Long‐term response to renal ischaemia in the human kidney after partial nephrectomy: results from a prospective clinical trial

Abstract

Objective To assess the 1-year renal functional changes in patients undergoing partial nephrectomy with intra-operative renal biopsies. Patients and Methods A total of 40 patients with a single renal mass deemed fit for a partial nephrectomy were recruited prospectively between January 2009 and October 2010. We performed renal biopsies of normal renal parenchyma and collected serum markers before, during and after surgically induced renal clamp ischaemia during the partial nephrectomy. We then followed patients clinically with interval serum creatinine and physical examination. Results Peri-operative data from 40 patients showed a transient increase in creatinine levels which did not correlate with ischaemia time. Renal ultrastructural changes were generally mild and included mitochondrial swelling, which resolved at the post-perfusion biopsy. A total of 37 patients had 1-year follow-up data. Creatinine at 1 year increased by 0.121 mg/dL, which represents a 12.99% decrease in renal function from baseline (preoperative creatinine 0.823 mg/dL, estimated glomerular filtration rate = 93.9 mL/min/1.73 m2). The only factors predicting creatinine change on multivariate analysis were patient age, race and ischaemia type, with cold ischaemia being associated with higher creatinine level. Importantly, the duration of ischaemia did not show any significant correlation with renal function change, either as a continuous variable (P = 0.452) or as a categorical variable (P = 0.792). Conclusions Our data suggest that limited ischaemia is generally well tolerated in the setting of partial nephrectomy and does not directly correspond to long-term renal functional decline. For surgeons performing partial nephrectomy, the kidney can be safely clamped to ensure optimum oncological outcomes.

Estimated glomerular filtration rate's time to nadir after robot‐assisted partial nephrectomy: Predictors and clinical significance on renal functional recovery

“…Kallingal et al . found that the kidney ischemic changes at the cellular level recovered after reperfusion with no correlation between renal functional at 1 year and WIT …”

“…Indeed, the impact of long WIT on postoperative renal function is maximized in the setting of a single renal unit . In the presence of two renal functioning units, its impact is present on the short term . Recovery of renal function after PN takes up to 1 year to stabilize, thus evaluating the risk factors affecting early postoperative renal function might be changed on the long‐term .…”

“…Similarly, 92% of laboratories in the USA still used the MDRD equation in reporting eGFR, with just 4% using the CKD‐EPI equation . In addition, we preferred to be adherent to most of the previous urology PN research, which used the MDRD equation …”

The sympathetic nervous system in acute kidney injury

“…[15][16][17] A clinical scenario that corresponds well to this form of experimental IR is clamping the renal artery prior to partial nephrectomy as performed in urological oncology to save functioning renal tissue. 18,19,21 However, in patients with a solitary kidney, the incidence of AKI positively correlated with ischaemia duration and was significantly higher than in patients with two functioning kidneys 20 suggesting that in patients with two kidneys, hyperfiltration of the contralateral non-ischaemic kidney masks IR-induced damage of the operated kidney. [18][19][20][21] This led to the suggestion that human kidneys may have a higher IR tolerance than kidneys from small laboratory animals used in experimental IR studies.…”

“…IR may be induced bilaterally or unilaterally with or without preceding unilateral nephrectomy. [18][19][20][21] This led to the suggestion that human kidneys may have a higher IR tolerance than kidneys from small laboratory animals used in experimental IR studies. [15][16][17] A clinical scenario that corresponds well to this form of experimental IR is clamping the renal artery prior to partial nephrectomy as performed in urological oncology to save functioning renal tissue.…”