BACKGROUND Although systolic and diastolic blood pressure and cardiovascular risk are directly related in epidemiologic studies, the results of large therapeutic trials in mild to moderate hypertension have indicated that the prevention of cerebrovascular accidents was much more effective than that of coronary ischemic accidents. Actually, a significant decrease in coronary events was observed only in aged populations in which systolic (and not diastolic) blood pressure was chosen as criterion of entry. Whether the choice of the mechanical factor (systolic or diastolic blood pressure or both) used to define hypertension might have created a bias in the studied populations remains an important question. FINDINGS Above 50 years of age, most hypertensive populations are characterized by a disproportionate increase in systolic over diastolic blood pressure, so that the pulsatile component of blood pressure is strikingly augmented. This pattern is commonly observed in old people with essential hypertension, in hypertensive subjects with advanced renal failure undergoing hemodialysis and in atherosclerotic subjects with hypertension, particularly those with atherosclerosis of the lower limbs and cerebral vessels. In all these populations, the disturbed pulse pressure is associated with significant alterations in large conduit arteries involving hypertrophy of central and peripheral large vessels and increased values of operational stiffness and altered wave reflections which return during the systolic (and not the diastolic) 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 normal or low plasma renin activity. CONCLUSIONS Although strong interactions may be observed between the pulsatile component of blood pressure and the arterial changes in hypertension, much more research is required before a clear-cut cause-effect relationship can be established between these two variables. With the exception of diuretic therapy in the elderly, there are at present no treatments that can selectively reduce pulse pressure or reverse the arterial changes or both in patients with essential hypertension and a disproportionate increase in systolic blood pressure.
