Paradox of Precision: More Parameters, Fewer Complications in Kidney Biopsy Outcomes

Background: Kidney biopsy is definitive for diagnosis of various glomerular diseases. Although minimal, this procedure is not done without risks. There is still no consensus regarding on best pre-biopsy protocol Methods: Retrospective analysis of all post-renal biopsy complications in a single center after a change to a more restrictive protocol, starting in November 2018 until December 2022. All biopsied patients met the pre-established parameters showed in table 01. If any parameter was out of range, a specific intervention was performed (transfusion, antihypertensive, dialysis). Complication rate was also analyzed within after the procedure: fall in hemoglobin levels,blood transfusion,need for hemodynamic intervention,refractory pain,nephrectomy,and death. Results: A total of 370 patients were included in the study, the majority being female [243 patients (65.6%)], and 88.9% of the biopsies performed on native kidneys. The age range varied from 4 to 76 years, with the majority between 14 and 53 years (81.6%). Regarding pre-biopsy parameters, the average hemoglobin was 11.3g/dL; platelets, 251,000/mm3; INR 1.09; systolic pressure 126mmHg and diastolic 79mmHg. In terms of glomerular filtration rate (GFR) and BUN, about 23.6% of patients had a GFR below 30mL/min, with BUN > 65, requiring pre-biopsy dialysis. Following this protocol, major complications occurred in only 4.86% of patients (10 patients with macroscopic hematuria, 6 patients requiring blood transfusion, 2 with intense pain). There were no instances requiring hemodynamic intervention, nephrectomy, or resulting in mortality. There was no association of complications with age, biopsy indication, or final diagnosis. Conclusion: A comprehensive renal biopsy protocol with well-defined parameters proved to be effective and feasible, with minimal complication rates. - Parameters Value Necessary intervention if required hemoglobin (g/dL) > 9,0 Transfusion platelets (mm3) > 100.000 Transfusion International Normalized Ratio (INR) < 1,4 Transfusion Systolic blood pressure (mmHg) < 140 antihypertensive medication 1 hour prior Diastolic blood pressure (mmHg) < 90 antihypertensive medication 1 hour prior Blood urea nitrogen (BUN) < 65 Dialysis