Getting the variables that represent the arterial diameter variation wave in radial artery

One of the main characteristics of illnesses like atherosclerosis and hypertension is the loss of arterial elasticity. In this article we develop two methods to determine the variables that represent the arterial diameter variation (ADV) wave in radial artery which will later allow us to study the arterial elasticity from the radial artery. For our study we use fifty three arterial diameter variation waves of normotensive men. We develop a software that automatically obtains fifty variables for each one of the ADV waves by means of straight lines on the contour of the wave. We reduce the number of variables when using Analysis Multivariate and a biological approach that expresses the increase of the propagation velocity of the pulse wave in the arterial system with age. It is important to point out that the ADV waves are identical in form to the pressure wave in the radial artery. When applying the Analysis Multivariate by means of the Principal Components Analysis and Multiple Regression to the ADV waves, the number of independent variables first decreases from fifty to sixteen with a coefficient of multiple determination R² that varies between 54% and 100% (p <;0.001), and in a second stage, when applying an empiric approach, the variables number that represent the ADV wave decreases from sixteen to seven with a coefficient of multiple determination R² that varies between 32% and 100% (p <;0.01). We have developed a low cost electronic equipment that uses a non invasive technique to obtain the ADV waves in radial artery. By means of two methods a statistical and an empiric one, we select and obtained, the seven variables that represent the ADV waves. These variables depend on the time and not of their normalized amplitude.