Warm ischemia less than 30 minutes is not necessarily safe during partial nephrectomy: Every minute matters
ABSTRACT At the 11th Annual Meeting of the Society of Urologic Oncology (SUO), an expert panel discussed the importance of warm ischemia time on renal function during partial nephrectomy. The position of this manuscript is that every minute of warm ischemia time has a deleterious effect on renal function outcomes following partial nephrectomy.
The presentation was derived from a review of the published urologic, nephrology, and transplant literature related to warm ischemia time and renal function outcomes.
There exist numerous clinical models to study the effects of warm ischemia on renal function. These include the bilateral kidney, unilateral partial nephrectomy, solitary kidney partial nephrectomy, and transplant kidney model. Each of these models provides evidence for minimizing warm ischemia time to prevent acute renal failure, chronic kidney disease, and end stage renal failure. In the best available model, solitary kidney partial nephrectomy, each minute of warm ischemia was found to be associated with a 6% increased risk of acute renal failure, 7% increased risk of acute-onset end stage renal disease (ESRD), and 4% increased risk of new-onset ESRD while controlling for preoperative renal function, tumor size, and surgical approach.
There is ample evidence, consistent across multiple human kidney models, supporting the potentially deleterious renal effects of warm ischemia during partial nephrectomy. There does not appear to be a known safe threshold of warm ischemia since each minute sequentially contributes to the risk of developing acute kidney injury and renal function decline. Ultimate renal function following PN is dependent on the "3 Qs": quality (renal function prior to surgery), quantity (renal parenchyma preserved during surgery), and quickness (ischemia time).
[Show abstract] [Hide abstract]
ABSTRACT: Ischemia time during partial nephrectomy is strongly associated with acute and chronic renal injury. ATP depletion during warm ischemia inhibits ATP-dependent processes, resulting in cell swelling, cytoskeletal breakdown and cell death. The duration of ischemia tolerated by the kidney depends on the amount of ATP that can be produced with residual substrates and oxygen in the tissue to sustain cell function. We previously reported that the rat can tolerate 30 min ischemia quite well but 45 min ischemia results in acute kidney injury and progressive interstitial fibrosis. Here we report that pretreatment with SS-20 thirty min prior to warm ischemia in the rat increased ischemia tolerance from 30 min to 45 min. Histological examination of kidney tissues revealed that SS-20 reduced cytoskeletal breakdown and cell swelling after 45 min ischemia. Electron microscopy showed that SS-20 reduced mitochondrial matrix swelling and preserved cristae membranes, suggesting that SS-20 enhanced mitochondrial ATP synthesis under ischemic conditions. Studies with isolated kidney mitochondria showed dramatic reduction in state 3 respiration and respiratory control ratio after 45 min ischemia, and this was significantly improved by SS-20 treatment. These results suggest that SS-20 increases efficiency of the electron transport chain and improves coupling of oxidative phosphorylation. SS-20 treatment after ischemia also significantly reduced interstitial fibrosis. These new findings reveal that enhancing mitochondrial bioenergetics may be an important target for improving ischemia tolerance, and SS-20 may serve well for minimizing acute kidney injury and chronic kidney disease following surgical procedures such as partial nephrectomy and transplantation.American journal of physiology. Renal physiology 10/2014; 308(1):ajprenal.00366.2014. DOI:10.1152/ajprenal.00366.2014 · 3.30 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: Nephron-sparing surgery has become the standard treatment for T1 renal tumors. However, relevant data on the Taiwanese population are lacking, and most of the current literature uses global instead of split renal function (SRF) for postoperative renal function follow-up. We evaluated the postoperative renal function after minimally invasive partial nephrectomy in Taiwanese patients.Methods We retrospectively reviewed our database from April 2004 to July 2012 and enrolled patients who received laparoscopic partial nephrectomy (LPN) or robot-assisted partial nephrectomy (RPN). The estimated glomerular filtration rate (eGFR) and SRF were calculated as representatives of renal function. The preoperative and 6- and 12-month postoperative renal functions were assessed. Freidman test was used to evaluate pre- and postoperative renal function changes; Wilcoxon test was used for comparing the renal function of each period.ResultsThe 6- and 12-month postoperative SRF values were decreased compared with the preoperative values. Multivariate analysis revealed that older age was related to a lower postoperative eGFR, and a longer warm ischemia time was related to a decreased postoperative SRF. Patients with a warm ischemia time of >30 minutes were correlated with a larger mean tumor size, higher “preoperative aspects and dimensions used for an anatomical” score, greater amount of blood loss during the operation, longer postoperative hospital stay, and lower postoperative SRF compared with patients with a warm ischemia time of <30 minutes. Patients in the RPN group had shorter warm ischemia time and higher 6-month postoperative SRF compared with patients in the LPN group.ConclusionSRF is more sensitive for postoperative follow-up than eGFR. Longer warm ischemia time is associated with poorer postoperative renal function. RPN is a safe and feasible alternative to LPN.Journal of the Chinese Medical Association 10/2014; 78(1). DOI:10.1016/j.jcma.2014.09.002 · 0.89 Impact Factor
European Urology 01/2015; 29. DOI:10.1016/j.eururo.2014.09.043 · 12.48 Impact Factor