Portal pressure is of significant prognostic value in primary biliary cholangitis

Comparative diagnostic efficacy of two-dimensional shear wave and transient elastography in predicting the risk of esophagogastric varices and histological staging in patients with primary biliary cholangitis

BACKGROUND

This study aimed to compare the diagnostic efficacy of Two-dimensional shear wave elastography (2D-SWE) with that of transient elastography (TE) in predicting the risk of esophagogastric varices and histological staging in patients with primary biliary cholangitis (PBC).

METHODS

This single-center prospective study enrolled the patients with PBC diagnosed by liver biopsy following 2D-SWE and TE. Receiver operating characteristic (ROC) curves were constructed for SWE-liver stiffness measurement (LSM) and TE-LSM to assess their diagnostic efficacy for histological staging ≥ stage 2, ≥ stage 3, and = stage 4. The diagnostic efficacy and accuracy of SWE-LSM were compared with those of the Baveno VI criteria for detecting esophagogastric varices. Additionally, the impact of different laboratory parameters on SWE-LSM was analyzed.

RESULTS

We evaluated 77 patients (median age, 52 years (range: 16 - 75 years), 66 females). ROC curves constructed using TE-LSM and SWE-LSM demonstrated similar diagnostic efficacy for histological staging ≥ stage 2 (area under the curve [AUC]: 0.824 vs. 0.823 for TE-LSM and SWE-LSM, respectively, p = 0.9764), ≥ stage 3 (AUC: 0.918 vs. 0.907 for TE-LSM and SWE-LSM, respectively, p = 0.6443), and = stage 4 (AUC: 0.907 vs. 0.902 for TE-LSM and SWE-LSM, respectively, p = 0.8763). Additionally, while there was no significant difference in the diagnostic efficacy between the two methods for detecting esophagogastric varices (Z = 1.516, p = 0.1296), 2D-SWE had a slightly higher diagnostic accuracy than TE (61.8% vs. 76.4%). Transaminases and bilirubin levels had little influence on SWE-LSM.

CONCLUSION

2D-SWE exhibited comparable performance to TE in predicting the risk of esophagogastric varices and histological staging.

Portal Vein Pressure Estimation and Portal Hypertension Discrimination Based on Subharmonic Scattering of Ultrasound Contrast Agent Microbubbles

OBJECTIVE

The acquisition of real-time portal vein pressure (PVP) is important for portal hypertension (PH) discrimination to monitor disease progress and select treatment options. To date, the PVP evaluation approaches are either invasive or noninvasive but with less stability and sensitivity.

METHODS

We customized an open ultrasound scanner to explore in vitro and in vivo the ultrasound contrast agent SonoVue microbubbles' subharmonic characteristics with acoustic pressure and local ambient pressure, and obtained promising results of PVP measurements in canine models with induced PH by ligation or embolization of portal vein.

RESULTS

In in vitro experiments, the highest correlations between the subharmonic amplitude of SonoVue microbubbles and ambient pressure were observed at acoustic pressures of 523 kPa and 563 kPa (r = -0.993, -0.993, P<0.05, respectively). The correlation coefficients between absolute subharmonic amplitudes and PVP (10.7-35.4 mmHg) were the highest among existing studies using microbubbles as pressure sensors (r values ranged from -0.819 to -0.918). The PH (>16 mmHg) diagnostic capacity also achieved a high level (563 kPa, sensitivity = 93.3%, specificity = 91.7%, accuracy = 92.6%).

CONCLUSION

This study proposes a promising measurement for PVP with the highest accuracy, sensitivity, and specificity in an in vivo model compared to existing studies. Future investigations are planned to assess the feasibility of this technique in clinical practice.

SIGNIFICANCE

This is the first study that comprehensively investigates the role of the subharmonic scattering signals from SonoVue microbubbles in evaluating PVP in vivo. It represents a promising alternative to invasive measurements for portal pressure.

Spleen stiffness measurement predicts decompensation and rules out high-risk oesophageal varices in primary biliary cholangitis

Background & Aims

Primary biliary cholangitis (PBC) may lead to portal hypertension (PH). Spleen stiffness measurement (SSM) by vibration-controlled transient elastography accurately predicts PH. We aimed to assess SSM role in stratifying the risk of liver decompensation in PBC.

Methods

In this monocentric, prospective, cross-sectional study, we included 114 patients with PBC who underwent liver stiffness measurement (LSM) and SSM. In total, 78 and 33 patients underwent two and three sequential vibration-controlled transient elastography examinations, respectively (longitudinal study). Screening for high-risk oesophageal varices by oesophagogastroduodenoscopy was performed according to guidelines and proposed to all patients with SSM >40 kPa.

Results

Among the 114 patients, 20 (17%) had LSM ≥10 kPa, whereas 17 (15%) had SSM >40 kPa. None of the patients with SSM ≤40 kPa had high-risk oesophageal varices, compared with three of 14 patients with SSM >40 kPa (21%; three refused endoscopy); any-size oesophageal varices were found in nine of 14 patients (64%). During a median follow-up of 15 months (IQR 10-31 months), five (4%) patients developed liver decompensation. The probability of liver decompensation was significantly higher among patients with both LSM ≥10 kPa and SSM >40 kPa: 41% at 24 months vs. 0% in other patient groups (i.e. LSM <10 kPa and SSM ≤40 kPa, or LSM ≥10 kPa and SSM ≤40 kPa, or LSM <10 kPa and SSM >40 kPa) (p <0.0001). Among the 78 patients undergoing longitudinal evaluation, four of nine patients (44%) with SSM increase during follow-up experienced liver decompensation, whereas none of those with stable LSM and SSM had liver decompensation.

Conclusions

Both LSM and SSM predict liver decompensation in patients with PBC. SSM ≤40 kPa rules out high-risk oesophageal varices and might be used in combination with LSM to improve the prediction of PH-related complications.

Impact and implications

Spleen stiffness measurement by vibration-controlled transient elastography accurately predicts portal hypertension in patients with chronic viral hepatitis. The present study is the first to demonstrate that in primary biliary cholangitis the combination of liver stiffness and spleen stiffness measurement can significantly improve risk stratification by predicting liver decompensation. Moreover, when spleen stiffness is combined with liver stiffness measurement and platelet count, it aids in identifying individuals with a low probability of having high-risk oesophageal varices, thereby allowing the avoidance of unnecessary endoscopy examinations. Further validation of our results in larger cohorts of patients with primary biliary cholangitis is needed to implement spleen stiffness measurement in clinical practice.

A Dynamic Prediction Model Supporting Individual Life Expectancy Prediction Based on Longitudinal Time-Dependent Covariates

In the field of clinical chronic diseases, common prediction results (such as survival rate) and effect size hazard ratio (HR) are relative indicators, resulting in more abstract information. However, clinicians and patients are more interested in simple and intuitive concepts of (survival) time, such as how long a patient may live or how much longer a patient in a treatment group will live. In addition, due to the long follow-up time, resulting in generation of longitudinal time-dependent covariate information, patients are interested in how long they will survive at each follow-up visit. In this study, based on a time scale indicator-restricted mean survival time (RMST)-we proposed a dynamic RMST prediction model by considering longitudinal time-dependent covariates and utilizing joint model techniques. The model can describe the change trajectory of longitudinal time-dependent covariates and predict the average survival times of patients at different time points (such as follow-up visits). Simulation studies through Monte Carlo cross-validation showed that the dynamic RMST prediction model was superior to the static RMST model. In addition, the dynamic RMST prediction model was applied to a primary biliary cirrhosis (PBC) population to dynamically predict the average survival times of the patients, and the average C-index of the internal validation of the model reached 0.81, which was better than that of the static RMST regression. Therefore, the proposed dynamic RMST prediction model has better performance in prediction and can provide a scientific basis for clinicians and patients to make clinical decisions.