2. UroToday Home
  3. Conference Highlights
  4. WCE 2018

WCE 2018: On-Clamp Versus Off-Clamp Partial Nephrectomy: Propensity Score Matched Comparison of Long Term Functional Outcomes

Paris, France (UroToday.com) For partial nephrectomy, the decision to clamp the renal artery and vein during partial nephrectomy (PN) has largely been debated among practicing urologists. Though clamping the renal artery during PN will lead to a reduction in bleeding intraoperatively, some urologists would argue that kidney function is reduced postoperatively. Dr. Giuseppe Simone and his team from the “Regina Elena" National Cancer Institute in Rome set out to settle this debate with their study. The researchers attempted to conduct this by comparing renal function outcomes after off-clamp (Off-C) or on-clamp (On-C) PN in patients with cT1-2/N0 M0 renal tumors and baseline estimated glomerular filtration rate (eGFR) >60 mL/min.

In order to determine the differences between Off-C or On-C modalities, the researchers conducted a prospective renal cancer database at two high volume centers, screening for patients with the aforementioned tumor and renal characteristics. Following the completion of the data collection process, 1,073 patients were recruited which consisted of 588 On-C PN patients and 485 Off-C PN patients. Univariate and multivariate analyses, along with 1:3 propensity score-matched analysis and Joinpoint regression analysis, were then conducted by the researchers in order to properly analyze the data for trends regarding postoperative renal function.

In regard to clinical and pathological covariates, the On-C cohort was significantly younger, less likely to smoke, lower incidence of diabetes and hypertension, lower ASA scores, higher eGFR, and smaller tumor sizes. However, after 1:3 propensity score-matched analysis was completed, the cohorts of On-C (n=157) and Off-C (n=471) PN, there were no significant differences between the aforementioned clinical and pathological covariates. Following Joinpoint regression analysis, it was shown that the Off-C cohort had a significantly higher probability of maintaining an unmodified eGFR after surgery and a significantly lower probability of seeing a reduction of eGFR >25% in the first 8 years of follow-up. A Kaplan-Meier curve given by the researchers showed a visual representation of the risk of eGFR reduction during their patients’ follow up period   (Figure 1). The possibility of developing CKD stage ≥3b was significantly higher on the On-C cohort.

UroToday WCE2018 Kaplan Meier curve showing the risk of estimated glomerular filtration rate
Figure 1: Kaplan-Meier curve showing the risk of estimated glomerular filtration rate decreasing to less than 45 mL/min between the On Clamp versus Off Clamp cohorts over ten years.  

In his conclusory statements, Dr. Simone attempted to settle the debate with his study by asserting that the Off Clamp partial nephrectomy is associated with a significantly higher probability of maintaining 100% eGFR after surgery compared to On Clamp patients with cT1-2/N0 M0 renal tumors. He additionally stated that the patients with On-C PN were 7.3 times more likely to developed severe CKD during follow up.


Presented by: Giuseppe Simone, MD "Regina Elena" National Cancer Institute, Dept. of Urology, Rome, Italy
Co-Authors: Giuseppe Simone1, Umberto Capitanio2, Alessandro Larcher2, Gabriele Tuderti1, Mariaconsiglia Ferriero1, Leonardo Misuraca1, Manuela Costantini1, Francesco Minisola1, Salvatore Guaglianone1, Fabio Muttin2, Alessandro Nini2, Francesco Trevisani2, Francesco Montorsi2, Roberto Bertini2, Michele Gallucci1

Author Affiliation: 1."Regina Elena" National Cancer Institute, Dept. of Urology, Rome, Italy; 2. Hospital San Raffaele, University Vita Salute, Department of Urology, Milan, Italy

Written by: Zachary Valley Twitter: @ZacharyAValley, Department of Urology, University of California-Irvine, medical writer for UroToday.com at the 36th World Congress of Endourology (WCE) and SWL - September 20-23, 2018 Paris, France