Surgical Renal Ischemia: A Contemporary Overview

Purpose: Partial nephrectomy is being increasingly performed to treat renal cell carcinoma. Because warm ischemia is induced during many open and laparoscopic partial nephrectomy surgeries, its impact on postoperative kidney function has received renewed attention. We assessed the current state of knowledge pertaining to warm ischemic kidney injury and renal functional outcomes. Materials and Methods: A review of the literature from 1947 to 2007 pertaining to warm ischemic kidney injury was performed. Data from relevant animal and clinical studies were assessed and compared. Results: Animal studies have described the relationship between the duration of warm ischemia and the magnitude of subsequent renal dysfunction. However, direct translation of these data to clinical practice is limited by significant anatomical and physiological differences among species. Current clinical data support a safe warm ischemia time limit of 30 minutes in patients with normal preoperative kidney function. To date no scientifically rigorous clinical study has established a warm ischemia dose-response curve. Additionally, no algorithm exists to predict the risk of acute kidney injury and chronic kidney disease in patients undergoing transient warm ischemia. Conclusions: Clinical use of glomerular filtration rate measurement, kidney injury biomarkers and the application of glomerular filtration rate based renal functional diagnostic criteria may allow improved diagnosis, management and reporting of renal functional outcomes. Prospective, controlled clinical studies are much needed to accurately characterize the relationship between warm ischemia and renal dysfunction.