Minimal Effect of Cold Ischemia Time on Progression to Late-Stage Chronic Kidney Disease Observed Long Term After Partial Nephrectomy

ObjectivesTo assess the influence of cold ischemia on postoperative renal function and the new onset of late-stage chronic kidney disease during long-term follow-up after partial nephrectomy.MethodsA total of 131 patients with renal tumors who underwent partial nephrectomy and were followed up for ≥12 months were included in the present study. Renal function was analyzed using the estimated glomerular filtration rate (e-GFR).ResultsWe classified the subjects into 3 groups according to the length of cold ischemia time: group 1, 1-30 minutes; group 2, 31-60 minutes; and group 3, >60 minutes. Although the postoperative e-GFR was lower in group 3 than in groups 1 and 2, no significant difference was found among the 3 groups during long-term follow-up when preoperative CKD was absent. A cold ischemia time of ≥44 minutes significantly increased the probability of freedom from the new onset of an e-GFR of <45 mL/min/1.73 m2, but this difference was minimal. Multivariate analysis showed that the preoperative e-GFR and the relative decrease of e-GFR at 1 year after surgery were the significant factors determining postoperative renal function.ConclusionsA cold ischemia time of >44 minutes appears to be a threshold influencing the new onset of late-stage CKD; however, it was not a significant factor on multivariate analysis. Thus, renal hypothermia appears to prevent the deterioration of renal function long term after surgery for patients undergoing a longer ischemia time.