Lower Extremity Arterial Occlusive Disease
Claudication is the medical term used to describe a patient who has pain in the legs after walking some distance that is relieved by rest. The distance walked prior to leg pain is generally quite reproducible. Limb-threatening ischemia presents as rest pain (pain in the toes while supine and relieved by dependency), non-healing ulcers, or gangrene. Narrowing or occlusions in the arteries that supply blood and nutrients to the legs and feet can cause all symptoms. To determine if there is a vascular cause to explain these complaints, a non-invasive lower extremity Doppler study is performed. This study measures blood pressures throughout the leg, which when compared to the arm blood pressure, gives the doctor a quantitative measurement of the lack of blood supply to the legs (Figure 1). Patients with claudication may experience a decrease in blood pressure only after exercise on a treadmill. Other parameters are also measured which provide clues as to the location of vessel narrowing and its impact.
The severity of your symptoms and the presence of disease suggested by the Doppler study determine treatment. Mild to moderate claudication can be quite successfully managed by exercise, with or without the addition of one the medications proven to be effective (Trental or Pletal) in its amelioration. If your claudication is sufficiently severe, or if limb-threatening ischemia is present, the next step is generally an angiogram. An angiogram consists of puncturing an artery with a needle and then placing a catheter in the vessel. The injection of contrast material (dye) through this catheter and taking radiologic images provides a picture of the lower body artery anatomy (Figure 2). In select cases, this roadmap can be obtained by one of two new methods, magnetic resonance imaging or computerized tomography angiography, which do not require an artery puncture. The location and extent of the involved diseased artery has some impact on how the doctor will manage the offending lesion.
If sufficiently short in length, narrowings in the aorta, iliac, or femoral arteries can be managed by percutaneous balloon dilation or stent placement. More advanced disease is best managed by a surgical bypass of the diseased vessels. Severe aortic or bilateral iliac disease requires an aortobifemoral bypass graft made of a synthetic material. The long-term success of this type of graft is quite excellent at over 90 percent patency at five years. More distal bypass grafts, starting at the groin (femoro-popliteal, or femoro-tibial artery bypass grafts) generally are performed with your own greater saphenous vein. The long-term success of these grafts is less the further one must extend the graft down the lower leg and are usually reserved for limbthreatening conditions (Figure 3). In select patients, synthetic grafts must be used but even less favorable patency rates can be expected. Fortunately, 75 percent of limbs can be salvaged longterm with an aggressive interventional approach.