The Application of Interventional Radiology in Living-Donor Liver Transplantation

Immunomodulatory Role of Mesenchymal Stem Cells in Liver Transplantation: Status and Prospects

BACKGROUND

Liver transplantation (LT) is the only effective therapy for end-stage liver diseases, but some patients usually present with serious infection and immune rejection. Those with immune rejection require long-term administration of immunosuppressants, leading to serious adverse effects. Mesenchymal stem cells (MSCs) have various advantages in immune regulation and are promising drugs most likely to replace immunosuppressants.

SUMMARY

This study summarized the application of MSCs monotherapy, its combination with immunosuppressants, MSCs genetic modification, and MSCs derivative therapy (cell-free therapy) in LT. This may deepen the understanding of immunomodulatory role of MSCs and promote the application of MSCs in immune rejection treatment after LT.

KEY MESSAGES

MSCs could attenuate ischemia-reperfusion injury and immune rejection. There is no consensus on the effects of types and concentrations of immunosuppressants on MSCs. Although genetically modified MSCs have contributed to better outcomes to some extent, the best modification is still unclear. Besides, multiple clinical complications developed frequently after LT. Unfortunately, there are still few studies on the polygenic modification of MSCs for the simultaneous treatment of these complications. Therefore, more studies should be performed to investigate the potency of multi-gene modified MSCs in treating complications after LT. Additionally, MSC derivatives mainly include exosomes, extracellular vesicles, and conditioned medium. Despite therapeutic effects, these three therapies still have some limitations such as heterogeneity between generations and that they cannot be quantified accurately.

Imaging and Intervention in the Management of Vascular Complications Following Liver Transplantation

Liver transplantation is the treatment of choice in majority of the patients with end stage liver disease. Vascular complication following liver transplantation is seen in around 7-13% of the patients and is associated with graft dysfunction and high morbidity and mortality. Early diagnosis and prompt treatment are crucial in management of these patients. Advances in interventional radiology have significantly improved the management of vascular complications using minimally invasive percutaneous approach. Endovascular management is preferred in patients with late hepatic artery thrombosis, or stenosis, whereas retransplantation, surgical revision, or endovascular management can be considered in patients with early hepatic artery thrombosis or stenosis. Hepatic artery pseudoaneurysm, arterioportal fistula, and splenic artery steal syndrome are often treated by endovascular means. Endovascular management is also preferred in patients with symptomatic portal vein stenosis, early portal vein thrombosis, and symptomatic late portal vein thrombosis, whereas surgical revision or retransplantation is preferred in patients with perioperative portal vein thrombosis occurring within 3 days of transplantation. Venoplasty with or without stent placement can be considered in patients with hepatic venous outflow tract or inferior vena cava obstruction. Transjugular intrahepatic portosystemic shunt (TIPS) may be required in transplant recipients who develop cirrhosis, often, secondary to disease recurrence, or chronic rejection. Indications for TIPS remain same in the transplant patients; however, major difference is altered vascular anatomy, for which adjunct techniques may be required to create TIPS.

Interventional treatment for portal vein complications utilizing a hybrid operating room after liver transplantation

BACKGROUND

Vascular complications after liver transplantation (LT) can be lethal and require immediate treatment to prevent graft failure. Nowadays, with interventional radiology (IR), approaches such as the percutaneous transhepatic (PTH) and transileocolic venous (TIC), have become major treatment options. We reviewed the safety and efficacy of a hybrid operating room (OR) for portal vein complications after LT.

METHODS

Patients who underwent IR for post-LT vascular complications in the hybrid OR from May 2014 to May 2022 were enrolled. Patients who underwent post-LT IR in conventional angiography rooms were excluded.

RESULTS

Nine patients developed portal vein complications; eight after living donor LT and one after deceased donor LT. Six patients had portal vein stenosis, two had portal vein thrombosis, and one had both. In the hybrid OR, PTH and TIC were used in five and three cases, respectively. The Rendezvous technique was used in one case. Angioplasty was performed in all patients. A stent was placed in four patients. The portal venous pressure gradient across the stenotic site significantly decreased after IR (P &= 0.031). The IR success rate in the hybrid OR was 100%.

CONCLUSION

The hybrid OR enables us to accomplish IR for post-LT vascular complications safely and effectively.

Role of interventional radiology in management of post-liver transplant anastomotic complications

Background

Liver transplantation is considered to be the treatment of choice in cases of end-stage liver disease; however, as a major procedure, the operation is fraught with complications. The etiology, symptoms, and diagnostic methods for arterial, portal, and biliary issues are thoroughly discussed. Interventional procedures such as balloon angioplasty and stent placement in the arterial and portal systems, as well as biliary interventional procedures, are described.

Results

In our study, we reviewed 25 cases of post-living donor transplanted liver, with anastomotic complications including biliary stenosis 40%, hepatic vein stenosis 20%, portal vein stenosis 16%, biliary leakage 16%, and hepatic artery stenosis or pseudo-aneurysm 16%. We had 10 cases of biliary stenosis, 7 of which were successfully treated with the insertion of an internal/external drain, and one case failed. Two patients died. We had four cases of hepatic venous obstruction with successfully implanted stents and a perfect outcome, efficacy, and patency rate of 100%. We also had two cases of hepatic artery stenosis that were perfectly managed by stent placement, with a patency rate of 100%. We came across two cases of hepatic artery pseudo-aneurysm. One case failed due to large sac size, while the other was successful. Finally, in our study, we had a 100% success rate in 5 cases of portal vein stenosis in the early postoperative period.

Conclusions

Percutaneous IR was effective treatment for hepatic vein occlusion, portal vein stenosis, hepatic artery stenosis, and anastomotic biliary stricture after living donor liver transplantation. The interventional radiology team is now an integral part of the multi-disciplinary care of transplant patients. As new interventional instruments are developed and experience is gained, the outcomes of interventional treatments will continue to improve.