Photoplethysmography, an Easy and Accurate Method for Measuring Ankle Brachial Pressure Index: Can Photoplethysmography Replace Doppler?

Objective: To assess the accuracy of ankle brachial pressure index (ABPI) assessed by photoplethysmography (PPG) compared with continuous wave Doppler (CW-Doppler). Methods: Ankle brachial pressure index was measured in a standard manner using both PPG and Doppler probes. For PPG-ABPI, a PPG probe was placed on the index finger and great toe, and a microcomputer determined the ABPI. These values were compared with the ABPI measured manually using an 8-MHz Doppler probe. Correlation and agreement between PPG and Doppler ABPI were assessed by Lin’s correlation coefficient and Bland—Altman plots. Results: In all, 133 claudicants were assessed. There was a strong correlation between the 2 ABPI methods (β = .79 and 95% limits of agreement of —0.23 to 0.24). Conclusion: Measuring ABPI automatically using the PPG technique is an effective alternative for Doppler ABPI. PPG-ABPI is completely objective, fast, and accurate.