Combining Oxygenated Cold Perfusion With Normothermic Ex Vivo Perfusion Improves the Outcome of Donation After Circulatory Death Porcine Kidney Transplantation.

BACKGROUND: Ex vivo machine perfusion is a novel preservation technique for storing and assessing marginal kidney grafts. All ex vivo perfusion techniques have advantages and shortcomings. The current study analyzed whether a combination of oxygenated hypothermic machine perfusion (oxHMP) followed by a short period of normothermic ex vivo kidney perfusion (NEVKP) could combine the advantages of both techniques. METHODS: Porcine kidneys were exposed to 30 min of warm ischemia followed by perfusion. Kidneys underwent either 16-h NEVKP or 16-h oxHMP. The third group was exposed to 16-h oxHMP followed by 3-h NEVKP (oxHMP + NEVKP group). After contralateral nephrectomy, grafts were autotransplanted and animals were followed up for 8 d. RESULTS: All animals survived the follow-up period. Grafts preserved by continuous NEVKP showed improved function with lower peak serum creatinine and more rapid recovery compared with the other 2 groups. Urine neutrophil gelatinase-associated lipocalin, a marker of kidney injury, was found to be significantly lowered on postoperative day 3 in the oxHMP + NEVKP group compared with the other 2 groups. CONCLUSIONS: A short period of NEVKP after oxHMP provides comparable short-term outcomes to prolonged NEVKP and is superior to oxHMP alone. A combination of oxHMP with end-ischemic NEVKP could be an attractive, practical strategy to combine the advantages of both preservation techniques.

Dynamic Metabolic Changes During Prolonged Ex Situ Heart Perfusion Are Associated With Myocardial Functional Decline.

Ex situ heart perfusion (ESHP) was developed to preserve and evaluate donated hearts in a perfused beating state. However, myocardial function declines during ESHP, which limits the duration of perfusion and the potential to expand the donor pool. In this research, we combine a novel, minimally-invasive sampling approach with comparative global metabolite profiling to evaluate changes in the metabolomic patterns associated with declines in myocardial function during ESHP. Biocompatible solid-phase microextraction (SPME) microprobes serving as chemical biopsy were used to sample heart tissue and perfusate in a translational porcine ESHP model and a small cohort of clinical cases. In addition, six core-needle biopsies of the left ventricular wall were collected to compare the performance of our SPME sampling method against that of traditional tissue-collection. Our state-of-the-art metabolomics platform allowed us to identify a large number of significantly altered metabolites and lipid species that presented comparable profile of alterations to conventional biopsies. However, significant discrepancies in the pool of identified analytes using two sampling methods (SPME vs. biopsy) were also identified concerning mainly compounds susceptible to dynamic biotransformation and most likely being a result of low-invasive nature of SPME. Overall, our results revealed striking metabolic alterations during prolonged 8h-ESHP associated with uncontrolled inflammation not counterbalanced by resolution, endothelial injury, accelerated mitochondrial oxidative stress, the disruption of mitochondrial bioenergetics, and the accumulation of harmful lipid species. In conclusion, the combination of perfusion parameters and metabolomics can uncover various mechanisms of organ injury and recovery, which can help differentiate between donor hearts that are transplantable from those that should be discarded.

Renal Dysfunction After Liver Transplantation: Effect of Donor Type.

Recipients of donation after circulatory death (DCD) grafts are reportedly at higher risk of developing renal dysfunction after liver transplantation (LT). We compared the development of acute kidney injury (AKI) and chronic kidney disease (CKD) after LT in recipients of DCD versus donation after brain death (DBD) or living donor liver transplantation (LDLT) livers. Adult recipients of DBD, LDLT, and DCD between 2012 and 2016 at Toronto General Hospital were included. AKI was defined as a post-LT increase of serum creatinine (sCr) ≥26.5 µmol/L within 48 hours or a ≥50% increase from baseline, and CKD was defined as an estimated glomerular filtration rate <60 mL/minute for >3 months. A total of 681 patients (DCD, n = 57; DBD, n = 446; and LDLT, n = 178) with similar baseline comorbidities were included. Perioperative AKI (within the first 7 postoperative days) was observed more frequently in the DCD group (61%; DBD, 40%; and LDLT, 44%; P = 0.01) and was associated with significantly higher peak AST levels (P < 0.001). Additionally, patients in the DCD group had a significantly higher peak sCr (P < 0.001) and a trend toward higher rates of AKI stage 3 (DCD, 33%; DBD, 21%; LDLT, 21%; P = 0.11). The proportions of recovery from AKI (DCD, 77%; DBD, 72%; LDLT, 78%; P = 0.45) and patients developing CKD (DCD, 33%; DBD, 32%; LDLT, 32%; P = 0.99) were similar. Nevertheless, patients who received DCD or DBD LT and required perioperative renal replacement therapy showed significantly lower patient survival in multivariate analysis (hazard ratio, 7.90; 95% confidence interval, 4.51-13.83; P < 0.001). In conclusion, recipients of DCD liver grafts experience higher rates of short-term post-LT renal dysfunction compared with DBD or LDLT. Additional risk factors for the development of severe kidney injury, such as high Model for End-Stage Liver Disease score, massive transfusions, or donor age ≥60 years should be avoided.

Normothermic Ex Vivo Liver Perfusion Prevents Intrahepatic Platelet Sequestration After Liver Transplantation.

BACKGROUND: The detrimental role of platelets in sinusoidal endothelial cell (SEC) injury during liver transplantation (LT) has been previously addressed after static cold storage (SCS), however, it is currently unknown after normothermic ex vivo liver perfusion (NEVLP). METHODS: Pig LT was performed with livers from heart-beating donors or donation after circulatory death (DCD) donors subjected to SCS or NEVLP (n = 5/group). RESULTS: All pigs except for 1 (DCD-SCS-group) survived 4 days. The heart-beating donor- and DCD-NEVLP-groups showed significantly lower aspartate transaminase-levels compared with the SCS-groups 3 hours post-LT (P = 0.006), on postoperative day (POD) 2 (P = 0.005), POD3 (P = 0.007), and on POD4 (P = 0.012). Post-LT total platelet count recovered faster in the NEVLP than in the SCS-groups at 12 hours (P = 0.023) and 24 hours (P = 0.0038). Intrahepatic sequestration of platelets was significantly higher in the SCS-groups 3 hours postreperfusion and correlated with severity of SEC injury. In both SCS-groups, levels of tumor growth factor-ß were higher 3 hours post-LT, on POD1 and on POD3. Moreover, platelet factor 4 levels and platelet-derived extracellular vesicles were increased in the SCS-groups. Hyaluronic acid levels were significantly higher in the SCS-groups, indicating a higher grade of endothelial cell dysfunction. Platelet inhibition achieved by pretreatment with clopidogrel (n = 3) partly reversed the detrimental effects on SEC injury and therefore provided further evidence of the important role of platelets in ischemia/reperfusion injury and SEC injury. CONCLUSIONS: Normothermic perfusion of liver grafts before transplantation effectively reduced platelet aggregation and SEC injury, which translated into an improved posttransplant organ function.

Impact of Different Clinical Perfusates During Normothermic Ex Situ Liver Perfusion on Pig Liver Transplant Outcomes in a DCD Model.

BACKGROUND: Human albumin/dextran (HA-D), bovine-gelatin (BG), and packed red blood cells plus plasma have been used in European and North-American clinical trials of normothermic ex situ liver perfusion (NEsLP). We compared the effects of these perfusates in a porcine model during NEsLP and after transplantation. METHODS: Porcine livers were retrieved 30 minutes after circulatory death. After 5 hours of NEsLP, grafts were transplanted. Three groups (n = 6) were assessed (HA-D vs BG vs whole blood [WB]). One group of static cold storage (SCS) was evaluated for comparison with the perfusion groups. Hemodynamic variables, liver and endothelial injury, and function were assessed during NEsLP and posttransplantation. RESULTS: Hepatic artery flow was higher since the beginning of NEsLP in the HA-D group (HA-D, 238 ± 90 mL/min vs BG, 97 ± 33 mL/min vs WB, 148 ± 49 mL/min; P = 0.01). Hyaluronic acid was lower in the HA-D at the end of perfusion (HA-D, 16.28 ± 7.59 ng/µL vs BG, 76.05 ± 15.30 ng/µL vs WB, 114 ± 46 ng/µL; P < 0.001). After transplant, aspartate aminotransferase was decreased in the HA-D group when compared with the rest of the groups (HA-D, 444 ± 226 IU/L vs BG, 1033 ± 694 IU/L vs WB, 616 ± 444 IU/L vs SCS, 2235 ± 1878 IU/L). At 5 hours after transplant, lactate was lower in the HA-D group (HA-D, 3.88 ± 1.49 mmol/L vs BG, 7.79 ± 2.68 mmol/L vs WB, 8.16 ± 3.86 mmol/L vs SCS, 9.06 ± 3.54 mmol/L; P = 0.04). International Normalized Ratio was improved in HA-D group compared to the rest of the groups (HA-D, 1.23 ± 0.30 vs BG, 1.63 ± 0.20 vs WB, 1.50 ± 0.31 vs SCS, 1.97 ± 1.55; P = 0.03) after transplantation. In contrast, BG displayed lower aspartate aminotransferase levels during NEsLP (HA-D, 183 ± 53 IU/L vs BG, 142 ± 52 IU/L vs WB, 285 ± 74 IU/L; P = 0.01) and less cleaved-caspase-3 staining (HA-D, 2.05 ± 0.73% vs BG, 0.95 ± 1.14% vs WB, 1.74 ± 0.54% vs SCS, 7.95 ± 2.38%) compared with the other groups. On the other hand, the bile from the WB showed higher pH (HA-D, 7.54 ± 0.11 vs BG, 7.34 ± 0.37 vs WB, 7.59 ± 0.18) and lower glucose levels (HA-D, 0.38 ± 0.75 mmol/L vs BG, 1.42 ± 1.75 mmol/L vs WB, 0 ± 0 mmol/L) by the end of perfusion. CONCLUSIONS: Overall HA-D displayed more physiologic conditions during NEsLP that were reflected in less graft injury and improved liver function and survival after transplantation. Optimization of the perfusates based on the beneficial effects found with these different solutions would potentially improve further the outcomes through the use of NEsLP in marginal grafts.

Predictor parameters of liver viability during porcine normothermic ex situ liver perfusion in a model of liver transplantation with marginal grafts.

Normothermic ex situ liver perfusion (NEsLP) offers the opportunity to assess biomarkers of graft function and injury. We investigated NEsLP parameters (biomarkers and markers) for the assessment of liver viability in a porcine transplantation model. Grafts from heart-beating donors (HBD), and from donors with 30 minutes (donation after cardiac death [DCD]30'), 70 minutes (DCD70'), and 120 minutes (DCD120') of warm ischemia were studied. The HBD, DCD30', and DCD70'-groups had 100% survival. In contrast, 70% developed primary nonfunction (PNF) and died in the DCD120'-group. Hepatocellular function during NEsLP showed low lactate (≤1.1 mmol/L) in all the groups except the DCD120'-group (>2 mmol/L) at 4 hours of perfusion (P = .04). The fold-urea increase was significantly lower in the DCD120'-group (≤0.4) compared to the other groups (≥0.65) (P = .01). As for cholangiocyte function, bile/perfusate glucose ratio was significantly lower (<0.6) in all the groups except the DCD120'-group (≥0.9) after 3 hours of perfusion (<0.01). Bile/perfusate Na+ ratio was significantly higher (≥1.2) after 3 hours of perfusion in all the groups except for the DCD120'-group (≤1) (P < .01). Three hours after transplantation, the DCD120'-group had a significantly higher international normalized ratio (>5) compared to the rest of the groups (≤1.9) (P = .02). Rocuronium levels were higher at all the time-points in the animals that developed PNF during NEsLP and after transplantation. This study demonstrates that biomarkers and markers of hepatocellular and cholangiocyte function during NEsLP correlate with the degree of ischemic injury and posttransplant function.

Patterns and Predictors of Mortality After Waitlist Dropout of Patients With Hepatocellular Carcinoma Awaiting Liver Transplantation.

BACKGROUND: There is a lack of information about survival after dropout from the liver transplant waiting list. Therefore, we aimed to assess the overall survival, and risk factors for death, after waiting list dropout due to hepatocellular carcinoma (HCC) progression. METHODS: We assessed patients who dropped out of the liver transplant waiting list between 2000 and 2016 in a single, large academic North American center. Patients were divided into 3 groups according to the types of HCC progression: locally advanced disease (LAD), extrahepatic disease (EHD), and macrovascular invasion (MVI). The primary outcome was overall survival. Survival was assessed by the Kaplan-Meier method. Predictors of death after dropout were assessed by multivariable Cox regression. RESULTS: During the study period, 172 patients dropped out due to HCC progression. Of those, 37 (21.5%), 74 (43%), and 61 (35.5%) dropped out due to LAD, EHD, and MVI, respectively. Median survival according to cause of dropout (LAD, EHD, or MVI) was 1.0, 4.4, or 3.3 months, respectively (P = 0.01). Model for End-stage Liver Disease (MELD) score (hazard ratio [HR], 1.04; 95% confidence interval [CI], 1.01-1.08), alcoholic liver disease (HR, 1.66; 95% CI, 1.02-2.71), and α-fetoprotein >1000 ng/mL (HR, 1.86; 95% CI, 1.22-2.84) were predictors of mortality after dropout. Dropout due to EHD (HR, 0.61; 95% CI, 0.38-0.98) and undergoing treatment after dropout were protective factors (HR, 0.32; 95% CI, 0.21-0.48) for death. CONCLUSIONS: Patient prognosis after dropout is dismal. However, a subgroup of patients may have longer survival. The present study identifies the patterns of waitlist dropout in patients with HCC and provides evidence for the effectiveness of treatment strategies offered to HCC patients after dropout.

Splenectomy as Flow Modulation Strategy and Risk Factors of De Novo Portal Vein Thrombosis in Adult-to-Adult Living Donor Liver Transplantation.

Portal vein thrombosis (PVT) is a severe complication after liver transplantation that can result in increased morbidity and mortality. Few data are available regarding risk factors, classification, and treatment of PVT after living donor liver transplantation (LDLT). Between January 2004 and November 2014, 421 adult-to-adult LDLTs were performed at our institution, and they were included in the analysis. Perioperative characteristics and outcomes from patients with no-PVT (n = 393) were compared with those with de novo PVT (total portal vein thrombosis [t-PVT]; n = 28). Ten patients had early portal vein thrombosis (e-PVT) occurring within 1 month, and 18 patients had late portal vein thrombosis (l-PVT) appearing later than 1 month after LDLT. Analysis of perioperative variables determined that splenectomy was associated with t-PVT (hazard ratio [HR], 3.55; P = 0.01), e-PVT (HR, 4.96; P = 0.04), and l-PVT (HR, 3.84; P = 0.03). In contrast, donor age was only found as a risk factor for l-PVT (HR, 1.05; P = 0.01). Salvage rate for treatment in e-PVT and l-PVT was 100% and 50%, respectively, without having an early event of rethrombosis. Mortality within 30 days did not show a significant difference between groups (no-PVT, 2% versus e-PVT, 10%; P = 0.15). No significant differences were found regarding 1-year (89% versus 92%), 5-year (79% versus 82%), and 10-year (69% versus 79%) graft survival between the t-PVT and no-PVT groups, respectively (P = 0.24). The 1-year (89% versus 96%), 5-year (82% versus 86%), and 10-year (79% versus 83%) patient survival was similar for the patients in the no-PVT and t-PVT groups, respectively (P = 0.70). No cases of graft loss occurred as a direct consequence of PVT. In conclusion, the early diagnosis and management of PVT after LDLT can lead to acceptable early and longterm results without affecting patient and graft survival.

Surgical Complications after Right Hepatectomy for Live Liver Donation: Largest Single-Center Western World Experience.

The authors assessed the incidence, management, and risk factors for postoperative complications after right lobe (RL) live donor hepatectomy in a high-volume center in North America. All donors undergoing an RL live donor hepatectomy between 2000 and 2017 at our institution were included. The primary outcome was the development of complications (both medical and surgical). Predictors of postoperative complications were determined by logistic regression. A total of 587 patients underwent RL live donor hepatectomy. Among those, 187 postoperative complications were diagnosed in 141 (24%) patients. One patient had >90-day morbidity, and there were no donor deaths. Overall complications were significantly higher in the first era, 2000 to 2008 (81 [57.4%]) versus the second era, 2009 to 2017 (60 [42.6%]) (p = 0.01). On multivariate analysis, the only predictor of postoperative complications was the center volume of RL live donor hepatectomy in the previous 12 months with an odds ratio of 0.97 (95% confidence interval: 0.95-0.99). In conclusion, increasing center volume is associated with lower rates of postoperative complications after RL living liver donation.

Stereotactic body radiotherapy vs. TACE or RFA as a bridge to transplant in patients with hepatocellular carcinoma. An intention-to-treat analysis.

BACKGROUND & AIMS: There is limited information on the use of stereotactic body radiotherapy (SBRT) as a bridge to liver transplantation for hepatocellular carcinoma and no study comparing its efficacy to transarterial chemoembolization (TACE) and radiofrequency ablation (RFA). We aimed to ascertain the safety and efficacy of SBRT on an intention-to-treat basis compared with TACE and RFA as a bridge to liver transplantation in a large cohort of patients with hepatocellular carcinoma. METHODS: Outcomes between groups were compared from the time of listing and from the time of transplant. Between July 2004 and December 2014, 379 patients were treated with either SBRT (n=36, SBRT group), TACE (n=99, TACE group) or RFA (n=244, RFA group). RESULTS: The drop-out rate was similar between groups (16.7% SBRT group vs. 20.2% TACE group and 16.8% RFA group, p=0.7); 30 patients were transplanted in the SBRT group, 79 in the TACE group and 203 in the RFA group. Postoperative complications were similar between groups. Patients in the RFA group had more tumor necrosis in the explant. The 1-, 3- and 5-year actuarial patient survival from the time of listing was 83%, 61% and 61% in the SBRT group vs. 86%, 61% and 56% in the TACE group, and 86%, 72% and 61% in the RFA group, p=0.4. The 1-, 3- and 5-year survival from the time of transplant was 83%, 75% and 75% in the SBRT group vs. 96%, 75% and 69% in the TACE group, and 95%, 81% and 73% in the RFA group, p=0.7. CONCLUSIONS: In conclusion, SBRT can be safely utilized as a bridge to LT in patients with HCC, as an alternative to conventional bridging therapies. LAY SUMMARY: Patients with liver cancer included in the waiting list for liver transplantation are at risk of tumor progression and death. Stereotactic body radiotherapy may be a good alternative to conventional therapies to reduce this risk.