Peripheral Arterial Disease Diagnosis and Management

Initial Assessment

A comprehensive vascular assessment, including ankle-brachial index (ABI) measurement, segmental pressures with pulse volume recordings, and duplex ultrasound of the lower extremity arterial system, is recommended to determine the extent and severity of peripheral arterial disease in patients, as suggested by the American College of Radiology and the American College of Cardiology 1, 2, 3
Segmental pressures with pulse volume recordings (PVR) help localize the level of arterial obstruction and provide a functional assessment of arterial flow, particularly when ABI is unreliable due to calcified vessels, according to the American College of Cardiology 2, 3
Duplex ultrasound of lower extremity arteries evaluates anatomic location and degree of stenosis, assesses flow characteristics throughout the arterial tree, and helps determine if there is collateral flow, as recommended by the American College of Radiology and the American College of Cardiology 1, 2

For patients with mild-to-moderate disease (ABI 0.41-0.90), the American College of Radiology and the American College of Cardiology recommend considering CT angiography (CTA) with runoff to assess the entire arterial tree from abdomen to foot 1, 2
For patients with severe disease (ABI ≤0.40) or critical limb ischemia, urgent vascular imaging with CTA or MRA is indicated, and consideration of direct referral to vascular surgery is recommended by the American College of Cardiology and Anaesthesia 2, 3, 4
If non-compressible vessels are suspected (ABI >1.40), the American College of Cardiology suggests performing toe-brachial index (TBI) measurement (normal >0.70) and considering alternative tests like transcutaneous oxygen pressure measurement 3
The following ABI ranges are associated with different levels of PAD:
ABI Range PAD Level
1.00-1.40 Normal
0.91-0.99 Borderline
0.71-0.90 Mild-to-moderate PAD
0.41-0.70 Moderate-to-severe PAD
≤0.40 Severe PAD/Critical limb ischemia

ABI Range	PAD Level
1.00-1.40	Normal
0.91-0.99	Borderline
0.71-0.90	Mild-to-moderate PAD
0.41-0.70	Moderate-to-severe PAD
≤0.40	Severe PAD/Critical limb ischemia

The American College of Cardiology recommends risk factor modification, antiplatelet therapy, statin therapy, and supervised exercise program for asymptomatic or mildly symptomatic disease 2
For moderate-to-severe symptomatic disease, the American College of Cardiology suggests all of the above plus consideration of revascularization and referral to vascular specialist for intervention planning 2, 3
For critical limb ischemia, urgent revascularization assessment and wound care if tissue loss is present are recommended by the American College of Cardiology and Anaesthesia 2, 4
Antiplatelet therapy with aspirin (75-325 mg/day) or clopidogrel (75 mg/day), and statins with an LDL-C goal of <1.4 mmol/L (<55 mg/dL) or a ≥50% reduction are recommended by the American College of Cardiology 7, 8
Cilostazol 100 mg twice daily is recommended for patients with limiting claudication (contraindicated in heart failure) 7
Supervised exercise (30-45 minutes, at least 3 times a week for 12+ weeks), smoking cessation, and control of risk factors (hypertension, diabetes, dyslipidemia) are also recommended 7
Anticoagulation is not recommended for reducing cardiovascular events in PAD 7, 8

ABI measurement should be performed with the patient in a supine position with 5-10 minutes of rest, in a constant ambient temperature, as recommended by the American Heart Association 5, 6
The recommended sequence for measuring ABI is: first arm, first posterior tibial artery, first dorsal foot artery, second posterior tibial artery, second dorsal foot artery, and second arm 5, 6
For ABI calculation, the higher of the two ankle pressures (posterior tibial or dorsalis pedis) is typically used as the numerator, and the higher of the two brachial systolic pressures is used as the denominator 5, 6
The toe-brachial index (TBI) (normal >0.70) can be used as an alternative diagnostic test 6, 5
Other alternative tests include Doppler waveform analysis, pulse volume recording, and imaging studies (duplex ultrasonography, angiography) 8

Regular follow-up of ABI is recommended to monitor disease progression and response to treatment 6
Functional assessment, including objective tests of functional performance, and quality of life evaluation using questionnaires should also be considered 6
A low ABI of 0.5 indicates significantly increased cardiovascular risk, with a 4.2-fold higher risk of cardiovascular mortality in men, and patients with low ABI may benefit from aggressive management of cardiovascular risk factors, antiplatelet therapy, statin treatment, and supervised exercise therapy 5