Segmental limb pressure testing

Segmental limb pressures are measured by combining Doppler ultrasound with blood pressure measurements at various locations in the arms and legs. The test can be done with either 3 or 4 cuff technique. By detecting differences in blood pressure at specific locations in different limbs, this test helps to diagnose peripheral arterial disease.

As blood flows from proximal to distal, intra-arterial pressures will increase moving in the same proximal to distal distribution.  In normal healthy individual the thigh pressures should typically exceed ankle pressures.  Thigh/brachial index of 1.1 or greater is considered normal and index of less than 0.9 indicates peripheral arterial disease.  If the thigh/brachial indexes are abnormal bilaterally the site of obstruction is assumed to be in the aortoiliac region.  If unilaterally abnormal iliac or common femoral stenosis is usually suspected.  Below the thigh segmental limb pressures are compared to the adjacent segments and a reduction between 20-30 mmHg is considered borderline, with a reduction greater than 30 mmHg is considered abnormal.

In the next post we will discuss pulse volume phythysmography and it’s interpretation.