Intraoperative Hemodynamic Parameters and Acute Kidney Injury After Living Donor Liver Transplantation

Renal Replacement Therapy in Cirrhosis: A Contemporary Review

Acute kidney injury is a common complication of decompensated cirrhosis, frequently requires hospitalization, and carries a high short-term mortality. This population experiences several characteristic types of acute kidney injury: hypovolemic-mediated (prerenal), ischemic/nephrotoxic-mediated (acute-tubular necrosis), and hepatorenal syndrome. Prerenal acute kidney injury is treated with volume resuscitation. Acute-tubular necrosis is treated by optimizing perfusion pressure and discontinuing the offending agent. Hepatorenal syndrome, a unique physiology of decreased effective arterial circulation leading to renal vasoconstriction and ultimately acute kidney injury, is treated with plasma expansion with albumin and splanchnic vasoconstrictors such as terlipressin or norepinephrine. Common acute stressors such as bleeding, infection, and volume depletion often contribute to multifactorial acute kidney injury. Even with optimal medical management, many clinicians are faced with the challenge of initiating renal replacement therapy in these patients. This article reviews the epidemiology, indications, and complex considerations of renal replacement therapy for acute kidney injury in decompensated cirrhosis.

Pulmonary artery catheter monitoring versus arterial waveform-based monitoring during liver transplantation: a retrospective cohort study

Although pulmonary artery catheter (PAC) has been used during liver transplantation surgery, the usefulness of PAC has rarely been investigated. We evaluated whether the use of PAC is associated with better clinical outcomes compared to arterial waveform-based monitoring after liver transplantation. A total of 1565 cases undergoing liver transplantation were reviewed. We determined whether patients received PAC or not and divided our cohort into the PAC with hemodynamic monitoring using PAC and the non-PAC with arterial waveform-based monitoring using FloTrac-Vigileo. Propensity score matching was performed. Acute kidney injury (AKI), early allograft dysfunction (EAD) and 1-year all-cause mortality or graft failure were compared in the matched cohorts. Logistic regression analysis was performed in the inverse probability of treatment-weighted (IPTW) cohort for postoperative EAD and AKI, respectively. Five-year overall survival was compared between the two groups. In the matched cohort, there was no significant difference in the incidence of AKI, EAD, length of hospital or ICU stay, and 1-year all-cause mortality between the groups. In the IPTW cohort, the use of PAC was not a significant predictor for AKI or EAD (AKI: odds ratio (95% confidence interval) of 1.20 (0.47-1.56), p = 0.229; EAD: 0.99 (0.38-1.14), p = 0.323). There was no significant difference in the survival between groups after propensity score matching (Log-rank test p = 0.578). In conclusion, posttransplant clinical outcomes were not significantly different between the groups with and without PAC. Anesthetic management without the use of PAC may be possible in low-risk patients during liver transplantation. The risk should be carefully assessed by considering MELD scores, ischemic time, surgical history, previous treatment of underlying liver disease, and degree of portal and pulmonary hypertension.Registration: https://clinicaltrials.gov/ct2/show/NCT05457114 (registration date: July 15, 2022).

Intraoperative hypotension and the risk of acute kidney injury following liver transplantation

BACKGROUND

Acute kidney injury (AKI) is a frequent adverse outcome following liver transplantation (LT) with a multifactorial etiology. It is critical to identify modifiable risk factors to mitigate the risk. One key area of interest is the role of intraoperative hypotension, which remains relatively unexplored in liver transplant cohorts.

METHODS

This was a retrospective observational cohort study of 1292 adult patients who underwent LT (between 2009 and 2019). Multivariable logistic regression analysis was used to explore the association between intraoperative hypotension, quantified by time duration (in min) under various mean arterial pressure (MAP) thresholds, and the primary outcome of early postoperative AKI according to the KDIGO criteria.

RESULTS

AKI occurred in 40% of patients and was independently associated with greater than 20 min spent below MAP thresholds of 55 mm Hg (adjusted OR = 1.866; 95% CI = 1.037-3.44; P = 0.041) and 50 mm Hg (adjusted OR = 1.801; 95% CI = 1.087-2.992; P = 0.023). Further sensitivity analyses demonstrated that the association between intraoperative hypotension and postoperative AKI was accentuated after restricting the analysis to patients with a normal preoperative renal function.

CONCLUSIONS

Prolonged (>20 min) intraoperative hypotension (below a MAP of 55 mm Hg) was independently associated with AKI following LT, after adjusting for several known confounders.

Serum neutrophil gelatinase-associated lipocalin and lactate level during surgery predict acute kidney injury and early allograft dysfunction after liver transplantation

Early allograft dysfunction (EAD) and acute kidney injury (AKI) are common and clinically important complications after liver transplantation. Serum lactate level at the end of surgery could predict EAD and neutrophil gelatinase-associated lipocalin (NGAL) is known as a biomarker for AKI after liver transplantation. The authors investigated whether the combination of these two laboratory tests could be used as an early predictor of these two complications of EAD and AKI. We reviewed cases undergoing living donor liver transplantation (n = 353). Lactate-adjusted NGAL level, a combination of these two predictors, was calculated as the sum of each value multiplied by the odds ratio for EAD or AKI. We evaluated whether this combined predictor at the end of surgery is significantly associated with both postoperative AKI or EAD. We compared the area under the receiver operating characteristic curve (AUC) between our multivariable regression models with and without NGAL, lactate, or lactate-adjusted NGAL. NGAL, lactate and lactate-adjusted NGAL are significant predictors for EAD and AKI. The regression model for EAD or AKI including lactate-adjusted NGAL showed a greater AUC (for EAD: odds ratio [OR] 0.88, 95% confidence interval [CI] 0.84-0.91; for AKI: OR 0.89, 95% CI 0.85-0.92) compared to the AUC of the models including lactate (for EAD: OR 0.84, 95% CI 0.81-0.88; for AKI: OR 0.79, 95% CI 0.74-0.83) or NGAL alone (for EAD: OR 0.82, 95% CI 0.77-0.86; for AKI: OR 0.84, 95% CI 0.80-0.88) or the model without lactate or NGAL (for EAD: OR 0.64, 95% CI 0.58-0.69, for AKI: OR 0.75, 95% CI 0.70-0.79). In conclusion, lactate-adjusted NGAL level at the end of surgery could be a reliable combined laboratory predictor for postoperative EAD or AKI after liver transplantation with a greater discriminative ability than lactate or NGAL alone.

Impact of Advanced Renal Dysfunction on Posttransplant Outcomes After Living Donor Liver Transplantation in the United States

BACKGROUND

Survival after living donor liver transplantation (LDLT) in the United States is excellent. However, the significance of pretransplant kidney disease on outcomes in this population is poorly understood.

METHODS

This was a retrospective cohort study of 2806 LDLT recipients nationally between January 2010 and June 2020. Recipients with estimated glomerular filtration rate <40 mL/min/1.73 m2 (eGFR-low) or requiring dialysis were compared. Multivariable survival analyses evaluated (1) eGFR-low as a predictor of post-LDLT survival and (2) the survival of LDLT versus deceased donor liver transplant (DDLT) alone with eGFR-low.

RESULTS

From 2010 to 2020, 140 (5.0%) patients had eGFR-low and 18 (0.6%) required dialysis pre-LDLT. The number of LDLTs requiring dialysis between 2017 and 2020 outnumbered the prior 7 y. Overall LDLT experience was greater at centers performing LDLT in recipients with renal dysfunction (P < 0.001). LDLT recipients with eGFR-low had longstanding renal dysfunction: mean eGFR 3-6 mo before LDLT 42.7 (±15.1) mL/min/1.73 m2. Nearly half (5/12) of eGFR-low recipients with active kidney transplant (KT) listing at LDLT experienced renal recovery. Five patients underwent early KT after LDLT via the new "safety net" policy. Unadjusted survival after LDLT was worse with eGFR-low (hazard ratio 2.12 versus eGFR ≥40 mL/min/1.73 m2; 95% confidence interval, 1.47-3.05; P < 0.001), but no longer so when accounting for mean eGFR 3-6 mo pre-LDLT (hazard ratio, 1.27; 95% confidence interval, 0.82-1.95; P = 0.3). The adjusted survival of patients with eGFR-low receiving LDLT versus deceased donor liver transplant alone was not different (P = 0.08).

CONCLUSIONS

Overall, outcomes after LDLT with advanced renal dysfunction are acceptable. These findings are relevant given the recent "safety net" KT policy.

The Prognostic Role of Right Ventricular Stroke Work Index during Liver Transplantation

Right heart-associated hemodynamic parameters including intraoperative pulmonary vascular resistance (PVR) were reported to be associated with patient survival after liver transplantation. We investigated whether intraoperative stroke work indexes of both ventricles could have a better prognostic value than PVR. We reviewed 683 cases at a tertiary care academic medical center. We collected intraoperative variables of baseline central venous pressure, baseline right ventricle end-diastolic volume, mixed venous oxygen saturation, intraoperative PVR and right and left ventricular stroke work indexes. Time-weighted means or area under the curve of intraoperative right and left ventricular stroke work indexes were calculated as exposure variables. One-year all-cause mortality or graft failure was our primary outcome. Cox proportional hazard regression analysis was performed to evaluate the association between exposure variables and one-year all-cause mortality or graft failure. Kaplan–Meier survival curve analysis of our primary outcome was performed for different time-weighted mean ventricular stroke work index groups. Cubic spline curve analysis was performed to evaluate the linear relationship between our exposure variables and primary outcome. Time-weighted mean right ventricular stroke work index was significantly associated with one-year all-cause mortality or graft failure (hazard ratio 1.21, 95% confidence interval (CI) 1.12–1.36, p < 0.001). However, there was no significant association between time-weighted mean left ventricular stroke work index, time-weighted mean PVR, PVR at the end of surgery and one-year mortality. Area under the curve of right ventricular stroke work index was also significantly associated with one-year mortality or graft failure (hazard ratio 1.24, 95% CI 1.15–1.37, p < 0.001). Kaplan–Meier survival curve analysis showed a significant difference in the survival between different mean right ventricular stroke work index groups (Log-rank test: p = 0.002). Cubic spline function curve showed the gradual increase in the risk of mortality with a positive slope with time-weighted mean right ventricular stroke work index. In conclusion, intraoperative elevated right ventricular stroke work index was significantly associated with poor patient or graft survival after liver transplantation. Intraoperative right ventricular stroke work index could be an intraoperative hemodynamic goal and prognostic marker for mortality after liver transplantation.

Perioperative ABO Blood Group Isoagglutinin Titer and the Risk of Acute Kidney Injury after ABO-Incompatible Living Donor Liver Transplantation

For ABO-incompatible liver transplantation (ABO-i LT), therapeutic plasma exchange (TPE) is performed preoperatively to reduce the isoagglutinin titer of anti-ABO blood type antibodies. We evaluated whether perioperative high isoagglutinin titer is associated with postoperative risk of acute kidney injury (AKI). In 130 cases of ABO-i LT, we collected immunoglobulin (Ig) G and Ig M isoagglutinin titers of baseline, pre-LT, and postoperative peak values. These values were compared between the patients with and without postoperative AKI. Multivariable logistic regression analysis was used to evaluate the association between perioperative isoagglutinin titers and postoperative AKI. Clinical and graft-related outcomes were compared between high and low baseline and postoperative peak isoagglutinin groups. The incidence of AKI was 42.3%. Preoperative baseline and postoperative peak isoagglutinin titers of both Ig M and Ig G were significantly higher in the patients with AKI than those without AKI. Multivariable logistic regression analysis showed that preoperative baseline and postoperative peak Ig M isoagglutinin titers were significantly associated with the risk of AKI (baseline: odds ratio 1.06, 95% confidence interval 1.02 to 1.09; postoperative peak: odds ratio 1.08, 95% confidence interval 1.04 to 1.13). Cubic spline function curves show a positive relationship between the baseline and postoperative peak isoagglutinin titers and the risk of AKI. Clinical outcomes other than AKI were not significantly different according to the baseline and postoperative peak isoagglutinin titers. Preoperative high initial and postoperative peak Ig M isoagglutinin titers were significantly associated with the development of AKI. As the causal relationship between high isoagglutinin titers and risk of AKI is unclear, the high baseline and postoperative isoagglutinin titers could be used simply as a warning sign for the risk of AKI after liver transplantation.

Different Severity of Clinical Outcomes Between the 2 Subgroups of Stage 1 Acute Kidney Injury After Liver Transplantation

BACKGROUND

Although the Kidney Disease: Improving Global Outcomes (KDIGO) criteria is used to define acute kidney injury (AKI) after liver transplantation, the criteria was criticized for including 2 heterogeneous groups of different serum creatinine (sCr) criteria together in AKI stage 1. We investigated whether there are significant differences in clinical outcomes between 2 subgroups of patients within AKI stage 1.

METHODS

A total of 1440 cases were reviewed. The AKI stage 1 (n = 443) were divided into 2 subgroups based on changes in sCr level (stage 1a: ≥0.3 mg/dL of absolute sCr increase, n = 251; stage 1b: ≥50% relative sCr increase, n = 192). Propensity score analysis was performed between stage 1a and 1b groups, yielding 157 matched pairs. We compared the length of hospital stay, early allograft dysfunction, and 5-year all-cause mortality between these subgroups after matching. Kaplan-Meier analyses were performed to compare the graft or overall survival between the subgroups after matching. Sensitivity analysis for Acute Kidney Injury Network (AKIN) criteria was performed.

RESULTS

Length of hospital stay and 5-year all-cause mortality was significantly worse in patients with stage 1b compared to stage 1a after matching. Five-year graft or patient survival was significantly worse in patients with stage 1b compared to stage 1a after matching (Log-rank test P = 0.022 and P = 0.027, respectively). These results were the same regarding AKIN criteria.

CONCLUSIONS

The KDIGO criteria for AKI stage 1 could be further divided into 2 substages with different severity of clinical outcomes. This modified criteria could give additional prognostic information in patients undergoing liver transplantation.

Intraoperative hypotension during liver transplant surgery is associated with postoperative acute kidney injury: a historical cohort study

Background

Acute kidney injury (AKI) occurs frequently after liver transplant surgery and is associated with significant morbidity and mortality. While the impact of intraoperative hypotension (IOH) on postoperative AKI has been well demonstrated in patients undergoing a wide variety of non-cardiac surgeries, it remains poorly studied in liver transplant surgery. We tested the hypothesis that IOH is associated with AKI following liver transplant surgery.

Methods

This historical cohort study included all patients who underwent liver transplant surgery between 2014 and 2019 except those with a preoperative creatinine > 1.5 mg/dl and/or who had combined transplantation surgery. IOH was defined as any mean arterial pressure (MAP) < 65 mmHg and was classified according to the percentage of case time during which the MAP was < 65 mmHg into three groups, based on the interquartile range of the study cohort: “short” (Quartile 1, < 8.6% of case time), “intermediate” (Quartiles 2–3, 8.6–39.5%) and “long” (Quartile 4, > 39.5%) duration. AKI stages were classified according to a “modified” “Kidney Disease: Improving Global Outcomes” (KDIGO) criteria. Logistic regression modelling was conducted to assess the association between IOH and postoperative AKI. The model was run both as a univariate and with multiple perioperative covariates to test for robustness to confounders.

Results

Of the 205 patients who met our inclusion criteria, 117 (57.1%) developed AKI. Fifty-two (25%), 102 (50%) and 51 (25%) patients had short, intermediate and long duration of IOH respectively. In multivariate analysis, IOH was independently associated with an increased risk of AKI (adjusted odds ratio [OR] 1.05; 95%CI 1.02–1.09; P < 0.001). Compared to “short duration” of IOH, “intermediate duration” was associated with a 10-fold increased risk of developing AKI (OR 9.7; 95%CI 4.1–22.7; P < 0.001). “Long duration” was associated with an even greater risk of AKI compared to “short duration” (OR 34.6; 95%CI 11.5-108.6; P < 0.001).

Conclusions

Intraoperative hypotension is independently associated with the development of AKI after liver transplant surgery. The longer the MAP is < 65 mmHg, the higher the risk the patient will develop AKI in the immediate postoperative period, and the greater the likely severity. Anesthesiologists and surgeons must therefore make every effort to avoid IOH during surgery.

Intraoperative Oxygen Delivery and Acute Kidney Injury after Liver Transplantation

Although intraoperative hemodynamic variables were reported to be associated with acute kidney injury (AKI) after liver transplantation, the time-dependent association between intraoperative oxygen delivery and AKI has not yet been evaluated. We reviewed 676 cases of liver transplantation. Oxygen delivery index (DO2I) was calculated at least ten times during surgery. AKI was defined according to the Kidney Disease Improving Global Outcomes criteria. The area under the curve (AUC) was calculated as below a DO2I of 300 (AUC < 300), 400 and 500 mL/min/m2 threshold. Also, the cumulative time below a DO2I of 300 (Time < 300), 400, and 500 mL/min/m2 were calculated. Multivariable logistic regression analysis was performed to evaluate whether AUC < 300 or time < 300 was independently associated with the risk of AKI. As a sensitivity analysis, propensity score matching analysis was performed between the two intraoperative mean DO2I groups using a cutoff of 500 ml/min/m2, and the incidence of AKI was compared between the groups. Multivariable analysis showed that AUC < 300 or time < 300 was an independent predictor of AKI (AUC < 300: odds ratio [OR] = 1.10, 95% confidence interval [CI] 1.06-1.13, time < 300: OR = 1.10, 95% CI 1.08-1.14). Propensity score matching yielded 192 pairs of low and high mean DO2I groups. The incidence of overall and stage 2 or 3 AKI was significantly higher in the lower DO2I group compared to the higher group (overall AKI: lower group, n = 64 (33.3%) vs. higher group, n = 106 (55.2%), P < 0.001). In conclusion, there was a significant time-dependent association between the intraoperative poor oxygen delivery <300 mL/min/m2 and the risk of AKI after liver transplantation. The intraoperative optimization of oxygen delivery may mitigate the risk of AKI.

Influence of Transfusion on the Risk of Acute Kidney Injury: ABO-Compatible versus ABO-Incompatible Liver Transplantation

ABO-incompatible liver transplantation (ABO-i LT) is associated with a higher risk of acute kidney injury (AKI) compared to ABO-compatible liver transplantation (ABO-c LT). We compared the risk of AKI associated with transfusion between ABO-c and ABO-i living donor liver transplantation (LDLT). In 885 cases of LDLT, we used a propensity score analysis to match patients who underwent ABO-c (n = 766) and ABO-i (n = 119) LDLT. Baseline medical status, laboratory findings, and surgical- and anesthesia-related parameters were used as contributors for propensity score matching. AKI was defined according to the "Kidney Disease Improving Global Outcomes" criteria. After 1:2 propensity score matching, a conditional logistic regression analysis was performed to evaluate the relationship between the intraoperative transfusion of packed red blood cells (pRBCs) and fresh frozen plasma (FFP) on the risk of AKI. The incidence of AKI was higher in ABO-i LT than in ABO-c LT before and after matching (after matching, 65.8% in ABO-i vs 39.7% in ABO-c, p < 0.001). The incidence of AKI increased in direct proportion to the amount of transfusion, and this increase was more pronounced in ABO-i LT. The risk of pRBC transfusion for AKI was greater in ABO-i LT (multivariable adjusted odds ratio (OR) 1.32 per unit) than in ABO-c LT (OR 1.11 per unit). The risk of FFP transfusion was even greater in ABO-i LT (OR 1.44 per unit) than in ABO-c LT (OR 1.07 per unit). In conclusion, the association between transfusion and risk of AKI was stronger in patients with ABO-i LT than with ABO-c LT. Interventions to reduce perioperative transfusions may attenuate the risk of AKI in patients with ABO-i LT.

Intraoperative Hepatic Blood Inflow Can Predict Early Acute Kidney Injury following DCD Liver Transplantation: A Retrospective Observational Study

Purpose

Acute kidney injury (AKI) is a major and severe complication following donation-after-circulatory-death (DCD) liver transplantation (LT) and is associated with increased postoperative morbidity and mortality. However, the risk factors and the prognosis factors of AKI still need to be further explored, and the relativity of intraoperative hepatic blood inflow (HBI) and AKI following LT has not been discussed yet. The purpose of this study was to investigate the correlation between HBI and AKI and to construct a prediction model of early acute kidney injury (EAKI) following DCD LT with the combination of HBI and other clinical parameters.

Methods

Clinical data of 132 patients who underwent DCD liver transplantation at the first hospital of China Medical University from April 2005 to March 2017 were analyzed. Data of 105 patients (the first ten years of patients) were used to develop the prediction model. Then we assessed the clinical usefulness of the prediction models in the validation cohort (27 patients). EAKI according to Kidney Disease Improving Global Outcomes (KDIGO) criteria based on serum creatinine increase during 7-day of postoperative follow-up.

Results

After Least Absolute Shrinkage and Selection Operator (LASSO) regression and simplification, a simplified prediction model consisting of the Child-Turcotte-Pugh (CTP) score (p=0.033), anhepatic phase (p=0.014), packed red blood cell (pRBC) transfusion (p=0.027), and the HBI indexed by height (HBI/h) (p=0.002) was established. The C-indexes of the model in the development and validation cohort were 0.823 [95% CI, 0.738-0.908] and 0.921 [95% CI, 0.816-1.000], respectively.

Conclusions

In this study, we demonstrated the utility of HBI/h as a predictor for EAKI following DCD LT, as well as the clinical usefulness of the prediction model through the combination of the CTP score, anhepatic phase, pRBC transfusion and HBI/h.