images

Ankle-Brachial Index (ABI)

The Ankle-Brachial Index (ABI) test is a simple, non-invasive diagnostic tool used to evaluate blood flow in the lower extremities. It measures and compares the blood pressure at the ankle with the blood pressure in the arm.

Purpose of the ABI test: 

  • Diagnose Peripherial Arterial Disease (PAD) in individuals with symptoms like leg pain, cramping, or non-healing wounds. 
  • Assess the severity of PAD
  • Monitor disease progression or the effectiveness of treatment for PAD.
  • Evaluate the risk of cardiovascular disease or stroke.

Indications for the Test:

  • Symptoms of PAD, such as leg pain during walking, cramping or non-healing ulcers.
  • Risk factors for PAD, such as smoking, diabetes, high cholesterol and hypertension.
  • Family history of cardiovascular disease.

Procedure: 

    The patient lies flat on an examination table while blood pressure cuffs are placed on both arms and ankles. A handheld Doppler device is then used to detect blood flow and measure the systolic blood pressure at the brachial artery in the arms and at the arteries in the ankles. This helps assess the blood flow to the lower extremities. The Ankle-Brachial Index (ABI) is then calculated by dividing the blood pressure in the ankle by the pressure in the arm. This ratio provides valuable information about the circulation in the legs and can help detect peripheral artery disease (PAD), where narrowed or blocked arteries reduce blood flow to the limbs.

Results: 

    An abnormal ABI result of 0.90 or lower indicates the presence of peripheral artery disease (PAD), with the severity ranging from mild to severe depending on the degree of narrowing or blockage in the arteries. This reduced blood flow can lead to symptoms such as leg pain, cramping, or ulcers, and may require treatment to manage the condition and reduce the risk of complications. On the other hand, an ABI value greater than 1.4 suggests stiff arteries, which could be a sign of calcification, often associated with conditions like diabetes or aging. This finding typically warrants further evaluation to assess the underlying causes and determine appropriate management.