Abstract: PD66-05
Sources of Funding: None

Introduction

Mannitol has been shown in animal models to have a renoprotective effect during warm ischemia, but these potential benefits have yet to be demonstrated in clinical studies. Despite this, mannitol is still used in about 75% of partial nephrectomies (PN). Using the largest PN series to date, we sought to identify any short-term or long-term preservation in renal function through the use of intraoperative mannitol, with a particular focus on high risk groups.

Methods

We retrospectively reviewed 1,415 robotic and open PN patients over a period of 6 years. Doubly robust inverse probability of treatment weighting (DR-IPTW) was applied to attempt to equilibrate treatment groups with regards to clinicodemographic characteristics. Acute kidney injury (AKI) was defined as a change in preop GFR >25% within 72 hours of surgery, or stage 1 of the RIFLE criteria. GFR preservation (GFR-P) was defined as 100*GFR at 3-12 months/Preop GFR. A propensity-weighted adjusted logistic regression was employed to determine the relationship between the treatment group, renal functional outcomes, and baseline covariates. Subgroup analyses were performed on patients with baseline CKD, prolonged ischemia time (>25 vs <25 min), cold and warm ischemia, and solitary kidneys.

Results

73.5% of patients received mannitol. After weighting, there were no statistical differences in baseline characteristics (p>0.05). In the cohort at large, 34.8% developed AKI and global GFR-P was 90.4% at a median 6 month follow-up. There were no differences in the outcomes of AKI (OR 1.14 [95% CI, 0.84-1.54]) and GFR-P (β = 1.34 [95% CI, -1.41-4.09]) between treatment groups. In subgroup analyses, there were no differences in the outcomes of AKI (OR 1.03 [95% CI, 0.51-2.10]) or GFR-P (β =1.28 [95% CI, -9.77-7.21]) in patients with preexisting CKD, prolonged ischemia time (AKI, OR 1.16 [95% CI, 0.64-2.11] ; GFR-P, β =1.76 [95% CI, -3.96-7.47]), cold ischemia (AKI, OR 1.02 [95% CI, 0.54-1.91] ; GFR-P, β =1.39 [95% CI, -4.62-7.40]), warm ischemia (AKI, OR 1.14 [95% CI, 0.77-1.69] ; GFR-P, β =1.16 [95% CI, -2.10-4.42]), and in solitary kidneys (AKI, OR 0.21 [95% CI, 0.24-1.20] ; GFR-P, β =13.2 [95% CI, -5.73-32.2]).

Conclusions

Mannitol use in PN failed to provide any short-term or long-term renoprotective benefit. This held true within subgroup analyses including patients with preexisting CKD, prolonged ischemia times, cold and warm ischemia groups and in solitary kidneys. Despite evidence from animal models, there does not appear to be a role for mannitol use clinically during PN.

Funding

None