Background: After small-for-size graft (SFSG) transplantation, elevated portal venous pressure (PVP) may lead to post-operative liver damage. Herein we evaluated the impact of portocaval shunt (PCS) to control PVP on liver grafts and intestine following SFSG transplantation. Methods: Nineteen SFSG transplantations were performed with 30% of native liver in swine. Swine were divided into 3 groups: a high-flow shunt group (HS: n = 7), in which portal venous flow (PVF) was reduced with a 10-mm diameter PCS; a low-flow shunt group (LS: n = 6), in which PVF was reduced with a 5-mm diameter PCS, and a no-shunt group (NS: n = 6), in which no PCS was placed. Results: Seven-day survivals were 83.3% in NS, 100% in LS and 0% in HS (p = 0.0088). PVP was significantly higher in the NS group (p = 0.0001; mean +/- SEM NS/LS/HS: 20.5 +/- 0.7/14.0 +/- 1.2/11.6 +/- 0.5 mm Hg). The LS group exhibited the highest compliance (PVF/PVP; NS/LS/HS 42.7 +/- 10.9/44.6 +/- 4.9/37.7 +/- 8.3 ml/min/mm Hg; p = 0.009), the lowest aspartate aminotransferase (NS/LS/HS 562 +/- 18/370 +/- 55/720 +/- 130 IU/l; p = 0.0493), and suppressed deleterious alternations of the hepatic parenchyma and intestinal mucosa. Conclusions: Portal hypertension after SFSG transplantation impaired liver and intestinal mucosa; however, inadequate portal flow impaired not only the liver, but also survival. Copyright (C) 2012 S. Karger AG, Basel