A Rare Case of Superior Mesenteric Arterio-venous Fistula Causing Jejunal Varices and Recurrent GI Bleeding
Article Outline
Superior mesenteric arterio-venous (SMA-V) fistulas are rare. They are usually associated with penetrating abdominal trauma or gastrointestinal surgery. We report a patient, who presented with recurrent mild gastrointestinal bleeding and severe abdominal distension for 3 months after a small bowel resection for acute abdomen. A machinery-type bruit was audible in the epigastrium. Oesophageal varices were seen on a gastroscopy. A SMA-V fistula was diagnosed on an angiogram after a large mesenteric vein was seen on CT. The patient had a successful laparotomy with ligation of feeding artery and surgical resection of involved small bowel. A literature review of SMA-V fistulas is discussed.
Keywords: Superior mesenteric arterio-venous fistula, Portal hypertension
Abbreviations: PV, Portal vein, SMV, Superior mesenteric vein, SMA, Superior mesenteric artery, CT, Celiac trunk
Introduction
Superior mesenteric arterio-venous (SMA-V) fistulae are rare. They are usually associated with penetrating abdominal trauma or gastrointestinal surgery. We report a patient who presented with recurrent mild gastrointestinal bleeding and severe abdominal distension for 3 months after a small bowel resection for acute abdomen.
Case Report
A 43-year-old woman presented with recurrent gastrointestinal bleeding and severe ascites. Her previous medical history was remarkable for blunt trauma to the right upper hypochondrium one year earlier, and a small bowel resection for acute abdomen due to a volvulus three months earlier.
Clinical examination revealed a pale, undernourished woman without any stigmata of chronic liver disease. There were multiple abdominal scars from previous laparatomies. There was mild epigastric tenderness.
There was a palpable pulsatile epigastric mass with a machinery-type bruit. Hepatomegaly became obvious only after 4000
ml ascites was drained. Stools were melenous.
The haemoglobin level at the time of admission was 12.0g/dL. The liver function test showed moderate derangement. She was hyponatremic and hypochloremicl: 112.0 and 91.0mmol/L respectively.
Endoscopic examination revealed esophageal varices. Colonoscopy showed diffusely edematous mucosa with punctuate areas of erythema in the entire colon and visualized small bowel.
Computed tomography (CT) angiography of the abdomen revealed diffuse thickening of the small and large bowel along with a large aneurysmal dilatation of the superior mesenteric vein (SMV) measuring 3.2cm in diameter and a severely dilated portal vein (PV) measuring 2.5cm in diameter (Fig. 1).
Fig. 1
A 3-Dreconstruction of the aneurysmal dilation of PV and SMV.
The abdominal aortic angiogram confirmed the existence of an arterio-venous fistula between the superior mesenteric artery (SMA) and SMV. A selective superior mesenteric angiogram revealed two jejunal branches to be the main feeders, one supplying large jejunal varices, and the other representing a fistulous communication to a severely dilated jejunal vein and further to a dilated SMV. There was an abnormal early contrast opacification of the portal system including the dilated portal vein. The branches of SMA, distal to the arterio-venous fistula were not opacified (Fig. 2).
Fig. 2
A selective angiogram of SMA showing two main feeding arteries, one for severe jejunal varices, and one for a fistulous communication via a extremely dilated tumor-like jejunal vein to SMV.
On the following day several episodes of massive hematemesis and hematochezia led to hypotension and loss of consciousness. The patient was intubated and resuscitated. Emergent upper endoscopy revealed esophageal varices and red blood in the stomach without evidence of active bleeding. Emergency laparatomy was performed. The SMA branch, which was feeding the arterio-venous fistula, was identified and ligated with a visible collapse of the dilated SMV. Some 40cm of the small bowel was also resected for ischemia of bowel after ligation of the SMA branch.
The post operative course of this patient was uneventfully. No recurrence of bleeding has occurred with follow-up of 3 month. A postoperative upper gastrointestinal endoscopy revealed almost complete resolution of the esophageal varices 1 month postoperatively. Unfortunately, this patient died from intracranial hemorrhage due to hypertension 4 months postoperatively.
Discussion
Superior mesenteric A-V fistulae have been rarely reported in the medical literature. The patients may present with an abdominal pain, nausea, vomiting, diarrhoea, or bleeding from varices. Clinical findings are few with abdominal bruits and ascites being the most common.1
Since the first report by Mobitz and Finnel in 1960, only 32 cases of late postoperative, iatrogenic superior mesenteric A-V fistula have been documented (present case included), and summarized in Table 1.2, 3
Table 1. Etiologies of iatrogenic superior mesenteric A-V fistula
| Case number | |
|---|---|
| Bowel resection | 22 |
| Gastrectomy | 2 |
| Division of adhesion | 2 |
| Appendectomy | 2 |
| After kidney-pancreatic transplantation | 2 |
| Aortobifemeral bypass | 1 |
| Pancreatic head resection | 1 |
In addition, suture material near the site of fistula had been reported in several cases of SMA to SMV fistula, suggesting that the fistula can be related to a transfixation suture that passes through artery and vein simultaneously.3
To establish the diagnosis of the superior mesenteric A-V fistula, abdominal ultrasound may be helpful. However, CT-angiography with its capacity for reformatting the vessel anatomy provides the definitive diagnosis. Selective superior mesenteric angiography may be necessary to identify the specific feeding vessels to the fistula. The most common feature on CT-angiography and DSA are a large aneurysmal dilatation of SMV, and a severely dilated portal vein. In addition, in DSA there is an abnormal early filling of SMV and PV with no opacification of SMA branches distal to the A-V fistula.
Treatment of superior mesenteric A-V fistulae is either surgical ligation with or without removal of the affected organ, or interventional radiology, using percutaneous embolization of the feeding vessel with coils. Both options have had favorable results in the literature, and there is no current standard recommendation for one over the other.1, 2, 3, 4 However, we still have the third option that is the use of stent-graft occluding the feeding vessels while maintaining the patency of SMA, which may be more optimal for the patient with SMA-V fistula.
Surgery clearly carries more immediate procedural risk, such as intraoperative bleeding, whereas embolization may result in occlusion of a critical vessel supplying the small intestine, possibly resulting in ischemia, but the risk is minimal for the patient with SMA-V fistula.
In our patient we elected to use laparatomy which allowed us to inspect the intestine with a subsequent resection of the small bowel deemed necessary because of ischemic.
The objective of the operation was to control the bleeding from the jejunal varices and reduce the portal venous pressure while preserving the liver function. This was achieved by ligation of the feeding artery without affecting the venous drainage of the alimentary tract.
In conclusion treatment of symptomatic A-V fistula requires a definitive diagnosis using CT-angiography, and can be managed either endovascularly or using open surgery, or both.
References
- . Superior mesenteric arteriovenous fistula presenting 10 years after extensive small bowel resection. Aust N Z J Surg. 2000;70:822–823
- . A rare case of jejunal arterio-venous fistula: treatment with superselective catheter embolization with a tracker-18 catheter and microcoils. Cardiovasc Intervent Radiol. 2004;27:671–674
- . Superior mesenteric arteriovenous fistula causing massive hematemesis. Surgery. 2003;134:102–104
- . Mesenteric arteriovenous fistula causing jejunal varices and recurrent GI bleeding. Am J Gastroenterol. 2001 Jan;96(1):265–267
PII: S1533-3167(06)00064-1
doi:10.1016/j.ejvsextra.2006.06.001
© 2006 Elsevier Ltd. All rights reserved.
