O053 Relationship between cardiovascular risk and pulse wave amplitude characteristics in a sleep clinic cohort

Abstract Introduction Novel pulse oximetry-derived measures of autonomic vasoreactivity have recently been developed as a biomarker of cardiovascular outcomes in patients with obstructive sleep apnoea (OSA). It is currently unclear if these measures relate to general cardiovascular risk in an unselected population undergoing polysomnography. Methods This study examined pulse wave amplitude characteristics (from photoplethysmography) in 547 individuals who underwent a diagnostic in-laboratory polysomnogram and had sufficient clinical data to calculate a modified Framingham cardiovascular risk score. Individuals were categorised as either having an established cardiovascular disease (CVDest, n=47) or a calculated Framingham 10-year CVD risk score that was low (CVDlow-risk, n=177) or intermediate-to-high (CVDelevated-risk, n=323). Standard polysomnography variables and the pulse-wave amplitude drops index (defined by the number of drops in pulse wave amplitude of >30% per hour of sleep, PWADIn) were derived and compared between the 3 groups. Results The PWADIn was significantly different between each of the CVD risk groups (CVDest: 37.8±19.1; CVDelevated-risk: 42.2±22.3; CVDlow-risk: 50.6±19.3, p<0.01). Similar findings were observed for PWADIn during REM and non-REM sleep, and group differences in PWADIn remained significant (p<0.01) after adjusting for apnoea-hypopnea index, age, sex, and body mass index. Conclusions These data indicate that pulse oximetry-derived measures of autonomic vasoreactivity may provide a marker of cardiovascular disease risk in a general sleep clinic population undergoing polysomnography. The mechanistic link between recurrent nocturnal pulse wave amplitude drops and cardiovascular disease risk requires further study.