Debunking Five Myths in Peripheral Arterial Disease

Leslie Cooper, MD: Greetings, I'm Dr Leslie Cooper, chair of the department of cardiovascular diseases at the Mayo Clinic in Florida. During today's "Trending Topics" video, we will be debunking five myths regarding peripheral arterial disease (PAD). I'm joined by my colleague, Dr Amy Pollak, who specializes in cardiovascular medicine and preventive cardiology. Welcome, Amy.

Amy Pollak, MD: Thanks, Leslie.

Myth 1: PAD Commonly Causes Cramping

Dr Cooper: Myth number one, individuals with lower-extremity peripheral arterial disease present with classic intermittent symptoms, such as cramping in the calves when they walk. Amy, what are the most common clinical presentations of patients with peripheral arterial disease?

Dr Pollak: Leslie, I love this myth because, as you know, only 10% of people who have lower-extremity peripheral arterial disease actually present with the symptoms of classic intermittent claudication which, as you pointed out, is cramping discomfort in the calves that comes on when you walk and that goes away when you rest. It is interesting to me that only 10% of individuals will have that typical presentation.^[1]

Forty percent of people will have symptoms of atypical claudication. They'll have some leg discomfort or fatigue. Often, it's chalked up to being related to osteoarthritis or neuropathy—maybe a myopathy—but not attributed to peripheral arterial disease.

Up to 50% of individuals are classified as asymptomatic, which is probably a misnomer, because so many patients who have peripheral arterial disease will cut back on what they're doing in terms of the amount of activity—the amount of exercise—to the point that they're not having symptoms. But [they seem asymptomatic] because they're not pushing themselves to be as active as they once were. Importantly, patients can also present with symptoms of chronic critical limb ischemia or acute limb ischemia, and that's where there is a severe cutoff of blood flow to the leg.

In patients who have more stable symptoms, we need to think about them as either having typical claudication, atypical claudication, or falling into this misnomer of asymptomatic disease where they may actually have cut back on the amount of activity that they're doing.

Myth 2: Resting ABIs 0.91-0.99 Exclude PAD

Dr Cooper: It is important for clinicians in practice to recognize the many different presentations of peripheral arterial disease.

Our second myth is that an ankle-brachial index (ABI) of 0.94 at rest excludes the diagnosis of peripheral arterial disease. Amy, how do you interpret a resting ankle-brachial index?

Dr Pollak: Another great question and an important myth. Ankle-brachial indices: What does that really mean? We're taking the systolic blood pressure in the ankle, and we're dividing that by the systolic blood pressure in the brachial arm, and you're using the higher of whichever arm blood pressure you get. You can have the right ankle matched with the left arm, if that's the higher blood pressure.

We're looking for that ratio. You should have a ratio, that ankle-brachial index, between 1 and 1.4. That's considered normal. If it's >1.4, often that indicates noncompressible arteries and is a sign of atherosclerosis. An ABI of <0.9 is clearly abnormal.^[2]

Importantly, you have a borderline category of 0.91 to 0.99, and that's an important category of patients to remember when you're getting results of an ABI, because it's hard to say, from that test result alone: Are they clearly normal, or are they clearly abnormal?

What's helpful to do in that situation is to have individuals exercise—walk on a treadmill or do calf raises—and then to retest the ABI after they finish exercising. And if you see a fall in the ABI by 20%, then that diagnoses peripheral arterial disease. Clinicians can't be too reassured by an ABI that falls in that borderline range of 0.94. You have to consider the patient's symptoms and then consider doing a repeat ABI after exercise.

Myth 3: Asymptomatic PAD Is Benign

Dr Cooper: So helpful, especially in diabetics where stiff vessels could lead to a false impression of normal when really there's just as much risk in the higher stiff vessels as in the lower ABI patients.

Our third myth is that as long as patients with peripheral arterial disease are not symptomatic, that this is a fairly benign disease. Amy, since the finding of peripheral arterial disease represents underlying atherosclerosis, what do we know about cardiovascular risk in patients with minimally symptomatic peripheral arterial disease?

Dr Pollak: Such an important area. Peripheral arterial disease, as you pointed out, represents underlying systemic, oftentimes, atherosclerosis. These individuals are, essentially, at equivalent risk for heart attack, stroke, or cardiovascular death as their counterparts with coronary artery disease.

Patients who have peripheral arterial disease—as ABI goes down, indicating more severe disease—are at even higher risks of heart attack, stroke, or death. Interestingly, there are some sex-specific differences there, such that a woman with peripheral arterial disease, compared with a man with the same degree of PAD based on the ankle-brachial index, is at higher risk of heart attack and death.^[3]

Myth 4: PAD Primarily Affects Men

Dr Cooper: That's so important, and women are often undertreated for cardiovascular risk factors. This is one more reason why it's important to recognize sex-specific differences in atherosclerosis.

Our fourth myth is that peripheral arterial disease primarily affects men. We now understand that peripheral arterial disease affects both women and men. Amy, please tell us some of the sex-specific differences in peripheral arterial disease.

Dr Pollak: As we touched on in the last myth, we certainly know that there are more women with peripheral arterial disease than we previously thought. When you look at [people] over the age of 80, 29% of men have peripheral arterial disease, and about 25% of women.^[4]

If you use census data [to estimate the numbers of people affected], it suggests that there are actually more women than men living with peripheral arterial disease because women tend to live longer than men do. Peripheral arterial disease is a problem of both sexes. Women tend to have more atypical symptoms than men. Women tend to be more "asymptomatic," but often that is misnomer because maybe they aren't exercising enough to be able to bring out those symptoms.

Interestingly, women present more often with life-threatening limb ischemia than men do. There is a higher risk of cardiovascular death in women than men with peripheral arterial disease, both in stable outpatients as well as in women after revascularization, whether it's stenting or bypass surgery. We don't fully understand why there are some of these sex-specific differences in PAD, but that certainly is an active area of research.

Myth 5: Symptomatic PAD Requires Revascularization

Dr Cooper: Indeed. I imagine it's important with atypical symptoms and higher risk to make that diagnosis, to do a careful pulse exam, and if there's edema and the pulses can't be felt, raising the legs, perhaps, for 30 seconds to look for elevation pallor.

Our fifth myth is that treatment for symptomatic peripheral arterial disease always requires revascularization. For patients with peripheral arterial disease and stable exertional symptoms, Amy, what is your recommendation for medical treatment, and when do you consider revascularization?

Dr Pollak: There's this reflex: When you find that someone has symptomatic peripheral arterial disease and [the person has] an aorto-iliac lesion you want to immediately send them off for revascularization. But there is more than one appropriate strategy for those individuals.

The CLEVER trial looked at this very topic.^[5]The study took a little over 100 patients who had symptomatic peripheral arterial disease, whose mean ABI was under 0.7 and who had a lesion in their aorto-iliacs. [Researchers] randomized patients to one of three groups: 1) optimal medical treatment (for example, being on aspirin or a statin; stopping smoking; optimizing their diabetes); 2) optimal medical therapy and a supervised exercise program where the patients came in three times per week for 12 weeks; or 3) optimal medical therapy and a stent.

Interestingly, the study found that the patients who were randomized to the treadmill—so they didn't get a stent—actually had the best improvement in their treadmill performance. The group that received a stent had a higher quality-of-life score and seemed to have better walking scores in terms of their daily life. So, both groups improved, whether or not they were treated with exercise or with a stent.

My practice: If somebody has stable exertional claudication, symptoms involving their legs, and significant peripheral arterial disease, then the first thing to do is optimize their medical treatment. It's imperative to stop smoking; to manage their diabetes; to try to get their hemoglobin A_1c <7. These individuals need to be on an aspirin to prevent heart attack and stroke; need to be on lipid-lowering therapy, most often with a statin; and they need to get into an exercise walking program.

If patients are still having lifestyle-limiting claudication despite optimal medical therapy and they have a lesion that's amenable to intervention, then absolutely intervene at that point, but we don't need to jump the gun and go right to intervention. Medical therapy is so important, and getting into a supervised exercise program is challenging because of reimbursement. However, home-based exercise programs have been studied and are quite effective as well. Getting into a regular exercise program is so important.

 When to Use Cilostazol? 

Dr Cooper: Excellent. When do you use cilostazol?

Dr Pollak: That's a great question. It can certainly help patients who have symptomatic claudication. The challenge is you can't use it in anyone who has congestive heart failure, and it's important for clinicians to remember that almost half of our patients with heart failure have heart failure with preserved ejection fraction. So you need to have a close watch on whether these patients are having lower-extremity edema due to undiagnosed heart failure with preserved ejection fraction—in which case, they wouldn't be a candidate for cilostazol.

But if someone stops smoking; their diabetes is managed; they're on an aspirin and statin; and still having some exertional symptoms, no signs of heart failure, then you could use cilostazol.

Dr Cooper: Thank you very much. Amy, these were important insights. Thanks to our viewers for joining us today on theheart.org on Medscape.

© 2016  Mayo Clinic

Cite this: Amy W. Pollak, Leslie T. Cooper. Debunking Five Myths in Peripheral Arterial Disease - Medscape - May 23, 2016.