Split liver transplantation (LT) has been developed to increase organ availability, but it results in prolonged cold ischemia and higher risks of postreperfusion bleeding and ischemia-reperfusion injury (IRI). Therefore, partial liver grafts are considered as marginal grafts. Dynamic preservation strategies have been proposed to minimize IRI and optimize post-LT outcomes, especially for extended criteria donor livers; however, all current trials assessing liver machine perfusion exclude partial grafts.1 For instance, our team is currently conducting a multicenter randomized trial assessing end-ischemic hypothermic oxygenated perfusion (HOPE) before LT with extended criteria donor grafts (NCT03929523), with the exclusion of partial grafts.
We herein report an original 2-step technique of ex vivo left lateral/right extended graft splitting with concurrent HOPE: first, vessel dissection and hilar plate division are facilitated by the “star exposure” and performed during static cold storage; second, parenchymal transection is performed with simultaneous HOPE using a “split hanging maneuver” (Figure 1). After approval by the institutional ethics committee (CSE-HCL_21_202), we applied this novel approach for 2 livers, allowing us to successfully transplant 2 adults (aged 56 and 45 y) and 2 pediatric recipients (aged 36 and 5 mo, weighting 15 and 5 kg, respectively). All 4 recipients showed satisfactory allograft function recovery. The 36-mo-old child had a history of previous LT for Alagille syndrome, which complicated with hepatic artery thrombosis and ischemic cholangiopathy. He was retransplanted using the present technique in a context of marked hemodynamic instability; despite 2 relaparotomies for postoperative hemorrhage, he recovered and normalized factor V on posttransplant day 6. The 3 other recipients normalized their factor V between posttransplant day 1 and 3, which is quite remarkable compared to our experience of ex vivo split LT without HOPE.
Ex vivo splitting with concurrent dynamic preservation represents a technical challenge, with very limited data available. Its feasibility has been suggested on discarded livers with normothermic perfusion,2,3 on swine using dual hypothermic perfusion,4 and during dual-HOPE.5,6 We herein report the 2 first cases of LT using concurrent liver splitting and HOPE through the portal vein only, which, according to us, represents the least demanding and most secure machine perfusion modality for ex vivo splitting. The graft is preserved in the cold during the entire procedure, which reduces the risk of warm ischemia due to technical problems or cannula kinking. In comparison with the report by Thorne et al,6 who perfused the graft in a supine position during both vascular dissection and parenchymal transection, our 2-step technique has the advantage of allowing bench top cholangiography, which is not currently possible after initiation of HOPE. Moreover, the split hanging maneuver in prone position allows performing parenchymal transection through an anterior approach, similarly to elective hepatectomies.
Of note, single perfusion through the portal vein facilitates the procedure and avoids arterial injury during graft handling, without compromising the protective effect of HOPE against IRI. This strategy allows to extend perfusion of both partial grafts through a single portal cannula, for example in case of a difficult recipient hepatectomy. Finally, although sequential perfusion of the 2 grafts after splitting may be easier, simultaneous splitting and perfusion enable the performance of parenchymal transection during HOPE, which hereby reduces graft rewarming caused by graft mobilization out of ice and heat exposure by the energy transection device. Further studies are needed to assess this promising dynamic preservation strategy, which may improve the outcome of split LT.
1. Muller X, Mohkam K, Mueller M, et al. Hypothermic oxygenated perfusion versus normothermic regional perfusion in liver transplantation from controlled donation after circulatory death: first international comparative study. Ann Surg. 2020;272:751–758.
2. Brockmann JG, Vogel T, Coussios C, et al. Liver splitting during normothermic organ preservation. Liver Transpl. 2017;23:701–706.
3. Stephenson BTF, Bonney GK, Laing RW, et al. Proof of concept: liver splitting during normothermic machine perfusion. J Surg Case Rep. 2018;2018:rjx218.
4. Ishii D, Matsuno N, Gochi M, et al. Applicability of hypothermic oxygenate machine perfusion preservation for split-liver transplantation in a porcine model: an experimental study. Ann Transplant. 2020;25:e919920.
5. Spada M, Angelico R, Grimaldi C, et al. The new horizon of split-liver transplantation: ex situ liver splitting during hypothermic oxygenated machine perfusion. Liver Transpl. 2020;26:1363–1367.
6. Thorne AM, Lantinga V, Bodewes S, et al. Ex situ dual hypothermic oxygenated machine perfusion for human split liver transplantation. Transplant Direct. 2021;7:e666.