Pre-operative Assessment for Arteriovenous Fistula Placement for Dialysis.

Native AV fistulas are considered to be the best VA for most dialysis patients. A careful preoperative process of care is essential to maximize the proportion of fistulas that achieve adequacy for dialysis. An individualized and timely evaluation of patients starts early with the identification of risk factors, followed by a physical examination which should be complemented by ultrasound vascular mapping in most cases. Vascular mapping includes any technique that leads to information on patient's inflow and outflow anatomy (± hemodynamics) as they relate to arteriovenous access creation and may predict maturation. There is increasing evidence favoring the utilization of preoperative Doppler ultrasound which is recommended in all patients by NFK-KDOQI Guidelines. It allows noninvasive evaluation of both structural and functional aspects of vessels that play an important role in access maturation. Its major limitation is the relative inability to assess central vein patency. Although conventional venography is still the gold standard to evaluate central veins, it provides otherwise limited information and can incur serious adverse effects related to its invasive nature and contrast use. Alternatives to these two imaging techniques are rarely used, especially because of their higher costs and low availability.