Original
EFFECTS OF PRESSURE WAVE PROPAGATION ON VESSEL VISCO-ELASTICITY: AN IN VITRO STUDY
2012 Volume 72 Issue 5 Pages 553-559
Details
2012 Volume 72 Issue 5 Pages 553-559
Visco-elasticity is a rheological parameter which describes blood flow properties of the vasculature. Visco-elasticity of small caliber prosthesis is considered to be an important factor for long-term patency. However, the relationship between visco-elasticity and prosthesis caliber has not been clarified. In our study, the cross-section area and internal pressure of expanded polytetrafluoroethylene (ePTFE) grafts were measured by laser sensor and pressure catheter. Distensibility was calculated from the cross-section area and internal pressure. Viscocity was calculated from the hysteresis loop (cross-section area and pressure relationship) and internal pressure. Both data were measured at orifice and transmission distance at 10cm, 20cm and 30cm. Two types (5mm and 10mm caliber) of ePTFE grafts were examined. Measurements were performed under mean internal pressure hold at 100mmHg. Distensibility of 10mm ePTFE graft at orifice and transmission distance of 10mm, 20mm, 30mm were 9.1 × 10-5mmHg-1, 5.6 × 10-5mmHg-1, 4.0 × 10-5mmHg-1 and 3.5 × 10-5mmHg-1. Distensibility of 5mm ePTFE graft were 2.8 × 10-5mmHg-1, 2.6 × 10-5mmHg-1, 1.9 × 10-5mmHg-1 and 1.1 × 10-5mmHg-1, respectively. Viscosity of 10mm ePTFE graft at orifice and transmission distance of 30mm were 2.6mmHg and 0.81mmHg and those of 5mm ePTFE graft were 0.49mmHg and 0.26mmHg, respectively. Pulse wave velocity of both ePTFE grafts was measured from 20 to 40 m/s using a laser sensor. Improvement of the visco-elasticity should be considered for the long-term patency of small caliber prostheses.
