Extreme hepatectomy with modified ALPPS in a rat model: gradual portal vein restriction associated with hepatic artery restriction.

ABSTRACT

BACKGROUND & AIM: Associating liver partition and portal vein ligation (PVL) for staged hepatectomy (ALPPS) is a creative strategy for enlarging the future liver remnant (FLR) and increasing the tumor resectability rate. However, the indications for ALPPS must have a certain limit when the FLR is too small. We aimed to establish a modified ALPPS model with more widen applicability in rats. METHODS: An extreme ALPPS model was established in rodents with only a 6.5% FLR. The portal vein (PV) was subjected to restriction to different degrees, then the portal vein pressure (PVP) was measured. Then, different modifications of ALPPS, including hepatic artery restriction (HAR), gradual portal vein restriction (GPVR), and GPVR-associated HAR (HAR+GPVR), were applied in the extreme ALPPS models. RESULTS: PVL or PVR provoked an immediate increase in the PVP. The PVP in the PVR -1.28 mm, PVR -0.81 mm, PVR -0.63 mm, and PVL groups was 11.05±1.57 cmH2O, 16.18±1.92 cmH2O, 20.66±1.99 cmH2O, and 24.10±3.33 cmH2O, respectively, and the corresponding 3-day survival rate was 100%, 90.09%, 36.33% and 0, respectively. Then, in the extreme ALPPS model, the growth ratio of the FLR in the control, HAR, GPVR, and HAR+GPVR groups was 0.43±0.21, 0.50±0.16, 4.80±0.86, and 7.40±2.56, and as a consequence, the corresponding 30-day survival rate was 9.09%, 15.38%, 84.61% and 92.90%, respectively. CONCLUSION: ALPPS itself has a limit, and high PVP after PVL contributes to postoperative death in the extreme ALPPS model. Furthermore, a modified method for extreme ALPPS is proposed, i.e., GPVR+HAR in place of PVL, which significantly improves the survival rate of extreme hepatectomy in rat models.