Venous Pressure Measurements Research Articles

A compact machine perfusion device for whole blood perfusion in isolated rat liver.

We established a compact machine perfusion system for whole blood perfusion of rat liver by making use of oxygenation filters as an artificial lung. Livers removed from rats were divided into Krebs-Henseleit (control), 50% blood (hemoglobin: 7g/dL), and whole blood (hemoglobin: 14g/dL) groups, then perfused (total perfusate volume: 25ml) with a small oxygenation filter at 37°C for 120min. Blood or perfusate was collected over time, and blood gas and blood cell were measured. In addition, bile volume and portal venous pressure measurements were taken. In all groups, the partial pressure of oxygen was controlled to approximately 400mmHg. Flow rates were maintained at approximately about 20-30ml/min according to liver size. Portal venous pressure was normal in the 50% blood and whole blood groups, while lower than the reference value in the Krebs-Henseleit group. Twice as much bile was produced in the 50% blood and whole blood groups relative with the Krebs-Henseleit group. We observed no differences in hemoglobin and red blood cell levels. Lactate levels were normal in the 50% blood and whole blood groups, but were elevated in the Krebs-Henseleit group. Our compact perfusion system using oxygenation filters was able to maintain rat liver function by perfusing a small amount of extracorporeal blood. This system is simple and stable, and may contribute to the future development of machine perfusion systems.

Assessment of superior vena cava diameter and collapsibility index in liver transplantation: a prospective observational study

BackgroundSuperior Vena Cava (SVC) diameter and collapsibility index, dynamic measures of fluid responsiveness, have been successfully utilized as echocardiographic indices for fluid responsiveness in ventilated septic patients. Whether these measurements are correlated with Central Venous Pressure (CVP) measurements in liver transplant patients is unknown. We sought to assess the correlation of maximum and minimum SVC diameter and SVC collapsibility index measurements obtained intraoperatively by Transesophageal Echocardiography (TEE) with those of simultaneously recorded CVP measurements obtained through a right atrial port of a pulmonary artery catheter. The secondary aim of the study was to assess the correlation between SVC measurements and simultaneously obtained thermodilution cardiac index measurements. MethodsSingle center prospective observational trial of patients with end stage liver disease undergoing liver transplantation in an academic tertiary care center. ResultsThe minimum SVC exhibited a mild significant correlation with CVP as did the maximum SVC. The correlation between the SVC collapsibility index and CVP was not significantly different from zero. In our secondary analysis, the correlation between minimum SVC diameter and cardiac index was determined to be weak but non-zero as was the correlation between the maximum SVC diameter and cardiac index. The correlation between SVC collapsibility index and cardiac index was not different from zero. ConclusionWhile statistically significant, the weak clinical correlation of intraoperative SVC measurements obtained by TEE make them unsuitable as a replacement for central venous pressure or thermodilution cardiac index measurements in liver transplant recipients.

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

BackgroundIdiopathic 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.MethodsIn 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.Results52 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).ConclusionsIn 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.

Elevated systemic venous pressures as a possible pathology in prepubertal pediatric idiopathic intracranial hypertension.

Pediatric idiopathic intracranial hypertension (IIH) is a rare and challenging condition. As implied by the nomenclature, the etiologies remain unknown, and multiple etiologies are being investigated. In this study, we explored the potential role of increased systemic or cerebral venous pressure in the pathogenesis. An observational cohort study following the STROBE guidelines, including prepubertal children with clinical symptoms and imaging findings consistent with IIH referred to the neurosurgical department, was conducted. The patients underwent a comprehensive diagnostic protocol, including MRI, continuous intracranial pressure (ICP) monitoring, and endovascular venography with venous pressure measurements. The study included 11 consecutive patients (six boys and five girls) with an average age of 2.3years, and an average BMI of 18.4. Among these, one patient was found to have venous stenosis with a gradient; the other 10 patients presented with normal intracranial anatomy. All patients exhibited elevated venous pressures, with an average superior sagittal sinus pressure of 18.9mmHg, average internal jugular vein pressure of 17.0mmHg, and average central venous pressure of 15.9mmHg. Daytime ICP averaged 12.9mmHg, whereas nighttime ICP averaged 17.2mmHg with either A- or B-waves in 10 of the 11 patients. Despite pathological ICP, only three patients had papilledema. All patients had an increased systemic venous pressure, indicating a possible pathological factor for prepubertal IIH. Additionally, our findings show that young children often only partly meet the Friedman criteria due to a lack of papilledema, emphasizing the need for pediatric-specific diagnostic criteria. Further large-scale studies are needed to confirm these findings and to explore the underlying reasons for this increase in venous pressure and potential new treatment avenues.

Correlation analysis of central venous pressure and Intra-thoracic pressures in Acute Respiratory Distress Syndrome mechanical ventilated patients, a pilot Study

Abstract Background Positive end expiratory pressure can affect measurement of central venous pressure through increased intrathoracic pressure. However, when positive end expiratory pressure (PEEP) is applied, central venous pressure and pleural pressure often increases more than right atrial pressure, so that transmural right atrial pressure (true filling pressure) decreases. Aim of the study Primary end point was to recognizing correlation coefficient between mean CVP and intra- thoracic pressures on volume-controlled mode and spontaneous modes on same population of mechanically ventilated ARDS patients. The secondary end point is to compare the correlation coefficient R during both modes with parameters of ventilatory settings. Patient and Methods A cohort observational prospective study was done enrolling single group of patients with acute respiratory distress syndrome, who necessitate mechanical ventilation more than two days after connection to ventilators, the study was performed with demonstration of central venous pressure in cmH2O upon application of needed PEEP. Central venous catheter inserted for measuring CVP were processed in accordance with the standard guidelines. Results There were statistically significant differences between control and support group regarding the PEEP, Plateau pressure, mean CVP and mean airway pressure MAP. The data were higher in control than support group with p-value &amp;lt;0.001, 0.002 and 0.004, respectively. There was statistically significant positive correlation between R and CVP in the control group with p &amp;lt; 0.001 and r = 0.918. There was statistically significant positive correlation between R and ΔPIT in support group with p 0.001 and r = 0.926. The correlation between CVP and R among the control group was R = 0.028 + 0.032 * CVP with p-value &amp;lt;0.001, whereas the correlation between ΔPIT and R among the support group was R = 0.465 + 0.020 * ΔPIT with p-value = 0.022 Conclusion The relation between hemodynamics change of central venous pressures and intrathoracic pressure is new independent marker for evaluating ARDS mechanically ventilated patients. Values of R correlation are different in controlled mode relative to spontaneous mode during ARDS ventilated patients.

Intracranial venous manometry in patients with idiopathic intracranial hypertension

Objective ‒ to analyse the results of cerebral angiography and venography with venous manometry in patients with medically refractory sdiopathic intracranial hypertension (IIH) and venous sinus stenosis.Materials and methods. Informed consent was obtained from each patient (parent or guardian) enrolled in the study and the study protocol conforms to the ethical guidelines of the Declaration of Helsinki as reflected in a priori approval by the Institutional Ethical Review Board (Institution's Human Research Committee). A retrospective analysis of the clinical and neuroimaging features of 9 patients with suspected IIH was performed. All patinets were treated at the SO «Scientific-Practical Center of Endovascular Neuroradiology NAMS of Ukraine» from January 2022 to January 2024. The criteria for inclusion in the study were: clinical symptoms of IIH without any other intracranial pathology according to imaging, lumbar pressure &gt;20 cm H2O, and symptoms refractory to medication treatment (optic disc edema, pulsatile tinnitus, etc.). Pressure gradients in contiguous sites were calculated for each patient in standard anatomical sites (superior sagittal sinus ‒ sinus drain, sinus drain ‒ transverse sinus, transverse sinus ‒ sigmoid sinus, sigmoid sinus ‒ internal jugular vein). The adjacent anatomical gradients were defined as the difference between the mean venous sinus pressure measurements in the venous sinuses where the manometry was performed. Pathological pressure gradients in the venous sinuses were defined as pressure gradients &gt;8 mm Hg based on established guidelines. Results. Out of the 9 patients with suspected IIH treated at the clinic, 2 patients were excluded. One female with combination of thrombosis in posterior third of superior sagittal sinus with left transverse sinus stenosis, the second (male) with bilateral jugular vein occlusions. Of the 7 patients (4 women and 3 men) with a mean age of 39.7 years, 4 (57.1 %) had pressure gradients &gt;8 mm Hg (transverse sine ‒ sigmoidal sine) and underwent sinus stenting. All procedures were successful. After stent implantation, control manometry was performed, which showed the gradient decreasing to 0‒2 mm Hg at the level of stenosis. The control examination after stenting was performed in all patients and showed regression of general cerebral symptoms, as well as varying degrees of ocular improvement. Conclusions. Our study evaluated the degree of pressure reduction in the anatomical sites of the cerebral venous system and showed a progressive decrease in pressure from the sigmoid sinus to the jugular vein. The venous sinus stenting leads to elimination of the pressure gradient, as well as neurological and ophthalmic improvement in carefully selected patients with refractory to conservative therapy IIH with a transstenotic pressure gradient &gt;8 mm Hg.

Association between early central venous pressure measurement and all-cause mortality in critically ill patients with heart failure: A cohort of 11,241 patients

BackgroundThe timing of central venous pressure (CVP) measurement may play a crucial role in heart failure management, yet no studies have explored this aspect. MethodsClinical information pertaining to patients in critical condition with a diagnosis of heart failure was retrieved from the MIMIC-IV database. The association between initial measurements of central venous pressure (CVP) and the incidence of mortality from all causes was analyzed using the Cox proportional hazards approach. Subgroup analysis and propensity score matching were conducted for sensitivity analyses. ResultsThis study included 11,241 participants (median age, 75 years; 44.70 % female). Utilizing restricted cubic spline and Kaplan–Meier survival analyses, it was determined that prognostic outcomes were better when CVP was measured within the initial 5-h window. Multivariate-adjusted 1-year (HR: 0.69; 95 % CI: 0.61–0.77), 90-day (HR: 0.70; 95 % CI: 0.62–0.80), and 30-day (HR: 0.67; 95 % CI: 0.57–0.78) all-cause mortalities were significantly lower in patients with early CVP measurement, which was proved robustly in subgroup analysis. Subsequent to the application of propensity score matching, a cohort of 1536 matched pairs was established, with the observed mortality rates continuing to be significantly lower among participants who underwent early CVP assessment. ConclusionsEarly CVP measurement (within 5 h) demonstrated an independent correlation with a decrease in both immediate and extended all-cause mortality rates among patients in critical condition suffering from heart failure.

Correlation of Internal Jugular Vein and Inferior Vena Cava Collapsibility Index with Direct Central Venous Pressure Measurement in Critically-ill Patients: An Observational Study.

Prompt assessments and quick replacement of intravascular fluid are critical steps to resuscitate hypovolemic patients. Intravascular volume assessment by direct central venous pressure (CVP) measurement is an invasive, time-consuming, and labor-intensive procedure. Nowadays, bedside ultrasound-guided volume assessment of the internal jugular vein (IJV) or inferior vena cava (IVC) is commonly employed as a proxy for direct CVP.Therefore, we examined the strength of association between CVP and collapsibility index (CI) of the IJV and IVC for evaluating the volume status of critically ill patients. Bedside USG-guided A-P diameter and cross-sectional area of the right IJV and IVC were measured, and their corresponding collapsibility indices were deduced. The results of the IJV and IVC indices were correlated with CVP. About 60 out of 70 enrolled patients were analyzed. The baseline clinical parameters of patients are shown in Table 1. For CSA and AP diameter, the correlations between CVP and IJV-CI at 0° were r = -0.107 (p = 0.001) and r = -0.092 (p = 0.001). Correlations between CVP and IJV-CI at 30° for CSA and diameter, however, were (r = -0.109, p = 0.001) and (r = -0.117, p = 0.001), respectively. Table 2 depicts the correlation between CVP and IVC-CI r = -0.503, p = 0.001 for CSA and r = -0.452, p = 0.001 for diameter. The IVC and IJV collapsibility indices can be used in place of invasive CVP monitoring to assess fluid status in critically ill patients. Kumar A, Bharti AK, Hussain M, Kumar S, Kumar A. Correlation of Internal Jugular Vein and Inferior Vena Cava Collapsibility Index with Direct Central Venous Pressure Measurement in Critically-ill Patients: An Observational Study. Indian J Crit Care Med 2024;28(6):595-600.

Venous Congestion Assessed by Venous Excess Ultrasound (VExUS) and Acute Kidney Injury in Children with Right Ventricular Dysfunction.

Right ventricular dysfunction (RVD) is a complication following congenital cardiac surgery in children and can lead to systemic venous congestion, low cardiac output, and organ dysfunction. Venous congestion can be transmitted backwards and adversely affect encapsulated organs such as the kidneys. To investigate the association between systemic venous congestion, as estimated by Venous Excess Ultrasound (VExUS), and the occurrence of acute kidney injury (AKI) in children with RVD following congenital heart surgery. Secondary objectives included comparing changes in VExUS scores after initiating treatment for RVD and venous congestion. This was a prospective observational study in children with RVD. The VExUS study was performed on day 1, day 2, and day 3 and categorized as VExUS-1, VExUS-2, and VExUS-3. Among 43 patients with RVD and dilated inferior vena cava, 19/43 (44%), 10/43 (23%), and 12/43 (28%) were VExUS-2 and VExUS-3, respectively. There was an association between severe RVD and elevated pulmonary artery systolic pressures and a VExUS score >2. A significant association was observed between central venous pressure (CVP) measurements and VExUS. Among 31 patients with a high VExUS score >2, 18 (58%) had AKI. Additionally, improvement in CVP and fluid balance was associated with improving VExUS scores following targeted treatment for RVD. VExUS serves as a valuable bedside tool for diagnosing and grading venous congestion through ultrasound Doppler. An elevated VExUS score was associated with the occurrence of AKI, and among the components of VExUS, portal vein pulsatility may be useful as a predictor of AKI. Natraj R, Bhaskaran AK, Rola P, Haycock K, Siuba MTT, Ranjit S. Venous Congestion Assessed by Venous Excess Ultrasound (VExUS) and Acute Kidney Injury in Children with Right Ventricular Dysfunction. Indian J Crit Care Med 2024;28(5):447-452.

Monitoring the venous circulation: novel techniques and applications.

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. 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. 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.

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

BackgroundColumn 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). MethodsA 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. ResultsThirty-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). ConclusionsObstruction 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.

The Ultrasound Hepato-Jugular Reflux: Measuring the Hepato-Jugular Reflux with Ultrasound with Comparison to Invasive Right Heart Catheterization

BackgroundUltrasound can overcome barriers to visualizing the internal jugular vein, allowing hepato-jugular reflux and jugular venous pressure measurement. We aimed to determine operating characteristics of the ultrasound hepato-jugular reflux and ultrasound jugular venous pressure predicting right atrial and pulmonary capillary occlusion pressures. MethodsIn a prospective observational cohort at three US academic hospitals the hepato-jugular reflux and jugular venous pressure were measured with ultrasound before right heart catheterization. Receiver operating curves, likelihood ratios, and regression models were utilized to compare the ultrasound hepato-jugular reflux and ultrasound jugular venous pressure to the right atrial and pulmonary capillary occlusion pressures. ResultsIn 99 adults undergoing right heart catheterization, an ultrasound hepato-jugular reflux had a negative likelihood ratio of 0.4 if 0 cm and a positive likelihood ratio of 4.3 if ≥ 1.5 cm for predicting a pulmonary capillary occlusion pressure ≥ 15 mmHg. Regression modeling predicting pulmonary capillary occlusion pressure was not only improved by including the ultrasound hepato-jugular reflux (P < .001), it was the more impactful predictor compared with the ultrasound jugular venous pressure (adjusted odds ratio 2.6 vs 1.2). The ultrasound hepato-jugular reflux showed substantial agreement (kappa 0.76; 95% confidence interval, 0.30-1.21), with poor agreement for the ultrasound jugular venous pressure (kappa 0.11; 95% confidence interval, -0.37-0.58). ConclusionIn patients undergoing right heart catheterization, the ultrasound hepato-jugular reflux is reproducible, has modest impact on the probability of a normal pulmonary capillary occlusion pressure when 0 cm, and more substantial impact on the probability of an elevated pulmonary capillary occlusion pressure when ≥ 1.5 cm.

Correlation between echocardiographic estimation of right atrial pressure and invasive measurement of central venous pressure in postoperative pediatric patients with congenital heart disease: a prospective observational study

BackgroundRight atrial pressure plays a critical role as a hemodynamic parameter in diagnosing pulmonary hypertension and other cardiac diseases, as well as guiding the treatment and prognosis of various cardiac disorders. If there is no obstruction between the inferior or superior vena cava (SVC) as central veins and the right atrium, the pressures in these veins could be considered equal to the right atrial pressure. This study aimed to examine the correlation between echocardiographic methods for estimating right atrial pressure and invasive measurements of central venous pressure (CVPi) in infants and children with congenital heart disease during the 48 h after cardiac surgery and to establish regression equations for echocardiographic estimation of central venous pressure (CVPe).ResultsWe prospectively enrolled 43 infants and children, ranging in age from 6 months to 16 years, including 20 males and 23 females. We found a significant correlation between CVPi and the ratio of the maximal diameter of IVC to the maximal diameter of the descending aorta ratio (IVCmax/DAOmax) (r = 0.529, P < 0.001), SVCS/D velocity ratio (SVCS/D) (r = 0.462, P = 0.006), right atrial vertical diameter (RAVD) (r = 0.409, P = 0.01), area (r = 0.384, P = 0.014), and tricuspid valve A wave acceleration rate (TVAAR) (r = 0.315, P = 0.048). Multiple regression analysis yielded an equation for estimating central venous pressure using four parameters related to the IVC, SVC, tricuspid valve, and right atrium. The equation is as follows: estimated CVP = 4.36 + (2.35 × IVCmax/DAOmax) + (1.06 × SVCS/D) + (0.059 × RAVD) + (0.001 × TVAAR). This equation is strongly correlated with CVPi (Pearson r = 0.698, P = 0.002).ConclusionsThe estimation of central venous pressure through a multi-parametric equation that included the ratio of the maximal diameter of the inferior vena cava to the maximal diameter of the descending aorta, the ratio of S to D velocity of the superior vena cava, the vertical diameter of the right atrium, and the acceleration rate of the A wave of the tricuspid valve demonstrated a robust correlation with invasively measured central venous pressure. To assess the accuracy of predicted pressures by this equation, further investigations are required to apply this innovative multi-parametric formula to a prospective population of pediatric patients with congenital heart disease.

The effect of different bed head angles on the hemodynamic parameters of intensive care patients lying in the supine position: A quasi-experimental study.

The aim of this study was to research the effect of different bed head angles on the hemodynamic parameters of intensive care patients lying in the supine position. This study was a non-randomized and non-controlled, quasi-experimental repeated measures study. The study was conducted with 50 intensive care patients aged 18 and over in a general surgery intensive care unit in Turkey. With each patient in the supine position, the bed head was raised to an angle of 0°, 20°, 30°, and 45° without a pillow, and the hemodynamic parameters of central venous pressure, systolic and diastolic blood pressure, heart rate, breathing rate, and peripheral oxygen saturation were recorded after 0 and 10 min. It was found that the mean central venous pressure value measured at min 0 and 10 was higher when the intensive care patients' bed head angle was raised to 45° than when the bed head was at an angle of 0° or 20° (p < .05). It was found that the patients' other hemodynamic parameters were not affected by different bed head angles. It was concluded as a result of this research that in intensive care patients in the supine position, only central venous pressure was affected by bed head angle, and that central venous pressure measurement can be reliably made at a bed head angle of 30°.

Treatment of Nutcracker Syndrome with Left Renal Vein Transposition and Endovascular Stenting

Nutcracker syndrome is a rare condition that occurs as a result of the entrapment of the left renal vein (LRV) between the aorta and the superior mesenteric artery. It is typically associated with symptoms such as left flank pain, hematuria, proteinuria, and pelvic congestion. The current treatment approach may be conservative in the presence of tolerable symptoms, and surgical or hybrid and stenting procedures in the order of priority in the presence of intolerable symptoms. The aim of this study is to review our experiences to evaluate the results of both methods in this series in which we have a greater tendency toward surgery instead of stenting. The clinical data of consecutive patients with nutcracker syndrome who underwent LRV transposition and LRV stenting between July 2019 and October 2023 were retrospectively reviewed. The patients were divided into 2 groups based on the methods of treatment: surgical and stenting. For procedure selection, LRV transposition was primarily recommended, with stenting offered to those who declined. Primary end points were morbidity and mortality. Secondary end points included late complications, patency, freedom from reintervention, and resolution of symptoms. Standard basic statistics and survival analysis methods were employed. Nineteen patients with nutcracker syndrome (female: 100%) were treated with LRV stentings (n=5) and LRV transposition (n=14). The mean age was 24 (20-27, interquartile range [IQR]) years. The mean follow-up was 23 (9-32, IQR) months. There were no major complications and mortality after both procedures. The most frequent sign and symptom associated with LRV entrapment were left flank pain 100% (n=19), proteinuria 88% (n=15), and hematuria 47% (n=9). The mean peak velocity ratio on Doppler ultrasound was 6.13 (6-6.44, IQR). Aortomesenteric angle, beak angle (beak sign), and mean diameter ratio on computed tomography were 26° (22.6-28.5, IQR), 25° (23.9-28, IQR), and 5.3 (5-6, IQR), respectively. Venous pressure measurements were only used to confirm the diagnosis in 5 patients in the stenting group. The measured renocaval gradient was 4 (3.9-4.4, IQR) mm Hg. After both procedures, the classical symptoms, including left flank pain, proteinuria, and hematuria, resolved in 89.5% (n=17), 57.8% (n=11), and 82.3% (n=15) of the cases, respectively. A total of 4 patients required reintervention, 3 patients after LRV transposition (occlusion, n=2; stenosis, n=1), and 1 patient after stenting (occlusion, n=1). The 1-year and 3-year primary patency for the 19 patients was 87% and 80%, respectively. Three-year primary-assisted patency was 100%. Similarly, the 1-year and 3-year freedom from reintervention rate was 83% and 72%, respectively. Additionally, the 1-year and 3-year primary patency for the surgical group was 91% and 81%, respectively, and the 1-year and 3-year primary patency for the stenting group was 75%. Nutcracker syndrome should be kept in mind in cases where flank pain and hematuria cannot be associated with kidney diseases. Radiographic evidence must be accompanied by serious symptoms to initiate the treatment of nutcracker syndrome with LRV transposition and endovascular stenting procedures. Both procedures, along with their respective advantages and disadvantages, can be preferred as primary treatments for nutcracker syndrome. Our study demonstrates that both procedures can be safely and effectively performed, yielding good outcomes.

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

PurposeTo compare the results of retinal venous pressure (RVP) measurement performed with contact lens dynamometry (CLD) and with the new IOPstim.MethodsIn 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 examinationsThree 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.ResultsPressures 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.ConclusionIn 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.

Assessment of renal congestion in a rat model with congestive heart failure using superb microvascular imaging.

Renal congestion is a therapeutic target in congestive heart failure. However, its detailed evaluation in a clinical setting is challenging. This study sought to assess renal congestion impairment using superb microvascular imaging (SMI), a simple and accessible method. Dahl salt-sensitive rats, used as a model for congestive heart failure, underwent central venous pressure (CVP) measurements. Renal congestion was evaluated through measurements of renal medullary pressure (RMP) and assessment of renal perfusion using contrast-enhanced ultrasonography at both the early (control group) and heart failure phases (HF group). All rats were assessed with SMI. The region of interest (ROI) was set in interlobular vessels, interlobar vessels, and a combination of these areas. The area ratio was calculated from the color pixel count in the ROI divided by the total pixel count in the ROI. Intrarenal perfusion index (IRPI) was defined as (maximum area ratio-minimum area ratio) / maximum area ratio. There were no significant differences in renal function and left ventricular ejection fraction between the two groups. CVP, time-to-peak (TTP) in the medulla, and RMP were higher in the HF group than in the control group. In the HF group, IRPI, evaluated in the interlobular vessels, was significantly higher than in the control group. IRPI was positively correlated with TTP in the medulla (p = 0.028, R = 0.60) and RMP (p < 0.001, R = 0.84), indicating that IRPI reflected renal congestion. IRPI is a useful tool for assessing renal congestion in rats with congestive heart failure.

Feasibility and safety of ultrasound-guided percutaneous transhepatic measurement of portal venous pressure.

The measurement of portal venous pressure (PVP) has been extensively studied, primarily through indirect methods. However, the potential of ultrasound-guided percutaneous transhepatic PVP measurement as a direct method has been largely unexplored. This study aimed to investigate the accuracy, safety, and feasibility of this approach. In vitro, the experiment aimed to select a needle that could accurately transmit pressure, had a small inner diameter and was suitable for liver puncture, and performed on 20 healthy New Zealand white rabbits. An ultrasound-guided percutaneous transhepatic portal vein puncture was undertaken to measure PVP. Additionally, free hepatic venous pressure (FHVP) and wedged hepatic venous pressure (WHVP) were measured under digital subtraction angiography (DSA). The correlation between the two methods was assessed. Enroll study participants from October 18, 2023 to November 11, 2023 with written informed consent. Five patients were measured the PVP under ultrasound guidance before surgery to determine the feasibility of this measurement method. There was no significant difference in the results obtained using 9 different types of needles (P > 0.05). This demonstrated a great repeatability (P < 0.05). The 22G chiba needle with small inner diameter, allowing for accurate pressure transmission and suitable for liver puncture, was utilized for percutaneous transhepatic PVP measurement. There were positive correlations between PVP and HVPG (r = 0.881), PVP and WHVP (r = 0.709), HVPG and WHVP (r = 0.729), IVCP and FHVP (r = 0.572). The PVP was accurately and safely measured in 5 patients with segmental hepatectomy. No complications could be identified during postoperative ultrasound. Percutaneous transhepatic portal venous puncture under ultrasound guidance is accurate, safe and feasible to measure portal venous pressure. This study has been registered in the Chinese Clinical Trial Registry with registration number ChiCTR2300076751.

Idiopathic intracranial hypertension: cranial magnetic resonance imaging findings correlation with direct venous sinus pressure measurements

Idiopathic intracranial hypertension: cranial magnetic resonance imaging findings correlation with direct venous sinus pressure measurements

Advantages of using ultrasound diagnostic methods in the practice of an anesthesiologist on the example of neurosurgical interventions in the sitting position in pediatric patients with brain tumors

The purpose of the publication is to improve the results of treatment of children with brain tumors with the help of high-quality monitoring during neurosurgical operations with the localization of pathological formations that require the patient to be in a sitting position; encourage anesthesiologists to acquire the necessary additional skills in ultrasound diagnostics.For the description of the clinical case, the authors obtained the written informed consent of patients No. 1 and No. 2 to use the materials of his medical history in the article, in accordance with the Ethical Standards of Legal Regulation of Relations.Two clinical cases of anesthesiological management of patients with neurooncopathology (neoplasm of the left cerebellar peduncle with prolapse in the IV ventricle area and volume formation of the pineal area) operated on in the sitting position with standard monitoring (pulse oximetry, electrocardiography, non-invasive measurement of arterial blood pressure, thermometry, capnography, other gas analyzer), supplemented by invasive measurement of central venous pressure, bispectral index (BIS) monitoring, neurophysiological parameters, transesophageal echocardiography (the sensor is selected according to the patient's age). Clinical, laboratory, biochemical, ultrasound, endoscopic, x-ray methods, computer and magnetic resonance imaging were used to establish a diagnosis, determine the nature of complications, choose access and methods of surgical intervention, evaluate the effectiveness of treatment and diagnostics.The sitting position during surgery is the neurosurgeon’s choice because this position improves access to the tumor, reduces the volume of blood loss and intracranial pressure, but increases the risk of intraoperative complications, in particular, air embolism, which was diagnosed by echocardiography. The National Children’s Specialized Hospital «Okhmatdyt» has the necessary equipment (in particular, a neurosurgical chair) for performing neurosurgical interventions in a sitting position. During the surgical intervention, in one clinical case, an air embolism of the 2nd degree according to the Tubingen scale was recorded, without other changes according to the measurement of arterial and central venous pressure, BIS and neurophysiological monitoring. In the second case, an air embolism of the 1st degree was recorded. Both patients were extubated on the operating table at the end of the operation and were observed during the day in the intensive care unit. The early postoperative period was uneventful. According to the control magnetic resonance imaging, postoperative moderate pneumocephalus developed, which did not require repeated surgical intervention. During the operation, monitoring was carried out using pulse oximetry and electrocardiography.This article does not aim to review the specific indications for transesophageal echocardiography or a comprehensive description of all complications that can be visualized using this method during operative neurosurgical interventions. This article presents two cases that demonstrate the success of using this method by an anesthesiologist. According to the authors, it is advisable to introduce the use of ultrasound methods into the daily practice of an anesthesiologist.High-quality monitoring is important for early detection and prevention of complications. Thanks to the professionalism and expanded arsenal of practical skills of the team of doctors of the NCSH «Okhmatdit», in particular, anesthesiologists, in both cases, high-tech medical care was provided with a good prognosis for the future life of these patients.