Pulse Wave Amplitude Drops Index: A Biomarker of Cardiovascular Risk in Obstructive Sleep Apnea

It is currently unclear which patients with obstructive sleep apnea (OSA) are at increased cardiovascular risk. To investigate the value of pulse wave amplitude drops (PWADs), reflecting sympathetic activations and vasoreactivity, as a biomarker of cardiovascular risk in OSA. PWADs were derived from pulse oximetry-based photoplethysmography signals in three prospective cohorts: HypnoLaus ( = 1,941), the Pays-de-la-Loire Sleep Cohort (PLSC; = 6,367), and "Impact of Sleep Apnea syndrome in the evolution of Acute Coronary syndrome. Effect of intervention with CPAP" (ISAACC) ( = 692). The PWAD index was the number of PWADs (>30%) per hour during sleep. All participants were divided into subgroups according to the presence or absence of OSA (defined as ⩾15 or more events per hour or