Concordance between venous sinus pressure and intracranial pressure in patients investigated for idiopathic intracranial hypertension.

BACKGROUND: Idiopathic intracranial hypertension (IIH) is a cause of chronic headaches that are probably driven by raised intracranial pressure (ICP). Cerebral venous sinus pressure is thought to play a role in the underlying pathology, but its relation with intracranial pressure requires further investigation. We aimed to evaluate the concordance between lumbar puncture opening pressure (LPOP) as indicator of the ICP and cerebral venous sinus pressure in patients investigated for IIH. METHODS: In this case-series replication study, all patients with IIH suspicion and who underwent cerebral venous sinus pressure measurement followed immediately by LP opening pressure (LPOP) measurement were retrospectively included. Pearson's correlation and measurement agreement (Bland-Altman plots) between venous pressure and LPOP were analyzed. RESULTS: 52 consecutive patients (46 women; median age, 31 years [IQR = 25-42]) were included. The mean pressure in the superior sagittal sinus (SSS) and in the torcular were 20.9mmHg (SD ± 7.3) and 20.8 mmHg (SD ± 6.8), respectively. The mean LPOP was 22mmHg (SD ± 6.4). Pressure measured in the transverse venous sinus, the torcular, and the SSS correlated with LPOP (p < 0.001). Bland-Altman plots showed that torcular pressure strongly agreed with LPOP (mean difference of 1.7mmHg). The limit of agreement (LOA) (mean difference ± 1.96SD) contained 98.1% of the differences between the two methods, confirming the concordance between the two measures. Torcular pressure and LPOP were consistent in patients with a trans-stenotic pressure gradient ≥ or < to 8 mmHg (mean difference: 1mmHg and 2.4mmHg, respectively), and for those with a LP OP ≥ or < to 18mmHg (mean difference: 1.8mmHg and 1.95mmHg, respectively). CONCLUSIONS: In patients investigated for IIH, the ICP measured at the LP is correlated and concordant with the torcular pressure. These results confirm previous findings and further corroborate the hypothesis that cerebral venous system plays a major role in CSF dynamics and ICP.

Monitoring the venous circulation: novel techniques and applications.

PURPOSE OF REVIEW: Venous pressure is an often-unrecognized cause of patient morbidity. However, bedside assessment of PV is challenging. We review the clinical significance of venous pressure measurement, existing techniques, and introduce the Venous Excess Ultrasound (VExUS) Score as a novel approach using doppler ultrasound to assess venous pressure. RECENT FINDINGS: Studies show clear associations between elevated venous pressure and adverse outcomes in critically ill patients. Current venous pressure measurement techniques include physical examination, right heart catheterization (RHC), two-dimensional ultrasound, and a variety of labor-intensive research-focused physiological maneuvers. Each of these techniques have specific shortcomings, limiting their clinical utility. To address these gaps, Beaubien-Souligny et al. introduced the VExUS Score, a novel doppler ultrasound-based method that integrates IVC diameter with doppler measurements of the hepatic, portal, and renal veins to generate a venous congestion assesment. Studies show strong correlations between VExUS score and RHC measurements, and well as an association between VExUS score and improvement in cardiorenal acute kidney injury, diuretic response, and fluid status shifts. However, studies in noncardiac populations have been small, heterogenous, and inconclusive. SUMMARY: Early studies evaluating the use of doppler ultrasound to assess venous congestion show promise, but further research is needed in diverse patient populations and clinical settings.

The retinal venous pressure at different levels of airway pressure measured with a new method.

PURPOSE: This study is to investigate the increase in retinal venous pressure (RVP) induced by a stepwise increase in airway pressure (AirP) using the new IOPstim method, which is designed to artificially increase the intraocular pressure (IOP) and thus to stimulate vascular pulsation. METHODS: Twenty-eight healthy subjects were examined in the left eye. The RVP was measured at baseline and at four different levels of AirP (10, 20, 30, and 40 mmHg) using the new IOPstim method: a half balloon of 8 mm diameter is inflated laterally to the cornea under observation of the central retinal vein. As soon as the vein pulsates at a certain AirP level, the IOP is measured with a commercially available tonometer, which then corresponds to the RVP. RESULTS: Spontaneous venous pulsation was observed in all study participants. The mean RVP values at baseline and at the AirP levels of 10, 20, 30, and 40 mmHg were 17.6 ± 2.8 mmHg; 20.1 ± 3.0 mmHg; 22.1 ± 3.5 mmHg; 24.3 ± 3.7 mmHg, and 26.6 ± 4.2 mmHg, respectively. The mean RVP values of each AirP level were statistically significantly different from each other in pairwise comparison. In a linear mixed model, the effect of AirP on RVP was highly significant (p < 0.001). In the model, a 10-mmHg increase in AirP resulted in a linear increase in RVP of 2.2 mmHg. CONCLUSION: An increase in AirP was accompanied by a linear increase in RVP. The influence of AirP on RVP, and thus on retinal perfusion pressure during the Valsalva maneuver, is less than was assumed based on previous studies in which contact lens dynamometry was used.

Noninvasive measurement of ambulatory venous pressure via column interruption duration in chronic venous disease.

BACKGROUND: Column interruption duration (CID) is a noninvasive surrogate for venous refill time (VFT), a parameter used in ambulatory venous pressure measurement. CID is more accurate than invasive VFT measurement because it avoids errors involved with indirect access of the deep system through the dorsal foot vein. The aim of this retrospective single center study is to analyze the clinical usefulness of CID in assessment of chronic venous disease (CVD). METHODS: A total of 1551 limbs (777 patients) were referred with CVD symptoms over a 5-year period (2018-2023); CID, air plethysmography, and duplex reflux data were analyzed. Of these limbs, 679 had supine venous pressure data as well. The pathology was categorized as obstruction if supine peripheral venous pressure was >11 mm Hg and as reflux if duplex reflux time in superficial or deep veins was >1 second. CID was measured via Doppler monitoring of flow in the great saphenous vein (GSV) and one of the paired posterior tibial (PT) veins near the ankle in the erect posture. The calf is emptied by rapid inflation cuff. CID is the time interval in seconds when cephalad venous flow in great saphenous vein and posterior tibial veins reappear after calf ejection. A CID <20 seconds in either vein is abnormal similar to the threshold used in VFT measurement. RESULTS: Thirty-two percent of the limbs had obstruction, 17% had reflux, and 37% had a combination; 14% had neither. Higher clinical-etiology-anatomy-pathophysiology (CEAP) clinical classes (C4-6) were prevalent in 44% of pure reflux, significantly less (P < .0001) than in pure obstruction (73%) or obstruction plus reflux subsets (72%), partly reflecting distribution of pathology. There is a progressive increase in supine venous pressure and abnormal CID (P < .0001 and P < .0001, respectively) in successive CEAP clinical class. No such correlation between CEAP and any of the reflux severity grading methods (reflux segment score, Venous Filling Index, and Kistner axial grading) was observed. Abnormal CID (55%) was more prevalent in higher CEAP classes (>4) (P < .0001) than in lesser clinical classes (0-2) or limbs with neither obstruction nor reflux (P < .01). CONCLUSIONS: Obstruction seems to be a more dominant pathology in clinical progression among CEAP clinical classes than reflux. CID is abnormal in both obstructive and refluxive pathologies and may represent a common end pathway for similar clinical manifestations (eg, ulcer). These data suggest a useful role for CID measurement in clinical assessment of limbs with CVD.

Preliminary Study on the Correlation Between Episcleral Venous Pressure and Intraocular Pressure in TAO Patients and Its Clinical Value.

Objective: To study the correlation between episcleral vein pressure (EVP) with intraocular pressure (IOP), exophthalmos, and optic nerve injury in thyroid-associated ophthalmopathy (TAO) patients and to explore the possibility of higher EVP as an intervention indicator in TAO patients. Methods: This study was a case-control study, including the TAO group and normal control group. TAO group: 15 patients (30 eyes) were diagnosed with TAO complicated with exophthalmos. Normal control group: 14 cases, 28 eyes. EVP, IOP, exophthalmos, retinal nerve fiber layer thickness, and visual field were measured, respectively in the two groups. Non-parametric test was used to compare the difference between EVP and IOP between the two groups, test the correlation between EVP and IOP or exophthalmos, and analyze the clinical characteristics of optic nerve injury in patients with elevated IOP in the TAO group. Results: The EVP in the TAO group (15.30±3.48 mmHg) was significantly higher than the normal control group (8.82±1.44 mmHg) (P < .001). The IOP in the TAO group (18.55±8.13 mmHg) was significantly higher than in the normal control group (12.98±2.10 mmHg) (P < .001) (3) There was a positive linear correlation between EVP (X) and IOP (Y) in TAO group: Y = 0.9684x + 3.737 (rs>0, P < .05); There was a positive linear correlation between EVP (Y) and exophthalmos (X) in TAO group: Y = 0.9218x - 2.691 (rs>0, P < .05); Some TAO patients with elevated EVP had the related manifestations of optic nerve function impairment: thinning of retinal nerve fiber layer and loss of visual field. However, there was no clear correlation between EVP and the thickness of the optic nerve fiber layer (P = .4354). Conclusion: The increase of EVP is an important factor leading to elevated IOP in TAO patients, which may be used as an indicator for intervention treatment in TAO patients. EVP can be used to indirectly evaluate orbital pressure. TAO patients can develop secondary glaucoma with irreversible optic nerve damage due to the continuous Elevation of EVP.

[HVPG minimally invasive era: exploration based on forearm venous approach].

Objective: The transjugular or transfemoral approach is used as a common method for hepatic venous pressure gradient (HVPG) measurement in current practice. This study aims to confirm the safety and effectiveness of measuring HVPG via the forearm venous approach. Methods: Prospective recruitment was conducted for patients with cirrhosis who underwent HVPG measurement via the forearm venous approach at six hospitals in China and Japan from September 2020 to December 2020. Patients' clinical baseline information and HVPG measurement data were collected. The right median cubital vein or basilic vein approach for all enrolled patients was selected. The HVPG standard process was used to measure pressure. Research data were analyzed using SPSS 22.0 statistical software. Quantitative data were used to represent medians (interquartile ranges), while qualitative data were used to represent frequency and rates. The correlation between two sets of data was analyzed using Pearson correlation analysis. Results: A total of 43 cases were enrolled in this study. Of these, 41 (95.3%) successfully underwent HVPG measurement via the forearm venous approach. None of the patients had any serious complications. The median operation time for HVPG detection via forearm vein was 18.0 minutes (12.3~38.8 minutes). This study confirmed that HVPG was positively closely related to Child-Pugh score (r = 0.47, P = 0.002), albumin-bilirubin score (r = 0.37, P = 0.001), Lok index (r = 0.36, P = 0.02), liver stiffness (r = 0.58, P = 0.01), and spleen stiffness (r = 0.77, P = 0.01), while negatively correlated with albumin (r = -0.42, P = 0.006). Conclusion: The results of this multi-centre retrospective study suggest that HVPG measurement via the forearm venous approach is safe and feasible.

Low Mean Perfusion Pressure Indexed to Body Surface Area is a Powerful Predictor of Poor Outcomes After Heart Transplantation in Patients With High Pre-Transplant Venous Pressure: A Clinical Study With Physiological Insights From Mathematical Modelling of Biventricular Heart Failure.

BACKGROUND & AIM: The deleterious consequences of chronically elevated venous pressure in patients with profound right ventricular or biventricular dysfunction are well known, including renal and hepatic dysfunction, and volume overload. The only option for these patients, if they fail optimal medical treatment, is a heart transplant, as they are not candidates for left ventricular assist device therapy. Mean perfusion pressure (MPP) is important in the outcomes of critically ill patients with high venous pressure. The question arises whether MPP is important for the outcomes of heart transplants in patients with elevated pre-transplant venous pressure. Medical management of heart failure patients with reduced ejection fraction involves lowering the systemic afterload with vasodilators while awaiting a transplant. We hypothesised that when venous pressure is elevated prior to transplant, a substantial reduction in systemic arterial elastance (Ea) through vasodilation may significantly decrease MPP, resulting in compromised end-organ function and consequent unfavourable outcomes after heart transplantation. This study aims to investigate whether a low MPP serves as a risk factor for adverse outcomes in heart transplant recipients with high venous pressure. METHOD: A retrospective analysis was conducted on 250 heart transplant recipients undergoing isolated heart transplantation at a single institution from October 2012 to March 2020. Right atrial pressure (RAP) of more than 15 mmHg was considered high. Additionally, Ea calculated as the ratio of end-systolic pressure to stroke volume, and MPP calculated as the difference between mean arterial pressure and RAP were considered in our analysis. The outcomes of transplantation were measured in terms of 90-day mortality and survival up to 7 years. RESULTS: High RAP was a significant risk factor for short-term and medium-term survival if Ea was low (<2.7 mmHg/mL, the median value). This group had 39.39% in-hospital mortality compared to 14.49% for RAP<15 mmHg (p∼0.005). When Ea was high, this difference in survival was not evident: 8% for RAP<15 mmHg vs 4.8% for RAP>15 mmHg (p∼0.550). This effect was mediated through a lower MPP, and the mortality due to lower MPP increased strikingly with higher body surface area (BSA). A negative correlation was observed between MPP indexed to BSA (MPPI) and the Model for End-Stage Liver Disease score (r∼-0.3580, p<0.0001) as well as creatinine (r∼-0.3551, p<0.0001). MPPI less than 40 mmHg/m2 was associated with poorer short-term (23.2% for MPPI<40 mmHg/m2 vs 7.1% for MPPI>40 mmHg/m2, p∼0.001) and medium-term survival. The impact of high RAP and low Ea on survival was evident even on medium-term follow-up; only 30% survival at 7 years follow-up for high RAP and low Ea vs 75% for RAP<15 mmHg (p∼0.0033). CONCLUSION: The acceptable blood pressure during vasodilator therapy in patients with high RAP needs to be higher, especially in those with higher BSA. MPPI less than 40 mmHg/m2 is a risk factor for survival, in the short and medium-term, after heart transplantation.

Measurement of the retinal venous pressure with a new instrument in patients with primary open angle glaucoma.

PURPOSE: To compare the results of retinal venous pressure (RVP) measurement performed with contact lens dynamometry (CLD) and with the new IOPstim. METHODS: In this cross-sectional study, we included 36 patients with primary open angle glaucoma with a median age (Q25; Q75) of 74 (64; 77) years (m/f = 18/18), baseline intraocular pressure (IOP): 13.9 (12.2; 15.1) mmHg. Median mean defect: - 5.8 (- 11.9; - 2.6) db. Principle of the IOPstim: an empty balloon with a diameter of 8 mm is positioned on the eye, laterally of the limbus. Under observation of the central retinal vein (CRV), the examiner inflates the balloon. As soon as the CRV starts pulsation, the inflation is stopped and the IOP is measured, equaling the RVP at this moment. In the CLD, the pulsation of the CRV is observed with a contact lens. The RVP is calculated from the attachment force applied when pulsation appears. COURSE OF EXAMINATIONS: Three single measurements of RVP in quick succession with both methods. The sequence of the two methods was randomized. The means of the three RVP measurements were compared. RESULTS: Pressures in mmHg. RVP: IOPstim: 19.4 ± 5.4 (mean ± SD), CLD: 20.3 ± 5.9. Range of three single measurements: IOPstim: 2.9 ± 1.5, CLD: 2.2 ± 1.1. The differences were RVPIOPstim - RVPCLD = - 0.94 ± 1.15, and approximately normally distributed. Bland-Altman analysis: only one data point was 0.5 mmHg higher than the upper line of agreement. The confidence interval of this line was 0.65 mmHg. Concordance correlation coefficient according to Lin (CCC): 0.96. Intraclass correlation coefficient: both methods, 0.94. CONCLUSION: In both methods, the range of the single measurements may be taken as a sign of good reliability, the CCC of 0.96 as a sign of a very good agreement. At the mean, the IOPstim RVP values were 1 mmHg lower than those obtained with the CLD. This difference may be due to the different directions of the prevailing force vectors induced by the instruments. The IOPstim seems applicable in glaucoma diagnostics.

Prognostic performance of non-invasive tests for portal hypertension is comparable to that of hepatic venous pressure gradient.

BACKGROUND & AIMS: Non-invasive tests to assess the probability of clinically significant portal hypertension (CSPH) - including the ANTICIPATE±NASH models based on liver stiffness measurement and platelet count±BMI, and the von Willebrand factor antigen to platelet count ratio (VITRO) - have fundamentally changed the management of compensated advanced chronic liver disease (cACLD). However, their prognostic utility has not been compared head-to-head to the gold standard for prognostication in cACLD, i.e. the hepatic venous pressure gradient (HVPG). METHODS: Patients with cACLD (liver stiffness measurement ≥10 kPa) who underwent advanced characterization via same-day HVPG/non-invasive test assessment from 2007-2022 were retrospectively included. Long-term follow-up data on hepatic decompensation was recorded. RESULTS: Four hundred and twenty patients with cACLD of varying etiologies, with a CSPH prevalence of 67.6%, were included. The cumulative incidence of hepatic decompensation at 1 and 2 years was 4.7% and 8.0%, respectively. HVPG, VITRO, and ANTICIPATE±NASH-CSPH-probability showed similar time-dependent prognostic value (AUROCs 0.683-0.811 at 1 year and 0.699-0.801 at 2 years). In competing risk analyses adjusted for MELD score and albumin, HVPG (adjusted subdistribution hazard ratio [aSHR] 1.099 [95% CI 1.054-1.150] per mmHg; p <0.001), or VITRO (aSHR 1.134 [95% CI 1.062-1.211] per unit; p <0.001), or ANTICIPATE±NASH-CSPH-probability (aSHR 1.232 [95% CI 1.094-1.387] per 10%; p <0.001) all predicted first decompensation during follow-up. Previously proposed cut-offs (HVPG ≥10 mmHg vs. <10 mmHg, VITRO ≥2.5 vs. <2.5, and ANTICIPATE-CSPH probability ≥60% vs. <60%) all accurately discriminated between patients at negligible risk and those at substantial risk of hepatic decompensation. CONCLUSIONS: The prognostic performance of ANTICIPATE±NASH-CSPH-probability and VITRO is comparable to that of HVPG, supporting their utility for identifying patients who may benefit from medical therapies to prevent first hepatic decompensation. IMPACT AND IMPLICATIONS: Non-invasive tests have revolutionized the diagnosis and management of clinically significant portal hypertension in patients with compensated advanced chronic liver disease (cACLD). However, limited data exists regarding the prognostic utility of non-invasive tests in direct comparison to the gold standard for prognostication in cACLD, i.e. the hepatic venous pressure gradient. In our study including 420 patients with cACLD, the ANTICIPATE±NASH model and VITRO yielded similar AUROCs to hepatic venous pressure gradient for hepatic decompensation within 1 to 2 years. Thus, non-invasive tests should be applied and updated in yearly intervals in clinical routine to identify patients at short-term risk, thereby identifying patients who may benefit from treatment aimed at preventing hepatic decompensation.

Signal quality assessment of peripheral venous pressure.

Develop a signal quality index (SQI) for the widely available peripheral venous pressure waveform (PVP). We focus on the quality of the cardiac component in PVP. We model PVP by the adaptive non-harmonic model. When the cardiac component in PVP is stronger, the PVP is defined to have a higher quality. This signal quality is quantified by applying the synchrosqueezing transform to decompose the cardiac component out of PVP, and the SQI is defined as a value between 0 and 1. A database collected during the lower body negative pressure experiment is utilized to validate the developed SQI. All signals are labeled into categories of low and high qualities by experts. A support vector machine (SVM) learning model is trained for practical purpose. The developed signal quality index coincide with human experts' labels with the area under the curve 0.95. In a leave-one-subject-out cross validation (LOSOCV), the SQI achieves accuracy 0.89 and F1 0.88, which is consistently higher than other commonly used signal qualities, including entropy, power and mean venous pressure. The trained SVM model trained with SQI, entropy, power and mean venous pressure could achieve an accuracy 0.92 and F1 0.91 under LOSOCV. An exterior validation of SQI achieves accuracy 0.87 and F1 0.92; an exterior validation of the SVM model achieves accuracy 0.95 and F1 0.96. The developed SQI has a convincing potential to help identify high quality PVP segments for further hemodynamic study. This is the first work aiming to quantify the signal quality of the widely applied PVP waveform.

The influence of spinal venous blood pressure on cerebrospinal fluid pressure.

In Alligator mississippiensis the spinal dura is surrounded by a venous sinus; pressure waves can propagate in the spinal venous blood, and these spinal venous pressures can be transmitted to the spinal cerebrospinal fluid (CSF). This study was designed to explore pressure transfer between the spinal venous blood and the spinal CSF. At rest the cardiac-related CSF pulsations are attenuated and delayed, while the ventilatory-related pulsations are amplified as they move from the spinal venous blood to the spinal CSF. Orthostatic gradients resulted in significant alterations of both cardiac- and ventilatory-related CSF pulsations. Manual lateral oscillations of the alligator's tail created pressure waves in the spinal CSF that propagated, with slight attenuation but no delay, to the cranial CSF. Oscillatory pressure pulsations in the spinal CSF and venous blood had little influence on the underlying ventilatory pulsations, though the same oscillatory pulsations reduced the ventilatory- and increased the cardiac-related pulsations in the cranial CSF. In Alligator the spinal venous anatomy creates a more complex pressure relationship between the venous and CSF systems than has been described in humans.

Jugular Venous Pressure and Kussmaul's Sign as Predictors of Outcome in Heart Failure.

Simplifying the estimation of internal jugular venous pressure (JVP) as visible or not visible above the right clavicle in the sitting position has attracted attention for risk assessment in patients with heart failure (HF). It remains unclear whether this simple assessment, combined with its inspiration response known as Kussmaul's sign, is useful in patients with HF who vary in features such as HF with reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF).This study consisted of 246 patients who were admitted for the management of HF. JVP was assessed before discharge and considered high if visible at rest. The inspiration response was also examined. The primary outcome was a composite of all-cause death and hospitalization for worsening HF.One year after discharge, primary outcome events occurred in 91 patients (37%). The incidence of primary outcome was higher in patients with a high JVP at rest (odds ratio, 5.06; 95% confidence interval, 2.31-11.1; P = 0.0001) or with inspiration (odds ratio, 5.93; 95% confidence interval, 2.14-16.4; P < 0.01) than in patients without high JVP conditions. These findings were similarly observed among patients with HFrEF and HFpEF (odds ratios, 3.53 and 6.76; 95% confidence intervals, 1.68-8.68 and 2.19-15.5; P = 0.01 and < 0.01, respectively) and in subgroup analysis stratified by baseline characteristics of the patients.A high JVP at rest and with inspiration as assessed by this simple, practical method may be useful for risk assessment in patients with HF, independent of baseline characteristics.

Association Between the Liver Fibrosis Markers and Scores, and Hemodynamic Congestion Assessed by Peripheral Venous Pressure in Patients With Acute Heart Failure.

Background Peripheral venous pressure (PVP) has been shown to be a reliable surrogate for right atrial pressure in assessing congestion in patients with heart failure (HF). Liver fibrosis markers and scores can be useful in assessing organ injury in patients with acute HF. This study aimed to investigate the association of liver fibrosis markers and scores with PVP in patients with acute HF. Methods and Results The 7S domain of the collagen type IV N-terminal propeptide (P4NP 7S), aspartate aminotransferase-to-platelet ratio index, fibrosis-4, and nonalcoholic fatty liver disease fibrosis score were determined along with PVP measurements before discharge in 229 patients with acute HF. The strongest correlation with PVP was found for P4NP 7S (Pearson r=0.40). Patients with high P4NP 7S levels (≥median [6.2 ng/mL]) had an increased risk of cardiovascular death or HF hospitalization (adjusted hazard ratio [HR], 1.80 [95% CI, 1.09-3.04], P=0.02). The concomitant high PVP (≥mean [8 mm Hg])/high P4NP 7S group, in contrast to the high PVP/low P4NP 7S or low PVP/high P4NP 7S group, had a significant risk relative to the low PVP/low P4NP 7S group for cardiovascular death or HF hospitalization (adjusted HR, 2.63 [95% CI, 1.43-5.05], P=0.002). A sustained elevation in PVP for 1 month postdischarge was associated with a persistent increase in P4NP 7S. Conclusions The study demonstrated the relationship between the liver fibrosis marker P4NP 7S and congestion. PVP and P4NP 7S could be useful for assessing congestion-related organ injury and predicting prognosis in patients with acute HF.

Assessment of venous pressure by compression sonography of the internal jugular vein during 3 days of bed rest.

Compression sonography has been proposed as a method for non-invasive measurement of venous pressures during spaceflight, but initial reports of venous pressure measured by compression ultrasound conflict with prior reports of invasively measured central venous pressure (CVP). The aim of this study is to determine the agreement of compression sonography of the internal jugular vein (IJVP) with invasive measures of CVP over a range of pressures relevant to microgravity exposure. Ten healthy volunteers (18-55 years, five female) completed two 3-day sessions of supine bed rest to simulate microgravity. IJVP and CVP were measured in the seated position, and in the supine position throughout 3 days of bed rest. The range of CVP recorded was in line with previous reports of CVP during changes in posture on Earth and in microgravity. The correlation between IJVP and CVP was poor when measured during spontaneous breathing (r = 0.29; R2  = 0.09; P = 0.0002; standard error of the estimate (SEE) = 3.0 mmHg) or end-expiration CVP (CVPEE ; r = 0.19; R2  = 0.04; P = 0.121; SEE = 3.0 mmHg). There was a modest correlation between the change in CVP and the change in IJVP for both spontaneous ΔCVP (r = 0.49; R2  = 0.24; P < 0.0001) and ΔCVPEE (r = 0.58; R2  = 0.34; P < 0.0001). Bland-Altman analysis of IJVP revealed a large positive bias compared to spontaneous breathing CVP (3.6 mmHg; SD = 4.0; CV = 85%; P < 0.0001) and CVPEE (3.6 mmHg; SD = 4.2; CV = 84%; P < 0.0001). Assessment of absolute IJVP via compression sonography correlated poorly with direct measurements of CVP by invasive catheterization over a range of venous pressures that are physiologically relevant to spaceflight. However, compression sonography showed modest utility for tracking changes in venous pressure over time. NEW FINDINGS: What is the central question of this study? Compression sonography has been proposed as a novel method for non-invasive measurement of venous pressures during spaceflight. However, the accuracy has not yet been confirmed in the range of CVP experienced by astronauts during spaceflight. What is the main finding and its importance? Our data show that compression sonography of the internal jugular vein correlates poorly with direct measurement of central venous pressures in a range that is physiologically relevant to spaceflight. However, compression sonography showed modest utility for tracking changes in venous pressure over time.

Coronary Venous Pressure and Microvascular Hemodynamics in Patients With Microvascular Angina: A Randomized Clinical Trial.

Importance: The role of the coronary venous circulation in regulating myocardial perfusion and its potential in treating microvascular angina is unexplored. Objective: To evaluate whether an increase in coronary venous pressure modifies microvascular resistance in patients with microvascular angina. Design, Setting, and Participants: This was a blinded, sham-controlled, crossover, randomized clinical trial that enrolled participants between November 2021 and January 2023. Participants for this physiology end point study were recruited from the Cardiology Center of the University of Medicine in Mainz, Germany. Patients with moderate/severe angina pectoris (Canadian Cardiovascular Society class 2-4) due to microvascular dysfunction (as defined by the thermodilution-based index of microvascular resistance >25 mm Hg × s). Exclusion criteria were epicardial coronary disease, second- and third-degree atrioventricular block, severe valvular heart disease, cardiomyopathy, and pulmonary or kidney disease. Intervention: Inflation of an undersized balloon placed in the cardiac coronary sinus (CS), hereafter referred to as balloon and the deflated balloon in the right atrium, referred to as sham. Measurements were performed at rest and during maximal coronary hyperemia. Both patients and final assessors were blinded to the randomization sequence. Main Outcomes and Measures: Hemodynamic parameters, including aortic (Pa) and distal (Pd) coronary pressure, coronary sinus pressure (Pcs), right atrial pressure (Pra), and the mean transit time (inverse of blood flow [Tmn]), were measured. Results: A total of 20 patients (median [IQR] age, 69 [64-75] years; 11 female [55.0%]) were included in the study. Two patients (10%) had diabetes, 6 (30%) had hypercholesterolemia, 15 (75%) had hypertension, and 3 (15%) were active smokers. The inflation of the CS balloon caused a significant increase in CS pressure at rest and during hyperemia (300% and 317% increase, respectively, compared with sham, both P < .001), a decrease in hyperemic distal coronary pressure (median [IQR], sham: 92 [80-100] mm Hg; balloon: 79 [75-93] mm Hg; P = .01) and mean transit time (sham: 0.39 [0.23-0.62] s; balloon: 0.26 [0.17-0.46] s; P = .008). As a result, CS occlusion led to a decrease in both resting coronary resistance (median [IQR], sham: 59 [37-87] mm Hg × s; balloon: 42 [31-67] mm Hg × s; P = .005) and the primary end point hyperemic coronary resistance (mean [IQR], sham: 31 [23-53] mm Hg × s; balloon: 14 [8-26] mm Hg × s; P < .001). Conclusion and Relevance: Increased coronary venous pressure led to a reduction of microvascular resistances in patients with microvascular angina, a mechanism with potential implications for the therapy of this complex disease. Trial Registration: ClinicalTrials.gov Identifier: NCT05034224.

Non-invasive candidate protein signature predicts hepatic venous pressure gradient reduction in cirrhotic patients after sustained virologic response.

BACKGROUND AND AIMS: A reduction in hepatic venous pressure gradient (HVPG) is the most accurate marker for assessing the severity of portal hypertension and the effectiveness of intervention treatments. This study aimed to evaluate the prognostic potential of blood-based proteomic biomarkers in predicting HVPG response amongst cirrhotic patients with portal hypertension due to Hepatitis C virus (HCV) and had achieved sustained virologic response (SVR). METHODS: The study comprised 59 patients from two cohorts. Patients underwent paired HVPG (pretreatment and after SVR), liver stiffness (LSM), and enhanced liver fibrosis scores (ELF) measurements, as well as proteomics-based profiling on serum samples using SomaScan® at baseline (BL) and after SVR (EOS). Machine learning with feature selection (Caret, Random Forest and RPART) methods were performed to determine the proteins capable of classifying HVPG responders. Model performance was evaluated using AUROC (pROC R package). RESULTS: Patients were stratified by a change in HVPG (EOS vs. BL) into responders (greater than 20% decline in HVPG from BL, or <10 mmHg at EOS with >10 mmHg at BL) and non-responders. LSM and ELF decreased markedly after SVR but did not correlate with HVPG response. SomaScan (SomaLogic, Inc., Boulder, CO) analysis revealed a substantial shift in the peripheral proteome composition, reflected by 82 significantly differentially abundant proteins. Twelve proteins accurately distinguished responders from non-responders, with an AUROC of .86, sensitivity of 83%, specificity of 83%, accuracy of 83%, PPV of 83%, and NPV of 83%. CONCLUSIONS: A combined non-invasive soluble protein signature was identified, capable of accurately predicting HVPG response in HCV liver cirrhosis patients after achieving SVR.

Diagnostic accuracy of the peripheral venous pressure variation induced by an alveolar recruitment maneuver to predict fluid responsiveness during high-risk abdominal surgery.

BACKGROUND: In patients undergoing high-risk surgery, it is recommended to titrate fluid administration using stroke volume or a dynamic variable of fluid responsiveness (FR). However, this strategy usually requires the use of a hemodynamic monitor and/or an arterial catheter. Recently, it has been shown that variations of central venous pressure (ΔCVP) during an alveolar recruitment maneuver (ARM) can predict FR and that there is a correlation between CVP and peripheral venous pressure (PVP). This prospective study tested the hypothesis that variations of PVP (ΔPVP) induced by an ARM could predict FR. METHODS: We studied 60 consecutive patients scheduled for high-risk abdominal surgery, excluding those with preoperative cardiac arrhythmias or right ventricular dysfunction. All patients had a peripheral venous catheter, a central venous catheter and a radial arterial catheter linked to a pulse contour monitoring device. PVP was always measured via an 18-gauge catheter inserted at the antecubital fossa. Then an ARM consisting of a standardized gas insufflation to reach a plateau of 30 cmH2O for 30 s was performed before skin incision. Invasive mean arterial pressure (MAP), pulse pressure, heart rate, CVP, PVP, pulse pressure variation (PPV), and stroke volume index (SVI) were recorded before ARM (T1), at the end of ARM (T2), before volume expansion (T3), and one minute after volume expansion (T4). Receiver-operating curves (ROC) analysis with the corresponding grey zone approach were performed to assess the ability of ∆PVP (index test) to predict FR, defined as an ≥ 10% increase in SVI following the administration of a 4 ml/kg balanced crystalloid solution over 5 min. RESULTS: ∆PVP during ARM predicted FR with an area under the ROC curve of 0.76 (95%CI, 0.63 to 0.86). The optimal threshold determined by the Youden Index was a ∆PVP value of 5 mmHg (95%CI, 4 to 6) with a sensitivity of 66% (95%CI, 47 to 81) and a specificity of 82% (95%CI, 63 to 94). The AUC's for predicting FR were not different between ΔPVP, ΔCVP, and PPV. CONCLUSION: During high-risk abdominal surgery, ∆PVP induced by an ARM can moderately predict FR. Nevertheless, other hemodynamic variables did not perform better.