Some epidemiologic and experimental studies have raised the possibility that pulse pressure may be a determinant of vascular structure. In addition, 24-h blood pressure variability has been reported to be more closely related to the severity of target-organ damage than to casual blood pressure in hypertensive patients. These data suggest that when the effects of mechanical stress on the arterial wall are evaluated, it is necessary not only to take into account steady (i.e., mean) parameters but also to consider pulsatile parameters and the variability of steady and pulsatile parameters. Pharmacologic data suggest that reduction of pulse pressure during antihypertensive treatment may be a factor in prevention of altered vascular structure during chronic hypertension. Improving arterial compliance by specific antihypertensive treatment is a way to reduce pulse pressure and therefore to contribute to this prevention. Whether normalization of blood pressure variability by antihypertensive treatment is also a means of preventing altered vascular structure remains to be determined.