Non-invasive ultrasound assessment of renal artery stenosis by means of the Gosling pulsatility index.

OBJECTIVE

To gauge the effectiveness of a new Doppler test for renal artery stenosis (RAS), based on the pulsatility index of the blood flow velocity spectrum within several interlobar arteries of both kidneys.

METHODS

Twenty normotensive volunteers and 49 hypertensive patients were investigated with ultrasound. Patients with angiographic signs of RAS underwent bilateral renal vein catheterization for renin measurement. Significant RAS was assumed if lateralization of renal vein renin to the stenotic side was proven.

RESULTS

The pulsatility index was higher in the hypertensives without RAS than in normal volunteers. Side differences between both kidneys were within methodological variations with the exception of one case, in whom side difference was > 0.12. The pulsatility index was lower in kidneys with significant RAS than in kidneys without RAS. In most patients with significant unilateral RAS the side difference was < 0.12. In the other patients with a low pulsatility index and a side difference < 0.12 RAS was found to be bilateral upon angiography. Doppler signals were absent in all kidneys with renal occlusion.

CONCLUSIONS

A side difference of > or = 0.12 predicts unilateral RAS, whereas the absence of parenchymal Doppler signals indicate occlusive RAS. A low pulsatility index combined with normal side difference may, in hypertensive patients, indicate bilateral RAS. Renovascular hypertension was correctly diagnosed in 84% of the patients and the presence of RAS in 94%.