Login to Access Video or Poster Abstract: MP49-10
Sources of Funding: none

Introduction

Partial nephrectomy (PN) is the standard treatment for localized renal cancer due to better preservation of renal function. Previous studies suggested that parenchymal mass preservation is a key determinant of functional outcomes, while ischemia plays a secondary role. Analyses that focus specifically on recovery of the kidney exposed to ischemia appear to be most informative, yet have only included limited numbers of patients. Our objective is to provide a more refined evaluation of the impact of ischemia type and duration using more robust numbers of patients analyzed in this manner.

Methods

A total of 401 patients with PN at our center (2007-2015) had necessary data for analysis, including serum creatinine-based estimated glomerular filtration rate (GFR) and contrast-enhanced cross-sectional imaging studies <2 months prior and 3-12 months after PN. Patients with 2 kidneys were also required to have split renal function from nuclear renal scans within the same timeframes. Recovery from ischemia was defined as percent function preserved in the ipsilateral kidney normalized by percent parenchymal mass preserved. Pearson correlation evaluated the relationships between functional recovery and parenchymal mass preserved or ischemia time. Multivariable linear regression assessed predictors for recovery.

Results

Median tumor size was 3.5 cm and median R.E.N.A.L. was 8. Cold/warm ischemia were utilized in 151/250 patients, and median ischemia times were 27/21 minutes, respectively. Parenchymal mass preserved correlated strongly with function preserved (r=0.63, p<0.001). Median recovery from ischemia, which normalizes for parenchymal mass preservation, was significantly higher for hypothermia than warm ischemia (99% vs. 92%, p<0.001) and remained consistently strong even with longer duration of cold ischemia. Multivariable analysis demonstrated that ischemia type and duration associated significantly with recovery from ischemia (p<0.05). However, each additional 10 minutes of warm ischemia associated with only 2.5% decline in recovery from ischemia.

Conclusions

Parenchymal mass preservation is the primary factor affecting functional outcomes after clamped PN. Beyond this, functional recovery is most reliable with hypothermia. Longer intervals of warm ischemia associate with reduced recovery; however, incremental changes are modest and of debatable clinical significance, particularly in patients with a normal contralateral kidney.

Funding

none