Evaluation of digital venous angiography for the diagnosis of renovascular hypertension.

Thirty-two patients being evaluated for hypertension by angiography were also studied by digital video subtraction angiography (DVSA). Twenty-three of the 76 renal arteries were found by conventional angiography to have significant lesions. Two experienced angiographers evaluated the DVSA studies without knowledge of the angiographic results. The accuracy of DVSA for evaluation of renal arteries was 87% for Observer I and 80% for Observer II. Sensitivities were 87% and 83% and specificities 87% and 79% for the two observers. Of the 13 patients with significant lesions, Observer I identified at lest one lesion in all 13 while Observer II identified a lesion in 12 of the 13. The high false-positive rate (26% for Observer I and 37% for Observer II) was thought to be caused by subtraction artifacts, quantum noise, relatively low spatial resolution, and the Mach effect.