Arterial Hemodynamics in Hypertension

This paper reports mechanisms responsible for alterations in arterial hemodynamics in hypertension. Hypertension results from increased peripheral resistance, but the major changes in the pulse are a consequence of the accompanying decrease in arterial distensibility, whether this is due to the elevated mean pressure per se or to degeneration of the normal components of the arterial wall. Decreased distensibility increases characteristic impedance in the ascending aorta and through its effects on wave velocity causes shift of impedance curves to higher frequencies. This disturbs the normally favorable relationship between the components of the ventricular ejection wave and the impedance presented to the ventricle and results in increased pulsatile energy losses in the vascular system. At the same time there are changes in the harmonic components of the ascending aortic pressure wave which lead to increase in amplitude and characteristic alterations in contour. Decreased arterial distensibility causes a shift of peripheral/central pressure amplification curves to higher frequencies. As a result of this and the altered harmonic content of the ascending aortic pressure wave, there is little amplification or change in contour of the pressure wave between the ascending aorta and peripheral arteries.