Is Renal Warm Ischemia over 30 Minutes during Laparoscopic Partial Nephrectomy Possible? One-Year Results of a Prospective Study

Objective: To evaluate renal damage and impairment of renal function 1 yr after laparoscopic partial nephrectomy (LPN) with warm ischemia >30 min. Methods: From July 2004 to June 2005, 18 patients underwent LPN with warm ischemia time >30 min. Kidney damage markers (daily proteinuria and tubular enzymes) and renal function (serum creatinine, cystatin C, and creatinine clearances) were assessed on postoperative days 1 and 5 and at 12 mo. Glomerular filtration rate (GFR) was evaluated before surgery and at 3 mo. Renal scintigraphy was performed before the procedure, at 5 d and at 3 and 12 mo postoperatively. Statistical analysis was performed using the Student t test and logistic regression analysis. Results: In terms of kidney damage and renal function markers, the statistical analysis demonstrated that at 1 yr there was complete return to the normal range and no statistical difference between the values at the various time points. The GFR was not significantly different before and 3 mo after surgery. In terms of scintigraphy of the operated kidney, the values were 48.35 ± 3.82% (40-50%) before the procedure, 36.88 ± 8.42 (16-50%) on postoperative day 5 (p = 0.0001), 40.56 ± 8.96 (20-50%) at 3 mo (p = 0.003), and 42.8 ± 7.2% (20-50%) 1 yr after surgery (p = 0.001). Conclusion: Our results demonstrate that kidney damage occurs during LPN when warm ischemia is >30 min. This damage is only partially reversible and efforts should be made to keep warm ischemia within 30 min.