A multicentre outcome analysis to define global benchmarks for donation after circulatory death liver transplantation

BACKGROUND & AIMS

The concept of benchmarking is established in the field of transplant surgery; however, benchmark values for donation after circulatory death (DCD) liver transplantation are not available. Thus, we aimed to identify the best possible outcomes in DCD liver transplantation and to propose outcome reference values.

METHODS

Based on 2,219 controlled DCD liver transplantations, collected from 17 centres in North America and Europe, we identified 1,012 low-risk, primary, adult liver transplantations with a laboratory MELD score of ≤20 points, receiving a DCD liver with a total donor warm ischemia time of ≤30 minutes and asystolic donor warm ischemia time of ≤15 minutes. Clinically relevant outcomes were selected and complications were reported according to the Clavien-Dindo-Grading and the comprehensive complication index (CCI). Corresponding benchmark cut-offs were based on median values of each centre, where the 75^th-percentile was considered.

RESULTS

Benchmark cases represented between 19.7% and 75% of DCD transplantations in participating centres. The 1-year retransplant and mortality rates were 4.5% and 8.4% in the benchmark group, respectively. Within the first year of follow-up, 51.1% of recipients developed at least 1 major complication (≥Clavien-Dindo-Grade III). Benchmark cut-offs were ≤3 days and ≤16 days for ICU and hospital stay, ≤66% for severe recipient complications (≥Grade III), ≤16.8% for ischemic cholangiopathy, and ≤38.9 CCI points 1 year after transplant. Comparisons with higher risk groups showed more complications and impaired graft survival outside the benchmark cut-offs. Organ perfusion techniques reduced the complications to values below benchmark cut-offs, despite higher graft risk.

CONCLUSIONS

Despite excellent 1-year survival, morbidity in benchmark cases remains high. Benchmark cut-offs targeting morbidity parameters offer a valid tool to assess the protective value of new preservation technologies in higher risk groups and to provide a valid comparator cohort for future clinical trials.

LAY SUMMARY

The best possible outcomes after liver transplantation of grafts donated after circulatory death (DCD) were defined using the concept of benchmarking. These were based on 2,219 liver transplantations following controlled DCD donation in 17 centres worldwide. Donor and recipient combinations with higher risk had significantly worse outcomes. However, the use of novel organ perfusion technology helped high-risk patients achieve similar outcomes as the benchmark cohort.

Sequential Protocol Biopsies Post-Liver Transplant From Donors With Moderate Macrosteatosis: What Happens to the Fat?

The number of steatotic deceased donor livers encountered has continued to rise as a result of the obesity epidemic. Little is known about the histological characteristics of moderately macrosteatotic livers over time in the recipient following liver transplantation (LT). All recipients undergoing LT at Mayo Clinic Florida with donor livers with moderate macrosteatosis (30%-60%) from 2000-2017 were identified (n = 96). Routine protocol liver biopsies were performed 1-week and 6-months following LT. All liver donor and protocol biopsies were read by an experienced liver pathologist. Of the 96 moderate macrosteatosis LTs, 70 recipients had post-LT protocol liver biopsies available and comprised the study cohort. Median donor allograft macrosteatosis at the time of transplant was 33% (IQR, 30%-40%) compared with 0% (IQR, 0%-2%) at 1-week (P < 0.001) and 0% (IQR, 0%-0%) at 6-months (P < 0.001) following LT. Biopsies at 1-week post-LT displayed pericentral necrosis in 57.1% of recipients and lipopeliosis in 34.3% of recipients. In the 6-month post-LT biopsies, cholestasis was seen in 3 (4.3%) of the recipients, whereas grade 2 fibrosis was seen in 6 recipients (8.6%). Graft survival at 5 years in the present cohort was 74.0%. Moderate macrosteatosis (30%-60%) in the donor allograft demonstrates complete reversal on liver biopsies performed as early as 7 days following LT and remains absent at 6-months following LT. Both pericentral necrosis and lipopeliosis are common features on day 7 biopsies. Despite these encouraging findings, the perioperative risks of using these livers (postreperfusion cardiac arrest and primary nonfunction) should not be understated. Long-term graft survival is acceptable in patients who are able to overcome the immediate perioperative risk of using moderately steatotic donor livers.

Does Donor Allograft Microsteatosis Matter? Comparison of Outcomes in Liver Transplantation With a Propensity-Matched Cohort

It has been suggested that microsteatosis does not negatively impact graft survival following liver transplantation (LT). The present study represents the largest series on donor livers with significant microsteatosis and investigates the impact of microsteatosis on perioperative factors such as postreperfusion syndrome (PRS), early allograft dysfunction (EAD), and postoperative renal dysfunction. Clinical outcomes of all patients undergoing LT with donor livers with isolated microsteatosis (≥30%; n = 239) between 2000 and 2017 were compared with a propensity score-matched cohort of patients undergoing LT with donor livers with no steatosis (n = 239). Patients in the microsteatosis group had a higher rate of PRS (33.1% versus 24.2%; P = 0.03), EAD (38.2% versus 23.0%; P < 0.001), and continuous renal replacement therapy (CRRT) requirement following LT (10.9% versus 3.6%; P = 0.002) than the no steatosis group. No difference in patient (P = 0.33) or graft survival (P = 0.18) was observed between the 2 groups. On multivariate regression, livers with microsteatosis had an increased risk of graft loss with retransplant recipients (hazard ratio [HR], 1.59; P < 0.001), increasing Model for End-Stage Liver Disease (MELD) score (HR, 1.13; P = 0.01), and organs from donation after circulatory death donors (HR, 1.46; P = 0.003). In conclusion, recipients of donor livers with significant microsteatosis are at an increased risk of PRS, EAD, and postoperative renal dysfunction requiring CRRT. Livers with significant microsteatosis should be avoided in retransplant recipients and in recipients with high biological MELD scores. Once appropriately selected recipients of these livers are able to overcome the initial perioperative implications of using these donor livers, longterm patient and graft survival is similar to recipients receiving grafts with no steatosis.

The impact of postreperfusion syndrome during liver transplantation using livers with significant macrosteatosis

The impact of postreperfusion syndrome (PRS) during liver transplantation (LT) using donor livers with significant macrosteatosis is largely unknown. Clinical outcomes of all patients undergoing LT with donor livers with moderate macrosteatosis (30%-60%) (N = 96) between 2000 and 2017 were compared to propensity score matched cohorts of patients undergoing LT with donor livers with mild macrosteatosis (10%-29%) (N = 96) and no steatosis (N = 96). Cardiac arrest at the time of reperfusion was seen in eight (8.3%) of the patients in the moderate macrosteatosis group compared to one (1.0%) of the patients in the mild macrosteatosis group (P = .02) and zero (0%) of the patients in the no steatosis group (P = .004). Patients in the moderate macrosteatosis group had a higher rate of PRS (37.5% vs 18.8%; P = .004), early allograft dysfunction (EAD) (76.4% vs 25.8%; P < .001), renal dysfunction requiring continuous renal replacement therapy following transplant (18.8% vs 8.3%; P = .03) and return to the OR within 30 days (24.0% vs 7.3%; P = .002), than the no steatosis group. Both long-term patient (P = .30 and P = .08) and graft survival (P = .15 and P = .12) were not statistically when comparing the moderate macrosteatosis group to the mild macrosteatosis and no steatosis groups. Recipients of LT using livers with moderate macrosteatosis are at a significant increased risk of PRS. If patients are able to overcome the initial increased perioperative risk of using these donor livers, long-term graft survival does not appear to be different than matched recipients receiving grafts with no steatosis.