View clinical trials related to Dialysis Access Malfunction.
Filter by:The continuous increase in the incidence of end stage renal disease and hemodialysis patients, has raised the interest of the vascular access scientific community and many researchers are currently investigating the potential mechanisms of arteriovenous fistulas (AVF) dysfunction. Roy-Chaudhury et al. were the first to suggest neointimal hyperplasia (NIH) as the main reason of AVF dysfunction and vessel negative remodeling as another important factor. First, Yamamoto et al. described 3 stenotic lesions categories of arteriovenous grafts (AVG) observed by ultrasonography: 1. vascular constriction type, 2. neointimal hyperplasia type, 3. mixed type (constriction and neointimal hyperplastic type). The main goals of this prospective observetional study are: - The characterization of AVF stenotic lesions by ultrasonography - The correlation of the stenotic lesion type with the outcomes of percutaneous transluminal angioplasty and the rate of reintervention.
The number of elderly hemodialysis patients is growing. Vascular access complications are a major determinant of the quality of life and health care costs for these vulnerable patients. The three different types of vascular access, i.e. autologous arteriovenous fistulas, arteriovenous grafts, and central venous catheters, have never been compared in randomized controlled trials. This project will deliver the much-needed evidence to determine the optimal strategy for vascular access creation in elderly hemodialysis patients in order to deliver better health care at lower costs.
The FLOW trial evaluates the follow-up of the vascular access for hemodialysis. In current clinical care, vascular access flow volume is periodically assessed to detect and treat asymptomatic stenosis. The FLOW trial will determine whether it is safe to abandon this practice of active surveillance. Vascular access stenosis will then be treated only when clinical problems of flow dysfunction occur during hemodialysis. The investigators expect that the intervention rate and medical costs will be reduced by 40% when correction of vascular access stenosis is triggered by clinically apparent access dysfunction rather than asymptomatic flow reduction.
Arteriovenous Fistula (AVF) is a surgically created circuit used for hemodialysis in patient with End Stage Renal Disease (ESRD). A functioning dialysis vascular access is critical to the delivery of life-saving hemodialysis (HD) treatment for these patients. Unfortunately, neointimal hyperplasia frequently occurs within the dialysis vascular access, resulting in stenosis, poor flow and thrombosis with loss of function. The cephalic vein forms the outflow conduit for radiocephalic (RC) and brachiocephalic (BC) AVF. At the perpendicular portion of the cephalic vein, the cephalic arch is often prone to developing hemodynamically significant stenosis. The prevalence of cephalic arch stenosis is reported to be 39% in brachiocepahlic and 2% in radiocephalic AVF. The current gold standard therapy for treatment of AVF stenosis is plain balloon angioplasty (BA). Paclitaxel coated balloon (PCB) angioplasty has also been shown recently to be superior to plain BA in the treatment of stenosis in dialysis vascular access. By releasing paclitaxel, which is an anti-proliferation drug, locally into the vessel wall during balloon contact, it will blunt the acceleration of intimal hyperplasia response, resulting in improved primary patency after angioplasty. The use of stent grafts for recurrent CAS has been demonstrated to increase patency of AVF compared to BA and bare stents. However, stent grafts are prone to edge restenosis that tend to occur within 5mm of each end of SG due to neointimal hyperplasia from the end of the stent migrating towards the center. We postulate that stent graft with PCB angioplasty of the stent edge is more effective than PCB alone in maintaining the patency of AVF with cephalic arch stenosis. Therefore, we aim to perform a randomized controlled trial to compare the 6-month unassisted patency rate of treatment of recurrent CAS with stent graft and PCB angioplasty of both stent edge versus PCB alone.
Drug-coated balloon (DCB) angioplasty has been shown to be superior to POBA in the treatment of stenosis in AVF. This is because the very intervention used to treat underlying stenosis by POBA can induce vascular injury and accelerate intimal hyperplasia, resulting in rapid restenosis and need for repeated procedure to maintain vessel patency. The anti-proliferative drug that is coated on the surface of balloon is released to the vessel wall during balloon angioplasty and blunt the acceleration of intimal hyperplasia response, resulting in improved primary patency after angioplasty. Additionally, unlike stents, DCB does not leave a permanent structure that may impede future surgical revision. Recent randomized control trials (RCT) have shown the superiority of paclitaxel durg-coated balloon (PDCB) over POBA in the treatment of stenosis in AVFs. In a large multicenter RCT, PDCB was demonstrated to result in a 6-month target lesion primary patency of 82.2% compared to 59.5% for POBA. However, concerns had also arisen recently in the use of PDCB. In large lower limb studies involving the use of paclitaxel devices, meta-analysis by Katsanos et al had revealed increased late risk mortality in patient that are treated with PDCB or paclitaxel-coated stent. Sirolimus drug-coated balloon (SDCB) is the new generation of drug eluting balloons that are available in the market. Compared to paclitaxel, sirolimus is cytostatic in its mode of action with a high margin of safety. It has a high transfer rate to the vessel wall and effectively inhibit neointimal hyperplasia in the porcine coronary model. The effectiveness of SDCB in patients with dialysis access dysfunction has been shown in a small pilot study in AVF stenosis and AVG thrombosis. SAVE AVF registry ams to assess the efficacy and safety of SDCB vs PDCB angioplasty.
This study will enroll end-stage renal disease (ESRD) patients on hemodialysis with a maturing arteriovenous fistula (AVF) for hemodialysis access. A study staff member will mark with indelible ink on each participant's skin the three sites on the upper extremity where the Eko CORE digital stethoscope will be used to take sound recordings. 9 recordings will be taken (3 at each site) once per week during weekly dialysis treatments.
Recent studies of paclitaxel DCB in the treatment of stenosis at dialysis vascular access have shown promising results. Paclitaxel, an anti-proliferation drug, is released during balloon inflation and potentially improve primary patency by slowing down NIH effect. However, meta-analysis have suggested that the use of paclitaxel in lower limbs have increased risk of death in patients. The effect of paclitaxel DCB on dialysis access however remains unknown. Hence, we aim to set up a database to track long-term treatment outcomes of patients treated with Paclitaxel DCB at SGH for their stenosed dialysis access
Hemodialysis vascular access dysfunction continues to be a major source of morbidity and mortality in patients with ESRD. Thrombosis is the most common cause of secondary vascular access failure Although intimal hyperplasia at the outflow vein is the most common cause of thrombosis, 20-40% of thrombosis may develop secondary without underlying anatomic abnormalities. Low-flow states secondary to low BP have been proposed to precipitate access thrombosis. In previous studies, lower pre- and post- dialysis SBP are associated with a higher rate of access thrombosis. Nonetheless, high blood pressure is also a well-known risk factor for arteriosclerosis, intimal hyperplasia, and thrombotic vascular events. In dialysis patients, the relation between blood pressure and thrombosis seems to be more complex, and few studies have delineated the effect of blood pressure in a systematic manner. In addition to the static component of blood pressure, blood pressure variability (BPV) is increasingly accepted as a novel risk factors for vascular disease. BPV is categorized as either long or short term. In dialysis patients, long-term BPV is typically defined on the basis of BP measurements taken at the start of hemodialysis (inter-dialysis BPV); short-term BPV is usually considered in terms of variability during hemodialysis (intra-dialysis BPV). BP variability is increased in ESRD patients and is associated with adverse outcomes. To the best of our knowledge, only one study by Cheung et al focused on intra-dialytic BPV, which found intradialytic hypotension to be a risk factor for access thrombosis. Nonetheless, access thrombotic events rarely occur during the dialysis session. It remained unclear that if inter-dialysis BPV is a more relevant factor for access thrombosis. Answer to this question is of clinical significance because the optimal BP target after PTA remained unknown. In this study, we aimed to investigate the effect of BP variability on the outcomes of hemodialysis vascular access, major cardiovascular events in maintenance hemodialysis patients. We also aimed to evaluate the determinants of BPV in hemodialysis patients, including medication, frailty, fluid status and autonomic function. The impact of autonomic function and frailty on the outcomes of vascular access and cardiovascular events will be evaluated as well.