Preoperative volume status in vascular access creation: A despised influence?

Background: The most common causes of early primary failures of a vascular access (VA) is related to small caliber vessels. Weight gain between dialyses expands both extracellular and blood volume, which may lead to rises in intravascular filling and vessels caliber. If patients presented after weekend, their weight and probably volemia would be higher. We hypothesized that preoperative volume status may influence vascular filling and vessels diameter with a significant impact on VA outcomes. Methods: A clinical, prospective, randomized, open-label, single-center within-patient physiological crossover evaluation trial. Inclusion criteria: age 18–80 years, under regular hemodialysis (three per week) Exclusion criteria: >3 sessions/week, heart failure (HF), and acute pulmonary edema on the previous year. Before the last-week session, patient’s clinical parameters were recorded. BIA and ultrasound vascular mapping were performed. After this first evaluation, dry weight was increased 0.5 kg, and after weekend, the same protocol was conducted. Primary end point was to compare vein diameters. Results: One hundred twenty-six vessels were evaluated (84 veins and 42 arteries) from 21 patients. Mean age was 69 ± 10 years and 52% female. Other than humeral arterial blood flow, every parameters evaluated through ultrasound mapping significantly increased ( p < 0.05), however, most patients had a mild-moderate OH (86%–90%). Patient-level paired analysis confirmed a significant increase in mean venous diameter after volume expansion ( p = 0.002). No complications were reported. Conclusions: Preoperative volume status appears to be an underrecognized and potentially modifiable determinant of vascular access conditions. Mild preoperative volume expansion was associated with increased venous diameter, a surrogate for AVF feasibility and maturation. BIA and lung ultrasound may be future tools that combined to vascular ultrasound could be a safe and effective way to optimize and evaluate preoperative conditions to improve VA outcomes. Future multicenter prospective studies should assess whether preoperative volume optimization translates into improved AVF creation, maturation, and long-term patency outcomes.