Development of a Simple and Active Shunt System in the Anhepatic Stage for Surgical Training of Orthotopic Liver Transplantation.

Background: A pig model has been commonly used for technical training for clinical liver transplantation (LT). However, as the healthy pigs have no shunt bypassing the portal vein (PV), it is necessary to complete LT within 30 minutes after shutting off the PV flow. While a model that uses an ex vivo shunt system has been used to alleviate the constraints of the anhepatic phase, it has been often difficult to keep sufficient blood flow rate and prevent the intestinal congestion because the blood vessels were occluded easily with the suction pressure by using the conventional shunt system.

Methods: We designed a portable shunt system and a novel connector that can prevent the blood vessel from occluding. The system can separately control the flow rate of PV and inferior vena cava (IVC) and detect whether the blood vessels were occluded. By reducing the solution volume in the circuit, the effected blood loss ex vivo could be minimized. The stability of this system was verified with 15 medical doctors in an advanced medical professional education course.

Results: The system enabled the blood flow to maintain ≥ 20 mL/minute and prevented the intestinal congestion. The perioperative hemodynamics of the recipient were stable without a blood transfusion using 25 to 40 kg pigs. We confirmed that all LT training were completed, even 60 minutes after shutting off the PV flow.

Conclusions: Our system greatly contributed to training on LT for conducting the survival experiments.