Impact of mesocaval shunt on safe minimal liver remnant: Porcine model

AIM: To investigate the capacity of shunts to relieve portal hypertension and decrease the safe minimal liver remnant in pigs. METHODS: A subtotal hepatectomy with < 60 mL blood loss and without hepatic pedicle occlusion was performed. The mesenteric venous inflow was diverted through a mesocaval shunt (MCS) constructed using the prepared left renal vein with an end-to-side running suture of 5-0 proline. All 21 animals that underwent subtotal hepatectomy and/or MCS were divided into three groups. In the 15% group, the residual volume was 14%-19% of total liver volume (TLV); in the 15%+ S group, the residual volume was also 14%-19% of TLV with a mesocaval shunt (MCS); and in the 10%+ S group, the residual volume was 8%-13% of TLV with an MCS. In the three groups, the intraoperative portal vein pressure (PVP) and portal vein flow (PVF) were monitored and compared at laparotomy and 1 h post-hepatectomy. The survival rate, sinusoidal endothelial damage, tissue analysis, and serum analysis were investigated among the three groups. RESULTS: The percentage residual liver volume was 15.9%, 16.1% and 11.8% in the 15%, 15%+ S, 10%+ S groups, respectively. After hepatectomy, PVF and portal-to-arterial flow ratio in the 15%+ S group significantly decreased and hepatic artery flow (HAF) per unit volume significantly increased, compared to those in the 15% group. The PVP in the 15%+ S group and 10%+ S group increased slightly from that measured at laparotomy; however, in the 15% group, the PVP increased immediately and significantly above that observed in the other two groups. The 14-d survival rates were 28.5%, 85.6%, and 14.2% in the 15%, 15%+ S, and 10%+ S groups, respectively. In the 15%+ S group, the shunts effectively attenuated injury to the sinusoidal endothelium, and the changes in the serum and tissue analysis results were significantly reduced compared to those in the 15% and 10%+ S groups. CONCLUSION: MCS can decompress the portal vein and so attenuate liver injury from hyperperfusion, and make extreme or marginal hepatectomy safer.