Assessment for peripheral arterial disease

Screening for peripheral arterial disease is an essential part of high-risk foot wound assessment. To screen for peripheral arterial disease:

  • palpate pedal pulses (dorsalis pedis, posterior tibial)
  • auscultate for femoral artery bruit
  • look for signs of ischaemia (cold, pale extremities; thin hairless skin)
  • ask about symptoms of intermittent claudication (note these may be absent in patients with neuropathy)
  • check for history of cardiovascular or vascular disease.

Auscultation for femoral artery bruits can indicate significant arterial disease or occlusion. An inability to palpate pedal pulses is associated with peripheral arterial disease and the risk of amputation. However, palpable pulses alone do not reliably exclude peripheral arterial disease, so consider more advanced vascular assessment techniques.

Handheld Doppler waveform evaluation can be used to evaluate pedal pulses. The 8 MHz Doppler probe should be used when evaluating pedal waveforms. Abnormal waveforms have high accuracy for detecting peripheral arterial disease. Abnormal Doppler waveforms typically sound unclear, have low volume and only one phase. Normal waveforms are loud, clear and have two to three phases.

If peripheral arterial disease is suspected, consider pressure measurement (ie ankle brachial pressure index [ABPI], toe brachial pressure index [TBPI] or toe pressure) to assess arterial perfusion and determine if vascular referral is required. See Interpretation of lower-limb pressure measurements.

Interpret ABPI with caution in patients older than 75 years and those with kidney disease or diabetes. In such patients, ABPI can be artificially inflated by arterial calcification. An ABPI within the normal range in a patient with a strong clinical presentation for peripheral arterial disease does not exclude peripheral arterial disease. Measuring the toe pressure or TBPI is useful for patients with an ABPI greater than 1.3, or if the ABPI result does not fit within the clinical context of the patient, or for patients who do not respond to therapy as expected.

Table 1. Interpretation of lower-limb pressure measurements

ABPI

Less than 0.9: indicative of peripheral arterial disease

0.9 up to 1.3: normal

Greater than 1.3: indicative of calcification; further testing required for peripheral arterial disease

TBPI

Less than 0.7: indicative of peripheral arterial disease

Greater than or equal to 0.7: normal

Toe pressure

Less than 30 mmHg: unlikely to heal

30 to 50 mmHg: poor healing capacity

Less than 96 mmHg: indicative of peripheral arterial disease in general population

Less than 97 mmHg: indicative of peripheral arterial disease in diabetes population

Note: ABPI = ankle brachial pressure index; TBPI = toe brachial pressure index

For management of patients with peripheral arterial disease, see Interventions for wounds on a high-risk foot.