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References: See page 112.
Vascular and Orthopedic
Surgery
Peripheral Arterial Occlusive
Disease
Peripheral arterial occlusive disease affects about 18
percent of persons over 70 years of age. The disease
presents with intermittent claudication with pain in the
calf, thigh or buttock, which is elicited by exertion and
relieved with a few minutes of rest. In most cases, the
underlying etiology is atherosclerotic disease of the
arteries.
I. Pathophysiology
A. The incidence of claudication rises sharply between
ages 50 and 75 years, particularly in persons with
coronary artery disease. This condition affects at
least 10% of persons over 70 years of age and 2%
of those 37-69 years of age.
B. Risk factors. Cigarette smoking is the most
important risk factor for PAOD. Seventy to 90% of
patients with arterial insufficiency are smokers.
Other risk factors include hyperlipidemia, diabetes
mellitus, and hypertension.
C. After five years, 4% of patients with claudication
lose a limb and 16% have worsening claudication
or limb-threatening ischemia. The five-year
mortality rate for patients with claudication is 29%;
60% of deaths result from coronary artery disease,
15% from cerebrovascular disease, and the
remainder result from nonatherosclerotic causes.
II. Clinical evaluation of claudication
A. Claudication
1. The key clinical features of claudication are
reproducibility of muscular pain in the thigh or
calf after a given level of activity and cessation of
pain after a period of rest.
2. Patients should be asked about the intensity of
claudication, its location, and the distance they
have to walk before it begins. The degree of
functional impairment should be assessed.
3. Aortoiliac disease is manifest by discomfort in
the buttock and/or thigh and may result in
impotence and reduced femoral pulses.
Leriche's syndrome occurs when impotence is
associated with bilateral hip or thigh
claudication.
4. Iliofemoral occlusive disease is characterized
by thigh and calf claudication. Pulses are
diminished from the groin to the foot.
5. Femoropopliteal disease usually causes calf
pain. Patients have normal groin pulses but
diminished pulses distally.
6. Tibial vessel occlusive disease may lead to
foot claudication, rest pain, non-healing wounds,
and gangrene.
7. Rest pain consists of severe pain in the distal
portion of foot due to ischemic neuritis. The pain
is deep and unremitting, and it is exacerbated by
elevation of the foot and is relieved by dangling
the foot over the side of the bed.
III. Physical examination
A. Evaluation of the peripheral pulses should
include the femoral, popliteal, posterior tibial, and
dorsalis pedis arteries. Pallor on elevation of the
extremity and rubor when the limb is dependent is
common.
B. Other signs of chronic arterial insufficiency include
brittle nails, scaling skin, hair loss on the foot and
lower leg, cold feet, cyanosis, and muscle atrophy.
The feet should be inspected for skin breakdown or
ulceration.
C. Bruits may be auscultated distal to the arterial
obstruction. Abdominal examination for a pulsatile
mass should be performed because of the
association between abdominal aortic aneurysm
and peripheral arterial disease.
D. Ankle-brachial index is an effective screening tool.
The ankle-brachial index is calculated by dividing
the ankle pressure by the brachial systolic
pressure.
1. The normal ABI is above 1.0, since the pressure
is higher in the ankle than in the arm.
2. An ABI below 0.9 has a 95 percent sensitivity for
detecting angiogram-positive peripheral vascular
disease.
3. An ABI of 0.40 to 0.90 suggests a degree of
arterial obstruction often associated with
claudication.
4. An ABI below 0.4 represents advanced ischemia
5. In patients with an abnormal ankle-brachial
index, testing with segmental arterial pressures
and a pulse volume recording before and after
exercising to the point of absolute claudication
are indicated.
Ankle-Brachial Index Interpretation
Normal >1
Abnormal
Intermittent 0.4-0.9
claudication
Severe less than 0.4
disease/ischemia
E. Segmental arterial pressures. The proximal lower
extremity pressures should be equal to or greater
than the upper extremity pressures, and the drop in
Doppler pressure between segments no greater
than 20 mm Hg. These studies help predict the
location and severity of the disease.
F. Arteriography or magnetic resonance
angiography is required to delineate the extent of
the disease when intervention is anticipated.
IV. Management
A. Risk factor modification
1. The goals of risk factor modification in patients
with PAOD are the same as those in patients
with coronary artery disease. Hypertension
should be controlled. Beta-blockers do not
usually worsen claudication.
2. Lipid abnormalities must be treated. The
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