Hypertension and the Kidney COMPARISON OF DUPLEX ULTRASOUND WITH ARTERIOGRAPHY

Hypokalemia FIGURE 3-16 Comparison of duplex ultrasound with arteriography. A total of 102 consecutive patients with both duplex ultrasound scanning of the renal arteries and renal arteriography were prospectively studied. All patients in this study had difficult-to-control hypertension, unexplained azotemia, or associated peripheral vascular disease, giving them a high pretest likelihood of renovascular hypertension. Sixty-two of 63 arteries that showed less than 60% stenosis by formal arteriography, were identified by duplex ultrasound scanning. Twenty-two of 23 arteries with total occlusion on arteriography were correctly identified by duplex ultrasound. Thirty-one of 32 arteries with 60% to 79% stenosis using arteriography were identified as having 60% to 99% stenosis on duplex ultrasound and 67 of 69 arteries with 80% to 99% stenosis on arteriography were detected to have 60% to 99% stenosis on ultrasound. A current limitation of duplex ultrasound is the inability to consistently distinguish between more than and less than 80% stenosis (considered to be the magnitude of stenosis required for hemodynamic significance of the lesion). Nevertheless, duplex ultrasound is currently highly sensitive and specific in patients with a high likelihood of renovascular disease in detecting patients with more or less than 60% renal artery stenosis. Accessory renal arteries are difficult to identify by ultrasound and remain a limitation of this test. (Adapted from Olin and coworkers [5]; with permission.)