Estimating the effect of increasing utilization of living donor liver transplantation using observational data.

There has been a recent increase in enthusiasm for expansion of living donor liver transplantation (LDLT) programmes. Using all adults initially placed on the waiting list in the United States, we estimated the risk of overall mortality under national strategies which differed in their utilization of LDLT. We used a generalization of inverse probability weighting which can estimate the effect of interventions in the setting of finite resources. From 2005 to 2015, 93 812 eligible individuals were added to the waitlist: 51 322 received deceased donor grafts while 1970 underwent LDLT. Individuals who underwent LDLT had more favourable prognostic factors, including lower mean MELD score at transplant (14.6 vs. 20.5). The 1-year, 5-year and 10-year cumulative incidence of death under the current level of LDLT utilization were 18.0% (95% CI: 17.8, 18.3%), 41.2% (95% CI: 40.8, 41.5%) and 57.4% (95% CI: 56.9, 57.9%) compared to 17.9% (95% CI: 17.7, 18.2%), 40.6% (95% CI: 40.2, 40.9%) and 56.4% (95% CI: 55.8, 56.9%) under a strategy which doubles LDLT utilization. Expansion of LDLT utilization would have a measurable, modest effect on the risk of mortality for the entire cohort of individuals who begin on the transplant waiting list.

The meaning of confounding adjustment in the presence of multiple versions of treatment: an application to organ transplantation.

Causal inference for treatments with many versions requires a careful specification of the versions of treatment. Specifically, the existence of multiple relevant versions of treatment has implications for the selection of confounders. To illustrate this, we estimate the effect of organ transplantation using grafts from donors who died due to anoxic drug overdose, on recipient graft survival in the US. We describe how explicitly outlining the target trial (i.e. the hypothetical randomized trial which would answer the causal question of interest) to be emulated by an observational study analysis helps conceptualize treatment versions, guides selection of appropriate adjustment variables, and helps clarify the settings in which causal effects of compound treatments will be of value to decision-makers.

The influence of functional warm ischemia time on DCD liver transplant recipients' outcomes.

BACKGROUND: Duration of functional warm ischemia (f-WIT) is thought to have a causal effect on outcomes in controlled donation after circulatory death (DCD) liver transplantation (LT). METHODS: A retrospective cohort study was conducted at five centers. Data were extracted on donor and recipient characteristics, with attention to parameters recorded during withdrawal of life support to in situ cold perfusion. F-WIT was the time elapsed from any of the hemodynamic and oxygenation parameters to the start of in situ cold perfusion. Parameters were as follows: MAP ≤ 50 mm Hg; SBP ≤ 50 mm Hg; and SPO2 ≤ 60%. The primary endpoint was a composite of disseminated ischemic cholangiopathy (IC), primary non-function (PNF), and early graft failure. RESULTS: 35 patients (14%) developed one or more of the primary outcomes. On univariate analysis, older donors and longer WITs were associated with greater likelihood of complications. Of the f-WIT variations analyzed, only f-WIT with SpO2 ≤ 60% was longer among patients with complications. On multivariate analysis, only donor age was a significant predictor of complications. CONCLUSION: This study demonstrates that, of the f-WITs, f-WIT with SpO2 ≤ 60% is most predictive of post-DCD complications. However, results suggest that there may be an alternate etiology for poor outcomes, and that donor age plays a key role.

Optimizing associated liver partition and portal vein ligation for staged hepatectomy outcomes: Surgical experience or appropriate patient selection?

BACKGROUND: Early reports of associated liver partition and portal vein ligation for staged hepatectomy (ALPPS) outcomes have been suboptimal. The literature has confirmed that learning curves influence surgical outcomes. We have 54 months of continuous experience performing ALPPS with strict selection criteria. This study aimed to evaluate the impact of the learning curve on ALPPS outcomes. METHODS: We retrospectively compared patients who underwent ALPPS between April 2012 and March 2016. Patients were grouped into 2 24-month (early and late) periods. All candidates had a high tumour load requiring staged hepatectomy after chemotherapy response, a predicted future liver remnant (FLR) less than 30% and good performance status. RESULTS: Thirty-three patients underwent ALPPS during the study period: 16 in the early group (median age 65 yr, mean body mass index [BMI] 27) and 17 in the late group (median age 60 yr, mean BMI 25). Bilobar disease was comparable in both groups (94% v. 88%, p > 0.99). Duration of surgery was not statistically different. Intraoperative blood loss and need for transfusion were significantly lower in the late group (200 ± 109 mL v. 100 ± 43 mL, p < 0.05). The late group had a higher proportion of monosegment ALPPS (4:1). There were no deaths within 90 days in either cohort. Rates of postoperative complications were not statistically significant between groups. The R0 resection rate was similar. The entire 1-year disease-free and overall survival were 52% and 84%, respectively. CONCLUSION: Excellent results can be obtained in innovative complex surgery with careful patient selection and good technical skills. Additionally, the learning curve brought confidence to perform more complex procedures while maintaining good outcomes.

CONTEXTE: Les premiers résultats sur l'association de la partition hépatique et de la ligature portale pour l'hépatectomie en 2 temps (ALPPS) sont sous-optimaux. La littérature a confirmé que les courbes d'apprentissage influencent les résultats des interventions chirurgicales. Notre étude reposait sur 54 mois consécutifs d'utilisation de la technique ALPPS selon des critères de sélection rigoureux. Elle visait à évaluer l'effet de la courbe d'apprentissage sur les résultats liés à l'ALPPS. MÉTHODES: Nous avons procédé à une comparaison rétrospective des patients traités par l'ALPPS entre avril 2012 et mars 2016. Nous avons divisé les patients en 2 groupes de 24 mois (précoce et tardif). Tous les candidats avaient une charge tumorale élevée nécessitant une hépatectomie en 2 temps après une réponse à la chimiothérapie, un volume estimé de futur foie résiduel (FFR) inférieur à 30 % et un indice fonctionnel favorable. RÉSULTATS: Trente-trois patients ont été traités par l'ALPPS pendant la période de l'étude : 16 dans le groupe précoce (âge médian 65 ans, indice de masse corporelle [IMC] moyen 27) et 17 dans le groupe tardif (âge médian 60 ans, IMC moyen 25). Le taux de maladie bilobaire était comparable entre les 2 groupes (94 % c. 88 %, p > 0,99). La durée de la chirurgie n'était pas statistiquement différente. Les pertes de sang peropératoires et le besoin de transfusion étaient significativement inférieurs dans le groupe tardif (200 ± 109 mL c. 100 ± 43 mL, p < 0,05). Le groupe tardif avait une proportion plus élevée d'ALPPS mono-segmentaires (4:1). Il n'y a eu aucun décès dans les 90 jours parmi les 2 cohortes. Les taux de complications postopératoires n'étaient pas statistiquement significatifs entre les groupes. Le taux de résection R0 était similaire. Les taux de survie sans récidive après une année complète et de survie globale étaient de 52 % et de 84 %, respectivement. CONCLUSION: L'innovation dans le domaine des chirurgies complexes peut donner d'excellents résultats lorsqu'on sélectionne attentivement les patients et que l'on possède de bonnes habiletés techniques. De plus, la courbe d'apprentissage a eu pour effet d'accroître la confiance dans la capacité de réaliser des interventions complexes tout en produisant de bons résultats.

Kidney and liver transplants from donors after cardiac death: initial experience at the London Health Sciences Centre.

BACKGROUND: The disparity between the number of patients waiting for an organ transplant and availability of donor organs increases each year in Canada. Donation after cardiac death (DCD), following withdrawal of life support in patients with hopeless prognoses, is a means of addressing the shortage with the potential to increase the number of transplantable organs. METHODS: We conducted a retrospective, single-centre chart review of organs donated after cardiac death to the Multi-Organ Transplant Program at the London Health Sciences Centre between July 2006 and December 2007. In total, 34 solid organs (24 kidneys and 10 livers) were procured from 12 DCD donors. RESULTS: The mean age of the donors was 38 (range 18-59) years. The causes of death were craniocerebral trauma (n = 7), cerebrovascular accident (n = 4) and cerebral hypoxia (n = 1). All 10 livers were transplanted at our centre, as were 14 of the 24 kidneys; 10 kidneys were transplanted at other centres. The mean renal cold ischemia time was 6 (range 3-9.5) hours. Twelve of the 14 kidney recipients (86%) experienced delayed graft function, but all kidneys regained function. After 1-year follow-up, kidney function was good, with a mean serum creatinine level of 145 (range 107-220) micromol/L and a mean estimated creatinine clearance of 64 (range 41-96) mL/min. The mean liver cold ischemia time was 5.8 (range 5.5-8) hours. There was 1 case of primary nonfunction requiring retransplantation. The remaining 9 livers functioned well. One patient developed a biliary anastomotic stricture that resolved after endoscopic stenting. All liver recipients were alive after a mean follow-up of 11 (range 3-20) months. Since the inception of this DCD program, the number of donors referred to our centre has increased by 14%. CONCLUSION: Our initial results compare favourably with those from the transplantation of organs procured from donors after brain death. Donation after cardiac death can be an important means of increasing the number of organs available for transplant, and its widespread implementation in Canada should be encouraged.

Interpreting Outcomes in DCDD Liver Transplantation: First Report of the Multicenter IDOL Consortium.

BACKGROUND: In the United States, 5% of adult liver transplant recipients receive a graft donation after circulatory determination of death (DCDD). Concerns for ischemic cholangiopathy (IC), a disease of diffuse intrahepatic stricturing limits broader DCDD use. Single-center reports demonstrate large variation in outcomes. METHODS: Retrospective deidentified data collected between 2005 and 2013 were entered electronically by 10 centers via a Research Electronic Data Capture database. Our primary outcome was development of intrahepatic biliary strictures consistent with IC. RESULTS: Within 6 months post-DCDD transplant, 162 (21.8%) patients developed a biliary stricture, of which 88 (11.8%) exhibited intrahepatic structuring consistent with IC. Unadjusted 6-month IC rate among the 10 centers varied significantly (P = 0.006) from 6.3% to 25.9%. The only factor associated with increased risk of IC within 6 months was Roux-en-Y hepaticojejunostomy (vs duct-to-duct) (odds ratio, 3.06; 95% confidence interval, 1.52-6.16; P = 0.002). Graft failure by 6 months was more than 3 times higher for DCDD recipients with IC (odds ratio for IC, 3.36; 95% confidence interval, 1.95-5.79). CONCLUSIONS: This first report of the large combined experience with DCDD from the Improving DCDD Outcomes in Liver Transplant consortium demonstrates significant differences in IC among centers, the importance of biliary strictures as a risk factor for graft failure, and does not validate other risk factors for IC found in smaller studies.

Reuse of liver grafts following the brain death of the initial recipient.

AIM: To determine if there is a reasonable prospect of success of a re-use liver transplantation. METHODS: We systematically searched for reports of liver graft re-use using electronic searches of PubMed and Web of Knowledge. We performed hand searches of references lists of articles reporting re-use of grafts. RESULTS: A systematic review of the literature reveals 28 liver transplantations using previously transplanted grafts. First and second recipients ranged in age from 4 to 72 years and 29 to 62 years respectively. Liver disease in the first recipient was varied including 5 (18%) patients with fulminant liver failure who died subsequently of cerebral edema. The second transplantation was performed after a median interval of 5 d (one day-13 years). Viral hepatitis was present in 3 (11%) of the initial recipients and in 8 (29%) of final recipients. Hepatocellular carcinoma was present in 6 (21%) of the final recipients. Early survival after the final transplantation was 93%, whereas long-term survival was 78% with a mean follow-up of 23.3 (3-120) mo. CONCLUSION: Outcomes of transplantation using previously transplanted grafts in this select population are similar to those seen with conventional grafts.

Increased risk of severe recurrence of hepatitis C virus in liver transplant recipients of donation after cardiac death allografts.

BACKGROUND: In hepatitis C virus (HCV) recipients of donation after cardiac death (DCD) grafts, there is suggestion of lower rates of graft survival, indicating that DCD grafts themselves may represent a significant risk factor for severe recurrence of HCV. METHODS: We evaluated all DCD liver transplant recipients from August 2006 to February 2011 at our center. Recipients with HCV who received a DCD graft (group 1, HCV+ DCD, n=17) were compared with non-HCV recipients transplanted with a DCD graft (group 2, HCV- DCD, n=15), and with a matched group of HCV recipients transplanted with a donation after brain death (DBD) graft (group 3, HCV+ DBD, n=42). RESULTS: A trend of poorer graft survival was seen in HCV+ patients who underwent a DCD transplant (group 1) compared with HCV- patients who underwent a DCD transplant (group 2) (P=0.14). Importantly, a statistically significant difference in graft survival was seen in HCV+ patients undergoing DCD transplant (group 1) (73%) as compared with DBD transplant (group 3) (93%)(P=0.01). There was a statistically significant increase in HCV recurrence at 3 months (76% vs. 16%) (P=0.005) and severe HCV recurrence within the first year (47% vs. 10%) in the DCD group (P=0.004). CONCLUSIONS: HCV recurrence is more severe and progresses more rapidly in HCV+ recipients who receive grafts from DCD compared with those who receive grafts from DBD. DCD liver transplantation in HCV+ recipients is associated with a higher rate of graft failure compared with those who receive grafts from DBD. Caution must be taken when using DCD grafts in HCV+ recipients.