Background: Bleeding is one of the most common complications after kidney biopsy. Amyloidosis is thought to be 1 of the risk factors, but this has not been confirmed in a large study. We performed this study to assess the risk of bleeding after kidney biopsy in patients with amyloidosis.
Study design: Retrospective study.
Settings & participants: 101 patients with and 188 patients without amyloidosis undergoing outpatient percutaneous kidney biopsy at a major medical center in the absence of abnormal partial thromboplastin time, prothrombin time international normalized ratio, or platelet count and/or uncontrolled hypertension.
Predictor: Clinical diagnosis of amyloidosis.
Outcomes & measurements: Post-kidney biopsy bleeding confirmed by means of imaging. Bleeding was defined as major if it required blood transfusion, hospital admission, or other invasive procedures and minor if none of these interventions were needed.
Results: Post-kidney biopsy bleeding was observed in 9.9% of patients with amyloidosis and 10.6% of controls (P = 0.8). Bleeding was major in 4% of patients with amyloidosis and 2.1% of controls (P = 0.4). Three patients from each group required blood transfusions and selective renal angiography. All except 1 patient from the control group underwent embolization.
Limitations: Retrospective data analysis and overall low event rate did not allow for independent risk-factor analysis.
Conclusions: The present study suggests that in the absence of a hematostatic disorder and/or uncontrolled hypertension, bleeding risk during kidney biopsy is not increased in patients with systemic amyloidosis. Kidney biopsy can be performed safely using the same screening criteria as for patients without amyloidosis.