E xtrahepatic arteriovenous malformations (AVMs) of the gastrointestinal (GI) tract are rare and mostly congenital anomalies. They are usually asymptomatic but may present with portal hypertension in the absence of primary liver pathology. They are also rare causes of massive GI bleeding. Treatment modalities may include ligation of the afferent artery, embolization of feeding vessels, portocaval shunting, or surgical resection of part or all of the affected organ (1).We report a case of a patient with an AVM in the head of the pancreas, which caused massive GI bleeding that recurred after embolization and which was subsequently treated with a pyloruspreserving Whipple pancreaticoduodenectomy. The present case report also highlights the recent developments in the diagnosis and treatment of arterioportal malformations.
CASE prESEntAtionA 45-year-old woman was admitted to our hospital with significant upper GI bleeding. She had no history of liver disease, chronic pancreatitis or alcohol abuse. Upper GI endoscopy showed grade II esophageal and gastric varices. A transjugular liver biopsy was negative for cirrhosis. Celiac arteriography showed a tangle of blood vessels in the region of the head of the pancreas, supplied from branches of the gastroduodenal artery, with early shunting of arterial blood into the portal vein ( Figures 1A and 1B).Subsequent venography demonstrated elevated pressure in the hepatic venous system, with a wedge hepatic vein pressure of 23 mmHg and free hepatic vein pressure of 17 mmHg. This was presumed to be secondary to arteriovenous shunting between the pancreatic branches of the gastroduodenal artery and the portal vein. The patient underwent transcatheter coil embolization of the feeding vessel with relief of symptoms for approximately six months, followed by another episode of GI bleeding. Upper GI endoscopy was repeated and showed grade I esophageal varices. A celiac angiogram showed persistence of the AVM and worsening of portal hypertension, with enlargement of venous collaterals. Re-embolization was not an option at that stage because the gastroduodenal artery had been coil embolized (Figure 2). The patient subsequently underwent a pylorus-preserving Whipple pancreaticoduodenectomy. She recovered uneventfully and has not reported any episodes of GI bleeding since her surgery six years ago.
DiSCUSSionAVMs of the GI tract are uncommon and, when present, may be found in the liver or in extrahepatic locations (2). Meyer et al (3) reviewed a series of GI AVMs and found that 78% of these were located in the cecum and the right colon, followed by 10.5% in the jejunum, 5.5% in the ileum, 2.3% in the duodenum, 1.4% in the stomach and 0.9% in the rectum. Only 0.9% were found in the pancreas. Extrahepatic AVMs have been described, including arterioportal malformations between the accessory right hepatic artery, gastroduodenal artery, or superior mesenteric artery and the portal vein. Ninety per cent of AVMs of the pancreas are congenital in origin and 10% to 30% of them are associated with O...