ARTERIAL ALTERATIONS IN HYPERTENSION WITH A DISPROPORTIONATE INCREASEIN SYSTOLIC OVER DIASTOLIC BLOOD-PRESSURE

Background Although systolic and diastolic blood pressure and cardiova scular risk are directly related in epidemiologic studies, the results of large therapeutic trials in mild to moderate hypertension have ind icated that the prevention of cerebrovascular accidents was much more effective than that of coronary ischemic accidents. Actually, a signif icant decrease in coronary events was observed only in aged population s in which systolic (and not diastolic) blood pressure was chosen as c riterion of entry. Whether the choice of the mechanical factor (systol ic or diastolic blood pressure or both) used to define hypertension mi ght have created a bias in the studied populations remains an importan t question. Findings Above 50 years of age, most hypertensive populati ons are characterized by a disproportionate increase in systolic over diastolic blood pressure, so that the pulsatile component of blood pre ssure is strikingly augmented. This pattern is commonly observed in ol d people with essential hypertension, in hypertensive subjects with ad vanced renal failure undergoing hemodialysis and in atherosclerotic su bjects with hypertension, particularly those with atherosclerosis of t he lower limbs and cerebral vessels. In all these populations, the dis turbed pulse pressure is associated with significant alterations in la rge conduit arteries involving hypertrophy of central and peripheral l arge vessels and increased values of operational stiffness and altered wave reflections which return during the systolic (and not the diasto lic) component of the aortic blood pressure curve. Sodium sensitivity is commonly observed in these patients, so that low doses of diuretics correct the increased pulse pressure, particularly in those with norm al or low plasma renin activity. Conclusions Although strong interacti ons may be observed between the pulsatile component of blood pressure and the arterial changes in hypertension, much more research is requir ed before a clear-cut cause-effect relationship can be established bet ween these two variables. With the exception of diuretic therapy in th e elderly, there are at present no treatments that can selectively red uce pulse pressure or reverse the arterial changes or both in patients with essential hypertension and a disproportionate increase in systol ic blood pressure.