Sildenafil improves immediate posttransplant parameters in warm-ischemic kidney transplants: Experimental study

Objective. To evaluate in an experimental model the effects of the PDE5 inhibitor sildenafil on kidney grafts autotransplanted after a period of 45 minutes of warm ischemia and 60 minutes of hypothermic pump perfusion. Methods. Nine laboratory large-white pigs were divided into two groups. Group A (n = 4): oral dose of 100 mg sildenafil was administered 1 hour before the surgery. Group B (n = 5): no sildenafil given. Right single nephrectomy was completed after a 45-minute period of warm ischemia by complete vascular clamping. Before the autotransplant, all kidneys were submitted to a 60-minute period of hypothermic pulsatile perfusion. Renal flow, arterial pressure, and renal vascular resistance were recorded in real time for 60 minutes after autotransplant. Nitric oxide levels were determined in blood samples of the renal vein at predefined intervals. Optical and electronic microscopy was performed on all organs at the end of the procedure. Results. Renal vascular flow was significantly higher and renal vascular resistance significantly lower in the sildenafil group compared with the non-sildenafil group. No significant differences were observed in systemic arterial pressure values between both groups. Nitric oxide levels were significantly higher for all periods in the sildenafil group. No differences were observed in histological studies. Conclusion. Our experimental work suggested a positive effect of sildenafil on the immediate posttransplant outcome of warm-ischemic kidneys without systemic secondary effects.