Analysis of Atrophy After Clamped Partial Nephrectomy and Potential Impact of Ischemia

Abstract

Ischemia is a potential contributor to decline of function after partial nephrectomy (PN), although loss of parenchymal mass related to excision and reconstruction appears to be a more significant factor. However, loss of parenchymal mass could also be due to global effects of ischemia leading to parenchymal atrophy. In this study, we evaluated parenchymal volumes in regions away from the operated site to assess for atrophy. A total of 164 patients undergoing PN for whom detailed analysis of function and parenchymal mass within the operated kidney could be performed were assessed for opposite pole volume (OPV) before and 4-12 months after surgery. Tumor location was required to be ≥2 cm away from the opposite polar line to exclude local effects related to excision or reconstruction. OPV was estimated by software analysis, and the ratio of the estimates (OPV ratio = postoperative OPV to preoperative OPV) was used to assess for atrophy. Patient demographics and tumor characteristics were representative of conventional PN populations, and warm ischemia (n = 101; median, 21 minutes) and cold ischemia (n = 63; median, 26 minutes) were applied by surgeon discretion. OPVs before and after PN were 63.2 and 62.5 cm(3), respectively (P = .76). The median OPV ratio was 0.99 suggesting that significant atrophy did not occur. OPV ratio was 0.99 for warm ischemia cases and 0.99 for cold ischemia cases (P = .95). Limited warm ischemia or hypothermia was not associated with significant parenchymal atrophy after PN, which suggests that parenchymal volume loss in this setting is primarily due to excision or reconstruction.