Are high flow arteriovenous fistulas necessary?

Arteriovenous fistulas are the preferred vascular access for haemodialysis but may develop excessive flow. High-flow arteriovenous fistulas (HFAs) are common in practice, although their prevalence is difficult to establish because definitions and management strategies remain inconsistent. HFAs are associated with systemic complications, including high-output cardiac failure, left ventricular hypertrophy and pulmonary hypertension and local complications including ischaemia, dialysis inefficiency, aneurysmal degeneration and venous stenosis or occlusion. Assessment and management remain poorly defined, particularly in patients with mild or subclinical disease. This narrative review provides an updated overview of the definition, pathophysiology, clinical consequences, assessment and management of HFAs, with particular emphasis on continuing areas of uncertainty.