Post-Thrombotic Syndrome (PTS)

What happens in post-thrombotic syndrome

After a deep vein thrombosis, the body breaks down and scars the clot. In the process:

• the one-way valves in the veins can be damaged, so blood flows backward (reflux)
• the vein may stay partly blocked (obstruction)

Both raise pressure in the leg veins (venous hypertension) whenever you stand or walk. Over time, high pressure causes fluid leakage, inflammation, skin damage and ulcers.

Symptoms

Symptoms typically worsen through the day and with standing or walking, and improve with rest and elevation:

• aching, heaviness or tiredness of the leg
• swelling of the lower leg and ankle
• cramps
• itching or tingling
• pain on walking that eases with rest and elevation (venous claudication), especially after large pelvic clots

Signs

• swelling (edema)
• new varicose veins or small surface veins around the ankle
• reddish-brown skin discoloration
• eczema-like changes (stasis dermatitis)
• hardened, tight skin above the ankle (lipodermatosclerosis)
• venous ulcers, usually on the inner ankle

Risk factors

• DVT in the thigh or pelvis (iliofemoral DVT), which carries the highest risk
• recurrent DVT in the same leg
• persistent symptoms 1 month after DVT
• obesity
• older age
• pre-existing venous insufficiency
• poorly controlled anticoagulation in the first months, such as warfarin outside target range

Diagnosis

PTS is diagnosed clinically, usually at least 3 to 6 months after the DVT, once acute swelling and pain have settled. Doctors use scoring tools such as the Villalta scale, which rates symptoms and signs. Tests include:

• duplex ultrasound: checks for reflux, blocked veins and new clots
• CT or MR venography: for suspected iliac vein obstruction
• tests to exclude other causes of swelling, such as heart, kidney or lymphatic problems

Prevention

The best prevention is preventing DVT in the first place and treating it well:

• effective anticoagulation for the recommended duration
• early walking after DVT, as soon as pain allows, rather than bed rest
• staying active and maintaining a healthy weight
• compression stockings: recent trials did not show that routine compression prevents PTS for everyone, so they are now recommended mainly to relieve symptoms
• clot removal procedures (catheter-directed thrombolysis or thrombectomy) may be considered for selected patients with extensive iliofemoral DVT and low bleeding risk

Treatment

Conservative care

• graduated compression stockings (often 20 to 30 or 30 to 40 mm Hg) to reduce swelling and aching
• leg elevation above heart level several times a day
• exercise: walking and calf-strengthening exercises improve the calf muscle pump
• weight loss if overweight
• skin care: moisturize daily, treat eczema with topical treatments, and protect the skin from injury
• intermittent pneumatic compression devices for severe swelling

Ulcer care

• compression bandaging, which is the cornerstone of healing venous ulcers
• wound dressings and treatment of infection
• treating superficial vein reflux to reduce recurrence

Procedures

For severe PTS with blocked iliac veins, venous stenting can relieve symptoms. Surgery or ablation of incompetent superficial veins may help some patients. Valve repair is rarely performed.

Outlook

PTS is long-term and often lifelong, but most people have mild to moderate symptoms that can be managed with exercise, compression and skin care. Severe PTS with ulcers affects a minority and needs specialist care.

Frequently asked questions

What is post-thrombotic syndrome?

Post-thrombotic syndrome is a long-term condition that develops after a deep vein thrombosis. Damaged vein valves or blocked veins cause blood to pool in the leg, leading to aching, heaviness, swelling, skin discoloration and sometimes leg ulcers.

How common is post-thrombotic syndrome after a DVT?

It develops in about 20% to 50% of people after a leg DVT, usually within 1 to 2 years. Severe forms with leg ulcers affect a smaller proportion, around 5% to 10%. The risk is highest after large clots in the thigh or pelvis.

Do compression stockings prevent post-thrombotic syndrome?

Large studies have shown that routine compression stockings do not prevent PTS for everyone. They are still useful for relieving swelling and aching in people with symptoms. Your doctor can advise on the right type and pressure.

What are the symptoms of post-thrombotic syndrome?

Typical symptoms are leg heaviness, aching, swelling, cramps and itching that worsen after standing and improve with rest and elevation. Signs include varicose veins, brown skin discoloration, hardened skin and, in severe cases, ulcers near the ankle.

Can post-thrombotic syndrome be cured?

There is usually no cure, because vein damage is permanent, but symptoms can be well controlled. Exercise, compression, leg elevation, weight control and skin care help most people. Stenting or vein procedures can help selected people with severe symptoms.