Variations in renal size in the diagnosis of renovascular hypertension

Following the injection of water-soluble contrast medium and urea an increase in area of the renal shadow of less than 5 per cent was demonstrated on the affected side in 14 cases of hypertension due to renal artery stenosis (verified by operation and post-operative follow-up). On the contra-lateral side an increase of 7–20 per cent was observed in all cases. In 20 patients with hypertension and renal artery stenosis, but no surgical intervention, the same phenomenon was observed in six cases. In these patients other diagnostic criteria were also indicative of reno-vascular hypertension. It is concluded that the increase in renal size which is normally seen following the injection of water-soluble contrast medium and certain drugs is impaired in cases of significant renal artery stenosis. The underlying mechanism (also discussed in a previous paper) may in itself be responsible for the hypertension. If this be the case, measurements of variations in renal size during washout urograms would be very valuable in the diagnosis of renovascular hypertension.