Vessel Tortuosity Research Articles

Feasibility and Safety of Double-Wire Technique for Microcatheter Navigation Beyond Tortuous Internal Carotid Siphon: A Propensity Score-Matched Study.

Severe vessel tortuosity may prevent a microcatheter from reaching a distal vessel. However, the double-wire technique (DWT) may facilitate the procedure. The present study evaluated the feasibility and safety of guiding a 0.027-inch microcatheter into a distal vessel beyond the tortuous internal carotid siphon (ICS) using the DWT. We retrospectively reviewed 61 consecutive unruptured anterior circulation aneurysms in 61 patients who underwent treatment using flow diverter or intrasaccular flow disruption with a 0.027-inch microcatheter at our institution between October 2021 and August 2024. The DWT was used for patients in whom difficulties were encountered in advancing the microcatheter beyond the ICS with a single wire. Patients were divided into 2 groups, those who required the DWT (DWT group) and those who did not (non-DWT group). To investigate whether DWT use was associated with the degree of tortuosity of the ICS, a propensity score-matched analysis was used to control for background factors. Ultimately, 11 (18.0%) used DWT to guide a 0.027-inch microcatheter into the distal vessel of the ICS, achieving 100% success rate. After matching, the radius of ICS was significantly smaller in the DWT group than in the non-DWT group (2.7 mm vs. 3.7 mm, P= 0.039). No significant difference in the complication rate was found between the 2 groups. Although a 0.027-inch microcatheter is difficult to guide beyond a tortuous ICS to a distal internal carotid artery using only a single wire, the application of the DWT may allow the catheter to be guided without increased complications.

Normalization of tumor vasculature by imiquimod: proposal for a new anticancer therapeutic indication for a TLR7 agonist

Imiquimod (IMQ), a drug from aminoquinoline group, is the toll-like receptor 7 (TLR7) agonist. It acts as an immunostimulant and radio-sensitizing agent. IMQ stimulates both innate and adaptive immune response. Despite studies conducted, there are no unambiguous data showing how IMQ affects the condition of tumor blood vessels. Tumor vasculature plays the main role in tumor progression. Formation of abnormal blood vessels increases area of hypoxia which recruits suppressor cells, blocks tumor infiltration by CD8+ T lymphocytes, inhibits efficacy of chemoterapeutic drug and leads to cancer relapse. Normalization is a type of therapy targeted at abnormal tumor blood vessels. Here, we demonstrated that 50 µg of IMQ inhibits the growth of melanoma tumors more efficiently, compared to other tested doses and the control group. Dose escalation did not improve the therapeutic antitumor potential of TLR7 agonist. A dose of 50 µg of IMQ most effectively reduced tumor blood vessel density. Imiquimod normalized tumor vasculature both structurally (by reducing vessel tortuosity and increasing pericyte coverage) and functionally (by improving tumor perfusion) in a dose-dependent manner. Hypoxia regions in tumors of treated mice were significantly reduced after IMQ administration. A dose of 50 µg of IMQ had also the greatest impact on the changes in tumor-infiltrating T lymphocytes levels. TLR7 agonist inhibited angiogenesis in treated mice. Functional vascular normalization by IMQ increases the effectiveness of low dose of doxorubicin. Higher dose of IMQ showed worse effects than lower doses including decreased tumor perfusion, increased tumor hypoxia and immunosuppression. This knowledge may help to optimize the combination of the selected IMQ dose with e.g. chemotherapy or radiotherapy to elicit synergistic effect in cancer treatment. To conclude, we outline IMQ repurposing as a vascular normalizing agent. Our research results may contribute to expanding the therapeutic indications for the use of IMQ in anticancer therapy in the future.

Sensitivity of coronary hemodynamics to vascular structure variations in health and disease

Local hemodynamics play an essential role in the initiation and progression of coronary artery disease. While vascular geometry alters local hemodynamics, the relationship between vascular structure and hemodynamics is poorly understood. Previous computational fluid dynamics (CFD) studies have explored how anatomy influences plaque-promoting hemodynamics. For example, areas exposed to low wall shear stress (ALWSS) can indicate regions of plaque growth. However, small sample sizes, idealized geometries, and simplified boundary conditions have limited their scope. We generated 230 synthetic models of left coronary arteries and simulated coronary hemodynamics with physiologically realistic boundary conditions. We measured the sensitivity of hemodynamic metrics to changes in bifurcation angles, positions, diameter ratios, tortuosity, and plaque topology. Our results suggest that the diameter ratio between left coronary branches plays a substantial role in generating adverse hemodynamic phenotypes and can amplify the effect of other geometric features such as bifurcation position and angle, and vessel tortuosity. Introducing mild plaque in the models did not change correlations between structure and hemodynamics. However, certain vascular structures can induce ALWSS at the trailing edge of the plaque. Our analysis demonstrates that coronary artery vascular structure can provide key insight into the hemodynamic environments conducive to plaque formation and growth.

Can fundus features tell us something about 3D eye shape?

To determine whether imaging features derived from fundus photographs contain 3D eye shape information beyond that available from spherical equivalent refraction (SER). We analysed 99 eyes of 68 normal adults in the UK Biobank. An ellipsoid was fitted to the entire volume of each posterior eye (vitreous chamber without the lens)-segmented from magnetic resonance imaging of the brain. Asphericity was computed based on the semidiameters of the ellipsoid's axes to describe posterior eye shape along the horizontal (temporal-nasal) and vertical (superior-inferior) meridians, while volume was calculated as the total number of foreground voxels. Mixed-effects linear regression models were used to test the association of SER with asphericity and volume, controlling for age and sex. Then, the association between various fundus features and asphericity was tested-both before and after controlling for SER, age and sex. Posterior eyes were generally oblate (asphericity > 0), but the degree of oblateness reduced as SER decreased, with the shape tending towards prolateness in high myopia. Neither sex nor age influenced asphericity. However, males had larger posterior eyes on average (this difference disappeared after height was additionally controlled for). Optic disc (OD) orientation, OD-fovea angle, vessel tortuosity, vessel fractal dimension and central retinal arteriolar or venular equivalent (CRAE or CRVE) showed significant univariable associations with asphericity along at least one meridian. After controlling for SER, age and sex, a more negative OD-fovea angle (larger OD-fovea angular separation) remained significantly associated with reduced horizontal oblateness (p = 0.01). Similarly, decreasing CRAE (narrower arterioles) remained significantly associated with reduced oblateness along both the horizontal (p = 0.04) and vertical (p < 0.01) meridians. Variations in OD-fovea angle and CRAE are associated with differences in ocular asphericity-even in eyes with similar SER-suggesting that fundus imaging provides eye shape information beyond what is available from refractive error alone.

Noninvasive Anemia Detection and Hemoglobin Estimation from Retinal Images Using Deep Learning: A Scalable Solution for Resource-Limited Settings.

The purpose of this study was to develop and validate a deep-learning model for noninvasive anemia detection, hemoglobin (Hb) level estimation, and identification of anemia-related retinal features using fundus images. The dataset included 2265 participants aged 40years and above from a population-based study in South India. The dataset included ocular and systemic clinical parameters, dilated retinal fundus images, and hematological data such as complete blood counts and Hb concentration levels. Eighty percent of the dataset was used for algorithm development and 20% for validation. A deep-convolutional neural network, utilizing VGG16, ResNet50, and InceptionV3 architectures, was trained to predict anemia and estimate Hb levels. Sensitivity, specificity, and accuracy were calculated, and receiver operating characteristic (ROC) curves were generated for comparison with clinical anemia data. GradCAM saliency maps highlighted regions linked to anemia and image processing techniques to quantify anemia-related features. For predicting anemia, the InceptionV3 model demonstrated the best performance, achieving 98% accuracy, 99% sensitivity, 97% specificity, and an area under the curve (AUC) of 0.98 (95% confidence interval [CI] = 0.97-0.99). For estimating Hb levels, the mean absolute error for the InceptionV3 model was 0.58 g/dL (95% CI = 0.57-0.59 g/dL). The model focused on the area around the optic disc and the neighboring retinal vessels, revealing that anemic subjects exhibited significantly increased vessel tortuosity and reduced vessel density (P < 0.001), with variable effects on vessel thickness. The InceptionV3 model accurately predicted anemia and Hb levels, highlighting the potential of deep learning and vessel analysis for noninvasive anemia detection. The proposed method offers the possibility to quantitatively predict hematological parameters in a noninvasive manner.

Measuring arterial tortuosity in the cerebrovascular system using Time-of-Flight MRI.

The Circle of Willis (CW) is a critical cerebrovascular structure that supports collateral blood flow to maintain brain perfusion and compensate for eventual occlusions. Increased tortuosity of high-risk vessels within the CW has been implicated as a marker in the progression of cerebrovascular diseases especially in structures like the internal carotid artery (ICA). This is partly due to age-related plaque deposition or arterial stiffening. Producing reliable tortuosity measurements for vessels segmented from magnetic resonance (MR) time-of-flight (TOF) images requires precise curvature estimation, but existent methods struggle with noisy or sparse segmentation data. We introduce an open-source, end-to-end pipeline that uses unit-speed spline fitting for accurate curvature estimation, generating robust curvature-based tortuosity metrics for the ICA combined with an indicator of spline fit quality. We test this with theoretical data and apply this method to TOF data from 22 participants. We report that our metrics are able to capture tortuosity even under heightened noise constraints and discriminate different types of abnormal arterial coiling. We found that our ICA tortuosity measures correlate positively with age and ultrasound measured carotid artery intima media thickness. This ultimately has important translational implications for being able to reliably generate TOF tortuosity measures and estimate cerebrovascular disease burden. We provide open-source code in a GitHub repository.

Hepatic artery stenting with Viabahn

BackgroundThe effect of vessel morphology on the technical success and patency of Viabahn stent-grafts in treating postoperative arterial injuries and bleeding (AIB) after hepatopancreatobiliary surgery is not well understood. Difficulties in stent insertion persist despite using stiff guidewires to straighten tortuous vessels. This study aimed to identify vessel morphologies linked to technical success and short-term patency and to explore effective management strategies.Materials and methodsThis retrospective study examined 12 consecutive cases of hepatic artery stenting in 11 patients, using Viabahn grafts for postoperative AIB from 2017 to 2024. Patient data, angiographic outcomes, and stent placement details were reviewed. Different types of guidewires, including stiff and soft guidewires, were utilized to facilitate stent deployment. Vessel tortuosity and vessel narrowing before stent placement were evaluated both qualitatively and quantitatively. Outcomes measured included technical and clinical success rates, stent patency at one month, and the time from surgery to stent placement.ResultsFinal technical and clinical success was achieved in all cases (100%). Vessel tortuosity often led to the emergence of accordion-like appearances upon vessel straightening, necessitating additional technical adaptations due to the formation of steps (p = 0.005). One-month stent patency was observed in 10/12 cases (83%). Among cases with severe vessel narrowing distal to the bleeding point, 2/3 (67%) experienced stent occlusion, significantly higher than those with less severe narrowing (p = 0.045). All occluded cases involved the extension of stent length by overlapping stent-grafts.ConclusionsSteps created by the accordion-like appearance in the hepatic artery resulting from the straightening of tortuous vessels can complicate stent insertion, and severe narrowing distal to the bleeding point increases the risk of short-term occlusion.

Association of Proximal Vessel Tortuosity with Technical Success and Clinical Outcomes: Analysis From the Progress-CTO Registry.

Proximal vessel tortuosity can hinder wiring and equipment delivery during chronic total occlusion (CTO) percutaneous coronary intervention (PCI). We sought to examine the association of proximal vessel tortuosity with the short and long-term outcomes of patients undergoing CTO PCI. We examined the association of proximal vessel tortuosity with clinical outcomes in patients who underwent CTO PCI at 50 US and non-US centers between 2012 and 2024. Of 14,141 patients, 3,974 (28.1%) had moderate or severe proximal vessel tortuosity. Patients with moderate or severe proximal vessel tortuosity had more comorbidities and more complex angiographic characteristics, such as longer lesion length and higher prevalence of side branch at the proximal cap. Lesions with moderate or severe proximal tortuosity required greater procedure and fluoroscopy time. On unadjusted analyses, moderate/severe proximal vessel tortuosity was associated with lower technical success and higher incidence of major adverse cardiac events (MACE). In multivariable analysis, moderate/severe proximal vessel tortuosity was associated with lower technical success (odds ratio [OR]: 0.77; 95% confidence intervals [CI]: 0.67, 0.89) but similar MACE (OR: 1.26; 95% CI: 0.91, 1.73). Higher operator volume (≥ 30 CTO PCI cases per year) was associated with higher technical (85.2% vs. 75.6%, p < 0.001) and procedural success (83.6% vs. 74.5%, p < 0.001) but also higher risk of perforation (6.49% vs. 3.57%, p < 0.001) but not pericardiocentesis, in lesions with moderate/severe proximal vessel tortuosity. Moderate or severe proximal vessel tortuosity is independently associated with lower technical success in CTO PCI but not with MACE. High-volume operators are more likely to successfully perform CTO PCI in lesions with moderate/severe tortuosity at the cost of higher risk of perforation, without higher MACE.

Ultra‐widefield retinal and choroidal vascular architecture in mild cognitive impairment and normal cognition

AbstractBackgroundMild cognitive impairment (MCI) is currently a clinical diagnosis characterized by decline in memory and daily cognitive function from baseline. Exploratory studies using optical coherence tomography angiography have reported alterations in the retinal capillary plexus vessel density and attenuation of the retinal nerve fiber layer, but these results appear to be mixed. We used ultra‐widefield (UWF) imaging to evaluate retinal and choroidal vasculature and structure in individuals with mild cognitive impairment (MCI) compared to controls with normal cognition.MethodA cross‐sectional comparison of patients with MCI compared to cognitively normal controls. Scanning laser ophthalmoscopy (SLO) (California, Optos Inc, Marlborough, MA) was used to obtain UWF fundus color images. Images were analyzed with the Vasculature Assessment Platform for Images of the Retina (VAMPIRE) software. Measured metrics included vessel width gradient, vessel width intercept, large vessel choroidal vascular density, vessel tortuosity, and vessel fractal dimension.Result131 eyes of 82 MCI patients and 231 eyes of 133 cognitively normal participants were analyzed. Both retinal artery and vein width gradients were less negative in MCI vs. controls, demonstrating decreased rates of vessel thinning towards the periphery (p &lt; 0.001, p = 0.027). Retinal artery and vein width intercepts, a metric that extrapolates vessel width at the center of the optic disc, were smaller in MCI patients vs controls (p &lt; 0.001, p = 0.017). The large vessel choroidal vascular density was greater in MCI patients vs controls (p = 0.025).ConclusionWhen compared to controls with normal cognition, MCI patients had overall thinner retinal vasculature manifested in both the retinal arteries and veins. Furthermore, in MCI, these thinner arteries and veins attenuated at a lower rate when traveling towards the periphery, when compared to controls, perhaps because they were already more attenuated posteriorly. MCI patients also had increased choroidal vascular density.

SLOctolyzer: Fully Automatic Analysis Toolkit for Segmentation and Feature Extracting in Scanning Laser Ophthalmoscopy Images.

The purpose of this study was to introduce SLOctolyzer: an open-source analysis toolkit for en face retinal vessels in infrared reflectance scanning laser ophthalmoscopy (SLO) images. SLOctolyzer includes two main modules: segmentation and measurement. The segmentation module uses deep learning methods to delineate retinal anatomy, and detects the fovea and optic disc, whereas the measurement module quantifies the complexity, density, tortuosity, and caliber of the segmented retinal vessels. We evaluated the segmentation module using unseen data and measured its reproducibility. SLOctolyzer's segmentation module performed well against unseen internal test data (Dice for all-vessels = 0.91; arteries = 0.84; veins = 0.85; optic disc = 0.94; and fovea = 0.88). External validation against severe retinal pathology showed decreased performance (Dice for arteries = 0.72; veins = 0.75; and optic disc = 0.90). SLOctolyzer had good reproducibility (mean difference for fractal dimension = -0.001; density = -0.0003; caliber = -0.32 microns; and tortuosity density = 0.001). SLOctolyzer can process a 768 × 768 pixel macula-centered SLO image in under 20 seconds and a disc-centered SLO image in under 30 seconds using a laptop CPU. To our knowledge, SLOctolyzer is the first open-source tool to convert raw SLO images into reproducible and clinically meaningful retinal vascular parameters. It requires no specialist knowledge or proprietary software, and allows manual correction of segmentations and re-computing of vascular metrics. SLOctolyzer is freely available at https://github.com/jaburke166/SLOctolyzer. SLO images are captured simultaneous to optical coherence tomography (OCT), and we believe SLOctolyzer will be useful for extracting retinal vascular measurements from large OCT image sets and linking them to ocular or systemic diseases.

Numerical simulation of individualized flow diversion cerebral aneurysms treatment

AbstractFlow diverter implantation has emerged as a highly effective treatment for cerebral aneurysms. However, the variability in patient‐specific vascular anatomy necessitates detailed pre‐operative planning to mitigate potential complications arising from standard, one‐size‐fits‐all devices. To address these challenges, robust predictive simulation tools are essential for optimizing flow diverter design and implantation strategies tailored to the unique characteristics of each patient's anatomy. This study focuses on developing an advanced numerical simulation tool for modeling the mechanical behavior of braided flow diverters during crimping and navigation through patient‐specific vasculature. Using isogeometric analysis (IGA) with NURBS‐based representations in LS‐Dyna, the intricate deformations of the flow diverter wires during catheter crimping are captured with high accuracy. The patient‐specific vessel geometries, derived from imaging data, are integrated into the model to account for variations in vascular structure, ensuring precise alignment and controlled navigation of the device. The navigation process relies on optimizing the central axis of the blood vessel to minimize torsional stress on the flow diverter, reducing the risk of device malfunction or failure during deployment. By incorporating patient‐specific information, such as vessel curvature and tortuosity, the simulation tool enables the prediction of potential issues, thus allowing for intervention planning that is tailored to individual anatomy. This patient‐specific approach enhances the safety and efficacy of flow diverter implantation and serves as a foundation for improved device design prior to prototype development.

Retinal microvascular phenotypes can track small vessel disease burden and CPAP treatment effectiveness in obstructive sleep apnoea.

Optical coherence tomography angiography (OCT-A) retinal imaging enables in vivo visualization of the retinal microvasculature that is developmentally related to the brain and can offer insight on cerebrovascular health. We investigated retinal phenotypes and neuroimaging markers of small vessel disease (SVD) in individuals with obstructive sleep apnoea (OSA). We enrolled 44 participants (mean age 50.1 ± SD 9.1 years) and performed OCT-A imaging before and after continuous positive airway pressure (CPAP) therapy. Pre-treatment analyses using a generalized estimating equations model adjusted for relevant covariates, revealed perivascular spaces (PVS) volume in basal ganglia associated with greater foveal vessel density (fVD) (p-value < 0.001), and smaller foveal avascular zone area (p-value = 0.01), whereas PVS count in centrum semiovale associated with lower retinal vessel radius (p-value = 0.02) and higher vessel tortuosity (p-value = 0.01). A reduction in retinal vessel radius was also observed with increased OSA severity (p-value = 0.05). Post-treatment analyses showed greater CPAP usage was associated with a decrease in fVD (p-value = 0.02), and increased retinal vessel radius (p-value = 0.01). The findings demonstrate for the first time the potential use of OCT-A to monitor CPAP treatment and its possible impact on both retinal and brain vascular health.

Abstract 270: Endovascular Versus Medical Management of Acute Ischemic Strokes Due to Distal Medium Vessel Occlusions

Introduction Although endovascular treatment (EVT) is highly effective for acute ischemic strokes due to proximal large vessel occlusions (LVOs), its efficacy and safety in distal medium vessel occlusions (DMVOs) has shown conflicting results. EVT in distal medium vessel occlusions is considered high‐risk due to reduced vessel size and tortuosity, but newer techniques and recent efforts to explore the EVT potential have encouraged us to revisit thrombectomy indications. We thus performed a systematic review and meta‐analysis to compare its efficacy and safety with the best medical treatment (BMT) in treating primary DMVOs. Methods A comprehensive search was performed on Embase, PubMed, and Cochrane from inception to April 2024. Efficacy outcomes of interest included functional independence (90‐day modified Rankin scale (mRS) 0‐2) and excellent functional outcomes (90‐day mRS 0‐1). Safety outcomes were symptomatic intracranial hemorrhage (sICH) and 90‐day mortality. Statistical analysis was performed on Review Manager (RevMan) version 5.3. Results Two randomized controlled trials and twenty observational studies were included in this meta‐analysis with a total sample size of 4081; 1858 (46%) patients were included in the EVT arm and 2223 (54%) belonged to the BMT arm. In the overall cohort, EVT was comparable to BMT in terms of functional independence (OR 0.97, 95% CI 0.74 to 1.28, p=0.86), symptomatic ICH (OR 1.38, 95% CI 0.75 to 2.53), and mortality (OR 1.23, 95% CI: 0.88 to 1.70). A trend towards the superiority of EVT for excellent functional outcomes in strokes with NIHSS score &gt;6 was observed but this finding missed statistical significance by a narrow margin (OR 1.22, 95% CI 0.96 to 1.56, p=0.10). An analysis of studies with mild strokes (NIHSS &lt;6) showed that EVT leads to significantly lower rates of functional independence (OR 0.57, 95% CI 0.33 to 0.99, p=0.05) and also leads to significantly higher rates of sICH in these patients (OR 6.35, 95% CI 1.56 to 25.83, p=0.010). Conclusion BMT is comparable to EVT for distal medium vessel ischemic strokes (AIS‐DMVO). There may be a trend towards EVT achieving higher rates of excellent functional outcomes (mRS 0‐1) in patients with NIHSS score &gt;6 but BMT is superior to EVT in patients with NIHSS score &lt;6.

Abstract 442: Transradial Access For Neurointerventional Procedures In The Elderly Population

Introduction/Purpose Transradial access (TRA) has been shown to be both efficacious and safe across a range of neuro‐interventional procedures. The elderly population represents a sub‐population in which the benefits of TRA could be magnified given their increased risk of access site complications. However, this population may be at higher risk for access site and procedural failure due to their increased likelihood of vessel tortuosity and vascular disease. The current neuro‐interventional literature is lacking with respect to the safety and efficacy of trans‐radial access in the elderly population. Materials/Methods A retrospective review of patients older than 80 years who underwent diagnostic cerebral angiogram or neuro‐endovascular intervention through proximal and distal radial access from 2018 to 2023 at a single center was conducted. Results The mean age of patients who underwent diagnostic cerebral angiogram (N= 35) and endovascular intervention (N= 31) were 82.5 and 83.5 years, respectively (ranges from 80 to 94). Vascular sheath diameters used in the diagnostic and intervention groups were 5 and 5 to 7 French, respectively. Amongst patients in both the diagnostic and intervention groups, proximal radial access was used in 8 and 16 patients, respectively, and distal radial access was used in 27 and 15 patients, respectively. One distal radial access failure occurred in the diagnostic group due to the small diameter of the radial artery. In addition, a patient was switched to femoral access due to the aberrant origin of the right subclavian artery. In the intervention group, there were 4 radial access failures due to difficult anatomy. In the first case, the patient's aortic arch anatomy and proximal left common carotid artery tortuosity prevented guide catheter placement into the left carotid artery. In the second case, the catheter could not be navigated due to proximal left common carotid artery tortuosity. In the third case, the benchmark guide catheter could not be advanced into the left common carotid artery due to significant angulation. In the fourth and final case, the complex radial artery loop could not be navigated. Total failure rates in the diagnostic and intervention groups were 5.7% and 15.2 %, respectively. No access site or other procedural complications were noted. Conclusion Neuro‐interventions are increasingly important concerning the aging population. The benefits of the trans‐radial approach have been well documented as safe and efficacious, with minimal access site complications. Our findings add to the literature, demonstrating that the trans‐radial approach is safe and effective for performing cerebral angiography and neuro‐interventions in octogenarian patients with acceptable crossover and no access site complications

Paclitaxel alters the microvascular network in the central and peripheral nervous system of rats with chemotherapy-induced painful peripheral neuropathy.

Chemotherapy-induced peripheral neurotoxicity (CIPN), with paraesthesia, numbness, dysesthesia and neuropathic pain ranks among the most common dose-limiting toxicity of several widely used anticancer drugs. Recent studies revealed the microvascular angiogenesis as a new important actor, beside peripheral neurons, in the neurotoxicity and neuropathic pain development and chronicisation. The aim of this work is to elucidate the role of vascular alterations in CIPN. We evaluated the severity of CIPN with neurophysiological, behavioural and neuropathological analysis together with the microvascular network in central and peripheral nervous systems of rats in order to correlate the features of the CIPN and the vascular abnormalities. The vascular network was quantitatively evaluated through synchrotron radiation-based X-ray phase-contrast micro-tomography imaging, measuring four specific parameters: vascular density, vessel diameter, vessel tortuosity and branching. Rats exposed to paclitaxel and affected by a severe painful sensory axonopathy showed an increased vascular density (putative sprouting angiogenesis) in the crucial districts of the central (somatosensory cortex and lumbar spinal cord) and peripheral nervous system (lumbar dorsal root ganglia). In addition, the complexity of the vascular network and the size of neo-formed vessels were significantly decreased in specific regions. On the other hand, less significant changes were observed in rats exposed to cisplatin, affected by a painless peripheral neuropathy, suggesting a specific involvement of neo-angiogenesis in the development of severe neurotoxicity and neuropathic pain. These new ground-breaking results can shed light on new pathogenetic mechanisms and potential novel therapeutic approaches for painful-CIPN.

Large bore access for transcatheter aortic valve replacement, endovascular aortic repair, and thoracic endovascular aortic repair. A review of anatomic challenges and operative considerations.

Transcatheter aortic valve replacement (TAVR), endovascular aortic repair (EVAR), and thoracic endovascular aortic repair (TEVAR) are standard and prolific procedures in the modern cardiovascular world, and appropriate delivery of these endoprostheses requires adequate understanding of the requisite large bore access. Percutaneous large bore access is the preferred route but may be accompanied by complications like thrombosis, hemorrhage, or inability to deliver the device. Anatomic limitations such as vessel tortuosity, small size, and heavy calcification may require alternative approaches for successful large bore access. This study aimed to better define large bore access, as well as to elucidate optimal adjuncts and alternatives to enable successful delivery of large bore endoprostheses. A systematic review for "large bore access" in the cardiovascular literature was conducted on PubMed and the Cochrane Library Central according to PRISMA guidelines. Identified articles were filtered and sub-selected for TAVR, EVAR, and TEVAR; studies related to other large bore interventions were excluded. A representative selection of 39 full-text studies included both cardiac and vascular studies and was critically interpreted to identify a consensus definition for large bore access, challenging anatomy, and adjuncts or alternative approaches to the standard transfemoral approach. Transfemoral access remains the first-line approach but in the setting of unfavorable anatomy, adjunct maneuvers (e.g. intravascular lithotripsy, endoconduits) or alternative approaches (supra-aortic, transcaval) help decrease morbidity, mortality, length of procedure, and overall health care cost in large bore access.

A New Retest-Stable Tortuosity Metric for Retinal Vessel Analyses.

Existing retinal vessel tortuosity metrics lack standardization and retest reliability, hindering their clinical utility. Our study addresses this gap by introducing a novel metric, coined as the "vascular curvature index" (VCI), to enhance accuracy and consistency in biomarkers associated with medical conditions. We assess VCI's performance in terms of retest reliability in healthy subjects to transform early detection and monitoring approaches for various diseases. We recruited 44 patients for a single-session study, capturing fundus images before and after a five-minute break. Using AutoMorph, we generated vessel segmentation maps and evaluated retest reliability using multiple tortuosity metrics. The VCI was introduced and statistically compared to existing metrics. We performed a paired one-sided t-test to test for significantly improved retest reliability of our newly proposed metric. We analyzed distribution histograms, Fisher-Pearson coefficient of skewness, and correlation matrices for further insights. VCI is the most retest-reliable metric, statistically surpassing other curvature metrics, except inverse spherical radius tortuosity. With a somewhat negatively distributed pattern (coefficient of skewness of -0.52), VCI exhibits the strongest correlation with the second most retest-reliable metric; inverse-radius-tortuosity (Pearson and Spearman correlation of 0.7 and 0.72, respectively). Its correlation with angle-tortuosity is lower (Pearson and Spearman correlation of 0.05 and 0.07, respectively). The VCI emerges as a highly retest-reliable metric with a relatively normal distribution in healthy patients. Further investigation is warranted to evaluate its clinical performance in real-world applications, potentially influencing proactive healthcare interventions and personalized treatment decision-making.

Ocular Manifestations of Carotid Cavernous Fistula: A Case of Macular Edema and Conjunctival Vessel Tortuosity

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/policies/article-withdrawal.

Vascular Biomarkers for Pulmonary Nodule Malignancy: Arteries vs. Veins.

This study aims to investigate the association between the arteries and veins surrounding a pulmonary nodule and its malignancy. A dataset of 146 subjects from a LDCT lung cancer screening program was used in this study. AI algorithms were used to automatically segment and quantify nodules and their surrounding macro-vasculature. The macro-vasculature was differentiated into arteries and veins. Vessel branch count, volume, and tortuosity were quantified for arteries and veins at different distances from the nodule surface. Univariate and multivariate logistic regression (LR) analyses were performed, with a special emphasis on the nodules with diameters ranging from 8 to 20 mm. ROC-AUC was used to assess the performance based on the k-fold cross-validation method. Average feature importance was evaluated in several machine learning models. The LR models using macro-vasculature features achieved an AUC of 0.78 (95% CI: 0.71-0.86) for all nodules and an AUC of 0.67 (95% CI: 0.54-0.80) for nodules between 8-20 mm. Models including macro-vasculature features, demographics, and CT-derived nodule features yielded an AUC of 0.91 (95% CI: 0.87-0.96) for all nodules and an AUC of 0.82 (95% CI: 0.71-0.92) for nodules between 8-20 mm. In terms of feature importance, arteries within 5.0 mm from the nodule surface were the highest-ranked among macro-vasculature features and retained their significance even with the inclusion of demographics and CT-derived nodule features. Arteries within 5.0 mm from the nodule surface emerged as a potential biomarker for effectively discriminating between malignant and benign nodules.

OCTA-ReVA: an open-source toolbox for comprehensive retinal vessel feature analysis in optical coherence tomography angiography.

Optical coherence tomography angiography (OCTA) has significantly advanced the study and diagnosis of eye diseases. However, current clinical OCTA systems and software tools lack comprehensive quantitative analysis capabilities, limiting their full clinical utility. This paper introduces the OCTA Retinal Vessel Analyzer (OCTA-ReVA), a versatile open-source platform featuring a user-friendly graphical interface designed for the automated extraction and quantitative analysis of OCTA features. OCTA-ReVA includes traditional established OCTA features based on binary vascular image processing, such as blood vessel density (BVD), foveal avascular zone area (FAZ-A), blood vessel tortuosity (BVT), and blood vessel caliber (BVC). Additionally, it introduces new features based on blood perfusion intensity processing, such as perfusion intensity density (PID), vessel area flux (VAF), and normalized blood flow index (NBFI), which provide deeper insights into retinal perfusion conditions. These additional capabilities are crucial for the early detection and monitoring of retinal diseases. OCTA-ReVA demystifies the intricate task of retinal vasculature quantification, offering a robust tool for researchers and clinicians to objectively evaluate eye diseases and enhance the precision of retinal health assessments.