PAD month a call to action
Losing a leg is a life-altering event and too often a life-ending one. Although the number of leg amputations has decreased over the years, there are still too many. The statistics regarding the long term survival of a leg amputation are poor: more than two-thirds die within 3 years after a leg is amputated (when the reason is not trauma). This is life-changing in every sense of the word. By saving a limb, we are saving a life.
The worst part is most of these are preventable. If the condition leading to the amp had been treated early enough, the limb never would have needed to be removed. The condition most commonly resulting in an amputation is peripheral arterial disease, aka PAD, a chronic circulatory condition which affects approximately 18 million Americans. September is PAD Awareness Month, and this article is dedicated to all the readers who are developing PAD but not yet aware of it. Most of the time, those suffering with PAD are ignorant of its presence until a real problem develops. Like a myocardial infarction, it’s a silent killer, although on a very different timeline.
The basic problem in PAD involves the tubes blood flows through, our arteries, which become narrowed or blocked. This results in a reduction in the amount of blood reaching the tissues past the blockage. This is not a sudden, dramatic blockage but occurs gradually, subtly, over time. And so the disability and physical changes take place slowly and quietly, typically unnoticed.
Who is at risk for PAD? Genetics is naturally a critical factor, but diet and lifestyle are as well, and the latter two we have some control over. Identified risk factors include cigarette smoking, diabetes, high blood pressure, high cholesterol, kidney disease, and being over 60 years of age. A diet dominated by red meat and saturated (or trans) fats has been identified as a consequential risk factor, while a Mediterranean diet apparently promotes good artery health.
Blood is an amazing substance, carrying oxygen and nutrients to all corners of the human body. Every living cell in the human body requires these essential substances to survive and even thrive. If the blood supply is cut off, gangrene occurs. This is tissue death and there is no recovery possible for those structures. But more often, this slow but progressive reduction in flow means unhealthy tissues. Skin become more fragile, dry and thin, slower to heal. Wound healing without adequate blood supply is impossible. (The very accurate aphorism in wound care is “we are held hostage by the blood flow.” Regardless of the fancy graft technology or expensive wound medicine used, a wound will not heal without blood.)
The reasons PAD too often goes undiagnosed are many. A critical factor is the location of many of the early changes: the feet. They are the structure farthest from the heart, so there’s a lot of opportunity for clogging of the arteries. The most obvious transformations are cutaneous (the skin), as well as other skin structures. One of the structures most sensitive to reduced blood supply are hair follicles. As flow lessens, the affected area of the limb becomes hairless. The difference can be dramatic, the sudden absence of hair at some well-defined level. Nail changes are also common, but are simply passed off as nail fungus.
How many visits to your primary care provider include shoe removal and a foot inspection? “Out of sight, out of mind” is the apropos cliche. These changes go unseen and undetected too often, unless you are seeing a podiatrist (although that is no guarantee of being diagnosed). A physician needs to have a high index of suspicion and be ever-vigilant to the changes of peripheral arterial disease. The presence or absence of pulses in the ankle is easy to assess, but not particularly informative. Either is not definitive for healthy blood vessels or the presence of vessel disease.
The symptoms of PAD have many potential manifestations, some of which are actually diagnostic. One is ‘intermittent claudication’, in which the sufferer develops pain in the leg or foot when they walk a certain distance. This pain is relieved by rest, recurring with ambulation of a similar distance. This is the classic ‘walk-pain-rest-relief’ cycle.
As the disease progresses, the amount of blood getting to the periphery decreases further. At some point, pain can develop at night when recumbent, ie lying down. Without the assistance of gravity, when not upright, there will be reduced flow to the tissues of the foot and leg. Any tissue deprived of sufficient oxygen become ischemic, meaning sickened due to inadequate oxygen. When this situation develops, severe pain ensues. Those suffering “rest pain” find they simply have to stand or even dangle their legs off the bed to obtain relief, giving them their gravity assist.
Blood vessel disease can involve arteries all over the body. And a strong correlation exists between PAD with heart disease and stroke. Those are essentially artery problems as well. If you are diagnosed with PAD, you should also be screened for these other conditions. The vessels going to the brain may also be effected, which often elicits no symptoms but predisposes one to suffering a stroke.
Identification of the disease is the first step. Determining the level and severity of the disease is the next. This is usually achieved with two simple, non-invasive tests. In one, we compare the pressure in the arm versus the ankle, allowing us to calculate the ABI (ankle-brachial index). Also important are pulse-volume recordings, enabling us to look at the pressures through the different segments of the arterial tree. (The equipment to make these measurements should be available in every podiatrist’s office.)
If the results warrant further investigation, an arteriogram may be performed. In this study, a dye is inserted into the blood stream, providing us with a picture of the vessels themselves, a road map of sorts. This gives the physician specific details about the size and location of the clogs, the kind of information necessary for surgical intervention.
The treatment of peripheral arterial disease is time dependent. The more severe the disease, the more aggressive the treatment required. If significant clogging of the arteries is discovered, surgical intervention is generally required. Vascular surgeons have many advanced technologies at their disposal, allowing them to remove the blockage or place a stent in the vessel to restore blood flow. The best part is this is often performed minimally invasively, ie through a tiny opening. Replacing entirely a diseased blood vessel is sometimes necessary (a by-pass), but the trauma is much greater and healing more difficult.
When caught early, PAD can be treated with a planned, supervised exercise program, obviously a healthier treatment option than most, with the potential for great dividends. Engaging in such a program properly and for sufficient duration is difficult. Many fail but can potentially lead to the growth of new vessels, a process termed collateral circulation. Pharmacologic efforts have not proven to be effective, although reducing the risk of stroke is important.
We need to do a better job, as a culture, of identifying the people who are suffering from this silent killer. Primary care providers need to screen their patients for signs of peripheral arterial disease more consistently. This should start with a quick foot inspection. By identifying those individuals with vessel disease earlier, many amputations can be prevented. Just ask those health care workers that are part of limb salvage efforts: “Save a limb, save a life,” This is our mantra and vigilance is the order of the day.
Editor’s note: Dr. Conway McLean is a physician practicing foot and ankle medicine in the Upper Peninsula, with a move of his Marquette office to the downtown area. McLean has lectured internationally on wound care and surgery, being double board certified in surgery, and also in wound care. He has a sub-specialty in foot-ankle orthotics. Dr. McLean welcomes questions or comments at firstname.lastname@example.org.