According to recent estimates, more than 15 million Americans have peripheral arterial disease (PAD), a disease characterized by atherosclerotic occlusive disease of the lower extremities. “About 20% to 25% of patients with diabetes who are older than 50 has PAD,” says Peter Sheehan, MD. “Estimates are even higher in the Medicare population with diabetes. About 30% of diabetics aged 65 and older have PAD.” Of those with PAD, more than half are asymptomatic or have atypical symptoms, about one-third have claudication, and the remainder have more severe forms of the disease. Cardiovascular event rates in patients with PAD and diabetes are higher than those of their non-diabetic counterparts.
Research has shown that PAD is a major risk factor for lower-extremity amputation, and it is also accompanied by a high likelihood for symptomatic cardiovascular and cerebrovascular disease. “Even for asymptomatic patients, PAD is a marker for systemic vascular disease involving coronary, cerebral, and renal vessels,” Dr. Sheehan says. “This increases the risk of myocardial infarction, stroke, and death.” He adds that diabetes and smoking are strong risk factors for PAD. Other well-known risk factors are advanced age, hypertension, and hyperlipidemia.
Making the Diagnosis
Diagnosing PAD is of clinical importance because it helps identify patients at high risk of heart attack or stroke, regardless of whether symptoms of PAD are present, and because it enables clinicians to elicit and treat symptoms. “Each patient with diabetes who has PAD will have varying symptoms and atherosclerotic disease,” says Dr. Sheehan. Accordingly, the American Diabetes Association recommends that patients have their feet checked regularly to assess for signs of foot complications and possible PAD (Table 1).
Dr. Sheehan says that identifying patients with subclinical PAD and using preventive measures may make it possible to avoid future health problems. “Early identification of PAD may enable us to improve quality of life by helping patients avoid long-term disability and functional impairment,” he adds. “It can also help us reduce the economic costs of healthcare, reduced productivity, and personal expenses associated with PAD.”
Several tests may be required to diagnose PAD and determine the extent of the disease. “The initial assessment should begin with a thorough medical history and physical examination,” says Dr. Sheehan. “This can help identify people with PAD risk factors, symptoms of claudication, rest pain, and functional impairment.” The ankle-brachial index (ABI) can be of particular help because it is non-invasive and provides information on PAD severity. A screening ABI should be performed in patients aged 50 and older who have diabetes. If the test comes back normal, it should be repeated every 5 years. Clinicians should consider a screening ABI in patients with diabetes who are younger than 50 if other risk factors are present.
Treating PAD risk factors may help improve cardiovascular outcomes in people with both PAD and diabetes. Treatment should focus first on primary and secondary risk modifications, and then progress to treating PAD symptoms and limiting disease progression. “Clinicians should strive to get patients to quit smoking, control their A1C levels, and keep their blood pressure and cholesterol levels in check,” says Dr. Sheehan. “This requires that patients be educated thoroughly about their disease and the actions they can take to manage it [Table 2].” He adds that statin and antiplatelet therapy can also be of benefit for select patients with PAD. Other treatment strategies that have shown promise, particularly in symptomatic PAD, include exercise rehabilitation and the use of pharmacologic agents.
“Early identification of PAD may enable us to improve quality of life by helping patients avoid long-term disability and functional impairment.”
In addition to these less invasive approaches, Dr. Sheehan says there have been many advances in surgery and endovascular therapy for patients with PAD. “About 10 years ago, most patients with symptomatic PAD required surgery at some point to treat the disease. Since that time, endovascular approaches have improved significantly. Many patients with PAD are now undergoing endovascular treatment to avoid more invasive open procedures, and they’re experiencing similarly good outcomes but with shorter hospital stays and fewer complications. That said, the learning curve associated with endovascular approaches is steep. The more experience a clinician has with these treatments, the better the outcomes.”
The selection of treatment for PAD is often a complex decision that requires team consultation. Research suggests that most amputations can be prevented and limbs can be salvaged, but the key is to identify PAD as early as possible. “Treatment decisions should be made on an individual basis, taking into consideration rehabilitative and quality-of-life issues,” says Dr. Sheehan. “Clinicians should work collaboratively with other specialists in the management of this complex patient group. Ultimately, the goal is to reduce vascular events that too often result in disability, social decline, and death.”
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