Renal stenting for the incidentally discovered renal artery stenosis: Is there any outcome benefit?

Laurel Imhoff and Niren Angle, M.D.
UCSD Section of Vascular & Endovascular Surgery, San Diego, CA

Objective: Treatment options for atherosclerotic renal artery stenosis (RAS) include medical management and/or percutaneous transluminal angioplasty with stenting (PTRAS) or surgical revascularization. The appropriate treatment is controversial even when a clear diagnosis of RAS exists. Often during coronary or lower extremity angiography, an incidental finding of renal stenosis is made. The goal of this study was to identify a set of patients undergoing renal angiography between the years 2000 to 2004 and determine how patients diagnosed with high grade RAS are managed and identify if PTRAS in this population is associated with blood pressure and/or renal function improvement.
Methods: A retrospective cohort study of patients who undergoing renal artery angiography during 2000-2004 was conducted. Demographic and clinical characteristics were collected from patient charts. Review of catheterization operative reports identified patients diagnosed with high grade RAS as well as those treated with PTRAS. Blood pressure measurements, anti-hypertensive medications and serum creatinine levels were followed for 3 months and 1 year.
Results:
One hundred and twenty four patients underwent renal artery angiography for suspected athlerosclerotic RAS during 2000-2004. Fifty two patients (41%) had a pre-existing diagnosis of RAS and 78 patients (63%) were diagnosed with high grade RAS (either unilateral or bilateral) at the time of angiography. Of those patients, 58 (74%) received an intervention. Patients treated with renal stenting for unilateral RAS as a whole had a significant reduction in mean SBP (from 153 to 136 mmHg; p=0.01) and MAP (from 103 to 95 mmHg; p=0.04); however, this decrease in SBP only occurred concurrent with an increase in BP medications. In those patients treated with PTRAS that had no change or a decrease in BP medications, no significant decrease in SBP was found. No significant improvement in DBP or serum creatinine was demonstrated. All patients diagnosed with RAS, treated with PTRAS, and concurrently managed with an increase in the number of anti-hypertensive medication demonstrated blood pressure improvement (mean SBP from 158 to 128 mmHg, p<0.01; Mean DBP from 80 to 64 mmHg, p=0.04; MAP from 106 to 85 mm Hg, p=0.016). This improvement did not occur in the patient groups with the same or a reduced anti-hypertensive medication regimen.
Conclusions: In the modern era, at a university center, renal artery stenting is done often for an incidentally discovered renal artery stenosis. Of patients treated with PTRAS for high grade renal artery stenosis, the only improvement in blood pressure was found in those that concurrently had an increase in medical therapy. This suggests that patients with an incidentally discovered renal artery stenosis do not benefit in terms of improvement in blood pressure or excretory renal insufficiency from renal artery stenting.