#2302 Bleeding risk stratification following kidney biopsy using “MAJOR BLEEDING RISK SCORE”

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Background and Aims Kidney biopsy (KB) is the gold standard in diagnosing the majority of kidney diseases. While generally KB is a safe procedure, a complication rate of 6-8% has been reported, mainly bleeding. Halimi et al. proposed “The Major Bleeding Risk Score” (MBRS) identifying 11 risk factors (out of a maximum of 41 points) associated with the likelihood of major complications (such bleeding requiring transfusion, arteriography, nephrectomy or death). Method In this retrospective study, we analyzed 358 native KB conducted between 2017 and 2022 by the interventional nephrology team in a tertiary hospital. Following the application of the MBRS, 273 KB were finally included to validate the score within our cohort. Results We analyzed 273 KB, 46.5% were male, with a mean age of 53.6 ± 18.5 years. The majority of KB were performed on the left kidney (82.4%), with an average of 2.1 ± 0.7 cylinders and 12.33 ± 6.27 glomeruli. The MBRS stratified patients into three risk groups: G1 for scores from 0 to 9 points (36.6% KB), G2 for scores between 10 to 19 points (38.8% KB) and G3 for scores from 20 to 29 points (24.5% KB). Eleven patients (4%) had major complications (0.3% in G1, 1.5% in G2 and 2.2% in G3). The risk of bleeding increased proportionally with risk stage (G1 1% vs G2 3.8% vs G3 9%, p=0.037). Patients who experienced a complication after KB had a significantly higher MBRS than patients who did not develop complications (19 ± 5.23 points vs 13 ± 7.19 points, p=0,01). Patients who developed complications associated anaemia, thrombopenia and lower BMI more frequently than patients who did not develop complications (23.6 ± 5.9 vs. 27.3 ± 5.4, p=0.03). The pathology with the highest bleeding was thrombotic microangiopathy [OR 10,54 (2,39-46,51)]. Conclusion The MBRS adequately stratifies patients according to bleeding risk and could be a valuable tool in the clinical practice guiding the decision to proceed with the kidney biopsy.