Continuous Positive Airway Pressure and Progression of Enlarged Perivascular Spaces in Adults With Obstructive Sleep Apnea.

MRI-visible brain perivascular spaces (PVSs) represent an imaging feature of cerebral small vessel disease that is associated with hypertension, diabetes, and poor sleep quality and correlated with cognitive impairment and dementia. Although research shows that sleep apnea and sleep disruption are associated with PVS volumes, few studies have investigated whether sleep apnea treatment can modify this association. We aimed to test the hypothesis that continuous positive airway pressure (CPAP) therapy can change the trajectory of PVS progression in adults with sleep apnea. In this longitudinal observational treatment study, we recruited participants from sleep clinics at the Royal Infirmary of Edinburgh and Sunnybrook Health Sciences Centre with moderate-to-severe hypoxemic sleep apnea (apnea hypopnea index ≥15 and oxygen desaturation index ≥10). Before and after a minimum 4 months of CPAP, we obtained pulse oximetry (WatchPAT) and performed brain MRI, with quantification of PVS volumes in the basal ganglia (BG) and centrum semiovale (CSO). We used linear mixed-effects models to test for associations between CPAP usage, changes in PVS volumes, and baseline sleep apnea severity. Among 64 participants (mean age 54.7 years old, 31% female) who were followed for more than a median (interquartile range) of 140 (124-163) days, there were 2 subgroups: 37 participants who used CPAP optimally (≥4 hours a night ≥70% of nights) and 27 participants who did not. Optimal CPAP usage modified the association between visit and BG PVS volumes (interaction estimate = -0.007, SE = 0.002, p = 0.007). Participants with the poor CPAP adherence experienced an increase in BG PVS (estimate = +0.005, SE = 0.001, p = 0.002). Participants with consistent CPAP adherence experienced stabilization of BG PVS volumes (estimate = -0.001, SE = 0.001, p = 0.42). This benefit was more pronounced with increased hypoxemia (mean interaction estimate = +0.004, SE = 0.001, p = 0.0009) and increased AHI (interaction estimate = -0.002, SE = 0.00009, p = 0.008). Optimal CPAP use may moderate the effects of sleep apnea on trajectories of MRI-visible PVS volumes. Although the observational nonrandomized nature of this study is a limitation, these data suggest that CPAP may be an effective means of slowing PVS dysfunction progression, a key correlate of aging and dementia, in adults with sleep apnea. NCT03410095. This study provides Class IV evidence that, in patients with moderate-to-severe sleep apnea, optimal adherence to CPAP treatment stabilizes the progression of BG PVS volume.