Grant: CIHR Fellowship

Complications of the heart at or shortly after birth are collectively classified as congenital heart disease (CHD) and affect about 1/100 live births. Despite advances in medicine, complications resulting from CHD arise as these individuals age. These patients experience an increased risk of early-onset dementia compared to the general population. Of note, this increased risk is greater in males than females with CHD. To examine this issue, we will measure brain blood flow in male and female young adults with CHD and compare them to age- and sex-matched healthy individuals. We will also examine how well they maintain brain blood flow when they go from sitting to standing. This is a clinical test to assess blood flow control, where people with poor control often experience light-headedness or fainting (referred to as orthostatic hypotension). We will also have participants complete assessments that test cognitive function, including attention, working memory, conceptual thinking, language and orientation, to see if blood flow to the brain is related to cognitive performance. We anticipate patients with CHD will have lower brain blood flow than healthy control participants, and these deficits will be largest in males, followed by female CHD patients during low estrogen levels then high estrogen levels. Likewise, male CHD patients will have the lowest capacity to maintain blood flow to the brain when they stand up and are the most likely to feel lightheaded, followed by female CHD patients with low estrogen levels. We further anticipate impairments in blood flow to the brain will be predictive of reduced cognitive performance, revealing a potential disease-, sex-, hormone-specific cause of heightened dementia risk.