MP257RISK FACTORS ASSOCIATED WITH BLEEDING COMPLICATIONS AFTER NATIVE RENAL BIOPSY

Abstract

Introduction and Aims: Bleeding is a well-recognised complication of percutaneous renal biopsy. Antiplatelet and anticoagulant agents are commonly being taken by patients requiring renal biopsy, and many centres discontinue them because of a perceived higher risk (or greater severity) of post-procedure bleeding. This study was designed to examine factors associated with complications after percutaneous renal biopsy. Methods: We included consecutive adult patients undergoing native renal biopsy in the Glasgow Renal and Transplant Unit from2000 to 2014. Data relating to indication for biopsy and complications were recorded on the electronic patient record contemporaneously. Biopsies were performed bymore than 50 operators over the 15 years using real time USS guidance and 16G spring loaded Bard Max Core biopsy guns. To minimise bleeding risk, the following pre-biopsy parameters are used as a guide: prothrombin time (PT) <15 seconds; platelet count ≥100 x 109/L and blood pressure controlled. Aspirin was routinely continued but clopidogrel and warfarin stopped. Bleeding times were not checked and pro-coagulants were not administered. Data were extracted fromthe electronic patient record for biopsy indication, pre-biopsy haemoglobin, platelet count, PT, estimated glomerular filtration rate (eGFR), serum creatinine, urinary protein creatinine ratio, body mass index (BMI), use of antiplatelets or anticoagulants and diagnosis. We defined major complication post-biopsy as need for blood transfusion, surgical or radiological intervention, or death. Binary logistic regression analysis was used to assess factors associated with increased risk of major complication. Results: 2619 patients underwent native renal biopsy (1536 elective, 1083 emergency). 57.3% were male and the average age was 57 (SD 17) years. 508 were conducted as day case procedures. Overall, the rate of major complication was 2.1%, which is similar to the few other large contemporary series in the literature. 47 patients required transfusion (1.8%), 10 patients underwent embolisation (0.4%), no patient required nephrectomy and 1 patient died as a result of a significant late bleed (day 12 post-biopsy). Major complications were more common in those undergoing emergency compared with elective renal biopsy (3.4% versus 1.2%, p<0.001). Aspirin was being taken at time of biopsy in 342 of 1564 patients with no significant increased risk of bleeding (p=0.93). Pre-biopsy platelet count, PT and blood pressure were not associated with risk of bleeding. Increased age and decreased estimated glomerular filtration rate were associated with increased risk of major complication (HR 1.025 (1.007-1.043), p=0.006; 1.034 (1.05-1.018), p<0.001 respectively). BMI data were available for 546 patients, with no increased risk of bleeding in 207 patients classified as obese (BMI >30). In 339 patients with vasculitis, the complication rate was higher: 5.0% suffered a major complication, the majority of whom required blood transfusion. Conclusions: The risk of major bleeding following native renal biopsy in the modern era is low. Complications are relatively more common when biopsy is conducted as an emergency, which has implications for obtaining informed consent. Obesity does not appear to be a risk factor for bleeding. Our data support the strategy of not stopping aspirin before renal biopsy.