Heart Attack And Diabetes

Overview

There are various risk factors responsible for someone having a heart attack. One of these factors is diabetes. Diabetes results in high levels of glucose in the blood, which can cause damage to blood vessels. This damage can prevent blood flow to the heart, causing heart attacks. 

Understanding heart attack and diabetes

Whilst there is a link between heart attacks and diabetes, it’s important to understand their pathophysiology as separate entities to fully grasp exactly how they are linked.

About heart attack

So what exactly is a heart attack? Simply put, a heart attack is when the heart tissue is not receiving adequate blood flow due to a blockage in the blood vessels. This means that it isn’t receiving enough oxygen and therefore is not able to function properly. This lack of oxygen can result in the heart tissue becoming damaged (ischaemic injury) or even dying (infarct). In medical terms, a heart attack is commonly referred to as myocardial infarction (MI). 

About diabetes

Diabetes is a condition that results in high blood sugar, also referred to as blood glucose levels. There are various types of diabetes, with various causes. The type of diabetes that is most commonly referred to is diabetes mellitus, which is further classified into two types:

• Type 1 diabetes mellitus - usually present from a young age and is commonly due to an inability to produce insulin due to autoimmune processes
• Type 2 diabetes mellitus - usually develops later in life and is commonly due to decreased sensitivity to insulin or a reduction in the amount of insulin produced 

Insulin is a hormone that is produced by the pancreas. It plays a key part in regulating blood sugar levels. It does this by acting as a key for cells to let in sugar that is circulating in the blood. Insulin opens the door to the cell, thereby allowing the glucose to exit the blood and enter the cell. If there is no insulin present then the door remains closed and glucose remains locked out, roaming in the blood. If there is decreased insulin sensitivity this means that although the doors are opening, they are not opening as easily as they used to. The key isn’t fitting into all the locks that it should, therefore only part of the blood glucose can enter the cell. 

Other types of diabetes include:

• Gestational diabetes - this occurs in pregnant women and usually resolves once they have given birth.
• Diabetes insipidus - due to a hormonal imbalance caused by the brain.
• Mature onset diabetes of the young (MODY) - passed on genetically.
• Neonatal diabetes - usually a genetic cause leading to a lack of insulin production following birth.
• Steroid-induced diabetes - occurs due to steroids affecting the hormone production within your body.
• Secondary - diabetes can occur secondary to a different condition in your body e.g. pancreatitis, cystic fibrosis, pancreatic cancer etc. 

Heart attack and diabetes: The connection

So we understand what heart attacks are, and what diabetes is. But what’s the link? Why does having high blood sugar increase your risk of having a cardiovascular event like a heart attack? 

Can diabetes cause a heart attack?  

Diabetes itself doesn’t cause heart attacks, although having diabetes does increase your risk of having a heart attack. There are various other risk factors for having a heart attack as well, including:

• Coronary heart disease
• High blood pressure
• Heart failure
• Vascular disease
• Family history of cardiovascular disease
• Sedentary lifestyle
• High fat percentage in your body composition
• High cholesterol levels
• Smoking 
• Excessive alcohol intake

How does diabetes increase the risk of having a heart attack?

The most common cause of a heart attack is underlying coronary heart disease.¹ This occurs when there has been damage to the vessel wall of the coronary arteries. The body responds and tries to heal this area, leading to the formation of a clot. This is similar to when you get a scab forming over a wound. This clot is internal, however, and therefore the process is slightly different. The clot is quite sticky, and as a result of this, things that flow by in the bloodstream can also become ‘stuck’ onto the clot as it is forming. This results in the formation of a plaque. If this gets too big then it can cause occlusion of the vessel. Alternatively, a piece of this plaque might break off into the blood flow. This can then travel and become lodged elsewhere, causing a blockage at a site different to the site where the clot formed.  

It’s important to remember that diabetes can lead to other conditions as well. One of these is damage to the nervous system. As a result of this, diabetic patients may notice that they have decreased sensation (diabetic neuropathy). This is most notable in the feet, although it can also affect the heart. If there is damage to the nerves supplying sensation to the heart it is possible for diabetic patients to have a silent heart attack. This means that they might not feel any chest pain, despite having a heart attack. This is important to remember, as when we talk about heart attacks, the symptom we most often associate with them is usually chest pain. As such it is important for diabetic patients to be aware of other warning signs of a heart attack, such as:

• An ache or dullness in the chest that won’t resolve. This can feel like pressure or fullness in the chest
• Fatigue
• Exercise intolerance
• Shortness of breath and difficulty breathing

Prevention and treatment

Every health condition has two broad categories for risk factors: ones you can change and ones you can’t. What can we do to reduce the risk of suffering a heart attack? 

Lifestyle changes

• Maintain a physically active lifestyle. The British Heart Foundation recommends that adults should get a minimum of 2.5 hours of activity in the week²
• Stop smoking
• Reduce your alcohol intake

Natural ways

• Reduce the amount of salt in your diet - the maximum recommended is 6g/day³
• Reduce the amount of saturated fats in your diet
• Eat foods that help to keep your cholesterol levels within a healthy range

Medications

Due to cardiovascular health being reliant on various factors, it is important to optimise treatment for any conditions that you have. It is therefore essential that you seek medical advice for the treatment of any underlying conditions. Examples include:

• Diabetic control - there are various medications available to help control your blood glucose levels, the right one will depend on your type of diabetes and be monitored by your response to the treatment options.
• Managing your blood pressure - if you have high blood pressure this also increases the risk of damage to the blood vessels.
• Managing coronary artery disease - if there are concerns about your cardiovascular health your doctor may prescribe medication to help your heart. 
• Statins - these can be used to reduce cholesterol levels if your cholesterol levels are high, or if you are in a high-risk category.

Summary

Heart attacks and diabetes are linked in the sense that having diabetes can increase your risk of having a heart attack. This is largely due to damage to vessels that results from high blood sugar levels. It’s important to remember that heart attacks can present slightly differently in diabetic patients as they can be silent heart attacks. The best way to minimise the risk is to make lifestyle changes and optimise the treatment of any medical conditions that you already have. 

If you have any suspicion that you may be suffering a heart attack it is important to seek medical attention straight away.