Acute Kidney Injury after Partial Nephrectomy of Solitary Kidneys: Impact on Long-Term Stability of Renal Function.

Abstract

Acute kidney injury often leads to chronic kidney disease in the general population. The long-term functional impact of acute kidney injury observed after partial nephrectomy has not been adequately studied. From 2004 to 2014 necessary studies for analysis were available for 90 solitary kidneys managed by partial nephrectomy. Functional data at 4 time points included preoperative serum creatinine, peak postoperative serum creatinine, new baseline serum creatinine 3 to 12 months postoperatively and long-term followup serum creatinine more than 12 months postoperatively. Adjusted acute kidney injury was defined by the ratio, observed peak postoperative serum creatinine/projected postoperative serum creatinine adjusted for parenchymal mass loss to reveal the true effect of ischemia. The long-term change in renal function (the long-term functional change ratio) was defined as the most recent glomerular filtration rate/the new baseline glomerular filtration rate. The relationship between the grade of the adjusted acute kidney injury and the long-term functional change was assessed by Spearman correlation analysis and multivariable regression. Median patient age was 64 years and median followup was 45 months. Median parenchymal mass preservation was 80%. Adjusted acute kidney injury occurred in 42% of patients, including grade 1 injury in 20 (22%) and grade 2/3 in 18 (20%). On univariable analysis the degree of the adjusted acute kidney injury did not correlate with the long-term glomerular filtration rate change (p = 0.55). On multivariable analysis adjusted acute kidney injury was not associated with a long-term functional change (p >0.05) while diabetes and warm ischemia were modestly associated with a long-term functional decline (each p <0.05). Acute kidney injury after partial nephrectomy was not a significant or independent predictor of long-term functional decline in our institutional cohort. A prospective study with larger sample sizes and longer followup is required to evaluate factors associated with long-term nephron stability.