小肝移植物与小肝综合征

小肝移植物和小肝综合征是限制成人活体肝移植进一步应用的重要因素。小肝移植物是指移植物与受者质量比小于0.8%或移植物体积与受者标准肝体积比小于40%。小肝综合征是指移植物不能满足受者的功能需要,引起肝功能障碍,包括凝血病、腹水、长期胆汁淤积和脑病,甚至伴有肺功能衰竭和肾功能衰竭,如果不行再次肝移植常会导致受者死亡。小肝综合征的发生与多种因素有关,如移植物大小、潜在病变、再生能力、流入道、流出道情况,受者病情轻重等。门静脉过度灌注、静脉病变、肝动脉缓冲效应在小肝综合征早期和晚期的临床和组织病理学表现中起重要作用。小肝综合征的防治措施,主要集中在两个方面:选择更大的移植物和进行门静脉压力和血流的调控。门静脉压力和血流的调控,可能是成功采用更小移植物进行成人活体肝移植的关键所在。

Small-for-size graft and small-for-size syndrome

Small-for-size grafts and small-for-size syndrome remain the greatest limiting factor for the expansion of living donor liver transplantation. Graft to recipient weight ratio less than 0.8% or the ratio of graft volume to standard liver volume of the recipient less than 40% is termed as small-for-size graft. A partial liver graft unable to meet the functional demands of the recipient results in liver failure characterized by development of coagulopathy, ascites, prolonged cholestasis and encephalopathy, often associated with pulmonary and renal failure, and frequently leads to death of the recipient in the absence of re-transplantation. This ill-defined clinical picture is termed “small-for-size syndrome”. The pathogenesis of small-for-size syndrome is related to graft size, underlying liver disease, regenerative response, vascular inflow and outflow, and recipient’s health status. Portal hypertension, venous pathology, and the arterial buffer response importantly contribute to early and late clinical and histopathologic manifestations of the small-for-size syndrome. The strategies to prevent and treat small-for-size syndrome include using larger graft and modulation of portal pressure and portal inflow. Modulation of portal inflow seems to be the key for successful adult living donor liver transplantation with smaller grafts.