Clamping renal artery alone produces less ischemic damage compared to clamping renal artery and vein together in two animal models: Near-infrared tissue oximetry and quantitation of 8-isoprostane levels

Purpose: To investigate renal ischemia injury during renal hilar clamping (artery alone versus clamping artery/vein together) by evaluating ischemic damage via two different modalities in animal models - near-infrared tissue oximetry and 8-isoprostane levels. Methods: Near-infrared renal oximetry measurements of Yorkshire swines (n = 4; 8 renal units) subject to hilar clamping were obtained at baseline, during warm ischemia (15- and 30-min trials) and after unclamping. Quantitation of 8-isoprostane levels is the second technique of quantitating interstitial fluid collected from a dialysis catheter placed through renal parenchyma of male Sprague-Dawley rats (n = 50) subject to hilar clamping during preclamp, clamp (either 15 or 30 min of hilum clamping), and post-clamp. Results: N ear-infrared tissue oximetry. In the 15-min trial, oxygen saturation decreased 6× faster with artery alone compared to artery/vein clamped together. In the 30-min trial, the decrease was 5× faster. Recovery of oxygen saturation with only artery clamped occurred more than 2× faster in the 15- and 30-min periods. Isoprostane. For 15-min clamp times, 8-isoprostane levels in the artery alone group demonstrated a 1.54 decrease in the artery clamped alone group (p = 0.006) versus artery/vein together: preclamp (11.47 and 11.63 pg/mL/g), clamp (14.61 and 17.70 pg/mL/g), and post-clamp (14.26 and 22.04 pg/mL/g). Conclusions: Renal ischemia injury from clamping the renal artery alone was significantly less than clamping artery/vein together demonstrated in two different techniques. Recovery of oxygen saturation was twofold faster, and mean post-clamp 8-isoprostane levels demonstrated a 1.54-fold decrease with clamping renal artery alone compared to clamping artery/vein together.