The Venous System

The venous system is a network of pipes that carries blood towards the heart against gravity.  The flow of blood toward the heart is maintained by one-way valves in the veins and the pumping action of the calf muscles.


The valves are like curved doors, or cups, spaced at intervals along the inside wall of the vein.  They open as blood flows toward the heart and close to prevent blood from dropping back to the feet.  When the valves are healthy, they close tightly (competent valves), but when they are diseased they allow leaking (incompetent valves).

Pumping Action

The pumping action of the calf muscles against the veins helps push blood against gravity towards the heart.

Type of Veins

There are two main types of veins in the legs: the deep veins and the superficial veins.  The deep veins lie deep in the legs and are enclosed by muscle.  These veins return the majority of the blood to the heart.  The superficial veins are located near the surface of the skin and have the least muscle support.

DVT - Deep Vein Thrombosis

Deep vein thrombosis is a blood clot that partially or completely blocks the flow of blood through a vein.  It occurs more commonly in the veins in the legs than in the arms.

Causes of DVT

This type of blood clot is believed to be cause by three factors:

Trauma causing injury to the vein wall

Slowing down or stopping of blood flow in the veins (venous stasis) with resulting pooling of the blood An abnormal blood clotting system

Risk Factors for Developing DVT

  • Traumatic injury

  • Immobility

  • Smoking

  • Pregnancy

  • Hormonal drug therapy

  • Past history of clotting

  • Obesity

  • An age over 40

  • Varicose veins

  • Cancer

  • Surgery

  • Blood disorder

Symptoms of DVT

When obstruction to the venous flow is minimal, there may be no symptoms.  As obstruction increases, symptoms will occur:

  • A sudden increase in size of an arm or leg

  • Enlargement of superficial veins those closer to the skin

  • Heaviness of the affected limb

  • Pain with walking

  • The affected limb may feel warm to touch and sometimes red streaking may appear

    How is DVT Detected?

    A history and physical examination is done before testing is done.

    Non-invasive testing:

  • Doppler ultrasound - a sound wave test

  • IPG - Impedance plethysmography - measures venous blood flow.

  • Duplex scan combines sound waves and an image of the vessel.

    Invasive testing:

  • Venogram - dye is injected into a foot or groin vein to determine if a blood clot is present.

DVT Treatment Medical treatment

Anticoagulant medications are the primary treatment for deep venous thrombosis.  These drugs can be given intravenously in the hospital or can be taken at home orally.


  • Prevent more blood clots from forming

  • Keep the existing clot from getting bigger

  • Begin to smooth out the existing clot so it will be less likely to break off and travel elsewhere Thrombolytic drugs may be used to dissolve a blood clot.These drugs are used for immediate, short-term treatment in a hospital under careful supervision.

Other Treatment

Other methods of treatment for deep vein thrombosis include:

  • Bed rest initially - then activity is slowly increased

  • Elevation of the affected limb

  • Sometimes elastic bandages or support stockings are used

    When multiple episodes of clotting occur, a device (an umbrella) may be placed in the systemic vein the vena cava.

Coping with your Venous Disease

There are a number of ways you can improve your condition and reduce the risk of developing another blood clot.

Do not smoke - smoking increases the risk of forming blood clots.  Even 1 cigarette a day can be dangerous.

Stay active - muscles help pump the blood in the direction of the heart.

Even when in bed you should exercise the legs regularly.

When traveling you should stop frequently (at least every 2 hours), get out, and walk around to circulate the blood and get it moving towards the heart.

Avoid standing or sitting in one position for a long period of time. This causes pooling of the blood in your legs.

Rise up on your toes several times an hour.

Shift your weight from foot to foot. On plane flights walk the aisle.

Elevate your legs several times a day for at least 10-15 minutes; if you are working set aside rest periods for leg elevation. 

Raise your legs higher than the level of your heart.  This can be done by lying on the floor with your legs on a chair or against the wall and by placing several pillows under your leg while reclining in your recliner.

Avoid crossing your legs at the ankles and at the knees for any length of time.

Dress sensibly - sometimes your physician will want you to wear support stocking when awake.  These may be removed while sleeping.

Your active participation in managing your vascular disease is very important in maintaining good health.

NextGen Patient Education Material