Definition
A.Lower extremity peripheral artery disease (PAD) is the obstruction of blood flow in the lower extremity arteries.
Incidence
A.The incidence of lower extremity PAD increases with age.
1.5% of adults over 50 years of age.
2.14.5% of adults over 70 years of age.
Pathogenesis
A.Lower extremity PAD is frequently caused by atheroma in the walls of the arteries.
B.PAD, coronary artery disease, and cerebral artery disease are all manifestations of atherosclerosis and commonly occur together.
Predisposing Factors
A.Age 70 years and older.
B.Age 50 to 69 years with a history of smoking or diabetes.
C.Age 40 to 49 with diabetes and at least one other risk factor for atherosclerosis.
D.Known atherosclerosis at other sites (e.g., coronary, carotid, renal artery disease).
E.Hypertension.
F.Smoking.
G.Hyperlipidemia.
H.Homocysteinemia.
I.Diabetes.
Subjective Data
A.Common complaints/symptoms.
1.The PAD Fontaine Classification score lists the common symptoms in accordance with disease progression.
B.Common/typical scenario.
1.Patient will report painful cramping during walking or exercise.
2.Elicit onset, duration, location, and intensity of pain. (Intermittent claudication pain is typically a muscle tightness in the buttock, thigh, or calf that comes on with exercise and is relieved at rest.)
3.Inquire what aggravates and relieves the pain.
a.Is the leg pain worse when legs are elevated or down?
b.Is there resting pain or nocturnal cramping? (With critical limb ischemia, resting leg pain is aggravated when the legs are elevated.)
4.Question the patient about cardiovascular-related conditions: Coronary artery disease, myocardial infarction, carotid artery disease, trans-ischemic attack, or strokes.
5.Question the patient about other medical conditions such as diabetes, chronic kidney disease, heart failure, chronic obstructive pulmonary disease, and hematology conditions.
6.Inquire about musculoskeletal conditions such as osteoarthritis and spinal degeneration.
C.Review of systems.
1.Musculoskeletal.
a.Inquire about aching, tightness, or squeezing pain in the calf, thigh, or buttocks.
b.Ask about pain before walking versus pain that starts during walking.
Physical Examination
A.Atherosclerotic disease is a diffuse process. Therefore, the examination, regardless of the complaint (intermittent claudication, angina, transient ischemic attack), should include the entire arterial system.
1.Check blood pressure in both arms, heart rate, and rhythm.
2.Inspect full length of upper and lower extremities: Dry, shiny hairless skin, muscle atrophy, color, necrotic and/or gangrenous ulcers, or evidence of distal embolization in the fingers and/or toes (blue toe syndrome).
3.Auscultate.
a.Heart to listen for arrhythmias, gallops, and murmurs.
b.Carotid, brachial, abdominal aorta, femoral, and popliteal pulses to listen for bruits.
c.Lung fields.
4.Palpate.
a.Abdomen to assess for a pulsatile mass (aortic aneurysm).
b.Leg: Femoral, popliteal, dorsalis pedis, and post tibial pulses.
c.Arm: Brachial, radial, ulnar pulses.
d.Check capillary refill, strength, and sensation of upper and lower extremities.
5.Beurger test to assess for positional rubra (with significant PAD, foot is paler with elevation and then rubrous or cyanotic in the dependent position).
6.10 g monofilament foot test to assess for peripheral neuropathy.
Diagnostic Tests
A.Ankle–brachial index has a high sensitivity and specificity for the identification of PAD. Inclusion of the toe–brachial index or continuous wave Doppler (if tissue is intact) assessment increases detection of serious PAD.
B.Radiological imaging of arterial leg circulation such as ultrasound, CT, or MRI is best reserved for vascular services as part of the treatment decision and workup.
C.Abdominal aorta screening is recommended due to the correlation between PAD and abdominal aortic aneurysm. Ultrasound is the modality of choice.
D.Hematologic evaluation: Complete blood count, fasting blood glucose, fasting lipids, serum creatinine, urinalysis.
Differential Diagnosis
A.Arterial aneurysm.
B.Arterial dissection.
C.Embolism.
D.Popliteal entrapment syndrome.
E.Adventitial cystic disease.
F.Thromboangitis obliterans (Buerger’s disease).
G.Limb trauma.
H.Nonarterial etiologies for limb pain: Neurogenic, musculoskeletal causes, pathologic.
Evaluation and Management Plan
A.General plan.
1.Peripheral arterial disease management is dependent on symptom severity, comordid condition, and whether or not a patient will experience a meaningful benefit from a technically successful procedure.
2.Patients with PAD should have a cardiovascular risk reduction plan.
a.Smoking cessation is critical.
b.Treatment of diabetes if applicable to achieve an HbA1c less than 5.5 mmol/L.
c.Healthy diet and exercise.
d.Hematologic evaluation (see section “Diagnostics Tests“). Results will guide further therapy.
e.Additional management plan for patients with intermittent claudication (Fontaine IIa and IIb) includes:
i.Structured exercise program.
ii.Referral to vascular service if intermittent claudication is lifestyle limiting and patient may benefit from revascularization treatment.
3.Critical limb ischemia (Fontaine III) and necrosis and gangrene (Fontaine IV) management plan will depend on progression of limb symptoms, comorbid conditions, and conduit availability.
a.Supportive measures may include:
i.Wound management.
ii.Antibiotic therapy if underlying cellulitis or wound infection (consider Flucloxacillin).
iii.Pain management.
b.Vascular treatment may include:
i.Endovascular revascularization.
ii.Bypass surgery.
iii.Digit or limb amputation.
B.Patient/family teaching points.
1.Patients should seek out a provider if they experience pain, numbness, tingling, weakness, or significant temperature change in their extremities.
2.Patients should also report open sores that do not heal.
C.Pharmacotherapy.
1.Antiplatelet therapy with long-term low-dose aspirin.
2.Treatment of hyperlipidemia with a statin to achieve a low-density lipoprotein level less than 100 mg/dL (<70 mg/dL if PAD and a history of coronary or cerebral artery disease).
3.Treatment of hypertension to achieve a blood pressure less than 140/90 mmHg (<130/80 mmHg for patients with diabetes or renal failure).
4.Consider pharmacology therapy. In the United States only pentoxifylline and cilostazol have achieved Food and Drug Administration (FDA) approval for the treatment of intermittent claudication.
D.Discharge.
1.Patients need to be taught to make healthy dietary changes, keep cholesterol levels down, maintain a healthy weight, and stop smoking.
Follow-Up
A.Three-month primary care review of cardiovascular risk management.
B.If treated percutaneously or surgically, outpatient vascular review after 4 to 6 weeks.
Consultation/Referral
A.Consultation and referral are dependent on symptom status. Patients with lower extremity PAD have a wide spectrum of symptoms.
1.Fontaine Classification I: Asymptomatic. Conservative management.
2.Fontaine Classification IIa: Intermittent claudication greater than 200 m (and nonlifestyle limiting). Conservative management.
3.Fontaine Classification IIb: Intermittent claudication less than 200 m (or lifestyle limiting). Refer to vascular service.
4.Fontaine Classification III: Nocturnal or resting pain. Referral to vascular service.
5.Fontaine Classification IV: Necrosis and gangrene. For hospital admission, vascular consult.
Special/Geriatric Considerations
A.Patients with PAD are usually elderly.
B.Younger patients are usually diabetic.
Bibliography
Cronenwett, J. L., & Johnston, K. W. (2014). Rutherford’s vascular surgery (8th ed.). Philadelphia, PA: Elsevier Saunders.
Mitchell, M. E., & Carpenter, J. P. (2017). Overview of acute arterial occlusion of the extremities (acute limb ischaemia). Retrieved from www.uptodate.com
Neschis, D. G., & Golden, M. A. (2018, June 11). Clinical features and diagnosis of lower extremity peripheral artery disease. In K. A. Collins (Ed.), UpToDate. Retrieved from https://www.uptodate.com/contents/clinical-features-and-diagnosis-of-lower-extremity-peripheral-artery-disease
Rasmussen, T. E., Clouse, W. D., & Tonnessen, B. H. (2011). Handbook of patient care in vascular diseases (5th ed.). Philadelphia, PA: Wolters Kluwer Health.
Tehan, P. E., Bray, A., & Chuter, V. H. (2016). Non-invasive vascular assessment in the foot with diabetes: Sensitivity and specificity of the ankle brachial index, toe brachial index and continuous wave Doppler for detecting peripheral arterial disease. Journal of Diabetes and Its Complications, 30(1), 155–160. doi:10.1016/j.jdiacomp.2015.07.019