Renal artery stenosis as a cause of secondary treatable hypertension: Colour and duplex doppler evaluation, diagnostic criteria and efficacy

ABSTRACT

Renal artery stenosis is the cause of hypertension in a small percentage of all patients with hypertension, but is the only anatomic cause that can be treated by surgery or angioplasty. Recent studies indicated that Doppler characteristics aided with color Doppler imaging is an adequate screening method for such cases. This study aimed to evaluate the use and feasibility of color and duplex Doppler scanning and its criteria for detection and evaluation of renal artery stenosis as a cause of h hypertension. The renal artery was studied by this method all over its whole course in 32 patients, selected clinically with a hypertension suggested to be of renovascular origin. Another ten normal cases were studied as a representative of normal findings used for comparison. Transfemoral aortography [aortic flush angiography] was used for confirmation of the ultrasonography [US] findings and assessment of the degree of renal artery stenosis. The findings defined the use of three parameters concomitantly to give an accurate identification of the renal artery stenosis. Also, it showed that these parameters together [peak velocity, pulsatility index and resistivity index] had a high sensitivity, specificity, positive predictive value, negative predictive value and an overall accuracy of 100%, 86.96%, 84.21%, 95.2% and 92.3%, respectively, for renal artery disease detection. It was concluded that duplex aided with color Doppler US study of renal arteries of hypertensive patients can reliably detect renal artery stenosis, that can be therefore a valuable tool in selection of hypertensive patients for angiography and for either angioplasty or surgical management