Venous Insufficiency

Etiology

Chronic Venous Insufficiency is an advanced stage of venous disease in which veins can no longer permit normal antegrade blood flow.  Veins are said to be "incompetent", and characterized by faulty or damaged valves, allowing blood to flow in both directions.  Retrograde or backward flow allows blood to pool or become stagnate.  This generally occurs in the lower extremities, where gravity favors the pooling of blood caudally.

Normally, ambulation and the pumping action of the calf muscles propels venous blood upward towards the heart, through a series of valves which prevent retrograde flow.  During and immediately following ambulation, the pressure in the venous system is close to zero.  Arterial inflow fills the veins slowly and the only source of venous pressure comes from the hydrostatic pressure from the column of blood as high as the next valve.  Damaged valves allow the pressure of the column of standing blood in the vein to remain high, even during ambulation.  The hydrostatic pressure increases during and immediately after ambulation.  It is this increased venous pressure which is responsible for many of the sequelae of venous insufficiency.

So what would cause venous valves to become incompetent?  In the deep venous system, valves can become damaged as a result of deep venous thrombosis (DVT), however, most venous insufficiency is a result of incompetence in the superficial system.  Superficial venous valves can fail for a number of reasons including direct injury, a superficial phlebitis, congenitally weak veins, and distensibility under the influence of hormones (i.e. pregnancy).

Most instances of superficial venous valve failure occur, however, after a single point of high-pressure leakage develops between the deep and superficial systems.  The high pressure causes secondary failure when otherwise normal veins become so distended that their valve flaps can no longer make contact to close within the vessel lumen.  This leads to a common condition known as varicose veins.

Clinical Presentation

Patients with venous insufficiency often complain of symptoms in the early and late courses of the disease, with some sparing in the middle.  Burning, swelling, throbbing, cramping, and aching are not uncommon complaints.  Patients with insufficiency in the deep system often complain of leg aching, heaviness, and soreness (restless legs).  Clinical manifestations of chronic venous insufficiency include swollen legs (edema), hyperpigmentation, and venous stasis ulcers or dermatitis (see pictures).

Edema may be the result of DVT or deep/superficial reflux.  Additionally, swelling could be completely unrelated to the venous system (i.e. CHF, lymphatic edema).  Skin discoloration may be a sign of venous stasis, or arterial insufficiency.  Non-healing ulcers may also be due to either deep or superficial insufficiency.  Blood which pools in an already congested extremity is oxygen-poor and lactate-rich, making the healing of ulcers extremely difficult. 

Discolored skin and ulcers caused by venous stasis tend to occur on the medial aspect of the ankle or lower leg.  This is largely in part due to the fact that these areas are especially prone to venous hypertension, as their drainage largely depends on the competence and patency of the entire length of the greater saphenous vein and its tributaries.

Skin changes or ulcerations on the lateral aspect of the leg are typically due to prior trauma or arterial insufficiency.

Diagnosis is made with a careful history and physical exam (as above).  Duplex ultrasonography is the study of choice for venous insufficiency syndromes, as it is both sensitive and specific.  If the duplex scan is not diagnostic, venography may be necessary.

Treatment

The initial, conservative approach to treating venous insufficiency is elevation of the extremity and the use of graduated compression stockings.  Graduated stockings provide increased compression at the ankle (30-50mmHg) with decreasing compression proximally.  This is usually sufficient to restore normal venous flow patterns in most patients with superficial disease and some with deeper disease.  The graduation component is important as non-graduated stockings can cause a tourniquet effect, with worsening of the insufficiency. 

Patients with ulcerations require meticulous wound care in order to prevent infection while healing, and occasionally a Unna Boot (a tight, medicated dressing) is required.  Antibiotics are rarely useful for venous ulcerations.

The goal of surgical care is to improve venous circulation, by removing the reflux pathways themselves.  No real treatment for deep venous disease has been shown to be safe and/or effective, but superficial disease is easily ablated.  As is the case for the treatment of varicose veins, the surgical treatment of venous insufficiency includes simple ligation and division of veins, vein stripping, stab avulsion, and sclerotherapy (see Treatment of Varicose Veins for more information).