ConditionHeart & circulation
Venous Stasis
Venous stasis means blood flows too slowly in the veins, usually of the legs, and pools there instead of returning to the heart. Short-term stasis from sitting still on long flights, bed rest or surgery raises the risk of blood clots (deep vein thrombosis). Long-term stasis from damaged vein valves causes venous stasis disease: swollen ankles, aching legs, brown skin discoloration, itchy rash and eventually leg ulcers. Moving your calves, compression stockings and leg elevation are the core treatments.
Also called: Venous stasis disease, chronic venous stasis, poor venous return, venous pooling
At a glance
- What it is
- Sluggish blood flow in the veins, with pooling in the lower legs.
- Short-term causes
- Immobility (flights, car trips, bed rest, casts), surgery, and paralysis.
- Long-term cause
- Chronic venous insufficiency from failed vein valves or past clots.
- Signs of chronic stasis
- Ankle swelling, heavy legs, brown staining, itchy scaly skin, hardened skin, ulcers near the ankle.
- Treatment
- Walking and calf exercises, compression, elevation, skin care, and procedures for faulty veins.
When to get help
Call 911 or go to the ER
- Sudden shortness of breath, chest pain or coughing blood, especially after a long trip, surgery or bed rest (possible pulmonary embolism)
See a doctor within a day or two
- One leg suddenly swollen, painful, warm or red, particularly in the calf (possible deep vein thrombosis)
- Spreading redness, heat and pain in the lower leg with fever above 100.4°F (38°C) (possible cellulitis)
- A painful, hard, red cord along a vein
Book a routine appointment
- Ankle swelling that is worse in the evening and better in the morning
- Brown discoloration, itchy rash or hardening of the skin around the ankles
- A sore near the ankle that has not healed in 2 weeks
Usually safe to manage at home
- Mild evening ankle swelling with known vein problems: walk regularly, raise your legs above heart level for 30 minutes several times a day, and wear compression stockings if advised
How venous blood normally flows
Blood returns from the legs to the heart against gravity. Two things make this possible:
- The calf muscle pump: each step squeezes the deep veins and pushes blood upward.
- One-way valves inside the veins stop blood from falling back down.
Venous stasis develops when either fails: the calf pump is not working (immobility, weakness, a stiff ankle) or the valves leak, so blood falls back and pressure in the lower-leg veins stays high.
Two kinds of venous stasis
| Short-term (acute) stasis | Long-term (chronic) venous stasis | |
|---|---|---|
| Typical causes | Long flights, bed rest, surgery, leg cast, stroke or paralysis | Leaking valves, varicose veins, previous DVT, obesity |
| Main risk | Blood clots (deep vein thrombosis) | Swelling, skin damage, ulcers |
| Timeframe | Hours to weeks | Months to years |
| Prevention | Moving, calf exercises, compression, blood thinners when indicated | Compression, exercise, weight loss, vein procedures |
Stasis and blood clots
Slow blood flow is one of three classic factors that cause clots, along with damage to the vein wall and blood that clots too easily. Stasis alone rarely causes a clot, but combined with surgery, cancer, pregnancy, estrogen-containing medicines or an inherited clotting disorder, the risk rises sharply.
Chronic venous stasis
When valves leak over years, high pressure in the lower-leg veins pushes fluid, proteins and red blood cells into the surrounding tissue. This causes inflammation and the skin changes described below. Doctors usually call this chronic venous insufficiency; see our page on chronic venous insufficiency for its stages and tests.
Symptoms and skin changes of venous stasis disease
- Swelling of the ankles and lower legs, worse at the end of the day and after standing
- Aching, heaviness, tiredness or cramps in the legs, relieved by raising them
- Itching around the ankles
- Varicose veins or clusters of small spider veins near the ankle
Skin changes develop over time:
| Change | What it looks like |
|---|---|
| Hemosiderin staining | Reddish-brown or rusty discoloration from iron in leaked red cells, usually around the inner ankle |
| Stasis dermatitis | Red or brown, itchy, scaly or weepy eczema-like rash |
| Lipodermatosclerosis | Hard, tight, sometimes painful skin; the lower leg can narrow like an upside-down champagne bottle |
| Atrophie blanche | Smooth white scarred patches with red dots |
| Venous ulcers | Shallow, irregular, often weepy open sores, usually above the inner ankle |
Who is at risk
- Age over 50
- Family history of varicose veins
- Previous deep vein thrombosis (post-thrombotic syndrome)
- Obesity
- Pregnancy, especially multiple pregnancies
- Jobs with long hours of standing or sitting
- Reduced mobility, a stiff ankle, or weak calf muscles
- Smoking and a sedentary lifestyle
How it is diagnosed
- Examination of the legs standing, looking at swelling, veins, skin changes and pulses
- Duplex ultrasound: shows blood flow direction, leaking valves and any clots. It is the main test
- Ankle-brachial index: checks arterial circulation, which must be adequate before strong compression is used
- Blood tests or other scans if swelling might come from heart, kidney, liver or thyroid disease
Swelling in both legs that pits on pressure can also come from heart failure, kidney disease, low protein or medicines such as calcium channel blockers. Lymphedema and lipedema also cause leg swelling with different patterns.
Treatment and self-care
Get the calf pump working
- Walk for at least 30 minutes most days
- When sitting for long periods, do ankle pumps (flex and point the feet) and get up every hour
- Calf-strengthening exercises such as heel raises
- Physical therapy for a stiff ankle
Compression
- Graduated compression stockings, tightest at the ankle, reduce swelling and slow skin damage. Typical strengths for chronic stasis are 20 to 30 or 30 to 40 mmHg, chosen by your clinician
- Compression bandages for ulcers, applied by a nurse
- Check circulation first if you have diabetes or artery disease
Elevation
Raise your legs above the level of your heart for about 30 minutes, three or four times a day, and prop up the foot of the bed if advised.
Skin care
- Moisturize daily with a plain, fragrance-free emollient
- Use a short course of steroid ointment for stasis dermatitis, as prescribed
- Avoid scratching and protect the skin from knocks, which can start ulcers
- Avoid many over-the-counter creams with fragrances, lanolin or topical antibiotics, as contact allergy is common in stasis skin
Procedures
When ultrasound shows leaking superficial veins, closing them with heat (endovenous laser or radiofrequency ablation), glue, foam sclerotherapy or surgery reduces pressure, helps ulcers heal and lowers recurrence.
Preventing clots
During long trips of 4 hours or more, walk the aisle, do calf exercises, stay hydrated and avoid alcohol and sleeping pills. People at higher risk may be advised compression stockings or a blood thinner. After surgery, follow your team's advice about early walking and clot prevention.
Frequently asked questions
What is venous stasis?
Venous stasis is slow or pooled blood flow in the veins, usually in the lower legs. It happens when calf muscles are not pumping, such as during long periods of sitting or bed rest, or when vein valves leak. It can lead to blood clots and, over years, swelling and skin damage.
What does venous stasis look like on the legs?
Early on it causes swollen ankles and visible veins. Over time, the skin around the ankles turns reddish-brown, becomes itchy and scaly, and may harden and tighten. In advanced cases, shallow sores called venous ulcers form above the inner ankle.
Does venous stasis cause blood clots?
It raises the risk. Slow-moving blood is more likely to clot, especially combined with surgery, injury, cancer, pregnancy, estrogen therapy or an inherited clotting disorder. That is why walking and calf exercises are encouraged after surgery and during long journeys.
Can venous stasis be reversed?
Swelling and discomfort can improve greatly with exercise, compression, elevation and treatment of faulty veins. Established skin staining and hardening usually fade only partly. Ulcers can heal, but ongoing compression is needed to stop them returning, because the underlying vein damage remains.
Sources
This guide was written from current patient and clinical guidance, including:
- Society for Vascular Surgery and American Venous Forum: Clinical practice guidelines for the management of varicose veins and chronic venous disease
- American Heart Association: Venous Thromboembolism (VTE)
- CDC: Blood clots and travel
- NHLBI: Venous Thromboembolism
- American Academy of Dermatology: Stasis dermatitis