Deep vein thrombosis (DVT) is the formation of
a blood clot, known as a thrombus, in the deep
leg vein. It is a very serious condition that
can cause permanent damage to the leg, known as
post-thrombotic syndrome, or a life-threating
pulomnary embolism. In the United States alone,
600,000 new cases are diagnosed each year. One
in every 100 people who develops DVT dies. Recently,
it has been referred to as "Economy Class
Syndrome" due to the occurrence after sitting
on long flights.
The
deep veins that lie near the center of the leg
are surrounded by powerful muscles that contract
and force deoxygenated blood back to the lungs
and heart. One-way valves prevent the back-flow
of blood between the contractions. (Blood is squeezed
up the leg against gravity and the valves prevent
it from flowing back to our feet.) When the circulation
of the blood slows down due to illness, injury
or inactivity, blood can accumulate or "pool"
which provides an ideal setting for clot formation.
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Risk Factors
* Previous DVT or family history of DVT
* Immobility, such as bed rest or sitting for
long periods of time
* Recent surgery
* Above the age of 40
* Hormone therapy or oral contraceptives
* Pregnancy or post-partum
* Previous or current cancer
* Limb trauma and/or orthopedic procedures
* Coagulation abnormalities
* Obesity
Symptoms
* Discoloration of the legs
* Calf or leg pain or tenderness
* Swelling of the leg or lower limb
* Warm skin
* Surface veins become more visible
* Leg fatigue
Post-thrombotic
Syndrome
Post-thrombotic
syndrome is an under-recognized, but relatively
common sequela, or aftereffect, of having DVT
if treated with blood thinners (anticoagulation)
alone, because the clot remains in the leg. Contrary
to popular belief, anticoagulants do not actively
dissolve the clot, they just prevent new clots
from forming. The body will eventually dissolve
a clot, but often the vein becomes damaged in
the meantime. A significant proportion of these
patients develop permanent irreversible damage
in the affected leg veins and their valves, resulting
in abnormal pooling of blood in the leg, chronic
leg pain, fatigue, swelling, and, in extreme cases,
severe skin ulcers. While this use to be considered
an unusual, long-term sequela, it actually occurs
frequently, in as many as 60-70 percent of people,
and can develop within two months of developing
DVT. There is increasing evidence that clot removal
via interventional catheter-directed thrombolysis
in selected cases of DVT can improve quality of
life and prevent the debilitating sequela of post-thrombotic
syndrome.
Pulmonary
Embolism
Left
untreated, a deep vein thrombosis (DVT) can break
off and travel in the circulation, getting trapped
in the lung, where it blocks the oxygen supply,
causing heart failure. This is known as a pulmonary
embolism, which can be fatal. With early treatment,
people with DVT can reduce their chances of developing
a life threatening pulmonary embolism to less
than one percent. Blood thinners like heparin
and coumadin are effective in preventing further
clotting and can prevent a pulmonary embolism
from occurring.
* It is estimated that each year more than 600,000
patients suffer a pulmonary embolism.
* PE causes or contributes to up to 200,000 deaths
annually in the United States.
* One in every 100 patients who develop DVT die
due to pulmonary embolism.
* A majority of pulmonary embolism are caused
by DVT.
* If pulmonary embolism can be diagnosed and appropriate
therapy started, the mortality can be reduced
from approximately 30 percent to less than ten
percent.
Symptoms
of Pulmonary Embolism
The
symptoms are frequently nonspecific and can mimic
many other cardiopulmonary events.
* Shortness of breath
* Rapid pulse
* Sweating
* Sharp chest pain
* Bloody sputum (coughing up blood)
* Fainting
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