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The danger of Venous Thromboembolic Disease

Last Modified: July 23, 2021

Heart Health


This post was written by Bill Wilson, MD, PPG – Cardiology.

Usually when we cut or injure ourselves, our blood will clot, or thrombose, to stem the bleeding and help the wound to heal. We depend on this natural protective mechanism for our survival.  But sometimes, and more often than we realize, this protective process goes awry, and blood clots form spontaneously in unwanted places. This is called acute Venous Thromboembolic Disease (VTED).

In 2016, VTED was recognized by the U.S. Surgeon General as a major public health problem.  VTED is perhaps more commonly known by the names applied to the two most common locations for these clots, deep vein thrombosis (when the undesirable blood clots form in the veins of the legs) and pulmonary emboli (when the clots travel or embolize from the leg veins to the lungs). 

Who’s at risk?

VTED is common and is associated with reduced survival and significant healthcare costs. It also recurs frequently. It is a complex disease and there are undoubtedly both acquired and inherited tendencies for some individuals to form these blood clots. 

There are many VTED risk factors than can occur in anyone, including:

  • increasing age
  • obesity
  • hospitalization for surgery or medical illness
  • outpatient leg or joint surgery
  • nursing home confinement
  • active cancer
  • trauma or fracture
  • immobility or leg paralysis for any reason
  • pregnancy
  • oral contraceptives
  • hormone replacement therapy

Finally, and frustratingly, VTED can occur for no identifiable reason.

The risks

Deep vein thrombosis (DVT) is usually recognized acutely as a swollen, painful, and warm leg or foot. The affected limb is often discolored and red or dusky, even at times bluish. It is usually not white, nor pale or cool to the touch. It can be dangerous not only because of the acute pain and swelling but also because it can damage the leg veins permanently leading to chronic unsightly swelling.

The most feared complication of DVT is pulmonary emboli, when the blood clot in the leg migrates and lodges in the blood vessels of the lungs causing severe shortness of breath, chest pain and possibly death. Because of this relationship, DVT and pulmonary emboli (PE) are often lumped together and called VTED.

How common is VTED?

The average annual incidence rate of overall VTED (both DVT and PE) ranges from 100 to 200 per 100,00 persons. The incidence rate is similar to that of stroke. The incidence rates markedly increase after the age of 60-65. That said, VTED can certainly afflict individuals younger than 60, particularly those with the risk factors mentioned above. For example, the incidence is notably high in women of child-bearing years and in young women on birth control pills. The percentage of all VTED events that are due to no identifiable cause is roughly 25-30%. In these current times, we would be remiss not to mention that acute VTED is extremely common with COVID-19 viral infection and is often a major aspect of the illness.


VTED is a treatable disease. The cornerstone of therapy is to begin anticoagulation with blood-thinner drugs as soon as possible after diagnosis. The idea is that blood thinners prevent the formation of further clots and prevent the extension of existing clots. This allows the body’s natural defense mechanisms to slowly dissolve the initial blood clots. 

The prognosis for recovery is usually good if the blood thinners can be started quickly and if the offending risk factors can be removed. The blood thinners need to be chosen carefully and monitored closely to avoid the treatment complication of unwanted bleeding. Rarely, if the blood clots to the lung are large and life-threatening, the patient needs to undergo emergency treatment with very strong blood thinners delivered directly into the lung or mechanical removal of the clots via catheter-based interventions.

The blood-thinner medications have evolved and improved considerably over the past 10 years.  The main-stay drug for many years (and still used commonly) is heparin, which can only be given as a continuous IV infusion and thus requires hospitalization. Historically, heparin was gradually switched over to warfarin for long-term oral use prior to the patient leaving the hospital. Warfarin is a difficult drug to use as it requires frequent monitoring of drug levels and has many adverse drug and food interactions. 

The newer direct oral anticoagulants, such as apixaban and rivaroxaban, are gradually replacing warfarin since they are safer, more effective and easier to use. Because the newer direct oral anticoagulants exert their treatment immediately, many patients with acute DVT or PE can now be treated as out-patients without any hospitalization.

That, of course, is good but a robust system needs to be in place for close out-patient follow-up. To answer that need, we see these patients very soon following their diagnosis in our Clinical Anti-Thrombotic Therapy Service (CATS) Clinic so that we can help them through their treatment and recovery phase.

If you are worried about your risk for VTED, speak with your primary care provider or cardiologist. If you are experiencing any concerning symptoms, seek medical care immediately. 


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