Last reviewed: June 3, 2026 · Compression Socks Canada Team
A deep vein thrombosis (DVT) is a serious medical event on its own. What surprises many Canadians is that the body's response to that clot can produce a longer-lasting condition called post-thrombotic syndrome, often shortened to PTS. PTS develops in a meaningful portion of people who have had a leg DVT, and it is one of the main reasons clinicians may recommend continuing graduated compression stockings well beyond the initial anticoagulation period.
This article explains what PTS is, why it happens, how it shows up in daily life, and how compression therapy is used as part of long-term management. It is general health information for Canadian readers and is not a substitute for medical advice. Anyone managing PTS should work with their physician or a vascular specialist on a personalized plan.
What is post-thrombotic syndrome?
When a clot forms in a deep vein, it damages the inner lining of the vein and, very often, the small valves that keep blood moving upward against gravity. Even after the clot is treated and the body remodels the affected segment, those valves may not work as well as they did before. Blood then pools more easily in the lower leg, pressure rises inside the vein, and the surrounding tissue starts to react. That collection of long-term symptoms is what clinicians call PTS.
The National Library of Medicine and major vascular guidelines describe PTS as a chronic condition of venous hypertension and inflammation that develops weeks to months after a DVT. Severity ranges from mild aching and swelling to severe skin changes and venous ulcers.
How common is PTS after a DVT?
Estimates vary across studies and patient populations, but PTS is widely described as common after a proximal leg DVT, with anywhere from a meaningful minority to nearly half of patients developing some degree of symptoms over the years that follow. Risk factors generally include:
- Larger or more proximal clots (those involving the thigh or pelvis).
- Recurrent DVT in the same leg.
- Persistent residual obstruction after anticoagulation.
- Higher body mass index.
- Older age.
- Inadequate use of compression therapy during the months after the DVT.
None of these are guarantees of PTS, but together they tell clinicians which patients warrant the closest monitoring and the most consistent use of compression.
Symptoms people often describe
PTS symptoms can resemble chronic venous insufficiency because the underlying mechanism — venous hypertension — is similar. Common reports include:
- A sensation of heaviness or fatigue in the affected leg, often worse later in the day.
- Aching, cramping, or throbbing.
- Visible swelling around the ankle and calf.
- Itching or burning along the inner ankle.
- Visible vein changes, including new varicosities along the calf or thigh.
- Skin discolouration, dryness, or eczema-like patches.
- In advanced cases, slow-healing wounds (venous ulcers) near the ankle.
Symptoms typically worsen with prolonged standing, long car or air travel, and warm weather. They generally ease with leg elevation, walking, and consistent use of compression stockings.
Why long-term compression matters
Graduated compression stockings apply firmer pressure at the ankle that decreases as the stocking moves up the leg. That gradient supports the calf muscle pump, encourages venous return, and reduces the volume of pooled blood in the dilated vein segments left behind after a DVT. The clinical goal is straightforward: lower the daily pressure load on a vein system that has been compromised by an earlier clot.
The role of compression in PTS prevention has been debated in the research literature, and recommendations have evolved. Many vascular guidelines and major centres, including discussions summarized by Mayo Clinic, continue to support compression as a core element of symptom control even where its preventive role is less certain. For patients who already have symptoms of PTS, compression remains one of the most consistent levers available to manage swelling and discomfort.
What pressure class is typically used?
For PTS, two pressure classes show up most often in clinical practice:
- 20-30 mmHg as an initial choice for many patients with symptomatic PTS. Browse 20-30 mmHg compression stockings.
- 30-40 mmHg when PTS is more severe, swelling is persistent, or skin changes have started. Browse 30-40 mmHg compression stockings.
Pressure class is a medical decision, not a self-service one. Higher pressure is harder to don, less comfortable, and not safe for everyone, especially in the presence of peripheral artery disease. A physician or fitter should confirm the right class for the specific leg.
Length and style choices
Knee-high stockings cover the calf where venous symptoms most often concentrate. They are the most commonly worn length for PTS. Thigh-high stockings come into play when swelling reaches above the knee, or when the original DVT involved the femoral or iliac veins. Pantyhose options exist for patients who prefer a single garment that addresses both legs and pelvic pressure together.
You can browse the DVT-focused compression collection and the blood-clot recovery collection if you want to filter by condition rather than length. For an authorized Canadian assortment from a single manufacturer, the Sigvaris and JOBST ranges both include strong PTS options.
How to wear PTS compression effectively
The practical details matter as much as the choice of stocking:
- Put them on first thing in the morning. The leg is at its smallest before you start moving around.
- Wear them throughout waking hours. Compression is not doing the same job overnight when the legs are horizontal.
- Inspect skin daily. Look for new dryness, redness, or breakdown points, especially around the inner ankle.
- Replace stockings every three to six months for daily wear. Elastic fibres relax with washing and use, which lowers actual delivered pressure.
- Wash according to the manufacturer's instructions. Most are machine washable on a gentle cycle and air dry best.
Habits that work alongside compression
Long-term PTS management benefits from a combination of strategies:
- Walking. The calf muscle pump is one of the most effective ways to move venous blood upward. Short, frequent walks beat one long sedentary stretch.
- Leg elevation. Elevating the affected leg above heart level for 15 to 20 minutes a few times a day relieves pressure quickly.
- Weight management. Lower body weight reduces venous load.
- Skin care. Moisturisers preserve the skin barrier, which becomes more important as PTS progresses.
- Anticoagulant adherence. Continuing prescribed anticoagulation as directed protects against recurrent DVT, which is one of the strongest predictors of worse PTS.
The Thrombosis Canada patient resources cover practical do's and don'ts for life after a DVT in plain language.
When to call your physician
Anyone managing PTS should have a low threshold for calling their physician if they notice:
- New unilateral leg swelling that develops suddenly.
- New calf pain, warmth, or redness suggestive of a recurrent DVT.
- Shortness of breath or chest pain (which can suggest a pulmonary embolism and is an emergency).
- A non-healing wound on the lower leg.
- Skin breakdown around the ankle.
PTS is a chronic condition, but recurrent DVT and venous ulcers are not symptoms to wait out at home.
Putting it together
PTS is one of the most common long-term consequences of a leg DVT. It develops because the original clot leaves the venous valves and walls less able to handle pressure, and the resulting venous hypertension drives the swelling, heaviness, skin changes, and (in advanced cases) ulcers that define the syndrome. Long-term graduated compression is the most accessible tool patients have for managing those symptoms day to day. Paired with movement, elevation, skin care, and ongoing medical follow-up, daily compression turns PTS from a constant burden into something most people can live with comfortably.
Frequently asked questions
How long should I wear compression stockings after a DVT?
That is a clinical decision based on your individual case. Many patients wear them daily for two years or longer; some continue indefinitely if PTS symptoms are present. Your physician will tailor the plan.
Do compression stockings prevent another DVT?
Compression is part of comprehensive prevention, especially during high-risk activities like long flights. The primary protection against recurrent DVT is staying on prescribed anticoagulation as directed and addressing personal risk factors.
Is 30-40 mmHg always better than 20-30 mmHg for PTS?
No. Higher pressure is appropriate for more severe disease but is harder to don, less comfortable, and not safe for everyone. Many patients do well at 20-30 mmHg with good adherence.
Will compression undo the damage from my DVT?
No. Compression manages symptoms and reduces ongoing pressure load. It does not rebuild damaged valves or remove residual venous obstruction.
Should I take my stockings off at night?
Generally yes, unless a clinician specifically advises otherwise. Venous pressure drops when you are horizontal, so overnight compression is rarely necessary.
Related reading
- How compression socks help prevent deep vein thrombosis
- Are compression socks good for DVT?
- Managing edema with compression socks
Information in this article is intended for general education. It is not a substitute for medical advice. If you have had a DVT or suspect PTS, work with your physician or a vascular specialist on a personalized plan.
