The effect of warm ischemia duration on renal function early after laparoscopic partial nephrectomy

Objective To assess the effect of variable durations of warm ischemia on renal function early after laparoscopic partial nephrectomy (LPN) and make the definite safety duration of renal warm ischemia. Methods The clinical data of 76 patients treated with LPN from October 2012 to June 2014 were retrospectively analyzed. The patients were divided into 3 groups based on warm ischemic time, namely group A (28 cases) with warm ischemia time less than 20 min, group B (34 cases) with warm ischemia time more than 20 min and less than 30 min, group C (14 cases) with warm ischemia time more than 30 min.LPN was performed with renal artery clamping alone in all the patients.Preoperative and postoperative renal scintigraphic scan was performed to access glomerular filtration rate (GFR) in all patients.The GFR values were compared among before, 1 week, 1 month and 3 months after operation.The factors predicting the early renal injury were assessed by multivariate regression analysis. Results The renal GFR of the kidney underwent LPN decreased 19.43(17.70, 22.06) ml/min at 1 week, 17.04(13.94, 20.70) ml/min at 1 month, 13.82(10.72, 18.73) ml/min at 3 months after the surgery in group C, respectively.In group A, the renal GFR of the operated-side decreased 12.07(10.91, 13.42) ml/min, 10.04(9.16, 11.75) ml/min, 8.44(7.07, 9.72) ml/min, respectively.In group B, the renal GFR of the operated-side decreased 13.64(12.48, 16.72) ml/min, 10.29(9.17, 14.27)ml/min, 9.63(7.85, 12.59) ml/min, respectively.The GFR decreased greater in group C than that in group A and B(P 0.05). The multivariate regression analysis revealed that warm ischemia duration was the independent risk factor of the early renal injury. Conclusions Warm ischemia duration is the major factor regarding the early renal recovery after LPN.Warm ischemia time more than 30 min may not only greatly affect the renal function but also the renal function recovery rate. Key words: Laparoscopes; Nephrectomy; Warm ischemia; Renal function