Warm Ischemia-Related Postoperative Renal Dysfunction in Elective Laparoscopic Partial Nephrectomy Recovers During Intermediate-Term Follow-Up

Purpose: To analyze the impact of warm ischemia time (WIT) on early postoperative and ultimate renal function after elective laparoscopic partial nephrectomy (LPN). Patients and Methods: One hundred and twenty-seven patients who underwent elective, ischemia-applied LPN were investigated in this study. The study patients were without stage 3 or greater chronic kidney disease (CKD) (estimated glomerular filtration rate [eGFR] <60 mL/min/1.73 m²) before LPN. Initially, the patients were grouped using the criteria of postoperative de novo stage 3 or greater CKD: Group A (n=104, eGFR ≥60 mL/min/1.73 m²) and group B (n=23, eGFR <60 mL/min/1.73 m²). The patients were also divided into two groups using 27.75 minute cutoff value obtained by receiver operating curve (ROC) analysis for WIT: Group 1 (n=69, WIT <27.75 min) and group 2 (n=58, WIT ≥27.75 min). The groups were compared with regard to demographic, perioperative, histopathologic, and renal functional outcomes. Results: The decreased preoperative eGFR (P<0.001) and increased WIT (P=0.007), operative time (P=0.015), diabetes mellitus (DM) rate (P=0.019) and pathologic tumor size (P=0.031) were significantly different in group B. Multivariate analysis determined that independent predictors of de novo stage 3 or greater CKD in the early postoperative period were preoperative eGFR (P<0.001), WIT (P=0.014), and DM (P=0.030); meanwhile, preoperative eGFR (P=0.006) was the only independent predictor at last follow-up. Decreased median postoperative eGFR (P=0.018) and percent preserved postoperative eGFR (P=0.001) were significantly different in the increased WIT group, as well as elevated median postoperative eGFR loss (P=0.001). After similar follow-up (26 vs 23.5 months, P=0.913), the increased and limited WIT groups were not significantly different with regard to final eGFR (P=0.936), final eGFR loss (P=0.749) and percent preserved final eGFR (P=0.690). Conclusions: In elective LPN, increased WIT plays an important role in renal functional loss in the early postoperative period. This functional loss, however, recovered after an intermediate term follow-up period, similar to that of patients undergoing limited WIT.