Routine Ultrasound Studies of the Vascular Access in a Dialysis Center: A Review

Abstract

The establishment and maintenance of vascular access in end‐stage renal disease provides a greater challenge. Adequate dialytic therapy requires reliable, long‐term access to the blood circulation. Vascular access remains the Achilles' heel of chronic hemodialysis; complications are costly for the patient and society. Vascular access failure is the most frequent cause of hospitalization for patients with chronic renal disease. The general goal was to prevent thrombectomies, thus preventing hospitalizations and reducing cost, and most importantly, saving the patient's access and increasing the survival rate of the graft or fistula. A protocol to evaluate the vascular accesses at the dialysis centers where our patients are dialyzing was implemented. The patients are evaluated before their dialysis treatments, every 2 months if they have a graft and every other visit (4 months) if they have a fistula. New patients will be evaluated every visit by the vascular technician. The protocol (US Vascular Access Protocol) also has attention parameters and depth considerations. The attention parameters refers to blood flows and reductions in size. For example, for a fistula, a normal flow will be 400 mL/min or above, an alert value will be 390 mL/min or below, and a reduction in size of 1.9 mm or below will also be an alert value for the fistula (Table I). Depth considerations relate to how deep the access is, for example 2–3 mm is ideal to cannulate, 8 mm and above make cannulation impossible (Table II). Patients with vascular problems are then referred to the vascular surgeon or, as mostly, are referred to interventional radiology. We have found that these Doppler reports are very accurate, and after almost a year, doing these tests at the dialysis center, many accesses have been saved, and dialysis quality has improved in those patients by resolving issues causing re‐circulation, stenosis, etc. In conclusion, we need to continue evaluating this program, but the preliminary reports show that by using the Doppler studies prophylactically, dialysis accesses can be saved or their use prolonged, thereby saving costs and reducing the need for future sites for the patient. And, in some cases, improving dialysis adequacy. Attention parameters Normal values Alert values Fistula Access volume flow (mL/min) ≥400 0–390 Reductions (mm) ≥2.0 0–1.9 Graft Access volume flow (mL/min) ≥600 0–590 Reductions (%) 0–49 50–100 Depth considerations 2–3 mm Ideal and easy to cannulate 4–5 mm Is acceptable 6–7 mm Increases difficulty of cannulation and increases vessel wall damage ≥8 mm Makes cannulation difficult‐to‐impossible, causes significant wall damage and infiltrations, requires longer cannula