Monbaliu Diethard R, Debbaut Charlotte, Hillewaert Wim J, Laleman Wim J, Sainz-Barriga Mauricio, Pirenne Jacques, Segers Patrick
Abdominal Transplant Surgery and Hepatology, University Hospitals Leuven, Leuven, Belgium.
Int J Artif Organs. 2012 Feb;35(2):119-31. doi: 10.5301/ijao.5000038.
Hypothermic machine perfusion (HMP) is regarded as a better preservation method for donor livers than cold storage. During HMP, livers are perfused through the inlet blood vessels, namely the hepatic artery (HA) and the portal vein (PV). In previous HMP feasibility studies of porcine and human livers, we observed that the PV flow decreased while the HA flow increased. This flow competition restored either spontaneously or by lowering the HA pressure (PHA). Since this phenomenon had never been observed before and because it affects the HMP stability, it is essential to gain more insight into the determinants of flow competition. To this end, we investigated the influence of the HMP boundary conditions on liver flows during controlled experiments. This paper presents the flow effects induced by increasing PHA and by obstructing the outlet blood vessel, which is the vena cava inferior (VCI). Flow competition was evoked by increasing PHA to 55-70 mmHg, as well as by obstructing the VCI. Remarkably, a severe obstruction resulted in a repetitive and alternating tradeoff between the HA and PV flows. These phenomena could be related to intra-sinusoidal pressure alterations. Consequently, a higher PHA is most likely transmitted to the sinusoidal level. This increased sinusoidal pressure reduces the pressure drop between the PV and the sinusoids, leading to a decreased PV perfusion. Flow competition has not been encountered or evoked under physiological conditions and should be taken into account for the design of liver HMP protocols. Nevertheless, more research is necessary to determine the optimal parameters for stable HMP.
低温机器灌注（HMP）被认为是一种比冷藏更好的供肝保存方法。在HMP过程中，肝脏通过入血管进行灌注，即肝动脉（HA）和门静脉（PV）。在之前对猪和人类肝脏的HMP可行性研究中，我们观察到门静脉血流减少而肝动脉血流增加。这种血流竞争要么自发恢复，要么通过降低肝动脉压力（PHA）来恢复。由于这种现象以前从未被观察到，并且因为它影响HMP的稳定性，所以有必要更深入地了解血流竞争的决定因素。为此，我们在对照实验中研究了HMP边界条件对肝脏血流的影响。本文介绍了通过增加PHA和阻塞出血管（即下腔静脉，VCI）所引起的血流效应。通过将PHA增加到55 - 70 mmHg以及阻塞VCI来引发血流竞争。值得注意的是，严重阻塞导致肝动脉和门静脉血流之间出现重复且交替的权衡。这些现象可能与肝血窦内压力变化有关。因此，较高的PHA很可能传递到肝血窦水平。这种增加的肝血窦压力降低了门静脉和肝血窦之间的压力降，导致门静脉灌注减少。在生理条件下尚未遇到或引发血流竞争，在设计肝脏HMP方案时应予以考虑。然而，需要更多的研究来确定稳定HMP的最佳参数。
