by Ariel D. Soffer, MD, FACC and Faith Jaslow, ARNP

In the Unites States, the most common diagnosis for hospital admission is congestive heart failure, or CHF. One of the most common signs of CHF is bilateral leg swelling (edema). One of the most common circulatory disorders is venous insufficiency, which is also commonly associated with bilateral leg edema.

Unfortunately for clinicians and patients, the treatment of these two forms of leg edema are completely different and, therefore, mistaken diagnoses and treatments can be problematic to our entire health system (see Figure 1). Thankfully, the advances in clinical tools such as Doppler Ultrasonography have made diagnosis and differentiation of these disorders readily available.

• The intersection of VI (venous insufficiency) and CHF (congestive heart failure) with edema represents an important and challenging area of differentiation.
• The large areas of edema with VI alone (without any CHF) represent areas of medicine that have potentially easily curable edema and should not be mistaken for the less curable CHF which is treated completely differently.

The veins in the legs are responsible for transporting blood up to the veins of the torso, where it is then returned to the heart. The veins of the legs have valves that prevent the backward flow of blood within them. Venous insufficiency (VI) is incompetence of the veins that occurs because of dilation, or enlargement, of the veins and dysfunction of their valves. This happens, for example, in patients with varicose veins. VI leads to a backup of blood and increased pressure in the veins, thereby resulting in edema of the legs and feet. Edema of the legs also can occur with an episode of deep vein thrombosis (DVT), which is a blood clot within a vein. In this situation, the clot in the deep vein blocks the return of blood and consequently causes increased back pressure in the leg veins. It is also postulated that VI can be an independent risk factor for DVT, which can be a very dangerous condition.

VI is a problem that is most often localized to the legs, ankles, and feet. One leg may be more affected than the other (asymmetrical edema). However, often both legs are simultaneously affected, as the underlying anatomic pathology often is mimicked bilaterally. In contrast, systemic diseases that are associated with fluid retention (the most common one being congestive heart failure) almost always cause the same amount of edema in both legs and can also cause edema and swelling elsewhere in the body. The response to therapy with diuretic drugs in patients with venous insufficiency tends to be unsatisfactory. This is because the continued pooling of fluid in the lower extremities makes it difficult for the diuretics to mobilize the edema fluid. Elevation of the legs periodically during the day and the use of compression stockings may temporarily help the condition, but ultimately venous insufficiency is a mechanical problem that responds to mechanical solutions commonly performed today such as thermal or chemical energy ablation.

Common Causes of Venous Insufficiency:

There are several conditions than can cause the valves and veins to work improperly:

• Any problem that increases pressure in the veins in the legs can stretch the veins. This can damage the valves, which leads to even higher pressures and worsened vein function.
• A clot in a vein will block blood flow back through the vein, which can increase pressures, often permanently damaging the vein or valves even after the clot has dissolved.
• Leg injury or surgery can damage the veins or valves.
• Increased body weight (e.g., pregnancy, obesity) can increase pressure in the veins of the legs, and this can usually irreparably damage the veins and valves.
• The muscles in the legs play an important role in the circulation of blood, acting as a pump. Standing or sitting for prolonged periods without walking can decrease the movement of blood out of the legs and lead to increased pressures in the veins and pooling of blood

Common Causes of Congestive Heart Failure

• Coronary artery disease
• High blood pressure (hypertension)
• Cardiomyopathy (diseases of the heart muscle)
• Disorders of the heart valves

Conclusion

Edema of the legs is a very common and uncomfortable sign of underlying disease. With the advent of Doppler Ultrasonography, accurate diagnosis and appropriate treatment can be readily administered. As the common causes and treatment paradigms are very different for the two most frequent causes of edema (CHF and VI), it is very important that proper diagnoses are made. More research on this topic appears to be warranted for potential patient benefit and health system optimization.