peripheral circulation

When we as foot specialists examine a foot, we break it down into four systems: dermatological, orthopedic, neurological and vascular. The vascular or circulation system is further broken down into arterial blood flow into the foot and venous which is blood flow away from the foot back to the heart.

Of the four systems, peripheral circulation problems are potentially the most damaging to the foot. Lets face it, without proper blood flow to the foot or impaired circulation away from the foot the tissues of the foot will suffer and in some cases die (gangrene).

Unfortunately, as we age our peripheral circulation to our feet does become impaired. The degree of impairment will vary from person to person with factors such as genetics, life style (smoking, poor diet, lack of exercise), and other disease states (diabetes, hypertension,) all contributing to a decreased blood flow to and from the foot.

When the foot is examined in regards to peripheral circulation we note the following:

• ability to feel pulses and the strength of those pulses
• color and texture of the skin
• hair distribution as loss of hair can but not always signal a loss of circulation to the foot
• rashes
• ulcers
• venous patterns and venous enlargement
• edema (swelling)
• temperature decreases
• temperature differences between the two feet. In general, one cold foot is suggestive of poor circulation, two cold feet may be indicative of anxiety, neurological or a cold environment.

patient complaints that may suggest poor peripheral circulation

• A change in a patient’s recent history can give us a clue to circulatory impairment. If a patient complains of rest pain meaning their feet and legs will hurt at night, but find that if they put their feet in a dependant position (sitting), or even standing, the pain subsides that is highly suggestive of circulatory problems.
• People who complain of walking a few blocks and experiencing calf pain, finding that if they stop and rest the pain goes away, only to return when they walk about the same distance is highly suggestive of vascular problems.
• Changes in color of the feet when in a dependent position compared to when the feet are elevated.
• Sores on the feet that do not seem to heal is a normal period of time.
• Feet and ankles that appear normal in the morning but progressively swell during the course of the day may be exhibiting poor venous flow. Keep in mind that there is varying degrees of swelling and not all swelling is indicative of serious disease, however, on the other hand if one foot is constantly swollen then circulatory compromise has to be ruled out.

what is atherosclerosis

The most common cause of poor blood flow into the foot is atherosclerosis or hardening of the arteries. This is a progressive degenerative process characterized by the deposition of fatty substances inside the wall of the artery along with a fibrous thickening of the artery wall resulting in a diminished ability of blood to flow down to the foot.

Below is a diagram of the arterial flow into the foot.

This condition in most people will go undiagnosed until the condition becomes symptomatic. When the initial symptoms of intermittent claudication (pain in the calf after walking a short distance, although to a lesser extent the thighs and buttocks) presents, there is already significant disease present. What is essentially happening, due to blockages in the blood flow to the feet, there is a mismatch between the oxygen supply being supplied to the extremities and the metabolic demands of the muscles of the feet and lower legs upon exertion. Simply stated, when muscles are working, they need fresh oxygen to supply them. Any reduction in this oxygen supply to a muscle will cause pain (claudication).

This condition occurs predominately among men between the ages of 50 and 70 years and usually starts after age 60 in women. Race and ethnic background also play a role as African Americans have a higher incidence of peripheral arterial disease (PAD) than non-African Americans. Studies have also shown that Hispanics present with more advanced lower extremity vascular disease and have worse outcomes, which includes a higher amputation rate after revascularization, than non-Hispanic whites. (Lower Extremity Review, March 2013). An estimated 8-12 million Americans have this condition. Fifty percent of people with PAD (peripheral arterial disease) are asymptomatic and usually go undiagnosed.

Major causes of atherosclerosis include:

• diabetes, which affects both the major blood vessels bringing blood into the foot and the smaller vessels, which actually supply each area of the foot.
• Hypertension or high blood pressure can also cause damage to the arteries of the foot and leg and over time diminish blood flow to the feet. It is also worth mentioning that some anti-hypertensive medicine will also adversely affect the feet in that they can cause swelling and discoloration of the extremities.
• Smoking, however, may be the worst cause of damage to the arteries that bring blood to the feet (as well as the heart, brain and kidneys). Smoke from tobacco directly damages the inside of the arteries.

Abnormal causes of atherosclerosis

Although atherosclerosis is generally associated with middle age and elderly individuals, there are instances where young people are affected.

A 17 year-old Irish dancer developed discomfort in her toes as well as discoloration and swelling over a one year period. She was an otherwise healthy individual, not taking any medication. An MRA (magnetic image angiogram) was performed and revealed fibrotic bands of the dorsalis pedis artery which is the artery on top of the foot that runs from the ankle all the way down to the toes.

An ultrasound was then performed that found the fibrous bands were impinging flow of blood through the dorsalis pedis artery when the foot was plantarflexed (pointed downward). Essentially her circulation was being cut off.

Surgery was performed to resect the bands and bounding pulses returned to her feet.

The lesson learned here is that even young people can develop vascular compromise. The majority of these cases are usually from external damage to the arteries through overuse injuries.1

treatment of atherosclerosis

There are a few different treatments for arteriosclerosis in the lower extremity and treatment is based on a number of factors including the degree of blockage either by occlusion (calcified plaque) or by stenosis (narrowing of the artery), the age of the patient, their general overall health, etc.

• As of this writing (April,2008) walking is considered the primary treatment in treating arteriosclerosis in mild to moderate cases. In fact walking works better than oral medication. However, we are talking about a daily walking program on a graded treadmill for 30 minutes. Initially, that may be impossible for many, so you need to work up to that number. This should be a supervised program and you should have clearance from you doctor. Exercise on a regimented, physician supervised program can reduce the symptoms of intermittent claudication in as little as 6 months in many individuals. The problem here is that many people would rather pop a pill daily than to go out and get some exercise, but statistically it has been shown that walking is far superior to medication in this situation. (Vascular Medicine and Intervention2, Holy Name Hospital Interventional Institute, April 2008).
• Medications used for peripheral arterial disease include Cilostazol which increases blood flow by dilating (opening up) arteries and Pentoxifylline which works by making red blood cells more pliable so they can "squeeze" through narrow arteries.

  Below is a picture of very poor circulation into the foot. Notice how pale, thin and shiny the skin is along with sores that have developed on the foot.
  
  

  
  
  

• Once a foot has reached this state exercise or medication is no longer going to cure the problem. Either an angioplasty, stent or bypass surgery will be required to bring the foot "back to life". The image below reveals gangrene of the toes which eventually lead to amputation.

The most common cause of poor blood flow out of the foot is varicose veins. This is a very common disorder seen twice as often in women than men and the prevalence increases with age.

Below is a diagram of the venous system in the foot.

symptoms of venous insufficiency (poor venous flow)

• Generally, the patient’s foot and ankle will be normal in appearance in the morning only to swell as the day progresses and return to normal the next morning.
• The common complaint is a feeling of a dull heavy ache that develops after long periods of standing, which is relieved by elevating the leg or by the use of elastic stockings.
• Occasionally symptoms of itching, burning and cramps may also be present.

Increased humidity, obesity and the cyclic premenstrual period may exacerbate the symptoms.

treatment of venous insufficiency

• In simple to moderate cases, compression stockings may relieve the symptoms. They should be applied first thing in the morning before the extremity has started to swell, however in those that require a heavier compression, the stockings can be very difficult to put on and take off and can be very uncomfortable in hot weather.
• Injection of saline and other chemicals may be used to force the veins to collapse, which in itself may not improve return circulation but will make the protruding veins more cosmetically acceptable. This is known as sclerotherapy.
• Surgical "stripping" or removal of the offending varicosed vein.
• Under the category of "folk remedies" there are two ways to minimize simple varicose veins.

  The first is apple cider vinegar. Soak a cheesecloth bandage in apple cider vinegar and use it to wrap the affected area for thirty minutes. Make sure you legs are reclined above the level of your heart. Do this twice a day. Vinegar is believed to encourage varicose veins to contract. Some people also suggest drinking two teaspoons of apple cider vinegar in a cup of warm water after each session.

  The second is bromelain. This collection of enzymes found in pineapples has anti-inflammatory properties believed to inhibit the unattractive swelling around varicose veins. Take 500-1000mg with each meal. Bromelain is available in health food stores.

In more severe cases of venous insufficiency the leg can become chronically swollen and inflamed. The leg is now much more susceptible to ulceration and infection.

Below is a picture of severe venous stasis. Notice the swelling and discoloration of the leg. A complication of this condition is a venous stasis ulcer.

Deep venous thrombosis is also a medical emergency. This is a blood clot that has occurred in a vein in the leg. The classic example is severe tenderness in the calf upon pressing the area with the foot simultaneously being dorsiflexed (foot bent upward); this is known as Homan's sign.

Other symptoms include persistent or unexplained swelling usually in only one lower leg. Additionally, the leg may also be red in color. This should not be confused with intermittent claudication, which generally results in calf pain after walking and no swelling in the foot and ankle.

The diagnosis is usually made with the use of a venogram, and more recently with duplex venous ultrasound. In patients who exhibit shortness of breath, fever, rapid heart beat or dizziness, a pulmonary embolism also has to be ruled out.

Factors that increase the chance of a deep venous thromobus (DVT) consist of:

• injury to the inner wall of the vein
• a hypercoagulable state which means means the blood has a greater tendency to clot. Factors such as smoking, malignancy, use of birth control pills, hormone replacement therapy, congestive heart disease and obesity all can contribute to this problem.
• people who exhibit venous stasis or excessive pooling of blood in the veins around the lower leg are also more prone to forming a DVT. The most common risk factor, however, is a previous history of embolism in the lower extremity.

People with any of the above mentioned conditions which may lead to a DVT should be very careful when contemplating foot or ankle surgery and should make their doctor aware of any of the above problems. Hopefully your surgeon will take a proper history and these problems will become known during the interview.

Most cases of DVT following lower extremity surgery is associated with major orthopedic procedures involving the hip and knee but a blood clot can form after foot and ankle surgery so it is imperative both patient and doctor are aware of the possibility.

Below is a picture of DVT, deep venous thrombosis of the right leg.

This condition requires hospitalization and anticoagulant medication to break up the clot. Without treatment there is a very high incidence of the clot breaking loose and causing a pulmonary embolism, which is a life-threatening situation. This type of clot is also known as (VTE) or venous thromboembolism.

A more common condition with less potential complications is a superficial phlebitis. This is an inflammation of one of the superficial veins such as on top of your foot that forms a clot and inflammation ensues.

This is usually a benign and self-limiting condition. Typically, a patient will present complaining of a painful, red area on the foot or lower leg with a lump underneath the skin. The lump is cord-like in its appearance. They can occur spontaneously or after trauma directly to the area.

Treatment consists of warm compresses and anti-inflammatory medication.

NOTE: there are many more conditions of peripheral circulation that have not been discussed. For example, see my discussion on blue toe syndrome.

Buerger's disease

One vascular problem affecting both the arteries and veins that I would like to mention is a condition known as Buerger's disease or thromboangitis obliterans. I have seen one such case and that was during my residency, but found it to be fascinating.

Buerger's disease is a condition that affects medium sized arteries and veins leading to the hands and feet. It is an inflammation of either the arteries or veins which thus causes a blockage of blood flow usually into the fingers and toes. It is a condition that has a predominance in jewish and asian populations affecting men three times as much as women. The incidence in the United States is estimated to be 12-20 cases per 100,000 population. The disease is most prevalent during the ages of 25-40 years.

No immunologic or toxic basis has been identified as the cause of this condition, but there is a very strong correlation with tobacco use. Tobacco itself has the propensity to thicken the inner lining of blood vessels as well as cause vasoconstriction (clamping down) on vessels further diminishing blood flow.

Thromboangitis obliterans has two stages:

Early Stage- where there is periodic episodes of inflammatory reactions which essentially inflame the internal lining of arteries and veins causing a diminished flow of blood into the fingers and toes and obstruction of veins by thrombosis which does not allow for proper blood flow from the fingers and toes back to the heart.

Late Stage- constriction of arterial flow to the point where ulceration and possibly gangrene set in at the ends of the fingers and toes. Thrombophlebitis of the venous system resulting in medical emergency as well as formation of ulcers along the course of the veins.

Diagnosis is made by taking a thorough history with any admissions of tobacco use. Once this condition is suspected, it can be confirmed through a multitude of vascular testing. This includes doppler studies of the arteries as well as plethysmography which measure blood volume in the fingers and toes. Ultrasound studies measuring venous flow are also performed, as well as nuclear imaging.

Treatment options for Buerger's disease include cessation of smoking, although in the one case I have observed, the patient continued to smoke even as his toes were being amputated one by one. Anticoagulants may be used for any thrombophlebitis that may develop. Anti-inflammatory medication is also used in sub-acute incidences of phlebitis. Vasodilators which attempt to open up vessels for increased blood flow are used in early stages to reduce the vasospastic component of the condition. Lastly, in many cases amputation is necessary if any ulceration becomes grossly infected or if gangrene has set in.

The more serious conditions described above are generally diagnosed with sophisticated testing such as arteriograms and venograms along with dopplers and nuclear imaging. Inspecting the area can give us an idea of the problem but testing confirms them. These conditions are best diagnosed and treated by vascular surgeons, however, the local treatment of any foot manifestation is usually best in the hands of a podiatrist.

1 Foot Claudication with Plantar Flexion as a Result of Dorsalis Pedis Artery Impingement in an Irish DancerSmith BK, Engelbert T, Turnipseed WD, (University of Wisconsin Hospital and Clinics, Madison, WI)

J Vasc Surg 2013 Jul;58(1):212-214

ADDITIONAL REFERENCES

Mayo Clinic

Johns Hopkins Medicine

Cleveland Clinic

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