Abstract 14917: The Influence of Coronary Artery Disease on Cerebrovascular Reactivity and Cognitive Function

Introduction: Patients with coronary artery disease (CAD) are at increased risk of cognitive decline. A proposed mechanism is cerebral hypoperfusion related to vascular dysfunction and impaired cerebral blood flow regulation Hypothesis: Patients with CAD will have lower cerebrovascular function than age- and sex-matched controls, assessed as reactivity to a vasodilatory carbon dioxide (CO 2 ) stimulus. Methods: Adults 40-70years old with CAD were recruited on enrollment to a cardiac rehabilitation program following a cardiac event or hospitalization. Age and sex-matched adults without known disease or cardiovascular risk factors were recruited as healthy controls. Cognitive function was assessed by the Fluid Composite of the NIH Cognition Toolbox. Following a familiarization visit, participants underwent a stepped CO 2 protocol (room air, 2% CO 2 , 4% CO 2 , 6% CO 2 ) while continuously measuring middle cerebral artery velocity (MCAv) using transcranial doppler ultrasound, mean arterial pressure (MAP), ventilation (VE), and end-tidal CO 2 . Cerebrovascular conductance (CVCi) was calculated as MCAv/MAP. Cerebrovascular reactivity was calculated as the linear regression slope of CVCi against the change in end-tidal CO 2 . The reactivity of MAP and VE (or chemosensitivity) were also calculated. Results: 19 patients with CAD and 10 healthy controls were recruited ( Table 1 ). Compared with controls, patients with CAD had a 2-fold lower cerebrovascular reactivity (p=0.003), higher MAP reactivity (p<0.05), and a trend towards higher chemosensitivity (p<0.1) ( Table 2 ). There were no group differences in resting CVCi or cognition ( Table 2 ). After adjustment for age and sex, lower cerebrovascular reactivity was associated with lower peak oxygen uptake, diabetes, and smoking history ( Table 3 ). Conclusions: Compared with healthy controls, we report that patients with CAD have significantly lower cerebrovascular function, with no differences in cognitive function.