Site Of Stenosis Research Articles

Risk factors for urinary retention after robot-assisted radical cystectomy with orthotopic neobladder diversion: a multicenter study.

To determine risk factors for urinary retention (UR) after robot-assisted radical cystectomy (RALC) with orthotopic neobladder diversion. A total of 269 patients who underwent RALC with orthotopic neobladder diversion from 2008 to 2019 at seven tertiary hospitals were retrospectively analyzed. There were 68 patients who had UR (UR arm) and 201 patients who did not have UR (no-UR arm). UR was defined as voiding dysfunction without catheterization or more than 100mL of residual urine after voiding. Preoperative demographics, perioperative factors, pathology outcomes, and postoperative complications of UR and no-UR arms were compared and predictors of UR were identified. Among demographic factors, only gender proportion showed a difference, with male proportion being significantly lower in the UR arm than in the no-UR arm (81% vs 92%, p = 0.010). For perioperative outcomes, anastomosis site stricture (27% vs 11%, p = 0.003) and length of hospital stays (23days vs. 19days, p = 0.001) were significantly higher in the UR arm than in the no-UR arm. In multiple logistic regression analysis, female (OR 3.32, 95% CI: 1.43-7.72) and body mass index (BMI) (OR 1.10, 95% CI 1.00-1.20) were UR predictors. UR after RALC with orthotopic neobladder diversion is significantly increased in females. Multiple logistic regression analysis identified female and BMI elevation as UR predictors.

Clinical efficacy of DSA-based features in predicting outcomes of acupuncture intervention on upper limb dysfunction following ischemic stroke

Background and objectivesThis study aimed to employ machine learning techniques to predict the clinical efficacy of acupuncture as an intervention for patients with upper limb motor dysfunction following ischemic stroke, as well as to assess its potential utility in clinical practice.MethodsMedical records and digital subtraction angiography (DSA) imaging data were collected from 735 ischemic stroke patients with upper limb motor dysfunction who were treated with standardized acupuncture at two hospitals. Following the initial screening, 314 patient datasets that met the inclusion criteria were selected. We applied three deep-learning algorithms (YOLOX, FasterRCNN, and TOOD) to develop the object detection model. Object detection results pertaining to the cerebral vessels were integrated into a clinical efficacy prediction model (random forest). This model aimed to classify patient responses to acupuncture treatment. Finally, the accuracies and discriminative capabilities of the prediction models were assessed.ResultsThe object detection model achieved an optimal recognition rate, The mean average precisions of YOLOX, TOOD, and FasterRCNN were 0.61, 0.7, and 0.68, respectively. The prediction accuracy of the clinical efficacy model reached 93.6%, with all three-treatment response classification area under the curves (AUCs) exceeding 0.95. Feature extraction using the prediction model highlighted the significant influence of various cerebral vascular stenosis sites within the internal carotid artery (ICA) on prediction outcomes. Specifically, the initial and C1 segments of the ICA had the highest predictive weights among all stenosis sites. Additionally, stenosis of the middle cerebral, anterior cerebral, and posterior cerebral arteries exerted a notable influence on the predictions. In contrast, the stenosis sites within the vertebral artery exhibited minimal impact on the model's predictive abilities.ConclusionsResults underscore the substantial predictive influence of each cerebral vascular stenosis site within the ICA, with the initial and C1 segments being pivotal predictors.

Neurosarcoidosis Masquerading as Spinal Stenosis.

A 65-year-old woman was admitted to the neurology department with a suspected demyelinating disease due to complaints of progressive pain and weakness in both upper and lower limbs, as well as urinary incontinence. MRI of the spine revealed complex disc osteophyte with compression of the spinal cord in the cervical and lumbar spine at several vertebral levels, and localized enhancement in the cervical spine at the site of maximal spinal canal stenosis. During her hospitalization, the patient underwent extensive evaluation to rule out any systematic inflammatory diseases, infections, and malignancy. Chest CT revealed bilateral mediastinal lymphadenopathy. Transbronchial mediastinal lymph node biopsy showed numerous non-necrotizing granulomas without evidence of malignancy. After a thorough and careful exclusion of a demyelinating, infectious, and paraneoplastic myelopathies, and based on clinical, radiographic, and pathological findings, the patient was diagnosed with both neurosarcoidosis and spondylotic myelopathy. She was then treated for neurosarcoidosis, including glucocorticosteroids, azathioprine, and a biosimilar of the anti-TNF alpha agent infliximab, resulting in both clinical and radiographic improvement. Intramedullary spinal neurosarcoidosis is very rare and may present with clinical features of spondylotic myelopathy, with typical imaging findings occurring only in areas of spinal canal stenosis.

Association of pancreatic atrophy patterns with intraductal extension of early pancreatic ductal adenocarcinoma: a multicenter retrospective study.

Focal pancreatic parenchymal atrophy (FPPA) and upstream pancreatic atrophy (UPA) may indicate the presence of early pancreatic cancer. In early pancreatic cancer, the tumor occasionally spreads laterally along the main pancreatic duct, presenting challenges in determining the extent of surgical resection. This study aimed to investigate the association of pancreatic atrophy pattern and intraductal cancer extension. Thirty-two patients with early-stage pancreatic cancer who underwent surgery at five participating centers were enrolled. Pancreatic atrophy was defined as the narrowing of parenchyma compared to the surrounding parenchyma and was classified as either FPPA (partial atrophy surrounding the pancreatic duct stenosis) or UPA (global atrophy caudal to the site of duct stenosis). Intraductal cancer extension was defined as an extension exceeding 10mm. Preoperative computed tomography revealed FPPA, UPA, and no parenchymal atrophy in 13, 13, and 6 patients. Cases with FPPA or UPA showed significantly longer cancer extensions than those without atrophy (P = 0.005 and P = 0.03, respectively). Intraductal cancer extension was present in all but one case of FPPA. 69% (9/13) of the cases with UPA showed intraductal cancer extension, whereas cases without atrophy showed no intraductal cancer extension. Importantly, two patients with FPPA or UPA showed positive resection margins during surgery and three patients with FPPA or UPA showed recurrence in the remnant pancreas. The presence of FPPA and UPA indicates lateral cancer extension in early-stage pancreatic cancer. Preoperative assessment of the pancreatic parenchyma may provide valuable insights for determining the extent of surgical resection.

Pretrained subtraction and segmentation model for coronary angiograms

This study introduces a novel self-supervised learning method for single-frame subtraction and vessel segmentation in coronary angiography, addressing the scarcity of annotated medical samples in AI applications. We pretrain a U-Net model on a large dataset of unannotated coronary angiograms using an image-to-image translation framework, then fine-tune it on a limited set of manually annotated samples. The pretrained model excels at comprehensive single-frame subtraction, outperforming existing DSA methods. Fine-tuning with just 40 samples yields a Dice coefficient of 0.828 for vessel segmentation. On the public XCAD dataset, our model sets a new state-of-the-art benchmark with a Dice coefficient of 0.755, surpassing both unsupervised and supervised learning approaches. This method achieves robust single-frame subtraction and demonstrates that combining pretraining with minimal fine-tuning enables accurate coronary vessel segmentation with limited manual annotations. We successfully apply this approach to assist physicians in visualizing potential vascular stenosis sites during coronary angiography. Code, dataset, and a live demo will be available available at: https://github.com/newfyu/DeepSA.

Intravascular delivery of an MK2 inhibitory peptide to prevent restenosis after angioplasty

Peripheral artery disease is commonly treated with balloon angioplasty, a procedure involving minimally invasive, transluminal insertion of a catheter to the site of stenosis, where a balloon is inflated to open the blockage, restoring blood flow. However, peripheral angioplasty has a high rate of restenosis, limiting long-term patency. Therefore, angioplasty is sometimes paired with delivery of cytotoxic drugs like paclitaxel to reduce neointimal tissue formation. We pursue intravascular drug delivery strategies that target the underlying cause of restenosis - intimal hyperplasia resulting from stress-induced vascular smooth muscle cell switching from the healthy contractile into a pathological synthetic phenotype. We have established MAPKAP kinase 2 (MK2) as a driver of this phenotype switch and seek to establish convective and contact transfer (coated balloon) methods for MK2 inhibitory peptide delivery to sites of angioplasty. Using a flow loop bioreactor, we showed MK2 inhibition in ex vivo arteries suppresses smooth muscle cell phenotype switching while preserving vessel contractility. A rat carotid artery balloon injury model demonstrated inhibition of intimal hyperplasia following MK2i coated balloon treatment in vivo. These studies establish both convective and drug coated balloon strategies as promising approaches for intravascular delivery of MK2 inhibitory formulations to improve efficacy of balloon angioplasty.

Factors influencing primary patency time of percutaneous transluminal balloon angioplasty for hemodialysis arteriovenous grafts

Objective: To investigate the factors affecting primary patency time in arteriovenous graft (AVG) patients receiving percutaneous transluminal balloon angioplasty (PTA). Methods: Hemodialysis patients who underwent AVG placement at the First Affiliated Hospital of Chongqing Medical University between February 2018 and December 2021 were included. The factors including age, gender, total duration of AVG use, site of stenosis, degree of stenosis, length of stenosis, residual stenosis, and presence of thrombosis were analyzed, and influencing factors of primary patency time in AVG were determined using a multiple linear regression model. Results: A total of 101 patients who underwent 331 PTA treatments were enrolled, including 35 males and 66 females. The median age of patients undergoing PTA for the first time was 61 (51, 68) years, and the primary patency time after PTA was 5 (3, 10) months. The patients were followed up for (38.5±15.3) months. Multivariable linear regression analysis revealed that severe stenosis at the venous anastomosis and reflux veins (β=-2.773, 95%CI:-5.440--0.105, P=0.042), female (β=-2.247, 95%CI:-3.853--0.642, P=0.006), and previous multiple PTA treatments (β=-0.516, 95%CI:-0.978--0.054, P=0.029) were risk factors for a shorter primary patency time after PTA. Conclusion: Severity of stenosis at the venous anastomosis and reflux veins of the AVG, female, and a history of multiple previous PTA treatments are associated with a shorter primary patency time in AVG patients.

Prevalence and intervention effect of arteriovenous graft stenosis

Objective: To evaluate the prevalence, intervention methods and effect of arteriovenous graft (AVG) stenosis. Methods: The clinical data of patients who received AVG in the Blood Purification Center, the First Affiliated Hospital of Zhengzhou University from January 2018 to December 2022 were retrospectively analyzed. The patency rate, prevalence and intervention effect of AVG stenosis were analyzed. Results: A total of 475 patients aged (55.5±11.8) years were included, and there were 193 male cases (40.6%) and 282 female cases (59.4%). The patients were followed up for [M (Q1, Q3)] 19 (12, 30) months, and the primary, assisted primary and secondary patency were 14 (5, 27), 27 (13, 55), and 59 (33, 65) months, respectively. There were 799 access events which needed intervention, with a total standardized intervention rate of 0.90 per patient-year. Totally, 431(53.9%, 431/799) stenosis events occurred in 207 AVG. Among 422 AVG stenosis events with complete clinical data, 57.8% (244/422) were multi-site stenosis and 42.2% (178/422) were single-site stenosis. The most common sites of stenosis were graft-vein anastomosis (47.6%, 340/715), venous outflows (22.7%, 162/715), and puncture zone (20.0%, 143/715). In the 414 stenosis with intact follow-up data, 90.8% (376/414) were treated by balloon angioplasty, 8.5% (35/414) received covered stent insertion, and 0.7% (3/414) were intervened by open surgery. Clinical success rate was 98.1% (406/414). The primary patency time after endovascular treatment was 6 (4, 12) months. Covered stent significantly increased post-intervention primary patency time compared withballoon angioplasty [6 (3, 7) months vs 3 (1, 4) months, P=0.020]. Conclusions: Stenosis is the most common complication of AVG, and the most common sites are graft-vein anastomosis, venous outflows, and puncture zone. Intervention of AVG stenosis has a high clinical success rate, and a relatively low post-intervention patency. Covered stent insertion improves the post-intervention patency of AVG, which has a poor effect using balloon expansion.

ASSESSMENT OF GROWTH AND RUPTURE OF CAROTID ATHEROSCLEROSIS AND PLAQUE WITH DIFFERENT DEGREES OF STENOSIS

In this study, the growth and rupture of plaque were investigated to predict the development of carotid atherosclerosis and plaque. Realistic 3D models of multi-component plaque and carotid artery were established in healthy, mild, moderate, and severe stenosis. Fluid–structure interaction (FSI) simulations were performed on these models, and the wall shear stress (WSS), time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), and wall tensile stress (WTS) in a natural cardiac cycle were analyzed to assess the epidermal rupture, growth tendency, and internal rupture of plaques in a natural state. Results show that in severe stenosis, the WSS at the stenosis sites exceeds the threshold of rupture during almost the entire cardiac cycle, thus causing an epidermal injury, bringing about plaque detachment and thrombosis. TAWSS decreased and OSI and RRT increased in the bifurcation region and the downstream region of the plaque. The deposition is more likely to occur in these regions. A higher degree of stenosis will increase the OSI and RRT in the downstream region of the plaque, leading to continuous deterioration of the plaque, while the degree of stenosis has little effect on the upstream region of the plaque. The fibrous cap is the starting point for rupture within the plaque, and calcification increases the stress on the fibrous cap, thereby increasing the risk of rupture.

Laparoscopic left hepatectomy for a patient with an absence of portal bifurcation using real-time imaging: a case report

BackgroundAbsence of portal bifurcation is an extremely rare anomaly that should be recognized preoperatively, especially prior to a major hepatectomy.Case presentationA 45-year-old woman presented with abdominal pain, and abdominal computed tomography (CT) revealed dilatation of both the common bile duct (CBD) and intrahepatic bile duct (IHBD). Endoscopic retrograde cholangiopancreatography (ERCP) showed CBD and IHBD stones (B2 and B4). The CBD stones were removed, but the IHBD stones could not be, yet there was no evidence of malignancy at the site of IHBD stenosis. Enhanced CT revealed a dilated IHBD, while three-dimensional CT images showed the left portal vein running through the ventral side of the middle hepatic vein, which was diagnosed as the absence of portal vein bifurcation (APB). Laparoscopic left hepatectomy was successfully performed using real-time indocyanine green (ICG) fluorescence imaging.ConclusionSurgeons should be aware of the possibility of APB, a rare portal vein anomaly, before performing major hepatectomy. Real-time ICG fluorescence imaging may be helpful to ensure the precise anatomy of the liver during laparoscopic surgery.

Importance of provoked spasms at the sites of nonobstructive stenosis as well as at the sites of obstructive stenosis in patients with obstructive coronary arteries and coronary spasm.

There are few reports regarding the prognosis in patients with obstructive coronary artery disease (OCAD) and vasospastic angina (VSA). This study investigated the clinical characteristics and clinical outcomes in patients with VSA and OCAD, especially regarding provoked spasm phenotypes and sites. This was a retrospective, observational, single-center study of 403 patients with typical or atypical angina-like chest pain undergoing acetylcholine (ACH) spasm provocation testing and OCAD. An obstructed coronary artery was defined as ≥50% luminal narrowing. We defined positive epicardial spasm as ≥90% transient stenosis and usual chest symptoms or ischemic ECG changes. Among these 403 patients with OCAD, positive spasm by intracoronary ACH testing was observed in 196 patients (49%), whereas negative spasm was found in the remaining 207 patients (51%). The clinical outcomes in the patients with OCAD and provoked spasm were not different according to the provoked-spasm phenotypes. Furthermore, the clinical outcomes were unsatisfactory in the patients with spasm at the site of nonobstructive lesion alone compared with those with spasm at the site of obstructive and nonobstructive lesions. We should precisely diagnose patients with OCAD who have provoked spasm by using intracoronary ACH testing and medicate the nonobstructive vessels in patients with OCAD and VSA under optimal coronary vasodilators.

Duodenal-Jejunal Stenosis as a Manifestation of Eosinophilic Gastroenteritis: A Case Report

Introduction: Eosinophilic gastroenteritis (EGE) is a rare disorder characterized by eosinophilic infiltration of the stomach and small intestine. Its clinical manifestations depend on the extent, location, and depth of the inflammatory infiltrate. The pathogenesis remains unclear, but it may be related to food allergy or other hypersensitivity reactions in some patients. Untreated cases can cause intestinal stricture or perforation, making timely diagnosis and intervention essential. Clinical case: A 13-year-old male adolescent was hospitalized due to symptoms suggesting intestinal obstruction or alterations in intestinal motility. Medical imaging revealed significant gastric distension and delayed gastric emptying. An endoscopic study showed a “snake-skin” pattern, duodenitis due to food stasis, a 2 cm ulcer, and stenosis in the duodenum. The biopsy confirmed EGE with significant irregular eosinophilic infiltration of the lamina propria. A panendoscopy was performed after steroid treatment without being able to assess the site of stenosis and perform pneumatic dilation. After completing the immunomodulatory management, a contrast-enhanced abdominal tomography was performed showed a significant decrease in the intestinal lumen, therefore an exploratory laparotomy with a lateral to lateral jejune-jejunal anastomosis was performed. Discussion: EGE is a rare inflammatory disorder characterized by eosinophilic infiltration of the stomach and small intestine. Symptoms are based on the affected gastrointestinal tract segment. In this case, our patient presented intestinal obstruction symptoms with endoscopic biopsies and a histopathological study confirmed eosinophil infiltration. Treatment typically involves identifying potential triggers and corticosteroids to reduce inflammation and symptoms. However, in this case, a decrease in the intestinal lumen was observed, therefore an elective surgical resection was performed. Conclusion: Eosinophilic gastroenteritis is a rare disorder that requires strong clinical suspicion to be diagnosed, which is why its knowledge is important. In this case, gastrointestinal symptoms, radiological and endoscopic images, in addition to the histopathological report, were key tools for integrating the diagnosis. Although management with steroids and immunomodulators was not successful, surgical management became an appropriate option as definitive treatment.

High Prevalence of Myocardial Bridging Detected in an Indonesian Population Using Multi-Detector Computed Tomography.

Background and Objectives: Myocardial bridging (MB) is still not yet considered a significant finding in Indonesia both radiographically and clinically. Hence, this article aims to assess the prevalence of MB using multi-detector computed tomography (MDCT) and look at factors contributing to stenosis amongst patients with MB. Materials and Methods: This study is cross-sectional in a single centre, with consecutive sampling, looking at all patients who underwent a multi-detector computed tomography (MDCT) scan from February 2021 until February 2023. GraphPad Prism version 9.0.0 for Windows (GraphPad Software, Boston, MA, USA) was used to analyse the results. Results: There are 1029 patients with an MB, yielding a prevalence of 44.3% (95%CI 42.3-46.4). The left anterior descending vessel is the most commonly implicated, with 99.6%. Among those with stenosis, the middle portion of the bridging vessel is the most common site of stenosis (n = 269), followed by the proximal portion (n = 237). The severity of stenosis is more often moderate, with 30-50% (n = 238). Females (odds ratio [OR] of 1.8, 95%CI 1.4-2.3; p-value < 0.0001), older age (t-value 5.6, p-value < 0.0001), symptomatic patients (OR 1.4, 95% CI 1.1-1.9; p-value = 0.013), and higher mean coronary artery calcium score (t-value 11.3, p-value < 0.0001) are more likely to have stenosis. The degree of stenosis is significantly higher in the proximal stenosis group than in the middle stenosis group (t-value 27, p-value < 0.0001). Conclusions: Our research demonstrates that MB may prevent atheromatosis of the coronary segment distal to the MB and predispose the development of atherosclerosis in the section proximal to the bridge.

Outcomes of Surgical and Endovascular Treatment for Cephalic Arch Stenosis in Proximal Arteriovenous Fistula.

The cephalic arch is a significant site of stenosis in proximal arteriovenous fistulas (AVFs) that contributes to access dysfunction and thrombosis. This study aimed to evaluate the outcomes of surgical treatment (ST) and endovascular treatment (ET) for cephalic arch stenosis (CAS). A total of 62 patients with proximal AVF who underwent CAS revision using either ST or ET were enrolled between January 2018 and March 2023. In the ET group, only the initial ET following AVF formation was considered, to mitigate bias. In the ST group, central transposition of the native AVF (transposition group) or interposition of the prosthetic graft into the proximal basilic or axillary vein (interposition group) was performed. We evaluated primary and functional patency based on these groups and calculated the number of patency loss events after CAS treatment. Of the 62 patients, 38 (61%) were male, with a mean age of 66.4 years. ST was performed in 26 (42%) patients, including transposition in 16 and interposition in 10, whereas ET was administered to 36 patients during the study period. Among the ST recipients, 42% had a history of ET for CAS. The incidence of AVF thrombosis was marginally higher in the ST group than in the ET group (39% vs. 19%, P=0.098). The primary patency rates at 6 months, 1 year, and 3 years were 87%, 87%, and 66% in the transposition group; 45%, 23%, and 11% in the interposition group; and 66%, 49%, and 17% in the ET group, respectively. Notably, the primary patency of the transposition group was significantly higher than that of the interposition (P=0.001) and ET groups (P=0.016). The frequency of patency loss events per person-year after the initial revision was 0.40, 0.52, and 1.42 in the transposition, interposition, and ET groups, respectively. Transposition exhibited the most favorable primary patency rate and the lowest number of subsequent patency loss events during follow-up despite the higher rates of AVF thrombosis and previous ET at presentation. Consequently, transposition should be actively considered in eligible patients with CAS.

Occipital venous sinus stenting for idiopathic intracranial hypertension and pulsatile tinnitus: A case series.

Venous sinus stenting for dural venous sinus outflow obstruction due to an intrinsic filling obstruction or extrinsic stenosis is an increasingly popular treatment strategy for idiopathic intracranial hypertension (IIH) and isolated pulsatile tinnitus (PT). The most common site of stenosis is the lateral venous sinus at the transverse-sigmoid junction. Approximately 10% of the population has a persistent occipital venous sinus (OVS), a variant that may be the dominant venous drainage pathway in the setting of a hypoplastic or aplastic transverse sinus. OVS stenosis has been rarely associated with IIH and isolated PT with only a handful published cases. We herein report a retrospective series of OVS stenting in five patients, four of whom presented with non-IIH PT and one with IIH.

Balloon venoplasty for right heart catheterization from the arm in patients with subclavian vein stenosis.

In the trans-radial era, arm venous access for right heart catheterization (RHC) is rising. Procedural success is affected by many factors, including subclavian/innominate vein stenosis (SVS) and pre-existing wires or catheters. In a study published previously by the same authors, 2% of cases had unsuccessful RHC through the arm, predominantly due to SVS. Since that study, techniques to improve RHC success rates have been developed, including crossing the stenosis with a coronary guidewire, followed by balloon dilatation. We aimed to determine whether subclavian/innominate venoplasty allows successful RHC in patients with SVS. Our retrospective study included patients who had RHC from the arm between November 1, 2019, and December 31, 2022 that was unsuccessful due to the inability to pass a catheter through the SVS, and then underwent balloon venoplasty. The success rate of completed RHC was then assessed. Out of 2506 RHCs via arm access, 2488 were successful with a catheter alone or over a guidewire. In 18 patients, venoplasty was needed for catheter passage over a guidewire. Post-dilatation, all 18 cases (100%) had successful RHC with a mean procedural time of 35.2 (SD = 15.5) minutes. The most common stenosis site was the subclavian vein in 13 patients (72.2%), and 12 patients (66.7%) had pacemaker/ implantable cardioverter defibrillator wires present. Balloon dilatation of SVS is an efficacious method to improve the success rate of RHC from the arm. It is a safe technique that may prevent cross-over to a different access site, thereby improving patient satisfaction and reducing the possibility of alternate site complications.

Abstract 1159: Harnessing Limb Revascularization With Synthetic Probiotics

Peripheral arterial disease (PAD) is a critical vascular condition that results in impaired blood flow leading to chronic limb threatening ischemia (CLTI), tissue necrosis and oftentimes to lower-limb amputation. This is largely due to suboptimal revascularization and inflammatory programs, that fail to instigate neovascularization at sites of vessel stenosis. The incidence of CLTI is on the rise but yet there is a paucity of effective treatment options for patients. We hypothesized that the coordinated action of regenerative angiogenesis and immunosurveillance would likely stimulate effective revascularization in the ischemic leg. The neuroimmune cue, Netrin-1 has been shown to possess such properties. We have shown that Netrin-1 can assist atherosclerosis onset by modulating macrophage chemotaxis and shown its critical role in modulating vascular remodeling. Here we show that the conditional knock-down of Netrin-1 in myeloid cells (Ntn1 flox/flox LysM cre+ ), protects mice from revascularization following femoral artery ligation compared to WT littermates. The deletion of Netrin-1 in endothelial cells nor vascular smooth muscle cells was insufficient to produce such effects. Notably, in human amputated tissue sections, the expression of Netrin-1 was repressed at sites proximal to amputated sites compared to distal regions with preserved blood flow. Tissue macrophages were packed with Netrin-1 and it exerted its effects in an autocrine/paracrine manner via its receptor Unc5b. The use of synthetic biology to engineer bacteria with tailored functionalities presents a cutting-edge avenue for developing novel therapeutic tools. We therefore employed a synthetic biology approach to deliver exogenous Netrin-1 to the ischemic leg. The Nissle probiotic was genetically engineered to overexpress murine Netrin-1. The local administration of this probiotic to ischemic limb of Ntn1 flox/flox LysM cre+ mice was sufficient to recapitulate blood flow and reperfusion in the leg comparable to WT mice (and sham probiotic) in 2 weeks. Our results show the therapeutic potential of the use of synthetic microorganisms and Netrin-1 for innovative and adaptable solutions in limb regenerative medicine.

Hemodynamic assessment of severely stenotic carotid arteries

Internal carotid artery (CA) stenosis is a primary etiological factor for stroke and transient ischemic attack. The severity of arterial stenosis significantly impacts patient health and treatment decisions. Therefore, we conducted computational fluid dynamics analyses on five carotid arteries (CAs) of severe stenosis and compared them with five CAs in the control group. We improved the three-element Windkessel model method by pre-calculating the constant-pressure outlet simulation of the first cardiac cycle, which accelerated the stability of the model. The research results show that vortices were observed at the bifurcation of the CAs in the control group, whereas in the severe stenosis group, vortices predominantly occurred within the carotid sinus downstream of the stenotic segment. Notably, the vortex flow in the carotid aneurysm downstream of the stenotic segment arises due to the cross-sectional constriction induced by stenosis, which always flows in a clockwise direction and may contribute to the formation of aneurysms distal to the stenotic region. A high time-averaged wall shear stress value can effectively identify the stenosis site of CAs, while a high relative residence time value marks the protrusion near the stenosis segment. This study delved into the hemodynamic parameters between the CAs of the severe stenosis group and the control group and provided robust clinical evidence for carotid atherosclerotic disease.

Dynamic Cervical Spinal Canal Stenosis: Identifying Imaging Risk Factors in Extended Positions.

A retrospective study at a single academic institution. This study aimed to identify imaging risk factors for stenosis in extended neck positions undetectable in preoperative neutral magnetic resonance imaging (MRI) and improving decompression strategies for cervical spine disorders. Cervical disorders are influenced by various dynamic factors, with spinal stenosis appearing during neck extension. Despite the diagnostic value of dynamic cervical MRI, standard practice often uses neutral-position MRI, potentially influencing surgical outcomes. This study analyzed 143 patients who underwent decompression surgery between 2012 and 2014, who had symptomatic cervical disorders and MRI evidence of spinal cord or nerve compression but had no history of cervical spine surgery. Patient demographics, disease type, Japanese Orthopedic Association score, and follow-up periods were recorded. Spinal surgeons conducted radiological evaluations to determine stenosis levels using computed tomography myelography or MRI in neutral and extended positions. Measurements such as dural tube and spinal cord diameters, cervical alignment, range of motion, and various angles and distances were also analyzed. The residual space available for the spinal cord (SAC) was also calculated. During extension, new stenosis frequently appeared caudal to the stenosis site in a neutral position, particularly at C5/C6 and C6/C7. A low SAC was identified as a significant risk factor for the development of new stenosis in both the upper and lower adjacent disc levels. Each 1-mm decrease in SAC resulted in an 8.9- and 2.7-fold increased risk of new stenosis development in the upper and lower adjacent disc levels, respectively. A practical SAC cutoff of 1.0 mm was established as the threshold for new stenosis development. The study identified SAC narrowing as the primary risk factor for new stenosis, with a clinically relevant cutoff of 1 mm. This study highlights the importance of local factors in stenosis development, advocating for further research to improve outcomes in patient with cervical spine disorders.

Remodeling of extracranial veins and venous-arterial imbalance in extrinsic stenosis and hypoplasia of the internal jugular veins

The aim of the study was to compare hemodynamic parameters, the sequence of remodeling of the jugular and extrajugular outflow tracts of cerebral venous circulation in extrinsic stenosis and hypoplasia of the internal jugular vein (IJV). Material and methods. Groups with external compression and IJV stenosis (n = 50), with IJV hypoplasia (n = 27), and after IJV ligation/resection (n = 6) as a model of IJV occlusion with a minimal cerebral venous insufficiency and venous encephalopathy and control group (n = 31) were compared. All patients underwent a neurological examination, ultrasound duplex scanning of the IJV (J2 and at the level of stenosis), common carotid and vertebral artery (V2), 2DToF or 3DToF magnetic resonance venography of the neck veins. The degree of stenosis of the IJV, the crosssectional area and the time average blood flow velocity, the calculated indicator of the venous-arterial balance (VAB) were determined according to the modified formula. Results and discussion. In the group of external compression of the IJV, stenosis averaged 64.52 %. The area of the IJV at the site of stenosis was 6 times, and at the standard place (J2) – 3 times less than the area of the opposite IJV. The hypoplastic IJV throughout its entire length (from J1 to J3) had the same area (0.21 ± 0.12 cm2 ), smooth contours, without local expansions or narrowings. A very low blood flow velocity (10.2 ± 11.67 cm/s) is characteristic for stenosis, in contrast to the normal velocity in the hypoplastic vein and in the control group. The blood flow velocity in the contralateral IJV with external stenosis does not differ from normal, but it is increased with hypoplasia (34.62 ± 12.23 cm/s). With MR venography, it is possible to detect a stenosing factor, symptoms of a filling defect, a decrease or loss of a blood flow signal, and an assessment of the overall picture of remodeling of the venous network of the neck. A decrease in the IJV area on the side of the lesion/anomaly corresponds to negative remodeling, while an expansion of the opposite IJV corresponds to positive remodeling. If the obstruction persists, the homolateral, then the contralateral external jugular vein expands, then the vertebral veins and plexuses, spinal epidural veins, anterior jugular and posterior cervical veins expand too. The magnitude of the IJV on the side of the anomaly/pathology with hypoplasia did not differ from the value with stenosis (9 %), but was slightly less than on the opposite IJV (53.39 ± 13.40 and 67.24 ± 18.02 %, respectively, p &lt; 0.06) and significantly less compared to the control (24.16 ± 8.06 % on the left and 33.15 ± 8.27 % on the right, p &lt; 0.0001), which makes this indicator a good additional criterion for outflow abnormality according to the IJV of one side.