Research Viewpoints Safety of Kidney Biopsy as an Outpatient Procedure

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Bonani M, Seeger H, Weber N, Lorenzen JM, Wüthrich RP, Kistler AD: Safety of Kidney Biopsy when Performed as an Outpatient Procedure. Kidney and Blood Pressure Research DOI 10.1159/000515439

For many decades elective percutaneous kidney biopsy in the prone position was uniformly performed during a short hospital stay, so that patients could be carefully monitored for adverse events. More recently, this procedure has been performed on an entirely outpatient basis, in patients deemed to be at low risk for such events. The actual biopsy procedure details and the required skills of the individual physician (nephrologist or interventional radiologist) performing the procedure are not different in the two settings (inpatient or outpatient). The overall comparative safety of kidney biopsy performed on inpatients or outpatients largely devolves around the risk factors for adverse events in the patients subjected to the procedure and the extent of post-biopsy monitoring. Transplant kidney biopsies generally have a lower risk of adverse events than kidney biopsies performed in native kidneys, regardless of the site.

Bonani and colleagues studied a cohort of kidney biopsies performed at a single center in native kidneys and kidney transplants on inpatients (n = 514; 233 native/281 transplant) or outpatients (n = 1,506; 430 native/1,076 transplant) between 2015 and 2019. All percutaneous biopsies were performed/supervised by 1 of 2 physicians (nephrologists) using a standardized protocol using ultrasound guidance and 16-G needles incorporated into semi-automated devices. The outpatients were monitored for adverse events for 4 h and were discharged if no macroscopic hematuria was observed or post-procedure US showed no “significant” bleeding (hematoma formation).

Major bleeding events occurred in 3.6 and 4.3% of native or transplant kidney biopsies, respectively, conducted at an inpatient site. Major bleeding events occurred in 0.7 and 1.1% of native or transplant kidney biopsies conducted at an outpatient site. No fatalities occurred. High-risk patients (amyloidosis, liver cirrhosis, bleeding disorder, inability to temporarily interrupt anti-platelet therapy, platelet counts <80,000/μL, hemoglobin <7 g/dL, BP >160/110 mm Hg) were preferentially biopsied at an inpatient site. Eighty-seven percent of the adverse bleeding events found in the outpatient biopsy cohort occurred during the 4-h observation period. Routine post-biopsy kidney ultrasound had no effect on management.

While this is a single-center, retrospective study, it involved a well-designed protocol as well as very experienced biopsy proceduralists. It supports the notion that in carefully selected patients a percutaneous kidney biopsy can be performed with reasonable safety on an outpatient basis with an observation period as short as 4 h. Routine post-biopsy ultrasound contributes nothing of a material nature to management.