Aettiiollogy and managementt off complliicatted upper lliimb prostthettiic vascullar artteriio-- venous grafftts ffor haemodiiallysiis

Abstract

Dialysis is not a complete substitute for native renal function. It only provides the bridge between ESRD and transplantation, in order to maintain and improve the patient’s physical condition, thus ensuring the best possible outcome after renal transplantation (Trivedi DD, 2011). End-stage renal disease is a major and growing healthcare problem associated with substantial costs. To facilitate adequate haemodialysis therapy, a reliable vascular access is mandatory and can be provided by creation of either an autologous arteriovenous fistula (AVF) or a prosthetic arteriovenous graft (AVG) (Allon M et al., 2011). Haemodialysis patients depend on a functional vascular access (VA) that is characterized by a superficial, low-resistance, high-flow conduit that allows for repetitive cannulation of the blood stream (O’Hare AM, 2013). The implementation of an all-autologous fistula policy to maximise the use of AVF over AVG has been advocated because AVF may have the best long-term patency, fewer complications and require less interventions once fully maturated. The AVF preference has been subsequently implemented in clinical guidelines (Allon M and Lok CE, 2010). Use of a synthetic prosthesis to construct on the upper arm an arteriovenous brachial-axillary graft or on the forearm a brachial-brachial loop graft is currently the recommended treatment alternative for patients who have exhausted all native fistulas access options (Akoh JA, 2009). Venous hypertension, arterial steal syndrome, and highoutput cardiac failure occur as a result of hemodynamic alterations potentiated by access flow (Padberg JR et al., 2008). Mechanical complications include pseudoaneurysm, which may develop from a puncture hematoma, degeneration of the wall, or infection. Dysfunctional hemostasis, hemorrhage, noninfectious fluid collections, and access-related infections are, in part, manifestations of the adverse effects of uremia on the function of circulating hematologic elements (Schutte WP et al., 2007). Uremic and diabetic neuropathies are common but may mask recognition of potentially correctable problems such as compression or ischemic neuropathy (Borman H et al., 2002). Adequate treatment of AV access dysfunction is a complex undertaking in which the interventional radiologist, vascular surgeon and nephrologist should cooperate with each other on a conjoint basis (Padberg JR et al., 2008). Stenosis of AV graft or primary AV fistula should be treated with percutaneous transluminal angioplasty (PTA) or surgical revision if stenosis is greater than 50% of the lumen diameter and is associated with hemodynamic, functional, or clinical abnormalities such as a previous thrombotic episode, abnormal physical findings, or decreased access flow (NKF-K/DOQI Clinical Practice Guidelines for Vascular Access. Clinical practice guideline 21). Therapeutic options of thrombosed arterio-venous graft include percutaneous or surgical thrombectomy, thrombolytic agents, and mechanical dissolution. The choice of technique to treat thrombosis should be based on the expertise of the center. If these modalities are successful, a graftogram can then be performed and detected stenoses treated with venoplasty or surgical revision. Failure to treat underlying stenosis will result in rapid repeat thrombosis (Mark R et al., 2006). Total or subtotal AV access excision should be performed for infected prosthetic arteriovenous graft when manifested by pus or fluid surrounding the entire conduit or when the conduit is completely thromboseded (Padberg JR et al., 2008).