We conducted a review and analysis of the literature surrounding the relationship between OSA and stroke. By assessing studies that used transcranial doppler ultrasonography (TCD) to assess cerebral vasoreactivity and vascular compliance.  Parameters in these studies included the breath-holding index (BHI), the visual evoked flow velocity response (VEFVR), and the middle cerebral artery pulsatility and resistance indices. Risk stratification tools such as STOP-BANG and polysomnographic metrics (AHI, RDI, ODI) were evaluated in relation to these cerebrovascular markers.

Across multiple studies, a higher risk or severity of OSA was significantly associated with impaired cerebral vasoreactivity and reduced vascular compliance. This was most notable in the anterior circulation. BHI values <0.69 and VEFVR ≤14% were common among patients at moderate to high risk for OSA. Additionally, repeated episodes of overnight oxygen desaturation correlated with markers of cerebral small-vessel disease. This includes increased white matter hyperintensities and reduced vessel compliance.