[Experimental study on mechanism of graft injury of small-for-size liver transplantation in miniature pigs].

Objective: To elucidate the mechanisms of graft injury in small-for-size liver transplantation.

Methods: Animal models were established with skeletonized and denervated anatomic parahepatic dissection, hepatectomy and perfusion in situ. Chinese Bama miniature pigs were divided into three groups (n = 5): Group A, liver transplantation; Group B, partial liver transplantation with right hemi-liver graft and Group C, liver transplantation with right median and caudate lobe graft. Animals were followed for 7 days with regards to survival, dynamical portal venous pressure (PVP), portal blood flow (PBF) and graft histopathological examination.

Results: Animal survivals were as follows: Group A, 5/5, Group B, 5/5 and Group C, 1/5. PVP rose immediately after reperfusion. PVP in Group C peaked to 28.6 +/- 2.07 mm Hg. Portal blood flow (PBF) measured by CDFI showed that the index of PBF per gram liver tissue reached 3.56 +/- 0.11 ml x min(-1) x g(-1) at the first hour post-reperfusion in Group C. Hepatic morphological examination showed that severe pathological changes occurred in small-for-size grafts, including sinusoidal congestion, hemorrhage, hepatocytic ballooning change or necrosis, endothelial cell detachment, Disse's space widening or vanishing and significant apoptosis.

Conclusion: Portal over perfusion and acute portal hypertension are the primary etiological mechanisms of graft injury in small-for-size liver transplantation.