What are varicose veins?

Varicose veins are defined as tortuous and dilated veins where the blood flow is inverted.

This causes increased pressure in the lower veins, and it starts a vicious circle, where more pressure causes more dilatation, amplifying the reversed flow and overload.

Varicose veins are not the cause but a symptom of venous insufficiency. They involve hemodynamic causes.

In venous insufficiency, during muscle contraction, blood flows correctly, from down toward the heart. During muscle relaxation, because of valves incompetence, blood flows downward increasing the pressure, and overloading superfical veins.

In Varicose veins we have structural and hemodynamic problems: valves incompetence generates a flow inversion, from up to down and from the deep to the superficial venous system with an increase in pressure. Therefore a certain volume of blood flows in a closed circle called veno-venous shunt. There are different types of shunts, which have been classified according to their origin and characteristics.

Because of flow inversion and veno-venous-shunts*, the function of tissue drainage is no more assured: toxins that are usually eliminated by the venous system stagnate and cause inflammation, producing aching of the legs, night cramps, swelling of the ankles, edema, eczema and ulcers of the skin, and other problems.

* A veno-venous shunt is defined as a short circuit between the deep and the superficial veins where the flow direction is inverted because of valve incompetence.

Dilation depends on flow and pressure. The more compliant* the vein, the greater the dilation will be. Venous dilation regresses totally or partially when the responsible flow and pressure are reduced.

* Venous compliance is the property of the vessel to adapt its volume to differences in pressure loading.

Veins are a low pressure very compliant system. The compliance of these vessels allow for the veins to change shape with changes in pressure. By changing their shape, the veins can vary the resistance to flow.

The sapheno-femoral junction is the place where the great saphenous vein join the femoral vein, the major deep vein of the leg. The flow of blood at this junction is controlled by a one-way valve wich is designed to direct blood upward, if this valve fails to function properly, a reflux is generated.

In many cases the incompetence of the sapheno-femoral junction produces an inversion of flow along the saphenous vein, but it is demonstrated that at least 45% of varicose veins of the great saphenous vein do not originate from sapheno-femoral junction reflux: other kinds of refluxes, coming from the groin, from the perineal and/or gluteal regions can appear.

These leakage points are identified and treated by the CHIVA strategy.

Le contenu de cette page nécessite une version plus récente d’Adobe Flash Player.

Obtenir le lecteur Adobe Flash