What chronic venous insufficiency is
Chronic venous insufficiency is a condition where the valves inside the leg veins fail, allowing blood to pool downwards under gravity instead of returning efficiently to the heart.
The leg veins have one job: to carry blood back up to the heart, against gravity. They do this with the help of small one-way valves spaced along the length of each vein. When you contract your calf muscles, blood is pushed upward; the valves close behind it to stop it flowing back down.
In CVI, those valves stop working properly. Blood pools in the lower leg, pressure builds up in the veins and tiny skin vessels, and fluid leaks into the surrounding tissues. Over time the skin changes, the leg swells, and in severe cases ulcers can form.
CVI is usually a chronic mechanical problem. The damaged valves do not usually repair themselves, but symptoms can improve substantially with compression, exercise, weight loss, elevation, and treatment of reflux when appropriate. Most people who are recognised and treated early can reduce symptoms and lower the risk of progression to skin damage or ulceration.
Symptoms and signs
CVI tends to start subtly. By the time someone seeks help, they often have several symptoms that have crept in over months or years.
Common symptoms:
- Heaviness, aching, or tiredness in the legs, especially by the end of the day
- Swelling around the ankles that improves overnight and worsens with standing
- Visible varicose veins or spider veins
- Skin discolouration — brown or rusty staining around the inner ankle
- Itching, eczema, or dryness over the lower leg
- Some people also report restless legs or night cramps, although these symptoms can have other causes
- In advanced disease: thickened, woody skin around the ankle (lipodermatosclerosis) or a non-healing wound (venous ulcer)
CVI symptoms typically improve with elevation and worsen with prolonged standing or sitting. That pattern — worse with gravity, better with rest and elevation — is a useful clinical clue.
Stages of CVI (CEAP simplified)
Doctors classify CVI using the CEAP system. For patients, the easiest version is the clinical part — a 7-stage scale (C0 to C6) describing how far the disease has progressed.
| Stage | What it looks like | What it means |
|---|---|---|
| C0 | No visible signs | Symptoms only — heaviness, aching |
| C1 | Spider veins or small reticular veins | Earliest visible venous disease |
| C2 | Varicose veins larger than 3 mm | Established superficial venous reflux |
| C3 | Ankle or leg swelling | Venous hypertension reaching the tissues |
| C4 | Skin changes — brown discolouration, eczema, hardening (lipodermatosclerosis) | Time to act — skin breakdown is the next stage |
| C5 | Healed venous ulcer | Skin has recovered but the underlying CVI remains |
| C6 | Active venous ulcer | Severe disease — needs specialist wound care |
The point of the staging system is that treatment becomes more important — and more time-sensitive — as the stage advances. Compression therapy and intervention at C3 or C4 can prevent the leg ever reaching C6.
Risk factors
Some risk factors for CVI are within your control; others are not.
Risk factors that increase your chance of CVI:
- Age — risk rises steadily with each decade
- Female sex — women are affected more often than men
- Family history of varicose veins or CVI
- Pregnancy (especially multiple pregnancies)
- Prolonged standing or sitting at work
- Obesity
- Previous deep vein thrombosis (DVT) — the main cause of severe, one-sided CVI
- Oestrogen-containing contraception or HRT — these mainly increase the risk of venous thrombosis in susceptible people, which can then lead to post-thrombotic venous insufficiency
A previous DVT is one of the most important medical risk factors. A significant proportion of people develop post-thrombotic symptoms afterwards, ranging from mild chronic swelling through to severe skin changes and ulceration — the most severe form of CVI.
Varicose veins — the visible side of CVI
Varicose veins and CVI often share the same underlying mechanism: venous reflux from failing valves. Varicose veins may be the visible early sign of that process, while CVI describes the broader clinical syndrome of venous hypertension, swelling and skin change.
Not everyone with varicose veins has symptomatic CVI, and not everyone with CVI has visible varicose veins (you can have valve failure in the deep veins, which you cannot see from the outside). But when both are present, the underlying pathology is shared: incompetent valves allowing reflux of blood under gravity.
Implications:
- Visible varicose veins are a sign that the venous system is not working normally — even if there are no other symptoms yet
- Fine spider veins alone are often cosmetic, but if they occur with aching, swelling, varicose veins or skin change, duplex ultrasound may be appropriate
- Larger varicose veins (>3 mm, ropey, bulging) are more often associated with significant reflux
- A venous duplex ultrasound determines whether varicose veins are a cosmetic finding or the visible sign of a treatable mechanical problem
Treatment for varicose veins (endovenous ablation, sclerotherapy) addresses the same underlying reflux as CVI treatment. See the treatment section below.
How CVI is diagnosed
CVI is often suspected from the history and examination. Venous duplex ultrasound is the key investigation that confirms reflux, identifies the affected veins, and guides treatment.
Venous duplex ultrasound
The key investigation- What it is
- A non-invasive ultrasound scan of the leg veins. Specifically looks for reflux — backward flow of blood when normal forward flow should be happening.
- What it identifies
- Which veins are affected (superficial — great saphenous, small saphenous; deep; or perforator), and distinguishes primary CVI from post-thrombotic syndrome.
- Why it matters
- Determines whether you are a candidate for procedural treatment, and which procedure is appropriate.
Other tests sometimes used:
- Blood tests are not used to diagnose CVI itself, but may be ordered to exclude other causes of leg swelling
- Echocardiogram and BNP/NT-proBNP — when heart failure is also a possibility (see section 8)
- Kidney function, liver function, urine protein, thyroid function and albumin may be checked when the pattern suggests a systemic cause of swelling
Treatment — what actually works
CVI treatment follows a clear hierarchy. Most people get most of their benefit from the first three steps, before any procedure is considered.
First line — for everyone with CVI
- Compression therapy — compression stockings, 20-30 mmHg for most; 30-40 mmHg for severe disease or healed ulcers
- Leg elevation above heart level, several times daily where possible
- Calf-pump exercise — walking, ankle pumps, dorsiflexion
- Weight management
- Skin care to prevent and treat venous eczema and lipodermatosclerosis
When first-line treatment is insufficient — referral to a vascular specialist
If reflux is confirmed on duplex ultrasound and symptoms persist despite conservative treatment, a vascular specialist may discuss procedural options such as:
- Endovenous ablation — radiofrequency (RFA) or laser (EVLA). The current standard for treating the great or small saphenous vein. It is usually performed under local anaesthetic, and most patients walk out the same day.
- VenaSeal — medical adhesive technique
- MOCA — mechanochemical ablation
- Foam sclerotherapy — for smaller tributary veins
- Phlebectomy — surgical removal of large bulging veins, usually combined with ablation
- Open surgical stripping — now rarely indicated; ablation has replaced it
When CVI looks like heart failure (and when both coexist)
As a cardiologist, I often see patients whose leg swelling has been attributed to the heart, when the main problem is actually venous reflux — and the reverse also happens. The important step is not guessing from appearance alone, but matching the pattern of swelling with the right investigations.
The clinical mistake is not simply confusing one diagnosis for the other. The bigger mistake is assuming that only one diagnosis is present. A patient can have venous reflux causing ankle swelling and HFpEF causing exertional breathlessness at the same time.
CVI and heart failure both cause bilateral pitting leg oedema. The distinction matters because the treatments are very different.
| Feature | CVI | Heart failure |
|---|---|---|
| Onset | Gradual, years | Can be acute, subacute or chronic; often worsens over weeks to months |
| Time of day | Worse end of day, better overnight | Often present all day |
| Trigger | Standing, sitting, heat | Exertion, lying flat (orthopnoea) |
| Breathlessness | Not usually | Common — on exertion or lying flat |
| JVP | Normal | Often raised |
| Skin changes | Brown ankle staining, varicose veins | Smooth, sometimes weepy in acute decompensation |
| Investigation | Venous duplex ultrasound | BNP/NT-proBNP, echocardiogram |
| First-line treatment | Compression, elevation, ablation | Heart failure medications, diuretics |
When they coexist
Many older patients have both — long-standing CVI and new-onset HFpEF, for example. Two pitfalls to avoid:
- Treating leg swelling with diuretics alone — gets rid of fluid temporarily but misses the venous problem, leaving the patient on lifelong diuretics for a mechanical problem.
- Treating with compression alone when heart failure is the dominant problem — the leg looks better but the breathlessness keeps progressing.
The right approach is to recognise both, treat both, and have the cardiology and venous treatment plans complement each other.
When to see a specialist
| Situation | Where to start |
|---|---|
| Heaviness, aching, mild swelling, no skin changes | GP first; can start compression and lifestyle measures |
| Visible varicose veins, cosmetic concern or symptoms | GP first, then vascular specialist for duplex US and consideration of ablation |
| Skin changes, hyperpigmentation, lipodermatosclerosis | Vascular specialist — important to intervene before ulceration |
| Active venous ulcer | Vascular specialist + wound care team — urgent |
| Bilateral swelling with breathlessness, raised JVP, or known heart disease | Cardiologist; CVI may also be present |
| Non-pitting swelling, foot/toe involvement, or long-standing asymmetry | Consider lipoedema or lymphoedema assessment |
| Sudden one-leg swelling | Exclude DVT first — emergency assessment |
The cardiologist's role. A cardiologist does not usually perform venous ablation, but is often involved when leg swelling may be cardiac, when breathlessness is present, or when CVI and heart failure appear to coexist. The role is to distinguish cardiac from venous oedema, assess for heart failure with echo and BNP/NT-proBNP, and coordinate care with vascular specialists when venous intervention is required.
Frequently asked questions
Are compression stockings forever?
Many people with established CVI use compression long term, but the intensity and frequency may change after successful treatment of reflux. After endovenous ablation, daily compression often becomes optional, though most specialists recommend continued use during long flights, prolonged standing, or hot weather.
Will compression stockings get rid of my varicose veins?
No. Compression manages symptoms and slows progression but does not reverse the underlying valve damage or remove existing varicose veins. Procedural treatment is needed for that.
Will CVI cause shortness of breath?
CVI itself does not cause breathlessness. If you have leg swelling and breathlessness together, the swelling is likely cardiac, the breathlessness is likely cardiac, or both. A cardiology assessment is appropriate.
Can I fly with CVI?
Yes. Wear graduated compression stockings during the flight, stay well hydrated, and walk every hour or two if possible. People with a previous DVT, active cancer, recent surgery, known thrombophilia, or very high clot risk should discuss individual travel precautions with their doctor before long-haul flights.
Is CVI dangerous?
Untreated severe CVI causes skin breakdown, chronic ulcers, recurrent cellulitis, and significantly reduced quality of life. It is not directly life-threatening, but the morbidity is serious — and largely preventable with treatment.
Do I need surgery for CVI?
Most people with CVI do not need surgery. First-line treatment is compression, elevation, and lifestyle changes. When procedural treatment is needed, most modern options are minimally invasive procedures (endovenous ablation, sclerotherapy, VenaSeal) rather than open surgery, performed under local anaesthetic with same-day discharge.
Is endovenous ablation painful?
It is done under local anaesthetic with a fine catheter through a small puncture in the lower leg. Most patients describe minor discomfort during the tumescent anaesthetic injection and tightness for a few days after; no general anaesthetic, no overnight stay, walking out of the clinic the same day.
Does losing weight help CVI?
Yes — meaningfully. Obesity raises venous pressure and worsens valve incompetence; weight loss reduces venous symptoms and may slow progression. It is not a cure for established valve damage, but it is one of the strongest modifiable risk factors.
References & further reading
Clinical references
- De Maeseneer MG, et al. Editor's Choice — European Society for Vascular Surgery (ESVS) 2022 Clinical Practice Guidelines on the Management of Chronic Venous Disease of the Lower Limbs. Eur J Vasc Endovasc Surg. 2022;63(2):184-267.
- Gloviczki P, et al. The 2022 Society for Vascular Surgery, American Venous Forum, and American Vein and Lymphatic Society clinical practice guidelines for the management of varicose veins of the lower extremities. J Vasc Surg Venous Lymphat Disord. 2023;11(2):231-261.
- Lurie F, et al. The 2020 update of the CEAP classification system and reporting standards. J Vasc Surg Venous Lymphat Disord. 2020;8(3):342-352.
- Heidenreich PA, et al. 2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure. J Am Coll Cardiol. 2022;79(17):e263-e421.
- Therapeutic Guidelines (Australia, eTG complete) — Chronic venous insufficiency; Varicose veins.
Further reading on this site
- Leg swelling (lower limb oedema): causes, when to worry, and what to do (pillar)
- Unilateral leg swelling: differential diagnosis and case studies
- Lipoedema: diagnosis and management
- Lymphoedema: causes, diagnosis and treatment (coming soon)
- Echocardiogram at Westmead
