1:39 PM; Abstract No. 251 - Factors contributing to the success and major complication rate of ultrasound-guided native kidney biopsies

Abstract

To evaluate factors contributing to biopsy adequacy and complications from ultrasound-guided native kidney biopsy. In particular, the cortical tangential approach previously described for renal transplant biopsy (1) was evaluated. A retrospective review of the imaging and the electronic medical record was performed on all patients who underwent ultrasound-guided native kidney biopsy at our institution from October 1, 2002 to December 31, 2012. Demographic information and clinical data were collected, including laboratory values, blood pressure (BP) at the time of the biopsy, complications from the biopsy, and pathologic results. A sample was deemed adequate, indeterminate, or inadequate based on the number of glomeruli and the pathologist’s reported diagnostic confidence. The images and radiologic report from the biopsy were reviewed to determine use of the cortical tangential approach, patient position, number of passes, needle size and type, distance to kidney, left versus right, and presence of renal cortical thinning. Of 293 total patients, 9 (3.1%) experienced major complications (required transfusion or intervention) and 10 (3.4%) experienced minor complications (hematoma or hematuria not requiring transfusion or intervention) Patients with systolic BP >140 or diastolic BP> 90 had significantly more major complications (p<0.01). Glomerular filtration rate (p=0.10), cortical thickness (p=0.45), and distance to kidney (p=0.25) were not factors affecting complications. The use of the cortical tangential approach did not influence the complication rate (p=0.80) but was associated with significantly more glomeruli in the biopsy specimen (p<0.0001) and an increased overall adequacy of the sample (p<0.01). Medically lowering patients’ BP below 140/90 at the time of native kidney biopsy may reduce complications. The use of the cortical tangential approach may significantly improve the adequacy of the specimen.