A study found a high prevalence of changes in the brains of people with heart disease

A new review of more than 13,000 people has found that changes to blood vessels in the brain, which can increase the risk of stroke and dementia, are common in people with a range of heart conditions, regardless of whether they have or not a stroke.

New research, published Wednesday in the April issue of the journal Neurologyis the most comprehensive systematic review to date of the “hidden” changes that occur in the brain in people with a range of heart conditions.

Lead author Dr. Zien Zhou of the George Institute for Global Health said identifying these changes could play an important role in choosing treatments for these patients.

“Although people with heart disease are two to three times more likely than the general population to have changes in the cerebrovascular system, they are often overlooked because these patients do not routinely undergo brain imaging unless they have suffered a stroke”, he said in a press release from the Institute.

This, the researcher says, may make these patients more susceptible to the risk of brain hemorrhages caused by drugs commonly used to treat or prevent blood clots.

Intracranial hemorrhage is a life-threatening complication with no proven treatment and a survival rate of less than 50%, according to experts.

Changes in blood vessels in the brain that can only be detected by brain imaging, such as silent cerebral infarction (SBI) and cerebral small vessel disease (CSVD), are known to occur more frequently in the elderly or those with hypertension arterial.

Although not enough to cause overt neurological symptoms, these changes can lead to subtle neurological deficits and increase the long-term risk of stroke or dementia.

To determine the prevalence of these hidden or disguised cerebrovascular changes in adults with atrial fibrillation, coronary artery disease, heart failure or cardiomyopathy, valvular heart disease, and patent foramen ovale (a hole in the heart), George Institute researchers conducted a meta-analysis of 221 observational studies published between 1988 and 2022.

The findings showed that in people with heart disease:

• about a third had some form of silent stroke;
• a quarter had lacunae (small cavities where neural tissue has died after a previous blockage or leakage from small arteries);
• two-thirds had white matter damage (damage to the protective covering around nerve fibers/demyelination);
• a quarter had evidence of symptomatic microbleeds in the brain tissue;
• more than half had cerebral atrophy (shrinking of the brain due to loss of neurons or connections between neurons);

The prevalence of these brain changes was generally the same between those with and without a recent stroke, and there were no apparent gender differences in outcomes.

According to Dr. Zhou, the study also confirmed that heart disease is one of the main causes of these changes, reflecting the “fragility” of the brain.

“Although several potential mechanisms have been proposed for the association between heart disease and occult cerebrovascular injury, the two conditions share common risk factors such as aging, hypertension, type 2 diabetes, hyperlipidemia, and smoking,” said Dr. .Zhou.

He also stated that it is possible that a gradual decrease in cardiac output in some patients with heart disease affects the amount of blood reaching brain tissue, contributing to vascular changes and cognitive dysfunction in these patients.

“It is also possible that hidden brain changes and cognitive dysfunction are a consequence of small blood clots traveling to the brain through the arterial circulation after forming in the heart,” he notes, adding that more is needed research to analyze the exact causes of these brain changes and the implications for the management of these patients.

“We need to know whether performing an additional MRI in those being considered for anticoagulant therapy — which is necessary for most people with heart disease — would be cost-effective in terms of preventing unwanted side effects,” he said.

He also pointed out that refining the risks of brain clots and bleeding from anticoagulants and using this information to make the best treatment choice could improve the safety of treatment for people with heart disease.

The George Institute for Global Health is an independent medical research institute based in Australia with offices in China, India and the UK. The institute conducts research on non-communicable diseases, including heart and kidney disease, stroke and diabetes.