AUTHOR AND EDITOR INFORMATION

Section 1 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

INTRODUCTION

Section 2 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Background

Claudication, which is defined as reproducible ischemic muscle pain, is one of the most common manifestations of peripheral vascular disease caused by atherosclerosis. Claudication occurs during physical activity and is relieved after a short rest. Pain develops because of inadequate blood flow.

Pathophysiology

Single or multiple arterial stenoses produce impaired hemodynamics at the tissue level in patients with peripheral arterial occlusive disease (PAOD). Arterial stenoses lead to alterations in the distal pressures available to affected muscle groups and to blood flow.

Under resting conditions, normal blood flow to extremity muscle groups averages 300-400 mm/min. Once exercise begins, blood flow increases up to 10-fold owing to the increase in cardiac output and compensatory vasodilation at the tissue level. When exercise ceases, blood flow returns to normal within minutes.

In patients with PAOD, resting blood flow is similar to that of a healthy person. However, during exercise, blood flow cannot maximally increase in muscle tissue because of proximal arterial stenoses. When the metabolic demands of the muscle exceed blood flow, claudication symptoms ensue. At the same time, a longer recovery period is required for blood flow to return to baseline once exercise is terminated.

Similar abnormal alterations occur in distal perfusion pressure in affected extremities. In normal extremities, the mean blood pressure drop from the heart to the ankles is no more than a few millimeters of mercury. In fact, as pressure travels distally, the measured systolic pressure actually increases because of the higher resistance encountered in smaller-diameter vessels.

At baseline, a healthy person may have a higher measured ankle pressure than arm pressure. When exercise begins, no change in measured blood pressure occurs in the healthy extremity.

In the atherosclerotic limb, each stenotic segment acts to reduce the pressure head experienced by distal muscle groups. Correspondingly, at rest, the measured blood pressure at the ankle is less than that of a healthy person. Once physical activity starts, the reduction in pressure produced by the atherosclerotic lesion becomes more significant and the distal pressure is greatly diminished.

The phenomenon of increased blood flow causing decreased pressure distally to an area of stenosis is a matter of physics. Poiseuille calculated energy losses across areas of resistance with varying flow rates by using the following equation, in which Q is flow, v is viscosity, L is the length of the stenotic area, r is the radius of the open area within the stenosis, and k is constant:

Resistance = pressure = Q8vL/kr4

Applying this equation, the pressure gradient is directly proportional to the flow and length of stenosis and inversely proportional to the fourth power of the radius.

Therefore, while increasing the rate of flow directly increases the pressure gradient at any given radius, these effects are much less marked than those due to changes in the radius of the stenosis.

As the radius is raised to the fourth power, it has the most dramatic impact on a pressure gradient across a lesion. This impact is additive when 2 or more occlusive lesions are located sequentially within the same artery.

Frequency

United States

Atherosclerosis affects up to 10% of the Western population older than 65 years. With the elderly population expected to increase 22% by the year 2040, atherosclerosis is expected to have a huge financial impact on medicine. When claudication is used as an indicator, estimates are that 2% of the population aged 40-60 years and 6% older than 70 years are affected.

Mortality/Morbidity

The most feared consequence is severe limb-threatening ischemia leading to amputation. However, studies of large patient groups with claudication reveal that amputation is uncommon. Boyd prospectively followed 1440 patients with intermittent claudication for as long as 10 years and reported that only 12.2% required amputation. In the Framingham study, only 1.6% of patients with claudication reached the amputation stage after 8.3 years of follow-up.

• Limb amputation largely depends on the number and severity of cardiovascular risk factors (ie, smoking, hypertension, diabetes). Continued smoking has been identified as the most consistent adverse risk factor associated with the progression of PAOD. Other factors are the severity of disease at the time of the initial patient encounter and, in some studies, the presence of diabetes.
• As with most patients with vascular disease, survival is less than that of age-matched control groups. Coronary artery disease with a subsequent myocardial event is the major contributor to outcome. Predicted mortality rates for patients with claudication at 5, 10, and 15 years of follow-up are approximately 30%, 50%, and 70%, respectively.

Race

• PAOD has no racial predilection.

Sex

• Intermittent claudication most commonly manifests in men older than 50 years.
• Although younger patients may present with symptoms consistent with intermittent claudication, other etiologies of leg pain and claudication (eg, popliteal entrapment syndrome) must be strongly considered.

CLINICAL

Section 3 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

History

Intermittent claudication typically causes pain that occurs with physical activity. Determining how much physical activity is needed before the onset of pain is crucial.

• Typically, vascular surgeons relate the onset of pain to a particular walking distance in terms of street blocks (eg, 2-block claudication). This helps to quantify patients with some standard measure of walking distance before and after therapy.
• Other important aspects of claudication pain are that the pain is reproducible within the same muscle groups and that it ceases with a resting period of 2-5 minutes.
• Location of the pain is determined by the anatomical location of the arterial lesions. PAOD is most common with the distal superficial femoral artery (located just above the knee joint), which corresponds to claudication in the calf muscle area (the muscle group just distal to the arterial disease).
• When atherosclerosis is distributed throughout the aortoiliac area, thigh and buttock muscle claudication predominates.
• The perceived significance of claudication is variable. Most patients appear to accept a decrease in walking distance as a normal part of aging. Investigators report that 50-90% of patients with definite intermittent claudication do not report this symptom to their physician.
• Atherosclerosis is a systemic disease process. Patients who present with claudication due to PAOD can be expected to have atherosclerosis elsewhere. A full assessment of the patient's risk factors for vascular disease should be performed.
• The risk factors for PAOD are the same as those for coronary artery disease or cerebrovascular disease and include diabetes, hypertension, hyperlipidemia, family history, sedentary lifestyle, and tobacco use.
• Smoking is the greatest of all the cardiovascular risk factors. The mechanism by which smoking causes or accentuates atherosclerosis is unknown. What is known is that the degree of damage is directly related to the amount of tobacco used. Counseling patients on the importance of smoking cessation is paramount in PAOD management.

Physical

Essential to the physical examination of a patient with claudication is a complete lower extremity evaluation and pulse examination, including measuring segmental pressures (see Image 1). Atrophy of calf muscles, loss of extremity hair, and thickened toenails are clues to underlying PAOD.

• Palpation of pulses should be attempted from the abdominal aorta to the foot, with auscultation for bruits in the abdominal and pelvic regions. This can be difficult in a patient who is obese, in whom palpable pulses may be hidden under a deep subcutaneous layer.
• Except in the rare case of a congenital absence of a pulse (eg, persistent sciatic artery), the absence of a pulse signifies arterial obstruction proximal to the area palpated. For example, if no femoral artery pulse is palpated, significant PAOD is present in the aortoiliac distribution. The same can be said if no palpable popliteal artery pulse is present because of existing superficial femoral artery occlusive disease.
• Patients who report intermittent claudication and have palpable pulses can present a clinical dilemma.
• • If the history is consistent with typical claudication symptoms, the clinician can have the patient walk around the office (or perform toe raises) until the symptoms are reproduced and then palpate for pulses.
  • The exercise should cause the atherosclerotic lesion to become significant and should diminish the strength of the pulses distal to the lesion.
• When palpable pulses are not present, further assessment of the circulation can be made with a handheld Doppler device.
• • An audible Doppler signal assures the clinician that some blood flow is perfusing the extremity.
  • If no Doppler signals can be heard, a vascular surgeon should be immediately consulted.
• Pressure measurements can be performed to gain objective data on the circulatory status.
• • To obtain an accurate pressure reading, (1) place the pneumatic cuff around the ankle, (2) position the Doppler probe over the dorsalis pedis or posterior tibial artery, and (3) inflate the cuff to a reading above the systolic pressure and deflate. The systolic tone at the ankle vessel is the pressure recorded.
  • A healthy person has no pressure drop from the heart to the ankle. In fact, the pressure at the ankle may be 10-20 mm Hg higher due to the augmentation of the pressure wave with travel distally.
  • In patients with claudication, the measured pressure is diminished to some extent, depending on the severity of PAOD.
• A useful tool in assessing a patient with claudication is the ankle-brachial index (ABI), which is calculated as the ratio of systolic blood pressure at the ankle to the arm.
• • Determining the ABI provides an assessment of the impact that the PAOD is having on the patient. A normal ABI is 0.9-1.1. However, any patient with an ABI less than 0.9, by definition, has some degree of PAOD. The ABI decreases with worsening PAOD.
  • One area of inaccuracy with the ABI is in patients with diabetes who have PAOD. Peripheral vessels in patients with diabetes may have extensive medial layer calcinosis, rendering the vessel resistant to compression by the pneumatic cuff. These patients should be referred to a vascular laboratory for further evaluation.

DIFFERENTIALS

Section 4 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Other Problems to be Considered

Some disease processes mimic claudication symptoms and must be excluded. They include the following:

• Osteoarthritis: This is associated with arthritic pain that is variable from day to day and may be aggravated by certain weather patterns or movements. Rest does not relieve pain.
• Venous disease: Described as a dull, aching pain that typically occurs at the end of the day or after prolonged standing, venous disease is not exacerbated by exercise.
• Neurospinal disease: Pain occurs in the morning and is not relieved by short resting periods. Neurospinal pain is frequently relieved by leaning forward against a solid surface or by sitting.
• Chronic compartment syndrome: This is rare. It is usually observed in runners and other athletes with large, developed calf muscles. Muscles swell during activity, leading to increased compartment pressure and decreased venous return. Consistent with claudication pain, this pain occurs with exercise and is relieved with rest. However, the type of exercise is at a more strenuous level and the recovery period is prolonged.
• Popliteal entrapment syndrome: This syndrome is similar to intermittent claudication but is usually observed in active young people. The syndrome is caused by various abnormal anatomical configurations of the insertion of the medial gastrocnemius muscle head, which causes compression of the popliteal artery. Upon physical examination, tibial pulses may disappear when the knee is at full extension. Pain is aggravated with walking but not with running because knee extension is not as severe with running.
• Reflex sympathetic dystrophy or minor causalgia: This is characteristically described as a burning pain. The superficial pain is often distributed along a somatic nerve and is often related to a past trauma in the extremity.
• Diabetic neuropathy: Pain is due to a peripheral neuritis. Differentiation from intermittent claudication can be difficult because of accompanying skin discoloration and diminished pulses. An extensive neurologic evaluation is essential.
• Venous thrombosis: Swelling and leg pain occur with walking. Pain is relieved by extremity elevation, which distinguishes this entity from arterial insufficiency.

WORKUP

Section 5 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Lab Studies

• A laboratory workup is only helpful for identifying accompanying silent alterations in renal function and elevated lipid profiles.

Imaging Studies

• Angiography still remains the criterion standard arterial imaging study used in the diagnosis of PAOD (see Image 2). However, this test is usually reserved for when an intervention (either endovascular or traditional open surgery) is planned.
• Magnetic resonance angiography (MRA) is useful for imaging large and small vessels. Although MRA was initially felt to provide inadequate images, this is no longer the case. With improved imaging capabilities, MRA can be used to not only diagnose but to help plan the type of indicated intervention.
• Computerized tomographic angiography is another modality used to image arterial disease. Unfortunately, the study still requires a large amount of contrast media and requires an upgraded CT scanner to reconstruct helpful images.
• Duplex ultrasonography is a method of evaluating the status of a patient’s vascular disease. Duplex scanning has the advantage of being noninvasive and requiring no contrast media. Unfortunately, duplex scanning is very technician dependent. 

Other Tests

• See Physical.

TREATMENT

Section 6 of 11  

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• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Medical Care

Treatment of claudication is medical, with surgery reserved for severe cases.

• The goal of medical management is to impede the progression of PAOD.
• • In patients who smoke, the most expedient way to impede the progress of PAOD is to stop tobacco use.
  • Extensive evidence indicates that smoking cessation improves the prognosis.
  • Improved walking distance and ankle pressure have been attributed to smoking cessation.
• Exercise plays a vital role in the treatment of claudication.
• • Patients reduce their daily walking because of claudication pain and fear of further damage. This leads to an increasingly sedentary lifestyle that is even more detrimental.
  • Regular walking programs result in substantial improvement in most patients with claudication. Improvements have ranged from 80-234% in controlled studies.
  • A daily walking program of 45-60 minutes is recommended. The patient is instructed to walk until claudication pain occurs, rest until the pain subsides, and repeat the cycle.
  • While the exact mechanism for improvement in walking distance with exercise remains unknown, regular exercise is thought to condition muscles to work more efficiently (more extraction of blood) and increase collateral vessel formation.
• Additional medical treatment includes control of the lipid profile, diabetes, and hypertension.

Surgical Care

Patients with limb-threatening ischemia or lifestyle-limiting claudication are referred to a vascular surgeon. Only then does evaluation warrant an arteriogram.

Consultations

• Vascular surgeon

MEDICATION

Section 7 of 11  

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• Multimedia
• References

Daily aspirin is recommended for overall cardiovascular care. While standard dosages range from 81-325 mg/d, no consensus has been reached on the most effective dose.

Pentoxifylline (Trental) shows promise. Numerous randomized trials have documented modest improvements in walking distance when compared with placebo treatment groups. Treatment can take 2-3 months to produce noticeable results.

The use of clopidogrel bisulfate (Plavix) and enoxaparin sodium (Lovenox) in the treatment of this entity is increasing; however, further research is needed to establish clinical efficacy.

Drug Category: Antiplatelet Agents

Decrease overall risk of cardiovascular disease from myocardial infarction and stroke. Also improve walking distance by enhancing circulation.

Drug Category: Antilipemic Agents

These agents are beneficial in lowering blood cholesterol profiles, which may reduce the rate of first major vascular events.

FOLLOW-UP

Section 8 of 11  

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• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Further Outpatient Care

• Patients should be seen every 4-6 months to assess the effects of medical therapy. Review changes in walking distance, smoking habits, eating habits, and exercise performance.
• Control hypertension and diabetes if necessary. A repeat pulse examination and ABI complete the follow-up evaluation.
• Patients with worsening symptoms may require intervention and referral to a vascular surgeon.

Complications

• The most feared consequence is severe limb-threatening ischemia leading to amputation. However, studies of large patient groups with claudication reveal that amputation is uncommon.
• • Boyd prospectively followed 1440 patients with intermittent claudication for as long as 10 years and reported that only 12.2% required amputation.
  • In the Framingham study, only 1.6% of patients with claudication reached the amputation stage after 8.3 years of follow-up.

Prognosis

• Whether a patient progresses to limb amputation largely depends on the number and severity of cardiovascular risk factors (ie, smoking, hypertension, diabetes).
• Continued smoking has been identified as the most consistent adverse risk factor associated with the progression of the disease.
• Other factors are the severity of disease at the time of the initial patient encounter and, in some studies, the presence of diabetes.
• As with most patients with vascular disease, survival is less than that of age-matched control groups. Coronary artery disease, with a subsequent myocardial event, is the major contributor to outcome.
• Predicted mortality rates for patients with claudication at 5, 10, and 15 years of follow-up are approximately 30%, 50%, and 70%, respectively.

Patient Education

• For excellent patient education resources, visit eMedicine's Circulatory Problems Center and Cholesterol Center. Also, see eMedicine's patient education articles Peripheral Vascular Disease, High Cholesterol, and Cholesterol FAQs.

MISCELLANEOUS

Section 9 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Medical/Legal Pitfalls

• Misdiagnosis for intermittent claudication rarely leads directly to limb loss. However, make early referrals to a vascular surgeon to decrease the likelihood of any legal action.

MULTIMEDIA

Section 10 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Media file 1:  Peripheral arterial occlusive disease. Measuring segmental pressures.
	View Full Size Image
Media type:  Photo

Media file 2:  Peripheral arterial occlusive disease. This angiogram shows a superficial femoral artery occlusion on one side (with reconstitution of the suprageniculate popliteal artery) and superficial femoral artery stenosis on the other side. This is the most common area for peripheral vascular disease.
	View Full Size Image
Media type:  Photo

REFERENCES

Section 11 of 11

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

1. Randomized trial of the effects of cholesterol-lowering with simvastatin on peripheral vascular and other major vascular outcomes in 20,536 people with peripheral arterial disease and other high-risk conditions. J Vasc Surg. Apr 2007;45(4):645-654; discussion 653-4. [Medline].
2. Boyd AM. The natural course of arteriosclerosis of the lower extremities. Angiology. 1960;11:10.
3. Cassar K, Bachoo P, Ford I, et al. Platelet activation is increased in peripheral arterial disease. J Vasc Surg. Jul 2003;38(1):99-103. [Medline].
4. Clifford PC, Davies PW, Hayne JA, Baird RN. Intermittent claudication: is a supervised exercise class worth while?. Br Med J. Jun 21 1980;280(6230):1503-5. [Medline].
5. Collins TC, Petersen NJ, Suarez-Almazor M, Ashton CM. The prevalence of peripheral arterial disease in a racially diverse population. Arch Intern Med. Jun 23 2003;163(12):1469-74. [Medline].
6. Couch NP. On the arterial consequences of smoking. J Vasc Surg. May 1986;3(5):807-12. [Medline].
7. Cronenwett JL, Warner KG, Zelenock GB, et al. Intermittent claudication. Current results of nonoperative management. Arch Surg. Apr 1984;119(4):430-6. [Medline].
8. Ekroth R, Dahllof AG, Gundevall B, et al. Physical training of patients with intermittent claudication: indications, methods, and results. Surgery. Nov 1978;84(5):640-3. [Medline].
9. Green RM, McNamara J. The effects of pentoxifylline on patients with intermittent claudication. J Vasc Surg. Feb 1988;7(2):356-62. [Medline].
10. Hughson WG, Mann JI, Garrod A. Intermittent claudication: prevalence and risk factors. Br Med J. May 27 1978;1(6124):1379-81. [Medline].
11. Jonason T, Ringqvist I. Factors of prognostic importance for subsequent rest pain in patients with intermittent claudication. Acta Med Scand. 1985;218(1):27-33. [Medline].
12. Kannel WB, McGee DL. Update on some epidemiologic features of intermittent claudication: the Framingham Study. J Am Geriatr Soc. Jan 1985;33(1):13-8. [Medline].
13. Kannel WB, Skinner JJ, Schwartz MJ, Shurtleff D. Intermittent claudication. Incidence in the Framingham Study. Circulation. May 1970;41(5):875-83. [Medline].
14. Porter JM, Cutler BS, Lee BY, et al. Pentoxifylline efficacy in the treatment of intermittent claudication: multicenter controlled double-blind trial with objective assessment of chronic occlusive arterial disease patients. Am Heart J. Jul 1982;104(1):66-72. [Medline].
15. Reid DD, Brett GZ, Hamilton PJ, et al. Cardiorespiratory disease and diabetes among middle-aged male Civil Servants. A study of screening and intervention. Lancet. Mar 23 1974;1(7856):469-73. [Medline].
16. Rosenbloom MS, Flanigan DP, Schuler JJ, et al. Risk factors affecting the natural history of intermittent claudication. Arch Surg. Jul 1988;123(7):867-70. [Medline].
17. Vogt MT, Wolfson SK, Kuller LH. Lower extremity arterial disease and the aging process: a review. J Clin Epidemiol. May 1992;45(5):529-42. [Medline].
18. Walsh DB, Gilbertson JJ, Zwolak RM, et al. The natural history of superficial femoral artery stenoses. J Vasc Surg. Sep 1991;14(3):299-304. [Medline].

Article Last Updated: Jan 2, 2008