Helping your patients manage lower-extremity PAD
Alejandro Perez, M.D., FSVM, RPVI
Vascular medicine, Providence Heart and Vascular Institute
Regional medical director, Providence Wound Care and Hyperbaric Services
June 9, 2014
The number of people with peripheral artery disease worldwide has risen dramatically in the past decade, causing some leading vascular experts to warn of a “global pandemic.” As the population ages, the effects of artery-damaging conditions and lifestyle habits take an increasing toll.
While this disease is associated with heart attack, stroke, amputation and other serious outcomes (see Fig. A3), complications can be reduced with proper diagnosis, treatment and patient education.
Atherosclerosis is the predominant cause of peripheral arterial disease of the lower extremities, and the risk for developing PAD increases with age, especially for those 40 and older. Hyperlipidemia, hypertension, hyperhomocysteinemia and elevated C-reactive protein are associated with PAD. Diabetes and chronic tobacco use, however, pose the biggest risks. Each is associated with a three- to four-fold increase in developing PAD.
A vascular history should note any limitations on exertion and should document causes and duration of leg wounds. Pain at rest and with leg position changes also are essential components of a vascular limb history. History of tobacco and nicotine use must be obtained because of the associated risk for PAD.
An important component of vascular examination of the limbs is the pulse examination. Pulses should be graded from 0 to 3:
- 0, nonpalpable
- 1, diminished
- 2, normal
- 3, bounding
The presence of femoral bruit should be confirmed. Feet should be examined for hair loss, ulcerations and compromised skin. Because atherosclerosis is a systemic condition, history and examination also should include other vascular beds with possible disease manifestations.
Evaluation for PAD can be considered for patients with exertional leg symptoms, non-healing wounds, people 50 or older with a history of diabetes or tobacco use, and those who are 65 or older. Universal population screening, however, has not been found to lead to better outcomes.
PAD is most commonly diagnosed by an ankle-brachial index, or ABI. The normal ABI range is 0.91-1.4. Patients with values of 0.9 or less are categorized as having PAD, and those with values below 0.4 are classified as having severe PAD. Values over 1.4 (1.3 in some vascular laboratories) likely are unreliable due to arterial calcification, which is common in diabetics and those with chronic kidney disease.
Further testing of digital pressure may be helpful since digital values typically are not affected by arterial calcification. A normal toe-brachial index is greater than 0.7.
Additional noninvasive tests performed in a vascular laboratory can include segmental pressures, pulse volume recordings, exercise test with ABI, and Doppler evaluation. For better diagnostic accuracy and planning for procedures, CT, MRI and angiographic modalities may be considered.
Often medical management of PAD is not used as fully as possible. Patients with symptomatic PAD benefit from antiplatelet therapy because they are at high risk for cardiovascular events. Statin therapy not only can reduce risk of future cardiovascular events, but it also can help increase walking capacity. ACE inhibitors for blood pressure control also have shown to improve walking distance in PAD patients.
Cilostazol, a phosphodiesterase inhibitor, helps reduce claudication symptoms in many patients. Several randomized trials have shown that supervised exercise therapy is as effective as endovascular therapy for improving walking distance. In addition, unsupervised community-based walking programs also are a practical alternative and are effective in improving exercise capacity. See patient handout.
Addressing tobacco use is particularly important, since patients with PAD who continue to smoke have increased risk for amputation. Smoking-cessation strategies include counseling, nicotine replacement therapy, bupropion and varenicline. Electronic cigarettes have not been proven to be a safer alternative to cigarette smoking.
Critical limb ischemia, or CLI, exists when rest pain or non-healing wounds develop in patients with PAD. Claudication worsens to the level of CLI in 5 to10 percent of patients. Up to 25 percent of CLI patients undergo amputation or die within a year.
When claudication limits activity or if CLI manifests, it’s essential to refer those patients to a vascular specialist. Surgical bypass surgery and endovascular therapies are options available for revascularization. Recent advances in endovascular technology have further increased the potential to improve arterial circulation. It’s important to evaluate and treat acute limb ischemia quickly.
- Identify patients at risk for PAD.
- Use antiplatelet, statin and ACE inhibitor therapy when appropriate.
- Cilostazol and walking programs can help with claudication.
- Partner with patients to develop a smoking-cessation strategy.
- Refer to a vascular specialist when claudication limits activity or if the patient develops critical limb ischemia.
- Hirsch AT, et al. Circulation. ACC/AHA 2005 Practice Guidelines. 2006 Mar 21;113(11):e463-654
- Rooke TW, et al. 2011 ACCF/AHA focused update of the guideline for the management of patients with peripheral artery disease. Vasc Med. 2011 Dec,16(6):452-76