Optimizing renal biopsy: efficacy and safety of the ultrasound-guided tangential approach

To present the results of a series of outpatient renal biopsies performed with a tangential approach, as well as to conduct an analysis focusing on patient safety and the frequency with which sufficient material was obtained.

This retrospective observational study examined the pathology results and evolution of 244 patients referred for ultrasound-guided renal biopsy at a single center. In each biopsy, the needle was advanced in the cortex just below the renal capsule. The pathologist examined the fragments, counting the viable glomeruli obtained; additional punctures were performed if necessary, as long as Doppler ultrasound showed no bleeding. The patients remained at rest at the clinic, being discharged after a follow-up ultrasound evaluation and contacted one week later to investigate late adverse events.

Ten patients were excluded from the analysis, leaving a sample of 234 patients. The material obtained for diagnosis was considered sufficient in 95.73% of the procedures, partially adequate in 3.42%, and not very representative in 0.85%. Two patients (0.85%) had bleeding greater than 50 cm³ and were referred to the hospital emergency department. Both of those patients had a favorable evolution: one required only a period at rest, and the other required a blood transfusion, being discharged 48 h after the procedure.

The tangential approach to renal biopsy, with its high rates of safety and efficacy, representing a reliable diagnostic tool for renal and systemic diseases, should be the method of choice for obtaining adequate pathological specimens.