Takahashi, Edwin A

Purpose The purpose of this study was to identify risk factors and evaluate clinical outcomes associated with incidental left common iliac vein compression on CT imaging. Methods This is a retrospective study that reviewed venous-phase abdomen and pelvis CT scans to identify patients with incidental extrinsic compression of the left common iliac vein due to an overlying right common iliac artery. A total of 726 patients were included (364 females, 362 males; mean patient age: 61.9 ± 15.9 years). Board-certified radiologists reviewed all CT scans. Significant left iliac vein compression was defined as >50% luminal narrowing. Results Significant iliac vein compression was identified in 114 (15.7%) patients and was more common in females (19.5%) versus males (11.9%) ( p < 0.01). Patients with iliac vein compression >50% had significantly lower BMI than those without compression (24.8 ± 6.2 vs 28.7 ± 7.2 kg/m 2 , p < 0.01). Patients with incidental left iliac vein compression had a higher rate of prior left lower extremity DVT ( p = 0.02). Conclusion Incidental left common iliac vein compression was present in approximately 16% of patients and was more frequent among females. Compression was associated with lower BMI and more than twice the rate of ipsilateral DVT, despite no prior diagnosis of MTS. These findings suggest that incidental iliac vein compression could have more clinical significance than previously recognized.

Renovascular hypertension is the most common cause of secondary hypertension, and radiologist awareness of the various imaging appearances and various causes is crucial for accurate diagnosis and guiding treatment.

Worldwide, more than 4 million patients with end-stage kidney disease require hemodialysis through an arteriovenous fistula (AVF). AVFs fail because of venous neointimal hyperplasia (VNH) resulting in venous stenosis formation. A phase 1 randomized trial in patients undergoing upper extremity AVF placement was performed to evaluate the safety and efficacy of autologous adipose–derived mesenchymal stem cells (MSCs) in improving AVF function. The mechanism of action by which MSCs exert their beneficial effects was investigated using AVFs created in mice and pigs treated with allogenic MSCs and xenotransplant using patient MSCs in CD1- Foxn1nu mice. At a median follow-up of 42 months, patients with MSC-treated AVFs had reduced time to maturation with an increase in the vein diameter compared with controls. AVFs treated with allogenic MSCs in mice and pigs had an increase in M2- and M1-like macrophages with a decrease in VNH. Transcriptomic analysis of AVFs treated with allogenic MSCs in mouse and MSC xenotransplants of patients with successful AVFs showed decreased peroxisome proliferator–activated receptor gamma ( Ppar γ) and leptin receptor ( Lepr ) and increased latent transforming growth factor–beta–binding protein 2 ( Ltbp2 ). PPARγ was reduced in CD68 (+) cells from successful AVFs and allogenic MSC-treated mouse AVFs. Venous stenosis and VNH formation were mitigated in AVFs of mice with Ppar γ ablation in immune cells. Conditioned medium from MSCs of responders versus nonresponders had decreased proinflammatory genes, senescence-associated proteins, and monocyte-to-macrophage differentiation induced by phorbol 12-myristate-13-acetate. Periadventitial delivery of MSCs to AVFs promoted positive vascular remodeling through decreased inflammatory responses.

Radiologists play a key role in the management of renal masses, and it is important to understand the nonsurgical treatment options for solid renal masses, typical imaging findings after treatment, common complications, and methods to avoid pitfalls.

Background Recent guidelines have emphasized the use of medical management, early diagnosis, and a multidisciplinary team to effectively treat patients with critical limb ischemia (CLI). Previous literature briefly highlighted the current racial disparities in its intervention. Herein, we analyze the trend over a 14‐year time period to investigate whether the disparities gap in CLI management is closing. Methods and Results The National Inpatient Sample was queried between 2005 and 2018 for hospitalizations involving CLI. Nontraumatic amputations and revascularization were identified. Utilization trends of these procedures were compared between races (White, Black, Hispanic, Asian and Pacific Islander, Native American, and Other). Multivariable regression assessed differences in race regarding procedure usage. There were 6 904 562 admissions involving CLI in the 14‐year study period. The rate of admissions in White patients who received any revascularization decreased by 0.23% ( P <0.001) and decreased by 0.25% ( P =0.025) for Asian and Pacific Islander patients. Among all patients, the annual rate of admission in White patients who received any amputation increased by 0.21% ( P <0.001), increased by 0.19% ( P =0.001) for Hispanic patients, and increased by 0.19% ( P =0.012) for the Other race patients. Admissions involving Black, Hispanic, Asian and Pacific Islander, or Other race patients had higher odds of receiving any revascularization compared with White patients. All races had higher odds of receiving major amputation compared with White patients. Conclusions Our analysis highlights disparities in CLI treatment in our nationally representative sample. Non‐White patients are more likely to receive invasive treatments, including major amputations and revascularization for CLI, compared with White patients.

Key Points At 1 year after placement, 60% of hemodialysis arteriovenous fistulas (AVF) will develop venous neointimal hyperplasia (VNH) and subsequent venous stenosis (VS). Autologous adipose-derived mesenchymal stem cells may help reduce VS formation associated with hemodialysis AVF. There are no therapies available to prevent VS formation associated with hemodialysis AVF. Background Hemodialysis arteriovenous fistulas (AVFs) are the preferred vascular access for patients on hemodialysis. In the Hemodialysis Fistula Maturation Study, 44% of the patients achieved unassisted maturation of their fistula without needing an intervention. Venous neointimal hyperplasia (VNH) and subsequent venous stenosis are responsible for lack of maturation. There are no therapies that can prevent VNH/VS formation. The goal of this paper is to present the background, rationale, and trial design of an innovative phase 1/2 clinical study that is investigating the safety of autologous adipose-derived mesenchymal stem cells delivered locally to the adventitia of newly created upper extremity radiocephalic (RCF) or brachiocephalic fistula (BCF). Methods The rationale and preclinical studies used to obtain a physician-sponsored investigational new drug trial are discussed. The trial design and end points are discussed. Results This is an ongoing trial that will complete this year. Conclusion This is a phase 1/2 single-center, randomized trial that will investigate the safety and efficacy of autologous AMSCs in promoting maturation in new upper-extremity AVFs. Clinical Trial registration number : NCT02808208

Abstract The hemodialysis population continues to grow. Although procedures for dialysis have existed for >60 years, significant challenges with vascular access to support hemodialysis persist. Failure of arteriovenous fistulas (AVFs) to mature, loss of AVF and graft patency, thrombosis, and infection hinder long-term access, and add extra health care costs and patient morbidity. There have been numerous innovations over the last decade aimed at addressing the issues. In this study, we review the literature and summarize the recent evolution of drug delivery, graft development, minimally invasive AVF creation, and stem-cell therapy for hemodialysis access.

Significance Statement Expression of immediate early response gene X-1 ( Iex-1 ), also known as Ier-3, is increased in venous neointimal hyperplasia (VNH) and stenosis in hemodialysis arteriovenous fistulas (AVF). In a porcine model, 1α,25(OH) 2 D 3 , an inhibitor of Ier3, reduced VNH/stenosis formation. The 1α,25(OH) 2 D 3 released in the perivascular AVF space from poly(lactic-co-glycolic acid) nanoparticles embedded in a Pluronic F127 hydrogel (1,25 NP) reduced Ier3 gene and protein expression, MCP-1, CD68, HIF-1α, and VEGF-A immunostaining. Concomitantly, blood flow, lumen area, pulse wave velocity, and Young’s modulus increased, and neointima area, peak systolic velocity, and wall shear stress decreased in 1,25 NP–treated vessels. RNA sequencing analysis identified 242 genes involved in inflammatory and apoptotic pathways that had decreased expression in 1,25 NP vessels. Background Few therapies prevent venous neointimal hyperplasia (VNH) and venous stenosis (VS) formation in arteriovenous fistulas (AVF). Expression of the immediate early response gene X-1 ( Iex-1 ), also known as Ier3, is associated with VNH and stenosis in murine AVFs. The study aimed to determine if local release of Ier3 long-acting inhibitor 1α,25(OH) 2 D 3 from poly(lactic-co-glycolic acid) (PLGA) nanoparticles embedded in a thermosensitive Pluronic F127 hydrogel (1,25 NP) could affect VNH/VS formation in a large animal model. Methods Immediately after AVF creation in a porcine model of renal failure, 1,25 NP or vehicle control was injected into the adventitia space of AVF outflow veins. Scanning electron microscopy and dynamic light scattering characterized drug and control nanoparticles. Animals were sacrificed 3 and 28 days later for gene expression, immunohistologic, magnetic resonance imaging and angiography, and ultrasound analyses. Whole transcriptome RNA sequencing with differential gene expression analysis was performed on outflow veins of AVF. Results Encapsulation of 1α,25(OH) 2 D 3 in PLGA nanoparticles formed nanoparticles of uniform size that were similar to nanoparticles without 1α,25(OH) 2 D 3 . The 1,25 NP–treated AVFs exhibited lower VNH/VS, Ier3 gene expression, and IER-3, MCP-1, CD68, HIF-1α, and VEGF-A immunostaining, fibrosis, and proliferation. Blood flow and lumen area increased significantly, whereas peak systolic velocity and wall shear stress decreased. Treatment increased Young’s modulus and correlated with histologic assessment of fibrosis and with no evidence of vascular calcification. RNA sequencing analysis showed changes in the expression of genes associated with inflammatory, TGFβ1, and apoptotic pathways. Conclusions Local release of 1,25 NP improves AVF flow and hemodynamics, and reduces stenosis in association with reduction in inflammation, apoptosis, and fibrosis in a porcine model of arteriovenous fistula.

Background: Peripherally inserted central catheters (PICC) are occasionally placed in the great saphenous vein (GSV) and anterior accessory great saphenous vein (AAGSV) in patients with inadequate upper extremity veins or contraindications to upper extremity placement. Outcomes on the placement of PICCs in these veins are limited. Objectives: This study aimed to determine technical success and safety of GSV/AAGSV PICCs. Materials and methods: This is a retrospective study that reviewed all GSV/AAGSV PICC placements between January 2011 and December 2019. A total of 29 PICC placements procedures were identified. The electronic medical record was queried for demographic, procedural, and complication data. Technical success was defined by whether the vein could be accessed and a PICC could be placed. Catheter-associated infections, dislodgement or migration, malfunction, and PICC-associated thrombosis were recorded. Results: Technical success of placement was 100%. Twenty-one (72%) catheters were placed in the GSV in the mid to upper thigh and eight (28%) were placed in the AAGSV. The median PICC dwell time was 13 days with a range of 3–155 days. PICC-associated complications occurred after 11 (37.9%) placements. Line associated infection was the most common complication (17.2%). Conclusion: Due to a high complication rate, GSV/AAGSV PICC placement should be considered only when upper extremity or cervical PICC placement is not feasible or contraindicated.

ObjectiveThe purpose of this article was to provide a combined pathologic and radiologic review of previous pathologically diagnosed facial nerve “hemangiomas” to confirm that these lesions are most characteristic of venous malformations rather than neoplasms.Study DesignRetrospective radiologic, clinical, and histopathologic review of all patients with a previous pathologically diagnosed facial nerve hemangioma of the temporal bone who underwent computed tomography or magnetic resonance imaging (MRI) were included. A consensus radiologic review for characteristic features and pathologic analysis was performed.Materials and MethodsA panel of 4 neuroradiologists retrospectively analyzed CT and MRI exams for 11 facial nerve hemangiomas and provided a consensus agreement on the characteristic imaging features. Concurrently, two neuropathologists reevaluated archived tissue specimens from these lesions and applied additional immunohistochemical and histochemical stains including D240, CD31, smooth muscle actin (SMA), Verhoeff Van Gieson (VVG) and glucose transporter 1 (GLUT1).ResultsLesions were composed of dilated vascular spaces with a simple, CD31‐positive endothelial lining and a smooth muscle component. All lesions were negative for markers found in arterial and lymphatic malformations and infantile hemangiomas. They had characteristic radiologic features previously ascribed to facial nerve hemangiomas. Namely, these lesions are typically T1 isointense or hypointense and T2 hyperintense relative to cerebral cortex and heterogeneously enhance on MRI. Bony canal expansion and erosion, intralesional calcification, and intracranial extension are common.ConclusionsOn the basis of this radiologic and pathologic review, these lesions are best characterized as venous malformations.Level of Evidence4