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

The safe duration of warm ischemia during partial nephrectomy (PN) remains controversial.

To compare the short- and long-term renal effects of warm ischemia versus no ischemia in patients with a solitary kidney.

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.

Associations of ischemia type (none vs warm) with short- and long-term renal function were evaluated using logistic or Cox regression models.

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: 6 ml/min per 1.73 m(2) 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 m(2) 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 >or=30 ml/min per 1.73 m(2), 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.

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.