Venous Flow Research Articles

Attenuation of irradiated choroid and its regional vortex veins in central serous chorioretinopathy after photodynamic therapy

We retrospectively studied 12 eyes of 12 patients with central serous chorioretinopathy (CSC) to investigate choroidal thickness changes following half-fluence photodynamic therapy (PDT) using widefield choroidal thickness maps obtained by optical coherence tomography (OCT). Additionally, we assessed the relationship between choroidal thickness changes and the regional vortex veins as visualized on widefield en face OCT of the choroid. Pre-treatment en face images of the choroidal vasculature were superimposed on subtracted choroidal thickness maps before and 3 months after half-fluence PDT. The choroidal thickness decreased mainly in the irradiated macular area and in the region of vortex veins which function as drainage for the macula in all eyes. Eleven eyes (91.7%) showed choroidal thinning in the nasal area which overlapped with the nasal vortex vein distribution. Moreover, in 10 (90.9%) of those eyes, we observed intervortex venous anastomosis across the vertical watershed zone. Quantitative analysis revealed that the reduction in choroidal thickness was most pronounced in the macular area. Furthermore, the choroidal thickness reduction in the area with macular drainage vortex veins was significantly greater than that in the area without such vortex veins. These results suggest that half-fluence PDT might decrease choroidal thickness due to choriocapillaris occlusion in the irradiated macula, possibly leading to diminished venous drainage from the macula to regional vortex veins. Moreover, venous blood flow through the anastomotic vessels from the macular drainage vortex veins into the nasal vortex veins might be reduced post-treatment.

Afferent venous perfusion of fetal liver: umbilical and portal blood-flow volumes in fetuses born small-for-gestational age.

To quantify the dynamic changes in the afferent venous flow volume of the liver in low-risk pregnancies with fetuses born small-for-gestational age. This was a prospective study of low-risk singleton pregnancies with estimated fetal weight (EFW) and birth weight ≤ 10th centile attending for a routine second- or third-trimester ultrasound examination. Their umbilical and portal blood-flow volumes were compared with those of a control group of fetuses born appropriate-for-gestational age from which normal reference ranges were constructed. Absolute and Z-score differences between the groups were assessed. In total, 133 fetuses were included in the study group and 362 in the control group. The mean umbilical blood-flow volume in the study group, both absolute and normalized per kg of EFW, was below that of the appropriate-for-gestational-age fetuses for most of the period of pregnancy studied (overall mean Z-score, -0.82 and -0.84, respectively). In contrast, the mean portal blood-flow volume, per kg of EFW, showed the opposite trend (overall mean Z-score, +0.86), reaching its maximum level (+1.43) in the late third trimester. This resulted in a steep decrease in the mean placental-to-portal-blood-flow volume ratio, from 14.4 at 24 weeks of gestation (above the 60th centile) to 4.7 at 38 weeks of gestation (15th centile), corresponding to Z-scores of +0.4 and -1.02, respectively. In fetuses born small-for-gestational age, the ratio of blood-flow volume in the umbilical vein to that in the portal vein decreases consistently during pregnancy, and to a greater extent compared with those born appropriate-for-gestational age, reaching a lower nadir in the third trimester. This additional redistribution of liver perfusion affects negatively fetal growth even in low-risk pregnancy, and should be taken into account when planning delivery. We suggest considering liver venous perfusion as an ancillary tool for monitoring small-for-gestational-age pregnancies. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Патофізіологічні механізми тромбозу глибоких вен

Deep venous thrombosis is a frequent multifactorial disease and most of the time is triggered by the interaction between acquired risk factors, particularly immobility, and hereditary risk factors such as thrombophilias. The mechanisms underlying deep venous thrombosis are not fully elucidated; however, in recent years the role of venous flow, endothelium, platelets, leukocytes, and the interaction between inflammation and hemostasis has been determined. Alteration of venous blood flow produces endothelial activation, favoring the adhesion of platelets and leukocytes, which, through tissue factor expression and neutrophil extracellular traps formation, contribute to the activation of coagulation, trapping more cells, such as red blood cells, monocytes, eosinophils, lymphocytes. The coagulation factor XI-driven propagation phase of blood coagulation plays a major role in venous thrombus growth, but a minor role in hemostasis. In this work, the main mechanisms involved in the pathophysiology of deep vein thrombosis are described.

Surgical experience in repairing the right common carotid artery and the right internal jugular vein after ECMO in neonates: early clinical results

BackgroundThe purpose of this study was to summarize the early clinical results and surgical experience of repairing the right common carotid artery and the right internal jugular vein after ECMO treatment in neonates.MethodsWe retrospectively collected the clinical data of 16 neonates with circulatory and respiratory failure who were treated with ECMO via the right common carotid artery and the right internal jugular vein in our hospital from June 2021 to December 2022. The effects of repairing the common carotid artery and internal jugular vein were evaluated.ResultsAll 16 patients successfully underwent right cervical vascular cannulation, and the ECMO cycle was successfully established. Twelve patients were successfully removed from ECMO. The right common carotid artery and the right internal jugular vein were successfully repaired in these 12 patients. There was unobstructed arterial blood flow in 9 patients, mild stenosis in 1 patient, moderate stenosis in 1 patient and obstruction in 1 patient. There was unobstructed venous blood flow in 10 patients, mild stenosis in 1 patient, and moderate stenosis in 1 patient. No thrombosis was found in the right internal jugular vein. Thrombosis was found in the right common carotid artery of one patient.ConclusionRepairing the right common carotid artery and the right internal jugular vein after ECMO treatment in neonates was feasible, and careful surgical anastomosis techniques and standardized postoperative anticoagulation management can ensure early vascular patency. However, long-term vascular patency is still being assessed in follow-up.

Hemodynamic evaluation of right-sided congestion with doppler ultrasonography in pulmonary hypertension: portal vs intra-renal venous flow patterns

Abstract Introduction Renal congestion is a key pathophysiological mechanism mediating adverse outcomes in patients with heart failure. Novel approaches to evaluate renal congestion like renal Doppler ultrasonography show promise as a noninvasive hemodynamic monitoring tool. Portal Doppler ultrasound is a less challenging exam and could potentially provide similar information than intra-renal Doppler. Methods and Results We enrolled 95 patients with suspected or diagnosed pulmonary hypertension (PH) presenting to the emergency department or to a scheduled ambulatory clinic. Patients underwent renal and portal Doppler ultrasonography. Renal congestion was graded using the validated renal venous stasis index (RVSI) or renal venous patterns. The portal vein pulsatility fraction (PVPF) was used to quantify portal congestion. We found high degree of correlation (R = 0.93) between portal and renal congestion, with excellent agreement (κ = 0.92 [0.86-0.98]). Both RVSI and PVPF showed excellent interclass correlation and agreement amongst operators (ICC 0.93). 90-day mortality or need for renal replacement therapy was significantly more frequent in patients with high PVPF (p=0.001) HR: 5.3 (1.9-17.0). Conclusions Altered portal venous flow accurately predicts the presence of renal congestion and is technically easier to obtain. Portal vein Doppler may identify patients with pulmonary hypertension at risk for renal deterioration secondary to venous congestion.Portal-renal patterns and their outcomes

Pulmonary venous flow changes after Mitraclip implantation is predictor of mid-term right ventricular function improvement

Abstract Background Percutaneous mitral valve repair with Mitraclip has become an effective therapeutic alternative to mitral valve surgery in high-risk surgical patients with severe mitral regurgitation. Pulmonary venous flow assessment by pulsed Doppler is widely used to determine the severity of mitral regurgitation and apparently is the best method to evaluate mitral regurgitation after the procedure because device artifacts do not affect it. The main objective of this study was to assess the impact of pulmonary venous flow changes after Mitraclip implantation in right ventricular function in the follow up at 6 months after the procedure. Methods This single-center, retrospective study included all consecutive patients with mitral regurgitation ≥ III/IV undergoing percutaneous mitral valve repair with the MitraClip device at our institution between 2010 and 2023. We analyzed the changes in the systolic/diastolic flow velocity time integral ratio in pulmonary veins pre and postprocedure. The tricuspid annular plane systolic excursion (TAPSE) was the method used to assess the right ventricular function in the follow up. Results A total of 158 consecutive patients that underwent Mitraclip implantation at our institution were included. Men age was 77 years ±10.3, and 82 patients (52.5%) were women. The etiology of mitral regurgitation was degenerative in 70 patients (44.3%), functional in 60 patients (37.9%) and mixed in 28 patients (17.7%). Preprocedurally, tridimensional effective regurgitant orifice was 0.63 ±0.33cm2, left ventricular end-diastolic volume 145.19 ± 66.14 ml (indexed 80.33 ± 59.59 ml/m2), left ventricular ejection fraction 45.90 ± 15.99%, pulmonary artery systolic pressure (PASP) 48.79 ± 18.12 mmHg and TAPSE 18.59 ± 4.43mm. The change in the pulmonary venous flow assessed by the systolic/diastolic flow velocity time integral ratio, was predictor of a right ventricular function improvement at 6 months (y = -2.7169 + 3.0171 x, r= 0.45, p= 0,006 see figure 1). Conclusions Pulmonary venous flow changes after Mitraclip implantation assessed by the systolic/diastolic flow velocity time integral ratio is predictor of mid-term right ventricular function improvement.Figure 1

Impact of collateral vessels on Fontan circulation by using 0-1 dimensional Fontan circulation model considering concepts of oxygen supply and consumption

Abstract Background/Purpose In patients with univentricular heart disease, the Fontan operation has played a significant role in improving cyanosis and reducing the volume load on the systemic ventricle. However, Fontan patients may develop various complications, and their hemodynamics may deteriorate gradually, resulting in a poor long-term survival rate. Development of collateral vessels before and/or after the Fontan operation is one of the significant problems, and the patients may suffer from advanced cyanosis and heart failure. Although recent studies about the collateral vessels by MRI showed that a significant amount of blood is flown through the collateral vessels, little is known about its effect on the Fontan circulation. Therefore, understanding the mechanism and impact of collateral vessels on the Fontan circulation is important. Methods A 0-1-dimensional Fontan circulation hemodynamic model was developed to reproduce the hemodynamic changes of the blood flow in the entire body by introducing two types of collateral vessels (VVC: veno-venous collateral, APC: aorto-pulmonary collateral) into the model considering clinical status. Also, giving various conditions by ranging catecholamine dose and introducing the concept of oxygen delivery and consumption by changing workloads, arterial and central venous oxygen saturations (SaO2 and SvO2) are predicted in the Fontan circulation models. To evaluate the cardiac function, considering the impact of collateral vessels, four representative values were examined: (1) cardiac output (CO) per minute; (2) Ees relative to arterial elastance (Ees/Ea); (3) ejection fraction; and (4) the stroke work (SW) to pressure-volume area (PVA) ratio (SW/PVA). Results SaO2 and SvO2 were less in Fontan circulations with both VVC and APC present (92% and 54%) than those without collateral vessels (96% and 62%). Also, with collateral vessels, Ees/Ea was decreased while SW/PVA was increased, leading to poor perfusion to the tissue. Regardless of the presence or absence of collateral circulation, SaO2 and SvO2, and systemic blood flow rate decreased when pulmonary vascular resistance was high. By administering catecholamine at 10 microgram/kg/min, in the presence of both VVC and APC, SvO2 was increased from 53% to 58%, while SaO2 was decreased from 92% to 88%. Conclusions The simulated results of arterial and venous blood oxygen saturations and systemic blood flow rate were well-reproduced, matching the previously reported clinical results. It is suggested that pulmonary vasodilators may be beneficial in increasing blood oxygen saturation and improving tissue perfusion, even in Fontan patients with collateral vessels. However, the catecholamine's positive effect is limited. For reproducing various conditions of Fontan circulations, it is necessary to collect actual measurement data from a variety of patients and validate the predicted value to increase the credibility of the model.Arterial and venous oxygen saturationsPressure and volume curves

Abstract 14822: Portopulmonary Hypertension Unveiled: Effects of Transjugular Intrahepatic Portopulmonary Shunt Placement

Introduction: Transjugular intrahepatic portosystemic shunts (TIPS) treat portal hypertension by connecting the portal vein to the hepatic vein in the liver. The resultant shunting of portal venous flow to the systemic circulation helps reduce the portosystemic gradient and is used to treat complications of portal hypertension. Right heart failure and the development of pulmonary hypertension after TIPS are known complications; however, portopulmonary hypertension (POPH) is rare. Description of Case: A 61-year-old male presents to the clinic for six months of exertional dyspnea, weight gain, and lower extremity edema. He has a history of coronary artery disease and nonalcoholic steatohepatitis cirrhosis, with TIPS placement four years prior for esophageal variceal bleeding. An echocardiogram revealed right ventricular (RV) dilatation with moderately reduced function, a flattened left ventricular septum, and an estimated pulmonary artery systolic pressure of 91 mmHg. An echocardiogram and right heart catheterization (RHC) performed before his TIPS showed normal RV function and pulmonary artery pressures (PAP). Decision Making: The patient was promptly started on furosemide and spironolactone, and after adequate diuresis, a repeat RHC was obtained, which showed significantly elevated PAP, and normal left-sided filling pressures and cardiac output. Other causes of pulmonary hypertension were ruled out, and the patient was started on tadalafil monotherapy for severe POPH, with significant improvement in his PAP (Table 1). Conclusion: POPH after TIPS is a rare complication that should be suspected in patients presenting with signs of right-sided volume overload. The mechanism by which TIPS leads to POPH is not entirely understood. The degree of RV dysfunction correlates with mortality, and prompt treatment is warranted.

Abstract 17257: Aortopulmonary Collateral Burden in the Fontan Circulation: Longitudinal Changes and Relationship With Clinical Outcomes

Background: Aortopulmonary collaterals (APC) are a common source of volume load in patients with a Fontan circulation and their burden can be quantified by CMR. Longitudinal trends in APC flow and their relationship with outcomes have not been described. Hypothesis: Higher APC flow will be associated with worse clinical outcomes in Fontan patients. Aims: To assess longitudinal changes in APC flow in the Fontan circulation using CMR and their relationship with outcomes. Methods: Single-center retrospective analysis of Fontan patients who had at least 1 CMR with APC flow data. APC flow was estimated as the difference between aortic and systemic venous flows and also expressed as a percent of aortic flow. Primary outcome was a composite of death or heart transplantation; secondary outcomes included protein losing enteropathy, ascites, chylothorax, and hemoptysis. The baseline (time at Fontan=time 0) and trend in APC flow were estimated using a linear mixed model with a random intercept and slope for each patient. Results: Analysis included 758 CMRs from 356 patients; 123 of whom had ≥ 2 CMRs. Median age at first CMR was 14 y (IQR 10-19 y) and median CMRs per patient were 2 (range 1-12). Baseline APC flow was 0.6 (±0.5) L/min/m 2 or 17 (±10) % of aortic flow. Increasing APC flow over time correlated with increasing trend in ventricular dilation and decreasing trend in SaO 2 . Over a median follow-up of 17 years, 22 patients (6%) had the composite outcome. High baseline APC flow as well as an increasing trend in APC flow were associated with clinical outcomes including an independent association with death or heart transplantation (Table). Conclusions: APCs represent a significant hemodynamic burden in functional single ventricle hearts palliated to the Fontan circulation. Higher and increasing APC flow is associated with worse clinical outcomes. Factors contributing to APC development and whether APC occlusion results in a lasting reduction in the burden remain to be elucidated.

Quantifying the Effect of Acoustic Parameters on Temporal and Spatial Cavitation Activity: Gauging Cavitation Dose.

Cavitation-enhanced delivery of therapeutic agents is under development for the treatment of cancer and neurodegenerative and cardiovascular diseases, including sonothrombolysis for deep vein thrombosis. The objective of this study was to quantify the spatial and temporal distribution of cavitation activity nucleated by Definity infused through the EKOS catheter over a range of acoustic parameters controlled by the EKOS endovascular system. Three insonation protocols were compared in an in vitro phantom mimicking venous flow to measure the effect of peak rarefactional pressure, pulse duration and pulse repetition frequency on cavitation activity energy, location and duration. Inertial and stable cavitation activity was quantified using passive cavitation imaging, and a metric of cavitation dose based on energy density was defined. For all three insonation protocols, cavitation was sustained for the entire 30min Definity infusion. The evolution of cavitation energy during each pulse duration was similar for all three protocols. For insonation protocols with higher peak rarefactional acoustic pressures, inertial and stable cavitation doses also increased. A complex relationship between the temporal behavior of cavitation energy within each pulse and the pulse repetition frequency affected the cavitation dose for the three insonation protocols. The relative predominance of stable or inertial cavitation dose varied according to insonation schemes. Passive cavitation images revealed the spatial distribution of cavitation activity. Our cavitation dose metric based on energy density enabled the impact of different acoustic parameters on cavitation activity to be measured. Depending on the type of cavitation to be promoted or suppressed, particular pulsing schemes could be employed in future studies, for example, to correlate cavitation dose with sonothrombolytic efficacy.

Feasibility of MRI assessment of maternal-fetal oxygen transport and consumption relative to maternal position in healthy late gestational pregnancies.

Late gestational supine positioning reduces maternal cardiac output due to inferior vena caval (IVC) compression, despite increased collateral venous return. However, little is known about the impact of maternal position on oxygen (O2 ) delivery and consumption of the gravid uterus, fetus, placenta and lower limbs. We studied the effects of maternal positioning on these parameters in 20 healthy pregnant subjects at 36±2weeks using magnetic resonance imaging (MRI); a follow-up MRI was performed 6-months postpartum (n=16/20). MRI techniques included phase-contrast and T1/T2 relaxometry for blood flow and oximetry imaging, respectively. O2 transport was measured in the following vessels (bilateral where appropriate): maternal abdominal descending aorta (DAoabdo ), IVC, ovarian, paraspinal veins (PSV), uterine artery (UtA) and external iliacs, and umbilical. Maternal cardiac output was measured by summing DAothoracic and superior vena cava flows. Supine mothers (n=6) had lower cardiac output and O2 delivery in the DAoabdo , UtA and external iliac arteries, and higher PSV flow than those in either the left (n=8) or right (n=6) lateral positions during MRI. However, O2 consumption in the gravid uterus, fetus, placenta and lower limbs was unaffected by maternal positioning. The ratio of IVC/PSV flow decreased in supine mothers while ovarian venous flow and O2 saturation were unaltered, suggesting a major route of pelvic venous return unaffected by maternal position. Placental-fetal O2 transport and consumption were similar between left and right lateral maternal positions. In comparison to non-pregnant findings, DAoabdo and UtA O2 delivery and pelvic O2 consumption increased, while lower-limb consumption remained constant , despite reduced external iliac artery O2 delivery in late gestation. KEY POINTS: Though sleeping supine during the third trimester is associated with an increased risk of antepartum stillbirth, the underlying biological mechanisms are not fully understood. Maternal cardiac output and uteroplacental flow are reduced in supine mothers due to inferior vena caval compression from the weight of the gravid uterus. This MRI study provides a comprehensive circulatory assessment, demonstrating reduced maternal cardiac output and O2 delivery (uteroplacental, lower body) in supine compared to lateral positioning; however, O2 consumption (gravid uterus, fetus, placenta, lower limbs) was preserved. Unlike other mammalian species, the ovarian veins conduct substantial venous return from the human pregnant uterus that is unaffected by maternal positioning. Lumbar paraspinal venous flow increased in supine mothers. These observations may have important considerations during major pelvic surgery in pregnancy (i.e. placenta percreta). Future studies should address the importance of maternal positioning as a potential tool to deliver improved perinatal outcomes in pregnancies with compromised uteroplacental O2 delivery.

Downhill varices in the hypopharynx due to huge thyroid tumor: a case report.

Downhill varices are usually caused by superior vena cava (SVC) obstruction due to bronchogenic carcinoma or mediastinal tumors. These structures show retrograde blood flow and are located in the proximal esophagus. Varices in the hypopharynx resulting from mediastinal thyroid tumor are extremely rare. A 70-year-old man visited a local hospital with a 35-year history of enlarging thyroid tumor in the right neck. Fine needle aspiration cytology of the tumor revealed benign goiter. Contrast-enhanced computed tomography showed a huge tumor (13×10×5 cm) in the right to left lobe of the thyroid extending into the mediastinum. Further, a well-enhanced mass mimicking hypopharyngeal cancer was identified in the hypopharynx. Endoscopic examination demonstrated varices in the postcricoid region, so we avoided biopsy. The preoperative diagnosis was huge adenomatous goiter and hypopharyngeal varices caused by obstruction of the internal jugular and brachiocephalic vein by the goiter. Total thyroidectomy was performed and hypopharyngeal varices had disappeared by the next day. The histopathological diagnosis of the thyroid tumor was poorly differentiated carcinoma. Mediastinal thyroid tumor rarely causes downhill varices due to SVC obstruction. However, in this case, signs of SVC obstruction were absent and varices were found not in the upper esophagus, but in the hypopharynx. Obstructed venous flow from the thyroid plexus might circulate via superior laryngeal vein and cause varices in the postcricoid region. When a patient with large mediastinal tumor shows a tumor-like lesion in the hypopharynx, considering the possibility of downhill varices is important before conducting immediate biopsies.

Development and validation of a nomogram to predict allograft survival after pediatric liver transplantation.

Liver transplantation is the main treatment for cholestatic liver disease and some metabolic liver diseases in children. However, no accurate prediction model to determine the survival probability of grafts prior to surgery exists. This study aimed to develop an effective prognostic model for allograft survival after pediatric liver transplantation. This retrospective cohort study included 2032 patients who underwent pediatric liver transplantation between January 1, 2006, and January 1, 2020. A nomogram was developed using Cox regression and validated based on bootstrap sampling. Predictive and discriminatory accuracies were determined using the concordance index and visualized using calibration curves; net benefits were calculated for model comparison. An online Shiny application was developed for easy access to the model. Multivariable analysis demonstrated that preoperative diagnosis, recipient age, body weight, graft type, preoperative total bilirubin, interleukin-1β, portal venous blood flow direction, spleen thickness, and the presence of heart disease and cholangitis were independent factors for survival, all of which were selected in the nomogram. Calibration of the nomogram indicated that the 1-, 3-, and 5-year predicted survival rates agreed with the actual survival rate. The concordance indices for graft survival at 1, 3, and 5 years were 0.776, 0.757, and 0.753, respectively, which were significantly higher than those of the Pediatric End-Stage Liver Disease and Child-Pugh scoring systems. The allograft dysfunction risk of a recipient could be easily predicted using the following URL: https://aspelt.shinyapps.io/ASPELT/ / CONCLUSION: The allograft survival after pediatric liver transplantation (ASPELT) score model can effectively predict the graft survival rate after liver transplantation in children, providing a simple and convenient evaluation method for clinicians and patients.

The Effect of Superficial Venous Incompetence Treatment on Combined Segmental Deep Venous Reflux

The aim of this study was to assess the role of treatment of superficial venous reflux (SVR) in patients with combined deep segmental venous reflux as regards clinical symptoms as well as reflux improvement of the deep veins. We reviewed 80 patients, retrospectively selected on the inclusion criteria and having combined SVR and segmental deep venous reflux who underwent SVR ablation. The contralateral limb of 44 patients was used as a control group, asked to wear compression stockings for 3months during day time with no surgical intervention. Duplex ultrasounds follow-up was performed at 3, 6, and 12months postoperatively. Clinical severity of venous disease was graded from C1 to C6 according to the CEAP (Clinical, Etiology, Anatomy, and Pathophysiology) classification. Duplex ultrasound was done in both supine and standing positions with non-weight-bearing of the examined limb. The venous reflux time, the venous flow volume and the peak venous flow velocity were registered. Removal of SVR was performed using either conventional surgery or radiofrequency ablation. The patient was required to wear compression stockings during the day time for the following weeks. During the follow-up period, all patients were improved clinically as regards pain, edema, and ulcer healing. All patients included in this study had no signs of residual SVR. Corrected deep venous segment reflux was in 36 (45%). Similar data at 3, 6, and 12months postoperatively after SVR removal. The popliteal vein reflux responded less than the femoral vein reflux did. Treatment of the SVR eliminates segmental deep venous reflux in a good percentage of patients regardless of the treatment modality. Also, symptoms improvement and ulcer healing were documented, and hence, more studies are recommended to evaluate this role.

Supracardiac Total Anomalous Pulmonary Venous Connection in Adolescence.

Background Supracardiac total anomalous pulmonary communication (TAPVC) constitutes a rare congenital cardiac anomaly. Most babies with supracardiac TAPVC are diagnosed in infancy and undergo complete surgical repair during infancy. Delayed presentation of supracardiac TAPVC is rare, and the surgical outcomes are not well known. This retrospective study was conducted to determine the presentation and surgical outcome of supracardiac TAPVC among adolescents, which constitutes an extremely rare subgroup of TAPVC. Methodology This retrospective analysis was conducted among 15 adolescent patients with supracardiac TAPVC who underwent surgical repair in the cardiothoracic surgery department of a tertiary care center in India. This study aimed to assess the intraoperative, postoperative, immediate, early, and late outcomes of adolescent patients with supracardiac TAPVC who had undergone surgical repair between 2010 and 2014 in a tertiary care center in India. Results The study included 15 patients with a diagnosis of isolated supracardiac TAPVC. A mild degree of cyanosis was present in eight patients, recurrent episodes of lower respiratory tract infections were present in five patients, and dyspnea (New York Heart Association I/II) was noted in 12 patients. Mean oxygen saturation was 92% (range = 85-93%), and mean pulmonary artery pressure was 24 mmHg (range = 15-50 mmHg). After median stenotomy, a wide anastomosis was made between the common pulmonary venous chamber and the posterior wall of the left atrium. A fenestration was made in the Dacron patch in three patients who had raised pulmonary vascular resistance (PVR) preoperatively. Twelve patients were weaned off cardiopulmonary bypass (CPB) with minimal inotropic support. Three patients who had high preoperative PVR had difficulty in weaning from CPB. The mean CPB and cross-clamp time was 75 ± 12 minutes and 58 ± 9 minutes, respectively. Atrial fibrillation was noted in five (33.3%) patients in the early postoperative period, and three (20%) patients had pulmonary artery hypertensive crises postoperatively. There was no superficial or deep sternal wound infection in the postoperative period. Mild and moderate right ventricular dysfunction was present in four (26.67%) and two (13.3%) patients, respectively, in the postoperative period. On two-dimensional echocardiography during follow-up at the end of one year, there was no gradient across the anastomosis, and pulmonary artery pressure was normal in all patients. Conclusions Surgical repair of supracardiac TAPVC in adolescence has an excellent outcome. Survival of patients with supracardiac TAPVC until adolescence depends on the presence of a dilated vertical vein and a large atrial septal defect facilitating unobstructed pulmonary venous flow. The aim of the surgical repair should be to create a wide anastomosis between the left atrium and the pulmonary venous chamber which should be bigger than the size of the mitral valve orifice indexed to the body surface area as it would amount to no or negligible anastomotic gradient postoperatively.

Acoustic Properties of Stretchable Liquid Metal‐Elastomer Composites for Matching Layers in Wearable Ultrasonic Transducer Arrays

AbstractUltrasound is a safe, noninvasive diagnostic technique used to measure internal structures such as tissues, organs, and arterial and venous blood flow. Skin‐mounted wearable ultrasound devices can enable long‐term continuous monitoring of patients to provide solutions to critical healthcare needs. However, stretchable ultrasound devices that are composed of ultrasonic transducers embedded in an elastomer matrix are incompatible with existing rigid acoustic matching layers, leading to reduced energy transmission and reduced imaging resolution. Here, a systematic study of soft composites with liquid metal (LM) fillers dispersed in elastomers reveals key strategies to tune the acoustic impedance of soft materials. Experiments supported by theoretical models demonstrate that the increase in acoustic impedance is primarily driven by the increase in density with negligible changes to the speed of sound through the material. By controlling the volume loading and particle size of the LM fillers, a material is created that achieves a high acoustic impedance 4.8 Mrayl, (> 440% increase over the polymer matrix) with low modulus (< 1 MPa) and high stretchability (> 100% strain). When the device is mechanically strained, a small decrease is observed in acoustic impedance (< 15%) with negligible decrease in sound transmittance and impact on attenuation for all droplet sizes. The stretchable acoustic matching layer is then integrated with a wearable ultrasound device and the ability to measure motion is demonstrated using a phantom model as is performed in Doppler ultrasound.

Occipital intracranial dural arteriovenous fistula with giant venous aneurysm and ruptured temporal arterial aneurysm with intra cerebral haemorrhage – a case report

As we all know 10% of all cerebral vascular anomalies are caused by a dural arteriovenous fistula (dAVF). While these lesions may be benign, the existence of retrograde venous drainage and cerebral venous reflux puts patients at risk of bleeding, neurological impairment, and death. Endovascular therapy is commonly utilized as the first-line treatment for dAVF. Both trans arterial and transvenous techniques are utilized to treat dAVF. The treatment strategy employed is dictated on the dAVF's angioarchitecture, location, and venous flow direction. Surgery and, to a lesser extent, stereotactic radiosurgery are used when endovascular procedures are ineffective or unsatisfactory, as well as when an AV fistula is associated with a ruptured aneurysm with cerebral bleeding.

Cerebral Blood Flow, Brain Injury, and Aortic-Pulmonary Collateral Flow After the Fontan Operation

Patients with a single ventricle develop aortopulmonary collaterals (APCs) whose flow has been shown to be inversely proportional to cerebral blood flow (CBF) in a previous cross-sectional study. Longitudinal CBF and APC flow in patients with Fontan physiology adjusting for brain injury (BI) has never been reported. Decreased CBF and BI may adversely impact neurodevelopment. A prospective longitudinal cohort of 27 patients with Fontan physiology (aged 10 ± 1.9years, 74% male) underwent cardiac and brain magnetic resonance imaging 3 to 9months and 6.0 ± 1.86years after Fontan operation to measure the CBF and APC flow and to reassess the BI (focal BI, generalized insult, and hemorrhage). CBF was measured using jugular venous flow and APC flow was measured by the difference between aortic flow and caval return. Multivariate modeling was used to assess the relation between the change in APC flow and BI. A strong inverse relation was found between CBF/aortic flow change and APC flow/aortic flow and APC flow/body surface area change (R2=0.70 and 0.72 respectively, p <0.02). Overall, the CBF decreased by 9 ± 11% and the APC flow decreased by 0.73 ± 0.67l/min/m2. The evolution of CBF and APC flow were significantly and inversely related when adjusting for time since Fontan operation, gender, and BI on the multivariate modeling. Every unit increase in APC flow change was associated with an 8% decrease in CBF change. In conclusion, CBF and APC flow change are inversely related across serial imaging, adjusting for time from Fontan operation, gender, and BI. CBF and APC aortic flow decrease over a 6-year period. This may adversely impact neurodevelopment. Because APCs can be embolized, this may be a modifiable risk factor. Clinical trials numbers: NCT02135081 and NCT02919956.

Supporting evidence for an "arterial pump" venous return mechanism in humans.

Blood flow in large veins is dependent on arterial-atrial pressure gradients and pumping mechanisms in concert with valve recruitment. Classic descriptions of muscle and respiratory pumps describe venous transmural pressure changes that cause flow. Not often considered is the transmission of pulsatile energy from arteries to veins directly adjacent to each other. Recently, an ex vivo study demonstrated a novel arterial pump effect in venoarterial bundles when valves were active in managing venous flow. We sought to show in vivo evidence of this arterial pump mechanism in 16 healthy young adults. Venous blood flow was measured in the venoarterial bundled deep femoral vein (DFV) and the greater saphenous vein (GSV), which is not bundled with an artery. Veins were studied through randomized body positions of -6° head-down tilt (HDT), supine, 20° head-up tilt (HUT), and 40° HUT, with the assumption that greater HUT postures increased valve dependence to observe the arterial pump effect. Between 20° and 40° HUT conditions, bundled DFV blood flow did not change (68 ± 36 vs. 71 ± 56 mL·min-1; Padj > 0.99), whereas nonbundled GSV blood flow decreased (6.1 ± 4.8 vs. 3.5 ± 3.9 mL·min-1; P = 0.01). Diameters between 20° and 40° HUT conditions increased in DFV (0.90 ± 0.16 vs. 1.04 ± 0.19 cm; P < 0.01), but not in GSV (0.33 ± 0.10 vs. 0.32 ± 0.08 cm; P = 0.60). These data support previous ex vivo observations that when venous pressure gradients rely on valve recruitment, presence of an adjacent artery may protect against further decreases in blood flow. The arterial pump mechanism is an underappreciated contributor to venous return and warrants further investigation.NEW & NOTEWORTHY Venous return mechanisms have classically considered muscle and respiratory pumps; however, recent ex vivo evidence suggests that pulsatile energy imparted from arteries to adjacent bundled veins can increase venous flow under certain driving pressures. We tested this concept in humans by manipulating hydrostatic pressures and measuring flow in bundled and nonbundled veins. The bundled vein exhibited flow preservation at the highest hydrostatic pressure. We suggest a novel conservation of energy mechanism within the circulatory system.

Neurosurgical implications of the Jugular Vein Nutcracker

In the last ten years, a new variant of Eagle Syndrome is emerging and being described: Styloid Jugular Nutcracker (SJN). In SJN, an elongated or vertically directed styloid process causes jugular vein stenosis by compressing the vein against the arch of C1. The clinical consequences appear to be various and misunderstood, ascribable mainly to venous flow impairment and consequent intracranial hypertension. The aim of this paper is to create an overview of Jugular Vein Nutcracker and to focus on its neurosurgical implications. A PRISMA-based literature search was performed to select the most relevant papers on the topic and to realize a mini-review. Future searches in the neurosurgical field should focus on collecting data about further causes of jugular stenosis compression and the association of SJN with cerebrovascular diseases. It would also be interesting to investigate the potential role of primary and secondary prevention, which is unknown so far.