Pulse wave amplitude drops (PWAD) index: a biomarker of cardiovascular risk in patients with obstructive sleep apnea in three cohorts.

Abstract

<b>Introduction :</b> This study aimed to investigate the value of pulse wave amplitude drops (PWAD) index during sleep as a biomarker of cardiovascular risk in patients with obstructive sleep apnea (OSA). <b>Materials and Methods :</b> This is a prospective analysis of three cohorts: 1) the HypnoLaus population-based cohort (N=1941), 2) ISAACC randomised controlled trial in patients with acute coronary syndrome (N=692); 3) the Pays de la Loire Sleep Cohort (PLSC), a prospective clinical cohort (N= 6367). PWADs were derived from pulsoximetry signal. The total number of PWAD (&gt;30%) per hour during sleep was averaged (PWAD index). Participants were divided into subgroups according to the presence of OSA (apnea/hypopnea +/−15/h) and the median PWAD index (high/low) in each cohort. Primary endpoint was the incidence of a composite of cardiovascular events. <b>Results :</b> After 49.2±12.1 months, 24.3±5.8 months, 72.4±35.4 months of follow up, 3.9%, 16.9%, 10.5% developed a CV event in the HypnoLaus, ISAACC, PLSC cohorts respectively. Using Cox models controlling for CV risk factors, OSA+/Low PWAD group had a higher incidence of CV events compared to OSA+/high PWAD group in HypnoLaus (p=0.031) and in PLSC (p&lt;0.005) and also compared to OSA- group in HypnoLaus (p=0.022) and in PLSC (p&lt;0.005). In ISAACC, OSA+/low PWAD untreated group had higher recurrent of CV events rate compared to OSA- group (p=0.028). This difference disappeared when this group was treated with CPAP. <b>Conclusions :</b> In OSA+ patients, low PWAD-index was independently associated with a higher incidence of CV events in the three different cohorts and could represent an interesting biomarker of CV risk in OSA.