Validity of estimated glomerular filtration rates for assessment of renal function after renal artery stenting in patients with atherosclerotic renal artery stenosis.

Objectives: The purpose of this study was to evaluate the validity of estimates of glomerular filtration rate (eGFR) for assessing serial changes in renal function after renal artery stenting.

Background: eGFR are unreliable for assessing serial renal function in patients with atherosclerotic renal artery stenosis (RAS). eGFR have not been validated for assessment of serial renal function after renal artery stenting.

Methods: Serum creatinine (SCr) and (125)I-iothalamate GFR (iGFR) were measured in RAS patients before and after renal artery stenting. eGFR were calculated from Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), and Cockcroft-Gault (CG) formulas. Using iGFR as the reference standard, the sensitivity, specificity, and area under the receiver-operating characteristic curve (AUC) were determined for MDRD, CKD-EPI, and CG for assessing changes in GFR before and after intervention.

Results: Between 1998 and 2007, 84 patients underwent iGFR and eGFR before and after renal artery stenting. All eGFR demonstrated poor sensitivity and reliability for detecting ≥20% changes in iGFR, and poor agreement in the magnitude and direction of change in iGFR, before and after renal stenting.

Conclusions: In RAS patients, eGFR demonstrate poor sensitivity and reliability for detecting meaningful changes in iGFR after renal artery stenting. eGFR should be abandoned as primary endpoints in major clinical trials assessing the impact of renal revascularization on renal function.