Cath Lab Digest

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Abstract

Lower extremity arterial disease (LEAD) is estimated to affect one third of individuals older than 65 years of age, occurs in younger individuals who use tobacco or have diabetes mellitus (DM), and often remains undiagnosed until a patient presents with ischemia-related symptoms or complications. Valid and reliable noninvasive tests such as the ankle-brachial index (ABI) are recommended to detect LEAD. However, ABI results can be inconclusive or the index can be elevated (ie, >1.3) in persons with calcified ankle arteries due to DM, renal failure, or arthritis. In these instances, obtaining toe pressure (TP) measurements, which correlate well with angiographic findings, is advised, providing the patient does not have vasoconstriction with cold toes or vasospastic disease. In such cases, TP can be obtained using a portable photoplethysmograph (PPG), which offers a simple and inexpensive method for healthcare providers in a variety of clinical settings to assess for the presence of LEAD. Portable PPG TP measurements have been found to have a high level of agreement with vascular laboratory PPG tests to detect LEAD, as well as good sensitivity and a high specificity. Adopting a TP measurement protocol of care to assess high-risk individuals such as patients with DM and elevated ABIs potentially can have a major impact on early identification of LEAD and reduce the risk of ischemia-related complications, including lower extremity wounds and amputations.

Keywords: lower extremity arterial disease, diabetes mellitus, assessment, screening, toe pressure

Index: Ostomy Wound Management 2011;57(11):36–44

Potential Conflicts of Interest: none disclosed

  Lower extremity arterial disease (LEAD), also known as peripheral arterial disease (PAD), is a chronic, progressive disorder related primarily to atherosclerosis. The disease is estimated to affect 10% to 15% of the US population¹ and up to 30% of adults older than 65 years of age worldwide.^2-9 LEAD also occurs in persons younger than 60 years who use tobacco or have diabetes mellitus (DM).¹⁰ Up to 25% of persons with LEAD will develop critical limb ischemia within 5 years of onset¹¹ and 3% to 8% will have limb loss.¹² For persons with DM, LEAD is a problematic coexisting condition. In 2007, $116 billion was expended in the US for direct costs of treating DM and its complications, and $58 billion was lost in reduced national productivity.¹³

  Unfortunately, LEAD is often not recognized by many patients or physicians until a complication such as severe pain, a nonhealing wound, or infection leading to limb loss occurs. According to a review of epidemiologic studies by Criqui,¹⁴ individuals with reduced arterial perfusion can be asymptomatic because <50% of persons with LEAD exhibit its classic symptom of intermittent claudication (ie, calf pain with exercise); leg pains are often mistaken for normal aging or arthritis. Several studies (see Table 1)^7,15-22 have shown LEAD can be asymptomatic and not diagnosed in up to approximately 50% of patients when measures such as pulse palpation or a history of claudication are relied on to diagnose LEAD instead of using more reliable tests such as ankle-brachial index (ABI). Also, Hirsch et al¹⁵ reported that many physicians fail to treat LEAD, even after it is identified, as aggressively as cardiovascular disease.