Assessment of effective hepatic blood flow in critically ill patients by noninvasive pulse dye-densitometry

Association between effective hepatic blood flow and the severity and prognosis of hepatitis B virus-related acute on chronic liver failure

BACKGROUND

Hepatic inflammation resulted in hepatocyte necrosis and microcirculatory dysfunction in acute on chronic liver failure (ACLF) with cirrhosis or not. The influence of effective hepatic blood flow (EHBF) on the severity of liver failure has not been fully elucidated.

AIM

The aim of this study was to assess the correlation between the EHBF and the severity and the prediction of 90-day mortality rate of hepatitis B virus-related ACLF (HBV-ACLF).

METHODS

In this retrospective study, patients hospitalized for HBV-ACLF or decompensated cirrhosis and who underwent an indocyanine green (ICG) clearance test between June 2016 and July 2018 were enrolled. EHBF was measured by the ICG clearance test and patients were categorized into the ACLF without cirrhosis (HBV-ACLF-no-Cir), ACLF with cirrhosis (HBV-ACLF-Cir) and decompensated cirrhosis (HBV-De-Cir).

RESULTS

A total of 522 patients (HBV-ACLF-no-Cir: 84, HBV-ACLF-Cir: 111 and HBV-De-Cir: 327) were enrolled. The mean EHBF in the HBV-De-Cir was significantly higher than that in the HBV-ACLF-no-Cir and HBV-ACLF-Cir (0.36 vs. 0.21 vs. 0.20 L/min, P < 0.001). EHBF was significantly correlated with the total bilirubin, prothrombin activity and model for end-stage liver disease (MELD) in the HBV-ACLF-no-Cir. The predicted 90-day mortality rate using the MELD, EHBF, ICG-retention rate at 15 min (R15%) and EHBF-R15% scores were similar. The sensitivity and specificity of the EHBF varied between 68.5-80.2% and 45.8-73.7%, respectively. The EHBF-MELD score had the highest specificity.

CONCLUSION

EHBF was significantly lower in the patients with ACLF compared to decompensated cirrhosis. The EHBF were closely related to the severity of HBV-ACLF and can be used for predicting the 90-day mortality rate of HBV-ACLF.

Noninvasive diagnosis of chemotherapy induced liver injury by LiMAx test--two case reports and a review of the literature

Background

Chemotherapy-induced liver injury is a well-known phenomenon after neoadjuvant therapy of liver metastasis and contributes to postoperative morbidity and mortality. Still there is no suitable test available to reliably determine functional impairment and hepatic regeneration after chemotherapy.

Case presentation

We report two cases of caucasian patients who underwent repeated liver function assessments using LiMAx (maximum liver function capacity), Indocyanine plasma disappearance rate and biochemical liver function parameters in the course of adjuvant oxaliplatin-based chemotherapy.

Both patients yielded a decrease from their initial liver function determined by LiMAx. Liver regeneration assessed functional recovery within 4 weeks in case of mild functional impairment after cessation of chemotherapy or within 8 weeks in case of major functional deterioration. Indocyanine plasma disappearance rate and biochemical parameters remained stable or without a clear trend in case of minor functional impairment. This is the first report using a dynamic liver function test to evaluate the impact and recovery from chemotherapy associated liver injury.

Conclusions

The LiMAx test might be a sensitive tool to diagnose mild functional impairment after chemotherapy when standard liver function tests have remained within normal ranges and might be capable to assess the course of regeneration after chemotherapy. This could be useful to optimize individual chemotherapy-free interval before liver surgery can be carried out safely.

Prognostic value of enzymatic liver function for the estimation of short-term survival of liver transplant candidates: a prospective study with the LiMAx test

LiMAx has been recently proposed as a new quantitative liver function test. Thus, we aimed to evaluate the diagnostic ability of LiMAx to assess short-term survival in liver transplant candidates and compare its performance to the model for end-stage liver disease (MELD) and indocyanine green plasma disappearance rate (ICG-PDR). Liver function of 167 chronic liver failure patients without hepatocellular carcinoma was prospectively investigated when they were evaluated for liver transplantation. Primary study endpoints were liver-related death within 6 months of follow-up. Within 6 months of follow-up, 18 patients died and 36 underwent liver transplantation. Median LiMAx results on evaluation day were significantly lower in patients who died (99 μg/kg/h vs. 55 μg/kg/h; P = 0.024), while median ICG-PDR results did not differ within both groups (4.4%/min vs. 3.5%/min; P = 0.159). LiMAx showed a higher negative predictive value (NPV: 0.93) as compared with ICG-PDR (NPV: 0.90) and the MELD (NPV: 0.91) in predicting risk of death within 6 months. In conclusion, LiMAx provides good prognostic information of liver transplant candidates. In particular, patients who are not at risk of death can be identified reliably by measuring actual enzymatic liver function capacity.

Predictors of quality of life in patients evaluated for liver transplantation

INTRODUCTION

Health-related quality of life (HRQOL) is severely impaired in advanced liver disease. The purpose of this study was to evaluate the impact of actual liver function and disease-specific factors on HRQOL of patients evaluated for liver transplantation.

PATIENTS AND METHODS

Disease-specific QOL was analyzed in 142 patients evaluated for liver transplantation using the German version of the Chronic Liver Disease Questionnaire (CLDQ-D). We performed quantitative liver function tests and collected clinical and demographical data of patients after their referral to our transplant department. Values were correlated with CLDQ-D scores.

RESULTS

Neither model for end-stage liver disease (MELD) nor dynamic liver function test results were related to quality of life. Serum albumin concentration was a strong but not independent factor correlated with global CLDQ-D (r = 0.269, p < 0.001). Independent predictors of global CLDQ-D were ascites and butyrylcholinesterase serum concentration (B = -0.486, p < 0.001 and B = 0.196, p = 0.002, respectively).

CONCLUSION

Actual liver function is not related to decreased quality of life, whereas ascites and hypoproteinemia represent the major factors influencing physical and social aspects of daily life in potential liver transplant candidates.

Noninvasive optical measurement of cerebral blood flow in mice using molecular dynamics analysis of indocyanine green

In preclinical studies of ischemic brain disorders, it is crucial to measure cerebral blood flow (CBF); however, this requires radiological techniques with heavy instrumentation or invasive procedures. Here, we propose a noninvasive and easy-to-use optical imaging technique for measuring CBF in experimental small animals. Mice were injected with indocyanine green (ICG) via tail-vein catheterization. Time-series near-infrared fluorescence signals excited by 760 nm light-emitting diodes were imaged overhead by a charge-coupled device coupled with an 830 nm bandpass-filter. We calculated four CBF parameters including arrival time, rising time and mean transit time of a bolus and blood flow index based on time and intensity information of ICG fluorescence dynamics. CBF maps were generated using the parameters to estimate the status of CBF, and they dominantly represented intracerebral blood flows in mice even in the presence of an intact skull and scalp. We demonstrated that this noninvasive optical imaging technique successfully detected reduced local CBF during middle cerebral artery occlusion. We further showed that the proposed method is sufficiently sensitive to detect the differences between CBF status in mice anesthetized with either isoflurane or ketamine–xylazine, and monitor the dynamic changes in CBF after reperfusion during transient middle cerebral artery occlusion. The near-infrared optical imaging of ICG fluorescence combined with a time-series analysis of the molecular dynamics can be a useful noninvasive tool for preclinical studies of brain ischemia.

In vivo multispectral photoacoustic and photothermal flow cytometry with multicolor dyes: a potential for real-time assessment of circulation, dye-cell interaction, and blood volume

Recently, photoacoustic (PA) flow cytometry (PAFC) has been developed for in vivo detection of circulating tumor cells and bacteria targeted by nanoparticles. Here, we propose multispectral PAFC with multiple dyes having distinctive absorption spectra as multicolor PA contrast agents. As a first step of our proof-of-concept, we characterized high-speed PAFC capability to monitor the clearance of three dyes (Indocyanine Green [ICG], Methylene Blue [MB], and Trypan Blue [TB]) in an animal model in vivo and in real time. We observed strong dynamic PA signal fluctuations, which can be associated with interactions of dyes with circulating blood cells and plasma proteins. PAFC demonstrated enumeration of circulating red and white blood cells labeled with ICG and MB, respectively, and detection of rare dead cells uptaking TB directly in bloodstream. The possibility for accurate measurements of various dye concentrations including Crystal Violet and Brilliant Green were verified in vitro using complementary to PAFC photothermal (PT) technique and spectrophotometry under batch and flow conditions. We further analyze the potential of integrated PAFC/PT spectroscopy with multiple dyes for rapid and accurate measurements of circulating blood volume without a priori information on hemoglobin content, which is impossible with existing optical techniques. This is important in many medical conditions including surgery and trauma with extensive blood loss, rapid fluid administration, and transfusion of red blood cells. The potential for developing a robust clinical PAFC prototype that is safe for human, and its applications for studying the liver function are further highlighted.

Optimal systemic hemodynamic stability for successful clinical outcomes after adult living-donor liver transplantation: prospective observational study

BACKGROUND AND AIM

Most living-donor liver transplantation (LDLT) recipients show characteristic systemic hemodynamics due to liver cirrhosis, and systemic hemodynamics after LDLT influenced postoperative graft function corresponding to outcomes. However, identities of optimal systemic hemodynamics for excellent outcomes and precise parameters for clinical strategy remain unclear.

METHODS

Therefore, we performed prospective study in adult LDLT recipients from 2003. Hemodynamic parameters were prospectively recorded, and were analyzed in 40 recipients classified into three groups: cirrhotic (group I-C) or non-cirrhotic recipients (group I-NC) with good outcomes, and cirrhotic recipients (group II-C) without good outcomes.

RESULTS

Group I-C retained characteristic hyperdynamics even after LDLT. However, absolute values of parameters revealed no significant differences between groups I-C and II-C, because group II-C also tended to show hyperdynamics. It is suggested that successful outcomes in cirrhotic recipients require maintenance of optimal hyperdynamic stability after LDLT, because cirrhotic vascular alterations still occurred. Because hemodynamic behaviors were different between groups I-C and I-NC, absolute values were also significantly different even in these successful two groups. Thus, absolute values themselves were not necessarily satisfactory for accurate evaluation of optimal hemodynamic stability. Cirrhotic hyperdynamics are symbolized in large blood volume (BV) circulated by high cardiac output (CO); therefore, we standardized CO against BV. CO/BV was significantly different between groups I-C and II-C, reflecting subtle variability of hyperdynamics in groups II-C, and was interestingly constant in the two successful groups. Therefore, CO/BV reliably evaluated optimal hemodynamic stability after LDLT, and accurately predicted outcomes.

CONCLUSION

Identification of inappropriate hemodynamics after LDLT is advantageous to further improve LDLT outcomes.

Stability of cirrhotic systemic hemodynamics ensures sufficient splanchnic blood flow after living-donor liver transplantation in adult recipients with liver cirrhosis

AIM: To investigate the correlation between systemic hemodynamics and splanchnic circulation in recipients with cirrhosis undergoing living-donor liver transplantation (LDLT), and to clarify how systemic hemodynamics impact on local graft circulation after LDLT.

METHODS: Systemic hemodynamics, indocyanine green (ICG) elimination rate (K_ICG) and splanchnic circulation were simultaneously and non-invasively investigated by pulse dye densitometry (PDD) and ultrasound. Accurate estimators of optimal systemic hyperdynamics after LDLT [i.e., balance of cardiac output (CO) to blood volume (BV) and mean transit time (MTT), defined as the time required for half the administered ICG to pass through an attached PDD sensor in the first circulation] were also measured. Thirty recipients with cirrhosis were divided into two groups based on clinical outcomes corresponding to postoperative graft function.

RESULTS: Cirrhotic systemic hyperdynamics characterized by high CO, expanded BV and low total peripheral resistance (TPR) were observed before LDLT. TPR reflecting cirrhotic vascular alterations was slowly restored after LDLT in both groups. Although no significant temporal differences in TPR were detected between the two groups, CO/BV and MTT differed significantly. Recipients with good outcomes showed persistent cirrhotic systemic hyperdynamics after LDLT, whereas recipients with poor outcomes presented with unstable cirrhotic systemic hyperdynamics and severely decreased K_ICG. Systemic hyperdynamic disorders after LDLT impacted on portal venous flow but not hepatic arterial flow.

CONCLUSION: We conclude that subtle systemic hyperdynamics disorders impact on splanchnic circulation, and that an imbalance between CO and BV decreases portal venous flow, which results in critical outcomes.

K(ICG) value, a reliable real-time estimator of graft function, accurately predicts outcomes in adult living-donor liver transplantation

Reliable monitoring enabling evaluation of graft function is crucial after living-donor liver transplantation (LDLT). A method to identify poor graft function at an early postoperative period would allow opportune intensive clinical management to bring about further improvements in LDLT outcomes. This study assessed the reliability of the indocyanine green (ICG) elimination rate constant (K(ICG)) value as an estimator of graft function and determined the actual temporal changes of K(ICG) after LDLT. K(ICG) values were measured using a noninvasive method in 30 adult recipients up to 28 days after LDLT. The receptor index (LHL15) based on liver scintigraphy, and graft parenchymal damage score based on histopathological findings were evaluated after LDLT and correlated well with simultaneous K(ICG). Thus, K(ICG) measured by noninvasive method was confirmed as accurately evaluating graft function. Changes of K(ICG) after LDLT in recipients with good graft function were maintained, after some falls in the early periods, and had a significant difference compared with those for recipients without good graft function; moreover, there were already significant differences in K(ICG) 24 hours after LDLT. Mean transit time reflecting systemic hemodynamics revealed that recipients without good outcomes fell into an unstable systemic hemodynamic state, and effective hepatic blood flow has a large influence on liver regeneration after LDLT. In conclusion, we suggested that K(ICG) values can predict clinical outcomes at the early postoperative period after LDLT by sharply reflecting the influence of systemic dynamics on splanchnic circulation.