Most of the existing models of cardiovascular system do not take into account the leakage of blood through a number of small vessels branching the main arterial trunks and called perforators. Therefore, the aim of this study is to investigate their influence on the pulse pressure waveform. Linearized, 1D computer model of a minute part of the cardiovascular system has been designed and series of simulations with and without leakage have been conducted. Blood flow in a single segment of the arterial system and pressure in vascular nodes were described by the two first order partial differential equations. A set of boundary conditions on both ends of a single vascular segment and at nodal point have been formulated. To solve the linear set of above equations, a numerical method of characteristic has been used. It was shown that the leakage reduces reflection from the peripheral resistance. The simulations have also shown a decrease of the average pressure value with increase of leakage and modification of the pulse pressure waveform. All these effects depended strongly on the assumed leakage value and practically died out when its value was reduced to about 10% of the main flow.
According to international guidelines, patients with Peripheral Artery Disease (PAD) are burdened with high
cardiovascular risk. One of the simplest, non-invasive methods for PAD detection is the ankle-brachial index (ABI)
measurement. The ABI is calculated as the ratio of systolic blood pressure at the ankle (pressure in the posterior tibial
artery or the dorsal artery) to the systolic pressure in the arm (in the brachial artery) when the body is in a horizontal
position. The physiological value of the ABI is assumed to be between 1 and 1.3; however, these limits vary from study
to study. A value less than 0.9 indicates PAD. Some authors propose also measuring the ABI on both sides of the body
to highlight possible differences in blood pressure between the opposite arterial segments.
The aim of this study was to perform a meta-analysis of the ABI diagnostic criteria used in different publications.
Additionally, ABI measurements were performed on 19 healthy patients in age ranged from 20 to 63 years. The results
showed a slight dependence between age and the differences between the values obtained from left and right sides
of the body.