View clinical trials related to Arteriovenous Fistula.
Filter by:Arterio-Venous Fistula (AVF) is the most recommended vascular access for hemodialysis. Steal syndrome is a potential complication of AVF implantation and occurs secondary to diversion of the arterial flow of a limb to the venous system resulting in limb ischemia. Measuring wrist pressure compared to arm pressure before and after fistula implantation can be a suitable tool in predicting the possibility of Steal syndrome. In this study, the ratio of wrist to arm pressure and its relationship with Steal syndrome symptoms before and after fistula implantation are investigated.
The goal of this clinical trial is to compare plain old balloon angioplasty with sirolimus-coated balloon angioplasty in patients with an arteriovenous shunt stenosis. The main question we aim to answer is, how patency is affected by each of the randomised treatment modality.
Dialysis vascular accesses called arteriovenous fistulas ( AVF) are essential to ensure extra-renal purification by hemodialysis for patients with chronic end-stage renal disease. Complications of dialysis AVF cause significant morbidity and hospitalization. Dialysis AVF angioplasties are frequently used to treat stenosis, the 1st complication concerning them and which announces the complete thrombosis which may be the definitive loss of the AVF. Historically performed under X-ray, the progression in the quality of ultrasound scanners allows today to perform this procedure under echo-Doppler guidance and thus to avoid both radiation and the injection of iodinated contrast products and their complications. It is thus possible to preserve residual renal function, a situation with a better prognosis, or to help the maturation of the AVF without precipitating the patient towards dialysis. The procedure can then be less costly, requiring a much lighter infrastructure. The complication rates of ultrasound angioplasty remain poorly known because only a few series have been published. In addition, the evolution of the echo-Doppler parameters of the AVF is unknown during angioplasty and it is difficult to know which are the most reliable to distinguish during the procedure a "good angioplasty gesture" from an incomplete angioplasty to be continued. The proposed study would provide initial insight into the question posed.
This is a single-center, prospective, single-arm clinical study to evaluate the feasibility, safety, and performance of VenoStent's SelfWrap® Bioabsorbable Perivascular Wrap on arteriovenous fistulas (AVFs). All participants are chronic kidney disease (CKD) patients already receiving hemodialysis treatments that are referred for creation of a new arteriovenous fistula (AVF).
Multi-center trial to assess the feasibility and safety of the EchoMark LP and the EchoMark diagnostic ultrasound system for assessing AV fistula blood flow, diameter, and depth.
VAVASC trial is an observational multicentre study. The aim of this trial is to validate AVAS (arteriovenous vascular access stage) classification. The classification is used for determining which type of access is the most suitable for the patient on the basis of the patient´s vascular anatomy The methodology of this trial is to apply AVAS classification on patients who are indicated for creation of vascular access for hemodialysis. Data on these patients (vascular anatomy status, AVAS type, and predicted type of arterio venous access, demographic data etc.) will be than statistically analysed. Patients will then undergo creation of the selected arteriovenous access. They will be observed in terms of the access functionality. The follow up will be 1 to 3 years. The second aim of this study is to evaluate the relationship between AVAS classification and uninterrupted use of the created arterio venous access.
Patients with end-stage renal disease require permanent vascular access to enable safe and effective hemodialysis. An arteriovenous fistula (AVF), where a vein is mobilized and connected to an artery in the arm, is considered the gold standard and first choice for vascular access. After fistula creation, the vein is subjected to high pressure and flow, and undergoes remodeling. This includes the possibility of significant dilatation and intimal hyperplasia. Normal AVF flow required for effective dialysis is around 0.6 liters/min or 0.4-0.8 liters/min. However, in at least 20% of patients, excessive remodeling and dilatation of the fistula result in a high flow AVF with >2 liters/min. High flow fistulas significantly increase the risk for the development of high output cardiac failure, skin breakdown, bleeding, hand ischemia, and other systemic complications. In cases of high flow AVF, venous reconstruction procedures, banding and/or plication, are often required to limit venous diameter and flow. The longevity of this procedure is limited as the reconstructed segment remodels and re-dilates due to ongoing arterial pressure. Banding and plication are both procedures that are designed to increase resistance to flow. Banding is performed by wrapping a segment of polytetrafluoroethylene (PTFE) around the outflow tract of the fistula, or by placing a suture around the fistula near the arterial anastomotic area to create a narrowing. Fistula plication involves narrowing of a short segment of the proximal venous outflow tract, usually accomplished by suturing or stapling the fistula for 2-6 cm. One of the notable systemic effects of a hemodialysis AVF is an acute decrease in systemic vascular resistance with a simultaneous increase in venous return to the heart, and thus an increase of the cardiac output. Cardiac failure occurs more frequently in patients with an access flow QA>2 l/min and CPR≥20%. Another adverse systemic effect of AV fistulas is pulmonary hypertension. The increased flow volume to the heart from an AV fistula yields an increase in pulmonary pressures. This can limit pulmonary vasodilation and result in pulmonary hypertension.
The most common problem with haemodialysis arteriovenous fistulas (AVF) and arterio-venous grafts (AVG) is stenosis, which can lead to inadequate dialysis, and eventual access thrombosis. Conventional plain old balloon angioplasty (CBA) is associated with high recurrence rates of stenosis and repeated interventions. The advent of successful drug-eluting technology in the treatment of the coronary vascular bed and subsequent positive accumulating evidence in the peripheral arterial circulation has prompted the use of drug coated balloons (DCB) in the access fistula circuit for venous stenosis and in-stent restenosis. Recent studies suggest that DCBs may significantly reduce re-intervention rates on native and recurrent lesions. The restenosis process is in part or in whole the result of neo-intimal hyperplasia (NIH) and NIH is considered the main culprit in access circuit target lesion stenosis. NIH is the blood vessel's healing response to the barotrauma from the angioplasty process. A critical component of NIH is the cellular proliferative stage with mononuclear leucocytes identified as the primary inflammatory cell type involved. The rationale for drug elution is to block the NIH response with an anti-metabolite such as paclitaxel. It is important to emphasize that the role of drug elution in the treatment of vascular stenosis is not to obtain a good haemodynamic and luminal result but to preserve a good result obtained during POBA from later restenosis due to NIH and minimise reinterventions and readmissions to hospital for what is a frail population of patients. A meta-analysis performed by Khawaja et al. seemed to suggest that DCBs conferred some benefit in terms of improving target lesion primary patency (TLPP) in AVFs. An updated meta-analysis performed by our own institution recently reinforced that DCB appears to be a better and safe alternative to CBA in treating patients with stenosis within all haemodialysis circuits (fistulas and grafts) based on 6- and 12-months primary patency and increased intervention free period 5. However, this was not reflected in the largest RCT to date of DCB vs CBA in AVF with no superior target lesion patency demonstrated at six months and one and two years follow-up. Another recent meta-analysis found paclitaxel-coated balloons (PCB) showed no statistically significant improvement over conventional balloons in decreasing fistula stenosis in randomized controlled trials but were significant for cohort studies. Hence this shows the heterogeneity of the available data in the literature and the result is dependent on what studies you include in the review. Another reason why the outcome data is variable is that the high-speed blood flow in dialysis access circuits washes a large amount of the paclitaxel away from the target lesion soon after application. A measurement in swine showed that only 20%-30% of paclitaxel was taken up into the coronary artery wall in vivo 15-25minutes after PCB application. Furthermore, recent attention has been drawn to a possible increase in late mortality signal and lower amputation free survival in patients receiving DCB treatment with paclitaxel for peripheral arterial disease, although this suggestion has not been demonstrated in the data of DCB within the fistula circuit either at 1 or 2 years. In light of these concerns, attention has turned away recently from paclitaxel-based technologies to sirolimus coated platforms. Sirolimus, like paclitaxel, is a potent antiproliferative agent, which has been found to prevent restenosis in the coronary bed and more recently in the peripheral vasculature but to date has not been studied in AVF circuits The aims of the study is to determine the safety and efficacy of the MedAlliance SELUTION SLR 018™ DEB in the treatment of failing AV fistula due to conduit stenosis in patients undergoing renal dialysis.
The proposed clinical study is a prospective, non-randomized, multi-center, single-arm, observational, post-market surveillance (PS) study of the Ellipsys Vascular Access System in subjects eligible for arteriovenous (AV) fistula.
Arteriovenous fistulas (AVFs) are the preferred type of vascular access for dialysis, but many of them fail to mature. There are two techniques of creating AVFs either the traditional way with surgery( Surgical AVFs) or novel per-cutaneous technique Endo- AVFs. Investigators will pilot an randomized clinical trial of endo-AVFs and surgical AVFs at University of Alabama at Birmingham to determine the feasibility of patient recruitment, randomization, and retention. This pilot study will set the stage for a full-scale randomized clinical trial in future.