Introduction
This topic covers chronic venous insufficiency, with varicose veins as its most common form. You should be able to explain how valve failure leads to venous hypertension, list the main causes and risk factors, describe the clinical picture by stage, and name the complications and how they are recognised.
Definition and pathophysiology
Chronic venous insufficiency is a long-term disorder of the venous system of the legs in which the veins cannot return blood efficiently to the heart. Varicose veins are dilated, elongated and tortuous superficial veins, most often the great saphenous vein and its tributaries.
The key mechanism is valve incompetence:
- Normally the venous valves prevent retrograde flow, and the calf muscle pump moves blood upward.
- When valves fail, blood refluxes downward during standing, especially after muscle contraction ends.
- Reflux raises ambulatory venous pressure. Through incompetent perforating veins, this pressure is transmitted into the superficial system, which dilates and loses its valves further.
- Chronic venous hypertension causes capillary damage, leakage of fibrin and red cells, and local inflammation, which underlie the skin changes described below.