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 expressed in terms of street blocks (eg, two-block claudication). Using some standard measure of walking distance helps quantify patients’ condition 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.
The location of the pain in patients with peripheral arterial occlusive disease (PAOD) is determined by the anatomic location of the arterial lesions. PAOD is most common in the distal superficial femoral artery (located just above the knee joint), a location that 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 clinician.
Atherosclerosis is a systemic disease process. Accordingly, 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 therefore be performed. The risk factors for PAOD are the same as those for coronary artery disease (CAD) or cerebrovascular disease and include the following:
-
Diabetes
-
Hypertension
-
Hyperlipidemia
-
Family history
-
Sedentary lifestyle
-
Tobacco use
-
Chronic kidney disease
Smoking is the greatest of all the cardiovascular risk factors. The mechanism by which it causes or accentuates atherosclerosis is unknown. What is known is that the degree of damage is directly related to the amount of tobacco used. In a prospective cohort study of 39,825 women without cardiovascular disease, smoking was found to be a potent risk factor for symptomatic peripheral arterial disease, and cessation was found to reduce the risk. [5] Counseling patients on the importance of smoking cessation is paramount in PAOD management.
Low kidney function has been associated with the development of PAOD. In fact, a study conducted in Japan [6] found the prevalence of PAOD to be 17.2% among patients with estimated glomerular filtration rates (GFRs) lower than 60 mL/min/1.73 m2, compared with 7.0% in those with GFRs higher than 60 mL/min/1.73 m2. Advanced chronic kidney disease was found to be an independent risk factor for PAOD.
Physical Examination
Essential to the physical examination of a patient with claudication is a complete lower-extremity evaluation and pulse examination, including measurement of segmental pressures (see the image below). 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 with obese patients, in whom palpable pulses may be hidden under a deep subcutaneous layer.
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. Similarly, if no popliteal artery pulse can be palpated, significant superficial femoral artery occlusive disease exists. The exception is the rare case of a congenital absence of a pulse (eg, persistent sciatic artery).
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 consulted immediately.
Pressure measurements can be performed to gain objective data on the circulatory status. An accurate pressure reading is obtained as follows:
-
Place the pneumatic cuff around the ankle
-
Position the Doppler probe over the dorsalis pedis or the posterior tibial artery
-
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 because of the augmentation of the pressure wave with travel distally. In a patient with claudication, however, the measured pressure at the ankle will be 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 systolic blood pressure in the arm. The ABI can help quantify the presence and severity of disease. A normal ABI is 0.9-1.1. By definition, any patient with an ABI lower than 0.9 has some degree of PAOD. As PAOD worsens, the ABI decreases further.
A 2011 study investigated whether subjects not considered to be at high risk for cardiovascular disease had abnormal ABIs. [7] Cardiovascular risk was determined on the basis of the Framingham Risk Score: 56.3% of the study subjects were at low risk for cardiovascular disease, 25.8% at intermediate risk, and 17.9% at high risk. Only a relatively low percentage (~12%) of participants had a low or intermediate Framingham Risk Score while still having an abnormal ABI. This study demonstrated the close association of cardiovascular disease with PAOD.
The ABI may be a less accurate assessment tool in patients with diabetes who have PAOD. Peripheral vessels in patients with diabetes may have extensive medial-layer calcinosis, which renders the vessel resistant to compression by the pneumatic cuff. These patients should be referred to a vascular laboratory for further evaluation. In this situation, the use of the toe-brachial index (TBI) may be helpful.
Complications
The most feared consequence of PAOD 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. [8] In the Framingham study, only 1.6% of patients with claudication reached the amputation stage after 8.3 years of follow-up.
-
Peripheral arterial occlusive disease. Measuring segmental pressures.
-
Peripheral arterial occlusive disease. Angiogram shows superficial femoral artery occlusion on one side (with reconstitution of suprageniculate popliteal artery) and superficial femoral artery stenosis on other side. This is most common area for peripheral vascular disease.
-
Peripheral arterial occlusive disease. Procedures performed during acute admission for peripheral arterial disease in US from 1996 to 2005. Reprinted from Journal of Vascular Surgery, Vol 49(4), Rowe VL et al, Patterns of treatment for peripheral arterial disease in the United States: 1996-2005, Pages 910-7, Apr 2009, with permission from Elsevier.
Tables
What would you like to print?
- Overview
- Presentation
- DDx
- Workup
- Treatment
- Guidelines
- DFA Guidelines on Management of Peripheral Arterial Disease in Diabetes-Related Foot Disease
- CCS Guidelines on Management of Peripheral Arterial Disease
- SVS/ESVS/WFVS Guidelines on Chronic Limb-Threatening Ischemia
- ESC/ESVS Guidelines on Lower-Extremity Arterial Disease
- AHA/ACC Guideline on Lower-Extremity Peripheral Arterial Disease
- SVS Guidelines on Atherosclerotic Occlusive Disease of Lower Extremities
- Show All
- Medication
- Questions & Answers
- Media Gallery
- References
