Assessing the impact of ischaemia time during partial nephrectomy.

CONTEXT

The impact of applying renal ischaemia during nephron-sparing surgery to avoid renal damage in the treated kidney has gained importance in different surgical techniques.

OBJECTIVE

The main objective of the present study is to point out the limit of renal ischaemia times for warm and cold ischaemia approaches. Important results of research on renal ischaemia and different surgical techniques as well as results of clinical studies concerning renal function after renal ischaemia in partial nephrectomy are highlighted.

EVIDENCE ACQUISITION

A Medline literature research was performed, combining queries on the keywords nephron-sparing surgery, partial nephrectomy, and ischemia. Links to related articles and cross-reading of citations in related articles were surveyed, as were reviews, letters to editors, and information collected from urologic textbooks. The references formed the basis of this review article, with selection and deletion based on the relevance and importance of the content. In a final step, interactive peer review by the expert panel of coauthors completed the review.

EVIDENCE SYNTHESIS

Renal ischaemia research showed an increasing renal damage proportional to ischemic time. Current clinical data support safe ischaemia times, within 20 min of warm ischaemia and up to 2 h of cold ischaemia, to minimise renal ischemic damage. To date, no ischaemia dose-response curve or algorithm is available to predict the risk of acute kidney injury and chronic kidney disease in patients undergoing intraoperative ischaemia. In general, there seems to be a higher risk for comorbidity caused by renal damage in patients suffering from kidney tumour.

CONCLUSIONS

If ischaemia is required, the tumour should be removed within 20 min of warm ischaemia, regardless of surgical approach. Efforts should be made to start immediately with cold ischaemia, if the feasibility within this span of time seems to be jeopardised. Thus, cold ischaemia times up to 2 h can be tolerated by the kidney, depending on the individual method. Nevertheless, cold ischaemia with ice slush should be kept as short as possible--at best within 35 min. In ischemic nephron-sparing surgery, one of the surgeon's main aims should be to avoid loss of renal function. Only after optimal preoperative appraisal and planning can the best postoperative outcomes for renal function be achieved.