Purpose: Renal biopsy-related arteriovenous fistula (RB-AVF), although usually asymptomatic, may sometimes result in serious clinical implications. The aim of the study was to prospectively evaluate the incidence of RB-AVF in native kidneys, together with the assessment of hemodynamic characteristics and the impact of the histopathological results of biopsy.
Methods: The study included 138 patients (age 46.2 ± 15.2; 70 F, 68 M), who underwent percutaneous renal biopsy (PRB) of the native kidney. In all patients, 2D and color Doppler ultrasound was performed 24 h after PRB in order to exclude RB-AVF.
Results: Bleeding complications in the form of hematomas were found in 136 patients (98.55 %), and 23 cases of RB-AVF were observed (16.67 %). RB-AVF group had an increased maximal hematoma diameter and reduced number of glomeruli in PRB. The segmental arteries supplying the fistulas are characterized by higher maximum flow velocity (FV) and a lower resistance index (RI) compared to the normal segmental arteries (difference 45.9 ± 20.0 cm/s and 0.252 ± 0.104, respectively). In the ROC analysis, RI ≤ 0.524 allowed to detect RB-AVF with a sensitivity of 91 % and specificity of 100 % (AUC 0.998, p < 0.001). In approximately 39 % of RB-AVF cases, 2D ultrasound detected a hyperechogenic ischemic area between the fistula and the renal capsule.
Conclusions: Arteriovenous fistula is a quite frequent complication of native renal biopsy and can cause ischemia in the renal parenchyma detected by ultrasound. The arteries supplying the fistula are characterized by an increased flow velocity and reduced resistance index.
Keywords: Arteriovenous fistula; Renal biopsy; Resistance index.