Abstract: PD66-04
Sources of Funding: None

Introduction

Warm ischemia time (WIT) is one of the primary determinants of post partial nephrectomy (PN) renal function, with conflicting data about the importance of every minute or a duration threshold beyond which renal damage occurs. We aimed to explore whether variation within short warm ischemia time (<25 minutes) affects renal functional outcome.

Methods

A multi-institutional database of robotic partial nephrectomy (RPN) patients comprising five high volume surgeons at five U.S. institutions was used to identify 703 patients with two kidneys undergoing main renal artery clamping RPN. Multivariable regression analysis assessing the impact of WIT on acute kidney injury (AKI) and progression of chronic kidney disease (CKD) stage, adjusting for underlying factors such as comorbidities, tumor size, RENAL Nephrometry Score (RNS), surgeon RPN number, and baseline eGFR was performed. WIT was treated as a continuous variable and as a categorical variable using specified cut points derived from the interquartile range and median WIT, and WIT of >25 min.

Results

WIT continuous (OR=1.08; 95% CI = 1.04, 1.12, p<.001) and WIT > 25 vs. WIT 20 – 25 minutes (OR=5.08, 95% CI = 1.94 – 14.36, p=.001) were associated with an increased likelihood of AKI at discharge in multivariable analysis (Table I., Figure I.), but not an increased likelihood of CKD at median 6.8 or 11.5 months follow up. No other threshold below 25 minutes was significantly more likely to increase the likelihood of AKI (p>.05). Higher baseline eGFR (HR=1.01, p=.002), larger tumors (HR=1.15, p=.018), higher RNS (HR=1.18, p=.029), history of abdominal surgery (HR=1.53, p=.05), as well as AKI at discharge (HR=1.94; p=.002) were associated with an increased risk of CKD stage progression.

Conclusions

Variability of WIT within 25 minutes does not appear to increase the risk of AKI or progression of CKD. Extended WIT beyond 25 minutes is highly correlated with an increased likelihood of AKI, supporting previously reported literature. Techniques to reduce or eliminate warm ischemia may not be necessary when WIT is expected below 25 minutes.

Funding

None