Photoplethysmography and continuous-wave Doppler ultrasound as a complementary test to ankle-brachial index in detection of stenotic peripheral arterial disease.

PURPOSE: We evaluated the sensitivity and specificity of ankle-brachial index (ABI), photoplethysmography (PPG), and continuous-wave Doppler ultrasound (CWD) in the detection of anatomically stenotic peripheral arterial disease (PAD).
METHODS: Ninety-seven patients (194 legs) patients who had coincidentally undergone computed tomography angiography (CTA), ABI, PPG, and CWD for the evaluation of PAD were retrospectively reviewed. Sensitivity and specificity were measured.
RESULTS: Among 194 legs, 163 (84%) legs had stenotic PAD on CTA. Overall sensitivity of ABI, PPG, and CWD was 69.3%, 81.6%, and 90.8% and specificity was 96.8%, 77.4%, and 64.5%, respectively. Ankle-brachial index showed a statistically significantly decreased sensitivity (14.8%) for below trifurcation level stenosis compared with CWD (92%) and PPG (67%). The sensitivity of ABI was also significantly decreased in single level and moderate stenosis (45.1% and 42.1%, respectively). In contrast, the sensitivity of CWD and PPG was not significantly decreased.
CONCLUSION: The ABI showed significantly decreased sensitivity especially in stenosis below the trifurcation level. Both PPG and CWD were complementary to ABI in these groups of patients.