Influence of arterial pulse and reflected waves on blood pressure and cardiac function.

An integrated view of the role of arterial blood pressure in cardiovascular physiology should consider both the steady (mean blood pressure) and pulsatile (systolic, diastolic, and pulse pressures) components. This brief overview describes the important factors influencing these components, with emphasis on the consequences of arterial stiffening. In addition to their conduit function, arteries also perform a cushioning function that transforms the pulsatile flow generated by contraction of the left ventricle into steady flow at the periphery. Arterial compliance is a principal determinant of arterial blood pressure and is both pressure dependent and affected by vascular biomechanics. Other important factors that affect the steady and pulsatile components of blood pressure include ventricle performance, peripheral resistance, pulse wave velocity, and the timing of pulse wave reflections. Ageing and hypertension are important factors that contribute to reductions in arterial compliance. Important functional effects of this are that both the amplitude of the arterial pulse wave and pulse wave velocity increase, causing an early return of reflected waves from the periphery to the aorta. This may boost aortic and left ventricular pressures during systole at the expense of diastolic pressure, which is reduced. Studies have shown that stiffening of arteries and the associated increase in systolic and pulse pressures are important cardiovascular risk factors. Patients with an increased risk of cardiovascular events associated with such changes should be identified and receive appropriate therapeutic interventions.