Complications following 1053 percutaneous core renal mass biopsies: Risk Factors and Safety Assessment

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Percutaneous renal mass biopsy (RMB) is an effective diagnostic tool. Although morbidity of RMB is generally minimal, few studies have investigated risk factors and safety for complications. The purpose of this project is to evaluate patient, tumor, and technical factors associated with procedural complications following RMB.


Consecutive patients treated with percutaneous core RMB from 2003-2017 were identified. Institutional protocol allows RMB with INR ≤ 2.0, platelets > 25,000 and continuation of aspirin (ASA) therapy. Complications ≤30 days were graded using the Clavien-Dindo system. Logistic regression evaluated associations between complications and: age, gender, body mass index (BMI), Charlson Comorbidity Index (CCI), smoking status, pre-procedure labs (platelets, INR, hemoglobin), ASA, blood pressure during procedure, tumor diameter, Nephrometry score, biopsy needle size, US vs. CT guidance, number of needle passes, presence of trainees, and radiologist&[prime]s prior experience.


Of 1053 patients, 23 (2.2%) patients had procedural complications including: symptomatic hematomas 6(0.6%), gross hematuria 8 (0.8%), severe pain 4 (0.4%), UTI 4 (0.4%) and one patient each with hypotension, pseudoaneurysm and urinary retention. Major complications (≥Clavien 3a) were identified in 5 (0.5%) patients and 11 (1.0%) were admitted to the hospital. No patients had tumor seeding from biopsy. Age, BMI, gender, CCI, smoking status, platelet count, INR, hemoglobin, and blood pressure were not associated with complications (p=0.48, 0.09, 0.10, 0.33, 0.47, 0.16, 0.41, 0.46, 0.30). No associations were identified with complications and tumor diameter, Nephrometry score, needle size, type of radiologic guidance, or number of needle passes (0.30, 0.18, 1.0, 0.27, 0.10). RMB was performed in 401 (38%) patients on ASA and 51 (4.8%) with INR > upper limit normal. Risk was not increased in patients on ASA or for patients with INR 1.3-2.0, p=0.23 and 0.41, respectively. Trainee presence did not increase complication rate, p=0.24. Twelve radiologists performed at least 50 RMB, median 83 (range 54-136). Complications rates ranged from 0-2.3%, but no difference was identified between the most and least experienced radiologists, p=0.21. Risk was not increased during radiologist&[prime]s first 50 cases, p=0.23.


Renal mass biopsy is safe for patients with platelets > 25,000 or INR 1.3-2.0 and ASA did not increase complication risk. Number of needle passes, BMI, co-morbidities and radiologist experience were also not associated with complications.

Funding: none