J. Sheppard Mondy, III, M.D., R.V.T., R.P.V.I., F.A.C.S.
Peripheral Arterial Disease (PAD) is the term generally used to describe atherosclerotic disease (hardening of the arteries) affecting the circulation of the lower extremities. Patients with PAD may be asymptomatic, or they may present with symptoms ranging from bothersome Intermittent Claudication (cramping in the calf muscles with exercise) to Rest Pain (pain in the forefoot that is most severe at night) to non-healing sores and even gangrene. The public is generally not aware that PAD is a very common disease that has a tremendous impact on quality of life. Therefore earlier diagnosis and intervention have great potential for improving overall outcome for patients and PAD research will have tremendous impact on the health of future generations.
INTERMITTENT CLAUDICATION: MORE THAN A LITTLE LEG PAIN
Intermittent claudication (IC), from the Latin word, claudicatio – to limp, is an early symptom that can be used as a marker of PAD. It is described as leg pain with exercise that is relieved by a few minutes of rest. The pain is traditionally begins in the calf, but can involve any major muscle group of the lower extremity (calf, thigh, buttock). The pain starts at a predictable distance, and never starts at rest. It is worsened by hurrying, going uphill or walking on uneven ground.
The true number of PAD patients in the general population is difficult to measure, in part because so many patients remain asymptomatic and those patients with symptoms often attribute their discomfort to the aging process. There is a general increase in intermittent claudication with age, and for every symptomatic patient (IC), there are probably another 3 with asymptomatic disease (PAD). Therefore, as many as 10-20% of adults over the age of 65 have PAD. In the 6th and 7th decades of life, claudication may be more prevalent in men than angina (the chest pain of heart disease).
The risk factors for developing peripheral arterial disease are similar to those for other cardiovascular diseases. The relationship between cigarette smoking and PAD has been recognized since 1911. Other classic risk factors for PAD include diabetes, high blood pressure and high cholesterol. A strong family history of heart disease and stroke is also an important risk factor. Since PAD, coronary artery disease (CAD) and cerebrovascular disease (CVD) are all manifestations of atherosclerosis (hardening of the arteries), it should come as no surprise that the 3 conditions commonly occur together.
MANAGEMENT OF PERIPHERAL ARTERIAL DISEASE: FROM PRIMARY CARE TO VASCULAR SPECIALIST
How do we improve outcomes for these patients? The two most important steps towards this universal goal are early diagnosis and cardiovascular risk reduction. Effective intervention to restore circulation in the minority of patients who require intervention completes the strategic initiative.
In the office setting, the diagnosis of PAD and claudication are relatively straightforward, usually from a detailed history and a brief physical examination. The history taken by the clinician will help to identify those patients with risk factors and whose symptoms of leg pain with exercise may be attributable to vascular disease or to another cause (i.e. the joint pain of arthritis, the radiating pain of nerve root compression, the swelling associated with severe venous insufficiency, the nocturnal symptoms of night cramps and restless leg syndrome).
The diagnosis is then confirmed by simple examination and office testing. The single most important part of the physical examination to confirm a diagnosis of IC is to feel for pulses at the ankle and foot. The pulse examination excludes the diagnosis of IC in many patients, establishes the diagnosis in a small group of patients, and identifies a limited group that requires further testing. The most useful screening test for PAD compares the blood pressure measured at the ankle to that measured in the arm (the Ankle-Arm Index or Ankle-Brachial Index, ABI). An ABI of 0.9 or less is indicative of PAD.
Once the diagnosis of PAD is established, treatment options are designed to lessen its impact on the patient. The most important intervention is patient education, and all patients with PAD must be counseled appropriately about the long-term risks for their disease. Treatment of hypertension and hypercholesterolemia and programs for smoking cessation are effective for both coronary and peripheral disease and should become a priority. Diabetic patients should maintain strict glucose control. Mild blood thinner medications such as aspirin and Plavix‚ (clopidogrel) should be started and continued for life to reduce the rate of cardiovascular events. In addition, a program of exercise rehabilitation should be started to improve functional status.
Which patients should be referred to a vascular surgeon? Most frequently, leg symptoms prompt the patient to seek medical attention initially and remain a significant component of the patient’s own perception of well-being. Referral to a vascular surgeon should therefore be considered for every patient with symptomatic PAD, whether or not intervention is felt to be likely. This collaborative approach to treatment should ensure the best outcomes for our patients with PAD.
All patients with symptomatic PAD should have additional simple (non-invasive) testing to provide information regarding the presence, location and severity of the blockages in the arteries. This information is most easily obtained using more formal blood pressure tests at multiple levels on the legs, sometimes accompanied by exercise testing on a treadmill. Ultrasound examination of the arteries supplying the lower extremities can provide similar information, while also helping to identify the exact location of the disease in the arterial tree. Occasionally, a CT scan or MRI will be used to identify the vascular anatomy.
In general terms, only those few patients who are very limited by their vascular disease, or who are at risk for limb loss need to progress further than risk factor modification and baseline testing. Most patients who embark on a regular exercise program will experience at least a doubling of walking distance within six-eight weeks. Cessation of all tobacco use results in an immediate improvement in walking distance as well. The combination of regular exercise and smoking cessation results in sufficient improvement that IC patients who successfully do both may never require invasive therapy.
The next step for those patients who continue to be limited is to try drug therapy. All patients with PAD should already be taking aspirin or clopidogrel (Plavix), but these drugs have little effect on claudication symptoms. Many patients may benefit from the addition of cilostazol (Pletal) to improve pain free walking distance.
Those PAD patients whose symptoms progress despite conservative treatment may be candidates for invasive procedures to improve their lifestyle. Planning for intervention requires an x-ray examination of the blood vessels to identify the exact anatomy and to plan the most appropriate treatment. Most commonly, an arteriogram (similar to a heart catheterization procedure) is performed for diagnosis, and treatment can frequently be performed with balloon angioplasty or stent placement at the same setting. Balloon angioplasty involves threading a tiny balloon into the affected artery under x-ray guidance. Inflation of the balloon then enlarges the channel through which blood flows, thus restoring near normal circulation to the tissues ‘downstream’ from the blockage. Frequently, a small metallic mesh tube called a stent is inserted at the site of the angioplasty to preserve the increased area for blood flow. In most cases these are outpatient procedures requiring a hospital stay of a few hours and recovery of a just a few days. Patients frequently notice an immediate improvement in their claudication pain and an increase in the distance that they are able to walk.
In patients with more extensive arterial blockages (multiple segments in different vessels or long segments within the same vessel) a bypass operation may be a more appropriate procedure. In these procedures, blood flow is routed around the blocked arteries using an artificial blood vessel or one of the patient’s own veins to restore circulation. This is very similar to open heart bypass procedures with which most of us are familiar. These procedures require a several hour operation under anesthesia (general or spinal anesthetic), a longer hospitalization and a longer recovery. However, the results of these bypasses are generally quite good and benefits usually last for years. Given the choice, most people would opt for the minimally invasive procedures over operation; however, all decisions for treatment must be individualized for each patient, offering the safest procedure with the best long term durability for the particular lesion treated.
As PAD is so commonly encountered but under-recognized, earlier diagnosis and risk factor modification is important in improving outcome. For those patients with significant symptoms, a vascular specialist who performs the full range of minimally invasive and traditional bypass operations is best qualified to help guide the patient through the complex and growing list of treatment options, tailoring the procedure to the specific situation. The goal of therapy is always to help PAD patients return to the activities and lifestyle that they enjoy free of pain and significant limitation.
Dr. Mondy is a board-certified vascular surgeon, specializing in general surgery and critical care at Savannah Vascular and Cardiac Institute and can be reached at (912) 352-VEIN or firstname.lastname@example.org.