Reference Article
CHRONIC VENOUS ULCER
A narrative clinical review: Etiology; Evaluation; Treatment..
Some interesting points:
Ulceration is part of the complex of chronic venous insufficiency. It is associated with distal vein hypertension. Both primary valvular incompetence and venous thrombosis can cause the ulceration. "It is clear that a venous ulcer of the leg occurs mainly from reflux and not usually from persistence of the original obstructive process."
Primary venous insufficiency occurs when no obvious cause of valvular dysfunction is identified. Secondary venous insufficiency occurs when there is an identifiable cause such as previous deep venous thrombosis. Whatever the cause, gravitational reflux from valvular dysfunction results in early refilling of the venous pool in the leg after muscle contraction. This leads to capillary dilation and leakage of plasma, plasma proteins and blood cells. Ulceration is thought to result from the distal adherence, trapping, and activation of leukocytes causing tissue destruction. In addition, blockage of capillary blood flow occurs due to thrombosis from platelet activation and adherence of neutrophiles. In advanced chronic venous stasis, superficial reflux (incompetence) may be the only finding; in others perforating vein incompetence is also present.
When perforating veins are incompetent the high pressures developed in calf muscles during contraction exposes the superficial veins to high pressure. Chronic exposure of the superficial system to high pulsatile pressures dilates and elongates the superficial veins. (This has been termed the hydraulic ram.)
Benefit of graded elastic compression stockings has been generally accepted. The beneficial effects are probably due to local alteration of microvascular hemodynamics and regional Starling forces, relieving edema, rather than any direct effect on deep vein hemodynamics. Thus stockings do not cure venous hypertension but do protect the skin from its effects.
Severe forms of edema require non-elastic compression. The most commonly used device is the Unna cell paste gauze boot which is designed to provide both compression and topical treatment.
Surgical correction of superficial vein insufficiency or perforating vein outflow should be done early. Incompetent perforating veins should be suspected in every case.
The normal flow is from the superficial veins to the deep veins through the perforating veins. If the perforating veins become incompetent the flow is reversed. Effective treatment of chronic venous insufficiency requires control of the perforating veins. Endoscopic surgical techniques have made interruption of perforating veins less morbid— extensive incisions are eliminated, and healing of the leg ulcer is accelerated without creating a major problem of infection.
BMJ April 5, 1997; 314: 1019-23 Narrative clinical review from Univ. of California, San Diego

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