Intraoperative simulation of remnant liver function during anatomic liver resection with indocyanine green clearance (LiMON) measurements

Is an intraoperative liver function assessment possible? Application of the 13C-methacetin-breath-test during major liver resections - a pilot study

BACKGROUND

As prevention of posthepatectomy-liver-failure is crucial, there is need of dynamic assessment of liver function, even intraoperatively. 13C-methacetin-breath-test estimates the organ's microsomal functional capacity. This is its first intraoperative evaluation in major liver surgery.

METHODS

30 patients planed for resection of ≥3 liver segments, between March-November 2019, were prospectively enrolled in this "single-center", pilot study. Using the 13C-methacetin-breath-test, liver function was assessed four times: preoperatively, intraoperatively before and after resection and postoperatively. The resulted maximum-liver-function-capacity (LiMAx)-values and delta-over-baseline (DOB)-curves were compared, further analyzed and correlated to respective liver volumes.

RESULTS

The intraoperative LiMAx-values before resection were mostly lower than the preoperative ones (-11.3% ± 28%). The intraoperative measurements after resection resulted to mostly higher values than the postoperative ones (42.35% ± 46.19%). Pharmacokinetically, an interference between the two intraoperative tests was observed. There was no strong correlation between residual liver volume and function with a percentual residual-LiMAx mostly lower than the percentual residual volume (-17.7% ± 4.1%).

CONCLUSIONS

Intraoperative application of the 13C-methacetin-breath-test during major liver resections seems to deliver lower values than the standard preoperative test. As multiple intraoperative tests interfere significantly to each other, a single intraoperative measurement is suggested. Multicentric standardized measurements could define the "normal" range for intraoperative measurements and control their predictive value.

Post-hepatectomy liver failure: A timeline centered review

BACKGROUND

Post-hepatectomy liver failure (PHLF) is a leading cause of postoperative mortality after liver surgery. Due to its significant impact, it is imperative to understand the risk stratification and preventative strategies for PHLF. The main objective of this review is to highlight the role of these strategies in a timeline centered way around curative resection.

DATA SOURCES

This review includes studies on both humans and animals, where they addressed PHLF. A literature search was conducted across the Cochrane Library, Embase, MEDLINE/PubMed, and Web of Knowledge electronic databases for English language studies published between July 1997 and June 2020. Studies presented in other languages were equally considered. The quality of included publications was assessed using Downs and Black's checklist. The results were presented in qualitative summaries owing to the lack of studies qualifying for quantitative analysis.

RESULTS

This systematic review with 245 studies, provides insight into the current prediction, prevention, diagnosis, and management options for PHLF. This review highlighted that liver volume manipulation is the most frequently studied preventive measure against PHLF in clinical practice, with modest improvement in the treatment strategies over the past decade.

CONCLUSIONS

Remnant liver volume manipulation is the most consistent preventive measure against PHLF.

Indocyanine green clearance test as a predictor of linezolid overexposure in septic patients

OBJECTIVES

Hepatic impairment increases the risk of drug overexposure in septic patients. However, there is a lack of effective indicators to predict overexposure risk. The indocyanine green (ICG) clearance test is a helpful method for dynamically assessing hepatic function and perfusion. This study aimed to investigate whether the ICG test could serve as a potential predictor of linezolid trough concentration (Cmin) and to compare its efficacy with that of conventional liver function markers.

METHODS

A total of 35 consecutive septic patients treated with linezolid were grouped into either linezolid Cmin of ≤7 µg/mL or >7 µg/mL. Correlations between linezolid Cmin and ICG-PDR (plasma disappearance rate), ICG-R15 (retention ratio after 15 min) and other traditional indicators were analysed by Spearman's rank test. A multivariable regression model was employed to discern factors contributing independently to overexposure.

RESULTS

Statistical differences were observed between groups for APACHE II score (P = 0.031), SOFA score (P = 0.018), creatinine clearance (CLCr) (P = 0.003), thrombocytes (P = 0.039), lactate (P = 0.003), ICG-PDR (P < 0.001) and ICG-R15 (P < 0.001). Moreover, linezolid Cmin was correlated with ICG-PDR (ρ = -0.628, P < 0.001), ICG-R15 (ρ = 0.676, P < 0.001) and CLCr (ρ = -0.503, P = 0.002). ICG-PDR was identified as an independent predictor of linezolid overexposure, with an optimal cut-off value of 17.70%/min (93.3% sensitivity, 85.0% specificity; P < 0.001).

CONCLUSIONS

This pilot clinical trial represents the first investigation of potential of the ICG test to predict linezolid overexposure in septic patients.

The value of intraoperative dynamic liver function test ICG in predicting postoperative complications in patients undergoing staged hepatectomy: a pilot study

PURPOSE

To assess the predictive value of intraoperative indocyanine green (ICG) test in patients undergoing staged hepatectomy.

METHODS

We analyzed intraoperative ICG measurements of future liver remnant (FLR), preoperative ICG, volumetry, and hepatobiliary scintigraphy in 15 patients undergoing associated liver partition and portal vein ligation for staged hepatectomy (ALPPS). Main endpoints were the correlation of intraoperative ICG values to postoperative complications (Comprehensive Complication Index (CCI®)) at discharge and 90 days after surgery, and to postoperative liver function.

RESULTS

Median intraoperative R15 (ICG retention rate at 15 min) correlated significantly with CCI® at discharge (p = 0.05) and with CCI® at 90 days (p = 0.0036). Preoperative ICG, volumetry, and scintigraphy did not correlate to postoperative outcome. ROC curve analysis revealed a cutoff value of 11.4 for the intraoperative R15 to predict major complications (Clavien-Dindo ≥ III) with 100% sensitivity and 63% specificity. No patient with R15 ≤ 11 developed major complications.

CONCLUSION

This pilot study suggests that intraoperative ICG clearance determines the functional capacity of the future liver remnant more accurately than preoperative tests. This may further reduce the number of postoperative liver failures, even if it means intraoperative abortion of hepatectomy in individual cases.

Handheld photoacoustic imaging of indocyanine green clearance for real-time quantitative evaluation of liver reserve function

Preoperative assessment of liver function reserve (LFR) is essential for determining the extent of liver resection and predicting the prognosis of patients with liver disease. In this paper, we present a real-time, handheld photoacoustic imaging (PAI) system-based noninvasive approach for rapid LFR assessment. A linear-array ultrasound transducer was sealed in a housing filled with water; its front end was covered with a plastic wrap. This PAI system was first implemented on phantoms to confirm that the photoacoustic (PA) intensity of indocyanine green (ICG) in blood reflects the concentration of ICG in blood. In vivo studies on normal rabbits and rabbits with liver fibrosis were carried out by recording the dynamic PA signal of ICG in their jugular veins. By analyzing the PA intensity-time curve, a clear difference was identified in the pharmacokinetic behavior of ICG between the two groups. In normal rabbits, the mean ICG clearance rate obtained by PAI at 15 min after administration (PAI-R15) was below 21.6%, whereas in rabbits with liver fibrosis, PAI-R15 exceeded 62.0% because of poor liver metabolism. The effectiveness of the proposed method was further validated by the conventional ICG clearance test and pathological examination. Our findings suggest that PAI is a rapid, noninvasive, and convenient method for LFR assessment and has immense potential for assisting clinicians in diagnosing and managing patients with liver disease.

Effect of Hepatic Pathology on Liver Regeneration: The Main Metabolic Mechanisms Causing Impaired Hepatic Regeneration

Liver regeneration has been studied for many decades, and the mechanisms underlying regeneration of normal liver following resection are well described. However, no less relevant is the study of mechanisms that disrupt the process of liver regeneration. First of all, a violation of liver regeneration can occur in the presence of concomitant hepatic pathology, which is a key factor reducing the liver's regenerative potential. Understanding these mechanisms could enable the rational targeting of specific therapies to either reduce the factors inhibiting regeneration or to directly stimulate liver regeneration. This review describes the known mechanisms of normal liver regeneration and factors that reduce its regenerative potential, primarily at the level of hepatocyte metabolism, in the presence of concomitant hepatic pathology. We also briefly discuss promising strategies for stimulating liver regeneration and those concerning methods for assessing the regenerative potential of the liver, especially intraoperatively.

Prediction of Survival After Partial Hepatectomy Using a Physiologically Based Pharmacokinetic Model of Indocyanine Green Liver Function Tests

The evaluation of hepatic function and functional capacity of the liver are essential tasks in hepatology as well as in hepatobiliary surgery. Indocyanine green (ICG) is a widely applied test compound that is used in clinical routine to evaluate hepatic function. Important questions for the functional evaluation with ICG in the context of hepatectomy are how liver disease such as cirrhosis alters ICG elimination, and if postoperative survival can be predicted from preoperative ICG measurements. Within this work a physiologically based pharmacokinetic (PBPK) model of ICG was developed and applied to the prediction of the effects of a liver resection under various degrees of cirrhosis. For the parametrization of the computational model and validation of model predictions a database of ICG pharmacokinetic data was established. The model was applied (i) to study the effect of liver cirrhosis and liver resection on ICG pharmacokinetics; and (ii) to evaluate the model-based prediction of postoperative ICG-R15 (retention ratio 15 min after administration) as a measure for postoperative outcome. Key results are the accurate prediction of changes in ICG pharmacokinetics caused by liver cirrhosis and postoperative changes of ICG-elimination after liver resection, as validated with a wide range of data sets. Based on the PBPK model, individual survival after liver resection could be classified, demonstrating its potential value as a clinical tool.

Hepatectomy-Induced Alterations in Hepatic Perfusion and Function - Toward Multi-Scale Computational Modeling for a Better Prediction of Post-hepatectomy Liver Function

Liver resection causes marked perfusion alterations in the liver remnant both on the organ scale (vascular anatomy) and on the microscale (sinusoidal blood flow on tissue level). These changes in perfusion affect hepatic functions via direct alterations in blood supply and drainage, followed by indirect changes of biomechanical tissue properties and cellular function. Changes in blood flow impose compression, tension and shear forces on the liver tissue. These forces are perceived by mechanosensors on parenchymal and non-parenchymal cells of the liver and regulate cell-cell and cell-matrix interactions as well as cellular signaling and metabolism. These interactions are key players in tissue growth and remodeling, a prerequisite to restore tissue function after PHx. Their dysregulation is associated with metabolic impairment of the liver eventually leading to liver failure, a serious post-hepatectomy complication with high morbidity and mortality. Though certain links are known, the overall functional change after liver surgery is not understood due to complex feedback loops, non-linearities, spatial heterogeneities and different time-scales of events. Computational modeling is a unique approach to gain a better understanding of complex biomedical systems. This approach allows (i) integration of heterogeneous data and knowledge on multiple scales into a consistent view of how perfusion is related to hepatic function; (ii) testing and generating hypotheses based on predictive models, which must be validated experimentally and clinically. In the long term, computational modeling will (iii) support surgical planning by predicting surgery-induced perfusion perturbations and their functional (metabolic) consequences; and thereby (iv) allow minimizing surgical risks for the individual patient. Here, we review the alterations of hepatic perfusion, biomechanical properties and function associated with hepatectomy. Specifically, we provide an overview over the clinical problem, preoperative diagnostics, functional imaging approaches, experimental approaches in animal models, mechanoperception in the liver and impact on cellular metabolism, omics approaches with a focus on transcriptomics, data integration and uncertainty analysis, and computational modeling on multiple scales. Finally, we provide a perspective on how multi-scale computational models, which couple perfusion changes to hepatic function, could become part of clinical workflows to predict and optimize patient outcome after complex liver surgery.

Current State of Multidisciplinary Treatment in Cholangiocarcinoma

BACKGROUND

Cholangiocarcinoma (CCA) is a highly aggressive malignancy, and its incidence seems to be increasing over the last years. Given the high rate of irresectability at the time of initial diagnosis, new treatment approaches are important to achieve better patient outcomes. Our review provides an overview of current multimodal therapy options across different specialties of gastroenterology/oncology, surgery, and interventional radiology.

SUMMARY

CCA is subdivided into clinically and molecularly distinct phenotypes. Surgical treatment currently is the only potentially curative therapy, but unfortunately, the majority of all patients are not eligible for resection at the time of initial diagnosis due to anatomic location, inadequate hepatic reserve, metastatic disease, or limiting comorbidities. However, multimodal treatment options are available to prolong survival, relieve symptoms, and maintain life quality.

KEY MESSAGES

The treatment of CCA is complex and requires close interdisciplinary collaboration and individualized treatment planning to ensure optimal patient care at specialized centers. Molecular profiling of patients and inclusion into clinical trials is highly recommended.

Predicting Post-Hepatectomy Liver Failure Using Intra-Operative Measurement of Indocyanine Green Clearance in Anatomical Hepatectomy

BACKGROUND

Prediction of post-hepatectomy liver failure (PHLF) based on remnant liver function reserve is important for successful hepatectomy. The aim of this study was to investigate whether intraoperative indocyanine green (ICG) clearance in a future remnant liver was a predictor of PHLF.

METHODS

This prospective study enrolled 31 consecutive patients who underwent anatomical hepatectomy between June 2016 and August 2019. Intraoperative ICG plasma disappearance rate (ICG-PDR) and ICG retention rate at 15 min (ICG-R15) were measured after clamping the selective hepatic inflow to the liver to be resected. The discriminative performance of the ICG-associated variables for the prediction of PHLF grade B/C was evaluated by receiver operator curve (ROC) analysis.

RESULTS

Of the operations performed, 87.1% were major hepatectomy. PHLF Grade B/C was observed in eight patients (25.8%) with no mortality. The concordance indices of intraoperative ICG-PDR and ICG-PDR for predicting PHLF were 0.834 (95% CI, 0.69-0.98) and 0.834 (95% CI, 0.69-0.98), respectively. A subgroup analysis of patients with preoperative biliary drainage (BD) (n = 17) showed that the concordance indices of intraoperative ICG-PDR increased to 0.923 (95% CI, 0.79-1.00).

CONCLUSIONS

Intraoperative ICG clearance in the remnant liver was a promising predictor for PHLF in patients undergoing anatomical hepatectomy, especially in patients with BD.

Adenosine A2a Receptor Stimulation Attenuates Ischemia-Reperfusion Injury and Improves Survival in A Porcine Model of DCD Liver Transplantation

Orthotopic liver transplantation (OLT) using allografts from donation after circulatory death (DCD) is potentially associated with compromised clinical outcomes due to ischemia-reperfusion injury (IRI)-induced organ damage and graft-related complications. The aim of this study was to provide in vivo data on the effects of adenosine A2a receptor stimulation in a clinically relevant large animal model of DCD liver transplantation. Cardiac arrest was induced in German Landrace pigs (n = 10; 20-25 kg). After 30 min of warm ischemia, the donor liver was retrieved following a cold flush with 3 L of histidine-tryptophan-ketoglutarate-HTK solution. Animals of the treatment group (n = 5/group) received a standard dose of the selective adenosine receptor agonist CGS 21680 added to the cold flush. All grafts were stored for 4.5 h at 4 °C in HTK-solution before OLT. Hepatocellular injury, apoptosis, protein kinase A-PKA activity, graft microcirculation, liver function, and animal survival were assessed. Compared to untreated livers, adenosine A2a receptor stimulation resulted in improved tissue microcirculation (103% ± 5% vs. 38% ± 4% compared to baseline; p < 0.05), accelerated functional recovery of the graft (indocyanine green-plasma disappearance rate (ICG-PDR) of 75% ± 18% vs. 40% ± 30% after 3 h), increased PKA activity ratio (56% ± 3% vs. 32% ± 3%; p < 0.001 after 1 h), and consequently reduced tissue necrosis and apoptosis. The potent protective effects were clinically manifested in significantly improved survival in the treatment group after 72 h (100% vs. 40%; p = 0.04). The ex vivo administration of adenosine A2a receptor agonist during the back-table flush mitigates IRI-mediated tissue damage and improves functional graft recovery and survival in a large animal model of DCD liver transplantation.

Hepatic function assessment to predict post-hepatectomy liver failure: what can we trust? A systematic review

Post hepatectomy liver failure (PHLF) could occur even though an adequate liver volume is preserved. Liver function is not strictly related to the volume and the necessity to pre-operatively predict the future liver remnant (FLR) function is emerging, together with the wide spreading of techniques, aiming to optimize the FLR. The aim of this study was to systematically review all the available tests, to pre-operatively assess the liver function and to estimate the risk of PHLF. A systematic literature research of Medline, Embase, Scopus was performed in accordance to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, to identify all the studies available for pre-operative liver function tests to assess the risk of PHLF and/or complications. From the 1122 references retrieved, 79 were included in the review. Dynamic functional tests, such as indocyanine green test (ICG), could evaluate only global liver function, with no definition of functional capacity of the remnant. Magnetic resonance imaging (MRI) with liver-specific contrast agents enables both liver function and volume evaluation; the absence of ionizing radiation showed a better patient's compliance. Nuclear imaging studies as hepatobiliary scintigraphy (HBS) present the unique ability to allow a precise evaluation of the segmental liver function of the remnant liver. Liver volume could overestimate liver function. Several liver function tests are available to evaluate the risk of PHLF in the pre-operative setting. However, no single test alone could accurately predict PHLF. Pre-operative combination between a dynamic quantitative test, such as ICG, with MRI or HBS, should enable a more complete functional evaluation. Functional tests to predict PHLF should be chosen according to patient's characteristics, disease, and center experience.

Predictive Value of Intraoperative Indocyanine Green Clearance Measurement on Postoperative Liver Function After Anatomic Major Liver Resection

BACKGROUND

The aim of this study was to evaluate the predictive value of measuring indocyanine green (ICG) clearance during intraoperative partial occlusion of liver lobes to be resected on postoperative liver function following major anatomic liver resection.

METHODS

We prospectively included 46 patients, and 35 patients ultimately underwent anatomic major liver resection. ICG clearance was measured preoperatively and intraoperatively. Intraoperative ICG clearance was measured immediately after selective occlusion of hepatic arterial, portal, and hepatic venous blood flow to the liver lobes to be resected. The albumin-bilirubin (ALBI) grade, albumin-indocyanine green evaluation (ALICE) grade, platelet count, remnant liver volume per kilogram of weight (RLV/kg), and future liver remnant plasma clearance rate of ICG (ICGK-FLR) were measured preoperatively.

RESULTS

An intraoperative ICG retention at 15 min (I-R15) greater than 13.8% indicates transient posthepatectomy liver failure (PHLF) and Clavien-Dindo > grade I complications. Receiver operating characteristic (ROC) curve analysis revealed that the area under the curve (AUC) for predicting PHLF and Clavien-Dindo > grade I complications was 0.797 and 0.734, respectively (p = 0.001 and 0.014). Furthermore, an I-R15 greater than 22.7% indicates mid-term PHLF, and the AUC was 0.911 (p < 0.0001). The I-R15 is a better predictor of PHLF than the ALBI grade, ALICE grade, platelet count, RLV/kg, and ICGK-FLR.

CONCLUSIONS

Intraoperative ICG clearance measurements during partial occlusion of blood flow accurately predict postoperative liver function and could be new criteria for determining the feasibility and safety of anatomic major liver resection.

Dealing with insufficient liver remnant: Associating liver partition and portal vein ligation for staged hepatectomy

Liver resection for colorectal liver metastases has emerged to highly successful treatment in the last decades. Key to this success is complete hepatic tumor removal and systemic disease control by chemotherapy. Associating liver partition and portal vein ligation for staged hepatectomy is the most recent two-stage resection strategy for patients with very small future liver remnant making complete tumor removal possible within 1 to 2 weeks. Oncological outcome data are being collected at the moment and first results from small series reveal promising results.

Non-invasive Evaluation of NAFLD with Indocyanine Green Clearance Test: a Preliminary Study in Morbidly Obese Patients Undergoing Bariatric Surgery

BACKGROUND

Overweight and obesity dramatically increased in the last years. Hepatic complication of obesity, integrated in the term of non-alcoholic fatty liver disease (NAFLD), is a spectrum of abnormality ranging from steatosis to non-alcoholic steatohepatitis (NASH), potentially leading to cirrhosis. Liver biopsy remains the gold standard to evaluate the stage of NAFLD; however, the procedure is invasive. The indocyanine green (ICG) clearance test is performed since years to assess hepatic function before partial hepatectomy, or after liver transplantation. This study was designed to detect liver complications with the ICG clearance test in a population of obese patients scheduled for bariatric surgery.

METHODS

In a prospective cohort study, morbidly obese individuals receiving bariatric surgery with scheduled hepatic biopsies were investigated. Liver function was determined by the ICG test preoperatively, and blood samples were collected. Liver biopsy specimens were obtained for each patient and classified according to the NAFLD activity score (NAS) by a single pathologist that was blinded to the results of the ICG test.

RESULTS

Twenty-six patients were included (7 male and 19 female). The mean age of participants was 45.8 years; the mean body mass index was 41.4 kg/m². According to the NAS, 6 (23.1%) patients revealed manifest NASH, and 5 patients were considered borderline (19.2%). A closed correlation was observed between the ICG clearance test and hepatic steatosis (r = 0.43, p = 0.03), NAS (r = 0.44, p = 0.025), and fibrosis (r = 0.49, p = 0.01).

CONCLUSIONS

In obese patients, non-invasive evaluation of liver function with the indocyanine green clearance test correlated with histological features of NAFLD. This may detect non-invasively hepatopathy in obese population and could motive biopsy.

Clinical and prognostic associations of liver volume determined by computed tomography in acute liver failure

BACKGROUND

Liver volume (LV) can be non-invasively determined from the analysis of computed tomography (CT) images, and in patients with acute liver injury (ALI) or failure (ALF), it can reflect the balance of structural collapse with hepatic regeneration. We examined its relation to cause of liver injury, measures of liver function and histopathological findings, and utility in prediction of complications and mortality.

METHODS

Two hundred and seventy-three patients with ALF/ALI admitted to a specialist intensive care unit were studied. One hundred and ninety-nine patients (73%) had non-acetaminophen (NA) aetiologies and 74 (27%) had acetaminophen-induced disease. LV and proportion of predicted LV (PLV%) were determined from admission CT imaging.

RESULTS

LV and PLV% showed marked variation when aetiologic groups were compared (P < .0001), including loss in cases with indeterminate cause (LV 939 cm³ [IQR 680-1259], PLV% 56% [42-84]) and increase in Budd-Chiari syndrome (1891 cm³ [1601-2094], 121% [111-131]). Progression to high-grade encephalopathy was more common with smaller LV and PLV. A < 1000 cm³ threshold identified NA patients who later developed it with 93% (95%CI 83-98) specificity and odds ratio 10.6 (3.3-34.5) at median 5 days prior to onset, and risk of death in those with NA-drug-induced (DILI) or indeterminate disease with 91% (71-99) specificity and 63% (50-75) sensitivity.

CONCLUSION

In patients with ALF/ALI, LV shows marked variation by the cause of disease, and in prognostic importance. In indeterminate and DILI cases, loss of volume to <1000 cm³ may indicate irreversible liver injury and regenerative failure and serve as an early clinical predictor for the development of high-grade encephalopathy and death.

Development of novel biological resection criteria for safe and oncologically satisfying resection of hepatocellular carcinoma

OBJECTIVE

To develop criteria for safe and oncologically satisfying liver resection in case of early hepatocellular carcinoma with a 5-year overall survival (OS) similar to liver transplantation.

SUMMARY BACKGROUND DATA

Liver resection (LR) and liver transplantation (LT) are potentially curative treatment options for hepatocellular carcinoma. Generally, LT achieves better OS. Due to organ shortage, however not all patients can receive a LT.

METHODS

To decide which patients to resect and which to transplant we have developed biological resection criteria (BRC) as a compound out of mGPS (modified Glascow Prognostic Scale) and the Kings-Score (for HCV cirrhosis). These are based on routine clinical values that reflect both liver function and tumor biology/immunology.

RESULTS

276 patients were analyzed. Patients undergoing LR within BRC (_inBRC) had a significantly better overall (73.6% vs. 35.4%, (p < 0.001)) and disease-free survival (54.7% vs. 17.2%, (p < 0.001)) as compared to patients outside the BRC (_outBRC). The predictive value of BRC was independent of tumor burden. In a subgroup analysis _outBRC patients had significantly worse outcome after major resection. In LT patients BRC had no predictive value.

CONCLUSIONS

BRC may be a valuable tool to predict survival after LR for HCC. Patients resected _inBRC may achieve comparable survival as LT. LR in _outBRC patients are unlikely to be curative. All _outBRC patients should be monitored closely for salvage LT.

Laparoscopic treatment of a patent ductus venosus and the use of indocyanine green to monitor perioperative hepatic function

Patent ductus venosus (PDV) is an uncommon but important congenital portocaval shunt that can lead to numerous complications if untreated. This case describes the successful management of a 17-year-old male with symptomatic PDV. Doppler ultrasonography and contrast-enhanced computed tomography (CT) confirmed a large communication between the left portal vein and the inferior vena cava. Angiography demonstrated a large and high flow PDV which precluded its therapeutic embolization. Based on these findings, laparoscopic closure of the PDV was elected and successfully performed. Perioperative indocyanine green (ICG) clearance was performed and marked improvement was observed following the occlusion of the PDV. The patient showed immediate resolution of symptoms post-operatively and remains asymptomatic 2 years after his surgery. Laparoscopic approach to the management of PDV is feasible. ICG clearance, for the first time, was demonstrated in this setting to be a useful and rapid bedside test for the real-time assessment of liver function.

ICG Clearance Test and 99mTc-GSA SPECT/CT Fusion Images

Preoperative estimation of future remnant liver function is critical for major hepatic surgery to avoid postoperative morbidity and mortality. Among several liver function tests, the indocyanine green (ICG) clearance test is still the most popular dynamic method. The usefulness of ICG clearance test parameters, such as ICGR15, KICG, or PDRICG, has been reported by many investigators. The transcutaneous non-invasive pulse dye densitometry system has made the ICG clearance test more convenient and attractive, even in Western countries. The concept of future remnant KICG (rem KICG), which combines the functional aspect and the volumetric factor of the future remnant liver, seems ideal for determining the maximum extent of major hepatic resection that will not cause postoperative liver failure. For damaged livers with functional heterogeneity among the hepatic segments, fusion images combining technetium-99m-diethylenetriaminepentaacetic acid-galactosyl human serum albumin single photon emission computed tomography (99mTc-GSA SPECT) and X-ray CT are helpful to precisely estimate the functional reserve of the future remnant liver. Another technique for image-based liver function estimation, gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid(Gd-EOB)-enhanced magnetic resonance imaging, may be an ideal candidate for the preoperative determination of future remnant liver function. Using these methods effectively, morbidity and mortality after major hepatic resection could be reduced.

Surgical resection of localized hepatocellular carcinoma: patient selection and special consideration

Localized hepatocellular carcinoma (HCC) refers to a solitary or few tumors located within either the left or right hemiliver without evidence of bilobar or extrahepatic spread. This term encompasses a heterogeneous morphology with no regard to stage of prognosis of the disease. Surgical resection remains the mainstay of curative treatment for the localized HCC. Various biochemical and radiological tests constitute an indispensible part of preoperative assessment. Emergence of laparoscopic hepatectomy has brought liver resection into a new era. Improved understanding of the pathophysiology of HCC allows more aggressive surgical resection without compromising outcomes. New insights into the management of special situations, such as ruptured HCC, pyogenic transformation of HCC, and HCC with portal vein tumor thrombus, rekindle the hopes of curative resection in these terminal events. Amalgamating salvage liver transplantation into the surgical management of resectable HCC has revolutionized the treatment paradigm of this deadly disease.

Quantification of hepatic functional capacity: a call for standardization

Reliable assessments of liver function are becoming increasingly important as more patients with surgically amenable liver disease are considered for treatment. Static markers of liver function are not sufficient to provide accurate assessments of hepatic function in order to risk stratify patients undergoing hepatic resection. Metabolic tests are dynamic indicators of liver function, but can be unreliable under certain conditions and thus difficult to make comparisons. Clearance tests avoid some of the pitfalls encountered during metabolic testing, but depend on hepatic blood flow and say little about hepatocyte function. Testing that combines imaging with measures of hepatocyte uptake may offer the most utility when planning surgical resections.

Evaluation of liver function and electroacupuncture efficacy of animals with alcoholic liver injury by the novel imaging methods

Imaging methods to evaluate hepatic microcirculation (HM) and liver function (LF) by directly monitoring overall liver tissue remain lacking. This study establish imaging methods for LF that combines Laser speckle perfusion imaging (LSPI) and in vivo optical imaging (IVOI) technologies to investigate changes of hepatic microcirculation and reserve function in the animals gavaged with 50% ethanol (15 ml/kg·bw) for a model of acute alcoholic liver injury (ALI), and for evaluation of electroacupuncture (EA) effect. The liver blood perfusion and indocyanine green (ICG) distribution were observe by LSPI and IVOI separately. After EA, the livers were collected to measure the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), thromboxane A (TXA₂), prostacyclin (PGI₂) and endothelin (ET). The acquisitions of newly established LSPI of liver and ICG in vivo fluorescence imaging (ICG-IVFI), combining the results of other indexes showed: hepatic microcirculation perfusion (HMP) significantly reduced, ICG metabolism reduced, and ALT/AST increased in animal model with acute ALI. EA can reverse these changes. The use of LSPI of liver and ICG-IVFI, which was novel imaging methods for LF established in this study, could display the LF characteristics of ALI and the EA efficacy.

Indocyanine green kinetics to assess liver function: Ready for a clinical dynamic assessment in major liver surgery?

Indocyanine green (ICG) kinetics (PDR/R15) used to quantitatively assess hepatic function in the perioperative period of major resective surgery and liver transplantation have been the object of an extensive, updated and critical review. New, non invasive bedside monitors (pulse dye densitometry technology) make this opportunity widely available in clinical practice. After having reviewed basic concepts of hepatic clearance, we analysed the most common indications ICG kinetic parameters have nowadays in clinical practice, focusing in particular on the diagnostic and prognostic role of PDR and R15 in the perioperative period of major liver surgery and liver transplantation. As recently pointed out, even if of extreme interest, ICG clearance parameters have still some limitations, to be considered when using these tests.

Prediction of Mortality After ALPPS Stage-1: An Analysis of 320 Patients From the International ALPPS Registry. Ann Surg. 2015;262:780-5; discussion 785-6. [PMID: 26583666 DOI: 10.1097/sla.0000000000001450]

OBJECTIVES

The aim of this study was to identify predictors of 90-day mortality after Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy (ALPPS), available after stage-1, either to omit or delay stage-2.

BACKGROUND DATA

ALPPS is a two-stage hepatectomy for patients with extensive liver tumors with predicted small liver remnants, which has been criticized for its high mortality rate. Risk factors for mortality are unknown.

METHODS

Patients in the International Registry undergoing ALPPS from April 2011 to July 2014 were analyzed. Primary outcome was 90-day mortality. Liver function after stage-1 was assessed using the criteria of the International Study Group for Liver Surgery (ISGLS) after stage-1 among others. A multivariable model was used to identify independent predictors of 90-day mortality.

RESULTS

Three hundred twenty patients registered by 55 centers worldwide were evaluated. Overall 90-day mortality was 8.8% (28/320). The predominant cause for 90-day mortality was postoperative liver failure in 75% of patients. Fourteen percent of patients developed liver failure according to ISGLS criteria already after stage-1 ALPPS. Those and patients with a model of end-stage liver disease (MELD) score more than 10 before stage-2 were at significantly higher risk for 90-day mortality after stage-2 with an odds ratio (OR) 3.9 [confidence interval (CI) 1.4-10.9, P = 0.01] and OR 4.9 (CI 1.9-12.7, P = 0.006), respectively. Other factors, such as size of future liver remnant (FLR) before stage-2 and time between stages, were not predictive.

CONCLUSIONS

This analysis of the largest cohort of ALPPS patients so far identifies those patients in whom stage-2 ALPPS surgery should be delayed or even denied. These findings may help to make ALPPS safer.

Portable device for the analysis of liver function: a boon to liver surgery and critical care

Liver biology, liver disease and its management present a myriad of challenges to clinicians. Difficulties arise in determining liver functional capacity, which must be effectively measured in a quantitative reproducible manner. Measurement of indocyanine green (ICG) clearance, an exceptional tool that has been used for decades to assess liver function, has traditionally been cumbersome to perform. New technology now allows for rapid and noninvasive determination of ICG clearance making it clinically accessible. This adds ICG clearance measurement to the armamentarium of physiologic monitors that could be routinely used in the evaluation of patients undergoing liver surgery or in the intensive care setting.