AKI after Percutaneous Cryoablation of Kidney Tumors: A Retrospective Cohort Study

Background: Preservation of renal function is an important consideration in the management of renal tumors as decreased renal function is associated with a higher number of cardiovascular events, length-of-stay and overall mortality. Techniques for localized tumor management consist of radical or partial nephrectomy, and thermal ablation, which is considered the least invasive. To further assess the safety of thermal ablation, we evaluated the incidence of acute kidney injury (AKI) and need for hemodialysis after percutaneous renal cryoablation (PRC). Methods: This multicentric retrospective study involved two tertiary care centers between 2016 and 2022. Subjects were identified through a filter search of electronic medical records for any patient who underwent PRC for a renal tumor. A total of 311 patients were identified and the following data was collected: demographics, comorbidities, use of anticoagulation, laboratory data, tumor characteristics, and procedural data. AKI was identified by KDIGO definition of an absolute increase in serum creatinine (SCr), at least 0.3 mg/dL within 48 hours or by a 50% increase in SCr from baseline within 7 days. Baseline was defined as the lowest SCr within 1 year or most recent SCr if there was evidence of new baseline. Patients were excluded if there was no SCr recorded within 1 year prior to cryoablation or no SCr was obtained within 7 days post-cryoablation. Results: Among the cohort of 311 patients, only 44 met the inclusion criteria. 14 patients (32%) developed AKI, and 30 patients (68%) did not have AKI. Additionally, there were no patients who required hemodialysis following PRC. Of the patients that developed AKI at the primary center, all 8 of them had resolution of AKI within one month. Conclusion: PRC is a relatively safe and effective way to treat renal tumors while preserving kidney function. A major limitation of this study is the small number of patients with labs available pre- and post-cryoablation, which may be attributed to clinical stability of the patient precluding the need to obtain labs. Other limitations include lack of control group, short follow-up interval, and retrospective nature of study. These results are promising and warrant larger, randomized controlled trials to be conducted to validate the safety profile of PRC from a renal perspective.