Portal hypertension caused by postoperative superior mesenteric arteriovenous fistula

Introduction. Arteriovenous fistula of the superior mesenteric blood vessels is a rare complicaton in abdominal surgery. Case report. We presented a 49-year-old man with cramplike abdominal pain, abdominal distension and weight loss symptoms, with a history of previous small bowel resection and right colectomy, due to Crohn disease, 16 years ago. Clinical examination revealed a paraumbilical pulsation with systolic murmur and thrill. Ultrasonography and computed tomography revealed cystic dilatation of the superior mesenteric vein, hepatomegaly and ascites. Upper endoscopy revealed grade I esophageal varices with portal hypertensive gastropathy. The diagnosis of arteriovenous fistula between superior mesenteric artery and vein was confirmed by angiogram of the superior mesenteric vessels and resection of the fistula was performed. Control examination after nine months showed no signs of portal hypertension. Conclusion. Early diagnosis and treatment of mesenteric blood vessel arteriovenous fistula prevents portal hypertension development and its complications.


Introduction
Arteriovenous fistula (AVF) affecting superior mesenteric vessels are uncommon, and have usually been observed in patients who have undergone abdominal surgery or have abdominal trauma [1][2][3][4][5][6][7] .Due to localisation in the portal circulation, it increses blood flow in the portal vein and may produce portal hypertension with its complications.We presented a patient with superior mesenteric AVF, which devel-oped 16 years after small bowel resection and right colectomy.

Case report
A 49-year-old-male patient was admited to our hospital due to cramp-like abdominal pain, abdominal dystension, malaise, fatigue and weight loss of 8 kg for one month.Symptoms appeared one month before admission.Sixteen Popovi DjD.Vojnosanit Pregl 2012; 69 (7): 623-626.years ago, the patient had small bowel resection and right colectomy for ileus caused by ileitis terminalis (Morbus Crohn).He had no complains until the present illness.At physical examination, the patients was subicteric.Abdominal examination revealed a soft, mobile, pulsating mass in the paraumbilical region.The abdominal, systolic murmur was heard and thrill was palpated.Laboratory tests showed elevated leucocyte count 12 × 10 9 /L (4.0-10.0× 10 9 /L), erythrocyte sedimentation rate 32 mm/h (2-10 mm/h), fibrinogen 7.9 g/L (2-4 g/L), total bilirubin 28.7 μmol/L (3-22 μmol/L), conjugated bilirubin 15.5 μmol/L (0-7 μmol/L), aspartate aminotransferase 155 U/L (14-50 U/L), alanine aminotransferase 477 U/L (21-72 U/L), alkaline phosphatase 310 U/L (38-126 U/L) and gamma-glutamyl transpeptidase 287 U/L (8-78 U/L).Other biochemical parameters were within the reference range.Other causes of liver diseases were excluded (no history of alcohol consumption, negative viral markers, autoantibodies and laboratory tests for metabolic diseases).Ultrasonography and computed tomography (CT) of the abdomen showed hepatomegaly, ascites around the liver and a small polyp in the gallbladder.The superior mesenteric vein (VMS) was dilated, aneurismatic (8 × 5 × 12 cm) (Figure 1).Doppler ultrasonography revealed dilatation of portal vein (28 mm) with hyperkinetic flow (v = 31 cm/s).The lienal vein was considered normal, as well as diameter and its flow.Upper endoscopy revealed grade I esophageal varices without "red cherry spots".Portal hypertensive gastropathy also often described as snake-skin appearance was detected in the fornix and corpus of the stomach.Colonoscopy did not detect recidive of Crohn`s disease.Selective arteriography of the superior mesenteric artery (AMS) demonstrated dilatation of AMS, aneurismatic dilatation of VMS and its early filling directly from the AMS (Figure 2).Midline laparotomy was performed.Fistulous communication between the AMS and VMS was demonstrated (Figure 3).An AVF had a thick wall and external appearance of the

Discussion
Portal hypertension is characterized by an increase in portal vein pressure as a result of impediment to portal flow 8 .According to the level of impediment it may be prehepatic, intrahepatic and posthepatic.AVF is a patological, direct communication between an artery and a vein, when blood bypasses a capilary bed.An AVF may be congenital or acquired: congenital one is a result of persistent embryonic blood vessels that fail to differentiate into arteries and veins 9 , while an acquired occurs as a consequence of surgery or injures [9][10][11][12] .AVF of the superior mesenteric blood vessels is a rare complication of abdominal surgery.The first case was described in 1960 by Movitz and Finne 13 .Delays in diagnosis after surgery have been reported up to 20 years 14 .In case of our patient, the AVF became symptomatic 16 years after the surgery.Clinical presentation varies from asymptomatic to manifest, most commonly as cramping abdominal pain with or without diarrhea 3,7,12,15,16 .Pain is a result of ischemic bowel, as blood is "stolen" by the portal system leaving the segment distal to the fistula with a compromised arterial circulation.Diarrhea is probably related to impaired perfusion of the mucosa 17 .Portal hypertension, congestive heart failure, or gastrointestinal tract hemorrhage have also been reported 14,15,[17][18][19][20][21] .In the presented patient, the first symptoms were abdominal dystension and cramp-like abdominal pain, as a result of portal hypertension.Clinical examination is performed to detect paraumbilical pulsation and systolic murms with thrill, such was in our patient.Abdomi-nal ultrasonography and CT indicate the presence of AVF between AMS and VMS, with portal dilatation vein 3,21 .However, selective arteriography AMS, allows the determination of exact location and extensiveness of AVF.In the presented patient, AVF was diagnosed by ultrasonography and CT of the abdomen, and the diagnosis was confirmed by selective arteriography of AMS.There are two modalities of the therapy: surgery and interventional radiology methods (percutaneous catheter embolisaton) 3-5, 7, 19, 20, 23, 24 .Surgery has traditionally been the method of choice for treating AVF involving superior mesenterial vessels, but significant morbidity and mortality associated with surgical treatment has made interventional radiology methods priority, except in patients with relative or absolute contraindications for surgery 25,26 .The presented patient had achieved complete recovery after operative treatment.Early diagnosis and treatment of mesenteric blood vessel AVF prevents the development of portal hypertension and liver damages with its sequelae of variceal bleeding and ascites 21 .

Conclusion
AVF of the superior mesenteric blood vessels is a rare complicaton of abdominal surgery.This disease should be kept in mind in patients who present with cramping abdominal pain, diarrhea and signs of portal hypertension, who in the past had abdominal surgery or trauma.Early diagnosis and treatment prevents the development of liver and heart damages, with all eventual complications.

Fig. 2 -
Fig. 2 -Selective arteriography of superior mesenteric artery (AMS) demonstrated dilatation of AMS and aneurismatic dilatation of the superior mesenteric vein