Risk Score Predicting Decline in Renal Function Postliver Transplant: Role in Patient Selection for Combined Liver Kidney Transplantation

Chronic Kidney Disease After Liver Transplantation

Chronic kidney disease among liver transplant recipients is common and associated with an increased mortality risk. Several risk factors and causes for the development of chronic kidney disease have been identified. They can be divided into perioperative factors, such as unresolved acute kidney injury; donor-related factors, such as the use of extended criteria liver allografts; and recipient-related factors, such as the use of calcineurin inhibitors and the presence of metabolic syndrome, diabetes, and obesity. There is a bimodal progression, more prominent during the initial post-transplant months, followed by a gradual but progressive decline over the subsequent years. Management strategies to prevent and treat chronic kidney disease in the general population can be reasonably applied to the liver transplant population and include addressing comorbidities such as hypertension and diabetes. Strategies to minimize or withdraw calcineurin inhibitors from the immunosuppressive regimen can slow progression of kidney dysfunction. Patients with advanced chronic kidney disease should be considered for kidney transplantation due to its survival advantage. Allocation policy in the United States confers safety-net allocation priority for liver transplant recipients who develop advanced chronic kidney disease within the first year of liver transplantation.

Acute kidney injury and chronic kidney disease after liver transplant: A retrospective observational study

BACKGROUND AND RATIONALE

Chronic kidney disease remains an important risk factor for morbidity and mortality among LT recipients, but its exact incidence and risk factors are still unclear.

MATERIAL AND METHODS

We carried out a retrospective cohort study of consecutive adults who underwent liver transplant (January 2009-December 2018) and were followed (at least 6 months) at our institution. CKD was defined following the Kidney Disease: Improving Global Outcomes (KDIGO) 2012 Clinical Practice Guidelines. Long-term kidney function was classified into 4 groups: no CKD (eGFR, ≥60mL/min/1.73m²), mild CKD (eGFR, 30-59mL/min/1.73m²), severe CKD (eGFR, 15-29mL/min/1.73m²), and end-stage renal disease (ESRD).

RESULTS

We enrolled 410 patients followed for 53.2±32.6 months. 39 had CKD at baseline, and 95 developed de novo CKD over the observation period. There were 184 (44.9%) anti-HCV positive, 47 (11.5%) HBsAg positive, and 33 (8.1%) HBV/HDV positive recipients. Recipient risk factors for baseline CKD were advanced age (P=0.044), raised levels of serum uric acid (P<0.0001), and insulin dependent DM (P=0.0034). Early post-transplant AKI was common (n=95); logistic regression analysis found that baseline serum creatinine was an independent predictor of early post-LT AKI (P=0.0154). According to our Cox proportional hazards model, recipient risk factors for de novo CKD included aging (P<0.0001), early post-transplant AKI (P=0.007), and baseline serum creatinine (P=0.0002). At the end of follow-up, there were 116 LT recipients with CKD - 109 (93.9%) and 7 (6.1%) had stage 3 and advanced CKD, respectively. Only two of them are undergoing long-term dialysis.

CONCLUSION

The incidence of CKD was high in our cohort of LT recipients, but only a slight decline in kidney function over time was recorded. Prevention of post-transplant AKI will improve kidney function in the long run. We need more studies to analyze the function of kidneys among LT recipients over extended follow-ups and their impact on mortality.

Acute kidney injury and chronic kidney disease after liver transplant: A retrospective observational study

BACKGROUND AND RATIONALE

Chronic kidney disease remains an important risk factor for morbidity and mortality among LT recipients, but its exact incidence and risk factors are still unclear.

MATERIAL AND METHODS

We carried out a retrospective cohort study of consecutive adults who underwent liver transplant (January 2009-December 2018) and were followed (at least 6 months) at our institution. CKD was defined following the Kidney Disease: Improving Global Outcomes (KDIGO) 2012 Clinical Practice Guidelines. Long-term kidney function was classified into 4 groups: no CKD (eGFR, ≥60mL/min/1.73m2), mild CKD (eGFR, 30-59mL/min/1.73m2), severe CKD (eGFR, 15-29mL/min/1.73m2), and end-stage renal disease (ESRD).

RESULTS

We enrolled 410 patients followed for 53.2±32.6 months. 39 had CKD at baseline, and 95 developed de novo CKD over the observation period. There were 184 (44.9%) anti-HCV positive, 47 (11.5%) HBsAg positive, and 33 (8.1%) HBV/HDV positive recipients. Recipient risk factors for baseline CKD were advanced age (P=0.044), raised levels of serum uric acid (P<0.0001), and insulin dependent DM (P=0.0034). Early post-transplant AKI was common (n=95); logistic regression analysis found that baseline serum creatinine was an independent predictor of early post-LT AKI (P=0.0154). According to our Cox proportional hazards model, recipient risk factors for de novo CKD included aging (P<0.0001), early post-transplant AKI (P=0.007), and baseline serum creatinine (P=0.0002). At the end of follow-up, there were 116 LT recipients with CKD - 109 (93.9%) and 7 (6.1%) had stage 3 and advanced CKD, respectively. Only two of them are undergoing long-term dialysis.

CONCLUSION

The incidence of CKD was high in our cohort of LT recipients, but only a slight decline in kidney function over time was recorded. Prevention of post-transplant AKI will improve kidney function in the long run. We need more studies to analyze the function of kidneys among LT recipients over extended follow-ups and their impact on mortality.

The AKI Prediction Score: a new prediction model for acute kidney injury after liver transplantation

BACKGROUND

Acute kidney injury (AKI) is a frequent complication after liver transplantation. Although numerous risk factors for AKI have been identified, their cumulative impact remains unclear. Our aim was therefore to design a new model to predict post-transplant AKI.

METHODS

Risk analysis was performed in patients undergoing liver transplantation in two centres (n = 1230). A model to predict severe AKI was calculated, based on weight of donor and recipient risk factors in a multivariable regression analysis according to the Framingham risk-scheme.

RESULTS

Overall, 34% developed severe AKI, including 18% requiring postoperative renal replacement therapy (RRT). Five factors were identified as strongest predictors: donor and recipient BMI, DCD grafts, FFP requirements, and recipient warm ischemia time, leading to a range of 0-25 score points with an AUC of 0.70. Three risk classes were identified: low, intermediate and high-risk. Severe AKI was less frequently observed if recipients with an intermediate or high-risk were treated with a renal-sparing immunosuppression regimen (29 vs. 45%; p = 0.007).

CONCLUSION

The AKI Prediction Score is a new instrument to identify recipients at risk for severe post-transplant AKI. This score is readily available at end of the transplant procedure, as a tool to timely decide on the use of kidney-sparing immunosuppression and early RRT.

VI consensus document by the Spanish Liver Transplantation Society

The goal of the Spanish Liver Transplantation Society (La Sociedad Española de Trasplante Hepático) is to promote and create consensus documents about current topics in liver transplantation with a multidisciplinary approach. To this end, on October 20, 2016, the 6th Consensus Document Meeting was held, with the participation of experts from the 24 authorized Spanish liver transplantation programs. This Edition discusses the following subjects, whose summary is offered below: 1) limits of simultaneous liver-kidney transplantation; 2) limits of elective liver re-transplantation; and 3) liver transplantation after resection and hepatocellular carcinoma with factors for a poor prognosis. The consensus conclusions for each of these topics is provided below.

Chronic kidney disease in liver transplantation: Evaluation of kidney function

Chronic kidney disease is one of the main comorbidities affecting liver transplant recipients. Most of those patients have some degree of acute or chronic kidney dysfunction at the time of transplantation, moreover they can also develop de novo chronic kidney disease once transplanted. An important increase in the incidence of chronic kidney disease in the «MELD era» has been observed. This phenomenon has partially been attributed to the weight that kidney function carries for organ allocation. In addition, the generalized use of calcineurin inhibitors has also been a contributing factor. It is of the utmost importance for us to be familiar with the current methods for evaluating kidney function before and after a liver transplantation. The two main biomarkers available today for that purpose are serum creatinine and cystatin C. Several equations have been derived from those biomarkers and have been tested in that context with mixed results, due to their biologic variability and the lack of standardization in their measurement. The gold standard continues to be the direct determination of the glomerular filtration rate through different methods; however, that is only done for research purposes. It is also essential to know the current classification of acute kidney injury and chronic kidney disease in order to make early diagnosis. The present review focuses on the recognition, diagnosis, and classification of chronic kidney disease and acute kidney injury in liver transplantation recipients.

VI consensus document by the Spanish Liver Transplantation Society

The goal of the Spanish Liver Transplantation Society (La Sociedad Española de Trasplante Hepático) is to promote and create consensus documents about current topics in liver transplantation with a multidisciplinary approach. To this end, on October 20, 2016, the 6th Consensus Document Meeting was held, with the participation of experts from the 24 authorized Spanish liver transplantation programs. This Edition discusses the following subjects, whose summary is offered below: 1) limits of simultaneous liver-kidney transplantation; 2) limits of elective liver re-transplantation; and 3) liver transplantation after resection and hepatocellular carcinoma with factors for a poor prognosis. The consensus conclusions for each of these topics is provided below.

Chronic Kidney Disease and Related Long-Term Complications After Liver Transplantation

Liver transplantation is the standard of care for patients with decompensated cirrhosis. Liver transplantation recipients have excellent short-term and long-term outcomes including patient and graft survival. Since the adoption of model for end-stage liver disease (MELD)-based allocation policy, the incidence of post-transplant end stage renal disease has risen significantly. Occurrence of Stage 4 chronic kidney disease and end stage renal disease substantially increases the risk of post-transplant deaths. Because majority of late post-transplant mortality is due to nonhepatic post-transplant comorbidities, personalized care directed toward risk factor modification may further improve post-transplant survival.

Simulation modeling of the impact of proposed new simultaneous liver and kidney transplantation policies

BACKGROUND

Increasing use of kidney grafts for simultaneous liver and kidney (SLK) transplants is causing concern about the most effective utilization of scarce kidney graft resources. This study evaluated the impact of implementing the proposed United Network for Organ Sharing SLK transplant policy on outcomes for end-stage liver disease (ESLD) and end-stage renal disease (ESRD) patients awaiting transplant.

METHODS

A Markov model was constructed to simulate a hypothetical cohort of ESLD patients over a 30-year time horizon starting from age 50. The model applies the different criteria being considered in the United Network for Organ Sharing policy and tallies outcomes, including numbers of procedures and life years after liver transplant alone (LTA) or SLK transplant.

RESULTS

When 1-week pretransplant dialysis duration is required, the numbers of SLK transplants and LTAs would be 648 and 9,065, respectively. If the pretransplant dialysis duration is extended to 12 weeks, there would be 240 SLK transplants and 9,426 LTAs. This change results in a decrease of 6,483 life years among SLK transplant recipients and an increase of 4,971 life years among LTA recipients. However, by increasing the dialysis duration to 12 weeks from 1 week, 408 kidney grafts would be released to the kidney waitlist because of the decline in SLK transplants; this yields 796 additional life years gained among ESRD patients.

CONCLUSION

Implementation of the proposed SLK transplant policy could restore access to kidney transplants for patients with ESRD albeit at the detriment of patients with ESLD and renal impairment.

Renal dysfunction and the liver transplant recipient; novel strategies for determination of reversibility and renal protective therapies pretransplant and posttransplant

PURPOSE OF REVIEW

Renal dysfunction is one of the most common and important complications in liver transplant candidates and recipients. Recent publications have highlighted important developments in this field.

RECENT FINDINGS

Inclusion of the serum creatinine in the Model for Endstage Liver Disease (MELD) score has led to an increased number of liver transplant candidates and recipients with renal dysfunction. The development of posttransplant renal dysfunction negatively impacts patient survival. Therefore, the careful identification of appropriate candidates for simultaneous liver-kidney (SLK) transplant is critical. Recent publications have helped in the appropriate selection of SLK recipients. One of the most important strategies to help mitigate renal dysfunction in liver transplant recipients is the careful management of immunosuppression.

SUMMARY

Important contributing factors to posttransplant renal dysfunction include pretransplant renal disease and immunosuppression, namely calcineurin inhibitors (CNIs). One of the most effective means of preventing posttransplant renal failure is observation of the defined criteria for selecting patients for SLK. In addition, avoidance and minimization of CNIs may help to mitigate posttransplant renal disease.

Predisposing factors of diminished survival in simultaneous liver/kidney transplantation

Since the adoption of the Model for End-Stage Liver Disease, simultaneous liver/kidney transplants (SLKT) have substantially increased. Recently, unfavorable outcomes have been reported yet contributing factors remain unclear. We retrospectively reviewed 74 consecutive adult SLKT performed at our center from 2000 to 2010 and compared with kidney transplant alone (KTA, N = 544). In SLKT, patient and death-censored kidney graft survival rates were 64 ± 6% and 81 ± 5% at 5 years, respectively (median follow-up, 47 months). Multivariable analyses revealed three independent risk factors affecting patient survival: hepatitis C virus positive (HCV+, hazard ratio [HR] 2.9, 95% confidence interval [CI] 1.1-7.9), panel reactive antibody (PRA) > 20% (HR 2.8, 95% CI 1.1-7.2) and female donor gender (HR 2.9, 95% CI 1.1-7.9). For death-censored kidney graft survival, delayed graft function was the strongest negative predictor (HR 8.3, 95% CI 2.5-27.9), followed by HCV+ and PRA > 20%. The adjusted risk of death-censored kidney graft loss in HCV+ SLKT patients was 5.8 (95% CI 1.6-21.6) compared with HCV+ KTA (p = 0.008). Recurrent HCV within 1 year after SLKT correlated with early kidney graft failure (p = 0.004). Careful donor/recipient selection and innovative approaches for HCV+ SLKT patients are critical to further improve long-term outcomes.

Combined liver-kidney transplantation is preferable to liver transplant alone for cirrhotic patients with renal failure

BACKGROUND

The role of combined liver-kidney transplantation (CLKT) for cirrhotic patients with renal failure (RF) is controversial. Since the model for end-stage liver disease era, there has been a rise in the number of CLKT. Using the Organ Procurement Transplant Network/United Network for Organ Sharing database, this study was undertaken to compare outcomes of cirrhotic patients with RF who received either liver transplant alone (LTA) or CLKT between 2002 and 2008.

METHODS

Analysis was limited to cirrhotic patients 18 years old or older, with serum creatinine level 2.5 mg/dL or higher at the time of orthotopic liver transplantation (OLT) or who received dialysis at least twice during the week before OLT. Patients who received CLKT were categorized based on the cause of their underlying RF.

RESULTS

Overall liver allograft and patient survival rates of LTA patients were significantly lower compared with CLKT patients (P<0.001). CLKT patients with hepatorenal syndrome showed significantly higher patient and liver allograft survival rates. Liver allograft survival was superior among CLKT patients irrespective of whether they received dialysis. Prevalence of posttransplantation RF was higher for LTA patients at 6 months and 3 years of follow-up (P<0.001). LTA was a significant risk factor both for graft loss and mortality. Recipient hepatitis C virus seropositivity, donor age, donor cause of death, and life support at the time of OLT were also risk factors for graft loss and death.

CONCLUSIONS

Cirrhotic patients with RF, in particular with hepatorenal syndrome, CLKT is preferable to LTA because it improves liver allograft and patient survival.

Downgrading MELD improves the outcomes after liver transplantation in patients with acute-on-chronic hepatitis B liver failure

Background

High score of model for end-stage liver diseases (MELD) before liver transplantation (LT) indicates poor prognosis. Artificial liver support system (ALSS) has been proved to effectively improve liver and kidney functions, and thus reduce the MELD score. We aim to evaluate whether downgrading MELD score could improve patient survival after LT.

Methodology/Principal Findings

One hundred and twenty-six LT candidates with acute-on-chronic hepatitis B liver failure and MELD score ≥30 were included in this prospective study. Of the 126 patients, 42 received emergency LT within 72 h (ELT group) and the other 84 were given ALSS as salvage treatment. Of the 84 patients, 33 were found to have reduced MELD score (<30) on the day of LT (DGM group), 51 underwent LT with persistent high MELD score (N-DGM group). The median waiting time for a donor was 10 for DGM group and 9.5 days for N-DGM group. In N-DGM group there is a significantly higher overall mortality (43.1%) than that in ELT group (16.7%) and DGM group (15.2%). N-DGM (vs. ECT and DGM) was the only independent risk factor of overall mortality (P = 0.003). Age >40 years and the interval from last ALSS to LT >48 h were independent negative influence factors of downgrading MELD.

Conclusions/Significance

Downgrading MELD for liver transplant candidates with MELD score ≥30 was effective in improving patient prognosis. An appropriate ALSS treatment within 48 h prior to LT is potentially beneficial.

Simultaneous liver and kidney transplants: optimizing use of this double resource

Simultaneous liver and kidney transplantation is a life saving procedure for patients with combined liver and kidney failure; however, it remains controversial because of the need to balance individual patient need versus resource allocation. As waiting lists for transplantation become longer and patients become increasingly ill, there will be greater numbers of patients referred for liver and kidney transplantation. Acute kidney injury even requiring dialysis may potentially be reversible making combined transplant decisions difficult. Similarly, selected compensated cirrhotic patients with renal failure may be managed with renal transplant alone. Shared multicenter experience or clinical trials or both will be required to refine our ability to optimally manage these patients with combined liver and kidney dysfunction.

Preditores de injúria renal aguda em pacientes submetidos ao transplante ortotópico de fígado convencional sem desvio venovenoso

RADICAL: Injúria renal aguda é uma das complicações mais comuns do transplante ortotópico de fígado. A ausência de critério universal para sua definição nestas condições dificulta as comparações entre os estudos. A técnica convencional para o transplante consiste na excisão total da veia cava inferior retro-hepática durante a hepatectomia nativa. Controvérsias sobre o efeito da técnica convencional sem desvio venovenoso na função renal continuam. OBJETIVO: Estimar a incidência e os fatores de risco de injúria renal aguda entre os receptores de transplante ortotópico de fígado convencional sem desvio venovenoso. MÉTODOS: Foram avaliados 375 pacientes submetidos a transplante ortotópico de fígado. Foram analisadas as variáveis pré, intra e pós-operatórias em 153 pacientes submetidos a transplante ortotópico de fígado convencional sem desvio venovenoso. O critério para a injúria renal aguda foi valor da creatinina sérica > 1,5 mg/dl ou débito urinário < 500 ml/24h dentro dos primeiros três dias pós-transplante. Foi realizada análise univariada e multivariada por regressão logística. RESULTADOS: Todos os transplantes foram realizados com enxerto de doador falecido. Sessenta pacientes (39,2%) apresentaram injúria renal aguda. Idade, índice de massa corpórea, escore de Child-Turcotte-Pugh, ureia, hipertensão arterial sistêmica e creatinina sérica pré-operatória apresentaram maiores valores no grupo injúria renal aguda. Durante o período intraoperatório, o grupo injúria renal aguda apresentou mais síndrome de reperfusão, transfusão de concentrado de hemácias, plasma fresco e plaquetas. No pós-operatório, o tempo de permanência em ventilação mecânica e creatinina pós-operatória também foram variáveis, com diferenças significativas para o grupo injúria renal aguda. Após regressão logística, a síndrome de reperfusão, a classe C do Child-Turcotte-Pugh e a creatinina sérica pós-operatória apresentaram diferenças. CONCLUSÃO: Injúria renal aguda após transplante ortotópico de fígado convencional sem desvio venovenoso é uma desordem comum, mas apresenta bom prognóstico. Síndrome de reperfusão, creatinina sérica no pós-operatório e Child C são fatores associados a injúria renal aguda pós-transplante ortotópico de fígado convencional sem desvio venovenoso.