Link Between Cardiovascular Disease Markers and Microscopic Strokes
Study Overview
In a 2017 study published in JAMA Neurology, researchers investigated the relationship between cardiovascular disease markers, specifically N-terminal pro-brain natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (hs-cTnT), and cortical cerebral microinfarcts (CMIs), which are microscopic strokes in the brain’s cortex. The study revealed that these cardiovascular markers are linked to CMIs, independent of other vascular disease risk factors.
Significance of Cortical Cerebral Microinfarcts
Cortical cerebral microinfarcts are small strokes that occur in the outer layers of the brain, areas crucial for high-level functions such as cognition, language, and memory. They have gained attention as potential indicators of vessel-related diseases in the brain, contributing to cognitive impairment and dementia. Understanding the connection between NT-proBNP, hs-cTnT, cardiovascular disease, and CMIs may lead to new treatment and prevention strategies for cardiovascular diseases and related cognitive impairments.
Study Methodology
Participants in the study were recruited from two memory clinics in Singapore and classified into groups based on cognitive status: no cognitive impairment, cognitive impairment without dementia, vascular cognitive impairment without dementia, Alzheimer’s disease, vascular dementia, or mixed dementia. Data on demographics, including age, sex, race, educational level, and smoking history, were collected through questionnaires. Medical histories concerning atrial fibrillation, ischemic heart disease, congestive heart failure, high blood pressure, high cholesterol, and diabetes were verified through medical records. Physical examinations assessed height, weight, and blood pressure, while blood samples were taken to measure NT-proBNP and hs-cTnT levels.
Brain imaging was conducted using 3-T magnetic resonance imaging (MRI) to identify and grade cortical and lacunar infarcts, along with microscopic bleeding. Magnetic resonance angiography was used to evaluate the narrowing of blood vessels that could lead to strokes.
Study Findings
Of the 464 participants recruited, 243 were included in the final analysis after excluding 221 due to undetectable NT-proBNP or hs-cTnT levels or lack of gradable CMIs. Among the 243 participants, 70 (28.8%) had at least one CMI, while 36 (51.4%) had one CMI, 20 (28.6%) had two to four, and 14 (20%) had five or more. Participants with CMIs exhibited a higher prevalence of non-CMI lacunar and cortical infarcts, microscopic bleeding, and narrowed blood vessels compared to those without CMIs. Notably, elevated levels of NT-proBNP and hs-cTnT were significantly associated with an increasing number of cortical CMIs.
However, this correlation was not observed in individuals without cardiovascular disease who had three or more CMIs. Additionally, factors such as atrial fibrillation, ischemic heart disease, and congestive heart failure were linked to cortical CMIs, regardless of other cardiovascular risk factors.
Conclusions and Future Directions
The study identified elevated levels of cardiovascular disease markers associated with microscopic strokes in the brain’s cortex, independent of vascular risk factors. This suggests that underlying pre-clinical conditions leading to increased NT-proBNP and hs-cTnT levels, such as heart muscle injury or overstretching, may contribute to the development of CMIs. However, the study did not explore the temporal relationship between NT-proBNP and hs-cTnT levels, the prevalence of cardiovascular conditions, and the development of CMIs over time, precluding causal conclusions.
The imaging technique utilized, 3-T MRI, may not have been sensitive enough to detect CMIs smaller than 2 mm. Future research may benefit from employing higher-resolution imaging techniques, such as 7-T MRI. Exploring the relationship between NT-proBNP and hs-cTnT levels, cardiovascular disease, infarct size, and cognitive impairment could provide valuable insights. Furthermore, therapeutic strategies aimed at reducing NT-proBNP and hs-cTnT levels may prove useful in preventing CMIs.
Author
Written By: Raishard Haynes, MBS