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06.02.2019 Feature Article

Blood Clots: Deep Vein Thrombosis (D.V.T.) and Pulmonary Embolism

Blood Clots: Deep Vein Thrombosis (D.V.T.) and Pulmonary Embolism
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The Blood clotting mechanism is necessary to stop unnecessary bleeding and subsequent blood loss from injuries.

Occasionally, blood may clot spontaneously, in the veins. When a blood clot (thrombus) occurs in the large, deep veins, the term Deep Vein Thrombosis (D.V.T.) is used.

The veins in the Leg veins are the most frequent sites for clot formation. Clots may also occur in the veins of the thigh, pelvis and upper arms.

When detected early, DVTs are treatable. When left untreated, a DVT could have debilitating consequences.

Who Is at Risk For a DVT?
Anyone could be at risk for a DVT.
Individuals may be at higher risk, because they do have at least one or more of the following risk factors simultaneously.

. Conditions associated with slow Blood Flow

. Those Confined to Beds: those on Hospital admissions and those who have had recent surgical operations. (These conditions are the Most Common risk factors for a D.V.T).

. After an injury when movement is limited, examples include persons placed leg Casts.

. Sitting still in one position for more than 4 hours as observed in those traveling by Air and Automobiles, especially when they have crossed their legs.

. Women using estrogens (estrogens promote clot formation) as observed in

. Women on Estrogen Birth control pills, more so when they smoke nicotine

. Pregnant Women and up to three months after delivery

. Menopausal women on Estrogen replacement therapies.

. Traumas affecting the integrity of the deep veins. This condition is observed in those who have had

. Bone fractures
. Major surgery in their Abdomen, Pelvis and Legs within the past three months.

. Chronic medical illnesses
. Those with heart failure
. Those with chest and lung diseases
. Those with nephrotic syndrome.
. Those with active cancer or those treated for cancers, recently.

. Other risk factors for D.V.T. include the following:

. Those who are Overweight or Obese
. Those with a Previous history, or a Family history of DVT or Pulmonary Embolus (P.E.)

. Those with Acquired or Genetically inherited clotting disorders.

. Those aged 40 years and over have increased risk for D.V.T.

. Those with tortuous Varicose veins
. Those who Smoke nicotine
. Those with catheters placed in their large veins
. Swelling of a leg or arm (very specific for DVT)
. Pain, Tenderness, in the leg or arm
. The skin over the swelling feels warm to the touch and red (dark in darker skins)

Not all persons with DVT, have all the symptoms.
. Pain in the calf when the foot is flexed dorsally towards the shin

. Affected vein may thicken and feel cord-like
. The Overlying skin may have a different color (red or dark)

1.Most DVTs are small and resolve spontaneously without complications.

2. If a large DVT is not recognized promptly and treated, the clot may dislodge and travel in the circulation from the person’s leg to the lungs. A floating clot (Embolus) in the circulation may clog and block the lung circulation; a condition known as Pulmonary Embolism or P.E. If the clot is small, early intervention can help the affected persons to recover.

Larger clots can block the blood flow to large segments of the lungs; this can lead to a shortage of Oxygen and death; P.E requires Emergency interventions.

3. In a third of persons with a DVT, the clots may damage the valves of the veins. A backflow of venous blood into the legs leads to: leg swelling, leg pain, skin discoloration and leg ulcers. This is known as post-thrombotic syndrome (PTS). Severe cases of DVT may lead to many disabilities.

A DVT may be diagnosed with one of two laboratory tests:

1.) A blood test (the D-Dimer test). D-Dimer is a substance in the blood that increases in persons with DVT and PE.

2.) Duplex Ultrasound of the Leg veins. to determine clot formation, and clot progression.

Those with DVT restricted to the Calf veins only, and with minimal symptoms, may need duplex ultrasound at 5-7 days intervals, to monitor clot progression, for 2 weeks. They do not require anticoagulants.

Anticoagulants (Blood Thinners): Block new clot formation but they do not remove formed clots.

. Heparin: Unfractionated and the Low molecular weights (LMW) heparin

. Factor Xa inhibitor: fondaparinux (given by subcutaneous injection)

Apixaban and Rivaroxaban (both given as oral tablets and are known as direct oral anticoagulants (DOAC)

. Vitamin K inhibitors: Warfarin (Coumadin) given as oral tablets

Heparin, including LMW heparin, or fondaparinux are the initial blood thinners which are given for 5-10 days; followed with either Warfarin or one of the two DOAC medications.

The DOACs can be started immediately after DVT has been diagnosed. Unlike warfarin, periodic clot monitoring is not needed for DOAC.

Those taking Warfarin need regular blood tests to monitor their clotting system.

Duration of Anticoagulants therapy.
. When the DVT is precipitated by a known factor, doctors continue anticoagulants for a minimum of 3months.

. When the DVT (a.) is precipitated by either unknown factors, or unmodifiable known factors (b.) occurs in a knee or a thigh vein, then prolonged anticoagulation is indicated with annual reassessments.

. For those with active cancers and DVT, anticoagulation is continued, indefinitely.

Other Helpful Medications/interventions
Aspirin Use:
Aspirin is great for clot prevention in the Arteries, but aspirin is not so good at preventing clot formation in veins. Aspirin is not recommended to be taken for routine DVT prevention. There is evidence, however, that during an elective knee/hip surgery Aspirin could be used for DVT prevention.

Elastic Stockings:
Those with PTS, below knee Elastic stockings help to reduce leg swelling and pain.

Early ambulation
Once anticoagulants have been initiated, and pain is controlled, Early ambulation helps people with DVT to feel better.

PE is a leading cause of deaths in women after childbirths. Early detection and treatment prevent deaths. Left untreated, and depending on how large the clot is, a P.E. may clog the arteries of the lungs and prevents the lungs from exchanging tissue carbon dioxide for atmospheric oxygen.

. Fast heartbeat/ pulse
. Sudden Shortness of breath
. Sharp Chest pain worse on taking Deep breaths
. Cough that may have blood in phlegm.
. Anxiety
. Very low blood pressure associated with lightheadedness and fainting.

. Wheezing
Doctors may do the following tests to arrive at a diagnosis of pulmonary embolism.

. Blood test for D-Dimers
. Duplex Sonogram of the extremities to find clots in the leg veins

. Computerized Tomography (CT) Angiogram of the chest, to get a picture of the pulmonary arterial circulation. CT Angiogram is the preferred test for PE.

Persons with Acute P.E, need to be treated and monitored closely in the hospitals. Depending on the underlying medical conditions, treatment may be with medications, and or by surgical interventions

. Anticoagulants with blood thinners: Warfarin, Heparin (Unfractionated and the Low molecular weights), Fondaparinux

. Thrombolytics (clot dissolvers) like Tissue Plasminogen Activator (TPA). This is indicated for those with PE and low blood pressure, and in the younger persons with little risk for bleeding

. Clot or Embolus in the Pulmonary Artery may be removed with a pulmonary catheter

. A surgical intervention during which a Filter to trap clots from the legs and lower abdomen is placed on the inferior Vena Cava (Vein filter). A vein filter placement is reserved for those with, or at risk for bleeding problems.


If your travel duration would be longer than 4 hours, the following activities are recommended.

. Stand up and walk around every hour or two.
. Wear loose-fitting, comfortable clothing
. Flex and extend the ankles and knees periodically, avoid crossing the legs, and change positions frequently while seated.

. Consider wearing knee-high compression stockings
. Avoid sleeping pills and sedatives that could impair your ability to move around.

The best way to avoid developing blood clots is to Reduce the risk factors.

After knowing the risk factors for DVT, be on the lookout for the signs and symptoms of DVT.

. Exercise regularly. Sit less, Exercise more.
. Stay Hydrated. (Dehydration promotes clot formation) Drink fluids for adequate hydration. Alcohol causes dehydration, avoid it.

. Maintain a good weight and keep your belly flat.
. Stop smoking
. Do not wear clothes that are too tight.
. Talk to your doctor about personal or family history of blood clots before having surgeries and hospital admissions.


  1. Up To Date: Tips to avoid lower leg swelling and DVT during prolonged travel

Alex Sarkodie MD
Alex Sarkodie MD, © 2019

Alex Sarkodie,MBChB has over 30 years experience in the field of Medicine Column Page: AlexSarkodie

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