Change In Pressure Gradient Research Articles

Reductions in bilateral transverse sinus pressure gradients with unilateral transverse venous sinus stenting for idiopathic intracranial hypertension

BackgroundVenous sinus stenting is an effective treatment for papilledema associated with idiopathic intracranial hypertension (IIH). It is unclear whether unilateral transverse-sigmoid sinus (TSS) stenting adequately decompresses the contralateral TSS system...

Transjugular intrahepatic portosystemic shunt for hepatic sinusoidal obstruction syndrome associated with consumption of Gynura segetum

BackgroundTo evaluate the efficacy and safety of transjugular intrahepatic portosystemic shunt (TIPS) on hepatic sinusoidal obstruction syndrome (HSOS) associated with consumption of Gynura segetum (GS).MethodsWe retrospectively reviewed 9 consecutive patients with GS-related HSOS who were refractory to supportive treatment and underwent TIPS at our institution between January 2014 and September 2019. The patients were evaluated for safety and efficacy, including TIPS complications and changes in portosystemic pressure gradient (PPG), ascites, total bilirubin, liver size and portal vein diameter.ResultsTIPS procedures were performed successfully in the 9 patients, and no technically-related complications due to the TIPS procedure were recorded. The PPG was improved by TIPS in all patients (mean PPG before TIPS, 30.4 ± 5.2 vs. 13.0 ± 4.1 mm Hg post-TIPS, P = 0.008). One patient who was lost to follow-up, whereas the remaining 8 patients survived with a median follow-up period of 12 months (range 5–39 months). Although the total bilirubin was significantly increased 5–7 days after TIPS compared with that before the procedure (3.57 ± 1.58 vs. 4.82 ± 2.06 mg/dl, P = 0.017), it returned to baseline levels at 1-month follow-up (3.53 ± 2.72 vs. 4.82 ± 2.06 mg/dl, P = 0.401). The patients experienced complete resolution or noticeable reduction of ascites (P < 0.001), significant reduction of liver size (16.7 ± 2.2 vs. 13.7 ± 1.7 cm, P = 0.018), and significant enlargement of the portal trunk (10.7 ± 2.5 vs. 13.4 ± 2.4 mm, P = 0.017) after TIPS compared to the pre-TIPS state.ConclusionTIPS may offer a potentially useful treatment for the GS-related HSOS.

Sex difference in pulmonary hypertension in the evaluation by exercise echocardiography.

Male patients with pulmonary hypertension have poor survival than their female counterparts. Poor right ventricular function in men may be one of the major determinants of poor prognosis. This study aimed to investigate the difference in hemodynamics during exercise between men and women by exercise echocardiography. Consecutive patients with pulmonary hypertension who underwent right heart catheterization were enrolled, and survival was analyzed. In patients who underwent exercise echocardiography, the change in tricuspid regurgitation pressure gradient during exercise was calculated at multiple stages (low-, moderate-, and high-load exercise), and the mortality was also recorded. In a total of 93 patients, although there were no differences in pulmonary artery pressure and vascular resistance between sexes, male patients showed poor survival. In patients with exercise echocardiography, change in tricuspid regurgitation pressure gradient at low-load (25 W) exercise was significantly lower in men, although that at maximum-load exercise was not different between men and women. In the Kaplan–Meier analysis, in a median follow-up duration of 1760 days, male patients and those with lower change in tricuspid regurgitation pressure gradient at low-load exercise showed poorer survival (P = 0.002 and 0.026, respectively). In the Cox proportional hazards analysis, the change in tricuspid regurgitation pressure gradient at low-load exercise was independently associated with poor survival after adjustment for age and sex. In conclusion, a lower change in tricuspid regurgitation pressure gradient at low-load exercise was observed in male patients and was a prognostic marker, which may be associated, at least in part, with poorer prognosis in male patients with pulmonary hypertension.

Early Hemodynamic Profile after Aortic Valve Replacement — A Comparison between Three Mechanical Valves

IntroductionThere are scarce data comparing different mechanical valves in the aortic position. The objective of this study was to compare the early hemodynamic changes after aortic valve replacement between ATS, Bicarbon, and On-X mechanical valves.MethodsWe included 99 patients who underwent aortic valve replacement with mechanical valves between 2017 and 2019. Three types of mechanical valves were used, On-X valve (n=45), ATS AP360 (n=32), and Bicarbon (n=22). The mean prosthetic valve gradient was measured postoperatively and after six months.ResultsPreoperative data were comparable between groups, and there were no differences in preoperative echocardiographic data. Pre-discharge echocardiography showed no difference between groups in the ejection fraction (P=0.748), end-systolic (P=0.764) and end-diastolic (P=0.723) diameters, left ventricular mass index (P=0.348), aortic prosthetic mean pressure gradient (P=0.454), and indexed aortic prosthetic orifice area (P=0.576). There was no difference in the postoperative aortic prosthetic mean pressure gradient between groups when stratified by valve size. The changes in the aortic prosthetic mean pressure gradient of the intraoperative period, at pre-discharge, and at six months were comparable between the three prostheses (P=0.08). Multivariable regression analysis revealed that female gender (beta coefficient -0.242, P=0.027), body surface area (beta coefficient 0.334, P<0.001), and aortic prosthetic size (beta coefficient -0.547, P<0.001), but not the prosthesis type, were independent predictors of postoperative aortic prosthetic mean pressure gradient.ConclusionThe three bileaflet mechanical aortic prostheses (On-X, Bicarbon, and ATS) provide satisfactory early hemodynamics, which are comparable between the three valve types and among different valve sizes.

CFD ANALYSIS ON THE SINGLE-PHASE FLOW ELECTRICAL SUBMERSIBLE PUMP PERFORMANCE CURVE

Most of the industrial fields, especially oil and gas, involve the application of electrical submersible pump (ESP) for flow transport. The pump performance will deteriorate depending on conditions of usage. The main parameters that affect or influence the pump performance curve are pump types, fluid flow rates, gas fractions, the impellers’ geometry, rotational speeds and fluid properties. In this work, the pump performance curve was studied as the governing parameters such as flow rates, meshing elements and turbulence models were varied. A computational fluid dynamics simulation (CFD) was applied and the findings were compared with the manufacturer’s data for single-phase flows. The main purpose was focused on getting the right technique to investigate this problem. The various turbulence CFD models were analysed and sources of errors were explained. The corresponding pump head losses were discussed and the main improvement or the criteria to obtain the highest efficiency were suggested. The results show that the k-epsilon with enhanced wall treatment is the best CFD technique since it produces the most accurate results and the least errors by allowing flexibility in large pressure gradient and rapid changes in flow properties.Keywords: ESP, CFD simulation, head loss, performance curve, turbulence models

Study on Improving Cavitation Performance of Centrifugal Pump by Perforation at the Front Cover Plate

To improve the cavitation performance of a centrifugal pump, the high-pressure liquid in the front pump cavity is introduced into the cavitation area on the back of the blade by perforated holes at the front cover of the impeller. Based on the RNG k-ε turbulence model and Zwart-Gerber-be1amri cavitation model, the numerical calculation and analysis of the cavitation flow field in the model before and after perforation under different cavitation numbers is carried out by FLUENT. The results show that: The perforation at the front cover plate can effectively improve the pressure value of the cavitation area on the back of the blade. To some extent, the change of pressure gradient restrains the development of cavitation. The perforation at the front cover plate can effectively reduce the integral value of the cavitation bubble in the passage, improve the flow passage conditions in the impeller passage, and reduce the blockage degree of the cavitation to the passage. At the same time, the fluctuation range of the cavitation volume in the impeller is small in a rotation cycle after the perforation. It can be seen that the way of perforation at the front cover plate can effectively improve the cavitation performance of the centrifugal pump.

Effect of Endovascular Treatment on Systemic Vascular Resistance in Patients with Lower-Limb Peripheral Artery Disease.

Objective: Endovascular treatment (EVT) for lower-limb peripheral artery disease patients reduces blood pressure (BP) and improves prognosis. This study retrospectively examined hemodynamics during EVT to clarify the mechanism.Materials and Methods: Systemic vascular resistance (SVR) was measured using a noninvasive continuous cardiac output monitoring system during EVT. Furthermore, ankle brachial index was measured before and after EVT.Results: The study included 88 lesions of 56 patients (hypertension in 98%). SVR significantly decreased from 2409.1±746.8 dynes·s·cm−5 to 2033.7±635.0 dynes·s·cm−5 (p<0.0001). The difference in SVR before and after EVT was significantly greater in the Fontaine IV group than in the Fontaine IIa group (554.7±406.6 dynes·s·cm−5 vs. 312.9±245.7 dynes·s·cm−5, p=0.0151). The change in SVR was correlated with a change in mean BP in the upper limb (p=0.0026). When the change in pressure gradient between the upper limb and the diseased lower limb was large, mean BP of the upper limb significantly decreased (p=0.0022).Conclusion: EVT can reduce SVR and BP by canceling the pressure gradient between central BP and diseased lower-limb BP.

Pressure impact characteristic of vane type continuous rotary motor under different buffer structures

In order to solve the problem of pressure shock on the continuous rotary electro-hydraulic servo motor, the mathematical models of pressure gradient under the structure of pre-compressed chamber and U-shaped groove were established. The optimal structure dimensions of the pre-compressed chamber and the U-shaped groove were determined. The fluid models were established by Solidworks under the four structures of triangular groove, triangular groove with pre-compression chamber, U-shaped groove and U-shaped groove with pre-compression chamber. Simulation analysis of depressurization process of fluid models was performed based on FLUENT. The pressure nephograms of different buffer structures were compared and analyzed, and the pressure change curves and pressure gradient change curves in the process of depressurization were obtained. The results show that the optimal edge length of the pre-compressed chamber of continuous rotary electro-hydraulic servo motor is 20 mm in the process of decompression. The pressure reduction effect is the best when the width of the U-shaped groove is 1.5 mm and the depth is 1.65 mm. The U-shaped groove structure with pre-compression chamber is more conducive to alleviate the pressure shock phenomenon of the motor compared with different combine buffer structures.

Body-generated hydrodynamic flows influence male–male contests and female mate choice in a freshwater fish

The lateral line system of fishes is composed of neuromast mechanoreceptors that detect movement through vibration and changes in pressure gradients in the water. Although mechanosensory information has been shown to be important in the contexts of predator escape and foraging, little is known about the role of the lateral line system during intraspecific interactions, such as reproduction. However, many species of fish demonstrate complex courtship and aggressive repertoires that involve movement of the body and fins, resulting in local displacement of the surrounding water. This displacement has the potential to function as a signal that contains information about the sender. In this study, we conducted two behavioural experiments using fathead minnows, Pimephales promelas, to test the hypothesis that the outcomes of male–male contests and male–female courtship interactions are influenced by hydrodynamic flows generated during conspecific interactions. In the first experiment, we pitted control males against those with an ablated lateral line system and assessed both overall aggression and the likelihood of territory acquisition. In the second experiment, we conducted dual-choice female mate choice experiments to determine whether control females and those without access to mechanosensory information (ablated females) differed in patterns of discrimination and the use of courtship as a criterion of choice. In experiment 1, control males won a significantly greater proportion of territorial contests than expected by chance and were more likely to use noncontact threat displays during aggressive interactions compared with ablated males. In experiment 2, females with access to the mechanosensory information channel showed enhanced mate discrimination compared to ablated females. These data are among the first to show that mechanosensory signals are an important criterion of territorial and reproductive success in fishes and are likely important contributors to multimodal communication in this group.

The Effects of Canopy Morphology on Flow Over a Two‐Dimensional Isolated Ridge

AbstractMomentum and mass exchanges between the atmosphere and forests situated on complex terrain continue to draw significant research attention primarily because of their significance to a plethora of applications. In this paper, we investigated flows behavior on the leeward side of a two‐dimensional forested ridge under neutrally stratified conditions using large‐eddy simulations (LESs). The goal is to understand how variations in leaf area index (LAI), vertical canopy foliage distributions, and forest edge positions affect mean/turbulent flow statistics, momentum fluxes, and onset of recirculation patterns. Although pressure perturbations are dominated by the hill shape, it is demonstrated here that changes in canopy foliage distribution modulate intensities and patterns of the leeward adverse pressure gradients. Such changes in the adverse pressure gradients alter the mean velocity streamlines including the patterns and magnitudes of the leeward downward mean vertical velocity and the velocity variances and momentum flux in the wake region. While a downwind recirculation zone develops in all cases, the details regarding the incipient location and recirculation zone size vary including positions of the separation and reattachment points. Furthermore, changes in the strength and depth of the zone occur due to canopy‐induced changes in adverse pressure gradients, advection, and canopy drag. Because the recirculation zone impacts the local mean advective terms in momentum and scalar exchanges, the simulations here indicate that canopy morphology‐induced changes in the leeward flows have significant implications to both measurements and models of biosphere‐atmosphere exchange over complex terrain.

Mechanism of the Gas-Liquid Two-Phase Chaotic Flow in Single Fracture

The seepage of gas-liquid two-phase flow in fracture is a commonly found phenomenon in nature. To reveal the underlying mechanism and the critical condition of the chaos occurrence, a stochastic gas-liquid two-phase flow seepage model is established, and then investigated through a numerical simulation and a horizontal Hele-Shaw experiment. The numerical simulation and laboratory experiment results show that the seepage chaos of gas-liquid two-phase flow takes place when the relative saturation is in the range of gas relative saturation 44%-70%, and the occurrence probability can be expressed in polynomials. The chaos probability exceeds 80% when the relative saturation of gas is 47%-65%, and the chaos probability is 100% when the relative gas saturation is 57%-60%. It is found that the stochastic variation of gas connection cluster and the compressibility of gas lead to a remarkable change of pressure gradient of the gas-liquid flow both in magnitude and direction. Therefore, the turbulent flow is formed, the kinetic energy of fluid transport decreases gradually, and the flow is stopped at last.

The Effect of Longitudinal Pressure Gradient on Heat Transfer in a Separated Flow Behind a Sudden Expansion of the Channel

The results of an experimental study of the influence of longitudinal positive and negative pressure gradients in a rectangular flat channel with a backward-facing step on turbulent heat transfer in the zones of separation, attachment, and relaxation of the flow are presented. The studies were carried out in a turbulent flow regime at Reynolds numbers 4 × 103–1.2 × 104. The height of the step was equal to the half height of the channel before separation, so that the degree of its expansion was 1.5. The angle of diffuser opening varied from 0° to 4°, and confuser contraction ranged from 0° to 7.5°. The pressure fields and heat transfer coefficients in the recirculation and relaxation regions of the flow behind a sudden expansion of the channel were measured as a part of the experimental study. It is shown that with a change in the longitudinal pressure gradient, the behavior of the separated flow behind the step changes significantly. It has been determined that for a convergent channel with an increase in the pressure gradient, the maximum value of the Nusselt number increases, while for the expanding channel it decreases. The maximum Nusselt number position shifts downstream with diffuser expansion and approaches a step in the confusion flow.

Validation of four-dimensional flow cardiovascular magnetic resonance for aortic stenosis assessment

The management of patients with aortic stenosis (AS) crucially depends on accurate diagnosis. The main aim of this study were to validate the four-dimensional flow (4D flow) cardiovascular magnetic resonance (CMR) methods for AS assessment. Eighteen patients with clinically severe AS were recruited. All patients had pre-valve intervention 6MWT, echocardiography and CMR with 4D flow. Of these, ten patients had a surgical valve replacement, and eight patients had successful transcatheter aortic valve implantation (TAVI). TAVI patients had invasive pressure gradient assessments. A repeat assessment was performed at 3–4 months to assess the remodelling response. The peak pressure gradient by 4D flow was comparable to an invasive pressure gradient (54 ± 26 mmHG vs 50 ± 34 mmHg, P = 0.67). However, Doppler yielded significantly higher pressure gradient compared to invasive assessment (61 ± 32 mmHG vs 50 ± 34 mmHg, P = 0.0002). 6MWT was associated with 4D flow CMR derived pressure gradient (r = −0.45, P = 0.01) and EOA (r = 0.54, P < 0.01) but only with Doppler EOA (r = 0.45, P = 0.01). Left ventricular mass regression was better associated with 4D flow derived pressure gradient change (r = 0.64, P = 0.04). 4D flow CMR offers an alternative method for non-invasive assessment of AS. In addition, 4D flow derived valve metrics have a superior association to prognostically relevant 6MWT and LV mass regression than echocardiography.

Evaporation Kinetics of Nano Water Droplets using Coarse-Grained Molecular Dynamic Simulations

The utilization of nanocompounds can significantly enhance the production efficiency for solar steam generation, and much research and development efforts have been dedicated to designing their surface and structure to optimize the solar-heat conversion as well as evaporation performance. In particular, computational modeling studies using molecular dynamic (MD) simulations had been extensively performed for this objective. However, those studies typically assumed constant vacuum evaporation, thus yielding unrealistically high evaporation fluxes compared to laboratory and field measurements reported in the literature. To address this issue, we capture the transient thermodynamic properties of a nano water droplet that undergoes evaporation in a vapor medium under a closed periodic system with vapor pressures, using non-equilibrium MD simulations with the ELBA coarse-grain model. The changes of the nanodroplet and the localized vapor pressures inside the system from vacuum to saturation are monitored quantitatively. In addition, the varying radial extent of the Knudsen layer around the droplet is determined spatially through the transient pressure and energy distribution. The results illustrate the dynamical changes in the evaporation behavior from the diffusive-dominant to the kinetically limited transport mechanism. They also explain why the Kelvin equation can still apply in nanometer-scale systems, due to the fact that the density profiles are independent of the changes in pressure gradients. The Hertz-Knudsen Schrage equation, which is commonly used to compute the evaporation flux in the literature, is found unable to accurately predict the transient evaporative behavior observed. Thus, the results from this study illustrate that future molecular dynamic evaporation studies need to identify the location of the Knudsen layer in the simulations when calculating bulk evaporation fluxes in realistic vapor ambient conditions, due to its predominance in nanoscale interfacial processes.

Quantification of seasonal and diurnal dynamics of subglacial channels using seismic observations on an Alpine glacier

Abstract. Water flowing below glaciers exerts a major control on glacier basal sliding. However, our knowledge of the physics of subglacial hydrology and its link with sliding is limited because of lacking observations. Here we use a 2-year-long dataset made of on-ice-measured seismic and in situ-measured glacier basal sliding speed on Glacier d'Argentière (French Alps) to investigate the physics of subglacial channels and its potential link with glacier basal sliding. Using dedicated theory and concomitant measurements of water discharge, we quantify temporal changes in channels' hydraulic radius and hydraulic pressure gradient. At seasonal timescales we find that hydraulic radius and hydraulic pressure gradient respectively exhibit a 2- and 6-fold increase from spring to summer, followed by comparable decrease towards autumn. At low discharge during the early and late melt season channels respond to changes in discharge mainly through changes in hydraulic radius, a regime that is consistent with predictions of channels' behaviour at equilibrium. In contrast, at high discharge and high short-term water-supply variability (summertime), channels undergo strong changes in hydraulic pressure gradient, a behaviour that is consistent with channels behaving out of equilibrium. This out-of-equilibrium regime is further supported by observations at the diurnal scale, which prove that channels pressurize in the morning and depressurize in the afternoon. During summer we also observe high and sustained basal sliding speed, which supports that the widespread inefficient drainage system (cavities) is likely pressurized concomitantly with the channel system. We propose that pressurized channels help sustain high pressure in cavities (and therefore high glacier sliding speed) through an efficient hydraulic connection between the two systems. The present findings provide an essential basis for testing the physics represented in subglacial hydrology and glacier sliding models.

The time course of calf muscle fluid volume during prolonged running.

Muscle fluid is essential for the biochemistry and the biomechanics of muscle contraction. Here, we provide evidence that muscle fluid volumes undergo significant changes during 75 min of moderate intensity (2.7 ± 0.4 m/s) running. Using MRI measurements at baseline and after 2.5, 5, 10, 15, 45 and 75 min, we found that the volumes of calf muscles (quantified through average cross‐sectional area) in 18 young recreational runners increase (up to 9% in the gastrocnemii) at the beginning and decrease (below baseline levels) at later stages of running. However, the intensity of changes varied between analyzed muscles. We speculate that these changes are induced by muscle activity and dehydration‐related changes in osmotic pressure gradients between intramuscular and extramuscular spaces. These findings highlight the complex nature of muscle fluid shifts during prolonged running exercise.

On the Transition Between the Inner and Outer Plasma Sheet in the Earth's Magnetotail

AbstractWe have statistically studied the average structure and properties of the plasma sheet in the Earth's magnetotail at radial distances between R∼8 and 32 RE on the basis of ion, electron, and magnetic field data from the Geotail spacecraft. Here we discuss the transition between the inner plasma sheet and the outer plasma sheet near the equatorial plane. The ion and electron number densities, pressures, and energy fluxes at high energies, as well as the magnetic field, generally decrease with increasing radial distance from the Earth. The characteristics of the flux changes are reflected in the radial pressure gradients. If the transition between the inner and outer plasma sheet is determined by the radial pressure gradient change, the ion and electron transitions are located, on average, at R∼11 to 13 RE and R∼11 to 17 RE, respectively, at the midnight meridian. It is possible that the ion transition is located earthward of the electron transition. Furthermore, we have estimated the electric field, the electric and diamagnetic drift velocities, and the κ parameter (the square root of the ratio of the minimum curvature radius of the magnetic field line to the maximum gyroradius), which differ between the ion inner and outer plasma sheet.

Two-phase flow simulations at [formula omitted] inclination in an eccentric annulus

Co-current two-phase simulations of gas-liquid flow with mixture velocities from 1.2 to 4.2 m/s were run in a partially eccentric annulus and compared with entirely eccentric and concentric experimental data collected at the Institute for Energy Technology in Norway. The gas-phase was sulphur hexafluoride (SF6) for all cases, while the liquid-phase was Exxsol D60 for the horizontal cases and a mixture of Exxsol D60 and Marcol 82 for the inclined case. The outer diameter of the annulus was 0.1 m for all cases, while the inner diameter was 0.05 m in the horizontal configuration and 0.04 m for the inclined configuration. The purpose of this paper is to explore the effect of the holdup fraction, mixture velocity, and interior pipe’s position on the pressure gradient and flow regime, in effect a study of the pressure gradient and holdup fraction transients. The comparisons between simulations and experiments indicate that moving the pipe from an entirely eccentric to the partially eccentric configuration has a drastic impact on the pressure gradient. In all 4 cases where the inner pipe was changed from a completely eccentric geometry in the experiments to a less eccentric configuration in the simulations, we notice an increase of 48–303% of the mean pressure gradient. Comparatively, the 4 cases where the pipe was moved from a concentric experimental configuration to a more eccentric configuration in the simulations result in less drastic pressure gradient changes. Two cases were within 22% of the experimental results for mean, maximum, and minimum pressure gradient, while the last two cases exceeded the minimum and mean pressure gradients by 25–250%, respectively. The flow regime is rarely significantly affected by a change in eccentricity; 2 out of the 8 horizontal cases indicate either a transition from wavy flow to slug flow or significantly larger waves. The most prominent and frequent discrepancies identified were altered slug and wave frequencies. The last case, a 4o inclined, partially eccentric simulation was compared to an entirely eccentric experiment and results in a 0.2 Hz increase in wave frequency, up from the experimental 0.56 Hz and a 49% increase in the mean pressure gradient.

General Anesthesia Alters Intracranial Venous Pressures During Transverse Sinus Stenting

Pressure gradients across venous stenosis are used as a marker for physiologically significant narrowing in idiopathic intracranial hypertension. Performing such measurements under conscious sedation (CS) more likely reflects physiologic conditions, but can be uncomfortable, leading some operators to perform measurement under general anesthesia (GA), though this may not be equivalent. We performed a retrospective analysis of patients who received endovascular transverse sinus stenting due to idiopathic intracranial hypertension between August 2013 and May 2017. Patients' demographics and anesthetic parameters were collected along with venous pressure measurements. We identified 15 patients (14 women). The mean (SD) age was 30.5 (9.0) years and the mean body mass index (SD) was 39.5 (9.6) kg/m2. After measurements during CS, GA was induced with propofol and maintained with a volatile anesthetic. The median [IQR; range] transverse sinus pressure gradient under CS was 18 [12, 25; 6-38] mmHg compared with 14 [8, 21; 3-26] mm Hg under GA. The median [IQR; range] pressure gradient change after initiation of GA was -3 [-12, 0; -22 to 9] mm Hg (P= 0.014). After correction for increases in internal jugular vein pressures associated with assumption of GA, the median [IQR; range] gradient change was -11 [-12.5, -5; -22 to 0] mm Hg (P < 0.001). The transition from CS to GA results in clinically meaningful reductions in transverse sinus gradients in idiopathic intracranial hypertension. Correction for increases in the internal jugular vein pressures reveals even more dramatic reductions in transverse sinus gradients.

Tricuspid regurgitation pressure gradient identifies prognostically relevant worsening renal function in acute heart failure.

Not all worsening renal function (WRF) during heart failure treatment is associated with a poor prognosis. However, a metric capable providing a prognosis of relevant WRF has not been developed. Our aim was to evaluate if a change in tricuspid regurgitation pressure gradient (TRPG) could discriminate prognostically relevant and not relevant WRF in patients with acute heart failure (AHF). We examined 809 consecutive hospitalized patients with heart failure (78 ± 12 years, 54% male). WRF was defined as an increase in creatinine >0.3 mg and ≥25% from admission to discharge. TRPG was measured at admission and before discharge using echocardiography. The primary outcome was all-cause death within 1-year after discharge. Patients were classified as follows for analysis: no WRF and no TRPG increase (n = 523); no WRF and TRPG increase (no WRF with iTRPG, n = 170); WRF and no TRPG increase (WRF without iTRPG, n = 90); and WRF and TRPG increase (WRF with iTRPG, n = 26). A change in TRPG weakly but significantly correlated to a change in haemoglobin and haematocrit, a percent decrease in brain natriuretic peptide, and body weight reduction during the index period of hospitalization. All-cause mortality within 1 year was higher in patients with WRF and iTRPG, compared to the other three groups (P = 0.026). On Cox regression analysis, only WRF with iTRPG was associated with higher mortality (hazard ratio 4.24, P = 0.001), even after adjustment for other confounders. An increase in TRPG may provide a marker to identify prognostically relevant WRF in patients with AHF.