Dysfunction of the venous system can be mainly primary in almost 90% of cases) or secondary (approximately 10% of cases of chronic venous disease). Sooner or later, it leads to progressive chronic venous disease (CVD), which affect up to 30% of the population in industrialised countries, with a clear predominance among women (2 women for every one man, all ages combined).
By Jean-Patrick Benigni, MD, General Secretary of the French Society of Phlebology, Paris – France
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The term Primary Chronic Venous Disease (CVD) covers all chronic symptoms and clinical signs related to damage to the valves or the venous wall with no identified cause.
Various epidemiological studies have led to identification of risk factors for primary chronic venous disease. Some risk factors are indisputable, while others are more hypothetical.
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Indisputable factors
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Age:
Chronic venous disease becomes more frequent with age, especially over the age of 60.
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Hereditary factors:
50% of patients with varicose veins have at least one parent with varicose veins. If both parents suffer from varicose veins, 90% of their children have the condition.
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Gender:
Women more often present symptoms of the disease than men.
Pregnancies promote the development of varicose veins and the number of full-term pregnancies is recognised as a major risk factor in the onset of the condition.
- Contraception and hormone treatments containing oestrogens or certain progestogens are undeniably a factor involved in the progression of the disease.
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sedentary lifestyle:
The incidence of varicose veins is significantly higher in women who spend more than eight hours per day in the same position than in more active women. A detrimental effect of a lack of physical activity is also observed in men.
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Obesity and overweight:
Varicose veins are said to be more common in obese people. This notion is sometimes disputed. But there is no doubt that morbid obesity promotes the development of trophic changes, even in the absence of venous reflux.
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Position at work:
Working standing up for more than six hours per day leads to an increased incidence of varicose veins in both women and men.
Hypothetical factors
The following have been accused of playing a role in the development of venous disease:
- high-impact sports (tennis, football, etc.),
- heat,
- tight clothing,
- sitting with legs crossed
- constipation,
- diet, etc.
As yet, no scientific evidence has corroborated the role of these factors.
The Laboratoires URGO thank a lot Dr Benigni for its collaborative work on this website.
By Jean-Patrick Benigni, MD, General Secretary of the French Society of Phlebology, Paris – France
Deep vein thrombosis leads to blocking of the deep venous network.
In the short term, venous blood flow is then diverted to the superficial network, hence a dilation of the superficial veins and swelling of the limb in certain cases.
Either following treatment or spontaneously, a portion of the obstructed vein will unblock. This destruction of the clot also causes destruction of the deep valves involved.
In the medium term, the absence of continent valves causes hypertension (excessive pressure) in these veins since the blood column is no longer “retained” by the valves. The weight of the blood column is then borne by the lowest vein. Since the blood no longer returns towards the heart, there will therefore be blood reflux towards the lowest peripheral vein.
At the lowest point of the “unblocked” vein, the pressure will therefore be too high.
This hypertension will then be passed on to the superficial network. The previously functioning superficial network will deteriorate under the effect of this excessive overload, leading to dilation of the superficial veins and valve incompetence in these superficial veins.
Following phlebitis, the venous blood therefore flows from the “unblocked” deep veins towards the superficial veins, via perforating veins passing through sheaths surrounding the muscles (aponeuroses).
In the absence of appropriate management, the signs of CVD will gradually become established.
It should be noted that a thrombosis can have two possible courses:
- the clot or thrombus may dissolve within a greater or lesser period of time,
- or the affected vein may remain blocked.
In the first case, if the vein has lost a lot of valves when the clot dissolved, hypertension will rapidly develop in the vein. The limb will swell and varicose veins will subsequently appear.
In the second case, if the obstruction affects a large vein, the leg will also swell since the blocked vein will act as an obstacle preventing venous return. Varicose veins will also develop subsequently if the vein does not unblock. This second situation is less common nowadays due to the availability of effective anticoagulant treatments.
Rarely, the CVD can have a congenital origin (absence of valves or incompetent valves)
Theoretically, therefore, we should not talk about chronic venous disease but about chronic venous disorders, in the plural.
