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Percutaneous kidney biopsy (PKB) is an essential diagnostic tool. Kidney size has been traditionally considered a relative contraindication due to poor accessibility and risk of complications, To date, there is no consensus regarding the best approach in this setting.
Retrospective cross-sectional study at the Interventional Nephrology Department of the Instituto Nacional de Cardiologia Ignacio Chavez. Patients older than 16 years old who had kidney length of ≤ 8 cm and underwent a PKB of native kidneys from July 2019 to December 2022 were included. Sampling was performed in real-time guidance by ultrasound. For the comparative analysis, the Chi-square or Fisher’s exact test were used for qualitative variables, and the T-student or Mann-Witney U test for quantitative variables, according to their distribution.
25 patients were included, 19 women and 6 men. The mean age was 42.3 ± 18.04. The mean kidney length was 7.56 ±0.33 and the mean width was 4.2 cm. All patients received only one puncture, with an average of 12 glomeruli. The mean serum creatinine was 1.94 mg/dL . Minor complications occurred in 5 patients, perirenal hematoma 3 , hematuria in 1 , and hematoma plus hematuria in 1 patient. Histological examination showed FSGS in 36% of cases, lupus nephritis in 20%, other glomerular diseases in 16%, crescentic glomerulonephritis in 16%, and tubulointerstitial nephritis in 12%. Management was modified in 64% of cases. A bivariate analysis was performed for complications versus no complications based on clinical and ultrasound data, where statistical significance was found for complications with pre-biopsy DBP of 89 ± 5.80 mmHg (p>0.001). A pair-matching analysis found no correlation between kidney size with height and weight in the Mexican population.
PKB in small kidneys is a feasible and safe procedure when properly planned, providing an adequate sample in all cases, with an insignificant number of minor complications, and that is clinically relevant.