Although there are several methods to treat PAD, ranging from medication to angioplasty to surgical bypass, the most important form of treatment is a change of lifestyle. This means quitting smoking, eating a healthier diet, and getting more exercise. Yet, the most crucial part of lifestyle is good foot care.
This is the reality for individuals with Peripheral Arterial Disease (PAD). PAD can be described as a chronic, life-altering condition in which a build-up of fatty deposits in the arteries reduces blood flow to the legs and feet. This results in restricted mobility and can lead to the possibility of developing Critical Limb Ischaemia (CLI). CLI can be considered the most severe end of the spectrum regarding PAD. Symptoms of CLI include severe pain or numbness, even while resting. CLI can also lead to ulcers or sores on the legs and feet, and in the most serious cases, it can lead to limb amputation.
Consider a world without mobility. Imagine routine activities such as grocery shopping or attending a family event being a burden. Everyday activities become a struggle. You become weary, weak, and easily tired. Your legs and feet become extremely painful, making it hard to stand or walk.
Overview of Peripheral Arterial Disease (PAD)
At the worst end of the scale, some people with PAD will develop critical limb ischemia. This is defined as ischemic rest pain, arterial leg ulcers or gangrene, often in the setting of diminished pedal pulses and ABI <0.40, <0.50 or <0.60. A patient with CLI has an annual mortality rate of 20-25% and a limb loss rate of 20-35% for the first year after diagnosis. This is clearly a condition which has a heavy burden on the individual and society.
The tough part about intermittent claudication is that once it occurs, it is a sign that something is wrong. People living with PAD have a 4-5 times higher risk of having a heart attack or stroke. Often it’s because the atherosclerosis is not just affecting the arteries in the legs. If this is the case, it is not unusual for a patient to suffer from ‘silent’ myocardial ischemia and be at a high risk of sudden cardiac death. By assessing the location, nature and severity of the intermittent claudication, a physician can make general predictions about the severity and location of the atherosclerosis. This is helpful when patients are at high risk for invasive procedures such as angioplasty or surgical revascularization.
PAD is a condition which develops as arteries supplying the blood to the internal organs, arms and legs become clogged with plaque. It is also known as atherosclerotic occlusive disease of the lower extremities. The earliest and most common symptom of peripheral artery disease (PAD) in the lower extremities is intermittent claudication, a painful cramping in the hip, thigh or calf muscles that occurs during walking or exercise. The location of the pain depends on the location of the narrowed or blocked artery. The pain typically occurs consistently after the same amount of exercise and is relieved by rest. This is a result of reduced blood flow to the affected area. Intermittent claudication is a critical clinical indicator of PAD.
Significance of Foot Care in PAD
It is often said that the foot of the world is the next battleground. Canadians might do well to heed this warning in the light of statistics from the US showing that 82% of amputations in patients with PAD occur in the lower limb and that the 5-year survival rate after amputation is only 25%. It is now established that patients with PAD, whether asymptomatic or symptomatic, have a greatly increased risk of CVD and cerebrovascular events. Patients with intermittent claudication have a 6% per annum risk of non-fatal MI or stroke and a nearly 6% annual mortality rate from CV events. Patients with critical ischemia are at even higher risk with 5-year CV mortality rates of up to 60% and a 50% chance of having a major amputation (most commonly the ipsilateral or contralateral limb) in the same time period. The prognosis of the patient with PAD has thus far only been shown to be getting worse, a study within the UK between the mid-1990s and 2008 showed an increase of 25% in both prevalence and incidence of PAD amongst adults over the age of 40. This is likely due to increased age of the general population and also increases in diabetes and smoking, two conditions known to contribute significantly to the development of PAD. The reason why patients with PAD have such a high burden of systemic atherosclerosis is that PAD is a manifestation of a systemic atherothrombotic process. As such, it is likely that an individual with PAD will have disease affecting other vascular beds and possibly the same limb on the contralateral side, therefore there is an increased importance in treating any foot problems in this group of patients.
Importance of Ulcer Prevention in PAD
It is first important to understand why PAD patients are at such a high risk for developing ulcers. Ulcers form in the skin as a result of tissue breakdown. This tissue breakdown is a result of a lack of oxygen to the area. The lack of oxygen delivery to the skin in PAD patients can be caused by minor trauma. Normally, this trauma would heal without incidence. However, in the PAD patient, there is insufficient blood flow to provide the necessary oxygen and nutrients to repair the injured area. This will result in that particular piece of skin dying and forming an ulcer. The most common location for PAD-related ulcers is the feet and toes. This can be attributed to the fact that the feet are the furthest distance away from the heart and therefore the oftentimes insufficient blood flow to the feet becomes even more compromised.
Extremely critical to the care of the PAD patient, ulcer prevention acts as a means to stave off the beginnings of severe limb ischemia. It is well known that PAD patients have a higher mortality and morbidity rate from cardiovascular events. Recent studies have indicated that PAD patients have a similar mortality rate to that of cancer patients. This finding stresses the importance of aggressive cardiovascular risk factor modification. Preventing ulcers will prevent the downstream effects of severe limb ischemia, which include surgery, possible amputation, and death.
Foot Care for Peripheral Arterial Disease
Avoiding dry or cracked skin is important for someone with peripheral arterial disease, and using lotion after a shower can help prevent this. It is important to dry the area between the toes very carefully and apply powder if necessary. If the skin is dry and flaky, a pumice stone can be used to remove the dead skin, but be careful not to cause skin damage. Keeping toenails trimmed and filing the edges is also important to prevent any damage from occurring. However, it is wise to get this done by a chiropodist as the nails need to be trimmed straight across with no sharp edges. Sharp edges increase the risk of scratching the skin and causing ulcers. Gently removing calluses is also important. A pumice stone can be used for this as well, but do not use medicated pads or try to remove them yourself if you suffer from diabetes.
2.1 Daily Foot Care Routine
Dry gangrene is much less serious; however, it can be a starting point for wet gangrene if it becomes infected. When muscles and other tissues become infected, wet gangrene occurs. Wet gangrene can pose a serious threat of spreading quickly and can be life-threatening. It is critically important to treat gangrene as early as possible to avoid its progression. Therefore, seeing a doctor once gangrenous ulcers are spotted is important. Seeing a podiatrist (foot doctor) on a regular basis is also wise to prevent other serious complications that cannot be treated conservatively. This includes critical limb ischemia, where blood supply to a limb is seriously restricted. This is a serious condition that can be life-threatening, and amputation may be necessary. Haglund’s deformity is a protuberance on the back of the heel bone that can rub against shoes and cause chronic ulcers. Until it is fully treated, it can recur. A podiatrist will check for pulses in the feet and swelling in the ankles. This can help identify specific sites of peripheral arterial disease.
Daily Foot Care Routine
Daily foot care is important in preventing ulcers in PAD patients. A good daily foot care routine can decrease the risk of developing ulcers on the feet and can greatly increase the likelihood of healing if an ulcer does develop. Patients should wash their feet daily with mild soap and warm water. Use a soft washcloth and be sure to dry their feet, especially between the toes. Apply lotion to the top and bottom of the feet; however, it should never be applied between the toes. Lotion helps prevent the skin from drying and cracking. Inspect the feet for any cuts, sores, cracks, or changes in the toenails. Using a mirror placed on the floor can help with seeing the bottoms of the feet. If anything is found, patients should make an appointment to see their podiatrist as soon as possible. An ounce of prevention is worth a pound of cure, and catching any foot problems early can prevent serious complications from developing.
Proper Foot Hygiene
Good foot hygiene involves washing the feet daily. The feet should be washed in warm, soapy water and dried thoroughly, especially between the toes. Allowing the feet to soak is not advised as this can lead to maceration of the skin. The temperature of the water should be tested with the hands as a person with nerve damage may not be able to tell how hot the water is. If the feet are too dry, cracking can occur. A moisturizing cream can be used on the top and bottom of the feet to prevent this from happening, but the areas between the toes should be kept dry. Any excess cream should be wiped off the feet so that dust does not stick to it. If the skin becomes itchy or flaky, it is important not to scratch it as this can lead to breaks in the skin. Over-the-counter remedies for athlete’s foot should only be used after consulting a GP or podiatrist as many are unsuitable for people with poor circulation or diabetes. If breaks in the skin do occur, the feet should be washed and a dry dressing should be applied.
Choosing Appropriate Footwear
The major pitfall is determining the appropriate balance between footwear that is protective and footwear that is offloading. The more severe ischaemic limb with rest pain and/or tissue loss can benefit from an offloading device. This may be a simple felted foam pad with a cut-out hole over the site of the ulcer but may progress to a custom-made irremovable cast or boot. Devices such as these aim to redistribute plantar pressure and prevent direct trauma to the affected area. Offloading is, of course, detrimental to the patient with a marginal ABPI. They already have a reduced blood supply to the limb, and a further decrease in pressure may exacerbate symptoms. These patients should not wear a device that is overly offloading, and if it causes a significant increase in ischemic symptoms, it must be removed immediately. Always remember with these devices, the patient should be regularly monitoring his feet and may benefit from assessment by a medical professional to ensure that the skin has not broken down in any other areas.
Proper footwear is one of the most important strategies in the prevention of ulcers. Constant external trauma from ill-fitting shoes causes up to 80% of foot ulcers. Pressure areas and calluses result from excess friction from footwear that is too tight. Neuropathic feet can be deformed, and the loss of protective sensation makes the patient unaware of the excessive pressure, shearing, and rubbing forces from footwear on certain areas of the foot. The initial foot deformity in PAD is often a flat foot with collapse of the medial longitudinal arch. It is important that footwear supports the arch and does not allow the foot to roll inwards. This can be determined by examining the sole of the shoe; an even sole is inappropriate if the foot has a rocker bottom deformity. Patients with Charcot’s arthropathy or previous foot ulcers should seek advice from a podiatrist or orthotist regarding special custom-made insoles. Depth shoes with a large protective toe box are essential for those with toe deformities or where swelling is a problem. Laced shoes or an adjustable fastening are recommended to hold the foot firmly and prevent excessive movement within the shoe.
Regular Foot Examinations
It should be routine for all individuals with PAD to carefully inspect their feet on a daily basis, paying close attention to the areas between and under the toes and bottoms of the feet. Particular care should be focused on avoiding minor trauma to the feet, including abrasions, cuts, scratches, or blisters. Any minor injuries should be promptly cleaned with soap and water, treated with an antiseptic, covered with a sterile dressing, and monitored carefully until healed. Due to the nature of PAD, minor injuries may take several weeks to heal, during which time it is not uncommon for infection to occur. In the event of swollen, painful, red, or warm feet or legs, the development of an ulcer or infection, seek medical advice immediately from a podiatrist or the individual’s GP. A foot infection should never be taken lightly by someone with PAD. In severe cases, it can be the initial event that results in amputation. Regular input from a podiatrist is recommended for individuals with PAD, as a podiatrist can assist patients in identifying and addressing any existing or potential foot problems at an early stage. For example, the podiatrist may be able to detect weak pulses in the feet, which can be indicative of worsening PAD.
Ulcer Prevention Strategies for Peripheral Arterial Disease
The development of foot ulcers in patients with peripheral arterial disease (PAD) can lead to a downward spiral in foot and leg complications. Pain and discomfort caused by these ulcers can be very debilitating, limiting mobility and making it difficult to carry out simple exercises which would benefit the patient. This lack of mobility has serious implications for the PAD patient as they are already at high risk of cardiovascular complications. In addition, the development of a foot ulcer can often lead to further complications such as infection or amputation. Preventing foot ulcers is therefore a key part of both the treatment and management of PAD. This essay will discuss the importance of ulcer prevention and will outline strategies which patients can employ to prevent ulcer development.
Understanding the Risk Factors for Ulcers
The largest study yet on lower extremity amputations in Europe begins with this sentence: “The strongest predictor of an individual requiring an amputation is a previous history of an amputation.” The cross-sectional study, involving 22 European centres, found that Peripheral Arterial Disease (PAD) was present in the majority of cases: 82% of major amputations and 66% of minor amputations were performed on limbs with PAD. When treating PAD without knowledge of the disease’s full implications for the patient’s mobility, quality of life, and long-term prognosis, prevention of ulceration is the ultimate goal – preventing sores optimizes patients’ well-being and is cost-effective. Ulcers are chronic wounds on the skin of an affected area which fail to heal. In the case of PAD, they are a result of ischemia: the lack of blood supply to the area deprives it of oxygen, nutrients, and the ability to fight off illness. Ischemia in the extremities occurs when fatty deposits in the blood vessels (atherosclerosis) form into a solid core that can disrupt plaque and cause embolisms. High glucose levels, e.g. in diabetes, cause damage to the blood vessel walls and reduce their diameter. Ischemia will essentially ‘open the door’ to injuries which ‘slam shut’, unable to heal. Prevention of the injury occurring is the most effective method of ulcer treatment; famed PAD specialist Dr. Josef Dormandy writes “The best treatment of an ischemic leg ulcer is to never let it occur.”
Maintaining Optimal Blood Flow to the Feet
The microvascular circulation is potentially even more significant in affecting wound healing. This damage is caused by high levels of blood glucose over a long period of time and is not limited to the feet. If the skin is already starved of oxygen and nutrients, any form of damage may lead to an ulcer, as there is no reserve of nutrients to facilitate healing. Tight control of blood glucose is the key to preventing further damage, but unfortunately, this will not improve the circulation. It is for this reason that smokers must stop, as smoking severely affects the microvasculature and increases the likelihood of a poor outcome in patients with diabetes and PAD.
In the previous section, it has been established that PAD leads to a supply problem of oxygen and nutrients to the skin, compromising the healing potential of wounds. It is crucial, therefore, to understand the factors that affect blood supply to the feet. There are two components to blood flow to the feet: the macrovascular (large vessel) and microvascular (small vessel) circulations. Any compromise in blood flow will affect the healing potential of wounds. The macrovascular circulation is affected by atherosclerosis (furring up of the arteries with fatty deposits), the same process that caused the PAD. A high level of cholesterol and fats in the blood, as well as uncontrolled blood pressure, are all exacerbating factors. It is important to ensure that these are well controlled, and it may be prudent to consider using drugs such as aspirin to prevent blood clots.
Managing Blood Sugar Levels
Maintaining the normal range of blood sugar will help in preventing neuropathy and other complications of diabetes from progressing and becoming more severe. This in turn will help to prevent ulcers from developing on the feet. Measures of blood sugar control such as glycosylated hemoglobin or “A1C” should be maintained at less than 7%. This is a hemoglobin blood test that gives an average of what the blood sugar level has been over the past 3 months. High levels of A1C have been linked to increased prevalence of foot sores in patients with diabetes. By preventing the progression of neuropathy and reducing the prevalence of foot sores, patients can avoid the complications that arise as a result of P.A.D. and diabetes.
Due to the fact that neuropathy is more prevalent and more severe in patients with poor blood sugar control, it is crucial for patients with P.A.D. and diabetes to maintain good blood sugar levels in an effort to prevent ulcers. Those patients already using insulin should carefully monitor blood glucose and contact their physician if blood sugar levels consistently exceed the normal range. Patients who do not take insulin or other medications for diabetes may be able to control blood sugar levels through diet and weight management. Establishing an appropriate diet can be complex and challenging, particularly for patients who have to make significant changes in order to manage their diabetes. Patients with diabetes will benefit from a referral to a registered dietitian who can provide individualized diabetic medical nutrition therapy. Regular assessments of body weight can also help to monitor whether a patient’s current eating and exercise habits are contributing to good blood sugar control.
Promoting Wound Healing
Effective and rapid healing of the wounds is the essential ultimate step in the management of foot ulcers. Although the cellular and molecular events that occur in recalcitrant neuropathic and ischemic ulcers after the occurrence of the initial injury are not clearly defined, it is apparent from the differences in appearance and course of these wounds that there are different pathophysiological processes occurring in neuropathic and ischemic ulcers. Akin to the treatment of neuropathic and ischemic ulcers, there are similarities and differences in the methods used to promote wound healing in each type of ulcer. High plantar pressures play a causative role in the development of neuropathic ulcers; therefore, reducing pressure on the neuropathic foot ulcer is a primary concern. The normal strategy to offload a foot ulcer is to apply a total contact cast (TCC). Using a TCC has been shown to be very effective in healing of neuropathic plantar ulcers with a high level of offloading and has been reported to result in complete healing of the ulcer in 4-6 weeks in 77% of cases. Offloading is less remediable in a patient with a Charcot midfoot collapse, and it has been advised that if there is no lateral or dorsal ulceration with the Charcot foot, then immobilization and protection of the foot in a TCC or walker brace until the acute phase has subsided may facilitate healing of the Charcot process and prevent ulceration. However, if there is an ulceration, a customized or off-the-shelf therapeutic shoe or a short leg walking cast is advised with frequent assessments of the foot to monitor for signs of further breakdown. Complete contact is essential to effectively offload the ulcer; therefore, any removable walking irons or devices should be avoided. Unrelieved ischemia will progressively impede the healing of any wound that occurs in the setting of PAD. Therefore, the first step in promoting healing of an ischemic ulcer is an assessment of the arterial supply to the ulcerated limb. The importance of this stage cannot be underestimated since failure to heal the ulcer and any subsequent development of infection in the setting of ischemia could lead to limb loss. An understanding of the natural history of CLI and probability of the patient being an acceptable surgical risk can assist in decisions to proceed with revascularization.
Collaborative Approach to Foot Care and Ulcer Prevention
The most frequent cause of amputation in developed countries is not trauma, but ischaemia related to peripheral arterial disease (PAD) of the lower limb. Critical limb ischaemia (CLI) is a severe form of PAD, which can be defined as the presence of chronic ischaemic rest pain, ulcers or gangrene attributable to objectively proven arterial occlusive disease, which without revascularisation has a high probability of leading to limb amputation. For patients with CLI, the estimated amputation-free survival at 1 year is as low as 70-75%, dropping to 50% at 3 years. Amputation of a limb is a life-changing event that has a profound negative impact on an individual. The mortality rates following major limb amputation are very high with up to 40% of patients with diabetes dying within 1 year. Even if no loss of limb occurs, patients with CLI have a 20-25% risk of cardiovascular events (myocardial infarction, stroke, death) at 1 year, similar to some forms of cancer. CLI can often be painlessly complicated by tissue loss due to the masking of ischaemic symptoms by peripheral sensory neuropathy. Approximately 50% of all CLI patients will have ischaemic skin lesions or ulcers. Healing rates for CLI ulcers are poor, with 1-year rates of limb salvage and survival ranging from 25-56%. Although the level of evidence base in CLI and CLI-related ulcers is low, it is clear that these patients need rapid access to specialized multidisciplinary care if there is to be any chance of altering the natural course of the disease and improving the clinical outcomes.
Role of Healthcare Professionals in Foot Care
A study has shown that nail and callus care by chiropodists can prevent ulceration in certain high-risk patients, supporting the pertinence of regular foot care by healthcare professionals in at-risk patients without current foot lesions. IDEAL suggests that identification of foot lesions not attributed to acute trauma (e.g. blister, abrasion, shallow ulcer) requiring >1 week of treatment is a criterion for referral to specialty care given the potential benefit of early treatment in prevention of chronic wounds and ulceration. Ongoing primary care and monitoring of patients with foot lesions has been shown to reduce the incidence of hospitalization for foot infection and feet-related amputation.
The healthcare professional is a proponent of preventive foot care, especially in high-risk patients with diabetes or advanced PAD. Regular foot examinations by a healthcare professional and primary care clinician help to identify risk factors and early foot lesions. The use of the 10-g monofilament, tuning fork, palpation of pedal pulses, and ankle/brachial index can aid in the assessment of risk and vascular status of the diabetic foot. Identification of predominant risk factors (e.g. foot deformity, peripheral neuropathy) and regular foot assessment can facilitate early referral to a podiatrist or foot-care specialist. Lack of symptoms should not be an inhibition to patient evaluation given the potential benefit of early intervention in high-risk patients. A recent publication has offered a classification system for the high-risk diabetic foot to help standardize assessment and compare populations of patients at risk for ulceration and amputation.
Importance of Patient Education and Self-Care
This theme of education was recently addressed in a research article titled “Development of a Patient Question Prompt Sheet to Enhance Communication with Clinicians”. The authors found that patient involvement in the development of their own questions is an effective tool in increasing patient participation in medical decision-making and question asking to their healthcare providers. This empowerment of the patient through increased involvement in their own disease is part of the process of increasing a patient’s self-efficacy. This is combining the patient’s belief in their own capacity to execute behaviors necessary to achieve specific performance outcomes. Patients with high self-efficacy are more likely to adopt and adhere to given behaviors if they believe it will prevent a negative health outcome. This is precisely what is desired in trying to get neuropathic patients to take better care of their feet in order to prevent a foot ulcer. This can be achieved by setting specific tasks and goals for the patient and ensuring progression by task mastery and efficacy expectation through verbal reinforcement and feedback.
There is a lack of understanding of the importance of regular foot inspection and failed implementation of self-care recommendations by patients. Studies have shown that it is possible to educate patients about the risk of ulceration and how to prevent it, but it requires repetitive sessions and a team-based approach involving the use of written instructions, video/CD ROM, and verbal instruction. Various learning styles should be taken into account, and the education should be tailored to the individual. Patients should be given the goals of what they need to learn, e.g. what is the risk of ulceration, what they need to do daily, and what to look for with each task, and they should be tested on their learning to improve knowledge. It is not only the patient that needs education, but their family and caregivers to provide the support and encouragement at home.
Engaging Support from Family and Caregivers
Specific to PVD and foot care, patients should inform their family and/or caregivers about the diagnosis and the increased risk of foot ulcers. Clarifying the risk to an individual’s mobility, independence, and quality of life can be a powerful motivator to the patient’s family or caregiver. Family members may offer practical assistance with foot inspection, nail cutting, and hygiene or assist in arranging professional podiatry care. Patients who have difficulty managing their own foot care may benefit from professional intervention. This may range from regular chiropody treatment (within the health service or private) to more specialized care for a high-risk foot. Involve soaking the feet and ankles for 15 minutes before applying any cream. This will help eliminate dry skin, which is a common cause of dermatitis. Avoid putting cream between the toes. Cream should be applied to the back, front, and sides of the feet, but avoid the creases of the ankle and sole of the foot. After using foot cream, massage feet and ankles to improve blood flow.
