Peripheral arterial disease: diagnostic challenges and how photoplethysmography may help

Peripheral arterial disease (PAD) affects approximately 20% of patients aged ≥60 years.1 A GP with an average list size of 1800 patients can expect to have 50–60 patients with PAD. Ankle-brachial pressure index (ABPI), which is the ratio of the ankle to brachial systolic pressure measured by sphygmomanometer and hand-held Doppler ultrasound probe, is used to assess PAD in general practice. ABPI has been shown to have a sensitivity of 95% and specificity of 99% compared to angiographic imaging,2 however it is relatively time-consuming and requires adequately trained staff. There are limitations with ABPI in patients with diabetes, renal disease, and older people where an underestimation of disease can occur with a falsely high ratio due to the presence of incompressible calcified blood vessels.