Toe blood pressure. A valuable adjunct to ankle pressure measurement for assessing peripheral arterial disease

Ankle pressure measurements fail to reflect the severity of peripheral ischemia when the underlying vessels are calcified or when there is extensive pedal or digital arterial disease. These problems may be obviated by measuring pressures at toe level. In this study, toe pressures were correlated with ankle pressures, clinical symptoms, and the presence or absence of diabetes in 294 limbs. The relationship of toe pressures to healing of ulcers or amputations of the foot was investigated in 58 limbs. Measurements were made with a digital pneumatic cuff and a photoplethysmograph. The ability of absolute toe pressure, ankle/brachial index, toe/brachial index, toe/ankle index, and the brachial pressure minus the toe pressure to differentiate between asymptomatic, claudicating, and ischemic limbs was determined. The toe/brachial index, arm minus toe pressure, and the absolute toe pressure had an average sensitivity and specificity of 85% and 88% for asymptomatic limbs and 89% and 86% for ischemic limbs. A toe pressure greater than 30 mmHg was indicative of a good healing potential, and ankle pressure less than 80 mmHg was associated with poor healing. The correlation between ankle and toe pressures was essentially the same in both diabetic (r = 0.60) and non-diabetic limbs (r = 0.62).