Screening Peripheral Artery Disease Using the Systolic Rise Time Measured with Photoplethysmography
Author(s):
Samantha Amrani1, Anissa Benbia1, Kornelia Eveilleau3, Hasan Obeid2, Imad Abi-Nasr2, Majid Tayyarah4, Magid Hallab2
and Georges
Leftheriotis1*
Screening for Peripheral Artery Occlusive Disease (PAOD) remains a challenge in the prevention and care of patients with arteriosclerosis. The Ankle Brachial Index (ABI) is currently the gold standard. However, ABI is time consuming and requires some expertise to perform which is a limiting factor for global screening. The measurement of the Systolic Rise Time (SRT) of the pulse wave of the lower limb may provide an easier alternative to detect PAOD. In a retrospective pilot study, we analyzed the possibility of detecting PAOD using the SRT of the toe waveform using the Photo-PlethysmoGraphic signal (PPG).Methods: We measured 79 subjects (41 patients diagnosed with different stages of PAOD and 38 healthy volunteers without known PAOD). In each subject, at least one lower limb was assessed with classical ABI (minimum of 2 tibial arteries using a Doppler probe). All subjects underwent a PPG assessment on the finger and the toe simultaneously using pOpmètre® (Axelife – France). In-house software (JAVA) was used to calculate the SRT of all recorded signals.Results: from the 154 lower limbs recorded, 8 were excluded for technical reasons: problematic cuff measurement of the ABI (in very severe PAOD, medial calcification & amputation) or bad quality of the PPG signal with very low amplitude. Finally, 146 lower limbs were analyzed including 72 healthy and 74 subjects with PAOD. The mean age of the population was 69±12 years with 75% men, 6% diabetics, 47% hypertensive, 49% without clinical PAOD defined as stage 0 in this study; 16% in stage 1; 32% in stage 2; 2% in stage 3 and 1% in stage 4 according to the Leriche classification. The SRT cut-off value of 160 ms identifies PAOD with a sensitivity of 78% vs 73% for ABI < 0.9 and a specificity of 86% vs 87%; a positive predictive value (PPV) of 85% vs 86% and a negative predictive value (NPV) of 79% vs 75%. In addition, the ratio between toe-SRT and finger-SRT cut-off value of 1 identifies PAOD with a sensitivity of 76% and a specificity of 74%.Conclusion: SRT measured using a PPG pulse signal of the toe is promising as a simple non-invasive method to diagnose PAOD (duration <14 seconds) and determine if is there any PAOD with similar specificity and sensitivity to the reference method. These results need to be confirmed through a prospective study.
