Abernethy Malformations: Evaluation and Management of Congenital Portosystemic Shunts

Purpose: To assess the utility of preoperative venography in evaluating and managing patients with congenital portosystemic shunts (CPSSs). Materials and Methods: A retrospective study was performed of 42 patients (62% female; median age, 4.1 years) diagnosed with a CPSS from 2005 to 2018. Preoperative venography (n = 39) and balloon occlusive pressure measurements (n = 33) within the mesenteric venous system guided treatment. Primary outcome was serum ammonia levels at 1 month after shunt closure. Management strategies included single (n = 12) or staged (n = 18) operative ligation, endovascular occlusion (n = 8), combined surgical and endovascular closure (n = 2), and observation (n = 2). Results: At 1 month, serum ammonia levels decreased from 82.5 ± 10.3 μmol/L to 38.4 ± 4.6 μmol/L (P < .001). No difference was observed in the decrease between patients treated surgically or endovascularly (P = .91). Mean occluded to non-occluded pressure gradients were significantly lower for endovascular closure (5.3 ± 1.8 mmHg) than for surgical closure (12.3 ± 3.3 mmHg, P = .02). Shunts were classified as extrahepatic in 29 patients and as intrahepatic in 13 patients; all shunts demonstrated filling of the portal system with occlusive venography. Broad and short shunts were closed surgically; narrow and long shunts were closed endovascularly. Shunts were closed in a single session (n = 20) if the pressure gradient was less than 10 mmHg and the occluded mesenteric pressure was less than 25 mmHg. Conclusions: Preoperative venography delineates shunt morphology, and balloon occlusion simulates closure hemodynamics. This information is necessary to determine whether definitive closure should be performed through endovascular or surgical methods and whether closure should be performed in a single or staged setting.