Impact of MELD Score-Based Organ Allocation on Mortality, Bleeding, and Transfusion in Liver Transplantation: A Before-and-After Observational Cohort Study

Perioperative clinical practice in liver transplantation: a cross-sectional survey

PURPOSE

The objective of this study was to describe some components of the perioperative practice in liver transplantation as reported by clinicians.

METHODS

We conducted a cross-sectional clinical practice survey using an online instrument containing questions on selected themes related to the perioperative care of liver transplant recipients. We sent email invitations to Canadian anesthesiologists, Canadian surgeons, and French anesthesiologists specialized in liver transplantation. We used five-point Likert-type scales (from "never" to "always") and numerical or categorical answers. Results are presented as medians or proportions.

RESULTS

We obtained answers from 130 participants (estimated response rate of 71% in Canada and 26% in France). Respondents reported rarely using transesophageal echocardiography routinely but often using it for hemodynamic instability, often using an intraoperative goal-directed hemodynamic management strategy, and never using a phlebotomy (medians from ordinal scales). Fifty-nine percent of respondents reported using a restrictive fluid management strategy to manage hemodynamic instability during the dissection phase. Forty-two percent and 15% of respondents reported using viscoelastic tests to guide intraoperative and postoperative transfusions, respectively. Fifty-four percent of respondents reported not pre-emptively treating preoperative coagulations disturbances, and 91% reported treating them intraoperatively only when bleeding was significant. Most respondents (48-64%) did not have an opinion on the maximal graft ischemic times. Forty-seven percent of respondents reported that a piggyback technique was the preferred vena cava anastomosis approach.

CONCLUSION

Different interventions were reported to be used regarding most components of perioperative care in liver transplantation. Our results suggest that significant equipoise exists on the optimal perioperative management of this population.

Validation of 5 models predicting transfusion, bleeding, and mortality in liver transplantation: an observational cohort study

BACKGROUND

Historically, orthotopic liver transplantation (OLT) has been associated with massive blood loss, blood transfusion and morbidity. In order to predict such outcomes five nomograms have been published relating to transfusions and morbidity associated with OLTs. These nomograms, developed on the basis of three cohorts of patients consisting of 406, 750, and 800 having undergone OLTs, aimed to predict a transfusion of ≥1 red blood cell unit (RBC), a transfusion of >2 RBC units, a blood loss of >900 ml, as well as one-month and one-year survival rates. The aim of this study was to validate these five nomograms in a contemporary, independent cohort of patients.

METHODS

Five nomograms were previously developed based on 406, 750, and 800 OLTs. In this study we performed a temporal validation of these nomograms on contemporary patients that consisted of three cohorts of 800, 250, and 200 OLTs. Logistic regression coefficients from the historic development cohorts were applied to the three contemporary temporal validation cohorts.

RESULTS

The most accurate nomogram was able to predict transfusion of ≥1 RBC units with an area under the curve (AUC) was 0.91. The second-best nomogram was able to predict bleeding of >900 ml with an AUC of 0.70. T he AUC of the third nomogram (transfusion of >2 RBC units) was 0.70. However, is temporal validation was suboptimal, due to a low prevalence of OLTs transfused with >2 RBC units. The last 2 nomograms exhibited clearly suboptimal AUC values of 0.54 and 0.61.

CONCLUSION

Two of the five nomograms predict blood transfusion and blood loss with excellent accuracy. Transfusion of ≥1 RBC unit and blood loss of >900 ml can be predicted on the basis of these nomograms. However, these nomograms are not accurate to predict one-month and one-year survival rates. These results should be further cross-validated, ideally prospectively, in additional external independent cohorts.

Intraoperative phlebotomies and bleeding in liver transplantation: a historical cohort study and causal analysis

BACKGROUND

Liver transplantation is associated with major bleeding and red blood cell (RBC) transfusions. No well-designed causal analysis on interventions used to reduce transfusions, such as an intraoperative phlebotomy, has been conducted in this population.

METHODS

We conducted a historical cohort study among liver transplantations performed from July 2008 to January 2021 in a Canadian centre. The exposure was intraoperative phlebotomy. The outcomes were blood loss, perioperative RBC transfusions (intraoperative and up to 48 hr after surgery), intraoperative RBC transfusions, and one-year survival. We estimated marginal multiplicative factors (MFs), risk differences (RDs), and hazard ratios by inverse probability of treatment weighting both among treated patients and the whole population. Estimates are reported with 95% confidence intervals (CIs).

RESULTS

We included 679 patients undergoing liver transplantations of which 365 (54%) received an intraoperative phlebotomy. A phlebotomy did not reduce bleeding, transfusion risks, or mortality when estimated among the treated but reduced bleeding and transfusion risks when estimated among the whole population (MF, 0.85; 95% CI, 0.72 to 0.99; perioperative RD, -15.2%; 95% CI, -26.1 to -0.8; intraoperative RD, -14.7%; 95% CI, -23.2 to -2.8). In a subgroup analysis on 584 patients with end-stage liver disease, slightly larger effects were observed on both transfusion risks when estimated among the whole population while beneficial effects were observed on the intraoperative transfusion risk when estimated among the treated population.

CONCLUSION

The use of intraoperative phlebotomy was not consistently associated with better outcomes in all targets of inference but may improve outcomes among the whole population.

STUDY REGISTRATION

www.

CLINICALTRIALS

gov (NCT04826666); registered 1 April 2021.

Association of Phlebotomy on Blood Product Transfusion Requirements During Liver Transplantation: An Observational Cohort Study on 1000 Cases

Background

During the past 2 decades, transfusion requirements have decreased drastically during orthotopic liver transplantation (OLT), and transfusion-free transplantation is nowadays increasingly common. Understanding that liberal intravenous volume loading in cirrhotic patients may have detrimental consequences is key. In contrast, phlebotomy is a method to lower central venous pressure and portal venous pressure. The objective of this study was to determine the effectiveness and safety of phlebotomy in the early phase of blood transfusion, blood loss, renal function, and mortality.

Methods

The present study evaluated the impact of phlebotomy on bleeding, transfusion rate, renal dysfunction, and mortality in 1000 consecutive OLTs. Two groups were defined and compared using phlebotomy. Multivariate logistic and linear regression models were used to determine predictors of bleeding, red blood cell (RBC) transfusion, renal dysfunction, and mortality.

Results

A mean of 0.7 ± 1.5 RBC units was transfused per patient for 1000 OLTs, 75% did not receive any RBCs, and the median and interquartile range (25-75) were 0 for all blood products transfused. The phlebotomy was associated with decreased transfusion (RBCs, plasma, platelets, cryoprecipitate, albumin), with less bleeding, and with an increased survival rate, both 1 mo and 1 y. Phlebotomy was not associated with renal dysfunction.

Conclusions

The practice of phlebotomy to lower portal venous pressure was associated with reduced blood product transfusions and blood loss during liver dissection without deleterious effect on renal function.

Comparison of Scores for Child-Pugh Criteria and Standard and Modified Models for End-Stage Liver Disease to Assess Cardiac Hepatopathy in Heart Transplant Recipients

OBJECTIVES

Congestive hepatopathy as a result of advanced heart failure correlates with poor outcomes. Thus, risk-scoring systems have been established to assess the risks for cardiac surgery and hearttransplant, although these systems were originally designed to measure mortality risk in patients with end-stage liver disease. We compared the scores for the Child-Pugh criteria andstandardandmodifiedModels for End-Stage LiverDisease to evaluate the effect of preoperative liver dysfunction on postoperative outcomes inpatients with heart failure who underwent heart transplant.

MATERIALS AND METHODS

Data of 60 consecutive patients who underwent orthotopic heart transplant were analyzed from a historical cohort study from January 1, 2015, to December 31, 2018. We calculated the scores for Child-Pugh criteria and the standard and modified Models for End-Stage Liver Disease.

RESULTS

Of the 60 total patients, 48 were male patients, with a median age of 43 years (range, 13-69 years). Twenty patients died before the end of the study. The causes of death were cardiac, liver, and renal diseases. The mortality risk increased 25% (interquartile range, 0.05-0.51) for the patients with 1 point higher score compared with the patients with 1 point lower score based on a modified Model for End-Stage Liver Disease (P = .01).

CONCLUSIONS

Preoperative liver dysfunction has a significant effect on patient survival. The modified Modelfor End-Stage LiverDisease scoring system could be an effective predictor of perioperative risk stratification for patients with congestive hepatopathy who are undergoing cardiac transplant.

Impact of Model for End-Stage Liver Disease allocation system on outcomes of deceased donor liver transplantation: A single-center experience

Backgrounds/Aims

From June of 2016, the Model for End-Stage Liver Disease (MELD)-based allocation system replaced the Child- Turcotte-Pugh (CTP) score-based system for organ allocation liver in Korea. The aim of this study was to analyze changes in outcomes and arising issues before and after the implementation of the MELD system.

Methods

From June 2014 to June 2018, 129 patients were selected from recipients who underwent deceased donor liver transplantation (DDLT) in Seoul National University Hospital. Pediatric cases were excluded. According to the allocation system, patients were divided into two groups (52 in the MELD group and 77 in the CTP group).

Results

MELD scores of the two groups differed significantly (37.8 ± 2.0 in the MELD group vs. 31.0 ± 8.2 in the CTP group; p = 0.001). The etiology of patients was changed for liver transplantation. The proportion of alcoholic liver cirrhosis increased in the era of the MELD allocation system. However, proportions of hepatitis B related liver cirrhosis and hepatocellular carcinoma were decreased. Six-month mortality rate of the MELD group was 25.0%, which was higher than that (11.7%) of the CTP group (p = 0.022). The 90-day complication rate was significantly higher in the MELD group than in the CTP group (11.5% vs. 2.6%; p = 0.040).

Conclusions

When the MELD allocation system was used to distribute livers to severely ill patients, it resulted in poorer outcomes after surgery and higher proportion of alcoholic cirrhosis. Thus, it is necessary to adjust the MELD allocation system so that outcomes after DDLT could be improved.

Association between intraoperative fluid balance, vasopressors and graft complications in liver transplantation: A cohort study

Introduction

Biliary complications following liver transplantation are common. The effect of intraoperative fluid balance and vasopressors on these complications is unknown.

Materials and methods

We conducted a cohort study between July 2008 and December 2017. Our exposure variables were the total intraoperative fluid balance and the use of vasopressors on ICU admission. Our primary outcome was any biliary complication (anastomotic and non-anastomotic strictures) up to one year after transplantation. Our secondary outcomes were vascular complications, primary graft non-function and survival.

Results

We included 562 consecutive liver transplantations. 192 (34%) transplants had a biliary complication, 167 (30%) had an anastomotic stricture and 56 had a non-anastomotic stricture (10%). We did not observe any effect of intraoperative fluid balance or vasopressor on biliary complications (HR = 0.97; 95% CI, 0.93 to 1.02). A higher intraoperative fluid balance was associated with an increased risk of primary graft non-function (non-linear) and a lower survival (HR = 1.40, 95% CI, 1.14 to 1.71) in multivariable analyses.

Conclusion

Intraoperative fluid balance and vasopressors upon ICU admission were not associated with biliary complications after liver transplantation but may be associated with other adverse events. Intraoperative hemodynamic management must be prospectively studied to further assess their impact on liver recipients’ outcomes.

The Impact of Intraoperative Donor Blood on Packed Red Blood Cell Transfusion During Deceased Donor Liver Transplantation: A Retrospective Cohort Study

BACKGROUND

Blood from deceased organ donors, also known as donor blood (DB), has the potential to reduce the need for packed red blood cells (PRBCs) during liver transplantation (LT). We hypothesized that DB removed during organ procurement is a viable resource that could reduce the need for PRBCs during LT.

METHODS

We retrospectively examined data on LT recipients aged over 18 y who underwent a deceased donor LT. The primary aim was to compare the incidence of PRBC transfusion in LT patients who received intraoperative DB (the DB group) to those who did not (the nondonor blood [NDB] group).

RESULTS

After a propensity score matching process, 175 patients received DB and 175 did not. The median (first-third quartile) volume of DB transfused was 690.0 mL (500.0-900.0), equivalent to a median of 3.1 units (2.3-4.1). More patients in the NDB group received an intraoperative PRBC transfusion than in the DB group: 74.3% (95% confidence intervals, 67.8-80.8) compared with 60% (95% confidence intervals, 52.7-67.3); P = 0.004. The median number of PRBCs transfused intraoperatively was higher in the NDB group compared with the DB group: 3 units (0-6) compared with 2 units (0-4); P = 0.004. There were no significant differences observed in the secondary outcomes.

CONCLUSIONS

Use of DB removed during organ procurement and reinfused to the recipient is a viable resource for reducing the requirements for PRBCs during LT. Use of DB minimizes the exposure of the recipient to multiple donor sources.

Changes in the allocation policy for deceased donor livers in Korea: perspectives from anesthesiologists

Background

The allocation policy for deceased donor livers in Korea was changed in June 2016 from Child-Turcotte-Pugh (CTP) scoring system-based to Model for End-stage Liver Disease (MELD) scoring system-based. Thus, it is necessary to review the effect of allocation policy changes on anesthetic management.

Methods

Medical records of deceased donor liver transplantation (DDLT) from December 2014 to May 2017 were reviewed. We compared the perioperative parameters before and after the change in allocation policy.

Results

Thirty-seven patients underwent DDLT from December 2014 to May 2016 (CTP group), and 42 patients underwent DDLT from June 2016 to May 2017 (MELD group). The MELD score was significantly higher in the MELD group than in the CTP group (36.5 ± 4.6 vs. 26.5 ± 9.4, P < 0.001). The incidence of hepatorenal syndrome was higher in the MELD group than in the CTP group (26 vs. 7, P < 0.001). Packed red blood cell transfusion occurred more frequently in the MELD group than in the CTP group (5.0 ± 3.6 units vs. 3.4 ± 2.2 units, P = 0.025). However, intraoperative bleeding, vasopressor support, and postoperative outcomes were not different between the two groups.

Conclusions

Even though the patient’s objective condition deteriorated, perioperative parameters did not change significantly.

Effects of Intraoperative Fluid Balance During Liver Transplantation on Postoperative Acute Kidney Injury: An Observational Cohort Study

BACKGROUND

Liver transplant recipients suffer many postoperative complications. Few studies evaluated the effects of fluid management on these complications. We conducted an observational cohort study to evaluate the association between intraoperative fluid balance and postoperative acute kidney injury (AKI) and other postoperative complications.

METHODS

We included consecutive adult liver transplant recipients who had their surgery between July 2008 and December 2017. Our exposure was intraoperative fluid balance, and our primary outcome was the grade of AKI at 48 hours after surgery. Our secondary outcomes were the grade of AKI at 7 days, the need for postoperative renal replacement therapy, postoperative red blood cell transfusions, time to first extubation, time to discharge from the intensive care unit (ICU), and 1-year survival. Every analysis was adjusted for potential confounders.

RESULTS

We included 532 transplantations in 492 patients. We observed no effect of fluid balance on either 48-hour AKI, 7-day AKI, or on the need for postoperative renal replacement therapy after adjustments for confounders. A higher fluid balance increased the time to ICU discharge, and increased the risk of dying (hazard ratio = 1.21 [1.04,1.40]).

CONCLUSIONS

We observed no association between intraoperative fluid balance and postoperative AKI. Fluid balance was associated with longer time to ICU discharge and lower survival. This study provides insight that might inform the design of a clinical trial on fluid management strategies in this population.

Effects of intraoperative hemodynamic management on postoperative acute kidney injury in liver transplantation: An observational cohort study

Background

Intraoperative restrictive fluid management strategies might improve postoperative outcomes in liver transplantation. Effects of vasopressors within any hemodynamic management strategy are unclear.

Methods

We conducted an observational cohort study on adult liver transplant recipients between July 2008 and December 2017. We measured the effect of vasopressors infused at admission in the intensive care unit (ICU) and total intraoperative fluid balance. Our primary outcome was 48-hour acute kidney injury (AKI) and our secondary outcomes were 7-day AKI, need for postoperative renal replacement therapy (RRT), time to extubation in the ICU, time to ICU discharge and survival up to 1 year. We fitted models adjusted for confounders using generalized estimating equations or survival models using robust standard errors. We reported results with 95% confidence intervals.

Results

We included 532 patients. Vasopressors use was not associated with 48-hour or 7-day AKI but modified the effects of fluid balance on RRT and mortality. A higher fluid balance was associated with a higher need for RRT (OR = 1.52 [1.15, 2.01], p<0.001 for interaction) and lower survival (HR = 1.71 [1.26, 2.34], p<0.01 for interaction) only among patients without vasopressors. In patients with vasopressors, higher doses of vasopressors were associated with a higher mortality (HR = 1.29 [1.13, 1.49] per 10 μg/min of norepinephrine).

Conclusion

The presence of any vasopressor at the end of surgery was not associated with AKI or RRT. The use of vasopressors might modify the harmful association between fluid balance and other postoperative outcomes. The liberal use of vasopressors to implement a restrictive fluid management strategy deserves further investigation.

Restrictive fluid management strategies and outcomes in liver transplantation: a systematic review

PURPOSE

Restrictive fluid management strategies have been proposed to reduce complications in liver transplant recipients. We conducted a systematic review to evaluate the effects of restrictive perioperative fluid management strategies, compared with liberal ones, on postoperative outcomes in adult liver transplant recipients. Our primary outcome was acute kidney injury (AKI). Our secondary outcomes were bleeding, mortality, and other postoperative complications.

SOURCE

We searched major databases (CINAHL, EMB Reviews, EMBASE, MEDLINE, and the grey literature) from their inception to 10 July 2018 for randomized-controlled trials (RCTs) and observational studies comparing two fluid management strategies (or observational studies reporting two outcomes with available data on fluid volume received) in adult liver transplant recipients. Study selection, data abstraction, and risk of bias assessment were performed by at least two investigators. Data from RCTs were pooled using risk ratios (RR) and mean differences (MD) with random-effect models.

PRINCIPAL FINDINGS

We found seven RCTs and 29 observational studies. Based on RCTs, fluid management strategies did not have any effect on AKI, mortality, or any other postoperative complications. Intraoperative RCTs suggested that a restrictive fluid management strategy reduced pulmonary complications (RR, 0.69; 95% confidence interval [CI], 0.47 to 0.99; n = 283; I² = 27%), duration of mechanical ventilation (MD, -13.04 hr; 95% CI, -22.2 to -3.88; n = 130; I² = 0%) and blood loss (MD, -1.14 L; 95% CI, -1.72 to -0.57; n = 151; I² = 0%).

CONCLUSION

Based on low or very low levels of evidence, we did not find any association between restrictive fluid management strategies and AKI, but we observed possible protective effects of intraoperative restrictive fluid management strategies on other outcomes.

TRIAL REGISTRATION

PROSPERO (CRD42017054970); registered 18 May, 2017.