Dr. Niren Angle

UCSD Section of Vascular and Endovascular Surgery

Appointments (619) 543-6980

Peripheral Arterial Disease (PAD)

What is PAD?

Peripheral arterial disease (PAD) is a blood vessel disorder that afflicts millions of Americans today and is likely to afflict millions more as the population continues to get older.  In PAD, obstruction of the arteries reduces the blood flow to the muscles downstream of the affected arteries, most commonly in the legs.  Like coronary artery disease, which is a disease of the arteries that supply the heart, PAD is a blood vessel disease whose most common cause is atherosclerosis, or hardening of the arteries due to the buildup of plaque.  Thus, PAD and coronary artery disease are two blood vessel diseases that affect different parts of the body but have the same cause.

Who Is Likely to Get PAD?

Atherosclerosis is most commonly present in patients who have risk factors such as elevated cholesterol levels and lipids, high blood pressure (hypertension), smoking, dietary indulgence, and lack of exercise.  As potent as these risk factors are for the development of atherosclerosis, a risk factor that one still cannot control is one’s genetic predisposition to such risk factors.  Each individual has a genetic profile that determines how susceptible he or she is to any combination of the risk factors. 

Atherosclerosis is a disease of aging, and the disease manifests itself in its most severe form in older individuals, but it clearly starts much younger, perhaps as early as the teenage years.  For this reason, early modification of risk factors and good habits is critical.  One can reduce the effects of atherosclerosis even if one cannot completely avoid it. 

What Are the Symptoms of PAD?

PAD most commonly afflicts the legs and is manifested by symptoms such as pain upon walking.  In its most severe form, PAD is associated with gangrene or ulcerations with poor or no healing.  PAD is a spectrum, ranging from the mildest form that causes pain in the legs upon walking to the most severe form that can result in amputation of the leg. 

It should be emphasized that the milder forms of PAD do not necessarily lead to the more severe forms.  Before any intervention is entertained, it is important for the patient to be evaluated by a vascular surgeon who will determine whether anything needs to be done and if so, what that treatment should be.  It is important that the specialist who evaluates the patient is skilled in the natural history of the disease, is thoroughly familiar with the pros and cons of any intervention, and is able to care for the patient throughout the entire spectrum of that disease. 

PAD is also important because its presence identifies a patient who is at a higher risk of having heart attack or stroke.  It has been shown clearly that patients who have PAD, as manifested by a reduced ankle-brachial index (see below), have a reduced life span compared to patients with normal ankle-brachial indices.  Therefore, it is important not only to treat PAD in terms of the leg problems but also to have an aggressive approach to modifying risk factors and screening for other conditions that may be silent but deadly.

The term PAD, as stated above, categorizes a wide spectrum of symptoms and conditions. Each of these conditions is described in detail below. 

Intermittent Claudication

In intermittent claudication, a patient develops an aching pain, usually in one or both calves, after walking a certain distance.  The patient may feel cramping pain upon walking, an aching pain, or a heaviness or fatigue of the leg.  There are several types of intermittent claudication: arterial, venous, and neurogenic.  Arterial intermittent claudication is the most common and is the one that we will focus upon here.  Knowledge of the other two types of intermittent claudication is important because the ability to distinguish one from the other is critical.  Treatment can be offered only after a firm diagnosis of the precise cause of leg pain is made. 

Arterial Intermittent Claudication

Arterial intermittent claudication is notable for the fact that it almost always occurs after the patient walks the same distance and is relieved when the patient stops walking.  If the patient has to change positions or the pain comes on without walking or at various distances upon walking, the diagnosis of an arterial cause of this leg pain is highly suspect and should be confirmed by other more objective measures.  Occasionally, the patient will have pain that involves the hips, buttocks, or thighs, and this signifies blockage in the arteries above the legs, most commonly in the arteries running through the pelvis. 

Intermittent claudication is a benign disease in and of itself in the sense that not having a procedure done to relieve this set of symptoms will not lead to an eventual amputation of the leg in the vast majority of patients.  For this reason, the decision to offer an intervention of any type must be based on other factors rather than the fear of losing one’s leg.

Diagnosing Arterial Intermittent Claudication

If the patient has symptoms of leg pain upon walking, a vascular specialist will be able to identify quite easily whether this condition is likely to be due to arterial disease or something else.  A confirmatory study is important.  The ankle-brachial index test is the test used most commonly to rule in or rule out an arterial cause of leg pain upon walking.  In this test, blood pressures are measured throughout the course of the leg at rest and sometimes upon exercise to see whether the blood pressure at the legs is reduced compared to the blood pressure in the arms.  This is an indirect indication of the degree of obstruction to flow, presumably due to blockages of the arteries in the legs.  This test is very useful in the great majority of patients.  In diabetics it may be of limited use, however, because diabetics tend to have calcification of their vessels, making blood pressure measurements in the leg less accurate. 

Once the cause of the patient’s symptoms has been confirmed with this ankle-brachial index test, the next step is to determine what, if anything, needs to be done about it.  This largely depends on the patient.  The reason for this, as stated before, is that left unattended, intermittent claudication is not a serious risk in terms of limb threat.  However, if the patient’s leg pain upon walking is significantly disabling his or her lifestyle, then an intervention for the claudication is appropriate.  Obviously, the definition of disabling is very subjective and depends on the patient, his or her age, occupation, and daily activities.  If the vascular surgeon and the patient feel that this claudication is something that should be treated, then many possibilities are open.

The next step, then, is to determine where the blockage is. A variety of techniques can be used to do this.  The most commonly used test is a contrast angiogram in which a catheter, which is a hollow tube, is inserted into the arteries, contrast is administered into the arteries, and a picture of the arteries is obtained, thereby showing where the narrowing or blockage may be.  Alternatively, less invasive tests such as an MR angiogram or a CT angiogram can also be used.  These tests have their limitations, however, and do not really represent a significant improvement over a contrast angiogram.  If the patient opts for treatment of the claudication, an angiogram is then performed and based on those findings, treatment options are formulated.

Treating Arterial Intermittent Claudication

If the narrowing affects a limited part of the artery, then an endovascular approach can be utilized.  Unlike a traditional operation, an endovascular approach is a treatment that is done inside the blood vessel through the very catheters that are inserted to do the angiogram.  The benefit of this is that it is much less invasive.  There are no large incisions to heal and there is little or no pain.  The most commonly utilized endovascular therapy is a balloon angioplasty, in which a balloon is inflated in the artery and the plaque obstructing the artery is dilated. 

Depending on which artery is being treated, a stent may be inserted during the angioplasty.  A stent is a metallic mesh tube that is placed at the site of the narrowing to open the artery up.  Unfortunately, stents have a very poor outcome in arteries below the groin.  In the majority of cases, stents placed in these arteries are virtually guaranteed to have restenosis, that is, a re-narrowing of the very artery that was treated. 

Although the endovascular approach is a very useful approach that limits pain and is associated with a much faster recovery, it tends to have an earlier failure rate than traditional bypass.  However, it is an appropriate and excellent therapy to use when the narrowing is reasonably limited and the patient is aware that more interventions will probably be necessary in the future as restenosis may occur.

The second option is to perform a surgical intervention.  In a great majority of cases, this  involves a bypass.  The bypass utilizes a conduit, either the patient’s own vein or a synthetic graft, to bypass the obstructed artery.  The benefit of this approach is that it is much more durable than endovascular treatment.  The disadvantage of this approach is that it obviously involves an operation with regional or general anesthesia, and recovery from the operation is longer than with the endovascular approach.  The recovery can be quite brisk, however, depending on the extent of the operation required. 

Selecting the appropriate treatment option for a patient is a decision that must take the patient’s individual situation into account.  Surgical bypass may be the preferred alternative in patients in whom the disease is too diffuse or involves a much longer segment of artery.  There are many situations in which an endovascular approach may be technically feasible, but a surgical bypass makes more sense.  This kind of judgment is best done by the vascular surgeon in consultation with the patient, as the vascular surgeon has no particular vested interest in one therapy versus the other. 

Thus, intermittent claudication is a condition that is a reflection of atherosclerosis in general and is relatively benign in terms of long-term risk to the legs.  If treatment is desired, then an endovascular approach or a surgical approach may be utilized depending on the extent and location of the disease.  If you are an individual who has PAD, it is important to discuss your case with your vascular surgeon in order to determine the treatment that is most appropriate for you. 

A rigorous walking program is a very useful first therapeutic strategy for patients who have intermittent claudication that is not lifestyle disabling but is bothersome enough to motivate them to seek treatment.  Multiple studies have shown the effectiveness of a walking program for a specified amount of time wherein the patient walks until he or she feels the pain and then walks through that pain.  Over a period of weeks or months, most patients will be able to nearly double their walking distance.  The only caveat to this is that walking programs are not very useful if there is significant amount of blockage in the arteries above the legs causing intermittent claudication.  However, an exercise program in general is a useful and necessary strategy for the modulation of claudication as well as for general cardiovascular health. 

Thus, intermittent claudication due to PAD must be addressed on two levels: the symptoms affecting the legs on one level and the fact that intermittent claudication due to PAD is a marker for the systemic condition of atherosclerosis. The treatment depends on whether the patients lifestyle is affected significantly by the claudication  and if therapy is needed, it can range from conservative management with walking program to intervention with endovascular therapy such as balloon angioplasty, atherectomy, and cryoplasty versus surgical bypass.  As far as its indicator of atherosclerosis, it is critically important to initiate an aggressive strategy of modulating risk factors such as hypertension(high blood pressure), hyperlipidemia (increased cholesterol/trigylcerides), smoking cessation, along with a focused approach on diet and exercise. This risk factor modulation, particularly vis-à-vis dietary modulation and exercise are commonly underemphasized.