Ankle-brachial pressure index

Ankle-brachial pressure index (ABPI) or Ankle-brachial index (ABI) is a non-invasive diagnostic procedure used to assess the peripheral arterial disease (PAD). It is a simple, reliable means for diagnosing PAD. The ABPI is the ratio of the blood pressure at the ankle to the blood pressure in the upper arm (brachium).

Procedure

The ABPI is calculated by dividing the systolic blood pressure at the ankle by the systolic blood pressure in the arm. The blood pressure measurements are usually taken using a Doppler ultrasound device. The highest pressure recorded is used to calculate the ABPI.

Interpretation

An ABPI of 1.0 to 1.4 is considered normal. An ABPI less than 1.0 indicates that there may be significant peripheral arterial disease. An ABPI of less than 0.5 indicates severe peripheral arterial disease. An ABPI greater than 1.4 may suggest non-compressible arteries, which can occur in patients with long-standing diabetes or renal disease.

Clinical significance

The ABPI is used to assess the severity of peripheral arterial disease and the risk of future cardiovascular events. It can also be used to monitor the response to treatment in patients with peripheral arterial disease.

Limitations

The ABPI has some limitations. It may not be accurate in patients with non-compressible arteries. It may also be less accurate in patients with severe leg edema or in patients who have recently exercised.

See also

• Peripheral artery disease
• Doppler ultrasound
• Blood pressure