Comparison of urea recirculation and thermodilution for monitoring of vascular access in patients undergoing hemodialysis

Introduction It is important to monitor vascular access in patients with stage 5 chronic kidney disease receiving hemodialysis. Access recirculation can help to detect a need for intervention. Objectives: To compare urea recirculation with recirculation by thermodilution using blood temperature monitoring to predict a need for intervention of vascular access over a 6-month period. Methods: We analyzed urea recirculation and blood temperature monitoring simultaneously in 61 patients undergoing hemodialysis. During the 6-month follow-up, we recorded all cases of angioplasty or surgery (thrombectomy or reanastomosis). In line with previous studies, we considered a value to be positive when urea recirculation was >10% and blood temperature monitoring >15%. Receiver operating characteristic curves were constructed. Results: Mean urea recirculation was 9.5% ± 6.6% and mean blood temperature monitoring 12.9% ± 4.3% (p = 0.001). Urea recirculation >10% had a sensitivity of 80% and specificity of 78%. Blood temperature monitoring >15% had a sensitivity of 33% and specificity of 85%. During follow-up, 25% of patients developed need for intervention of vascular access. We found an association between vascular access dysfunction and urea recirculation. The Kaplan–Meier analysis confirmed an association between urea recirculation and risk of vascular access dysfunction (log rank = 17.2; p = 0.001). We were unable to confirm this association with blood temperature monitoring (log rank = 0.879; p = 0.656). Conclusion: Urea recirculation is better predictor of vascular access dysfunction than thermodilution.