RESUMO
OBJECTIVE: The results of preoperative ultrasound (pre-US) vein mapping for hemodialysis access creation can be affected by environmental and clinical factors, such as ambient temperature, acute illness, recent phlebotomy, and hypovolemia. These factors may inadvertently exclude otherwise viable veins as options for access creation. We hypothesized that repeating the ultrasound vein mapping immediately preoperatively after anesthesia administration (post-US) identifies additional veins not appreciated by pre-US, thereby altering the operative plan and producing more preferred accesses, particularly more forearm accesses. METHODS: We performed a retrospective cohort study of patients (N = 323) at one institution who underwent pre-US followed by creation of a permanent dialysis access (fistula or graft) between January 2008 and December 2013. By applying the Silva criteria to pre-US vein mapping reports, a preoperative surgical plan was established. There were 99 patients who underwent only pre-US (group I); an additional post-US was performed in 224 patients (group II). Using multivariable logistic regression, we tested the association of post-US (group II) with pre-US alone (group I) with a change in operative plan and placement of a more preferred access (ie, more distal and autogenous). We also analyzed access survival using multivariable Cox proportional hazards regression and determined maturation rates for accesses in groups I and II. RESULTS: In group II, there were more changes in operative plan after controlling for potential confounders (adjusted odds ratio, 1.96; 95% confidence interval, 1.18-3.25), and more preferred accesses were created (adjusted odds ratio, 1.82; 95% confidence interval, 1.01-3.27). In addition, more autogenous accesses were created in group II when initially only upper arm graft options had been identified (P = .01); overall, more forearm accesses were created in group II (P = .03). There was no significant difference in access maturation and patency in comparing accesses in group I and group II, despite creation of autogenous accesses in group II that are usually associated with higher rates of access failure. In fact, forearm radial-cephalic autogenous accesses created in group II had secondary patency rates of 91% at 2 years. CONCLUSIONS: Our study supports the hypothesis that the use of post-US in addition to pre-US leads to placement of more preferred accesses while maintaining maturation and patency rates. Ultrasound evaluation after anesthesia should be considered a step in the process of care for hemodialysis access creation to improve outcomes.
