The native arteriovenous fistula in 2007. Surveillance and monitoring.

In the past 5 years, some clinical trials have questioned the value of surveillance in managing vascular accesses. Although prolongation of access life span is an important end point, reduction of thrombotic events reduces patient risks resulting from loss of access patency. Most of the available evidence suggests that detection of stenosis and prevention of thrombosis is valuable. When a test indicates the likely presence of a stenosis, then venography or fistulography should be used to definitively establish the presence and degree of the stenosis. In most but not all cases, angioplasty should be performed if the stenosis is greater than 50% by diameter. The value of routine use of any surveillance technique for detecting anatomic stenosis alone, without concomitant functional assessment by measurement of access flow, venous pressure, recirculation or other physiologic parameters, has not been established. Stenotic lesions should not be repaired merely because they are present. If such correction is performed, then intraprocedural or periprocedural measurement of access flow (QA) or intra-access pressure should be conducted to demonstrate a functional improvement with a successful percutaneous transluminal angioplasty.