Post-Thrombotic Syndrome

What is Post-Thrombotic Syndrome?

Nathalie Routhier MD and Susan R. Kahn MD MSc
Thrombosis Program, Jewish General Hospital, McGill University, Montreal, Canada

What is the post-thrombotic syndrome (PTS)?

While some people who have had a deep vein thrombosis (DVT) or blood clots in the leg recover completely, others may be left with symptoms and physical signs in the affected limb that are collectively known as the post-thrombotic syndrome (PTS). Overall, PTS occurs in 20-40 percent of patients after an episode of lower extremity DVT, making it a common complication. A patient can still have PTS even though they receive appropriate anticoagulant treatment (blood thinning treatment) for DVT.

Why is PTS a problem?

PTS is a frequent side-effect of DVT and while symptoms can come and go over time, it is a chronic, lifelong condition. PTS leads to patient suffering and disability, and is costly to society. Severe PTS can cause venous ulcers that are painful, difficult to treat and can occur in 5-10 percent of patients who have had a DVT.

Why does PTS occur?

When a clot forms in a vein, the valves inside the vein can be damaged by the clot and/or by the surrounding inflammation. The damaged valves can permit back-sliding of the blood into the lower leg, and the residual clot can block the return of blood from the leg veins back to the heart. This results in increased venous pressures (venous hypertension) in the leg.

What are the symptoms of PTS?

Typical symptoms of PTS include leg pain, aching, heaviness or tiredness, swelling, cramping and itching. The number and type of symptoms may vary from person to person. Symptoms typically worsen with standing or walking, and improve with rest and leg elevation. PTS may cause a bluish discoloration of leg/foot/toes, especially with standing. Other changes may occur in the appearance of the leg. These changes may include leg swelling, brownish skin color, formation of new varicose veins, dry flaky skin or redness(eczema), hardening of the skin, and leg ulceration (typically above the ankle bone on the inside of the leg). PTS usually develops within the first six months after a DVT occurs, but it can also occur up to two years after the clot.

What are the risk factors for developing PTS after DVT?

It is difficult to predict which patients who have had a DVT will develop PTS. Nevertheless, several factors appear to increase a person’s risk. These include more extensive forms of DVT occurring higher up in the leg veins, obesity, and having another DVT in a leg previously affected by DVT. Older age and less effective anticoagulant treatment for the initial DVT may also be risk factors. Recent studies show that persistence of pain and swelling one month after having a DVT is associated with a higher risk of developing PTS.

Prevention and treatment of PTS

Wearing compression stockings (knee-length, 30-40 mm Hg gradient compression) daily for two years after having a DVT has been shown in some studies to reduce the risk of developing PTS by 50%. However, this may be cumbersome in some patients. Research on the benefit of compression stockings for the prevention of PTS is still ongoing. Preventing recurrence of DVT is also important. DVT can best be prevented by using anticoagulation for an appropriate length of time following a first DVT and taking appropriate precautions during high risk periods once the patient stops taking anticoagulants.

If a patient already has PTS, elevating the legs and using compression stockings during the day may reduce leg swelling and pain. Medication may help alleviate pain. Intermittent compression devices, which are worn on the outside of the leg and periodically squeeze the leg, may be used to relieve swelling for severe cases of PTS. It is not yet known whether weight loss or specific exercises to strengthen the leg muscles are beneficial in treating PTS. Surgical or endovascular vein opening procedures of deep leg vein(s) may be beneficial for the treatment of PTS in patients whose veins are chronically blocked.

In conclusion, current options to treat PTS are limited. More research is needed on better ways to both prevent and manage PTS

About the authors:

Nathalie Routhier, MD is Assistant Professor at University of Montreal. She trained as a Fellow in Thrombosis at the Jewish General Hospital in Montreal and completed a Master`s Degree in Neuroscience at McGill University. She is a working as staff in Internal Medicine specialized in Thrombosis at Sacré-Coeur Hospital in Montreal.

Susan R. Kahn, MD is an internist and clinical epidemiologist based at the Jewish General Hospital in Montreal, where she is Director of the Thrombosis Program. She also is Professor with Tenure in the Department of Medicine and Associate Member in the Department of Epidemiology and Biostatistics, McGill University. Dr. Kahn holds a National Research Scholar award from the Fonds de la recherche en santé du Québec, has been awarded numerous peer-reviewed research grants and has published and presented widely in the field of thromboembolism.

Post-Thrombotic Syndrome section was last modified: October 27, 2009 - 02:05 pm