Digital video subtraction angiography: screening technique for renovascular hypertension

Significant deterrents to the detection of renovascular hypertension are the unreliability of current screening methods and the widespread belief that the incidence of renal artery stenosis is too low to justify the expense and morbidity of routine angiography. We have developed a new imaging method, digital video subtraction angiography, suitable for screening outpatients for renal artery lesions. It involves injecting a 45 cc bolus of contrast medium through a venous catheter. Instead of exposing x-ray film, images are recorded directly on an image intensifier, digitized, and stored in a computer that electronically subtracts, reconstructs, enhances, and magnifies the images on a video screen. Renal parenchymal vessels less than 1 mm in diameter can be seen. So far, 45 studies have been performed in 39 hypertensive patients. Images of diagnostic quality were obtained in all except one. Renal artery stenosis was revealed in 15 patients, renal artery occlusion in two, diffuse intrarenal arterial narrowing in two, atrophic kidney with small renal arteries in two, and normal renal vessels in 23. Digital video subtraction angiography is an inexpensive, cost-effective, safe, and accurate method for renovascular hypertension screening and for evaluating patients after surgical correction of renal artery stenosis.