Determination of Renal Arterial Stenosis Severity: Comparison of Pressure Gradient and Vessel Diameter

PURPOSE: To determine the hemodynamic significance of arteriographically detected renal arterial stenosis by obtaining pressure gradients with a miniaturized pressure guide wire. MATERIALS AND METHODS: Forty-six renal arterial stenoses in 38 patients were assessed in terms of severity and then subjected to gradient determination before and after angioplasty. The patients (mean age, 63 years) had a mean serum creatinine value of 1.3 mg/dL +/- 0.4 (114.9 micromol/L +/- 35.4 [SD]) and required on average three medications for blood pressure control. The mean degree of stenosis diameter was 51% +/- 17 (range, 12%-85%). RESULTS: The systolic and mean arterial pressure gradients with and those without vasodilatation were highly correlated with stenosis severity, systolic blood pressure, and serum creatinine as a curvilinear fit (r = 0.9, P <.01). At 50% stenosis severity, the mean pressure gradient was 22 mm Hg. CONCLUSION: Patients with a pressure gradient greater than 20 mm Hg should be good candidates for renal arterial dilatation, and use of the pressure guide wire will facilitate interventional decisions.