Postthrombotic syndrome (PTS) is a problem that can develop in nearly half of all patients who experience a deep vein thrombosis (blood clot) in the leg.1,2 PTS symptoms include chronic leg pain, swelling, redness, and ulcers (sores). It can be expensive to treat and make it difficult for you to get around, and the pain and discomfort can make your life less enjoyable. The best thing to do is to prevent this problem whenever possible.
What is PTS?
The veins deep in our legs have tiny valves that control the direction of blood flow. A blood clot in a leg vein can cause inflammation and block blood flow, causing damage to these valves. When valves are damaged, they can become leaky, allowing fluid to pool around the ankle. A blood clot that does not fully heal can also block blood flow. This makes the leg painful, swollen, and sometimes red (the Figure).3 As PTS worsens, poor blood flow in the leg can cause leg ulcers, which can be difficult to treat.2,4
How Do I Know if I Have PTS?
Having a blood clot above the knee (proximal deep vein thrombosis)
Having more than 1 blood clot in the same leg more than once
Still having blood clot symptoms 1 month after being diagnosed with the blood clot
Being very overweight
Having trouble keeping your blood thinner levels where they should be during the first 3 months after starting blood thinner medication
Pain, aching, and swelling in the leg (which can be worse after walking or standing for a long time and better after resting or raising the leg)
An ulcer (sore) on the leg
If you have any of these symptoms, you should see your physician. A physician can decide if you have PTS on the basis of these symptoms. No special testing is needed to find out if you have PTS.2,4
The best way to prevent PTS is to prevent the blood clot from occurring in the first place. Some patients have a higher risk of getting blood clots, especially patients in the hospital who have had recent surgery or are confined to bed. Patients are often given compression boots, stockings, or medicine to prevent blood clots while in the hospital and even after discharge.8 If you are in the hospital and are not given any of these things, you should ask your doctor if you need blood clot prevention.
In a patient who has a blood clot in the leg, elastic compression stockings help keep fluid from pooling (collecting) in the ankle (edema).2,9,10 Elastic compression stockings are made of a special elastic. They are very tight at the ankle, and the tightness lessens as the stockings move up the leg. This tightness (compression) helps the leg muscles squeeze the fluid back up in the proper direction, improving blood flow and decreasing leg pain.11 You should start wearing these stockings as soon as possible after being diagnosed with a blood clot and should continue wearing them for at least 2 years.2,12
Compression stockings come in different strengths (levels of tightness). These levels of tightness are measured in millimeters of mercury (mm Hg). To obtain the right level of tightness to prevent PTS (30 to 40 mm Hg), you need a prescription from your doctor. You can get these stockings at some pharmacies or at most medical supply stores. The staff selling you the stockings should measure your leg so that you get the right size. The stocking should be worn during the day on the leg with the blood clot. It may be taken off at night (Table 2).
Patients who get PTS are usually given stockings with a higher strength (30 to 40 mm Hg). If this is not effective at reducing swelling and other leg symptoms, a higher strength might be prescribed. Patients may also be given another type of device that puts pressure on the leg to improve blood flow.2,12 Patients who get leg ulcers because of PTS also need wound care, and a prescription medication called pentoxifylline may help heal the ulcer.2,12
Here are some Internet links that will give you more information about PTS and the use of compression stockings:
Combs J. To hose or not to hose, that is the question: North American Thrombosis Forum. Available at: http://natfonline.org/eThrombosis/?P=482.
Bussey, HI. ClotCare online resource. Available at: http:// www.clotcare.com/clotcare/faq_postthromboticsyndrome.aspx.
Routhier N, Kahn SR. Venous Disease Coalition: post-thrombotic syndrome. Available at: http://www. venousdiseasecoalition.org/diseaseinfo/pts/.
National Alliance for Thrombosis and Thrombophilia. Postthrombotic syndrome (venous stress disorder): an in-depth guide for patients and health care providers. Available at: http://www.stoptheclot.org/natt_publications/post_thrombotic_syndrome.pdf.
We are indebted to Kim Mahoney for manuscript and figure preparation.
Dr Kahn holds numerous peer-review funded grants; receives research support from Sigvaris; is on the speakers’ bureau for Pfizer, Sanofi, and Leo Pharma; and is on the advisory board for Sanofi, Bayer, and Boehringer-Ingelheim. Dr Vazquez reports no conflicts.
Kahn SR. How I treat postthrombotic syndrome. Blood. 2009; 114: 4624–4631.
Kahn SR, Shrier I, Julian JA, Ducruet T, Arsenault L, Miron MJ, Roussin A, Desmarais S, Joyal F, Kassis J, Solymoss S, Desjardins L, Lamping DL, Johri M, Ginsberg JS. Determinants and time course of the postthrombotic syndrome after acute deep venous thrombosis. Ann Intern Med. 2008; 149: 698–707.