Hemorheology in patients with liver cirrhosis: special emphasis on its relation to severity of esophageal variceal bleeding

One in four patients with gastrointestinal bleeding develops shock or hemodynamic instability: A systematic review and meta-analysis

BACKGROUND

Hemodynamic instability and shock are associated with untoward outcomes in gastrointestinal bleeding. However, there are no studies in the existing literature on the proportion of patients who developed these outcomes after gastrointestinal bleeding.

AIM

To determine the pooled event rates in the available literature and specify them based on the bleeding source.

METHODS

The protocol was registered on PROSPERO in advance (CRD42021283258). A systematic search was performed in three databases (PubMed, EMBASE, and CENTRAL) on 14th October 2021. Pooled proportions with 95%CI were calculated with a random-effects model. A subgroup analysis was carried out based on the time of assessment (on admission or during hospital stay). Heterogeneity was assessed by Higgins and Thompson's I2 statistics. The Joanna Briggs Institute Prevalence Critical Appraisal Tool was used for the risk of bias assessment. The Reference Citation Analysis (https://www.referencecitationanalysis.com/) tool was applied to obtain the latest highlight articles.

RESULTS

We identified 11589 records, of which 220 studies were eligible for data extraction. The overall proportion of shock and hemodynamic instability in general gastrointestinal bleeding patients was 0.25 (95%CI: 0.17-0.36, I2 = 100%). In non-variceal bleeding, the proportion was 0.22 (95%CI: 0.14-0.31, I2 = 100%), whereas it was 0.25 (95%CI: 0.19-0.32, I2 = 100%) in variceal bleeding. The proportion of patients with colonic diverticular bleeding who developed shock or hemodynamic instability was 0.12 (95%CI: 0.06-0.22, I2 = 90%). The risk of bias was low, and heterogeneity was high in all analyses.

CONCLUSION

One in five, one in four, and one in eight patients develops shock or hemodynamic instability on admission or during hospitalization in the case of non-variceal, variceal, and colonic diverticular bleeding, respectively.

Machine learning-based model for predicting the esophagogastric variceal bleeding risk in liver cirrhosis patients

BACKGROUND

Liver cirrhosis patients are at risk for esophagogastric variceal bleeding (EGVB). Herein, we aimed to estimate the EGVB risk in patients with liver cirrhosis using an artificial neural network (ANN).

METHODS

We included 999 liver cirrhosis patients hospitalized at the Beijing Ditan Hospital, Capital Medical University in the training cohort and 101 patients from Shuguang Hospital in the validation cohort. The factors independently affecting EGVB occurrence were determined via univariate analysis and used to develop an ANN model.

RESULTS

The 1-year cumulative EGVB incidence rates were 11.9 and 11.9% in the training and validation groups, respectively. A total of 12 independent risk factors, including gender, drinking and smoking history, decompensation, ascites, location and size of varices, alanine aminotransferase (ALT), γ-glutamyl transferase (GGT), hematocrit (HCT) and neutrophil-lymphocyte ratio (NLR) levels as well as red blood cell (RBC) count were evaluated and used to establish the ANN model, which estimated the 1-year EGVB risk. The ANN model had an area under the curve (AUC) of 0.959, which was significantly higher than the AUC for the North Italian Endoscopic Club (NIEC) (0.669) and revised North Italian Endoscopic Club (Rev-NIEC) indices (0.725) (all P <  0.001). Decision curve analyses revealed improved net benefits of the ANN compared to the NIEC and Rev-NIEC indices.

CONCLUSIONS

The ANN model accurately predicted the 1-year risk for EGVB in liver cirrhosis patients and might be used as a basis for risk-based EGVB surveillance strategies.

Considerations for Physiologically Based Modeling in Liver Disease: From Nonalcoholic Fatty Liver (NAFL) to Nonalcoholic Steatohepatitis (NASH)

Nonalcoholic fatty liver disease (NAFLD), representing a clinical spectrum ranging from nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis (NASH), is rapidly evolving into a global pandemic. Patients with NAFLD are burdened with high rates of metabolic syndrome-related comorbidities resulting in polypharmacy. Therefore, it is crucial to gain a better understanding of NAFLD-mediated changes in drug disposition and efficacy/toxicity. Despite extensive clinical pharmacokinetic data in cirrhosis, current knowledge concerning pharmacokinetic alterations in NAFLD, particularly at different stages of disease progression, is relatively limited. In vitro-to-in vivo extrapolation coupled with physiologically based pharmacokinetic and pharmacodynamic (IVIVE-PBPK/PD) modeling offers a promising approach for optimizing pharmacologic predictions while refining and reducing clinical studies in this population. Use of IVIVE-PBPK to predict intra-organ drug concentrations at pharmacologically relevant sites of action is particularly advantageous when it can be linked to pharmacodynamic effects. Quantitative systems pharmacology/toxicology (QSP/QST) modeling can be used to translate pharmacokinetic and pharmacodynamic data from PBPK/PD models into clinically relevant predictions of drug response and toxicity. In this review, a detailed summary of NAFLD-mediated alterations in human physiology relevant to drug absorption, distribution, metabolism, and excretion (ADME) is provided. The application of literature-derived physiologic parameters and ADME-associated protein abundance data to inform virtual NAFLD population development and facilitate PBPK/PD, QSP, and QST predictions is discussed along with current limitations of these methodologies and knowledge gaps. The proposed methodologic framework offers great potential for meaningful prediction of pharmacological outcomes in patients with NAFLD and can inform both drug development and clinical practice for this population.

A novel prognostic model for predicting the risk of first variceal hemorrhage in patients with HBV-related cirrhosis

Background

Variceal hemorrhage (VH) is a life-threatening complication of cirrhosis. An accurate VH risk evaluation is critical to determine appropriate prevention strategies. We aimed to develop an individualized prediction model to predict the risk of first VH in hepatitis B virus (HBV)-related cirrhotic patients.

Methods

A nomogram was developed based on a retrospective analysis of 527 consecutive HBV-related cirrhotic patients with gastroesophageal varices (GEVs). The nomogram evaluation was performed using the area under the receiver operating characteristic curve (AUC), concordance index (C-index), calibration plot, and decision curve analysis (DCA). The results were verified using an external cohort (n = 187).

Results

We developed a nomogram based on clinical and endoscopic features, including the size of varices, red wale marks, ascites, spleen thickness, γ-glutamyltransferase, and hematocrit. The C-index of the nomogram in the derivation and validation cohort was 0.806 and 0.820, respectively, and the calibration plot fitted well. Compared with those of the North Italian Endoscopic Club (NIEC) and revised NIEC indexes, the AUC (derivation cohort: 0.822 vs. 0.653 vs. 0.713; validation cohort: 0.846 vs. 0.685 vs. 0.747) and DCA curves of this nomogram were better. Further, based on the risk scores, patients were classified into low-, medium-, and high-risk groups, and significant differences were noted in VH incidence among the three risk groups (P <0.001 for each cohort).

Conclusions

An effective individualized nomogram to predict the risk of first VH in HBV-related GEV patients was established, which can assist clinicians in developing more appropriate prevention strategies.

Hemorheological Alteration in Patients with Cirrhosis Clinically Diagnosed with Portal Vein System Thrombosis After Splenectomy

Background

Portal vein system thrombosis (PVST) is a common and serious complication after splenectomy. Key factors, including wider diameters of the portal vein, decreased liver function, and high flow volume of portosystemic collateral vessel, are recognized PVST risks. Relationships between PVST and altered hemorheology, including increased plasma viscosity, remain unclear. We investigated hemorheological alterations and explored risk factors of PVST in patients with cirrhosis after splenectomy.

Material/Methods

Data on patients with cirrhosis who underwent splenectomy were collected retrospectively from January 2018 to June 2020. Color Doppler ultrasonography was performed after splenectomy. Hemorheological indexes were compared between groups. Receiver operating characteristic (ROC) analysis was conducted to analyze risk factor cutoff values. Univariate and multivariate analyses were conducted to explore risk factors of PVST.

Results

A total of 50 patients were divided into a PVST group (n=30) and control group (n=20). Hemorheological indexes of activated partial thromboplastin time, fibrinogen degradation products (FDP), D-dimer, middle shear rates 50 and 30, low shear rates 5 and 1, and hematocrit in the PVST group were significantly higher than those of the control group (P<0.05). FDP and low shear rate 1 were found to be risk factors of PVST after splenectomy by multivariate analysis. ROC analysis showed that the cutoff points for FDP and low shear rate 1 were ≥38.6 ug/mL and ≥16.855 mPa.s, respectively.

Conclusions

PVST after splenectomy is closely related to hemorheological alteration. FDP and low shear rate 1 may be valuable markers of PVST.

Hemorheological and Microcirculatory Factors in Liver Ischemia-Reperfusion Injury-An Update on Pathophysiology, Molecular Mechanisms and Protective Strategies

Hepatic ischemia-reperfusion injury (IRI) is a multifactorial phenomenon which has been associated with adverse clinical outcomes. IRI related tissue damage is characterized by various chronological events depending on the experimental model or clinical setting. Despite the fact that IRI research has been in the spotlight of scientific interest for over three decades with a significant and continuous increase in publication activity over the years and the large number of pharmacological and surgical therapeutic attempts introduced, not many of these strategies have made their way into everyday clinical practice. Furthermore, the pathomechanism of hepatic IRI has not been fully elucidated yet. In the complex process of the IRI, flow properties of blood are not neglectable. Hemorheological factors play an important role in determining tissue perfusion and orchestrating mechanical shear stress-dependent endothelial functions. Antioxidant and anti-inflammatory agents, ischemic conditioning protocols, dynamic organ preservation techniques may improve rheological properties of the post-reperfusion hepatic blood flow and target endothelial cells, exerting a potent protection against hepatic IRI. In this review paper we give a comprehensive overview of microcirculatory, rheological and molecular–pathophysiological aspects of hepatic circulation in the context of IRI and hepatoprotective approaches.

Low Fibrinogen Levels Are Associated with Bleeding After Varices Ligation in Thrombocytopenic Cirrhotic Patients

INTRODUCTION AND AIM

EVBL is a procedure frequently performed in cirrhotic patients for primary prophylaxis of bleeding. Patients with cirrhosis display various degrees of alteration of common coagulation parameters, and it is not known whether these alterations may predict post-EVBL bleeding. To evaluate factors predictive of post-endoscopic variceal band ligation (EVBL) bleeding in cirrhotic patients with thrombocytopenia.

METHODS

We included 109 patients with cirrhosis undergoing EVBL for primary prophylaxis of variceal bleeding. Common coagulation parameters (INR, fibrinogen levels) and complete haemogram were obtained in all patients and evaluated subdividing patients in bleeders and non bleeders following EVBL.

RESULTS

The incidence of post-EVBL bleeding was 5.5% (6 patients). INR and platelet counts, considered as continuous or dichotomous variables according to common cut-offs (i.e., INR&gt;1.5, platelet count &lt;50x109/L) were not predictors of post-EVBL bleeding. Patients who bled had significantly lower fibrinogen levels [146 mg/dL (98 - 262) versus 230 mg/dL (104 - 638), P=0.009], and no other biochemical or clinical predictors of bleeding were identified. A fibrinogen cut-off of 179 mg/dL had 98.6% negative predictive value for bleeding.

CONCLUSION

low fibrinogen levels are associated with an increased risk of bleeding following prophylactic EVBL in cirrhotic patients, and might be used to stratify patients' risk. However, due to their preliminary nature, these findings need to be confirmed in larger populations.

Hemorheological Alteration in Patients Clinically Diagnosed with Chronic Liver Diseases

Since liver function is changed by chronic liver diseases, chronic liver disease can lead to different hemorheological alterations during the course of the progression. This study aims to compare alterations in whole blood viscosity in patients with chronic liver disease, focusing on the gender effect. Chronic liver diseases were classified into three categories by patient's history, serologic markers, and radiologic findings: nonalcoholic fatty liver disease (NAFLD) (n = 63), chronic viral hepatitis B and C (n = 50), and liver cirrhosis (LC) (n = 35). Whole blood viscosity was measured by automated scanning capillary tube viscometer, while liver stiffness was measured by transient elastography using FibroScan®. Both systolic and diastolic whole blood viscosities were significantly lower in patients with LC than NAFLD and chronic viral hepatitis (P < 0.001) in male patients, but not in female patients. In correlation analysis, there were inverse relationships between both systolic and diastolic whole blood viscosity and liver stiffness (systolic: r = -0.25, diastolic: r = -0.22). Whole blood viscosity was significantly lower in male patients with LC than NAFLD or chronic viral hepatitis. Our data suggest that whole blood viscosity test can become a useful tool for classifying chronic liver disease and determining the prognosis for different types of chronic liver diseases.

Near-infrared spectroscopy for medical applications: Current status and future perspectives

The near-infrared radiation (NIR) window, also known as the "optical window" or "therapeutic window", is the range of wavelengths that has the maximum depth of penetration in tissue. Indeed, because NIR is minimally absorbed by water and hemoglobin, spectra readings can be easily collected from the body surface. Recent reports have shown the potential of NIR spectroscopy in various medical applications, including functional analysis of the brain and other tissues, as well as an analytical tool for diagnosing diseases. The broad applicability of NIR spectroscopy facilitates the diagnosis and therapy of diseases as well as elucidating their pathophysiology. This review introduces recent advances and describes new studies in NIR to demonstrate potential clinical applications of NIR spectroscopy.

A semi-mechanistic model to predict the effects of liver cirrhosis on drug clearance

BACKGROUND AND OBJECTIVE

Liver cirrhosis is characterized by a decrease in functional hepatocytes, lowered circulating levels of plasma proteins and alterations in blood flow due to the development of portacaval shunts. Depending on the interplay between these parameters and the characteristics of an administered drug, varying degrees of impaired systemic clearance and first-pass metabolism are anticipated. The Simcyp Population-based ADME Simulator has already been used successfully to incorporate genetic, physiological and demographic attributes of certain subgroups within healthy populations into in vitro-in vivo extrapolation (IVIVE) of xenobiotic clearance. The objective of this study was to extend population models to predict systemic and oral drug clearance in relation to the severity of liver cirrhosis.

METHODS

Information on demographics, changes in hepatic blood flow, cytochrome P450 enzymes, liver size, plasma protein binding and renal function was incorporated into three separate population libraries. The latter corresponded to Child-Pugh scores A (mild), B (moderate) and C (severe) liver cirrhosis. These libraries, together with mechanistic IVIVE within the Simcyp Simulator, were used to predict the clearance of intravenous and oral midazolam, oral caffeine, intravenous and oral theophylline, intravenous and oral metoprolol, oral nifedipine, oral quinidine, oral diclofenac, oral sildenafil, and intravenous and oral omeprazole. The simulated patients matched the clinical studies as closely as possible with regard to demographics and Child-Pugh scores. Predicted clearance values in both healthy control and liver cirrhosis populations were compared with observed values, as were the fold increases in clearance values between these populations.

RESULTS

There was good agreement (lack of statistically significant difference, two-tailed paired t-test) between observed and predicted clearance ratios, with the exception of those for two studies of intravenous omeprazole. Predicted clearance ratios were within 0.8- to 1.25-fold of observed ratios in 65% of cases (range 0.34- to 2.5-fold).

CONCLUSION

The various drugs that were studied showed different changes in clearance in relation to disease severity, and a 'one size fits all' solution does not exist without considering the multiple sources of the changes. Predictions of the effects of liver cirrhosis on drug clearance are of potential value in the design of clinical studies during drug development and, clinically, in the assessment of likely dosage adjustment.

Plasma viscosity changes in patients with liver cirrhosis

OBJECTIVES

Plasma viscosity (PV) is a major determinant of capillary blood flow through the microcirculation, which, if impaired, can result in potentially important clinical sequelae. The objectives of this study were to investigate the alterations of PV values in different stages of cirrhosis, and to determine if any change in PV correlates with Child score or Model for End-Stage Liver Disease (MELD) score or has any prognostic significance.

METHOD

The study included 92 patients with cirrhosis and 28 healthy volunteers. Upper endoscopic and ultrasonographic examinations of the patients were obtained. Serum biochemistry fibrinogen, complete blood count, C-reactive protein (CRP), and lipid profile were performed. PV was determined using a rotational viscosimeter.

RESULTS

PV decreased with the progression in Child scores (Child A: 1.46 +/- 0.20 mPa-s, Child B: 1.33 +/- 0.21 mPa-s, Child C: 1.12 +/- 0.15 mPa-s), (P < 0.001). A similar change was detected between the MELD score and PV (P < 0.001). There was a positive correlation between the total protein, albumin and plasma viscosity in the control group, but a similar relationship was not found in cirrhotic patients. History of hepatic encephalopathy (30 of 92 patients) was independently associated with decreased PV (P = 0.003).

CONCLUSION

We observed that increasing Child and MELD scores were significantly associated with lower PV levels irrespective of biochemical and hematologic values. These observations support the concept that hemorheologic changes in cirrhotic patients might be either the cause or the result of a pathophysiological process, and it may not be easy to distinguish between these two possibilities.