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Varicose Veins Definition -
To Understand Their Effects

Grasping a varicose veins definition will enable you to better picture their influence…. Also why you would want to treat them.

A large bulging, twisted vein is very obviously varicose in everybody’s mind

But what about something that is just a little prominent and visible?  Especially if it looks quite straight.

When does it become a varicose vein?

Blood Vessel Dynamics

Your arterial flow and pressures are influenced by the pumping action of your heart.  It’s pulsatile in nature, giving the higher and lower values for your blood pressure.

After passing through your fine capillaries there is very little pressure left.  Certainly not enough to push your blood against gravity back up to your heart.  Lying down makes this return easier.  

So how does your blood manage to make its way back to your heart to be pumped onwards again?

The Body's Muscle Pump

There is an even larger pump than your heart… Your leg muscles.  Plus all the other body's muscles.

As these contract it increases the pressure in your vein.  Inside your veins are a series of one way valves.  With increased pressure your blood is squeezed through these, as they are forced open, back towards your heart.

Varicose veins definition explanation beginning with the muscle pump - in this case the calf muscle pump returning blood back to your heart.The calf muscle pump for sending venous blood back up to your heart.

Once your muscle relaxes ready for its next action the vein will expand again.  The valve leaflets fall back against each other, closing. 

Very little blood goes backwards.

Flow Revealed On Ultrasound

When I use an imaging ultrasound (or less accurately a hand-held apparatus similar to those used for listening to a baby’s heart) I can hear your blood moving one way or the other.  

Getting you to contract your muscle below the area I am listening to will do this.  It is easier to produce this action without causing you to move by me squeezing your muscle.  This creates a very similar effect.

With a colour imaging ultrasound I set up the upward flow to shown as blue.  Any reverse flow shows red. 

I can also produce a time-based graph that illustrates the relative amount of flow occurring.  

Usually there can be a small amount of reverse or backward flow just before your vein’s valve shuts.  

This will show in the on-screen colour, and as a volume either below or above the baseline, in sync with the sound.  

The horizontal line on the graph shows time in seconds and fractions of seconds.  A normal vein should have less than half a second of back flow.  Usually it is much less.

Varicose Veins Definition Revealed On Ultrasound

An abnormal or varicose vein will show reverse flow of greater than half a second.  Often it will be several seconds long.  

Gravity is dragging it back the way it has just travelled.

This occurs when your valve is not shutting adequately in response to the reverse flow - very much like a leaky tap washer!

Underlying Abnormality

Why does the valve leak?

Often you will see this explained as a damaged valve.

At times this can be so…

But usually the valve is totally normal. 

The problem is the tube (the vein) has become bigger.  The valve cannot close across its full width.  

How does your vein get larger?

This is the underlying problem with varicose veins.

Unlike arteries which you tend to see getting clogged with cholesterol and other deposits, becoming more and more narrow, veins, being relatively thin-walled, stretch.  The structure of the wall has been weakened.

This occurs for a number of reasons.  But essentially all your body’s tissues are dynamic being constantly remodelled.  Even your bones, which seem solid, do this. 

How Do Your Vein Walls Weaken?

It seems that in people who develop varicose veins their repair process is defective.  I go into some detail as to who and in what situations this occurs in a further page.

An internationally agreed technical varicose veins definition is where your valves allow reverse flow of over half a second in normal conditions.  

By this varicose veins definition it does not matter what your vein looks like or where it is situated, this prolonged reverse flow is diagnostic.

Variations And Cautions

It is possible to find some longer that five second reverse flow at points where veins join each other.  A turbulent flow is produced.  But this will be very localised.  It will be controlled, if the vein is normal, at the first vein valve.

Your vein's function dynamics can vary at times.  Strong squeezes or muscle contractions might induce some reverse flow.  But not on more usual pressures.  

Time of day, hydration, and the warmth of the room your vein is tested in can produce variations too.

But once fully established as a problem the varicose veins definition will be met in most situations.

I will share more explanations under vein treatments which will explain what options you have to help overcome a vein with refluxing or backwards flow.

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