View clinical trials related to Arteriovenous Graft Stenosis.
Filter by: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 is associate 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 showed that DCB appears to be a better and safe alternative to conventional balloon angioplasty (CBA) in treating patients with HD stenosis based on 6- and 12-months primary patency and increased intervention free period. The Passeo-18 Lux (Biotronik Asia Pacific Pte Ltd (Singapore)) drug-coated balloon (DCB) is packaged with a low dose of paclitaxel. Recent studies have shown that low dose coating of paclitaxel with this DCB is useful for preventing restenosis, decrease lumen loss and target lesion revascularization in the peripheral vasculature6 but has not been tested in the dialysis access circuit.
Evaluation of the FLEX Vessel Prep system combined with angioplasty in the treatment of arteriovenous access stenosis.
A well-functioning vascular access is essential for providing adequate life-sustaining treatment in patients with end stage renal disease on maintenance hemodialysis. The preferred long-term vascular access is the arteriovenous fistula (AVF), which is created using the vessels of the patient by surgically connecting an artery with a superficial vein to increase the blood flow (Qa) in the venous system, which will dilate allowing the insertion of two needles, one to carry the blood to the dialyzer, and the other to return the cleansed blood to the body with the aid of a dialysis machine. Unfortunately, the high prevalence of vascular disease of the hemodialysis patients make difficult to create an adequate AVF in as many as 20 to 60% of the patients.In these persons, a valid alternative is the arteriovenous graft: in graft method an artery is surgically connected to a vein with a short piece of synthetic soft tube which is implanted under the skin. Needles are inserted in the graft during the dialysis treatment. Compared to an AV, however, graft is at higher risk of complications. The most frequent complication is thrombosis (i.e. the formation of blood clot inside the graft). Usually, thrombosis is the consequence of an underlying significant stenosis (i.e. a greater than 50% narrowing of the vessel or graft lumen by comparison with the lumen of a normal adjacent vessel or graft) and its hemodynamic consequences of decreasing the access blood flow (Qa) and/or increasing pressure within the graft. Therefore, all vascular access guidelines recommend regular noninvasive screening programs of grafts for timely identification of a stenosis associated with some type of functional or hemodynamic impairment, because its repair may prevent thrombosis and lengthen the useful life of the access. Screening methods include clinical monitoring and surveillance, which uses special equipment either to assess the hemodynamic consequences of stenosis by measuring Qa and static venous intra-access pressure ratio (VAPR) or to visualize the stenosis by means of duplex ultrasound (DU). Guidelines also state that there is insufficient evidence to prefer one method to another due to the lack of adequate comparative studies. The purpose of our study is to identify an optimal screening program for stenosis detection and elective repair by comparing the diagnostic performance for stenosis and incipient thrombosis of all the available screening tools in the same graft population
A prospective randomized trial comparing the efficacy of drug eluting balloon angioplasty versus conventional percutaneous transluminal angioplasty balloon for the treatment of hemodialysis arterio-venous fistula or arterio-venous graft stenoses in reducing late luminal loss and restenosis rates, while prolonging primary and secondary patencies.