Modern physiology designed the idea of the vascular strain wave (VPW). This wave is established by the heart through the systole and originates in the ascending aorta. Significantly sooner than the stream of blood by itself, it is then transported via the vessel walls to the peripheral arteries. There the strain wave can be palpated as the peripheral pulse. As the wave is reflected at the peripheral veins it runs back again in a centripetal fashion. Where the crests of the mirrored and the first wave meet, the stress within the vessel is increased than the genuine stress in the aorta. This idea explains why the arterial strain inside the peripheral arteries of the legs and arms is greater than the arterial pressure in the aorta, and in turn for the bigger pressures noticed at the ankle compared to the arm with usual ankle brachial stress index values.
The up and down fluctuation of the arterial stress success from the pulsatile nature of the cardiac output, i.e. the heartbeat. The pulse stress is established by the interaction of the stroke volume of the heart, compliance (capability to increase) of the aorta, and the resistance to movement in the arterial tree. By expanding below stress, the aorta absorbs some of the force of the blood surge from the heart all through a heartbeat. In this way the pulse stress is lowered from what it would be if the aorta wasn’t compliant. The loss of arterial compliance that happens with getting older explains the elevated pulse pressures found in elderly sufferers.