There is a paradox in hypertension: whereas the pathophysiological mechanisms of the disease have been related principally to a constriction of small arteries, most of the complications refer to damage of the large arteries, particularly at the site of the brain, the kidney and the heart. In the past, large arteries were poorly investigated in hypertension mainly in terms of change in blood flow.

MICHEL E. SAFAR and MICHAEL F. O'ROURKE One of the principal problems of hypertension is the precise definition of blood pressure as a cardiovascular risk factor. Clinicians indicate peak systolic pressure and end diastolic pressure in the brachial artery as the principal criteria for blood pressure measurement. Consequently, these values are as indicators for clinical management and therapeutic adjustment. This used methodology, based on indirect blood pressure measurements at the site of the brachial artery relates only to the highest and lowest pressure in that vessel, and does not give...