Diagnostics

• Acutely cold, painful limb: Suspect ALI, consult vascular surgery immediately for urgent revascularization. [7][9]

• Claudication, rest pain, or CLI

  • Perform a comprehensive history and physical examination.

  • Measure ABI.

• PAD confirmed (based on clinical features and ABI) [7][9]

  • Obtain imaging if revascularization is planned or if the diagnosis remains uncertain.

ABI is the ratio of systolic ankle blood pressure to systolic brachial blood pressure.

Resting ABI

• Indications

  • First-line diagnostic test for nonacute PAD (i.e., intermittent claudication, rest pain, or CLI) [11]

• Technique

  • Ask the patient to rest in the supine position for approx. 10 minutes.

  • Place the blood pressure cuffs on the ankles and the arms.

  • Locate the pulse using the Doppler.

  • Inflate the cuff until the pulse is no longer audible on the Doppler device, and then inflate the cuff by a further 20 mm Hg.

  • Deflate the cuff slowly, and note the pressure at which the pulse is audible again.

    • Ankle pressure

      • Measure systolic pressure of bilateral dorsalis pedis and posterior tibialis arteries.

      • Note the higher systolic pressure of either the dorsalis pedis or the posterior tibial artery of each leg.

    • Brachial pressure

      • Measure systolic pressure of bilateral brachial arteries.

      • Note the higher brachial blood pressure of either arm.

  • Calculate the ABI for each leg: Divide the highest ankle pressure by the highest brachial pressure.

• Description: ABI testing following extended exercise of the lower extremity

• Indication: suspicion of PAD in a patient with a normal or borderline ABI

• Angiography: preferred modality for assessment for revascularization

  • Modalities [18]

    • First-line: MR angiography (MRA) without and with IV contrast

    • Contraindications for MRI (e.g., prior stent placement): CT angiography with IV contrast (CTA)

    • Digital subtraction angiography: considered the gold standard for PAD; uncommonly used [19]

  • Findings: demonstration of site(s) and extent of arterial occlusion or stenosis and collateral blood flow

• Duplex ultrasound [19]

  • Indications [18]

    • Patients with contraindications for angiography (e.g., contrast allergy)

  • Findings: Elevated peak systolic velocity (PSV) and PSV ratio suggest PAD.