How To Diagnose Peripheral Arterial Disease
Peripheral arterial disease can result in a range of serious complications and possible death. Accordingly, this author offers a closer look at non-invasive testing and assesses the pros and cons of these tests at the microcirculations and macrocirculation levels
Peripheral arterial disease (PAD) affects 10 to 20 percent of the United States senior citizen population, approximately 8 million people. These PAD patients experience significant and costly morbidity such as leg amputation and death.1 There is a 20 percent incidence rate of PAD in patients 75 years of age and older. Despite the prevalence of the disease and associated cardiovascular risk, only 25 percent of these patients with PAD undergo treatment.2
Early diagnosis and treatment of PAD not only improves one’s quality of life, it can save lives. According to the REACH Registry, approximately 16 percent of PAD patients have other incidental atherosclerotic changes in the brain, such as cerebrovascular disease (CVD), and/or in the heart with coronary artery disease (CAD). These deadly “clogged artery” problems are collectively called “polyvascular diseases.”2 Consequently, PAD patients have a mortality risk that is two to three times greater than patients who do not have PAD.3 It should be emphasized here that PAD is not just a “leg cramping problem” but an ominous sign of death that requires our close attention.
Diabetes also presents as a separate and significant risk factor of PAD. As obesity becomes the norm in America, diabetes will similarly become more commonplace. Currently, the diabetic population represents 20.8 million patients, about 7 percent of the U.S. population.4 The recently released 2006 American Diabetes Association consensus statement presented clinical data that one in three patients with diabetes mellitus (DM) are known to have PAD. The statement urged clinicians to participate actively in the diagnosis and treatment of this disease.
Recognizing The Challenges Of Diagnosing PAD
However, diagnosing PAD can be confusing for many clinicians. Although we often associate PAD with intermittent claudication (cramping calf pain caused by walking), this classic symptom accounts for only 10 percent of the entire PAD patient population over the age of 50. Surprisingly, up to 50 percent of the PAD patients are known to be asymptomatic while 40 to 50 percent of PAD patients may present with atypical, non-specific complaints in their legs.5
To complicate the issue, diagnosing PAD can be challenging from both a visual and clinical standpoint. A recent systematic review of PAD clinical studies found that a physical examination of the lower extremities (e.g., palpation of pulses and “classic findings” such as atrophic skin change or lack of hair growth) alone is unreliable and “not independently sufficient to include or exclude the diagnosis of PAD.”6 The study concluded with a strong recommendation for the use of non-invasive vascular tests to screen patients for PAD upon each exam.6
In consideration of the current statistics, do not ignore the importance of non-invasive vascular tests of the lower extremities. The Podiatry Insurance Company of America (PICA) group recently reported two legal cases in which podiatric physicians “failed to make a correct diagnosis” of severe PAD and revealed a “lack of documentation” of the pre-op vascular workup.7 Both cases resulted in lawsuits initiated by patients who underwent below-knee amputations. One can easily avoid these unfortunate events by using the right tools to assess our patients effectively and non-invasively.
What You Should Know About Non-Invasive Vascular Testing
Whenever one suspects PAD, the clinician must perform non-invasive vascular testing. Given the current medical evidence, one may expect to encounter PAD in patients with any of the following histories: