Diagnostic Potential of Combined Photoplethysmography and Ankle‐Brachial Index in Peripheral Arterial Disease: A Duplex Ultrasonography‐Based Comparative Study

Background Although ankle‐brachial index (ABI) and photoplethysmography (PPG) have also shown adequate sensitivity in detecting peripheral arterial disease, their diagnostic performance is less reliable in asymptomatic cases or those with high atherosclerotic cardiovascular risks. Methods and Results We evaluated 130 participants using ABI, PPG, and duplex ultrasonography, diagnosing 65 with peripheral arterial disease. From the PPG, we derived 2 parameters: PPG amplitude ratio of the lower‐to‐upper extremities (PPGratio) and the PPG amplitude of the lower extremity (PPGamp). Sensitivity, specificity, accuracy, and the area under receiver operating characteristic (ROC) curve were calculated for PPG parameters and ABI, and their combination of both methods. Univariate and multivariate logistic regression assessed the prognostic potential of these parameters. ROC analysis revealed optimal cutoff values in diagnosing peripheral arterial disease were 0.417 for PPGratio and “58” for PPGamp. Both PPGratio and PPGamp demonstrated significantly higher sensitivities, 78.4% and 75.7%, respectively, compared with 55.9% for ABI