Although the researchers were able to find an association between a heart attack and faster cognitive decline, the findings did not establish that a heart attack directly causes cognitive decline.
Preventing heart attacks may help slow cognitive decline, according to preliminary research to be presented at the American Stroke Association’s International Stroke Conference 2022. This study is one of the first to examine both the short- and long-term impact of a sudden cardiac event on mental cognitive abilities, according to the study authors.
“We need to realize that what’s going on in the heart and brain are related. Managing risk factors to prevent a heart attack is actually good for your brain as well,” said lead study author Michelle C. Johansen, MD, PhD, an assistant professor of cerebrovascular neurology at the Johns Hopkins University School of Medicine, in a press release. “We have shown that having a heart attack can be detrimental to your brain health over time.”
The research team analyzed data from 6 long-term studies conducted between 1971 and 2017: Atherosclerosis Risk in Communities Study; Coronary Artery Risk Development in Young Adults Study; Cardiovascular Health Study; Framingham Offspring Study; Multi-Ethnic Study of Atherosclerosis; and Northern Manhattan Study. There were 31,377 study participants with a median age of 60 years at the time of the first cognitive assessment.
Study participants could not have had a heart attack or have been diagnosed with dementia. A team of neuroscientists and statisticians synced data prior to the current analysis to adjust for differences among the study groups and the cognitive measure screening methods.
Cognitive tests were categorized into 3 areas:
The results were adjusted for multiple demographic factors, heart disease risk factors, and cognitive test results prior to a heart attack. Additionally, the study participants who had a stroke during the follow-up period were no longer included in the analysis because stroke can impact cognition.
During the time in which the participants were followed, 1047 had a heart attack. These participants did not show a significant decline in any measure of cognition soon after the time of the heart attack when accounting for demographics and vascular risk factors. However, they did show significantly faster declines in memory, executive functioning, and global cognition in the years that followed the heart attack.
“Dementia is a slow, step-wise process. One doesn’t wake up out of the blue with dementia. If a heart attack is a factor in the development of dementia, you would not anticipate that after adjusting for how sick a patient is that there would be cognitive decline immediately, however, we did find the significant change occurs several years later,” Johansen said in the press release. “It’s important to know that cognitive decline is a possibility after a heart attack, so physicians are both managing patients’ heart disease and looking for signs of dementia following a heart attack. It can even be a great conversation-starter about why it’s important for patients to follow medical advice to prevent a heart attack.”
Additional research is needed to identify the mechanisms that are involved in differentiating a heart attack and cognitive decline, according to the study authors. Several mechanisms were previously noted from the research team, such as ongoing damage to the brain from silent strokes; shared risk factors for heart attack and dementia; and a heart attack that could change the structure of the heart, increase the risk of mini-clots going to the brain, and reducing oxygen reaching the brain.
“For too long, we have thought about and addressed heart disease and brain disease as two separate conditions, and based on our study’s findings and other research, I don’t think we’re going to be able to keep doing that as we learn more,” Johansen said in the press release.
Although the researchers were able to find an association between a heart attack and faster cognitive decline, the findings did not establish that a heart attack directly causes cognitive decline. One limitation of the study was that it only took in the United States, which could make prevent the findings from being generalizable to people in countries with less access to medical care.
“The impact of a heart attack on cognitive function may turn out to be worse in places that don’t have access to things like blood pressure medications and statins to control disease after a heart attack. We don’t know, yet it is definitely something to think about, and it emphasizes the importance of preventing and treating heart attack worldwide, not simply in the United States,” Johansen said in the press release.
Cognitive skills declined faster in the years after a heart attack. American Heart Association. February 3, 2022. Accessed February 3, 2022. https://newsroom.heart.org/news/cognitive-skills-declined-faster-in-the-years-after-a-heart-attack?preview=b9b7