Risk of bleeding after percutaneous native kidney biopsy in patients receiving low-dose aspirin: a single-center retrospective study.

Background: Although discontinuation of antiplatelet agents at least 5 days before kidney biopsy is commonly recommended, the evidence behind this practice is of low level. Indeed, few non-randomized studies previously showed an equivalent risk of bleeding in patients receiving aspirin therapy.

Methods: We conducted a single center retrospective study comparing the risk of complications after percutaneous native kidney biopsy in patients who received low-dose aspirin (ASA) within 5 days from biopsy and those who did not. The main outcome was the difference in the incidence of major complications (red blood cell transfusion, need for selective arterial embolization, surgery, nephrectomy). Secondary outcomes included difference in minor complications, comparison between patients who received ASA within 48 h or within 3-5 days, identification of independent factors predictive of major complications.

Results: We analyzed data on 750 patients, of whom 94 received ASA within 5 days from biopsy. There were no significant differences in the proportion of major complications in patients receiving or not receiving ASA (2.59% and 3.19%, respectively, percentage point difference 1%, 95% CI - 3 to 4%, p = 0.74). Groups were also comparable for minor complications; among patients receiving ASA, there were no differences in major bleeding between those who received ASA within 48 h or 3-5 days from biopsy. Significant baseline predictors of major bleeding in our cohort were platelet count lower than 120*10/microliter, higher diastolic blood pressure and higher blood urea.

Conclusions: Treatment with low-dose ASA within 5 days from kidney biopsy did not increase the risk of complications after the procedure.