aree scientifiche

Conclusions

Thanks to the high prevalence of FVD, the proposed technique provides an opportunity to treat a larger number of cases affected by primary or post-thrombotic deep venous reflux.

39) PUSKÁS A. et Al.:HAEMODYNAMIC MAPPING OF CHRONIC VENOUS INSUFFICIENCY:THE CONCEPT OF SHUNTS

VÉNÁK BETEGSÉGEI Érbetegségek, XXIII. évfolyam 4. szám, 2016/4.

ABSTRAC

It is well-known that the diagnostics of chronic venous insufficiency has been revolutionised by the introduction of duplex ultrasound. Refined manoeuvres and techniques contribute to the clarification of anatomical and haemodynamic details which are necessary for planning different steps in treatment. According to fluid dynamic science, the shunt is a pathway which diverts the flow into another channel system. Veno-venous shunts are venous tubes which diverts the venous blood from the physiological backflow through an insufficient veno-venous connection, which means a large extra amount of blood burdens these shunting venous channels. These shunts cause a flow and pressure overload, which results in high venous transmural pressure in this part of the venous system, which causes varicose dilatations, and symptoms and complaints for the

patient. According to the haemodynamic concept, these phenomena are the consequences of hight transmural pressure. This is because the extra amount of venous blood causes a faster speed of

low which changes the flow from laminar to turbulent. As a consequence of the turbulent flow, the pressure on the venous wall increases, which slowly dilates the lumen of the vein. With the usage of duplex ultrasound the following shunt elements can be identified:

(1) Escape point, where venous blood escapes from the deep to the superficial layers, which is opposite the physiological direction of flow.

(2) Shunt pathway, comprising all venous segments which make up the shunt and drains the superfluous venous blood burdening this system.

(3) Re-entry point drives the extra blood back to

the deep veins.

Four basic shunt types and some further subtypes can be distinguished by venous haemodynamics. Ultrasound mapping of them is a key point of therapeutic strategy. A good map is mandatory for a good treatment.

The basic shunt types are the following:

a) Closed shunt – venous blood starts its way at the escape point and goes to the re-entry point and again to the escape point, which means the recirculation of blood between these venous

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