Abstract 15607: Renal Artery Stenting Causes Acute Proximal Tubule Dysfunction
Background: The effects of renal artery stenting on renal function are not well understood. N-acetyl-β-D-glucosaminidase (NAG) is released from injured proximal tubule cells, and β-2-Microglobulin (B2M) reabsorption is dependent on proximal tubule function. We investigated if urine NAG and B2M are elevated at baseline in patients with renal artery stenosis, and if levels increase following stenting.
Methods: Urine samples were collected from 30 healthy adults (Normals), 30 patients with atherosclerosis and risk factors for renal disease but not renal artery stenosis (Atherosclerosis), and 72 patients with stenosis undergoing renal artery stenting (RAS). In the RAS group, additional samples were obtained 24 hours and one month post procedure. Samples were measured by ELISA and corrected for urine creatinine. Statistical analysis was performed on the natural log transformed data of matched pairs, reported as mean±SD.
Results: NAG was higher in RAS than in Atherosclerosis (1.4±1.5 U/g vs. 0.69±0.74 U/g; p=0.0066), and higher in Atherosclerosis than in Normals (0.38±0.37 U/g; p=0.0017 compared to Atherosclerosis, p=0.0001 compared to RAS). Likewise, B2M was higher in RAS than in Atherosclerosis (−3.2±2.2 μg/L vs. −4.2±0.86 μg/L; p=0.031), and higher in Atherosclerosis than in Normals (−5.6±1.30 μg/L; p=0.0019 compared to Atherosclerosis, p<0.0001 compared to RAS). A substantial number of RAS patients had proximal tubule dysfunction at baseline (54% had elevated NAG, 26% had elevated B2M). Tubular function worsened at 24 hours (NAG 1.4±1.5 U/g vs. 1.8±1.3 U/g; p=0.028, B2M −3.2±2.3 μg/L vs. −2.4±1.9 μg/L; p=0.019), but returned to baseline by one month after (Figure, graphed as mean±SE).
Conclusions: Proximal tubule injury is commonplace in patients with renal artery stenosis and is not fully attributable to risk factors such as atherosclerosis. Proximal tubule function appears to worsen in the 24 hours following stenting, but returns to baseline by one month.
- © 2010 by American Heart Association, Inc.