The Peripheral Vascular System, PAD and Atherosclerosis

Every year in the United States more than 70,000 individuals unfortunately must undergo an amputation, and it’s not as a result of an accident or war or any form of physical activity. These people lose a limb or toes as a result of disease – atherosclerosis. In this case though, the arteries that are clogged are away from the heart and brain and are in the peripheral vascular system. Peripheral vascular disease (PVD) or peripheral arterial disease (PAD) is a largely preventable disease too.

What is Atherosclerosis?

The two root words that comprise atherosclerosis are “ather” for vessel and “sclerosis” for blocked or closed as a result of scarring. Atherosclerosis is sometimes confused with arteriosclerosis. In fact, the terms are used interchangeably by some though technically they are not the same. Arteriosclerosis is an umbrella term that means artery stiffening for whatever reason and is sometimes called “hardening of the arteries”. The artery walls thicken and get stiff, and it’s usually due to damage from years of high blood pressure. Atherosclerosis is actually a form of arteriosclerosis.[1]

Atherosclerosis is a condition in which the arteries harden specifically due to plaque buildup. It occurs when the cells in the arterial wall undergo fatty degeneration. Fatty degeneration refers to fat globules that accumulate in the cells as cholesterol or plaque is deposited on the walls of the arteries. The arteries then stiffen as the plaque builds up.

There are several types of atherosclerosis, and the symptoms of each type are dependent upon the vessels that are blocked or plugged. As a result, you have:

  • Coronary vessels blocked leading to angina or heart attack
  • Cerebral vessels blocked producing stroke
  • Renal vessels clogged resulting in renal failure
  • Peripheral arteries blocked producing limb ischemia – lack of blood or bloodlessness in the limbs[2]

Peripheral arterial disease is atherosclerosis that is affecting the extremities like the arms and legs. Peripheral arterial disease (PAD) is also associated with the progression of coronary atherosclerosis.[3]

Developing Atherosclerosis

The development of atherosclerosis often precedes the onset of diabetes.  It begins with the deposition of cholesterol in the arteries which is followed by fatty streaks lining the arteries creating yellow streaks on the intima – the innermost lining of the arteries. As the disease progresses there is scarring and calcifying. The result is an irregular narrowing inside of the arteries. Eventually, this leads to a blockage of the blood vessel.

If the blood circulation is poor for a period of time, the worst case scenario develops. The tissue in the legs and feet dies due to lack of nutrients and oxygen.  When the tissue dies and becomes infected with bacteria, it is called gangrene. If medications are unable to reverse this process, there is only one solution. To prevent the gangrene from spreading further, the doctor will decide it is necessary to cut the diseased tissue out or off. This often means the amputation of all or parts of the infected limb.

Who is at Risk?

There are a number of known risk factors for developing atherosclerosis. Diabetes is a major factor, but it is not the only one. Additional risk factors include the following:

  • Age – the older the individual, the greater the risk
  • Gender – males slightly more than females
  • Race – African Americans have higher incidence rates. They have a risk that is higher by as much as 2 times compared to other races – with or without diabetes[4]
  • A concentration of cholesterol
  • High blood pressure
  • Smoking
  • A family history of atherosclerosis (genetics)
  • Obesity

Symptoms

The symptoms vary according to the stage of PAD since it is a progressive disease. These are the most common symptoms:

  • Intermittent claudication – A cramping, tightness or pain in one or both legs that occurs when you walk or exercise[5]
  • Cold feet
  • Pain in the legs even while resting
  • Shiny skin
  • Thickened toenails
  • Loss of hair on the feet
  • A difficult time with wounds healing

When you notice symptoms, it’s important to consult your doctor right away. Failure to do so will increase the likelihood of more serious problems developing, including the loss of mobility, feet or legs, and even death. Research indicates that those with PAD whose functional performance is decreasing are at higher risk for both mobility loss and death.[6]

Evaluating the Symptoms

Symptoms of atherosclerosis or PAD are evaluated in several ways. The doctor may examine the foot and ankle using his or her fingers or a Doppler machine to check for blood circulation or blood pressure. The instrument is more sensitive than hands and has an attached microphone. In addition, the physician will measure and compare the blood pressure at your ankles and arms.

If there are questions or doubts, the doctor will arrange for more complicated and specialized tests to be performed by a vascular surgery specialist. These will not be done in an office but in the imagining department of a hospital or clinic. The most common type of tests ordered are:

  • An ultrasound
  • A cat scan (CT)
  • Arteriogram – x-ray of arteries using an injection of “contrast” dye

If the diagnosis is peripheral vascular damage or PAD, you will need to make decisions about the next step. These will be based on the extent of the disease progression.

Treatment

If you have wounds or ulcers on your extremities that won’t heal due to lack of blood circulation, antibiotics may help. In the early stages of the disease, you may improve circulation through:

  • Exercise
  • Drugs
  • Surgery to open the blocked blood vessels ( arterial bypass surgery, laser angioplasty, balloon angioplasty or an atherectomy)

When the disease has progressed to a certain point and blood circulation cannot be restored to the limbs, the only solution may be amputation. Though an extreme solution, it is sometimes the only solution to save the patient’s life. It is not uncommon for diabetics to lose a limb or toes. The need for amputation is 5 to 10 times higher for a diabetic than it is for someone who is not diabetic. Contributory facts include decreased resistance to infection and sensory neuropathy.

The best treatment, however, is always prevention. Managing your diabetes can prevent the need for such radical treatment.

References

[1] Marcovitch, H (2006). Black’s Medical Dictionary 41st edition. Lantham, Maryland: Scarecrow Press.

[2] Levin, ME; and Pfeiffer, MA (editors) (2009). The Uncomplicated Guide to Diabetes Complications, 3rd ed. Alexandria, VA: ADA.

[3] Hussein, AA; Uno, K; Wolski, K; Kapadia, S; Schoenhagen, P; Tuzcu, EM;. Nissen, SE; and Nicholls, SJ (2011). “Peripheral Arterial Disease and Progression of Coronary Atherosclerosis.” J American College Cardiology Foundation, 57:1220-1225.

[4] Norgren, L; Hiatt,WR; Dormandy, JA; Nehler, MR; Harris, KA; and Fowkes. FGR (2007). “Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II).” European J Vascular and Endovascular Surgery, 33 (S1):S1-S70.

[5] American Diabetes Association (2009). Type 2 Diabetes. Your Healthy Living Guide. Alexandria, VA: ADA.

[6] McDermott, MM; Liu, K; Ferrucci, L; Tian, L; Guralnik, JM; Liao, Y; and Criqui, MH (2011). “Decline in Functional Performance Predicts Later Increased Mobility Loss and Mortality in Peripheral Arterial Disease.” J Am Coll Cardiology, 57:962-970

[7] This article was originally published July 12, 2012 and last revision and update of it was 9/10/2015.