The combination of MELD score and ICG liver testing predicts length of stay in the ICU and hospital mortality in liver transplant recipients

Indocyanine green clearance tests to assess liver transplantation outcomes: a systematic review

BACKGROUND

Liver transplantation (LT) is the gold standard for end-stage liver disease, yet postoperative complications challenge patients and physicians. Indocyanine green (ICG) clearance, a quantitative dynamic test of liver function, is a rapid, reproducible, and reliable test of liver function. This study aimed to systematically review and summarize current literature analyzing the association between ICG tests and post-LT outcomes.

METHODS

This systematic review was conducted according to PRISMA guidelines. MEDLINE and Cochrane Library, as main databases, and other sources were searched until August 2022 to identify articles reporting the prognostic value of postoperative ICG tests associated with outcomes of adult LT recipients.Risk of bias of included articles was assessed using Quality In Prognosis Studies tool. Methodological quality varied from low to high across risk of bias domains.

RESULTS

Six studies conducted between 1994 and 2018 in Europe, America, and Asia were included. The study population ranged from 50 to 332 participants. ICG clearance on the first postoperative day was associated with early allograft dysfunction, graft loss, 1-month and 3-month patient survival probability, prolonged ICU, and hospital stay. The dichotomized ICG plasma disappearance rate (PDR) provided a strong association with medium-term and long-term outcomes: PDR less than 10%/min with 1-month mortality or re-transplantation (odds ratio: 7.89, 95% CI 3.59-17.34, P <0.001) and PDR less than 16.0%/min with 3-month patient survival probability (hazard ratio: 13.90, 95% CI 4.67-41.35, P <0.01). The preoperative model for end-stage liver disease and body mass index were independent prognostic factors for early allograft dysfunction, early complications, and prolonged ICU stay; post-LT prothrombin time and INR were independently associated with graft loss and bilirubin with a prolonged hospital stay.

CONCLUSION

This review shows that ICG clearance tests are associated with graft function recovery, suggesting that a potential prognostic role of ICG test, as an aid in predicting the post-LT course, could be considered.

[Indocyanine green in liver transplantation]

The purpose of this study was to evaluate the first own experience of using indocyanine green (ICG) in liver transplantation compared to literature data and to determine its potential for clinical practice. Liver transplantation is an effective option for patients with end-stage disease, but this procedure is associated with many problems such as graft rejection, graft dysfunction, surgical risk and postoperative management. Modern methods for assessing graft function have their limitations, so a more efficient method is needed. According to this review, ICG fluorescence is valuable for effective intraoperative blood flow control, assessment of graft function, intraoperative and postoperative monitoring of clinical status. ICG fluorescence can also predict clinical status of patients at all stages of liver transplantation. Routine ICG fluorescence method is advisable in liver transplantation to improve outcomes and optimize treatment process.

Prophylactic Perioperative Terlipressin Therapy for Preventing Acute Kidney Injury in Living Donor Liver Transplant Recipients: A Systematic Review and Meta-Analysis

Background

Acute kidney injury (AKI) is common in the perioperative transplant period and is associated with poor outcomes. Few studies reported a reduction in AKI incidence with terlipressin therapy by counteracting the hemodynamic alterations occurring during liver transplantation. However, the effect of terlipressin on posttransplant outcomes has not been systematically reviewed.

Methods

A comprehensive search of electronic databases was performed. Studies reporting the use of terlipressin in the perioperative period of living donor liver transplantation were included. We expressed the dichotomous outcomes as risk ratio (RR, 95% confidence interval [CI]) using the random effects model. The primary aim was to assess the posttransplant risk of AKI. The secondary aims were to assess the need for renal replacement therapy (RRT), vasopressors, effect on hemodynamics, blood loss during surgery, hospital and intensive care unit (ICU) stay, and in-hospital mortality.

Results

A total of nine studies reporting 711 patients (309 patients in the terlipressin group and 402 in the control group) were included for analysis. Terlipressin was administered for a mean duration of 53.44 ± 28.61 h postsurgery. The risk of AKI was lower with terlipressin (0.6 [95% CI, 0.44-0.8]; P = 0.001). However, on sensitivity analysis including only four randomized controlled trials (I² = 0; P = 0.54), the risk of AKI was similar in both the groups (0.7 [0.43-1.09]; P = 0.11). The need for RRT was similar in both the groups (0.75 [0.35-1.56]; P = 0.44). Terlipressin therapy reduced the need for another vasopressor (0.34 [0.25-0.47]; P < 0.001) with a concomitant rise in mean arterial pressure and systemic vascular resistance by 3.2 mm Hg (1.64-4.7; P < 0.001) and 77.64 dyne cm^-1.sec^-5 (21.27-134; P = 0.007), respectively. Blood loss, duration of hospital/ICU stay, and mortality were similar in both groups.

Conclusions

Perioperative terlipressin therapy has no clinically relevant benefit.

Current and Potential Applications for Indocyanine Green in Liver Transplantation

Indocyanine green (ICG) is a fluorescent dye taken up and almost exclusively cleared by the liver. Measurement of its clearance and visualization of its fluorescence make it suitable for a number of potential applications in liver transplantation including assessment of liver function and real-time assessment of arterial, venous, and biliary structures. ICG clearance can be used to assess donor graft quality before procurement and graft metabolic function before transplant using normothermic ex vivo machine perfusion. ICG clearance in the post-liver transplantation period is able to predict recipient outcomes with correlations to early allograft dysfunction and postoperative complications. After absorbing light in the near-infrared spectrum, ICG also emits fluorescence at 835 nm. This allows the assessment of vascular patency after reconstruction and patterns of liver perfusion in real time. ICG perfusion patterns after revascularization are also associated with posttransplant graft function and survival. ICG fluorescence cholangiography is routine in a number of centers and acts as an aid to identifying the optimal point of bile duct division during living donor liver transplantation to optimize safety for both donor and recipient. In summary, ICG is a versatile tool and has a number of useful applications in the liver transplantation journey including assessment of liver function, perfusion assessment, and cholangiography. Further research and clinical trials are required to validate and standardize its routine use in liver transplantation.

Association between the donor to recipient ICG-PDR variation rate and the functional recovery of the graft after orthotopic liver transplantation: A case series

Background

Despite current advances in liver transplant surgery, post-operative early allograft dysfunction still complicates the patient prognosis and graft survival. The transition from the donor has not been yet fully understood, and no study quantifies if and how the liver function changes through its transfer to the recipient. The indocyanine green dye plasma disappearance rate (ICG-PDR) is a simple validated tool of liver function assessment. The variation rate between the donor and recipient ICG-PDR still needs to be investigated.

Materials and methods

Single-center retrospective study. ICG-PDR determinations were performed before graft retrieval (T1) and 24 hours after transplant (T2). The ICG-PDR relative variation rate between T1 and T2 was calculated to assess the graft function and suffering/recovering. Matched data were compared with the MEAF model of graft dysfunction.

Objective

To investigate whether the variation rate between the donor ICG-PDR value and the recipient ICG-PDR measurement on first postoperative day (POD₁) can be associated with the MEAF score.

Results

36 ICG-PDR measurements between 18 donors and 18 graft recipients were performed. The mean donor ICG-PDR was 22.64 (SD 6.35), and the mean receiver’s ICG-PDR on 1st POD was 17.68 (SD 6.60), with a mean MEAF value of 4.51 (SD 1.23). Pearson’s test stressed a good, linear inverse correlation between the ICG-PDR relative variation and the MEAF values, correlation coefficient -0.580 (p = 0.012).

Conclusion

The direct correlation between the donor to recipient ICG-PDR variation rate and MEAF was found. Measurements at T1 and T2 showed an up- or downtrend of the graft performance that reflect the MEAF values.

An evaluation of the safety and preliminary efficacy of peri- and post-operative treprostinil in preventing ischemia and reperfusion injury in adult orthotopic liver transplant recipients

Background

Orthotopic liver transplantation (OLT) is the only treatment option for various end‐stage liver diseases. Ischemia and reperfusion (I/R) injury is one of the unavoidable complications/conditions in OLT. In 2019, a total of 8896 livers were transplanted of which >94% organs were procured from deceased donors. An increase in the use of extended criteria donor (ECD) livers for transplantation further unraveled the role of hepatic I/R injury on short‐term and long‐term graft outcomes. Despite promising outcomes with the use of antioxidants, free radical scavengers, and vasodilators; I/R‐mediated liver injury persists and significantly influences the overall clinical outcomes. Treprostinil, a synthetic prostacyclin I₂ (PGI₂) analog, due to its vasodilatory property, antiplatelet activity, and its ability to downregulate pro‐inflammatory cytokines can potentially minimize I/R injury.

Aim

We investigated the safety and preliminary efficacy of continuous intravenous infusion of treprostinil in liver transplant recipients in a prospective, single‐center, non‐randomized, interventional study.

Material and methods

This was a dose escalation (3 + 3 design) phase 1/2 study. Deceased donor liver transplant recipients received 5 ng/kg/min for two days, or 2.5, 5, and 7.5 ng/min/kg for 5 days as a continuous infusion. Multiple blood samples were collected for biochemical parameter assessment and for measuring treprostinil levels. Indocyanine green plasma disappearance rate was used as a measure of hepatic functional capacity.

Results

Subjects tolerated continuous infusion of treprostinil up to 5 ng/kg/min for 120 h with no occurrence of primary graft non‐function (PNF), minimized need for ventilation support, reduced hospitalization time, 100% graft and patient survival, and improved hepatobiliary excretory function comparable to normal healthy adults.

Discussion

Treprostinil can be administered to liver transplant patients safely during the perioperative period.

Conclusion

Based on this phase 1/2 study, further efficacy studies of treprostinil in preventing I/R injury of liver should be conducted to potentially increase the number of livers available for transplantation.

Development of a scoring tool for predicting prolonged length of hospital stay in peritoneal dialysis patients through data mining

Background

The hospital admission rate is high in patients treated with peritoneal dialysis (PD), and the length of stay (LOS) in the hospital is a key indicator of medical resource allocation. This study aimed to develop a scoring tool for predicting prolonged LOS (pLOS) in PD patients by combining machine learning and traditional logistic regression (LR).

Methods

This study was based on patient data collected using the Hospital Quality Monitoring System (HQMS) in China. Three machine learning methods, classification and regression tree (CART), random forest (RF), and gradient boosting decision tree (GBDT), were used to develop models to predict pLOS, which is longer than the average LOS, in PD patients. The model with the best prediction performance was used to identify predictive factors contributing to the outcome. A multivariate LR model based on the identified predictors was then built to derive the score assigned to each predictor. Finally, a scoring tool was developed, and it was tested by stratifying PD patients into different pLOS risk groups.

Results

A total of 22,859 PD patients were included in our study, with 25.2% having pLOS. Among the three machine learning models, the RF model achieved the best prediction performance and thus was used to identify the 10 most predictive variables for building the scoring system. The multivariate LR model based on the identified predictors showed good discrimination power with an AUROC of 0.721 in the test dataset, and its coefficients were used as a basis for scoring tool development. On the basis of the developed scoring tool, PD patients were divided into three groups: low risk (≤5), median risk [5–10], and high risk (>10). The observed pLOS proportions in the low-risk, median-risk, and high-risk groups in the test dataset were 11.4%, 29.5%, and 54.7%, respectively.

Conclusions

This study developed a scoring tool to predict pLOS in PD patients. The scoring tool can effectively discriminate patients with different pLOS risks and be easily implemented in clinical practice. The pLOS scoring tool has a great potential to help physicians allocate medical resources optimally and achieve improved clinical outcomes.

Factors Associated With Length of Hospital Stay Following Liver Transplant Surgery

OBJECTIVES

Length of stay is considered an important surrogate for transplant survival rate and resource utilization. Therefore, in the present study, our aim was to determine factors affecting length of hospital stay.

MATERIALS AND METHODS

We retrospectively analyzed records of patients who underwent liver transplant at the Tehran University of Medical Sciences Liver Transplantation Center from March 2014 to March 2016.

RESULTS

For our final analyses, there were 161 adult recipients, including 106 males (65.8%) and 55 females (34.1%). Univariate analyses showed that body mass index, Modelfor End-Stage Liver Disease score, duration of surgery, number of administered packed red blood cells and fibrinogen during surgery, reoperation, retransplant, bacterial infection, pleural effusion, ascites, renal failure that required dialysis, and wound infection were risk factors for length of hospital stay. After multivariate linear regression analysis, only body mass index (β = 0.016; P = .028), Model for End-Stage Liver Disease score (β = 0.017; P = .002), surgical duration (β = 0.002; P = .001), reoperation (β = 0.016; P < .001), presence of pleural effusion (β = 0.212; P = .042), and management of bacterial infection (β = 0.21; P = .03) and psychiatric problems after liver transplant (β = 0.213; P = .025) were independent risk factors for length of hospital stay.

CONCLUSIONS

The present study showed that multiple preoperative, intraoperative, and postoperative variables could have an impact on length of hospitalization. Therefore, methods for assessing these factors could improve patient outcomes and resource savings in liver transplant centers.

Single-Center Experience on Liver Transplantation for Model for End-Stage Liver Disease Score 40 Patients

BACKGROUND

Organ shortage and waiting list mortality have led to changes in the allocation policy in Eurotransplant.

AIM

To identify factors influencing the survival of liver transplanted patients with model for end-stage liver disease (MELD) score of 40.

PATIENTS AND METHODS

Data of listed adult patients who reached a MELD score 40 in the period 12/2006-06/2010 were reviewed. Donor/graft and recipient characteristics, and operative details were analyzed. Statistical analysis encompassed Kaplan-Meier analysis/log-rank test as well as univariate and multivariable regression analyses.

RESULTS

Forty-eight patients achieved a MELD score 40. Thirty patients were transplanted, whereas 18 patients were not. Three-month, 1-year, and 5-year patient and graft survival for transplanted patients was 53, 50, and 47 %, respectively. Three-month and 1-year survival after listing was 11 and 6 % for not transplanted patients, respectively (p < 0.0001). Multivariable analysis revealed pre-operative dialysis (p = 0.0246) and portal vein thrombosis (PVT) (p = 0.0231) to be independent prognostic factors for post-transplant patient survival. A point scoring system was created, which reached statistical significance (p = 0.0007). One-year and 5-year survival for scores 0, 1, and 2 were 72 and 64, 42 and 42 and 0 %, respectively. There was no statistical difference in transplantation costs between patients who survived or died (p = 0.1578).

CONCLUSIONS

At our center, coexistence of pre-operative dialysis and PVT represents a clear contraindication for LT regarding MELD score 40 patients.

Reoperations for Intraabdominal Bleeding Following Deceased Donor Liver Transplantation

Intraabdominal hemorrhage remains one of the most frequent surgical complications after liver transplantation. The aim of the study was to evaluate risk factors for intraabdominal bleeding requiring reoperation and to assess the relevance of the reoperations with respect to short- and long-term outcomes following liver transplantation.

MATERIAL AND METHODS

Data of 603 liver transplantations performed in the Department of General, Transplant and Liver Surgery in the period between January 2011 and September 2014 were analyzed retrospectively. Study end-points comprised: reoperation due to bleeding and death during the first 90 postoperative days and between 90 postoperative day and third post-transplant year.

RESULTS

Reoperations for intraabdominal bleeding were performed after 45 out of 603 (7.5%) transplantations. Low pre-transplant hemoglobin was the only independent predictor of reoperation (p=0.002) with the cut-off of 11.3 g/dl. Postoperative 90-day mortality was significantly higher in patients undergoing reoperation as compared to the remaining patients (15.6% vs 5.6%, p=0.008). Post-transplant survival from 90 days to 3 years was non-significantly lower in patients after reoperation for bleeding (83.3%) as compared to the remaining patients (92.2%, p=0.096). Nevertheless, multivariable analyses did not reveal any significant negative impact of reoperations for bleeding on short-term mortality (p=0.589) and 3-year survival (p=0.079).

CONCLUSIONS

Surgical interventions due to postoperative intraabdominal hemorrhage do not appear to affect short- and long-term outcomes following liver transplantation. Preoperative hemoglobin concentration over 11.3 g/dl is associated with decreased risk of this complication, yet the clinical relevance of this phenomenon is doubtful.

Predictive factors of short term outcome after liver transplantation: A review

Liver transplantation represents a fundamental therapeutic solution to end-stage liver disease. The need for liver allografts has extended the set of criteria for organ acceptability, increasing the risk of adverse outcomes. Little is known about the early postoperative parameters that can be used as valid predictive indices for early graft function, retransplantation or surgical reintervention, secondary complications, long intensive care unit stay or death. In this review, we present state-of-the-art knowledge regarding the early post-transplantation tests and scores that can be applied during the first postoperative week to predict liver allograft function and patient outcome, thereby guiding the therapeutic and surgical decisions of the medical staff. Post-transplant clinical and biochemical assessment of patients through laboratory tests (platelet count, transaminase and bilirubin levels, INR, factor V, lactates, and Insulin Growth Factor 1) and scores (model for end-stage liver disease, acute physiology and chronic health evaluation, sequential organ failure assessment and model of early allograft function) have been reported to have good performance, but they only allow late evaluation of patient status and graft function, requiring days to be quantified. The indocyanine green plasma disappearance rate has long been used as a liver function assessment technique and has produced interesting, although not univocal, results when performed between the 1^th and the 5^th day after transplantation. The liver maximal function capacity test is a promising method of metabolic liver activity assessment, but its use is limited by economic cost and extrahepatic factors. To date, a consensual definition of early allograft dysfunction and the integration and validation of the above-mentioned techniques, through the development of numerically consistent multicentric prospective randomised trials, are necessary. The medical and surgical management of transplanted patients could be greatly improved by using clinically reliable tools to predict early graft function.

Comparison of the ability of the PDD-ICG clearance test, CTP, MELD, and MELD-Na to predict short-term and medium-term mortality in patients with decompensated hepatitis B cirrhosis

OBJECTIVE

Various methods, including the indocyanine green (ICG) clearance test, the Child-Turcotte-Pugh score (CTP), model for end-stage liver disease (MELD), and MELD combined with serum sodium concentration (MELD-Na), have been used widely in liver function evaluation in patients with end-stage liver disease. In this study, we compared the ability of these methods to predict mortality in patients with decompensated hepatitis B cirrhosis.

METHODS

A total of 98 patients with decompensated hepatitis B cirrhosis were included in this study and followed up for 12 months. The ICG-derived measurements (ICG-PDR, ICG-R15, EHBF), CTP, MELD, and MELD-Na were obtained within 2 days after patients' admission and patients' survival at 1, 3, 6, and 12 months was recorded. Receiver operating curve was used to evaluate the ability of these methods to predict mortality in these patients with decompensated hepatitis B cirrhosis.

RESULTS

At 1 month, 3 months, 6 months and 12 months, the cumulative number of deaths and liver transplant recipients was 12 (12.2%), 17 (17.3%), 21 (21.4%) and 25 (25.5%), respectively. The ICG-derived measurements, CTP, MELD, and MELD-Na of nonsurvivors were significantly different compared with that in survivors. All methods yielded viable values in predicting short-term and medium-term prognosis for patients with decompensated hepatitis B cirrhosis, with most area under the curve exceeding 0.8. Moreover, the ICG-derived measurements showed a significant correlation with that of CTP, MELD, and MELD-Na.

CONCLUSION

All four methods, ICG clearance test, CTP, MELD, and MELD-Na, provided reliable prediction of mortality in patients with decompensated hepatitis B cirrhosis for both short-term and medium-term prognosis.