Single-Cell Analyses Offer Insights into the Different Remodeling Programs of Arteries and Veins.

Arteries and veins develop different types of occlusive diseases and respond differently to injury. The biological reasons for this discrepancy are not well understood, which is a limiting factor for the development of vein-targeted therapies. This study contrasts human peripheral arteries and veins at the single-cell level, with a focus on cell populations with remodeling potential.

The intricate cellular ecosystem of human peripheral veins as revealed by single-cell transcriptomic analysis.

The venous system has been historically understudied despite its critical roles in blood distribution, heart function, and systemic immunity. This study dissects the microanatomy of upper arm veins at the single cell level, and how it relates to wall structure, remodeling processes, and inflammatory responses to injury. We applied single-cell RNA sequencing to 4 non-diseased human veins (3 basilic, 1 cephalic) obtained from organ donors, followed by bioinformatic and histological analyses.

Chronic Kidney Disease Transdifferentiates Veins into a Specialized Immune-Endocrine Organ with Increased MYCN-AP1 Signaling.

Most patients with end-stage renal disease (ESRD) and advanced chronic kidney disease (CKD) choose hemodialysis as their treatment of choice. Thus, upper-extremity veins provide a functioning arteriovenous access to reduce dependence on central venous catheters. However, it is unknown whether CKD reprograms the transcriptome of veins and primes them for arteriovenous fistula (AVF) failure.

The Transcriptomics of the Human Vein Transformation After Arteriovenous Fistula Anastomosis Uncovers Layer-Specific Remodeling and Hallmarks of Maturation Failure.

Introduction: The molecular transformation of the human preaccess vein after arteriovenous fistula (AVF) creation is poorly understood. This limits our ability to design efficacious therapies to improve maturation outcomes.

Methods: Bulk RNA sequencing (RNA-seq) followed by paired bioinformatic analyses and validation assays were performed in 76 longitudinal vascular biopsies (veins and AVFs) from 38 patients with stage 5 chronic kidney disease or end-stage kidney disease undergoing surgeries for 2-stage AVF creation (19 matured, 19 failed).

Effect of Body Mass Index on Early Outcomes of Endovascular Abdominal Aortic Aneurysm Repair.

Background: This study compares the presentation, management, and outcomes of patients undergoing endovascular abdominal aortic aneurysm repair (EVAR), based on their weight status as defined by their body mass index (BMI).

Methods: Patients with primary EVAR for ruptured and intact abdominal aortic aneurysm (AAA) were identified in the National Surgical Quality Improvement Program database (2016-2019). Patients were categorized by weight status (underweight: BMI < 18.

Utility of Closed Suction Drains in Groin Incisions after Femoral Artery Exposure.

Background: Surgical groin wounds are at risk of delayed healing and infection, leading to costly and prolonged postoperative recoveries. This study assesses the use of closed suction drains (CSDs) as a wound care adjunct in groin incisions to prevent surgical site infections (SSI).

Methods: A single-center retrospective review was performed on 210 consecutive patients after vascular surgery with common femoral artery exposure from 2016 to 2021.

Vein morphometry in end-stage kidney disease: Teasing out the contribution of age, comorbidities, and vintage to chronic wall remodeling.

Background: Chronic kidney disease (CKD) is a highly comorbid condition with significant effects on vascular health and remodeling. Upper extremity veins are important in end-stage kidney disease (ESKD) due to their potential use to create vascular accesses. However, unlike arteries, the contribution of CKD-associated factors to the chronic remodeling of veins has been barely studied.

Echocardiographic changes after arteriovenous fistula creation in hemodialysis patients.

Background: Pulmonary hypertension (PH) is common in end-stage renal disease (ESRD) patients and is associated with increased all-cause and cardiovascular mortality in this group. There is scarce data on the long-term effect of arteriovenous fistula (AVF) creation on pulmonary hypertension (PH) and the reflected changes in echocardiographic measurements.

Materials And Methods: This is a retrospective study of 54 patients who underwent AVF creation between 2009 and 2014 and with echocardiographic evaluations before and after surgery.

Outcomes and role of shunting during carotid endarterectomy for symptomatic patients.

Objective: Shunt placement during carotid endarterectomy (CEA) has often been advocated to protect the ischemic penumbra in patients with symptomatic carotid stenosis. In the present study, we assessed the effect of shunt placement during CEA on postoperative stroke risk in symptomatic patients.

Methods: We queried the American College of Surgeons National Surgical Quality Improvement Program database (2016-2019) for CEA cases with complete CEA procedure-targeted data available.

Systemic Profile of Cytokines in Arteriovenous Fistula Patients and Their Associations with Maturation Failure.

Background: Systemic cytokines are elevated in patients with chronic kidney disease (CKD) and on hemodialysis compared with the general population. However, whether cytokine levels interfere with vascular remodeling, increasing the risk of arteriovenous fistula (AVF) failure, remains unknown.

Methods: This is a case-control study of 64 patients who underwent surgery for AVF creation (32 with AVF maturation failure and 32 matching controls with successful maturation).

COVID-19-related thrombotic complications experience before and during delta wave.

Objective: Hypercoagulability and thrombotic complications seen in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), as well as the associated pathophysiology, have been reported extensively. However, there is limited information regarding the factors related to this phenomenon and its association with the Coronavirus disease 2019 (COVID-19) Delta variant.

Methods: A retrospective review including patients admitted to a tertiary center with a COVID-19 positive test and at least one acute thrombotic event confirmed by imaging between June 2020 and August 2021 was performed.

A snapshot of early venous remodeling in a 7-day-old arteriovenous fistula.

Early remodeling of the arteriovenous fistula (AVF) determines maturation outcomes. However, the cellular response of the venous wall early after AVF creation remains largely enigmatic because of the lack of venous biopsies obtained shortly after anastomosis. This report presents a detailed immunohistochemistry analysis of a pre-access cephalic vein and the resulting seven-day-old AVF that required ligation due to steal syndrome.

The outcomes of a novel two-stage proximal brachial artery to proximal basilic/brachial vein arteriovenous graft extension for dialysis access.

Background: We describe a technique to mature a basilic/brachial vein in the mid-arm in preparation for a second stage loop proximal brachial artery to basilic/brachial vein arteriovenous graft (BBAVG). This can occur after a failed basilic/brachial vein transposition or a lack of adequate veins in the distal arm. This allows a mature vein to be used in an end-to-end configuration as an outflow to a BBAVG while preserving proximal vessels for the future.

An atypical case of hemodialysis access stent migration.

Endovascular stent fractures are commonly seen in arteries but are rare events in the venous system. Stents deployed in hemodialysis vascular accesses can fracture and migrate to proximal locations. Complications associated with stent fracture include in-stent stenosis and central vein stenosis.

Intimal Hyperplasia and Arteriovenous Fistula Failure: Looking Beyond Size Differences.

The development of venous intimal hyperplasia (IH) has been historically associated with failure of arteriovenous fistulas (AVF) used for hemodialysis. This long-standing assumption, based on histological observations, has been recently challenged by clinical studies indicating that the size of the intima by itself is not enough to explain stenosis or AVF maturation failure. Irrespective of this lack of association, IH is present in most native veins and fistulas, is prominent in many cases, and suggests a role in the vein that may not be reflected by its dimensions.

Inhibition of Lysyl Oxidase with β-aminopropionitrile Improves Venous Adaptation after Arteriovenous Fistula Creation.

Background: The arteriovenous fistula (AVF) is the preferred hemodialysis access for end-stage renal disease (ESRD) patients. Yet, establishment of a functional AVF presents a challenge, even for the most experienced surgeons, since postoperative stenosis frequently occludes the AVF. Stenosis results from the loss of compliance in fibrotic areas of the fistula which turns intimal hyperplasia into an occlusive feature.

The anatomical sources of neointimal cells in the arteriovenous fistula.

Neointimal cells are an elusive population with ambiguous origins, functions, and states of differentiation. Expansion of the venous intima in arteriovenous fistula (AVF) is one of the most prominent remodeling processes in the wall after access creation. However, most of the current knowledge about neointimal cells in AVFs comes from extrapolations from the arterial neointima in non-AVF systems.

A Multicenter Randomized Clinical Trial of Hemodialysis Access Blood Flow Surveillance Compared to Standard of Care: The Hemodialysis Access Surveillance Evaluation (HASE) Study.

Introduction: Arteriovenous (AV) access thrombosis remains 1 of the most troubling AV access-related complications affecting hemodialysis patients. It necessitates an urgent and occasionally complicated thrombectomy procedure and increases the risk of AV access loss. AV access stenosis is found in the majority of thrombosed AV accesses.

Vascularization of the arteriovenous fistula wall and association with maturation outcomes.

Background And Objectives: The venous vasa vasorum is the mesh of microvessels that provide oxygen and nutrients to the walls of large veins. Whether changes to the vasa vasorum have any effects on human arteriovenous fistula outcomes remains undetermined. In this study, we challenged the hypothesis that inadequate vascularization of the arteriovenous fistula wall is associated with maturation failure.

Transcriptomics of Human Arteriovenous Fistula Failure: Genes Associated With Nonmaturation.

Rationale & Objective: Improving arteriovenous fistula (AVF) outcomes requires better understanding of the biology underlying maturation or failure. Our current knowledge of maturation relies on extrapolation from other vascular pathologies, which does not incorporate unique aspects of AVF remodeling. This study compares the RNA expression of pre-access (native) veins and AVFs with distinct maturation outcomes.

Arteriovenous fistula outcomes in human immunodeficiency virus-positive patients.

Arteriovenous fistula (AVF) remodeling is an active area of research in vascular biology given the high rates of primary failure, complications, and cost burden for the health-care system. Comorbidities such as diabetes and different types of vascular disease are known to influence AVFs outcomes. However, little is known about the effects of immunosuppression, particularly human immunodeficiency virus (HIV) infection, on AVF primary failure and patency.

Assessment of left ventricular mass changes after arteriovenous fistula surgical banding in end-stage renal disease.

Left ventricular hypertrophy (LVH) is a multifactorial complication frequently seen in patients with advanced chronic kidney disease. An arteriovenous fistula (AVF) is the preferred method for hemodialysis access. Once functional, AVFs demonstrate better patency rates and fewer complications when compared to other forms of vascular access.

Fibrotic Venous Remodeling and Nonmaturation of Arteriovenous Fistulas.

The frequency of primary failure in arteriovenous fistulas (AVFs) remains unacceptably high. This lack of improvement is due in part to a poor understanding of the pathobiology underlying AVF nonmaturation. This observational study quantified the progression of three vascular features, medial fibrosis, intimal hyperplasia (IH), and collagen fiber organization, during early AVF remodeling and evaluated the associations thereof with AVF nonmaturation.

Similar degree of intimal hyperplasia in surgically detected stenotic and nonstenotic arteriovenous fistula segments: a preliminary report.

Background: Intimal hyperplasia has been historically associated with improper venous remodeling and stenosis after creation of an arteriovenous fistula. Recently, however, we showed that intimal hyperplasia by itself does not explain the failure of maturation of 2-stage arteriovenous fistulas. We seek to evaluate whether intimal hyperplasia plays a role in the development of focal stenosis of an arteriovenous fistula.

Comparison of Ultrasound-Guided Thrombin Injection of Iatrogenic Pseudoaneurysms Based on Neck Dimension.

Background: Ultrasound-guided thrombin injection (UGTI) of femoral artery pseudoaneurysms after endovascular procedures is an effective therapy. There is controversy in the literature regarding injecting pseudoaneurysms with short and/or wide necks. This article reports our experience in UGTI of pseudoaneurysms in 1 hospital regarding the efficacy of this treatment in all pseudoaneurysms regardless of the size of the necks.