varicose veins

varicose veins A varix or varicosity is an irregularity or lumpiness. In the body, this means irregularities caused by dilated and distorted veins.

Veins in the legs have valves which normally prevent any backflow of the blood on its way towards the heart. The pressure of the blood tending to distend these veins is greater than in veins elsewhere simply because, for most of most people's waking hours, they are lower than the rest of the body, and vertical. This can put a considerable strain on the valves, each of which supports the column of blood immediately above it, between it and the next valve further up. In ideal normal circumstances the blood is kept moving upwards effectively because of persistent squeezing of veins by actively contracting muscles as we walk about, as well as by other mechanisms which tend continually to draw the blood towards the chest. The superficial veins just under the skin benefit less directly than the deep ones from leg movements — but because they connect to the deep veins, squeezing by the muscles helps to siphon blood from those near the surface, as well as ‘milking’ it up the deep ones.

Thus gravity does not normally cause an accumulation of weighty blood in our lowest parts, as it would in, say, a liquid-filled bicycle inner tube suspended vertically. But there are less than ideal circumstances which cause relative stagnation, particularly in the superficial unsupported veins; blood then leans more heavily on the valves, and in some cases these become damaged and develop leaks. This can occur if there is an obstruction to blood flow up from the legs (such as a heavily pregnant uterus pressing on the veins in the pelvic cavity) and the problem is exacerbated by sitting or standing still. As for many bodily dysfunctions, there is no doubt a combination of innate propensity (weak veins and valves) and risk factors (flow obstruction and immobility). The leakage of valves in turn leads to the irregular bulges on the veins which are known as varicosities, along with enlargement and distortion. The sluggishness imposed on the circulation to the skin and underlying tissues by back pressure from these veins predisposes to discomfort, ulceration, and oedema.

Applying pressure by support stockings to keep the varicose veins from filling is the first line of treatment. But the veins which are affected are fortunately usually dispensible: if they are removed, blood can flow through alternative deeper channels. Effective surgical treatment involves making cuts only at the top and the bottom of the offending vein, which is then removed by using a ‘stripper’. From the top end (say at the knee) a thin flexible rod is passed down the vein to the far end (say at the ankle). The vein is tied around the rod, which has a knob on its end. Pulling from the top then causes the knob to draw the whole length of the vein up before it, ‘crumpling’ it as it comes. Thus the vein is pulled by the stripper from under the skin and out through the upper incision.

A similar problem can occur at other sites. In the lower end of the oesophagus, ‘varices’ may result from back pressure associated with liver disease. In the scrotum a ‘varicocoele’ is a swelling of the veins around the testis. Haemorrhoids represent a comparable condition of the anal veins.

Sheila Jennett

See also blood circulation; blood vessels.