Does Prolonged Warm Ischemia After Partial Nephrectomy Under Pneumoperitoneum Cause Irreversible Damage to the Affected Kidney?

PurposeWe determined the effects of warm ischemia time on the recovery of renal function after partial nephrectomy under pneumoperitoneum.Materials and MethodsIn this prospective study 37 consecutive patients who underwent laparoscopic partial nephrectomy or robot-assisted partial nephrectomy between June 2008 and May 2009 to remove a single cT1 renal tumor were evaluated using 99mTc-diethylenetriamine pentaacetic acid renal scintigraphy preoperatively, and at 3 and 12 months postoperatively.ResultsThe most significant reduction in the glomerular filtration rate of the affected kidney at 3 and 12 months after surgery (p = 0.018, p = 0.036, respectively) was seen for a warm ischemia time cutoff of 28 minutes. The glomerular filtration rate of the affected kidney was consistently and significantly reduced at 3 and 12 months postoperatively (−22.4% to −30.6%, p <0.001) in patients with a warm ischemia time greater than 28 minutes. In contrast, no significant glomerular filtration rate change was seen in patients with a warm ischemia time of 28 minutes or less. In terms of the contributional change of the affected kidney to total renal function, there is a trend toward a recovery after an initial decrease in both groups with a warm ischemia time greater than 28 minutes vs 28 minutes or less. On multivariate analysis warm ischemia time was a strong independent predictor of glomerular filtration rate reduction even 12 months after surgery (β = −1.3; 95% CI −1.8, −0.7; p <0.001).ConclusionsIf the warm ischemia time is greater than 28 minutes during laparoscopic partial nephrectomy or robot-assisted partial nephrectomy, the functional damage to the affected kidney progresses even up to 1 year after surgery.