatic artery [8]. Extrahepatic aneurysms occur four times more frequently than intrahepatic lesions, with two thirds of the former arising from the common hepatic artery [9]. The condition is twice as prevalent in men. The current most common aetiologies, accounting for 90% of all hepatic artery aneurysms, are atherosclerosis (32%), medial necrosis (24%), post-traumatic/iatrogenic (22%) and inflammatory (10%) [8]. The clinical diagnosis is difficult due to the paucity of symptoms prior to rupture. Quincke described a classical triad of epigastric pain, haemobilia and jaundice [10], but this is rarely seen as 80% of patients present acutely following rupture of the aneurysm [6,7]. Rupture occurs with roughly equal frequency into the biliary tree or abdominal cavity [8,9]. Between 30% and 50% of aneurysms are incidental
Fig. 4 FoIIow-up study t year after initial coiI embolization. Recanalization of the aneurysm lumen has occured (arrow).
794
CLINICAL RADIOLOGY
Fig. 5 - Angiographic appearances after the third and final embolization. The aneurysm is now densely packed with coils and there is a small a m o u n t of persistent contrast opacification within the lumen.
findings at autopsy [8] suggesting that a significant number of aneurysms remain asymptomatic [6] throughout life. Unlike aortic aneurysms, the risk of rupture relative to size is unknown and the current advice is that all lesions warrant therapy. In both our cases, the patients presented with upper abdominal symptoms over a period of months. The patient in case 2 had a history suggestive of mesenteric angina and obtained immediate relief of his symptoms after stenting. Mesenteric ischaemia associated with hepatic aneurysms has been previously reported [12,13], though the patient had no evidence of a steal phenomenon at angiography. Of interest, his pain was reproduced by catheter manipulation and balloon inflation within the aneurysm during stent deployment. This suggests the lesion itself was symptomatic post-prandially which could be explained by distention of the aneurysm secondary to increased splanchnic blood flow
Fig. 6 - Contrast enhanced helical CT scan showing the aneurysm (A) lying anterior to the caudate lobe of the liver (L) closely related to the porta. Aorta (Ao).
Fig. 7 Selective coeliac axis arteriography. There is an eccentric fusiform aneurysm of the c o m m o n hepatic artery (arrow) arising just distal to a stenosis (arrowhead). The aneurysm extends almost to the gastroduodenal artery origin (curved arrow).
after meals. This could symptomatically mimic mesenteric angina. Patients with hepatic artery aneurysms noted at either CT or US require angiographic assessment because of the incidence of multiple lesions (20%) [2] and the considerable variation in the site of the hepatic artery origin. As angiographic assessment involves selective vascular access an endovascular therapeutic approach to these lesions would be advantageous. Potential radiological options include embolization of the aneurysm, stenting of the aneurysm and embolization of the common hepatic artery. The incidence of hepatic necrosis following interruption
Fig. 8 - Angiogram performed immediately after stent insertion. The stent (arrows) has been positioned between the c o m m o n hepatic artery and the hepatic artery proper. 9 1995 The Royal College of Radiologists, Clinical Radiology, 50, 792-796.
795
HEPATIC ARTERY ANEURYSMS
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" 1~,-I Q ,
: L
_:
o['[hc COllllnOll }lcpdiic d i [ c i \ J,, loxx duc to the ]]LIIliCTO[_I'~ collatcr~/I,, thole open Lip to supp13 the li\ cr [13 15]. Thi,, collalLcrgll supply is rcsponsil-lc I'or ~hc current. "
"LLpLLI]C Cd~.][ ILlvi]O]O~JC~I] LCCJ]ili,,_]LLO ]]L}'~ ~L<]\ LI]]LL~O~ all]~i
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eou, to ,,u~e~c~/ ]igzttion :rod. thcir ~ould bc n~ost >Llitctblc [o] twc-gc~str,~ciLtodenail le~,iol>,. It would bc tcchnic~ll\ it>-, dcmaulding than stcnting or cn]boli• o1 the ~tncul\>l]l thoLIgh, lhcorcdcullx, could c o m p r o nlisc g~>,t]ic o] hcp~[lic peFi'u>ion, in post-gastroduoden~d ~lnd >uituble prc-gastroduodcned lesions embolizLLtion of t h e a n e u r \ snq itscll Ol- stcnting ~ue I"31"ofc]'ablc as these >hould nqaintuin normal] hep~tic arterial tto\~. The choice bct~\ een these two is determined mainly by the configuration of the lesion. In atleur\sms with a clearly identifiable neck embolization of the aneuiysm itself can be performed. Embolization using gelfoam has been described but is associated with reports of aneurysm rupture during the procedure presumed to be secondary to the high injection pressure [20]. As a result. low pressure techniques such as metallic coils or detachable balloons are advised, most experience is available using coil embotization. Losing a coil distally into the intrahepatic circulation is associated with a risk of hepatic bed infarction. This is rarely a problem as there is compensation by both portal flow and intrahepatic collaterals. Conventional steel coils can produce a high radial force and care must be taken during deployment not to cause excessive enlargement which could cause rupture. Coil embolization has limitations for aneurysms with a wide neck where it may prove impossible to obliterate flow as we found in case 1. This is because flow past a wide-necked aneurysm produces turbulence within the aneurysm preventing effective thrombosis of the lumen.
to
pre-gastroduodcnLt]
dnctiI\sll]>.
1]L].nlcl\
ligeition of the con]l]lOI1 hepL/tic after\. The n~ujo,it> oi" authors would not recommend this approL~ch ~'or pos> gastroduodenal lesions as dcprixing the li\er olcollatcr>~l gastroduodcnal flow theoreticall, increases the risk oi hepatic necrosis [8.16]. Although there are numerous, st,trgical operations described for post-g~stroduodcmd lesions, the common features are repair or excision oi the aneurysm with vascular reconstruction of ~t~c arterial supply to the liver. The factors which influence the radiological management of extrahepatic aneurysms are the presentation of the patient, the site relative to the gastroduodenal artery and, most importantly, the morphology of the lesion. In the acute patient, who presents following rupture. the diagnosis will rarely be suspected clinically but CT scanning or US may demonstrate the lesion. Embolization of the aneurysm or c o m m o n hepatic artery would be an appropriate therapy mainly in view of the shorter procedure time. M a n y of these patients are in extremis and require rapid therapeutic intervention with surgery carrying a high mortality (80%) [8,18]. A reported disadvantage of ligation (which also applies to embolization of the feeding artery) is that distal flow is not reliably stopped and bleeding may continue [2]. The potential for back-filling should be borne in mind with embolization both proximal and distal to the lesion. An alternative approach would be balloon occlusion of the feeding vessel to reduce bloodless, allowing the patient to go to theatre in a more controlled environment. In patients where the aneurysm is detected prior to 9 1995 The Royal College of Radiologists, Clinical Radiology, 50, 792-796.
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COllllllOl]
ht..'pL[t]c
L/TLCT\_ i> ~i[]~]lO-
796
CLINICAL RADIOLOGY
Fusiform aneurysms with no identifiable neck, as in case 2, are obviously unsuitable for embolization if normal hepatic perfusion is to be maintained. In these situations stenting is appropriate as this effectively eradicates flow in the aneurysm while maintaining hepatic arterial perfusion. Intraarterial stents were first introduced for the treatment of stenotic disease [21] and their effectiveness has resulted in a proliferation of applications including the treatment of aneurysms [22]. Stenting can be performed in both pre- and post-gastroduodenal aneurysms. An uncovered stent (as used in case 2) has, in our experience, been sufficient to eradicate flow in an aneurysm of this size. Covered stents with a double meshwork offer theoretical advantages in treating large lesions and, in the future, may be shown to be preferable. Although stenting is the most expensive and technically the most demanding radiological treatment option it offers the most advantage to the patient. It fulfills the treatment requirements obliterating flow within the aneurysm and maintains normal hepatic perfusion while avoiding the need for general anaesthesia. The use of intra-arterial stents in the treatment of hepatic artery aneurysms has, to our knowledge, not been previously described in the medical literature and represents a promising new approach to the management of these difficult lesions. CONCLUSIONS
Radiological management of hepatic artery aneurysms have obvious advantages over surgery. The avoidance of general anaesthesia and less iatrogenic trauma should result in shorter hospital stays. Endovascular stenting or embolization of the aneurysm lumen are the preferred approaches to extrahepatic hepatic artery aneurysms with the site and morphology of the lesion determining the specific technique. In patients presenting acutely, embolization of either the common hepatic artery, the aneurysm itself or the feeding vessel are possible therapeutic options, all of which compare favorably to surgery which carries a high mortality.
REFERENCES
1 Guida PM, Moore SW. Aneurysm of the hepatic artery. Report of five cases with a brief review of the previously reported cases. Surgery 1966;60:299-303. 2 Kadir S, Athanasoulis CA, Ring EJ et al. Transcatheter embolization ofintrahepatic artery aneurysms. Radiology 1980; 134:335-339.
3 Jonsson K, Bjernstad A, Eriksson B. Treatment of a hepatic artery aneurysm by coil occlusion of the hepatic artery. Amerieal Journal o f Roentgenology 1980;134:1245-1247. 4 0 k a z a k i M, Higashihara H, Ono H et al. Percutaneous embolization of ruptured splanchnic artery pseudoaneurysms. Acta Radiology 1991;32:349-354. 5 Uflacker R. Transcatheter embolization of arterial aneurysms. British Journal of Radiology 1986;59:317-324. 6 Baker KS, Tisnado J, Cho SR et al. Splanchnic artery aneurysms and pseudoaneurysms: transcatheter embolization. Radiology 1987;163:135-139. 7 Salam TA, Lumsden AB, Martin LG et al. Nonoperative management of visceral aneurysms and pseudoaneurysms. American JournalofSurgery 1992;164:215 219. 8 Countryman D, Norwood S, Register D et al. Hepatic artery aneurysm. Report of an unusual case and review of the literature. American Surgeon 1983;49:51-54. 9 Kibbler CC, Cohen DL, Cruicshank JK et al. Use of CAT scanning in the diagnosis and management of hepatic artery aneurysm. Gut 1985;26:752-756. 10 Harlaftis NN, AKkin JT Hemobilia from ruptured hepatic artery aneurysm. American Journal of Surgery 1977;133:229-232. 11 Gryboski JD, Clemett A. Congenital hepatic artery aneurysm with superior mesenteric artery insufficiency: a steal syndrome. Pediatics 1967;39:344-347. 12 Rieser R, Hauger W. Aneurysm of the proper hepatic artery as a cause of abdominal angina. (in German). Rontgen-Blatter 1988;41:366-368. 13 Bengrnark S, Rosengren K. Angiographic study of the collateral circulation to the liver after ligation of the hepatic artery in man. American Journal o f Surgery 1970;119:620-624. 14 Michels NA. Newer anatomy of the liver and its varient blood supply and collateral circulation. American Journal o f Surgery 1966;112:337-347. 15 Koehler RE, Korobkin M, Lewis F. Arteriographic demonstration of collateral arterial supply ot the liver after hepatic ligation. Radiology 1975;117:49-54. 16 Psathakis D, Muller G Noah M e t al. Present management of hepatic artery aneurysms. Symptomatic left hepatic artery aneurysm; fight hepatic artery aneurysm with erosion into the gallblader and simultaneous colocholecystic fistula - a report of two unusual cases and the current state of etiology, diagnosis, histology and treatment. Vase-Journal o f Vascular Diseases 1992;21:210-215. 17 Tsai CH, Mo LR, Chiou CY et al. Therapeutic embolization of post-cholecystectomy hepatic artery aneurysm. Hepato-Gastroenterology 1992;39:158 160. 18 Goldblatt M, Goldin AR, Schaff MI. Percutaneous embolization for the management of hepatic artery aneurysms. Gastroenterology 1977;73:1142-1146. 19 Sutton D, Lawton G. Angiographic diagnosis of aneurysms involving the hepitoc artery. Clinical Radiology 1973;24:43-48. 20 Lina JR, Jacques P, Mandell V. Aneurysm rupture secondary to transcatheter embolization. American Journal of Roentgenology 1979;132:553-556. 21 Strecker EP, Liermann D, Barth KH et al. Expandible tubular stents for the tratment of arterial occlusive diseases: Experimental and clinical results. Radiology 1990; 175:97-102. 22 Althoff M, Schulte E, Ranft J et al. Occlusion of peripheral aneurysms by arterial stent implantation in inoperable patients a methodologic alternative? (in German). Vasa Suppl. 1992;35:184185.
9 1995 The Royal College of Radiologists, ClinicalRadiology, 50, 792-796.
The Radiological Treatment of Hepatic Artery Aneurysms P. J. O ' C O N N O R ,
A. G. CHALMERS,
P. M . C H E N N E L L S
a n d D . J. L I N T O T T
Leeds General Infirmary, Leeds, West Yorkshire, UK Improvements in the quality and availability of cross-sectional imaging should result in more frequent detection of hepatic artery aneurysms before rupture. Interventional radiological treatment for extra-hepatic lesions has not previously been discussed in the literature. We present two cases of extra-hepatic hepatic artery aneurysms treated using different endovascular techniques and discuss the relative merits of these approaches. O'Connor, P.J., C h a l m e r s , A . G . , C h e n n e l l s , P . M . & L i n t o t t , D . J . (1995) Clinical Radiology 50, 7 9 2 - 7 9 6 . The Radiological Treatment of Hepatic Artery Aneurysms
Accepted for Publication 10 July 1995 J
A n e u r y s m a l d i l a t a t i o n o f t h e h e p a t i c a r t e r y w a s first d e s c r i b e d b y W i l s o n in 1809 w i t h t h e first successful s u r g i c a l t r e a t m e n t r e p o r t e d in 1903 b y K e h r [1]. S u r g e r y remains the mainstay of treatment although with the advent of cross-sectional imaging and endovascular intervention radiologists are becoming increasingly i n v o l v e d in the m a n a g e m e n t o f t h e s e lesions. I m p r o v e m e n t s in t h e q u a l i t y a n d a v a i l a b i l i t y o f crosss e c t i o n a l i m a g i n g h a v e r e s u l t e d in a n i n c r e a s i n g n u m b e r of aneurysms being detected before rupture. This allows thorough pre-operative assessment with consideration of all p o s s i b l e t r e a t m e n t o p t i o n s . W h i l e t h e r o l e o f e m b o l i z a t i o n f o r i n t r a h e p a t i c a n e u r y s m s is a c c e p t e d [ 2 - 7 ] t h e r e is n o d i s c u s s i o n in the l i t e r a t u r e a b o u t i n t e r v e n t i o n a l r a d i o l o g i c a l a p p r o a c h e s f o r e x t r a h e p a t i c lesions. W e p r e s e n t t w o cases o f e x t r a - h e p a t i c h e p a t i c a r t e r y a n e u r y s m m a n a g e d b y differing i n t e r v e n t i o n a l r a d i o l o g i c a l t e c h n i q u e s a n d discuss t h e r e l a t i v e m e r i t s o f these approaches.
CASE REPORTS
Case 1. A 28-year-old man presented to the dyspepsia clinic with a 6month-history of mild episodic right upper quadrant pain. The patient was well and had been pain-free for ten weeks. There was a history of trauma seven years previously when the patient had been a motorcyclist involved in a road traffic accident resulting in a two month hospital stay. He required plastic surgery for friction burns but there was no history of abdominal injury at that time. There was no other past medical, family or drug history of note. Physical examination was unremarkable. The patient was referred for abdominal ultrasound (US) which demonstrated a 2.5cm cystic lesion in the region of the head of the pancreas. An endoscopic retrograde pancreatogram was normal. Upper abdominal CT scanning was performed pre- and postintravenous contrast enhancement. An enhancing 2.5cm lesion was demonstrated adjacent to the pancreatic head lying just to the right of the superior mesenteric vein (Fig. 1). The enhancement was comparable to that of the aorta and a vascular malformation or aneurysm was provisionally diagnosed. There was no CT or US evidence of previous pancreatitis. Mesenteric angiography showed a normal variant of vascular anatomy with the common hepatic artery arising from the superior mesenteric artery (SMA). A 2 3 cm smooth round aneurysm was demonstrated arising from the common hepatic artery immediately beyond its origin from the SMA and lying in the bifurcation between these two arteries (Fig. 2). The coeliac axis was occluded at its origin and was supplied by collaterals from the gastro-duodenal and right gastric arteries. The splenic artery also received collateral supply from an enlarged ascending left colic branch of the inferior mesenteric artery. The splenic, mesenteric and portal veins were all patent with no other Correspondence to: Dr P. J. O'Connor, Leeds General Infirmary, Great George St, Leeds, West Yorkshire, LSI 3EX, UK. 9 1995 The Royal Collegeof Radiologists.
aneurysms demonstrated. The aneurysm was felt to be secondary to his congenitally anormalous visceral supply causing increased flow through the collateral circulation. A post-traumatic aetiology was thought less likely as there was no history of abdominal trauma. In view of the potentially catastrophic consequences of rupture, it was decided that treatment of this aneurysm was essential. As the patient was asymptomatic at the time and was unwilling to undergo major surgery, it was decided, therefore, to treat the lesion by catheter embolization. The aneurysm was packed with seventeen steel coils of various sizes resulting in thrombosis of much of the lumen while preserving flow in both the hepatic artery and SMA (Fig. 3). Follow-up CT examination, one month after embolization, showed no contrast enhancement within the aneurysm; embolization had resulted in a 1 cm increase in the aneurysm diameter. Repeat angiography was performed one year after the initial embolization. The previously placed coils were unchanged in position but there was opacification of the entire aneurysm lumen (Fig. 4). A further twenty-four coils were introduced until the final coil caused extrusion of the catheter tip. Despite this the final check angiogram showed persistent peripheral opacification of the aneurysm lumen. Further angiography was performed nine months later and showed continued partial opacification of the aneurysm lumen. A further thirteen coils were introduced until, once again, the last coil caused extrusion of the catheter tip. The final contrast injection showed persistent but reduced opacification in the aneurysm (Fig. 5). Flow in the hepatic and superior mesenteric arteries was not compromised by the embolization procedures. It was felt that total obliteration of the lumen would not be achieved while there was still free flow in the hepatic artery across the neck of the aneurysm. The possibility of additional embolic occlusion of the hepatic artery was considered but the abnormal vascular anatomy made the outcome of this unpredictable in respect of both hepatic and gastric vascularity. We postulated that the large number of coils within the aneurysm would likely act as 'scaffolding' thereby reducing the risk of spontaneous rupture. Throughout this period of review and repeat embolization the patient had remained asymptomatic and in view of his continuing desire to avoid surgery it was decided to adopt a conservative approach with close clinical and radiological follow-up. To date he remains asymptomatic and follow-up CT scans have shown no increase in size of the aneurysm post-embolization six years after his initial presentation. Case 2. A 71-year-old man presented with a six month history of post-prandial epigastric pain. There was a past medical history of peptic ulcer disease with a truncal vagotomy and posterior gastro-enterostomy having been performed 20 years previously. There was also a past history of chronic obstructive airways disease and a cerebrovascular accident in 1972 from which he made a good recovery. There was no family history of note and medication included ranitidine 150 mg b.d. and gaviscon as required. Physical examination was unremarkable. An upper gastro-intestinal endoscopy showed no recurrent ulceration, though biopsies showed chronic helicobacter associated gastritis. The patient was given a one week course of eradication therapy which had no effect on his symptoms. Upper abdominal US was requested which demonstrated a 3.3cm aneurysm arising from the common hepatic artery. Contrast enhanced helical CT (Fig. 6) demonstrated the relationship of the aneurysm to the surrounding viscera and vessels.
HEPATIC ARTERY ANEURYSMS
793
Fig. 1 -- Contrast enhanced CT scan demonstrating the aneur3sm I.-\} lying between the inferior vena cava (I) and the superior mcscnteric xein (S) adjacent to the SMA. Aorta (Ao).
Angiography confirmed an eccentric fusiform aneurysm of the extrahepatic hepatic artery extending across the origin of the gastroduodenal artery (Fig. 7), In view of the nature of the lesion and the history of cerebrovascular and chronic airways disease it was felt that stenting would be the most appropriate therapeutic option. This was performed via a femoral approach using an 8 F delivery system and a 6 c m x 7 m m Strecker stent was positioned across the aneurysm (Fig. 8). There was no disruption of the hepatic arterial supply, though the stent had to be deployed across the gastroduodenal artery origin obliterating flow in this vessel. The patient went home the following day after a doppler US examination which confirmed normal flow through the stent with no flow in the aneurysm. Follow-up US showed no change in the appearances after three m o n t h s (Fig. 9). There was complete resolution of the patient's symptoms after the procedure.
DISCUSSION Twenty percent of splanchnic aneurysms arise from the
Fig. 2 -- Selective SMA angiogram. The aneurysm (arrow) arises from the c o m m o n hepatic artery just distal to its origin on the SMA. Retrograde filling of the spenic artery is noted (arrowhead) as the coeliac axis is occluded at its origin. 9 1995 The Royal College of Radiologists, Clinical Radiology, 50, 792 796.
Fig. 3 SMA artcriogram folto~xing coil cmbolization. There are multiple metallic coils x~ithin the aneurxsm (arrow) with obliteration of most of tlne lumen.
hepatic artery [8]. Extrahepatic aneurysms occur four times more frequently than intrahepatic lesions, with two thirds of the former arising from the common hepatic artery [9]. The condition is twice as prevalent in men. The current most common aetiologies, accounting for 90% of all hepatic artery aneurysms, are atherosclerosis (32%), medial necrosis (24%), post-traumatic/iatrogenic (22%) and inflammatory (10%) [8]. The clinical diagnosis is difficult due to the paucity of symptoms prior to rupture. Quincke described a classical triad of epigastric pain, haemobilia and jaundice [10], but this is rarely seen as 80% of patients present acutely following rupture of the aneurysm [6,7]. Rupture occurs with roughly equal frequency into the biliary tree or abdominal cavity [8,9]. Between 30% and 50% of aneurysms are incidental
Fig. 4 FoIIow-up study t year after initial coiI embolization. Recanalization of the aneurysm lumen has occured (arrow).
794
CLINICAL RADIOLOGY
Fig. 5 - Angiographic appearances after the third and final embolization. The aneurysm is now densely packed with coils and there is a small a m o u n t of persistent contrast opacification within the lumen.
findings at autopsy [8] suggesting that a significant number of aneurysms remain asymptomatic [6] throughout life. Unlike aortic aneurysms, the risk of rupture relative to size is unknown and the current advice is that all lesions warrant therapy. In both our cases, the patients presented with upper abdominal symptoms over a period of months. The patient in case 2 had a history suggestive of mesenteric angina and obtained immediate relief of his symptoms after stenting. Mesenteric ischaemia associated with hepatic aneurysms has been previously reported [12,13], though the patient had no evidence of a steal phenomenon at angiography. Of interest, his pain was reproduced by catheter manipulation and balloon inflation within the aneurysm during stent deployment. This suggests the lesion itself was symptomatic post-prandially which could be explained by distention of the aneurysm secondary to increased splanchnic blood flow
Fig. 6 - Contrast enhanced helical CT scan showing the aneurysm (A) lying anterior to the caudate lobe of the liver (L) closely related to the porta. Aorta (Ao).
Fig. 7 Selective coeliac axis arteriography. There is an eccentric fusiform aneurysm of the c o m m o n hepatic artery (arrow) arising just distal to a stenosis (arrowhead). The aneurysm extends almost to the gastroduodenal artery origin (curved arrow).
after meals. This could symptomatically mimic mesenteric angina. Patients with hepatic artery aneurysms noted at either CT or US require angiographic assessment because of the incidence of multiple lesions (20%) [2] and the considerable variation in the site of the hepatic artery origin. As angiographic assessment involves selective vascular access an endovascular therapeutic approach to these lesions would be advantageous. Potential radiological options include embolization of the aneurysm, stenting of the aneurysm and embolization of the common hepatic artery. The incidence of hepatic necrosis following interruption
Fig. 8 - Angiogram performed immediately after stent insertion. The stent (arrows) has been positioned between the c o m m o n hepatic artery and the hepatic artery proper. 9 1995 The Royal College of Radiologists, Clinical Radiology, 50, 792-796.
795
HEPATIC ARTERY ANEURYSMS
I " <) ] ,~] !!/~,U, nA] ~o[ Xt/ll]o,,'~ ~,,']~/~: I ' l ~TC /:Evil "31] Oli//vLl[ ~ :1 ' ! , ' L , / \ ~ : 1 ]
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_:
o['[hc COllllnOll }lcpdiic d i [ c i \ J,, loxx duc to the ]]LIIliCTO[_I'~ collatcr~/I,, thole open Lip to supp13 the li\ cr [13 15]. Thi,, collalLcrgll supply is rcsponsil-lc I'or ~hc current. "
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eou, to ,,u~e~c~/ ]igzttion :rod. thcir ~ould bc n~ost >Llitctblc [o] twc-gc~str,~ciLtodenail le~,iol>,. It would bc tcchnic~ll\ it>-, dcmaulding than stcnting or cn]boli• o1 the ~tncul\>l]l thoLIgh, lhcorcdcullx, could c o m p r o nlisc g~>,t]ic o] hcp~[lic peFi'u>ion, in post-gastroduoden~d ~lnd >uituble prc-gastroduodcned lesions embolizLLtion of t h e a n e u r \ snq itscll Ol- stcnting ~ue I"31"ofc]'ablc as these >hould nqaintuin normal] hep~tic arterial tto\~. The choice bct~\ een these two is determined mainly by the configuration of the lesion. In atleur\sms with a clearly identifiable neck embolization of the aneuiysm itself can be performed. Embolization using gelfoam has been described but is associated with reports of aneurysm rupture during the procedure presumed to be secondary to the high injection pressure [20]. As a result. low pressure techniques such as metallic coils or detachable balloons are advised, most experience is available using coil embotization. Losing a coil distally into the intrahepatic circulation is associated with a risk of hepatic bed infarction. This is rarely a problem as there is compensation by both portal flow and intrahepatic collaterals. Conventional steel coils can produce a high radial force and care must be taken during deployment not to cause excessive enlargement which could cause rupture. Coil embolization has limitations for aneurysms with a wide neck where it may prove impossible to obliterate flow as we found in case 1. This is because flow past a wide-necked aneurysm produces turbulence within the aneurysm preventing effective thrombosis of the lumen.
to
pre-gastroduodcnLt]
dnctiI\sll]>.
1]L].nlcl\
ligeition of the con]l]lOI1 hepL/tic after\. The n~ujo,it> oi" authors would not recommend this approL~ch ~'or pos> gastroduodenal lesions as dcprixing the li\er olcollatcr>~l gastroduodcnal flow theoreticall, increases the risk oi hepatic necrosis [8.16]. Although there are numerous, st,trgical operations described for post-g~stroduodcmd lesions, the common features are repair or excision oi the aneurysm with vascular reconstruction of ~t~c arterial supply to the liver. The factors which influence the radiological management of extrahepatic aneurysms are the presentation of the patient, the site relative to the gastroduodenal artery and, most importantly, the morphology of the lesion. In the acute patient, who presents following rupture. the diagnosis will rarely be suspected clinically but CT scanning or US may demonstrate the lesion. Embolization of the aneurysm or c o m m o n hepatic artery would be an appropriate therapy mainly in view of the shorter procedure time. M a n y of these patients are in extremis and require rapid therapeutic intervention with surgery carrying a high mortality (80%) [8,18]. A reported disadvantage of ligation (which also applies to embolization of the feeding artery) is that distal flow is not reliably stopped and bleeding may continue [2]. The potential for back-filling should be borne in mind with embolization both proximal and distal to the lesion. An alternative approach would be balloon occlusion of the feeding vessel to reduce bloodless, allowing the patient to go to theatre in a more controlled environment. In patients where the aneurysm is detected prior to 9 1995 The Royal College of Radiologists, Clinical Radiology, 50, 792-796.
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796
CLINICAL RADIOLOGY
Fusiform aneurysms with no identifiable neck, as in case 2, are obviously unsuitable for embolization if normal hepatic perfusion is to be maintained. In these situations stenting is appropriate as this effectively eradicates flow in the aneurysm while maintaining hepatic arterial perfusion. Intraarterial stents were first introduced for the treatment of stenotic disease [21] and their effectiveness has resulted in a proliferation of applications including the treatment of aneurysms [22]. Stenting can be performed in both pre- and post-gastroduodenal aneurysms. An uncovered stent (as used in case 2) has, in our experience, been sufficient to eradicate flow in an aneurysm of this size. Covered stents with a double meshwork offer theoretical advantages in treating large lesions and, in the future, may be shown to be preferable. Although stenting is the most expensive and technically the most demanding radiological treatment option it offers the most advantage to the patient. It fulfills the treatment requirements obliterating flow within the aneurysm and maintains normal hepatic perfusion while avoiding the need for general anaesthesia. The use of intra-arterial stents in the treatment of hepatic artery aneurysms has, to our knowledge, not been previously described in the medical literature and represents a promising new approach to the management of these difficult lesions. CONCLUSIONS
Radiological management of hepatic artery aneurysms have obvious advantages over surgery. The avoidance of general anaesthesia and less iatrogenic trauma should result in shorter hospital stays. Endovascular stenting or embolization of the aneurysm lumen are the preferred approaches to extrahepatic hepatic artery aneurysms with the site and morphology of the lesion determining the specific technique. In patients presenting acutely, embolization of either the common hepatic artery, the aneurysm itself or the feeding vessel are possible therapeutic options, all of which compare favorably to surgery which carries a high mortality.
REFERENCES
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3 Jonsson K, Bjernstad A, Eriksson B. Treatment of a hepatic artery aneurysm by coil occlusion of the hepatic artery. Amerieal Journal o f Roentgenology 1980;134:1245-1247. 4 0 k a z a k i M, Higashihara H, Ono H et al. Percutaneous embolization of ruptured splanchnic artery pseudoaneurysms. Acta Radiology 1991;32:349-354. 5 Uflacker R. Transcatheter embolization of arterial aneurysms. British Journal of Radiology 1986;59:317-324. 6 Baker KS, Tisnado J, Cho SR et al. Splanchnic artery aneurysms and pseudoaneurysms: transcatheter embolization. Radiology 1987;163:135-139. 7 Salam TA, Lumsden AB, Martin LG et al. Nonoperative management of visceral aneurysms and pseudoaneurysms. American JournalofSurgery 1992;164:215 219. 8 Countryman D, Norwood S, Register D et al. Hepatic artery aneurysm. Report of an unusual case and review of the literature. American Surgeon 1983;49:51-54. 9 Kibbler CC, Cohen DL, Cruicshank JK et al. Use of CAT scanning in the diagnosis and management of hepatic artery aneurysm. Gut 1985;26:752-756. 10 Harlaftis NN, AKkin JT Hemobilia from ruptured hepatic artery aneurysm. American Journal of Surgery 1977;133:229-232. 11 Gryboski JD, Clemett A. Congenital hepatic artery aneurysm with superior mesenteric artery insufficiency: a steal syndrome. Pediatics 1967;39:344-347. 12 Rieser R, Hauger W. Aneurysm of the proper hepatic artery as a cause of abdominal angina. (in German). Rontgen-Blatter 1988;41:366-368. 13 Bengrnark S, Rosengren K. Angiographic study of the collateral circulation to the liver after ligation of the hepatic artery in man. American Journal o f Surgery 1970;119:620-624. 14 Michels NA. Newer anatomy of the liver and its varient blood supply and collateral circulation. American Journal o f Surgery 1966;112:337-347. 15 Koehler RE, Korobkin M, Lewis F. Arteriographic demonstration of collateral arterial supply ot the liver after hepatic ligation. Radiology 1975;117:49-54. 16 Psathakis D, Muller G Noah M e t al. Present management of hepatic artery aneurysms. Symptomatic left hepatic artery aneurysm; fight hepatic artery aneurysm with erosion into the gallblader and simultaneous colocholecystic fistula - a report of two unusual cases and the current state of etiology, diagnosis, histology and treatment. Vase-Journal o f Vascular Diseases 1992;21:210-215. 17 Tsai CH, Mo LR, Chiou CY et al. Therapeutic embolization of post-cholecystectomy hepatic artery aneurysm. Hepato-Gastroenterology 1992;39:158 160. 18 Goldblatt M, Goldin AR, Schaff MI. Percutaneous embolization for the management of hepatic artery aneurysms. Gastroenterology 1977;73:1142-1146. 19 Sutton D, Lawton G. Angiographic diagnosis of aneurysms involving the hepitoc artery. Clinical Radiology 1973;24:43-48. 20 Lina JR, Jacques P, Mandell V. Aneurysm rupture secondary to transcatheter embolization. American Journal of Roentgenology 1979;132:553-556. 21 Strecker EP, Liermann D, Barth KH et al. Expandible tubular stents for the tratment of arterial occlusive diseases: Experimental and clinical results. Radiology 1990; 175:97-102. 22 Althoff M, Schulte E, Ranft J et al. Occlusion of peripheral aneurysms by arterial stent implantation in inoperable patients a methodologic alternative? (in German). Vasa Suppl. 1992;35:184185.
9 1995 The Royal College of Radiologists, ClinicalRadiology, 50, 792-796.