British Journal of Radiology (2007) 80, e216-e218
© 2007 British Institute of Radiology
doi: 10.1259/bjr/33895565
Post-operative splenic arteriovenous fistula detected with 16-multidetector computed tomography
F Crusco, MD
1
A Antoniella, MD
1
C Puligheddu, MD
1
A Z Fabbri, MD
2 and
A Giovagnoni, MD
3
1 Department of Radiology, AUSL 2 Umbria. Assisi Hospital, via fuori porta nuova, 06081, Assisi, 2 Department of Internal Medicine and Oncological Sciences, University of Perugia and 3 Institute of Radiology, University of Marche, Torrette Hospital, Ancona, Italy
Correspondence: Dr Federico Crusco, Radiology, Assisi Hospital, Via fuori porta nuova, Assisi, 06082, Italy. E-mail: fcrusco{at}sirm.org
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Abstract
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We herein report on a new radiological case of post-operative splenic arteriovenous fistulae (SAVF) with CT-based diagnosis. A brief review of the inherent literature is also discussed.
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Introduction
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Splenic arteriovenous fistulae (SAVF) are considered either congenital or acquired. The former occur more frequently in Ehlers-Danlos and Osler-Weber-Rendau syndromes. Acquired fistulae are commonly post-traumatic, due to blunt abdominal trauma (resulting from the rupture of a pre-existing or a post-traumatic splenic artery aneurysm into an adjacent splenic vein) or penetrating injury producing direct arteriovenous communication. Post-splenectomy SAVF are extremely rare, with less than 10 cases reported in the English literature. This paper discusses, with a brief literature review, the radiological diagnosis and treatment of a case of post-operative SAVF using Doppler ultrasound and CT-based diagnosis.
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Case report
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A 47-year-old woman was admitted with malaise and vague, insidious onset of left quadrant abdominal pain. She gave a history of splenectomy following blunt abdominal trauma 4 years previously. Physical examination showed moderate abdominal distention as well as systolic murmur over the left hypocondrium and epigastrium. She was haemodynamically stable. Laboratory tests showed mild anaemia with a haemoglobin level of 11.8 g dL–1. The patient's serum electrolytes, liver and renal function tests were all within normal limits. Colour Doppler ultrasound (ATL/Philips HDI 5000; Philips Medical Systems, Best, Netherlands), showed a moderately dilated splenic artery with increased diastolic flow and a high velocity jet into the distended splenic vein. The portal vein showed an arterialized hepatopetal flow with a mean velocity of 70 cm s–1.
To verify the suspected SAVF, we performed biphasic abdominal multidetector computed tomography (MDCT), using a 16-row scanner (Philips Brilliance 16; Philips Medical Systems, Best, Netherlands) and a dual-head power injector (Stellant; Medrad), by intravenous administration of 110 mL of low osmolar, non-ionic, high-concentration contrast medium (iomeprol, Iomeron 400; Bracco, Milan, Italy) at a rate of 4 mL s–1. We used a 16x1.5 mm detector configuration and 2 mm thick images reconstructed every 1 mm. An aneurysmal fistolous communication was demonstrated between the distal splenic artery and vein, with marked, opacification of the dilated portal vein during the arterial phase. There were no imaging features of liver parenchymal disease. These findings (Figure 1
) are compatible with the diagnosis of secondary post-splenectomy portal hypertension caused by SAVF. The patient was discharged in good health after a successful transcatheter balloon embolization of the SAVF.
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Figure 1. In this 47-year-old splenectomised woman, (a) axial thick-slab maximum-intensity projections and (b) oblique 3-dimensional volume-rendering images, obtained with 16-detector row CT, show strong and early enhancement of a dilated splenic and main portal vein, approaching the density of the aorta, during the arterial phase. Note the clear depiction of the intrahepatic portal circuit during the arterial phase. The aneurysmal arteriovenous fistula is well demonstrated in the splenic lodge.
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Discussion
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Complications from both open and laparoscopic splenectomy occur in less than 5% of patients. Complications include pneumonia, post-splenectomy sepsis, thrombotic complications, wound infections, haemorrhage, subphrenic abscess, pancreatic abscess or fistula, pancreatic pseudocyst, gastric fistula or perforation, and bowel obstruction caused by scar tissue [1]. Post-operative SAVF is a rare but not insignificant complication of splenectomy, with less than 10 cases described in the English literature. It results from creation of a small intimal communication between the splenic artery and vein, caused by simultaneous surgical ligature of the vessels. Patients with fistulae may be asymptomatic but can present with signs or symptoms of portal hypertension (PH), such as esophageal varices and ascites [2]. Diarrhoea has rarely been reported for a combination of acute portal hypertension and mesenteric ischaemia due to the steal phenomenon [3]. Cardiac symptoms of tachycardia, left ventricular dilatation, and myocardial ischaemia due to a hyperdynamic circulation, have been reported by Gunther [4]. The patient described in our report was hospitalized because of malaise and abdominal pain in the left quadrant; the main clinical finding of the SAVF was a systolic machinery loud bruit in the left hypocondrium and epigastrium. An evaluation of 31 cases of diverse SAVF described in the literature showed that this was the sign most frequently observed (61% of cases) [5]. The cause of the bruit is related to the shunting of blood flow from the high-pressure arterial side to the low-pressure venous side, which creates an abnormal low-resistance circuit with turbulence and dilatation of both the afferent artery and the efferent vein.
A prompt diagnosis of SAVF is necessary in order to establish early treatment and prevent the development of hepatosclerosis or cirrhosis. Until recently, the standard criterion for SAVF diagnosis has been angiography; however, an early diagnosis is now possible using ultrasound and CT examination. When a bruit in the left flank on physical examination is suspected, the Colour Doppler Ultrasound is the first, non-invasive, imaging test performed to characterize the direction and velocity of blood flow and to confirm the diagnosis [6]. Dynamic dual-phase MDCT angiography is the most important modality as it is able to delineate the morphological characteristics, number, location and extent of the arteriovenous connections. As stated in our case, the most common CT angiographic signs are an aneurysmal artery proximal to the fistulous communication, and early and strong contrast enhancement of a dilated adjacent vein during the arterial phase. Moreover, MDCT is the leading imaging modality used to determine preintervention planning. Non-surgical percutaneous interventional radiological techniques, such as the embolization of low-flow fistulae with gel foam/steel coils, and high-flow fistulae with balloons, should be the primary treatment options, reserving the open surgery option for fistulae not amenable to embolization. These fistulae are most commonly associated with a large caliber of forming vessels [7, 8]. In summary, Doppler Ultrasound can help detect SAVF, even without direct demonstration of fistulous communication, by demonstrating the direction and the velocity of blood flow. Contrast-enhanced MDCT angiography provides more detailed morphological information about SAVF and is the method of choice for treatment planning.
Received for publication January 26, 2006.
Revision received May 24, 2006.
Accepted for publication June 14, 2006.
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References
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Abstract
Introduction
