Flow and Pressure during Liver Preservation under ex situ and in situ Perfusion with University of Wisconsin Solution and Histidine-Tryptophan-Ketoglutarate Solution

Abstract

Effective preservation of liver grafts is the first essential step for successful liver transplantation. Insufficient perfusion leads to ischemic-type biliary lesions after transplantation. Perfusion of the graft can be performed either in situ or ex situ, with gravity flow or pressure-controlled. Mainly University of Wisconsin (UW) and histidine-tryptophan-ketoglutarate (HTK) solutions are used widespread in clinical liver transplantation. Due to a persistent lack of data, we performed this systematic investigation of in situ and ex situ perfusion of liver grafts with HTK (low-viscous) and UW (high-viscous) solutions at different pressure steps on the perfusion solution (gravity flow, 50, 100, 150, and 200 mm Hg). End points were perfusion flow and pressure in the hepatic artery. A pig model was used with n = 8 pigs randomized to each (HTK and UW) group. In situ perfusion was ineffective for both solutions at any pressure on the perfusate bag. Ex situ perfusion showed significantly improved flow and pressure in the hepatic artery and, therefore, was highly effective. No major differences between HTK and UW solutions could be detected. Therefore, an additional ex situ perfusion of the hepatic artery should be mandatory in every liver procurement.

Liver Preservation by Aortic Perfusion Alone Compared With Preservation by Aortic Perfusion and Additional Arterial Ex Situ Back-Table Perfusion With Histidine-Tryptophan-Ketoglutarate Solution: A Prospective, Randomized, Controlled, Multicenter Study

“…Hemodynamic measurements corroborated this explanation, as the amount of perfusate reaching the hepatic artery during aortic perfusion proved to be negligible. 39 This shortcoming of SAP may lead to inadequate protection of the bile duct vasculature during cold storage. In view of this theory, our former results 36 demonstrating a reduction in the incidence of ITBLs from 16% (SAP) to 2% (SAP + BP) appeared reasonable.…”

“…However, it appears highly improbable that the different viscosity of the preservation solutions (University of Wisconsin solution versus HTK) could have accounted for the negative results observed in the present study, because animal experiments indicated that arterial flow rates are not significantly affected by the viscosity of the solution used for SAP and BP. 39 The volume of perfusate used for BP may also play a role. Nevertheless, in the former 36 as well as in the present study, BP was performed with 300 mL of the respective solution.…”

Comparative analysis of in situ versus ex situ perfusion on flow and microcirculation in kidney procurement: research on a porcine model

“…In order to align the conditions to those of prior experiments on the porcine liver, presented by our group [5], perfusion of kidney grafts was carried out using histidine–tryptophan–ketoglutarate (HTK). One kidney was perfused in situ via the aorta, whereas the second kidney received sole ex situ perfusion via the RA.…”

“…For volume substitution, Ringer’s solution at 10 ml/kg was constantly administered during the operation. The experimental procedure was kept constant throughout the set of experiments as described previously by our group [5]. …”

“…As described above, the pressure on the preservation solution was increased stepwise, adding pressure to the solution bag using a pressure gauge. The following pressure intervals were taken into account: gravity flow (100 mmHg), +50 (150 mmHg), +100 (200 mmHg), +150 (250 mmHg) and +200 (300 mmHg), as described previously by our group [5]. Subsequent to in situ perfusion, 100 ml NaCl containing a constant amount of 2 ml red-coloured MPs were infused at gravity flow.…”