Factors Affecting Renal Function After Open Partial Nephrectomy—A Comparison of Clampless and Clamped Warm Ischemic Technique

Abstract

To analyze factors impacting postoperative renal function after open partial nephrectomy using both the clampless and clamped warm-ischemic technique. We studied a cohort of patients who underwent clamped partial nephrectomy (n = 164) and clampless partial nephrectomy (n = 64) from March 2002 to March 2009 with ≥ 12-months follow-up. Clamped partial nephrectomy used hilar occlusion before resection. Clampless partial nephrectomy used focal radio frequency coagulation to facilitate hemostasis before resection, nonischemic dissection/resection with hydro-dissection, or sharp resection after local compression. Demographics, tumor characteristics/RENAL nephrometry scores, perioperative variables, and complications were compared between the two methods. Multivariable analysis was performed to identify factors predicting de novo estimated glomerular filtration rate <60. Patient characteristics were similar between groups. Mean RENAL score was greater in clamped (6.9) vs clampless (6.4, P = .026); complications (P = .430) and urine leaks (clampless partial nephrectomy 3.1% vs clamped-PN 7.3%, P = .360) were similar. Mean warm ischemia time (min) was 24.5 for clamped partial nephrectomy. De novo estimated glomerular filtration rate <60(%) at last follow up was 13.5 (clamped) vs 3.1 (clampless) (P = .071). Multivariable analysis of the entire cohort revealed increasing body mass index (OR 1.1, P = .042) and RENAL score (OR 1.71, P = .002) as being independently associated with development of postoperative de novo estimated glomerular filtration rate <60. Multivariable analysis of the clamped subgroup demonstrated increasing body mass index (OR 1.12, P = .028), RENAL score (OR 1.56, P = .010), and ischemia time (OR 1.15, P = .042) as independent factors associated with de novo estimated glomerular filtration rate <60. Body mass index and RENAL score were factors predictive of development of de novo estimated glomerular filtration rate <60 after partial nephrectomy, with increasing warm ischemia time also being predictive in clamped partial nephrectomy patients. Further investigation and long-term functional data are requisite.