Risk factors for bleeding complications of percutaneous renal biopsy of native kidneys

Objective To retrospectively analyze the incidence of and risk factors for bleeding complications after percutaneous renal biopsy(PRB)of native kidneys.Methods The patients undergoing native PRB in Changhai Hospital of Naval Medical University(Second Military Medical University)from January 2017 to December 2018 were enrolled.Complete clinical and pathological data were collected.Blood routine and renal ultrasonography were conducted after PRB.Based on post-operative occurrence of bleeding complications in patients,the enrolled patients were divided into non-bleeding group(NBG),mild bleeding group(MBG,defined as the summation of the long and short diameter less than 5cm as well as the hemoglobin decrease less than 10% after PRB)and moderate to severe bleeding group(SBG,defined as gross hematuria,and/or hemoglobin decrease no less than 10%,and/or the summation of the long and short diameters no less than 5 cm and/or the need for transfusion/interventional therapy/surgery/death).The differences of clinical and pathological indices between the groups were compared.The risk factors of bleeding complications were analyzed by logistic regression model.Results A total of 357 patients were included in the study.The average age of patients was 47(34.0,61.0)and 51.2%(183 patients)of the patients were male.Among the patients,23 patients(6.4%)were complicated with acute kidney injury and 157 patients(44.0%)were complicated with hypertension.Overall,the rate of bleeding complications was 58.5%(209 patients),of which 105 patients(29.4%)developed severe bleeding complications,3 patients(0.84%)required transfusion and/or surgery intervention.Discharge time after PRB was not significantly different between NBG and MBG,suggesting that mild bleeding has no adverse effect on patients' short-term prognosis.Compared to the NBG,Patients in the SBG had lower levels of BMI,lower serum albumin,higher 24-hour urine protein,higher D-Dimer levels,higher rates of nephritic syndrome,longer hospital stay,higher serum urea nitrogen and higher estimated glomerular filtration rate(all P<0.05).After multivariable logistic regression analysis of related factors utilizing forward screen method,it was found that,BMI(OR=0.883,P<0.05),24-hour urine protein(OR=1.124,P<0.05),serum urea nitrogen(OR=1.078,P<0.05),D-Dimer levels(OR=1.204,P<0.05)and the long diameter of the kidney(OR=0.683,P<0.05)were independent risk factors for severe bleeding complications after PRB.Conclusions Post-biopsy bleeding complications aren't uncommon in patients with native PRB,but severe complications requiring transfusion or interventional therapy are rare.The patients with lower BMI,higher 24-hour urine protein,higher blood urea nitrogen,higher D-dimer levels and decreased kidney's long diameter have higher bleeding risks,who should be monitored more carefully.