The effects of hydrostatic pressure on the elastic properties of cat veins.

Abstract

Simultaneous measurements of pressure and volume were made on seven isolated external jugular veins and four femoral veins from cats. The measurements were made before and after the veins were held at an intraluminal pressure of 800 mm H2O. Circumferential tensions were calculated from Laplace's law (tension = pressure × radius). After being held at 800 mm H2O for periods of time up to 18 h, the resting radius of the vein increased and it became less distensible. Possible implications of these results concerning varicose veins are discussed. Since tension = pressure × radius, then as the radius increases and the pressure stays constant (as in varicose veins), the tension increases. If tension causes varicose veins then a vicious circle is set up which may result in the development of very severe varices.