What Causes Chronic Venous Insufficiency?
Medically verified
Last updated on 1/29/2026
By Dr. Michael Nguyen
Vein Doctor at Vein Treatment Clinic
Harvard Medical School
Board Certified by the American Board of Venous and Lymphatic Medicine
Chronic venous insufficiency develops when the veins in the legs stop working properly and can no longer move blood efficiently back toward the heart. This results in poor circulation in the leg veins and increased pressure inside the vessels.
In most cases, this happens because the one-way valves inside the veins fail. When these valves weaken or do not close completely, blood flows backward, a condition known as venous reflux, which is one of the primary causes of chronic venous insufficiency.
Understanding what causes chronic venous insufficiency, and what causes venous insufficiency to progress, helps patients recognize risk factors and why symptoms often worsen over time without treatment.
If you’re experiencing leg symptoms and want to understand what may be causing them, a vein evaluation can help clarify the underlying issue.
Failure of vein valves
The most common cause of venous insufficiency is failure of the one-way valves inside the leg veins.
When these valves do not close properly, blood flows backward and pools in the legs, increasing vein pressure.
When vein valves fail, circulation in the legs becomes inefficient, which explains why many patients describe their symptoms as poor circulation in the lower legs.
Venous reflux and backward blood flow
Venous reflux refers to blood flowing in the wrong direction due to valve failure.
Over time, reflux increases pressure in the veins and damages vein walls and surrounding tissue.
Genetics and inherited vein weakness
Genetics plays a significant role in chronic venous insufficiency.
People with a family history of vein disease are more likely to develop valve dysfunction and CVI.
Symptom Checker
History of blood clots or vein injury
Prior blood clots, especially deep vein thrombosis, can damage vein valves.
This damage can permanently disrupt blood flow and lead to chronic venous insufficiency.
Aging and loss of vein elasticity
As people age, veins naturally lose elasticity and strength.
Weaker vein walls and valves are more likely to fail over time, increasing the risk of CVI.
Prolonged standing or sitting
Long periods of standing or sitting reduce the muscle pumping action that helps move blood out of the legs.
This increases pressure in the veins and accelerates valve damage.
Does This Sound Like You? Check Your Symptoms
Table of contents
1. Failure of vein valves
2. Venous reflux and backward blood flow
3. Genetics and inherited vein weakness
4. History of blood clots or vein injury
5. Aging and loss of vein elasticity
6. Prolonged standing or sitting
7. Pregnancy and hormonal influences
8. Excess weight and increased vein pressure
9. Varicose veins as a contributing factor
10. Why chronic venous insufficiency often worsen over time?
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Pregnancy and hormonal influences
Pregnancy increases blood volume and pressure in the leg veins while hormones relax vein walls.
These changes can contribute to valve failure and long-term vein problems.
Temporary Change or Lasting Issue? Learn How Pregnancy Affects Your Vein Health
Excess weight and increased vein pressure
Extra body weight increases pressure on the leg veins.
While weight alone does not cause CVI, it can worsen existing vein disease.
Varicose veins as a contributing factor
Varicose veins are often an early sign of chronic venous insufficiency.
As varicose veins worsen, they can contribute to increasing venous pressure and CVI progression.
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Why chronic venous insufficiency often worsens over time?
Valve damage does not repair itself, which is why chronic venous insufficiency tends to progress.
Without treatment, increasing pressure can lead to swelling, skin changes, and ulcers.
< What Is Chronic Venous Insufficiency?
How Does Chronic Venous Insufficiency Affect Circulation? >
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