Rationale and Trial Design of MesEnchymal Stem Cell Trial in Preventing Venous Stenosis of Hemodialysis Vascular Access Arteriovenous Fistula (MEST AVF Trial)

Background: Hemodialysis arteriovenous fistulas (AVFs) are the preferred vascular access for patients on hemodialysis. In the Hemodialysis Fistula Maturation Study, 43.7% of the patients achieved unassisted maturation of their fistula without needing an intervention. Venous neointimal hyperplasia (VNH) and subsequent venous stenosis (VS) is 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 (AMSCs) delivered locally to the adventitia of newly created upper extremity radiocephalic (RCF) or brachiocephalic fistula (BCF). Methods: The rationale and pre-clinical studies used to obtain a physician sponsored investigational new drug trial (IND) are discussed. The trial design and endpoints are discussed. Results: This is ongoing trial which will complete this year. Conclusion: This is a phase 1 / 2 single center, randomized trial which will investigate safety and efficacy of autologous AMSCs in promoting maturation in new upper extremity AVFs.

Quantitative physical examination indicators to detect patients with stenosis at a high risk of thrombosis at hemodialysis vascular access sites: A retrospective case–control study

Background: Quantitative physical examination (PE) indicators, including palpable pulsatility length and outflow scores, can be used to quantify stenosis severity at hemodialysis vascular access sites. It is known that the risk of high-shear-related thrombosis is increased when the minimal luminal diameter (MLD) of stenosis decreases. At present, MLD is measured using sonography or angiography. This study sought to determine the relationship between quantitative PE indicators and MLD and report their diagnostic performance in detecting patients with stenosis at a high risk of thrombosis. Methods: We performed a retrospective case–control study using routinely collected data. We used the post-stenosis palpable pulsatility length (sPPL) and pulse-and-thrill based outflow score to assess the severity of AVF inflow and outflow stenosis, respectively. We recorded paired quantitative PE indicators and MLD before and after angioplasty in patients enrolled over a 4-month period. Results: A total of 249 paired PE indicators and MLD measurements were obtained from 163 patients. A receiver operating characteristic curve analysis showed that an MLD cutoff value of <1.55 mm and an MLD of <1.95 mm discriminated sPPL = 0 and PESOS (physical examination significant outflow stenosis)/1− of the outflow score, respectively, from all other measurements, with the area under the curve values of 0.8922 and 0.9618, respectively. With sPPL = 0 and PESOS/1− of the outflow score as diagnostic tools to detect inflow stenosis with an MLD of ⩽1.5 mm and outflow stenosis with an MLD of ⩽1.9 mm at vascular access sites, sensitivity = 86.00% and 88.46%; specificity = 97.67% and 92.11%; positive predictive values of 97.73% and 92.00% and negative predictive values of 85.71% and 88.61%, respectively, were observed. Conclusions: Our preliminary results showed that physical examination can potentially be a diagnostic tool in detecting patients with stenosis who are at a high risk of thrombosis at hemodialysis vascular access sites with high diagnostic accuracy.

New frontiers in vascular access practice: from standardized to patient-tailored care and shared decision making

Vascular access planning is critical in the management of patients with advanced kidney disease who elect hemodialysis for kidney replacement therapy. Policies put in place more than two decades ago attempted to standardize vascular access care around the model of optimal-i.e, arteriovenous fistula-and least preferred-i.e., central venous catheter-type of access. This homogenized approach to vascular access care emerged ineffective in the ever increasingly heterogeneous and complex dialysis population. The most recent vascular access guidelines acknowledge limitations of standardized care and encourage tailoring vascular access care based on patient and disease characteristics. In this article we discuss available literature in support of patient-tailored access care based on differences in vascular access outcomes by biologic and social factors-age, sex and race. Further, we draw attention to the overlooked dimension of patient-reported preferences and shared decision making in the practice of vascular access planning. We discuss milestones to overcome as requisite steps to implement effective shared decision making in vascular access care. Finally, we take into consideration local practice co-factors as major players in vascular access fate. We conclude that a personalized approach to hemodialysis vascular access will require dynamic care specifically relevant to the individual based on biological factors, fluctuating clinical needs, values and preferences.

Acute hepatitis post arteriovenous graft thrombectomy of hemodialysis vascular access

The following paper reports the case of a woman on in-center hemodialysis through an arteriovenous graft, who attended with an acute vascular access thrombosis. Post percutaneous thrombectomy, the patient presented a rare case of self-limited acute hepatitis secondary to the revascularization procedure. We explain the probable trigger for this complication, its pathophysiology, management, and evolution.

The role of stents in hemodialysis vascular access

Vascular access is the Achilles’ heel of dialysis therapy among patient with end stage kidney disease. The development of neointimal hyperplasia and subsequent stenosis is common in vascular access and is associated with significant morbidity. Percutaneous transluminal angioplasty using balloon inflation was the standard therapy of these lesions. However, the balloon-based approaches were associated with poor vascular access patency rate necessitating new inventions. It is within this context that different types of stents were developed in order to improve the overall dialysis vascular access functionality. In this article, we review the available literature regarding the use of stents in treating dialysis vascular access stenotic lesions. Further, we review the major clinical trials of stent use in different anatomic locations and in different clinical scenarios.

Arteriovenous Fistula Stenosis: A Case Report

Background: Arteriovenous fistula (AVF) has better rate of patency and lower rate of complication compared to other vascular access for hemodialysis. One priority to be concerned is access failure for hemodialysis access is common findings and correspond with high healthcare cost, morbidity and mortality. Objective: This case report aimed to elaborate the proper management of patient with arterio fistula stenosis. Case Illustration: A man, 64 years old, stage V CKD with AVF in his left arm for hemodialysis access was admitted to our hospital due to difficulty in cannulation during his last hemodialysis. He had AVF For Hemodialysis access for two years. About 1 month before, he undergone surgery for creation of AVF for hemodialysis access in his right arm, but AVF was failed to reach maturation. Based on vascular doppler ultrasound (DUS) done in AVF of the left arm revealed there was stenosis in the juxta-anastomosis site and cephalic venous stenosis. Angioplasty was done in anastomose AVF and implantation of venous stent in the left cephalic vein. Conclusion: For patients on hemodialysis, vascular access is considered as the lifeline. Complications related to Vascular access is associated with morbidity and reduced quality of life. Surgery often difficult to do as readily as a percutaneous approach. In more than 80% of hemodialysis access underwent percutaneous interventions, flow was successfully restored. Based on this success rate, it has replaced surgical revision as the treatment of stenosis AVF.

Multicenter Investigation of the Initial Hemodialysis Vascular Access and Its Related Factors in Hangzhou of China

Objective. To investigate the initial hemodialysis vascular access in Hangzhou and provide evidence for improving the use of autologous arteriovenous fistula by identifying factors associated with the choice of initial vascular access. Methods. We retrospectively studied the initial hemodialysis vascular access of 257 patients in five hemodialysis units in Hangzhou of China during a 21-month period (January 2018 to September 2019). A logistic regression was used to identify the risk factors of failing to use an arteriovenous fistula at the initiation of hemodialysis. Results. (1) 257 participants with mean age 67.65 ± 13.43 years old were reviewed, including 165 males (64.2%) and 92 females (35.8%). The etiologies of end-stage renal disease included diabetic nephropathy (37.35%), chronic glomerulonephritis (31.13%), hypertensive nephropathy (14.01%), and other diseases (17.51%). Only 51 patients (19.84%) received arteriovenous fistula, whereas the remaining 206 patients (80.16%) initiated dialysis with a central venous catheter. (2) Logistic regression analysis revealed that the independent risk factors for central venous catheter at the initial hemodialysis were age >70 years old ( OR = 4.827 , p < 0.01 versus ≤70 years old), chronic glomerulonephritis as the primary etiology ( OR = 2.565 , p < 0.05 versus nonchronic glomerulonephritis) and eGFR <8.5 mL/min/1.73m2 ( OR = 2.283 , p < 0.05 versus eGFR ≥8.5 mL/min/1.73m2). Conclusion. The proportion of patients using arteriovenous fistula as the initial hemodialysis vascular access in Hangzhou was still low. The choice of vascular access for the first hemodialysis was related to age, eGFR, and the primary etiology of end-stage renal disease. Increasing the proportion of planned vascular access and arteriovenous fistula at the initiation of hemodialysis is still our current goal.