The Impact of Coronary Artery Disease on Brain Vascular and Metabolic Health: Links to Cognitive Function
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Background
Coronary artery disease (CAD) is the leading cause of mortality worldwide and is associated with an increased incidence of cognitive decline, however the pathological mechanisms linking CAD to brain and cognitive health remain unclear. Prior research has identified regional deficits in cerebral blood flow (CBF) and cerebrovascular reactivity (CVR), a measure of vascular reserve, in patients with CAD. However, the impact of these cerebrovascular deficits on cognition has not been explored, nor has the effect of CAD on cerebral metabolic health. This study aims to fill these gaps by investigating how CAD influences cerebral vascular and metabolic health, and how these alterations relate to cognitive function across multiple domains.
Methods
Quantitative magnetic resonance imaging (MRI) was employed to measure a comprehensive profile of cerebral vascular and metabolic health, including CBF, CVR, cerebral metabolic rate of oxygen (CMRO₂), and oxygen extraction fraction (OEF). Cognition was assessed using a validated neuropsychological battery from which composite scores were extracted, reflecting executive functions, working memory, processing speed, and verbal episodic memory.
Results
A total of 35 patients with CAD and 37 healthy controls were included in the final analysis. Patients with CAD demonstrated widespread impairments in both cerebral vascular and metabolic health, characterized by lower CBF, CVR, and CMRO₂, and increased OEF, indicative of insufficient oxygen delivery. Notably, lower CVR was associated with poorer executive function, suggesting a specific role of vascular reserve for preserving executive functions. Furthermore, higher OEF was associated with poorer working memory, showing the importance of preserved oxygen consumption for maintaining cognitive function.
Conclusion
This study reveals that CAD is associated with impaired cerebral vascular and metabolic health, providing a pathological basis for cognitive decline. Specifically, reduced CVR and elevated OEF emerged as sensitive biomarkers linking impaired brain health and cognition. These markers hold promise for guiding future interventions aimed at preserving cognitive health in patients with CAD.
Clinical Perspective
What Is New?
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Coronary artery disease is associated with an increased incidence of cognitive decline but the biological mechanisms underlying these changes in cognition are unclear.
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This is the first study to comprehensively demonstrate profound and widespread deficits in both cerebral vascular and oxidative metabolic health in patients with coronary artery disease.
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Cerebrovascular reactivity and oxygen extraction fraction may be sensitive biomarkers of early cognitive decline in coronary artery disease.
What Are the Clinical Implications?
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The widespread impairments in cerebral vascular and metabolic health suggest that coronary artery disease has profound consequences on the brain.
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Poor vascular reserve and an imbalance between oxygen delivery and usage may be crucial determinants of cognitive health. These results highlight the limitations of traditional biomarkers in understanding the brain’s vulnerability and the need for these novel and quantitative biomarkers of cerebral physiological health.
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These findings suggest that cerebral vascular and metabolic deficits exist even in the absence of overt cognitive decline in coronary artery disease, emphasizing the need for early detection and preventative strategies.
