FIGURE 1.
Analyzing viscoelastic properties of aortic segments using pressure-diameter tracings, generated from the ROTSAC setup. (A) A raw “pressure-diameter” tracing of a single distension cycle of an aortic segment between 80 and 120 mmHg. The tracing depicts a viscous component (i.e., hysteresis) as well as an inertial component. (B) Removal of the inertial component of the raw tracing by manual iteration of the inertial modulus (EM). This results in a pressure-diameter curve with clear hysteresis. (C) Removal of the viscous component (/hysteresis) by manual iteration of the viscous modulus (Eη) after having removed the inertial component. When the minimum area of hysteresis is reached, a pure elastic pressure-diameter is obtained. The slope at 100 mmHg of the resulting curve is considered as the elastic modulus (EE). The values of EM and Eη at the minimum area of hysteresis are measures of the total amount of inertia and wall viscosity, respectively.