Special Issues of DCD
As a measure to increase the donor pool, DCD has been increasingly performed in many countries. During the additional period of WIT without organ preservation stasis and thrombus formation in small vessels is expedited. Since also the peribiliary plexus is involved, the incidence of biliary complications is almost doubled. An 'ischemic cholangiopathy' evolves in >20% of recipients. The clinical picture is similar to NAS of other etiology, but it manifests regularly within 3 months after LT. Its clinical course is often more severe and retransplantation required in a significant percentage. Analysis of the UNOS database of 2351 DCD-LT revealed a significantly decreased patient and graft survival with a 5-year graft survival rate of 56%. In this analysis CIT >8 h, donor age >50 years and donor WIT ≥ 20 min were identified as most relevant graft related factors for graft failure, but biliary complications were not specifically analyzed. However, single center experiences report overall results after DCD-LT, which are not significantly different from LT with donation after brain death. In a specialized experience with careful donor selection the incidence of ischemic cholangiopathy was only 12.6%. However, 70% of the affected patients either died or underwent retransplantation.
The time from asystole to cross-clamp has been identified as major risk factor for the development of ischemic cholangiopathy. Thereby the authors have calculated that each minute of additional WIT increases the odds ratio for the development of ischemic cholangiopathy or hepatic necrosis by 16%. Also other risk factors, known from donation after brain death, have been confirmed in a US cohort of 1567 DCD-LT including donor age, donor weight and CIT. In view of the high biliary complication risk routine surveillance might be important in the early period after LT. This is relieved by insertion of a biliary drainage either via the transcystic route or as T-tube to facilitate early therapeutic intervention. Other, potentially preventive strategies recommended by the ASTS include limitation of the total WIT to less than 30–45 min, limitation of the cold ischmia time to less than 8–10 h and especially staying at the lower limit of both in older donors and fatty livers. Moreover simultaneous arterial and portal revascularization should be considered.
Innovative approaches for lowering the biliary mobidity of DCD-LT include thrombolytic agents or machine perfusion. First clinical results using backtable injection of tissue plasminogen activator (TPA) into the donor hepatic artery before DCD-LT revealed a low incidence of ischemic cholangiopathy of 9% and an overall biliary complication rate of 27%. However, excessive bleeding evolved in two-third of the recipients, mainly if other risk factors like poor graft quality or severe adhesions were present In conclusion, DCD-LT is a suitable method to expand the donor pool, a careful donor selection (avoid accumulation of risk factors) and an optimum management of organ procurement (CIT, WIT, consider TPA) and transplantation (simultaneous revascularization, early surveillance for biliary complications) provided.