Cerebral blood flow is rigorously regulated by various mechanisms to safeguard the match between cerebral metabolic demand and supply. The question of how a change in heart health affects cerebral blood flow is fundamental, because cerebral blood flow receives a significant proportion of cardiac output. Overall studies have shown that an alteration in cardiac output, either acutely or chronically, leads to a change in cerebral blood flow with more study needed to improve patient outcomes. Now, a study from researchers at Erasmus University has identified a connection between very early stages of brain and heart disease. The team state that to their knowledge, this study is the first to demonstrate an association between NT-proBNP, which is used to detect heart failure and the microstructure of the brain. Results of their study were presented at the annual meeting of the Radiological Society of North America (RSNA).
Heart and brain diseases are big problems in aging individuals and are expected to grow even more. It is known that myocardial infarction, heart failure and atrial fibrillation are associated with an increased risk of stroke and dementia. And that a change cerebral blood flow is affected by cardiac output, independent of other cerebral blood flow-regulating parameters including blood pressure and carbon dioxide. However, studies on the association between heart health and cerebral blood flow in patients with varying neurologic, medical, and surgical conditions have, in the past, been confounded by methodologic limitations. The current study investigates whether the heart-brain link is present at an earlier stage of disease.
The current study analyzed data from 2,432 participants, 57.4% of which are women with a mean age of 56.6 years); participants with overt heart disease, dementia and strokes were excluded from the analysis. The participants underwent brain MRI, which included the use of an advanced technique called diffusion tensor imaging, and blood testing to measure levels of N-terminal pro b-type natriuretic peptide (NT-proBNP), which is primarily used to help detect, diagnose and evaluate the severity of heart failure.
The lab explain that NT-proBNP is released into the bloodstream in response to myocardial wall stress with studies demonstrating that this biomarker provides information on cardiac dysfunction even in the absence of overt heart disease. They go on to add that diffusion tensor imaging provides information on the microstructural organization of the brain’s white matter; it is thought that microstructural brain changes precede white matter lesions. Brain MRI results were also analysed for markers of early brain disease, including a loss of brain volume, microstructural changes and white matter lesions, which indicate areas of cells that have been damaged by injury or disease.
Results show that participants with higher NT-proBNP levels had worse microstructural organization within the white matter. Data findings show that higher NT-proBNP levels were also associated with smaller total brain volume and larger white matter lesion volume, with the brain volume lost predominantly in the gray matter.
The team surmise that their findings show that the heart and brain are intimately linked, even in presumably healthy individuals. For the future, the researchers state that these methods could be used to inform clinicians about the development of disease as a person ages.