The current interest in renovascular hypertension had stimulated a great deal of investigation concerning its diagnostic criteria. From all available reports1-7 it is apparent that the methods for selection of patients for surgery do not always yield uniform results. Of the reasons responsible for the discrepancies obtained with the various tests, the most significant seems to be the lack of precise correlation of the findings with the degree of arterial lesions. Indeed the exact range of arterial narrowing leading to hemodynamic alterations associated with renal hypertension has still not been clearly defined. In view of the increasing clinical importance of renal-artery lesions as an etiologic factor in hypertension, such a study appeared of great interest.
In a previous investigation8 correlation between manometric and arteriographic findings with the degree of stenosis disclosed: (1) that reduction of the arterial lumen of about 60% of the diameter or 84% of the