JOURNAL OF THE LOUISIANA STATE MEDICAL SOCIETY
A repeat laparotomy was then performed on day four when the transected right hepatic artery was ligated and a right trisegmentectomy was performed as there was no flow in the right portal vein after the ligation of the right hepatic artery, which would predispose the patient to liver necrosis. Patient tolerated the surgeries well, but was later found to have developed a right subphrenic abscess which was treated with percutaneous drainage on day 14. A right ureteric stent was also placed for the right renal injury on day 10 and a tracheotomy was performed on day 25 due to prolonged intubation. Patient continues to recover without any further complications, at the time of writing of this manuscript.
month. Large, central APFs (Type 2) can be intrahepatic or extrahepatic and are often caused by abdominal trauma and erosion of a splenic artery aneurysm into the portal system. They can cause increased portal venous pressure with enough flow and thus require treatment by transcatheter embolization with surgical approach reserved only for complex cases. Congenital APFs (Type 3) tend to be diffuse and intrahepatic and difficult to manage, requiring varying transcatheter and often surgical treatments.8 Digital subtraction angiography is the gold standard in the diagnosis, treatment planning, and follow-up of APFs. APFs were treated with surgical ligation of the supplying artery in the past, however, endovascular transcatheter arterial embolization is now the treatment of choice. Embolization is directed towards selective closure of the fistula and preservation of adjacent normal vasculature.9 Various embolization agents have been used such as: stainless-steel coils, detachable balloons, onyx, and cyanoacrylate glue.10 Our patient developed the APF due to a gunshot injury to the liver, leading to a communication between the right hepatic artery and the right branch of portal vein. The fistula developed because of direct injury to the right branch of portal vein and the right hepatic artery. The right branch of the portal vein was supplied only by the fistula without any portal venous perfusion. The ligation of the transected right hepatic artery would have caused liver necrosis, so a right hepatic trisegmentectomy was performed to treat this large APF.
DISCUSSION
Hepatic arterioportal fistulas (APF) are the most common intrahepatic vascular shunts, consisting of a communication between a hepatic arterial branch and a portal venous branch. The most common causes of hepatic APFs are trauma, interventional procedures, and vascular malformations.1 Spontaneous small arterioportal shunts may be associated with hepatocellular carcinoma and hemangiomas.2 In a series by Vauthey et al., trauma as the most common cause accounted for 28%, interventional procedures 16%, congenital vascular malformations 15%, tumor 15%, and aneurysm 14% of all reviewed cases.1 APF exposes the portal vascular bed to high arterial pressures and this also leads to interruption of the portal venous flow, which causes portal hypertension and its complications, if not treated early. The common presentations of symptomatic intrahepatic APFs include gastrointestinal bleeding, ascites, congestive heart failure, abdominal pain, and diarrhea.1 The first case of APF secondary to liver biopsy was reported by Preger in 1967.5 APFs after liver biopsy have been reported with a frequency of about 5.4-10 %. Most resolve spontaneously within 12 weeks as they are small and peripheral. Rarely they may be centrally located and grow, leading to clinical symptoms development.6 Doppler ultrasound is typically employed as an initial screen, with high-flow velocities and arterial waveforms in the portal vein. Turbulence with reversal of flow may also be present in the portal vein. Cross sectional imaging using dynamic contrast enhanced CT and MRI can diagnose and characterize APFs. Due to the fistula, there is an early increased attenuation of a peripheral and central portal vein compared with the main portal vein, and “double- barrel” or “rail-tract” signs. A segmental area of transient hepatic enhancement is seen during the arterial phase as a wedge- shaped geographic area of hyperenhancement, due to high- pressure arterial blood passing into a low-pressure portal vein branch.2-4,7 Guzman et al. introduced a classification system for APFwith therapeutic implications. Small, peripheral, intrahepatic APFs (Type 1) with minimal physiologic consequences are most commonly caused by percutaneous liver biopsies. They usually resolve spontaneously and thus can be observed with ultrasound imaging, as they tend to thrombose within one
CONCLUSION
We describe a case of a large APF secondary to gunshot injury, CT and DSA imaging features of this rare pathology, and subsequent surgical treatment. DSA is the gold standard in the diagnosis and treatment, but surgery may be needed for large hepatic arterio-fistulas.
90 La State Med Soc VOL 170 MAY/JUNE 2018
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