Comparison of warm ischemia versus no ischemia during partial nephrectomy on a solitary kidney

Background: The safe duration of warm ischemia during partial nephrectomy (PN) remains controversial. Objective: To compare the short- and long-term renal effects of warm ischemia versus no ischemia in patients with a solitary kidney. Design, setting, and participants: Using the Cleveland Clinic and Mayo Clinic databases, we identified 458 patients who underwent open (n = 411) or laparoscopic (n = 47) PN for a renal mass in a solitary kidney between 1990 and 2008. Patients treated with cold ischemia were excluded. Measurements: Associations of ischemia type (none vs warm) with short- and long-term renal function were evaluated using logistic or Cox regression models. Results and limitations: No ischemia was used in 96 patients (21%), while 362 patients (79%) had a median of 21 min (range: 4-55) of warm ischemia. Patients treated with warm ischemia had a significantly higher preoperative glomerular filtration rate (GFR; median: 61 ml/min per 1.73 m² vs 54 ml/min per 1.73 m ²; p < 0.001) and larger tumors (median: 3.4 cm vs 2.5 cm; p < 0.001) compared with patients treated with no ischemia. Warm ischemia patients were significantly more likely to develop acute renal failure (odds ratio [OR]: 2.1; p = 0.044) and a GFR <15 ml/min per 1.73 m² in the postoperative period (OR: 4.2; p = 0.007) compared with patients who did not have hilar clamping. Among the 297 patients with a preoperative GFR ≥30 ml/min per 1.73 m², patients with warm ischemia were significantly more likely to develop new-onset stage IV chronic kidney disease (hazard ratio: 2.3; p = 0.028) during a mean follow-up of 3.3 yr. Similar results were obtained adjusting for preoperative GFR, tumor size, and type of PN in a multivariable analysis. Limitations include surgeon selection bias when determining type of ischemia. Conclusions: Warm ischemia during PN is associated with adverse renal consequences. Although selection bias is present, PN without ischemia should be used when technically feasible in patients with a solitary kidney.