<p>The ankle brachial pressure index (ABPI) was originally described by Nauman in 1930; but it was Winsor who was first to use the test on patients with peripheral arterial disease (PAD), circa 1950. It was another 20 years, however, before Yao noticed that the reduction in ABPI was linked with the severity of peripheral arterial disease (Caruana et al, 2005; Khan et al, 2008; Aboyans et al, 2012).</p>