Hidden brain changes discovered in people with heart disease

Did you know that heart problems can secretly cause changes in your brain? It may sound scary, but these changes can put you at an increased risk for serious health issues like stroke and dementia.

While your heart health might be the focus, don’t let your brain health fall to the wayside.

Brain blood vessels change after heart issues

A new study by the George Institute for Global Health reveals a surprising connection between heart disease and unseen changes in brain blood vessels.

The implications are a little frightening: these changes make deciding on safe treatments for heart patients complicated and may raise their risk of complications like brain bleeds.

“Although people with heart disease are two to three times more likely than the general population to have changes in their brain’s vascular system, they’re often overlooked, because these patients don’t routinely undergo brain imaging unless they have suffered a stroke,” said Dr. Zien Zhou, the study’s lead author.

Signs of brain changes due to heart disease

So, what are these sneaky changes we should look out for? Here’s a rundown:

Silent brain infarctions (SBIs)

Silent Brain Infarctions, or SBIs, are essentially “silent strokes.” They occur when there is a disruption in the blood flow to a part of the brain, causing tissue damage.

Unlike typical strokes, SBIs often go unnoticed because they don’t cause any immediate, noticeable symptoms. Over time, however, they can accumulate, leading to cognitive decline and increasing the risk of future strokes.

Cerebral small vessel disease (CSVD)

Cerebral Small Vessel Disease encompasses a range of conditions affecting the small blood vessels in the brain, including the arterioles, capillaries, and venules.

These vessels can become damaged or blocked over time, leading to reduced blood flow to various parts of the brain.

CSVD is a common cause of stroke and dementia, particularly in older adults. It can also contribute to the development of white matter lesions and lacunes.

Lacunes

Lacunes are small, cavity-like spaces that form in the brain as a result of brain tissue death, usually due to a lack of blood supply related to small vessel disease.

These cavities can be considered a subtype of silent infarcts but are specifically linked to chronic damage from high blood pressure and other vascular risk factors.

Lacunes bring a range of clinical effects into play, ranging from being asymptomatic to causing cognitive and motor impairments.

White matter lesions

White matter lesions (WMLs) are areas of damage or degeneration in the brain’s white matter, where the myelin sheath covering nerve fibers is compromised.

This damage disrupts the normal transmission of electrical signals between different parts of the brain and between the brain and the rest of the body.

WMLs are associated with aging, hypertension, and vascular risk factors, and their presence can predict a higher risk of stroke, dementia, and physical disability.

Microbleeds

Microbleeds are tiny areas of bleeding within the brain tissue, often found in association with cerebral small vessel disease.

They are considered markers of blood vessel pathology and can be indicative of an increased risk of larger brain hemorrhages.

Microbleeds can be symptomatic of an underlying vulnerability in the brain’s vascular system and are linked to cognitive decline and an increased risk of stroke.

Brain atrophy

Brain Atrophy refers to a reduction in brain volume, which can result from the loss of neurons (brain cells) and the synaptic connections between them.

This process can be part of the natural aging process but may also accelerate due to neurological diseases, such as Alzheimer’s disease, or as a consequence of chronic cerebral small vessel disease.

Brain atrophy can lead to significant cognitive and functional impairments, depending on which areas of the brain are affected.

Brain changes and heart disease risk

This study paints a clear picture. Here’s what it found in people with heart diseases like atrial fibrillation, heart failure, and others:

• About one-third had SBIs.
  
• One-quarter had lacunes.
  
• Two-thirds had white matter lesions.
  
• One-quarter had evidence of microbleeds.
  
• Over half had brain atrophy.

What’s causing these dangerous brain changes?

Scientists think the causes lie in the shared risk factors between heart disease and brain problems like:

Aging

Scientists pinpoint aging as a primary factor that contributes to both heart disease and brain changes. As we age, our bodies undergo various physiological changes that can affect the health of our blood vessels.

These changes can lead to a reduced capacity of the vessels to supply blood efficiently to the heart and brain, increasing the risk of conditions like silent brain infarctions and cerebral small vessel disease.

The natural wear and tear on the body over time make aging a significant risk factor for these health issues.

High blood pressure

High blood pressure, or hypertension, is identified as a critical cause of both heart conditions and adverse brain changes. It exerts extra force against the walls of your arteries, leading to damage over time.

This damage can restrict blood flow to the heart and brain, contributing to the development of conditions such as white matter lesions and microbleeds.

Hypertension is especially notorious for its role in exacerbating cerebral small vessel disease, making it a key area of concern for researchers.

Diabetes

Diabetes, particularly type 2, plays a substantial role in the onset of heart disease and brain alterations. High levels of glucose in the blood can lead to damage in both large and small blood vessels, impairing the flow of oxygen and nutrients to the heart and brain.

This can accelerate the process of brain atrophy and increase the risk of silent brain infarctions. The metabolic disturbances caused by diabetes further exacerbate the vulnerability of the brain’s vascular system.

High cholesterol

High cholesterol is another shared risk factor that contributes to dangerous changes in both the heart and brain. Cholesterol buildup can lead to the formation of plaques in the arteries, narrowing them and making it harder for blood to flow through.

This can decrease the blood supply to the brain, leading to conditions like lacunes and contributing to the overall risk of stroke and dementia. Managing cholesterol levels is thus crucial for preventing both heart disease and the associated brain changes.

Smoking

Smoking is a well-established risk factor for a multitude of health problems, including heart disease and brain changes.

The chemicals in tobacco smoke can damage blood vessels, leading to atherosclerosis (the buildup of fatty substances in the arteries) and an increased risk of blood clots.

This damage can significantly impair blood flow to the brain, contributing to the development of silent brain infarctions, cerebral small vessel disease, and other vascular changes.

Quitting smoking is one of the most effective steps individuals can take to reduce their risk of these conditions.

Dr. Zhou explains, “It’s possible that a gradual decline in cardiac output in some patients with heart disease might affect how much blood is reaching the brain tissue, contributing to vascular changes and cognitive dysfunction in these patients.” Tiny blood clots forming in the heart and traveling to the brain are another possible culprit.

Treating brain changes linked to heart disease

“It can make them more susceptible to the risk of brain bleeds from medications 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 percent,” warns Dr. Zhou.

This leaves doctors in a dilemma – the very medications that protect the heart could be dangerous to the brain.

Addressing the link in heart and brain changes

The study emphasizes the urgent need to understand exactly how and why these brain changes are triggered by heart disease.

More importantly, can we find ways to safely manage the risks in these patients?

• MRI Scans: Should it be routine to perform MRI scans on people with heart disease before starting blood thinners? Right now, it’s a question that needs answering.

Your heart and brain are an intricately linked duo. If you have heart disease, understanding how it affects your brain health is crucial for making safe, informed treatment decisions.

The full study is published in the journal Neurology.

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