Pressure Gradient Research Articles

Mass Cycle and Dynamics of a Virtual Quiescent Prominence

The mass cycle of solar prominences or filaments is still not completely understood. Researchers agree that these dense structures form by coronal in situ condensations and plasma siphoning from the underlying chromosphere. In the evaporation–condensation model siphoning arises due to evaporation of chromospheric plasma from localized footpoint heating, but this is challenging to justify observationally. Here, we simulate the reconnection–condensation model at extreme resolutions down to 20.8 km within a three-dimensional (3D) magnetohydrodynamic coronal volume. We form a draining, quiescent prominence and associated coronal rain simultaneously. We show that thermal instability—acting as a trigger for local condensation formation—by itself drives siphoning flows from the low corona without the need of any localized heating. In addition, for the first time, we demonstrate through a statistical analysis along more than 1000 magnetic field lines that cold condensations give rise to siphoning flows within magnetic threads. This siphoning arises from the strong pressure gradient along field lines induced by thermal instability. No correlation is found between siphoning flows and the prominence mass, making thermal instability the main in situ mass-collection mechanism. Our simulated prominence drains by gliding along strongly sheared, asymmetric, dipped magnetic arcades, and develops natural vertical fine structure in an otherwise horizontal magnetic field due to the magnetic Rayleigh–Taylor instability. By synthesising our data, our model shows remarkable agreement with observations of quiescent prominences such as its dark coronal cavity in extreme-ultraviolet emission channels, fine-scale vertical structure, and reconnection outflows, which, for the first time, have been self-consistently obtained as the prominence evolves.

Investigation of electromagnetic fluctuations in a magnetically screened high beta plasma

We report low-frequency electromagnetic turbulence in large-volume plasma devices in a region that receives magnetically screened plasma. The magnetic screen is produced by the activation of a large solenoid that generates a strong magnetic field ( BEEF ) transverse to the background axial magnetic field ( Bz ). The magnetic field strength variation in BEEF controls the plasma diffusion and is responsible for parametric profile modifications in large volume plasma devices. The turbulence is characterized by the observed features of an electromagnetic mode having frequency ordering in the lower hybrid range (f ci < f < f LH). The free energy source for the excited turbulence is believed to be the prevalent finite radial pressure gradient in the system. The excited electromagnetic mode shows typical scales for the wave number, k⊥ ∼ 0.13 cm−1 and frequency f ∼ 6 kHz and propagates with phase velocity comparable to ion acoustic velocity, C s in electron diamagnetic drift direction. It is believed that the low-frequency pressure gradient-driven electromagnetic mode exhibits coupling with the lower hybrid or whistler wave.

Solutions to a two-phase mass flow model with generalized drag

Drag plays a dominant role in the interfacial momentum exchange in mixture mass flows. In this study, we examine a general two-phase mass flow model formulated by Pudasaini (2012), which incorporates drag. This model describes the mass flow comprising a mixture of solid particles and viscous fluid moving downhill under the influence of gravity. We construct explicit, analytical, and numerical solutions to the model using the Lie symmetry method. These new solutions disclose the role of generalized drag in the dynamics of both solid particles and viscous fluid. The solutions show that solid and fluid phases undergo nonlinear evolution in a coupled manner. Additionally, the solutions demonstrate that increased drag results in a tighter binding between solid and fluid components. We also analyze the role of pressure gradients. The solutions reveal that when solid pressure dominates fluid pressure, solid velocity increases faster than fluid velocity. These findings align with our expectations, emphasizing the importance of analytical solution techniques in understanding the complex process of mixture mass transport in mountain slopes and valleys, thereby enhancing our understanding.

A detailed simulation study on radionuclide dispersion under spent fuel road transportation conditions: Effects of vessel type and coniferous vegetation growth

Vegetation barriers are an important environmental characteristic of spent fuel road transportation accidents. Spent fuel vessels may be affected by force majeure factors during transportation, which leads to damage to spent fuel assemblies and containers and can cause radionuclides to gradually release from assemblies to vessels to the external environment. In this work, considering the growth periods of coniferous vegetation barriers and vessel type, a radionuclide dispersion model based on computational fluid dynamics (CFD) was established by adding a decay term and a pressure loss term. The simulations showed that, first, compared to the small (Type-II) vessel, the effects of fluid flow around the large vessel (Type-I) have a more significant impact on radionuclide dispersion. The backflow around the Type-I vessel causes leaked radionuclides to disperse towards the vessel, and the larger the vessel is, the more significant the rise of the leaked radionuclide plume tail will be due to the increased negative pressure gradient area. Moreover, the area contaminated exceeding the maximum allowable concentration by radioactivity for the Type-I vessel is reduced gradually with the growth of coniferous vegetation barriers due to the weakening of the backflow effect by growing vegetation. Second, compared to vegetation barriers of 15 years and 23 years, the horizontal distance exceeding the maximum allowable concentration of the leaked 131I dispersion from Type II vessels near vegetation barriers for 12 years is the longest. The older the vegetation barrier is, the shorter the horizontal dispersion range, and the shape of radionuclide dispersion gradually transforms from flat to semicircular with vegetation barrier growth, but this could cause a greater radioactive accumulation effect near the leakage point, and the maximum concentration of leaked 131I reached 0.54kBq·m-3 for leaked radionuclides from the Type II vessel under vegetation barriers of 23 years. In addition, improvement suggestions based on the proposed method are presented, which will enable the Standards Institutes to apply the research methodologies described herein across various scenarios. Environmental ImplicationCompared to nonradioative pollutants, radioactive pollutants are intercepted by vegetation barriers and then migrate to the soil through leaves, stems, and roots, which can contaminate the surrounding environment. Considering the effects of vessel type and coniferous vegetation growth, a radionuclide dispersion model based on CFD was established. Suggestions for decontaminating radioactive pollution areas have been proposed based on the simulation results of hypothetical scenarios. The scenario applicability improvements based on the proposed model could assist relevant Standards Institutes to making improving measures.

Observed Global Mean State Changes Modulating the Collective Influence of the Tropical Atlantic and Indian Oceans on ENSO

Abstract In the last decades, many efforts have been made to understand how different tropical oceanic basins are able to impact El Niño–Southern Oscillation (ENSO). However, the collective connectivity among the tropical oceans and their associated influence on ENSO are less understood. Using a complex network methodology, the degree of collective connectivity among the tropical oceans is analyzed focusing on the detection of periods when the tropical basins collectively interact and the Atlantic and Indian basins influence the equatorial Pacific sea surface temperatures (SSTs). The background state for the periods of strong collective connectivity is also investigated. Our results show a marked multidecadal variability in the tropical interbasin connection, with periods of stronger and weaker collective connectivity. These changes seem to be modulated by changes in the North Atlantic Ocean mean state a decade in advance. In particular, strong connectivity occurs in periods with colder than average tropical North Atlantic surface ocean. Associated with this cooling, an anomalous convergence of the vertical integral of total energy flux (VIEF) takes place over the tropical north–west Atlantic, associated with anomalous divergence of VIEF over the equatorial eastern Pacific. In turn, an anomalous zonal surface pressure gradient over the tropical Pacific weakens the trades over the western equatorial Pacific. Consequently, a shallower thermocline emerges over the western equatorial Pacific, which can enhance thermocline feedbacks, the triggering of ENSO events, and therefore, ENSO variability. By construction, our results put forward opposite conditions for periods of weak tropical basin connectivity. These results have important implications for seasonal to decadal predictions.

Development of hepatic fibrosis in common variable immunodeficiency-related porto-sinusoidal vascular disorder.

Liver involvement is an increasingly recognised complication of common variable immunodeficiency (CVID). Nodular regenerative hyperplasia (NRH), a subgroup of porto-sinusoidal vascular disorder, and manifestations of portal hypertension (PH) unrelated to cirrhosis are the most common findings. Nonetheless, the evolution of liver disease over time remains unknown. Retrospective review of patients followed at the National Institutes of Health with CVID-related liver disease and liver biopsy from 1990 to 2020. Clinical, imaging and histological follow-up were recorded as part of clinical research protocols. Forty patients were included, with a median age of 37.5 years at initial biopsy, 73% presenting with clear evidence of NRH, and a median fibrosis stage of 1. At biopsy, median platelet count was 100 × 109/L, spleen size 19.5 cm, hepatic venous pressure gradient 9.5 mmHg and 37.5% of patients had signs of PH. Cumulative incidence of PH was 65% at 5 years. In a subgroup of 16 patients, a follow-up liver biopsy, performed at a median time of 3 years after the index biopsy, revealed an increase in fibrosis by ≥2 stages in 31% of cases and an increase to an overall stage of 2.2 (p = 0.001). No clinical or histological factors were associated with progression of fibrosis. In this CVID cohort, NRH is the most common initial histological finding; however, unexpectedly fibrosis progresses over time in a subgroup of patients. A better understanding of the underlying causal process of liver disease CVID might lead to improved outcomes.

Lateral Transport Controls the Tidally Averaged Gravitationally Driven Estuarine Circulation: Tidal Mixing Effects

Abstract In classic models of the tidally averaged gravitationally driven estuarine circulation, denser salty oceanic water moves up the estuary near the bottom, while less dense riverine water flows toward the ocean near the surface. Traditionally, it is assumed that the associated pressure gradient forces and salt advection are balanced by vertical mixing. This study, however, demonstrates that lateral (across the estuary width) transport processes are essential for maintaining the estuarine circulation. This is because for realistic estuarine bathymetry, the depth-integrated salt transport up the estuary is enhanced in the deeper estuary channel. A closed salt budget then requires the lateral transport of this excess salt in the deeper channel toward the estuarine flanks. To understand how such lateral transport affects the estuarine salt and momentum balances, we devise an idealized model with explicit lateral transport focusing on tidally averaged lateral mixing effects. Solutions for the along-estuary velocity and salinity are nondimensionalized to depend only on one single nondimensional parameter, referred to as the Fischer number, which describes the relative importance of lateral to vertical tidal mixing. For relatively strong lateral tidal mixing (greater Fischer number), salinity and velocity variations are predominantly vertical. For relatively weak lateral tidal mixing (smaller Fischer number), salinity and velocity variations are predominantly lateral. Overall, lateral transport greatly affects the estuarine circulation and controls the estuarine salinity intrusion length, which is demonstrated to scale inversely with the Fischer number.

An Increase in the Ratio of Brain Natriuretic Peptide to Peak Transvalvular Pressure Gradient Suggests Coexistence of Cardiovascular Complications in Elderly Aortic Stenosis Patients.

The aim of this study was to differentiate between elderly aortic stenosis (AS) patients with and without cardiovascular complications (CCs).In total, 156 consecutive patients with AS aged ≥ 70 years were enrolled. Patients were divided into 2 groups as follows: AS without CCs (group I; n = 110) and AS with CCs (group II; n = 46). Routine electrocardiographic and echocardiographic parameters, peak and mean transvalvular pressure gradients (TPGs), aortic valve area (AVA), brain natriuretic peptide (BNP) levels, and BNP/peak TPG ratio were measured.The mean ages in groups I and II were 80.4 ± 5.5 and 82.5 ± 7.2 years. Left ventricular hypertrophy was greater in group II than in group I. Left ventricular end-diastolic and end-systolic dimensions and left ventricular fractional shortening were normal in both groups. Peak and mean TPGs were greater in group II (67.2 ± 39.3 and 40.2 ± 26.4 mmHg) than in group I (52.0 ± 23.0 and 30.2 ± 13.9, both P < 0.005); however, the AVA showed no significant difference between the 2 groups. The median BNP levels were 65.9 and 433.7 pg/mL in groups I and II (P < 0.0001). A correlation between peak TPG and BNP levels was observed in both groups. The BNP/peak TPG ratio was < 3.0 in all patients of group I and ≥ 3.0 in almost all patients of group II (P< 0.0001). The area under the curve using BNP/peak TPG ratio was 0.9883.BNP and BNP/peak TPG ratio could differentiate between AS with and without CCs in elderly patients.

Thermodynamical impacts on the boundary layer imbalance during secondary eyewall formation

It is well realized that the planetary boundary layer (PBL) imbalance is essential for the secondary eyewall formation (SEF) in tropical cyclones (TCs). The purpose of this study is to investigate the thermodynamic processes in inducing the PBL imbalance. While the control run in an idealized simulation is capable of generating the SEF, simulations with varying fall speeds of raindrops (FSR) in the microphysics resulted in different outcomes for the formation of SEF. The SEF occurs only within a specific range of FSR relative to its default formulation in the model.The gradient wind equation in the PBL is used to diagnose the imbalance leading to SEF. In the case with a formation of SEF, a substantial downdraft induced by TC outer rainbands is observed, leading to positive agradient force (AF). Such downdraft favors the formation of a moat region. Furthermore, the adiabatic warming induced by the downdrafts also modifies the temperature field and the radial gradient of pressure field, contributing to the PBL imbalance. While previous studies have emphasized the importance of the broadening of tangential wind as a trigger for positive AF, our results highlight the importance of the local pressure gradient imbalance within the PBL.

Impact of the expansion ratio on the properties of hydrogen recirculation ejectors

Exploring the development characteristics and influencing factors of the mixing layer (ML) inside the hydrogen recirculation ejector is of great importance for enhancing the recirculation properties of the ejector and promoting green and sustainable energy development. However, the evolution of ML in the ejector and the transport and diffusion characteristics of the fluid are problematic, in particular, the influence of the expansion ratio on the properties of the ejector is unclear. Therefore, in this study, a CFD numerical model of an ejector was established to simulate the flow of fluids in the ejector. The evolution of ML was elucidated, and the interaction mechanism between the mixing and the recirculation performance of the ejector was revealed. The findings showed that the velocity difference is a significant driving force for the development of ML, and the formation of an adverse pressure gradient contributes to the diffusion of hydrogen and the rapid development of ML. The development process of ML in the ejector can be divided into three stages under the interaction of the velocity difference and the convective Mach number: the rapid growth stage, the slow growth stage, and the exponential growth stage. By studying the evolution of ML at different expansion ratios, it was found that there exists a critical expansion ratio for the ejector, which results in the largest of the non-mixing length ratio and the effective mixing thickness, the strongest relative mass transfer capability of the entrained flow, the fullest development of ML, and the optimal hydrogen recirculation performance.

Mapping global land conversion pressure to support conservation planning

Proactively identifying where land conversion might occur is critical to targeted and effective conservation planning. Previous efforts to map future habitat loss have largely focused on forested systems and have been limited in their consideration of drivers of loss. We developed a 1-km resolution, global map of land conversion pressure from multiple drivers, referred to as the conversion pressure index (CPI). The CPI combines past rates of anthropogenic change, as measured by temporal human modification maps, with suitability maps for potential future expansion by large-scale development. The CPI thus offers a new way to measure a cumulative gradient of anthropogenic pressure as opposed to categorical land cover change. We find that nearly 23% of land across 200 countries have relatively high conversion pressure, potentially impacting over 460 million ha of intact natural lands. We illustrate how this information can be used to identify areas for proactive conservation to avoid future loss and ensure that national commitments under the Kunming-Montreal Global Biodiversity and Paris Agreement Climate Frameworks are upheld.

Summer marine heatwaves in the tropical Indian Ocean associated with an unseasonable positive Indian Ocean Dipole event 2012

Marine heatwaves (MHWs) are anomalously warm events that profoundly affect climate change and local ecosystem. During the summer of 2012 (June–September), intense MHWs occurred in the tropical Indian Ocean (TIO) concurrently with an unseasonable positive Indian Ocean Dipole (pIOD) event. The MHW metrics (duration, frequency, cumulative intensity and maximum intensity) were characterized by northwestward–slanted patterns from west Australia to the Somalia coast. The analysis confirmed that these MHWs were closely associated with the unseasonable pIOD 2012. The weakening of Western North Pacific Subtropical High and strengthening of Australian High in spring induced an interhemispheric pressure gradient that drove two anticyclonic circulation patterns over the eastern TIO. The first anticyclonic circulation featured cross–equatorial wind anomalies from south of Java to the South China Sea/Philippine Sea, which led to strong upwelling off Sumatra–Java during the subsequent summer. The second anticyclonic circulation excited downwelling Rossby waves that propagated from the southeastern TIO to the western TIO. Thus, downwelling in the western pole and upwelling in the eastern pole led to a strong pIOD event peaking in summer, namely, the unseasonable pIOD 2012. These downwelling Rossby waves deepened the thermocline by more than 60 m and caused anomalous surface warming, thereby contributing to the occurrences of MHWs. With the development and peak of the unseasonable pIOD 2012, anomalous atmospheric circulation transported moisture from the TIO to the subtropical Western North Pacific (WNP), favoring a strong cyclonic anomaly that profoundly affected the summer monsoon rainfall over the subtropical WNP. This study provides some perspectives on the role of pIOD events in summer climate over the Indo–Northwest Pacific region.

Failure of Surgical Aortic Valve Prostheses: An Analysis of Heart Team Decisions and Postoperative Outcomes

Objectives: To analyze Heart Team decisions and outcomes following failure of surgical aortic valve replacement (SAVR) prostheses. Methods: Patients undergoing re-operations following index SAVR (Redo-SAVR) and those undergoing valve-in-valve transcatheter aortic valve replacement (ViV-TAVR) following SAVR were included in this study. Patients who underwent index SAVR and/or Redo-SAVR for endocarditis were excluded. Data are presented as medians and 25th–75th percentiles, or absolute numbers and percentages. Outcomes were analyzed in accordance to the VARC-3 criteria. Results: Between 01/2015 and 03/2021, 53 patients underwent Redo-SAVR, 103 patients ViV-TAVR. Mean EuroSCORE II was 5.7% (3.5–8.5) in the Redo-SAVR group and 9.2% (5.4–13.6) in the ViV group. In the Redo-SAVR group, 12 patients received aortic root enlargement (22.6%). Length of hospital and ICU stay was longer in the Redo-SAVR group (p &lt; 0.001; p &lt; 0.001), PGmax and PGmean were lower in the Redo-SAVR group as compared to the ViV-TAVR group (18 mmHg (10–30) vs. 26 mmHg (19–38), p &lt; 0.001) (9 mmHg (6–15) vs. 15 mmHg (9–21), p &lt; 0.001). A higher rate of paravalvular leakage was seen in the ViV-TAVR group (p = 0.013). VARC-3 Early Safety were comparable between the two populations (p = 0.343). Survival at 1 year and 5 years was 82% and 36% in the ViV-TAVR cohort and 84% and 77% in the Redo-SAVR cohort. The variables were patient age (OR 1.061; [95% CI 1.020–1.104], p = 0.004), coronary heart disease (OR 2.648; [95% CI 1.160–6.048], p = 0.021), and chronic renal insufficiency (OR 2.711; [95% CI 1.160–6.048], p = 0.021) showed a significant correlation to ViV-TAVR. Conclusions: Heart Team decisions are crucial in the treatment of patients with degenerated aortic bioprostheses and lead to a low mortality in both treatment paths thanks to patient-specific therapy planning. ViV-TAVR offers a treatment for elderly or intermediate-risk profile patients with comparable short-term mortality. However, this therapy is associated with increased pressure gradients and a high prevalence of paravalvular leakage. Redo-SAVR enables the surgical treatment of concomitant cardiac pathologies and allows anticipation for later VIV-TAVR by implanting the largest possible valve prostheses.

Back to Bernoulli: a simple formula for trans-stenotic pressure gradients and retrospective estimation of flow rates in cerebral venous disease

BackgroundVenous sinus stenosis can be associated with cerebrovascular disorders. Understanding the role of blood flow disturbances in these disorders is often hampered by the lack of patient-specific flow rates. Our...

Prevalence and prognostic value of zinc and selenium deficiency in advanced chronic liver disease.

Zinc and selenium are essential trace elements involved in important (patho)physiological processes. The prevalence and prognostic implications of zinc and selenium deficiency in patients with advanced chronic liver disease (ACLD) remain unknown. We determined serum zinc and selenium concentrations in 309 patients with ACLD undergoing hepatic venous pressure gradient (HVPG) measurement between 2019 and 2022. We evaluated the prevalence of zinc/selenium deficiency and assessed its association with severity of ACLD and liver-related events (LRE, i.e. first/further hepatic decompensation/liver-related death). Among 309 ACLD patients (median: age: 57 [IQR: 50-64], MELD: 11 [IQR: 9-16], HVPG: 17 [IQR: 11-20]), 73% (227) and 63% (195) were deficient in zinc and selenium, respectively. Decompensated (dACLD) patients showed significantly lower serum zinc (median: 48 [IQR: 38-59] vs. compensated, cACLD: 65 [IQR: 54-78], p < 0.001) and selenium levels (median: 4.9 [IQR 4.0-6.2] vs. cACLD: 6.1 [IQR 5.1-7.3], p < 0.001). Significant correlations of zinc/selenium levels were found with MELD (zinc: ρ = -0.498, p < 0.001; selenium: ρ = -0.295, p < 0.001), HVPG (zinc: ρ = -0.400, p < 0.001; selenium: ρ = -0.157, p = 0.006) and liver disease-driving mechanisms (IL6, bile-acid homeostasis). On multivariable analysis, low zinc/selenium levels, age and MELD remained independently associated with LRE. Zinc and selenium deficiencies are common in ACLD patients especially with higher MELD and HVPG. Low zinc and selenium levels independently predicted hepatic decompensation and liver-related death. The effect of zinc/selenium supplementation in ACLD should be investigated in future trials.

Theoretical investigation of threshold pressure gradient in hydrate-bearing clayey-silty sediments under combined stress and local thermal stimulation conditions

Due to the characteristics of smaller grain size and higher clay mineral content, the threshold pressure gradient (TPG) exists in multi-phase flow within hydrate-bearing clayey-silty sediments (HBCSS), which significantly affects the gas production from hydrate reservoirs. However, multi-phase flow through HBCSS relates to thermal-hydrological-mechanical coupling, leading to the understanding of TPG in HBCSS with complex pore structures and hydrate distribution is unclear. In this study, a theoretical TPG model of HBCSS is developed by considering the combined influences of effective stress, temperature increase, pore structures, hydrate saturation and its growth patterns. The proposed TPG model has been thoroughly validated using available experimental data. Moreover, the parameter sensitivity analysis is conducted based on this derived model, revealing a positive correlation between TPG and both effective stress and temperature increase. While TPG generally increases with higher hydrate saturation when other parameters are held constant, the relationship between TPG and hydrate saturation is non-monotonic. This observation suggests that TPG is impacted not only by hydrate saturation but also by other factors, including hydrate growth patterns and pore structures. The findings of this study establish a theoretical foundation for characterizing the nonlinear flow behavior during hydrate exploitation.

Role of splenic hepatic elastography ratio in differentiating non-cirrhotic portal fibrosis and chronic liver disease in children and adolescents.

Differentiation of Non-cirrhotic Portal Fibrosis (NCPF) from chronic liver disease (CLD) in children and adolescents with portal hypertension (PHT) is challenging especially in cases where liver stiffness measurement (LSM) and hepatic venous pressure gradient are higher. This objective of the current study was to evaluate the diagnostic accuracy of the splenic stiffness measurement (SSM)/LSM ratio in the diagnosis of NCPF. From January 2019 to December 2023, consecutive children and adolescents of 6months to 18years of age with PHT (CLD and NCPF) were prospectively enrolled. Transient elastography (TE) for SSM and LSM, upper gastrointestinal endoscopy (UGIE), liver biopsy/trans-jugular liver biopsy, abdominal imaging, and laboratory evaluation were done. The relationship of TE parameters for diagnosis of NCPF and CLD was evaluated. Receiver-operating characteristic (ROC) statistics were applied using R Studio-4.2.2 statistical software. One hundred and forty seven with CLD and 27 patients with NCPF were evaluated. Median age was 10.0 (IQR 2.4-14.0) years; 68.4% were males. The AUROC of SSM/LSM ratio was better (0.992, 95%CI 0.982-1.0001) than LSM (0.945, 95%CI0.913-0.977) and SSM (0.626, 95%CI0.258-0.489) for the diagnosis of NCPF. SSM/LSM ratio cut-off of 3.67 predicted NCPF with an excellent sensitivity (100%), specificity (95.9%), and diagnostic accuracy (95.91%). The AUROC of SSM/LSM ratio was excellent and outperformed other TE parameters in the subgroups, i.e., LSM between 10 and 20kPa (0.982, 95%CI 0.947-1.000), without clinically significant varices (CSV) (1.000, 95%CI 1.000-1.000) and with CSV (0.993, 95%CI 0.983-1.000). Diagnostic performance of SSM/LSM Ratio was better than LSM for discriminating NCPF from CLD using McNemar test (p = 0.01). The SSM/LSM ratio is an excellent tool in differentiating NCPF from CLD.

Prognostic implications of residual mild coarctation gradient after interventional repair.

There is limited data on the prognostic implications of residual mild coarctation (RMC) in patients with repaired native coarctation of the aorta (CoA). To explore the association of RMC with mid-term comorbidities in post-interventional patients, and the predictive value of the residual pressure gradient. The authors retrospectively analyzed 79 native CoA patients who received successful intervention at our hospital between October 2010 and June 2023. The outcomes of the study were late arterial hypertension (either raised blood pressure or commencement of hypotensive medications) only in normotensive patients at early follow-up and the composite mid-term comorbidities including new-onset aortic injury, re-stenosis, and re-intervention. At a median follow-up of 60months, late hypertension and mid-term comorbidities occurred in 16 (28.1%) and nine (11.4%) patients, respectively. Multivariate Cox proportional hazard regression analysis identified invasive peak systolic CoA pressure gradient (PSPG) as the best independent predictor of both outcomes. The maximally selected rank statistics indicated 10mm Hg as the best PSPG cut-off value for predicting late hypertension. Compared to patients with PSPG<11mm Hg, the cumulative event rates of both outcomes were higher in those with PSPG≥11mm Hg (log-rank test, p<.001 for both endpoints). PSPG≥11mmHg was proved to be the independent predictor of late hypertension with a significantly increased risk. In patients with non-surgical CoA repair, the post-interventional RMC and PSPG ≥11mm Hg are important predictors of clinical comorbidities at mid-term follow-up.

Combination of carvedilol with variceal band ligation in prevention of first variceal bleed in Child-Turcotte-Pugh B and C cirrhosis with high-risk oesophageal varices: the ‘CAVARLY TRIAL’

ObjectivesBeta-blockers and endoscopic variceal band ligation (VBL) have been preferred therapies for primary prophylaxis of variceal bleeding. However, the choice of therapy in patients with advanced liver disease with high-risk...

The Balloon Catheter Method and the End-hole Catheter Method in the Measurement of Hepatic Venous Pressure Gradient: a Comparative Study.

This study aims to evaluate the differences between The balloon catheter method and End-hole Catheter Method in measuring hepatic venous pressure gradient (HVPG) among cirrhosis patients. From October 2017 to January 2024, patients who underwent HVPG measurements using both methods were consecutively included. HVPGs obtained from both methods were compared with the portal vein pressure gradient (PPG) obtained via transjugular intrahepatic portosystemic shunt (TIPS) using paired comparisons. Additionally, the consistency and predictive ability for bleeding risk of the two methods, as well as the impact of intrahepatic veno-venous shunt (IHVS), were analyzed. The study enrolled 145 patients, each of whom had HVPG measured by both methods. PPG was measured in 61 patients. There was a statistically significant difference between the PPGs and HVPGs measured by both the balloon catheter method and the end-hole catheter method (P < 0.001), with the HVPG mean values obtained by the end-hole catheter method being closer to the PPGs. In the non-IHVS group, no significant statistical difference was found between the two methods (P = 0.071). In contrast, the IHVS group showed a significant difference (P < 0.001), with a mean difference of 2.98 ± 4.03mmHg. When IHVS was absent, the measurement results from the end-hole catheter method and the balloon catheter method were found to be highly correlated. The end-hole catheter method has a higher screening capability for patients at risk of bleeding compared to the balloon catheter method (75.90% vs. 72.86%). HVPG measurements using either the balloon catheter method or end-hole catheter method showed significant difference with the PPG. The end-hole catheter method has a higher screening capability for patients at risk of bleeding, and IHVS could lead to lower HVPG measurements with The balloon catheter method.