Renal Artery Pressure Gradients in Patients With Angiographic Evidence of Atherosclerotic Renal Artery Stenosis

From October 1979 to August 1991, 231 patients underwent renal artery balloon angioplasty at The Ohio State University Hospitals. Atherosclerotic renal vascular disease was present in 171 of these patients. From this cohort, 138 patients undergoing their first angioplasty had renal artery pressure gradients performed before and after renal artery angioplasty. The demographics of this group included age 66.9 ± 10 years (±SD), male 51%, white 94%, black 6%, diabetes mellitus 28%, systolic blood pressure 157 ± 26 mm Hg, diastolic blood pressure 86 ± 13 mm Hg, standard daily doses of antihypertensive medications 4.2 ± 3, and serum creatinine 2.6 ± 2.3 mg/ dL. Plasma renin activity was measured in 25 patients and was shown to be elevated in 16. The renal artery stenoses were main renal artery 75%, orificial 22%, distal renal artery 1.4%, and combinations of the above 2.2%. Solitary kidneys were present in six patients (4.3%). Bilateral renal artery stenosis was present in 45% of patients and bilateral angioplasties were performed in one third of these patients. The preangioplasty systolic blood pressure gradient was 109 ± 50 mm Hg (range, 20 to 230 mm Hg) and the postangioplasty renal artery pressure gradient was 12 ± 16 mm Hg (range, 0 to 78 mm Hg) (P < 0.001). There were no complications related to measurement of the pressure gradients. The magnitude of the renal artery pressure gradients did not correlate with blood pressure level, number of antihypertensive medications, or serum creatinine level. In conclusion, measurement of renal artery pressure gradients is safe and useful in defining hemodynamic significance and immediate response to angioplasty of stenotic renal artery lesions. Whether the reduction in renal artery pressure gradients achieved by the angioplasty is a predictor of the long-term success of the procedure is the subject of an ongoing study.