Impact of ischaemia time on renal function after partial nephrectomy: a systematic review

Objective To assess the impact of ischaemia on renal function after partial nephrectomy (PN). Materials and methods A literature review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. In January 2015, the Medline and Embase databases were systematically searched using the protocol ('warm ischemia'[mesh] OR 'warm ischemia'[ti]) AND ('nephrectomy'[mesh] OR 'partial nephrectomy'[ti]). An updated search was performed in December 2015. Only studies based on a solitary kidney model or on a two-kidney model but with assessment of split renal function were included in this review. Results Of the 1119 studies identified, 969 abstracts were screened after duplicates were removed: 29 articles were finally included in this review, including nine studies that focused on patients with a solitary kidney. None of the nine studies adjusting for the amount of preserved parenchyma found a negative impact of warm ischaemia time on postoperative renal function, unless this was extended beyond a 25-min threshold. The quality and the quantity of preserved parenchyma appeared to be the main contributors to postoperative renal function. Conclusion Currently, no evidence supports that limited ischaemia time (i.e. <= 25 min) has a higher risk of reducing renal function after PN compared to a 'zero ischaemia' technique. Several recent studies have suggested that prolonged warm ischaemia (>25-30 min) could cause an irreversible ischaemic insult to the surgically treated kidney.