Warm ischemic time’ and renal function preservation in robotic partial nephrectomy -evaluating its real impact

Abstract

Objective: To evaluate the effect of warm ischemic time (WIT) on future renal function (RF) after robotic partial nephrectomy (RPN) and secondarily, also to find out predictors of future RF after RPN. Method and materials: All patients who underwent RPN with normal pre-operative RF and normal contralateral kidney were included in the study except for those in whom one-year follow up was not completed. Patients were divided in four groups based on WIT (zero, <20minutes, 20 minutes to 30 minutes and >30 minutes). Comparison of demographic and perioperative parameters including follow-up up to one year were done. Univariable and multivariable analysis were done to detect significant correlation of RF with those parameters. Results: Total 198 RPN patients were included in the study. The four groups had comparable demographic data (age, gender, comorbidity, smoking, body mass index, pre-operative RF). Progressively increased WIT was significantly associated with increased tumour size (p=0.022), RENAL nephrometry score (p=0.003), operative time (p=0.004) and blood loss (p=0.046). Post-operatively, RF on first post-operative day (p=0.627), at one month (p=0.581) and at one year (p=0.378) had no significant difference between the four groups. Nine (4.5%) patients progressed to chronic renal disease. Pre-operative RF and perioperative complications only had significant correlation with one-year RF. Conclusion: Tumour size and RENAL nephrometry score significantly influenced WIT. Pre-operative RF and peri-operative complications were the only significant predictors of future RF and not the WIT.