Direction Of Blood Flow Research Articles

Imaging of human corneoscleral junction (Limbus) vasculature with 100 KHz A-scan rate swept-source optical coherence tomography/angiography (OCT/A) system

The study demonstrates in-vivo three-dimensional depth-resolved Optical Coherence Tomography Angiography (OCTA) and Doppler OCT imaging performed on the anterior segment of the human eye. A high-speed swept-source OCT system was developed utilizing a swept-source laser having a 100 kHz A-scan sweep rate and centre wavelength at 1060 nm. The proposed system has an axial resolution of 4.5 µm and a transverse imaging resolution of 14 µm. The Doppler OCT provides information regarding the direction of blood flow in corneoscleral junction vessels, which employs the Joint Spectral and Time domain OCT (STdOCT) method. Parameters influencing the imaging of various vessels, like scanning density, A-scan rate, B-scan averaging, and number of BM scanning repeats, were also studied. Slit lamp images and OCT angiography en-face projections produced from PVOCTA (Phase-variance OCTA) and STdOCTA from the same regular patients were compared in order to demonstrate the additional potential of the system. The vascular systems at the Limbus consisting of circulatory, lymphatic, and aqueous outflow systems were imaged and presented. The output clinical parameters of the system will contribute to understanding the blood circulation with directionality at the limbus location, which can be further utilized to identify glaucoma. In the author's opinion, this article represents the first attempt to provide Doppler OCTA data for the anterior chamber of the human eye.

Inversion of Asymmetric Vortex Vein Dilatation in Pachychoroid Spectrum Diseases

PurposeIntervortex venous anastomosis is widely recognized as compensating for vortex vein congestion in pachychoroid spectrum diseases. However, determining the blood flow direction within the compensated drainage route is often challenging. Herein, we investigated the morphological patterns of vortex veins in eyes showing retrograde pulsatile vortex venous flow. DesignRetrospective observational case series. Subjects689 consecutive eyes with treatment-naïve central serous chorioretinopathy, pachychoroid neovasculopathy, or polypoidal choroidal vasculopathy. MethodsWe reviewed the clinical records of patients with these pachychoroid spectrum diseases. Multimodal images including indocyanine green angiography (ICGA) and en face optical coherence tomography were analyzed. Main Outcome MeasuresIntervortex venous anastomosis between superotemporal and inferotemporal vortex veins and the dominant site of dilated temporal vortex veins were determined in the eyes with retrograde pulsatile vortex venous flow in the temporal vortex veins. Results22 eyes with retrograde pulsatile vortex venous flow in the temporal vortex veins were identified utilizing early-phase ICGA videos. In 9 eyes, retrograde pulsatile flow was detected in the superotemporal vortex veins which were connected to the inferotemporal vortex veins via intervortex venous anastomoses. Among these cases, contralateral inferotemporal vortex vein dilatation was dominant in 7 eyes (77.8%), while superotemporal and inferotemporal vortex veins were symmetrically dilated in the other 2 eyes (22.2%). On the other hand, in 13 eyes, the retrograde pulsatile flow was detected in the inferotemporal vortex veins which were linked to the superotemporal vortex veins via intervortex venous anastomoses. In these eyes, contralateral superotemporal vortex vein dilatation was dominant in 10 eyes (76.9%). Superotemporal and inferotemporal vortex veins were symmetrically dilated in 2 eyes (15.4%), while mainly inferotemporal vortex veins were dilated in 1 eye (7.7%). ConclusionsIn pachychoroid spectrum diseases, there are cases wherein congested venous blood might drain into the contralateral vortex veins via intervortex anastomoses. Overloaded contralateral vortex veins may, as a consequence, become more dilated than the primary congested vortex veins. Inversion of asymmetric vortex vein dilatation might thereby develop in pachychoroid spectrum diseases.

Analysis of the clinical characteristics of V4 segment steal blood in the vertebral artery

Objective: To explore the clinical characteristics of unilateral vertebral artery V4 segment occlusive lesions (severe stenosis or occlusion), where the contralateral vertebral artery can be compensated through blood flow and reverse supply to the posterior inferior cerebellarartery (PICA). Methods: This study is a retrospective case series of 66 patients with V4 segment occlusive lesions of unilateral vertebral artery diagnosed and treated from June 2020 to October 2022. Patient data were retrospectively collected, and their hemodynamic characteristics and imaging data were analyzed. Results: Of the 66 cases, 11 patients (16.7%) with V4 segment occlusive disease showed the blood flow of the vertebral artery on the opposite side of the lesion on the digital subtraction angiography (DSA), which can be reverse stolen to the posterior inferior cerebellar artery of the diseased side through the confluence point of the vertebrobasilar artery through the distal end of the ipsilateral vertebral artery V4. Owing to the lack of literature on this pathway and based on the characteristics of previous definitions of subclavian artery steal and carotid artery steal, we referred to this pathway as the vertebral artery V4 segment steal. In 6 patients (9.1%), transcranial Doppler ultrasound (TCD) and transcranial color Doppler ultrasound (TCCD) showed that the blood flow signal was not detected at the proximal end of the V4 segment of the affected side, rather the blood flow direction was reversed at the distal end of the V4 segment, resulting in compensatory acceleration of the blood flow velocity of the V4 segment of the contralateral vertebral artery. Conclusion: "V4 segment steal of vertebral artery" is a very rare route of vertebral artery steal. When V4 segment of the vertebral artery is occluded, clinicians should pay attention to observe the blood supply of PICA and whether there is such a steal route, to better evaluate the blood flow compensation and prognosis of patients.

Pathogenic soluble tau peptide disrupts endothelial calcium signaling and vasodilation in the brain microvasculature

The accumulation of the microtubule-associated tau protein in and around blood vessels contributes to brain microvascular dysfunction through mechanisms that are incompletely understood. Delivery of nutrients to active neurons in the brain relies on capillary calcium (Ca2+) signals to direct blood flow. The initiation and amplification of endothelial cell Ca2+ signals require an intact microtubule cytoskeleton. Since tau accumulation in endothelial cells disrupts native microtubule stability, we reasoned that tau-induced microtubule destabilization would impair endothelial Ca2+ signaling. We tested the hypothesis that tau disrupts the regulation of local cerebral blood flow by reducing endothelial cell Ca2+ signals and endothelial-dependent vasodilation. We used a pathogenic soluble tau peptide (T-peptide) model of tau aggregation and mice with genetically encoded endothelial Ca2+ sensors to measure cerebrovascular endothelial responses to tau exposure. T-peptide significantly attenuated endothelial Ca2+ activity and cortical capillary blood flow in vivo. Further, T-peptide application constricted pressurized cerebral arteries and inhibited endothelium-dependent vasodilation. This study demonstrates that pathogenic tau alters cerebrovascular function through direct attenuation of endothelial Ca2+ signaling and endothelium-dependent vasodilation.

Endothelialization of PTFE-covered stents for aneurysms and arteriovenous fistulas created in canine carotid arteries

To investigate the endothelialization of covered and bare stents deployed in the canine carotid arteries and subclavian arteries for treating experimental aneurysms and arteriovenous fistulas, twenty aneurysms were created in 10 dogs, and 20 fistulas in another 10 dogs. The Willis balloon-expandable covered stent and a self-expandable covered stent were used to treat these lesions, and a self-expandable bare stent was deployed in the subclavian artery for comparison. Followed up for up to 12 months, the gross observation, pathological staining, and scanning electronic microscopic data were analyzed. Two weeks after creation of animal model, thirty self-expandable covered stents and ten balloon-expandable covered stents were deployed. Fifteen bare stents were deployed within the left subclavian arteries. Twenty days after stenting, the aneurysm significantly shrank. At 6 months, the thrombi within the aneurysm cavity were organized. Three to 12 months later, most covered and bare stents were covered by a thin transparent or white layer of endothelial intima. Layers of intima or pseudomembrane were formed on the stent 20–40 days after stent deployment. Over three months, the pseudomembrane became organized, thinner, and merged into the vascular wall. Under scanning electronic microscopy, the surface of covered and bare stents had only deposition of collagen fibers and rare endothelial cells 20–40 days after stenting. From three to ten months, the endothelial cells on the internal surface of stent became mature, with spindle, stripe-like or quasi round morphology along the blood flow direction. Over time, the endothelial cells became mature. In conclusion, three months after deployment in canines’ arteries, the self-expandable bare and covered stents have mostly been covered by endothelial cells which become maturer over time, whereas the balloon-expandable covered stents do not have complete coverage of endothelial cells at three months, especially for protruding stent struts and areas. Over time, the endothelialization will become mature.

Increasing the sensor channels: a solution for the pressing offsets that cause the physiological parameter inaccuracy in radial artery pulse signal acquisition.

Introduction: In studies of pulse wave analysis, single-channel sensors only adopt single temporal pulse signals without spatial information to show pulse-feeling patterns. Multi-channel arterial pulse signals, also named as three-dimensional pulse images (3DPIs), provide the spatial and temporal characteristics of radial pulse signals. When involving single or few-channel sensors, pressing offsets have substantial impacts on obtaining inaccurate physiological parameters like tidal peak (P2). Methods: This study discovers the pressing offsets in multi-channel pulse signals and analyzes the relationship between the pressing offsets and time of P2 (T2) by qualifying the pressing offsets. First, we employ a data acquisition system to capture 3DPIs. Subsequently, the errorT2 is developed to qualify the pressing offsets. Results: The outcomes display a central low and peripheral high pattern. Additionally, the errorT2 increase as the distances from the artery increase, particularly at the radial ends of the blood flow direction. For every 1mm increase in distances between sensing elements and center sensing elements, the errorT2 in the radial direction escalates by 4.87%. When the distance is greater than 3.42mm, the errorT2 experiences a sudden increase. Discussion: The results show that increasing the sensor channels can overcome the pressing offsets in radial pulse signal acquisition.

Angiosome-Targeted Infrapopliteal Angioplasty: Impact on Clinical Outcomes—An Observational Study

Background: Revascularization based on the angiosome concept (AC) is a controversial subject because there is currently no clear evidence of its efficacy, due to the heterogeneity of patients (multiple and diverse risk factors and comorbidities, multiple variations in the affected angiosomes). Choke vessels change the paradigm of the AC, and the presence or absence of the plantar arch directly affects the course of targeted revascularization. The aim of this study was to evaluate the effect of revascularization based on the AC in diabetic patients with chronic limb-threatening ischemia (CLTI). Methods: This retrospective analysis included 51 patients (40 men, 11 women), with a mean age of 69 years (66–72) and a total of 51 limbs, who presented with Rutherford 5–6 CLTI, before and after having undergone a drug-coated balloon angioplasty (8 patients) or plain balloon angioplasty (43). Between November 2018 and November 2019, all patients underwent below-the-knee balloon angioplasties and were followed up for an average of 12 months. The alteration of microcirculation was compared between directly and indirectly revascularized angiosomes. The study assessed clinical findings and patient outcomes, with follow-up investigations, comparing wound healing rates between the different revascularization methods. Patient records and periprocedural leg digital subtraction angiographies (DSA) were analyzed. Differences in outcomes after direct revascularization and indirect percutaneous transluminal angioplasty (PTa) were examined using Cox proportional hazards analysis, with the following endpoints: ulcer healing, limb salvage, and also amputation-free survival. Results: Direct blood flow to the angiosome supplying the ulcer area was achieved in 38 legs, in contrast to 13 legs with indirect revascularization. Among the cases, there were 39 lesions in the anterior tibial artery (ATA), 42 lesions in the posterior tibial artery (PTA), and 8 lesions in the peroneal artery (PA). According to a Cox proportional hazards analysis, having fewer than three (<3) affected angiosomes (HR 0.49, 95% CI 0.19–1.25, p = 0.136) was associated with improved wound healing. Conversely, wound healing outcomes were least favorable after indirect angioplasty (p = 0.206). When adjusting the Cox proportional hazard analysis for the number of affected angiosomes, it was found that direct drug-coated angioplasty resulted in the most favorable wound healing (p = 0.091). At the 1-year follow-up, the major amputation rate was 17.7%, and, according to a Cox proportional hazards analysis, atrial fibrillation (HR 0.85, 95% CI 0.42–1.69, p = 0.637), hemodialysis (HR 1.26, 95% CI 0.39–4.04, p = 0.699), and number of affected angiosomes > 3 (HR 0.94, 95% CI 0.63–1.39, p = 0.748) were significantly associated with poor leg salvage. Additionally, direct endovascular revascularization was associated with a lower rate of major amputation compared to indirect angioplasty (HR 1.09, 95% CI 0.34–3.50, p = 0.884). Conclusions: Observing the angiosomes concept in decision-making appears to result in improved rates of arterial ulcer healing and leg salvage, particularly in targeted drug-coated balloon angioplasty for diabetic critical limb ischemia, where multiple angiosomes are typically affected.

Assessment of Pulmonary Circulation of Critically Ill Patients Based on Critical Care Ultrasound

Pulmonary circulation is crucial in the human circulatory system, facilitating the oxygenation of blood as it moves from the right heart to the lungs and then to the left heart. However, during critical illness, pulmonary microcirculation can be vulnerable to both intrapulmonary and extrapulmonary injuries. To assess these potential injuries in critically ill patients, critical point-of-care ultrasound can be used to quantitatively and qualitatively evaluate the right atrium, right ventricle, pulmonary artery, lung, pulmonary vein, and left atrium along the direction of blood flow. This assessment is particularly valuable for common ICU diseases such as acute respiratory distress syndrome (ARDS), sepsis, pulmonary hypertension, and cardiogenic pulmonary edema. It has significant potential for diagnosing and treating these conditions in critical care medicine.

Underestimation of Flow Velocity in 2-D Super-Resolution Ultrasound Imaging.

Velocity estimation in ultrasound imaging is a technique to measure the speed and direction of blood flow. The flow velocity in small blood vessels, i.e., arterioles, venules, and capillaries, can be estimated using super-resolution ultrasound imaging (SRUS). However, the vessel width in SRUS is relatively small compared with the full-width-half-maximum of the ultrasound beam in the elevation direction (FWHMy), which directly impacts the velocity estimation. By taking into consideration the small vessel widths in SRUS, it is hypothesized that the velocity is underestimated in 2-D super-resolution ultrasound imaging when the vessel diameter is smaller than the FWHMy. A theoretical model is introduced to show that the velocity of a 3-D parabolic velocity profile is underestimated by up to 33% in 2-D SRUS, if the width of the vessel is smaller than the FWHMy. This model was tested using Field II simulations and 3-D printed micro-flow hydrogel phantom measurements. A Verasonics Vantage 256™ scanner and a GE L8-18i-D linear array transducer with FWHMy of approximately 770 μm at the elevation focus were used in the simulations and measurements. Simulations of different parabolic velocity profiles showed that the velocity underestimation was 36.8%±1.5% (mean±standard deviation). The measurements showed that the velocity was underestimated by 30%±6.9%. Moreover, the results of vessel diameters, ranging from 0.125×FWHMy to 3×FWHMy, indicate that velocities are estimated according to the theoretical model. The theoretical model can, therefore, be used for the compensation of velocity estimates under these circumstances.

Spiral groove bearing design for improving plasma skimming in rotary blood pumps

High-efficiency plasma skimming is hopeful to prevent hemolysis inside spiral groove bearings (SGBs) because it can exclude red blood cells from the ridge gap with a high shear force. However, no study reveals the shape design of SGBs to improve plasma skimming. Therefore, this study proposed and applied a groove design strategy to designing an optimal SGB for enhancing plasma skimming in a rotary blood pump (RBP). Initially, we proposed the design strategy that the shape of the groove for enhancing plasma skimming corresponds to the direction of blood flow in the ridge gap. Second, we visualized the cell flow in a specially designed experimental RBP to determine the direction of blood flow, which was helpful in the subsequent SGB design. Then, we created an SGB to provide superior plasma skimming and applied it to the experimental RBP. We evaluated the plasma skimming effect of SGB at rotational speeds ranging from 2400 to 3000 rpm and hematocrit conditions between 1% and 40%. At a 1% hematocrit, the plasma skimming efficiency for the entire SGB was greater than 95%. In all hematocrit conditions, the efficiency at the inner ridges of the SGB was greater than 80%. The results showed the designed SGB successfully induced excellent plasma skimming within ridge gaps. This study is the first to propose and apply a shape design strategy to generate excellent plasma skimming within an SGB. This study may contribute to the prevention of SGB hemolysis inside SGB for use in RBPs.

The Safety and Efficacy of Leo Stents with Coiling or Alone for Anterior Cerebral Artery Aneurysms.

Treatment of anterior cerebral artery (ACA) aneurysms is still not well established. The Leo stent with blood flow direction is a retrievable stent for intracranial aneurysms, whereas it needs to be studied clearly in patients with ACA aneurysms. Consecutive patients with ACA aneurysms were retrospectively enrolled in three neurosurgical centers between January 2016 and October 2021. The data on demographics, aneurysm characteristics, symptom resolution, and postoperative course were collected and analyzed. The aneurysm occlusion status was appraised by Raymond-Ray Occlusion Class (RROC). A total of 57 patients with ACA aneurysms were included in our study. Immediate postprocedural angiograms showed that 20 aneurysms (35.1%) were in complete occlusion (RROC 1), 26 aneurysms (45.6%) were in near-complete occlusion (RROC 2), 11 aneurysms (19.3%) were in incomplete occlusion (RROC 3). The angiographic follow-up found that the rate of complete occlusion increased to 57.9%, and near-completion and incomplete occlusion dropped to 29.8% and 12.3%, respectively. The angiographic result of the last follow-up improved significantly (Z=- 2.805, P=0.005). Univariate analysis indicated that distal location of aneurysms (Z=4.538, P=0.033) and ruptured aneurysms (χ2=.6120, P=0.032) were potential risk factors for intra-parent artery narrowing. Furthermore, multivariate logistic regression analysis found that A3 aneurysms (95% CI 1.427~32.744, P=0.016) are the key risk factor for intra-parent artery narrowing. The Leo stent is safe and effective for aneurysms located in ACA circulations. The overall occlusion degree improved during follow-up. A distal, small artery was the risk factor for intra-parent artery narrowing.

Comparison of aortic blood flow rotational direction in healthy volunteers and patients with bicuspid aortic valves using volumetric velocity-sensitive cardiovascular magnetic resonance imaging.

The rotational direction (RD) of helical blood flow can be classified as either a clockwise (RD+) or counter-clockwise (RD-) flow. We hypothesized that this simple classification might not be sufficient for analysis in vivo and a simultaneous existence of RD+/- may occur. We utilized volumetric velocity-sensitive cardiovascular magnetic resonance imaging (4D flow MRI) to analyze rotational blood flow in the thoracic aorta. Forty volunteers (22 females; mean age, 41±16 years) and seventeen patients with bicuspid aortic valves (BAVs) (9 females; mean age, 42±14 years) were prospectively included. The RDs and the calculation of the rotating blood volumes (RBVs) in the thoracic aorta were performed using a pathline-projection strategy. We could confirm a mainly clockwise RD in the ascending, descending aorta and in the aortic arch. Furthermore, we found a simultaneous existence of RD+/RD-. The RD+/--volume in the ascending aorta was significantly higher in BAV patients, the mean RD+/RD- percentage was approximately 80%/20% vs. 60%/40% in volunteers (P<0.01). The maximum RBV always occurred during systole. There was significantly more clockwise than counter-clockwise rotational flow in the ascending aorta (P<0.01) and the aortic arch (P<0.01), but no significant differences in the descending aorta (P=0.48). A simultaneous occurrence of RD+/RD- indicates that a simple categorization in either of both is insufficient to describe blood flow in vivo. Rotational flow in the ascending aorta and in the aortic arch differs significantly from flow in the descending aorta. BAV patients show significantly more clockwise rotating volume in the ascending aorta compared to healthy volunteers.

Photoacoustic vector tomography for deep haemodynamic imaging.

Imaging deep haemodynamics non-invasively remains a quest. Although optical imaging techniques can be used to measure blood flow, they are generally limited to imaging within ∼1 mm below the skin's surface. Here we show that such optical diffusion limit can be broken through by leveraging the spatial heterogeneity of blood and its photoacoustic contrast. Specifically, successive single-shot wide-field photoacoustic images of blood vessels can be used to visualize the frame-to-frame propagation of blood and to estimate blood flow speed and direction pixel-wise. The method, which we named photoacoustic vector tomography (PAVT), allows for the quantification of haemodynamics in veins more than 5 mm deep, as we show for regions in the hands and arms of healthy volunteers. PAVT may offer advantages for the diagnosis and monitoring of vascular diseases and for the mapping of the function of the circulatory system.

Assessment of Collateral Pathways in Carotid Occlusion: Investigating the Clinical Significance of Ultrasound and TCCS

Background: Carotid occlusion is a severe condition closely associated with ischemic stroke. The prompt identification of patients presenting with extracranial carotid artery occlusion and the evaluation of collateral circulation compensation in these individuals bear significant clinical importance for subsequent patient management. Ultrasound offers significant advantages in the diagnosis of extracranial carotid artery stenosis and occlusion, while Transcranial Color-Coded Sonography (TCCS) is increasingly pivotal in assessing intracranial artery stenosis and determining blood flow direction. The objective of our study was to assess the concordance between ultrasound combined with TCCS and digital subtraction angiography (DSA) in evaluating extracranial carotid occlusion and intracranial collateral circulation.&#x0D; Methods: Patients with severe stenosis in the extracranial carotid artery were recruited for our study. All patients suspected of having occlusion in the extracranial carotid arteries underwent ultrasound, transcranial color-coded sonography (TCCS), and digital subtraction angiography (DSA). Sensitivity, specificity, positive predictive value, negative predictive value, overall accuracy, and kappa value were employed to assess the effectiveness and consistency of ultrasound and TCCS compared to DSA.&#x0D; Results: Ultrasound demonstrated a sensitivity of 85.4%, specificity of 100%, positive predictive value of 100%, negative predictive value of 90.4%, and overall accuracy of 93.9% in the diagnosis of extracranial artery occlusion. The kappa value was calculated as 0.87 (P＜0.001), indicating substantial agreement between ultrasound and DSA measurements for consistency assessment. Transcranial color-coded sonography (TCCS) exhibited a sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy of 97.6%, 100%, 100%, 66.7%, and 97.7% respectively in evaluating collateral circulation in patients with carotid artery occlusion. The kappa value was 0.79 (P＜0.001) in assessing the collateral circulation in patients with occluded carotid arteries.&#x0D; Conclusions: Ultrasound proved to be a valuable tool for evaluating patients with occluded carotid arteries, while TCCS emerged as a reliable approach for assessing collateral pathways in individuals with extracranial carotid artery occlusion.

Abstract 14878: Be Aware of False Negative Bubble Study in Diagnosis of Patent Foramen Ovale!

Introduction: Echocardiography plays an important role in diagnosis of Patent Foramen Ovale (PFO). However, there are some anatomic variations which may result in a false negative study. Case presentation: A 55-year-old male was hospitalized for acute right-hemiplegia. The EKG revealed normal sinus rhythm. Brain imaging revealed acute bilateral infarcts. The transthoracic echocardiogram (TTE) showed a normal ejection fraction without significant valve disease and a negative agitated saline Bubble study. A Trans-esophageal echocardiogram (TEE) revealed a negative Bubble study using intravenous access via the left arm. The TEE also revealed an atrial septal aneurysm and large eustachian valve (EV). The Bubble study was then repeated with agitated saline injected from lower extremity. This demonstrated a significant right to left shunt through a PFO. Discussion: EV is a remnant of the valve of the inferior vena cava that directs blood flow through the fossa ovalis during embryonic life. A large or prominent EV may be a risk factor for paradoxical embolism by preventing spontaneous foramen closure. Agitated saline originating from the superior vena cava (SVC) may result in a false-negative study due to the prominent EV preventing microbubbles from the SVC from crossing the interatrial septum. In this case, the patient’s age, clinical presentation and the finding of EV and atrial septal aneurysm raised the suspicion of PFO. Repeating the bubble study using a lower extremity peripheral access was positive. This step played a crucial role in the diagnosis of PFO in this patient and his subsequent management. Conclusion: Cardiologists should be aware that the presence of a prominent EV may result in a false negative bubble study result when the injection is performed via upper limb intravenous access.

Abstract 148: Balloon‐assisted retrograde Cerebral Venography in Cerebral Venous Interventions: A novel avenue for diagnostic venous imaging

Introduction Angiographic imaging of cerebral venous system is derived from the delayed phase of a cerebral arteriogram. The venous phase of arteriogram provides washed out images, quality of which is determined by the direction of dominant venous outflow, iodinated contrast ratio and flat panel imaging resolution*. Direct venous injections are limited in visualization due to injections against the direction of blood flow. We identified a method of cerebral phlebography under temporary venous balloon occlusion of jugular vein or venous sinus to obtain high resolution 2D and 3D images for diagnosis and treatment of cerebral venous pathology. We propose the addition and use of large diameter compliant balloon guide catheters in the workflow of cerebral venous imaging to optimize filling of cerebral venous system and significantly improve venous imaging. Methods A case series of 15 patients who underwent Intracranial Venous Interventions were collected from the Hospital of the University of Pennsylvania. All patients underwent 2 and 3‐dimensional retrograde phlebography assisted by temporary inflation of balloon guide catheter. Results 9 females and 6 males received venous access predominantly located in right cubital fossa in the cephalic or basilic vein using an 8 and 9 french sheaths. The balloon guide catheters employed included Walrus Balloon Guide 8F (Q’apel medical) 8 cases, Dr Banner Balloon Guide ( EO solutions corp) 5 cases, Bobby Balloon guide (microvention)1 case, Emboguard Balloon Guide ( Cerenovus) 1 case. Utilization of balloon catheters resulted in minimal increase in average procedure time with improved filling and depiction of venous vessels, and no complications. Conclusion Balloon assisted retrograde phlebography using compliant balloon guide catheters is an effective way to image cerebral veins while decreasing the difficulty associated with working against the flow of venous blood.

4-Axis 3D-Printed Tubular Biomaterials Imitating the Anisotropic Nanofiber Orientation of Porcine Aortae.

Many of the peculiar properties of the vasculature are related to the arrangement of anisotropic proteinaceous fibers in vessel walls. Understanding and imitating these arrangements can potentially lead to new therapies for cardiovascular diseases. These can be pre-surgical planning, for which patient-specific ex vivo anatomical models for endograft testing are of interest. Alternatively, therapies can be based on tissue engineering, for which degradable in vitro cell growth substrates are used to culture replacement parts. In both cases, materials are desirable that imitate the biophysical properties of vessels, including their tubular shapes and compliance. This work contributes to these demands by offering methods for the manufacturing of anisotropic 3D-printed nanofibrous tubular structures that have similar biophysical properties as porcine aortae, that are biocompatible, and that allow for controlled nutrient diffusion. Tubes of various sizes with axial, radial, or alternating nanofiber orientation along the blood flow direction are manufactured by a customized method. Blood pressure-resistant, compliant, stable, and cell culture-compatible structures are obtained, that can be degraded in vitro on demand. It is suggested that these healthcare materials can contribute to the next generation of cardiovascular therapies of ex vivo pre-surgical planning or in vitro cell culture.

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.

Pentadecapeptide BPC 157 as Therapy for Inferior Caval Vein Embolization: Recovery of Sodium Laurate-Post-Embolization Syndrome in Rats.

After inferior caval vein embolization therapy, post-embolization syndrome (sodium laurate 10 mg/kg, 0.1 mL into rat inferior caval vein, assessment at 15, 30, 60 min, prime lung lesions, thromboemboli occluding lung vessels), as a severe occlusion/occlusion-like syndrome, might be resolved as a whole by stable gastric pentadecapeptide BPC 157 therapy. At 5 min after laurate injection, stable gastric pentadecapeptide BPC 157 was implemented as therapy (10 µg/kg, 10 ng/kg intraperitoneally or intragastrically). As before, confronted with the occlusion of major vessel(s) or similar noxious procedures, such as rapidly acting Virchow triad circumstances, the particular effect of the therapy (i.e., collateral pathways activation, "bypassing vascular key", i.e., direct blood flow delivery via activation of azygos vein) assisted in the recovery of the vessel/s and counteracted multiorgan failure due to occlusion/occlusion-like syndrome as a whole in the laurate-injected rats. Along with prime lung lesions and thromboemboli occluding lung vessels, post-embolization syndrome rapidly occurred peripherally and centrally as a shared multiorgan and vessel failure, brain, heart, lung, liver, kidney, and gastrointestinal tract lesions, venous hypertension (intracranial (superior sagittal sinus), portal, and caval), aortal hypotension, progressing thrombosis in veins and arteries and stasis, congested and/or failed major veins, and severe ECG disturbances. Whatever the cause, these were all counteracted, eliminated, or attenuated by the application of BPC 157 therapy. As recovery with BPC 157 therapy commonly and rapidly occurred, reversing the collapsed azygos vein to the rescuing collateral pathway might initiate rapid direct blood delivery and start blood flow reorganization. In conclusion, we suggest BPC 157 therapy to resolve further vascular and embolization injuries.

The Impact of Left Ventricular Assist Device Outflow Graft Positioning on Aortic Hemodynamics: Improving Flow Dynamics to Mitigate Aortic Insufficiency.

Heart failure is a global health concern with significant implications for healthcare systems. Left ventricular assist devices (LVADs) provide mechanical support for patients with severe heart failure. However, the placement of the LVAD outflow graft within the aorta has substantial implications for hemodynamics and can lead to aortic insufficiency during long-term support. This study employs computational fluid dynamics (CFD) simulations to investigate the impact of different LVAD outflow graft locations on aortic hemodynamics. The introduction of valve morphology within the aorta geometry allows for a more detailed analysis of hemodynamics at the aortic root. The results demonstrate that the formation of vortex rings and subsequent vortices during the high-velocity jet flow from the graft interacted with the aortic wall. Time-averaged wall shear stress (TAWSS) and oscillatory shear index (OSI) indicate that modification of the outflow graft location changes mechanical states within the aortic wall and aortic valve. Among the studied geometric factors, both the height and inclination angle of the LVAD outflow graft are important in controlling retrograde flow to the aortic root, while the azimuthal angle primarily determines the rotational direction of blood flow in the aortic arch. Thus, precise positioning of the LVAD outflow graft emerges as a critical factor in optimizing patient outcomes by improving the hemodynamic environment.