Association of Kidney Biopsy Needle Gauge with Post-Procedure Complications and Biopsy Adequacy.

Abstract

Background: While a larger needle gauge can provide additional kidney tissue for diagnosis, it might also predispose to greater complication risk. Here, we evaluate the safety and diagnostic adequacy of kidney biopsies in patients who underwent a biopsy with various needle sizes.

Methods: We evaluated rates of biopsy-related complications and adequacy between participants who underwent biopsy with 16G vs 18G needles. We assessed safety using a composite outcome of blood transfusion, angiographic intervention, hemoglobin drop of at least 2 g/dl, or at least a medium sized hematoma after kidney biopsy. We defined adequacy as the number of glomeruli available for diagnosis.

Results: Among 781 participants included in the analysis, 665 (85%) were performed using a 16G needle and 116 (15%) were performed using an 18G needle. We observed similar odds of complications in the 16G group as compared to the 18G group in univariable analysis (odds ratio, 1.56 (95% confidence interval, 0.81, 3.01)); however, there were higher odds of complications in the 16G group in both multivariable analysis adjusting for pre-biopsy bleeding risk factors (2.40 (1.16, 4.93)) and propensity score weighted analysis (2.92 (1.28, 6.67)). As compared to 18G needle, 16G biopsy needle was associated with more glomeruli obtained (13 [9,19] vs. (11 [6,15], P<0.001). The higher number of glomeruli in 16G group persisted after multivariable adjustment (5.06 (2.52, 7.59)) and propensity score weighted (4.39 (0.37, 8.42)) analyses.

Conclusions: Participants with kidney biopsies performed with a 16G needle tended to sample more glomeruli and had similar complications on univariable analysis but higher complications when adjusting for pre-biopsy risk factors. This indicates that larger needle gauge provided more tissue for diagnosis, but clinicians appropriately avoided its use in those at higher risk of complications. Our findings suggest that use of a 16G needle improves diagnostic yield but carries a higher adjusted risk of complications, underscoring the importance of individualized needle gauge selection.