Over the past 7 years I have had the wonderful opportunity to run the Kaiser Permanente Peripheral Artery Disease (PAD) rehabilitation program in Denver, Colorado, where my services have been covered by insurance (not Medicare). The following blog series is based on available research as well as my own personal observations and experience.
Compared to the volume of articles published over the years on exercise and heart disease, peripheral artery disease (PAD) takes a back seat. PAD narrows blood vessels, reducing blood flow through the arteries outside the heart, most notably the legs and carotid arteries in the neck. It is typically caused by injury to artery walls that results in inflammation, mainly from risk factors similar to those of heart disease, with smoking often the main contributor. The inflammation causes a build-up of plaque through a series of ruptures, and even in mild cases, a larger rupture can form a clot that can cause sudden blockage of the artery (known as acute limb ischemia in the legs or arms, or a stroke if in the carotid arteries).
Despite the relative lack of attention in comparison to heart disease, there is good information available about how exercise can improve symptoms of PAD-caused claudication, or pain during physical activity that is caused by a lack of blood flow. But because the volume, intensity and mode of exercise used in research interventions varies widely, the information can be confusing, which makes it difficult to design the best program for any one individual.
This blog series will discuss existing research, look at both well-documented and non-traditional methods and modes of exercise, and discuss how to bring together all aspects of training to get optimal client results.
The typical symptom of PAD is claudication caused by a lack of adequate blood flow (or ischemia) to the skeletal muscle. The word "claudication" comes from the Latin "claudicare" meaning "to limp." The Roman emperor Claudius (who ruled from A.D. 41-54) was so named because he limped, probably because of a birth defect.¹
Only a small percentage of patients (around 10%) will actually complain about claudication. Approximately 40% may never develop symptoms, while 50% may have more atypical symptoms that are harder to diagnose from history alone.² There are multiple classifications for which to grade the severity of claudication, such as the Fontaine scale:
- Stage 1 - No symptoms
- Stage 2 - Intermittent claudication
- 2a - no resting pain, onset of claudication in more than 200 meters
- 2b - no resting pain, onset of claudication in less than 200 meters
- Stage 3 - Nocturnal and/or resting pain
- Stage 4 - Necrosis (death of tissue) and/or gangrene in the limb
Claudication is characterized by an aching, cramping pain in the calves, thighs and hips resulting from exercise such as walking. Though the pain often subsides with rest, it can be reproduced consistently with the same type of exercise.
Other Symptoms & Sensations
Symptoms of claudication can also have various other sensations such as aching, muscular fatigue, and burning in the legs. Similar to angina from the heart, this discomfort can come in various forms. When taking a patient's history, it is important to establish a pattern of exertional symptoms that do not have another cause, such as neuromuscular or musculoskeletal origins.
Alternative Causes of Claudication
Other potential causes of claudication symptoms may include: spinal canal stenosis, peripheral neuropathy, peripheral nerve pain, herniated disc impinging on sciatic nerve, osteoarthritis of the hip or knee, venous claudication, symptomatic Baker's cyst, chronic compartment syndrome, muscle spasms or cramps, or Restless Leg Syndrome.³
Anyone who has interviewed enough people with symptoms of claudication from PAD understands that not all leg pain is the same. Symptoms can vary greatly depending on the location, number, and length of occlusions, prior exercise training history, how much exercise they continue to do and co-morbidities.
In the next post on diagnosing and treating PAD, we'll be exploring how we can better diagnose the condition by comparing the symptom sets of conditions with similar instances of claudication.
Mark Patterson, M.Ed., is Chair of ACSM's Registered Clinical Exercise Physiologist Board and is an ACSM/ACS-certified Cancer Exercise Trainer who works in Cardiovascular Services for Kaiser Permanente in Colorado. He currently runs a consultation and evaluation service for both Cardiology and the Department of Vascular Surgery.
He likes to spend his time at home in the mountains of Colorado with his family and dogs, watching moose, mountain lions and the occasional bear walk through his backyard, and stubbornly still pursues trying to run a sub-5 minute mile after age 40. He is now 43 and still working on it.
¹ ACSM's Exercise Management for Persons with Chronic Diseases and Disabilities, 3rd Edition, Human Kinetics. 2009.
² PAD Toolkit - PAD Coalition - developed by AACVPR / Vascular Disease Foundation - 2010
³ www.medterms.com (August 2011) - definition of claudication