Major hepatic resection: from volumetry to liver scintigraphy

Vascular damage and excessive proliferation compromise liver function after extended hepatectomy in mice

BACKGROUND AND AIMS

Surgical resection remains the gold standard for liver tumor treatment, yet the emergence of postoperative liver failure, known as the small-for-size syndrome (SFSS), poses a significant challenge. The activation of hypoxia sensors in an SFSS liver remnant initiated early angiogenesis, improving the vascular architecture, safeguarding against liver failure, and reducing mortality. The study aimed to elucidate vascular remodeling mechanisms in SFSS and their impact on hepatocyte function and subsequent liver failure.

APPROACH AND RESULTS

Mice underwent extended partial hepatectomy to induce SFSS, with a subset exposed to hypoxia immediately after surgery. Hypoxia bolstered posthepatectomy survival rates. The early proliferation of liver sinusoidal cells, coupled with recruitment of putative endothelial progenitor cells, increased vascular density, improved lobular perfusion, and limited hemorrhagic events in the regenerating liver under hypoxia. Administration of granulocyte colony-stimulating factor in hepatectomized mice mimicked the effects of hypoxia on vascular remodeling and endothelial progenitor cell recruitment but failed to rescue survival. Compared to normoxia, hypoxia favored hepatocyte function over proliferation, promoting functional preservation in the regenerating remnant. Injection of Adeno-associated virus serotype 8-thyroxine-binding globulin-hepatocyte nuclear factor 4 alpha virus for hepatocyte-specific overexpression of hepatocyte nuclear factor 4 alpha, the master regulator of hepatocyte function, enforced functionality in proliferating hepatocytes but did not rescue survival. The combination of hepatocyte nuclear factor 4 alpha overexpression and granulocyte colony-stimulating factor treatment rescued survival after SFSS-setting hepatectomy.

CONCLUSIONS

In summary, SFSS arises from an imbalance and desynchronized interplay between functional regeneration and vascular restructuring. To improve survival following SFSS hepatectomy, it is essential to adopt a 2-pronged strategy aimed at preserving the function of proliferating parenchymal cells and simultaneously attenuating vascular damage.

Joint EANM/SNMMI/IHPBA procedure guideline for [99mTc]Tc-mebrofenin hepatobiliary scintigraphy SPECT/CT in the quantitative assessment of the future liver remnant function

PURPOSE

The aim of this joint EANM/SNMMI/IHPBA procedure guideline is to provide general information and specific recommendations and considerations on the use of [99mTc]Tc-mebrofenin hepatobiliary scintigraphy (HBS) in the quantitative assessment and risk analysis before surgical intervention, selective internal radiation therapy (SIRT) or before and after liver regenerative procedures. Although the gold standard to estimate future liver remnant (FLR) function remains volumetry, the increasing interest in HBS and the continuous request for implementation in major liver centers worldwide, demands standardization.

METHODS

This guideline concentrates on the endorsement of a standardized protocol for HBS elaborates on the clinical indications and implications, considerations, clinical appliance, cut-off values, interactions, acquisition, post-processing analysis and interpretation. Referral to the practical guidelines for additional post-processing manual instructions is provided.

CONCLUSION

The increasing interest of major liver centers worldwide in HBS requires guidance for implementation. Standardization facilitates applicability of HBS and promotes global implementation. Inclusion of HBS in standard care is not meant as substitute for volumetry, but rather to complement risk evaluation by identifying suspected and unsuspected high-risk patients prone to develop post-hepatectomy liver failure (PHLF) and post-SIRT liver failure.

Post-hepatectomy liver failure prediction and prevention: Development of a nomogram containing postoperative anticoagulants as a risk factor

INTRODUCTION AND OBJECTIVES

Posthepatectomy liver failure (PHLF) is a serious complication after hepatectomy, and its effective methods for preoperative prediction are lacking. Here, we aim to identify predictive factors and build a nomogram to evaluate patients' risk of developing PHLF.

PATIENTS AND METHODS

A retrospective review of a training cohort, including 199 patients who underwent hepatectomy at the Shanghai Eastern Hepatobiliary Surgery Hospital, was conducted. Independent risk variables for PHLF were identified using multivariate analysis of perioperative variables, and a nomogram was used to build a predictive model. To test the predictive power, a prospective study in which a validation cohort of 71 patients was evaluated using the nomogram. The prognostic value of this nomogram was evaluated by the C-index.

RESULTS

Independent risk variables for PHLF were identified from perioperative variables. In multivariate analysis of the training cohort, tumor number, Pringle maneuver, blood loss, preoperative platelet count, postoperative ascites and use of anticoagulant medications were determined to be key risk factors for the development of PHLF, and they were selected for inclusion in our nomogram. The nomogram showed a 0.911 C-index for the training cohort. In the validation cohort, the nomogram also showed good prognostic value for predicting PHLF. The validation cohort was used with similarly successful results to evaluate risk in two previously published study models with calculated C-indexes of 0.718 and 0.711.

CONCLUSION

Our study establishes for the first time a novel nomogram that can be used to identify patients at risk of developing PHLF.

Variations between the anatomical and functional distribution, based on 99m technetium -mebrofinate SPECT-CT scan, in patients at risk of post hepatectomy liver failure

BACKGROUND

The aim of the current study is to investigate the variations of anatomical (LV_Rem%) and functional remnant volumes (fLV_Rem%) and the dynamic uptake of Technetium-Mebrofinate (FRLF) measured from 99^m Technetium-Mebrofinate SPECT-CT scan (TMSCT) in patients at high risk of post-hepatectomy liver failure (PHLF).

METHODS

Variations in the measures of LV_Rem% and fLV_Rem% were assessed. The predictive accuracies of LV_Rem%, fLV_Rem% and FRLF with respect to PHLF were reported.

RESULTS

From the N = 92 scans performed, LV_Rem% and fLV_Rem% returned identical results in 15% of cases, and ±10 percentage points in 79% of cases. Some patients had larger discrepancies, with difference of >10 percentage points in 21% of cases. The difference was significant in those with primary liver cancers (-4.4 ± 9.2, p = 0.002). For the N = 29 patients that underwent surgery as planned on TMSCT, FRLF was a strong predictor of PHLF, with an AUROC of 0.83 (p = 0.005).

CONCLUSION

TMSCT is emerging as a useful modality in pre-operative assessment of patients undergoing major liver resection. For those with primary liver cancer, there is a significant variation in the anatomical and functional distributions that needs considered in surgical planning. Reduced FRLF, measured as the dynamic uptake in the future liver remnant, is a strong predictor of PHLF.

Determination of the segmental hepatic clearance rate of 99mTc-mebrofenin and its application in the functional assessment of future liver remnant after liver resection

^99mTc-mebrofenin hepatobiliary scintigraphy with SPECT/CT (HBS-M) has become an important quantitative method to evaluate global liver function and future liver remnant (FLR) function in patients who are candidates for resective liver surgery. The purpose of this work was to describe the method in the prediction of post-surgical liver failure. The overall liver function and that of the FLR are obtained by analysis of the initial dynamic phase of the scan. Liver volume to be preserved is expressed as a percentage of the total liver volume measured in both CT sections. HBS-M is able to accurately gauge regional liver function abnormalities that could be represented as normal liver tissue parenchyma in the CT study. This technique can provide very valuable prognostic information for the estimation of the postoperative risk of liver failure in all patients who are candidates for resective liver surgery.

Development and Validation of a Nomogram Based on Perioperative Factors to Predict Post-hepatectomy Liver Failure

BACKGROUND AND AIMS

Post-hepatectomy liver failure (PHLF) is a severe complication and main cause of death in patients undergoing hepatectomy. The aim of this study was to build a predictive model of PHLF in patients undergoing hepatectomy.

METHODS

We retrospectively analyzed patients undergoing hepatectomy at Zhongshan Hospital, Fudan University from July 2015 to June 2018, and randomly divided them into development and internal validation cohorts. External validation was performed in an independent cohort. Least absolute shrinkage and selection operator (commonly referred to as LASSO) logistic regression was applied to identify predictors of PHLF, and multivariate binary logistic regression analysis was performed to establish the predictive model, which was visualized with a nomogram.

RESULTS

A total of 492 eligible patients were analyzed. LASSO and multivariate analysis identified three preoperative variables, total bilirubin (p=0.001), international normalized ratio (p<0.001) and platelet count (p=0.004), and two intraoperative variables, extent of resection (p=0.002) and blood loss (p=0.004), as independent predictors of PHLF. The area under receiver operating characteristic curve (referred to as AUROC) of the predictive model was 0.838 and outperformed the model for end-stage liver disease score, albumin-bilirubin score and platelet-albumin-bilirubin score (AUROCs: 0.723, 0.695 and 0.663, respectively; p<0.001 for all). The optimal cut-off value of the predictive model was 14.7. External validation showed the model could predict PHLF accurately and distinguish high-risk patients.

CONCLUSIONS

PHLF can be accurately predicted by this model in patients undergoing hepatectomy, which may significantly contribute to the postoperative care of these patients.

An ordinal model to predict the risk of symptomatic liver failure in patients with cirrhosis undergoing hepatectomy

BACKGROUND & AIMS

Selection criteria for hepatectomy in patients with cirrhosis are controversial. In this study we aimed to build prognostic models of symptomatic post-hepatectomy liver failure (PHLF) in patients with cirrhosis.

METHODS

This was a cohort study of patients with histologically proven cirrhosis undergoing hepatectomy in 6 French tertiary care hepato-biliary-pancreatic centres. The primary endpoint was symptomatic (grade B or C) PHLF, according to the International Study Group of Liver Surgery's definition. Twenty-six preoperative and 5 intraoperative variables were considered. An ordered ordinal logistic regression model with proportional odds ratio was used with 3 classes: O/A (No PHLF or grade A PHLF), B (grade B PHLF) and C (grade C PHLF).

RESULTS

Of the 343 patients included, the main indication was hepatocellular carcinoma (88%). Laparoscopic liver resection was performed in 112 patients. Three-month mortality was 5.25%. The observed grades of PHLF were: 0/A: 61%, B: 28%, C: 11%. Based on the results of univariate analyses, 3 preoperative variables (platelet count, liver remnant volume ratio and intent-to-treat laparoscopy) were retained in a preoperative model and 2 intraoperative variables (per protocol laparoscopy and intraoperative blood loss) were added to the latter in a postoperative model. The preoperative model estimated the probabilities of PHLF grades with acceptable discrimination (area under the receiver-operating characteristic curve [AUC] 0.73, B/C vs. 0/A; AUC 0.75, C vs. 0/A/B) and the performance of the postoperative model was even better (AUC 0.77, B/C vs. 0/A; AUC 0.81, C vs. 0/A/B; p <0.001).

CONCLUSIONS

By accurately predicting the risk of symptomatic PHLF in patients with cirrhosis, the preoperative model should be useful at the selection stage. Prediction can be adjusted at the end of surgery by also considering blood loss and conversion to laparotomy in a postoperative model, which might influence postoperative management.

LAY SUMMARY

In patients with liver cirrhosis, the risk of a hepatectomy is difficult to appreciate. We propose a statistical tool to estimate this risk, preoperatively and immediately after surgery, using readily available parameters and on online calculator. This model could help to improve the selection of patients with the best risk-benefit profiles for hepatectomy.

Associating liver partition and portal vein ligation for staged hepatectomy: establishment of an animal model with insufficient liver remnant

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) allows extended hepatectomy in patients with an extremely small future liver remnant (FLR). Current rodent models of ALPPS do not include resection resulting in insufficient-for-survival FLR, or they do incorporate liver mass reduction prior to ALPPS. Differences in FLR volume and surgical procedures could bias our understanding of physiological and hemodynamic mechanisms. We aimed to establish a rat ALPPS model with minimal FLR without prior parenchymal resection. In rodents, the left median lobe (LML) represents 10% of total liver. Partial hepatectomy (PHx) sparing LML and pericaval parenchyma represents our reference 87% resection. The first step in the procedure is either portal vein ligation (PVL) corresponding to ligation of all but the LML portal branches, or PVL with transection between the left and right median lobe segments (PVLT), and is defined as ALPPS stage-1. Second, ligated lobes were removed: PVL-PHx represents a conventional 2-stage hepatectomy, while PVLT followed by PHx is a strict reproduction of human ALPPS. In Group A, liver hypertrophy was analyzed after PVL (n = 38), PVLT (n = 47), T (n = 10), and sham (n = 10); In group B, mortality and FLR hypertrophy was assessed after PHx (n = 42), Sham-PHx (n = 6), PVL-PHx (n = 37), and PVLT-PHx (n = 45). In group A, PVLT induced rapid FLR hypertrophy compared to PVL (p < 0,05). Hepatocyte proliferation was higher in PVLT remnants (p < 0,05). In group B, PHx had a 5-day mortality rate of 84%. Sham operation prior to PHx did not improve survival (p = 0.23). In both groups, major fatalities occurred within 48 h after resection. PVL or PVLT prior to PHx reduced mortality to 33.3% (p = 0,007) or 25% (p = 0.0002) respectively, with no difference between the 2 two-stage procedures (p = 0.6). 7-day FLR hypertrophy was higher after the PVLT-PHx compared to PVL-PHx and PHx (p = 0.024). Our model reproduces human ALPPS with FLR that is insufficient for survival without liver resection prior to the stage-1 procedure. It offers an appropriate model for analyzing the mechanisms driving survival rescue and increased hypertrophy.