The Optimisation of Arteriovenous Fistula Vascular Access Outcomes for Haemodialysis

Abstract

End Stage Renal Failure, requiring renal replacement therapy, is delivered most commonly via haemodialysis (HD). The gold standard Vascular Access (VA) for HD is the arteriovenous fistula (AVF). However, it can be difficult to establish and maintain a mature AVF. A comprehensive vascular access service model was established with the aim of streamlining AVF care, allowing for the introduction of innovative solutions (over the subsequent years) to AVF pathologies and close observation of AVF experimental outcomes. This service resulted in an improvement in multiple VA outcomes and a reduction in VA expenditure. Innovative solutions focused on improving the reliability of the AVF through addressing known inflow, cannulation zone and outflow AVF pathologies were developed. We implanted an interwoven nitinol stent to approximate the optimal fluid dynamic geometry to treat stenoses of the inflow juxta-anastomosis (JXAS). We found acceptable patency results with no loss of AVFs in the long term results. A dynamic banding (DYBAND) technique was developed to treat excessive AVF inflow, allowing for band adjustment in concert with flow rate measurement, thus achieving the optimal band diameter for every individual AVF. The dysfunctional cannulation zone was addressed with cannulation zone stenting, allowing immediate puncture for dialysis. In a multi-centre study, we found acceptable outcomes and patency of AVFs to 4 years follow up, with a low rate of re-intervention. A pilot study with drug eluting stents in the AVF cannulation zone was performed to improve patency results. Whilst we were able to determine acceptable patency results, cessation of dual antiplatelet therapy in the medium-term post implantation was associated with stent thrombosis, hence limiting widespread adoption. During the study, a meta-analysis (Katsanos et al), determined a significant mortality risk associated with a commonly applied AVF first line therapy, drug eluting balloons (DEB). We performed a meta-analysis and demonstrated no such effect was present in AVF patients receiving a DEB. With increasing confidence from the aforementioned therapies, we combined these treatments as an adjuvant to AVF formation. The study demonstrated that timely, near universal AVF maturation was achieved, with all AVFs maintained utilising a low rate of re-intervention. The methods and results presented in this thesis demonstrates that for incident dialysis dependency, under the supervision of an RVAC, patients can have an AVF formed, matured and maintained for long term access