What is heart disease?

Coronary Artery Disease (CAD) is the most common type of heart disease. Over time, progressive narrowing of the heart’s blood vessels can lead to a heart attack and/or heart failure. Once someone has a heart attack, intervention at a hospital, whether by a cardiac surgeon or interventional cardiologist, should be performed as quickly as possible. While a heart attack itself must be dealt with as urgently as possible (cardiologists like to say “time is muscle”), heart disease is a chronic condition that develops over decades.

What are the risk factors for this type of heart disease?

• Age
• Family history 
• Genetics
• Lifestyle choices  

At what age is heart disease usually diagnosed?

With the exception of individuals with rare monogenic mutations, coronary heart disease does not usually result in a myocardial infarction (MI) or “heart attack” until someone is, at the earliest, in their 40’s and 50’s– eg, the average age at first heart attack is 65.6 years old for men and 72.0 for women.

How does my family history impact my risk for heart disease?

A Danish population registry study following 4.4 million people found that having at least one 1st-degree relative (parent or sibling) with a history of a heart attack increases someone’s risk of a heart attack by 1.52 fold. The risk increased the younger the age at which a relative experienced an MI and the more relatives that were affected.

How do my genetics impact my risk for heart disease?

The heritability of coronary artery disease is estimated to be between 40% and 60% based on an analysis of 20,966 twin pairs drawn from the Swedish Twin Registry. Orchid’s GRS for CAD includes 1,107,562 variants and was developed based on the variants identified in a study that analyzed genomes of about 184,000 individuals of European ancestry affected by CAD. Orchid’s GRS does not cover the traditional monogenic causes of heart disease like familial hypercholesterolemia, which occurs in about 0.4% of the population. 

Is there anything I can do to reduce my child’s risk of developing heart disease?

As explained in the coronary artery disease whitepaper, genetics plays an important role in determining the risk of coronary heart disease. Using Orchid’s embryo screening scoring, you can prioritize the embryo with the lowest genetic risk profile for heart disease and potentially reduce their risk of coronary artery disease.  

Is there anything I can do to reduce my risk of developing heart disease?

These can be classified into three buckets:

1. Lifestyle interventions
2. Pharmaceutical interventions
3. Gathering data through biomarkers or imaging 

What lifestyle changes can I make to reduce my risk of developing heart disease?

Quit smoking

The most significant risk factor under your control is smoking. Quitting smoking reduces risk. 

Reduce elevated blood pressure levels

Next, monitoring and managing high blood pressure. High blood pressure is defined as > 130/80 BP, and should be checked annually at a physical. If you have high blood pressure, reduce your salt intake to less than 2400mg/day and perform aerobic exercise 3-4x/week, 40 minutes each session. 

Eat less saturated fats

Third, lower your LDL cholesterol (“bad cholesterol”) levels through reducing your consumption of saturated fat. 

Get your BMI under 30

Fourth, maintain a healthy weight: if your BMI is more than 30, sustained weight loss of at least 5% will tend to improve cholesterol and blood pressure.  

What medications are used to manage heart disease?

Risk factors like high blood pressure and high LDL cholesterol can be controlled with a variety of medications. Managing medical conditions that raise your risk, like diabetes, are also important. These medical interventions have excellent evidence for their use in high-risk adults. 40+ is typically the age range where doctors consider starting these medications as there is limited evidence for use in younger people. In all likelihood, your doctor may be reluctant to start you on medication if you’re under 40, unless one of your risk factors is very concerning or you have a strong family history of heart disease. 

What labs or imaging are available to monitor my risk of heart disease?

Orchid’s genetic risk score provides some information about your heart attack risk, but you may want to learn more. Some options include:

1. The USPSTF recommends checking blood lipid levels in most adults at least once. Some doctors may recommend testing with more advanced lipid tests.
2. A Coronary Artery Calcium (CAC) score can be used to estimate how much coronary artery disease a person already has and is most useful in the risk stratification of intermediate risk patients. At this point, the utility is unclear in  healthy patients under 40 years of age.

What are some symptoms of heart disease?

Some people don’t experience any symptoms from heart disease until they have a heart attack, which is why doctors check risk factors and do diagnostic testing after a patient reaches a certain age. Others experience chest or left arm/shoulder pain when exercising, shortness of breath, or atypical (especially in women and diabetics) symptoms like nausea.  

To check if a patient already has coronary artery disease, or to assess symptoms, such as recurring chest pain while exercising (“stable angina”), cardiologists have various tests they can run:

1. Exercise stress test
2. Coronary artery calcium (CAC)
3. Echocardiography
4. Coronary Computed Tomography Angiography (CCTA)
5. Stress Cardiac Magnetic Resonance Myocardial Perfusion Imaging
6. Stress/Rest Myocardial Perfusion Imaging 
7. Invasive Coronary Angiography 

Some of those, like invasive coronary angiography, carry small but real risks, so they’re typically performed only after noninvasive tests, like an exercise stress test, are performed and found to be abnormal or suggestive of coronary artery disease.

How is heart disease diagnosed? 

In patients that aren’t having a heart attack or concerning symptoms but want to check if they have signs of heart disease, a primary care physician or cardiologist will start off by getting more information about a patient's risk factors. They’ll check blood lipids, blood pressure, and HbA1C (a marker of diabetes). All that information is used to better understand how likely someone is to have a heart attack in the next 10, 20, or 30 years.

How do doctors estimate risk of heart disease?

Some groups, like South Asians, have higher rates and earlier onset of heart disease even after adjusting for risk factors, which is not captured in traditional risk calculators. Doctors and patients have a variety of tools to reduce (not eliminate) the risk of a heart attack and/or delay it. 

These interventions are possible because doctors have amassed a wealth of knowledge on the risk factors for heart disease and lifestyle and medical tools to target them. Here is a calculator developed by the American College of Cardiology as a risk-assessment tool to give you an idea of what doctors look at.

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 A downside of the ASCVD calculator is that it lacks the ability to take into account family history of heart disease. Like most traits, heart disease is a mix of genetic and environmental influences, and so Orchid’s genetic risk score can tell you something about your risk that doesn’t show up in most traditional heart attack risk calculators.  

Official medical guidelines have not quite caught up with these developments. A recent set of recommendations from the American Heart Association states the following: 

“limited data exist on the performance and utility of 10-year risk estimation tools….Because age is a major driver of risk, most in this age range (<40 years) are unlikely to have a sufficiently elevated 10-year risk to warrant pharmacological therapy…Nevertheless, periodic assessment of risk factors (eg, at least every 4 to 6 years in younger adults 20 to 39 years of age) is important to guide discussions about intensity of lifestyle interventions, frequency of risk factor monitoring, treatment of nonlipid risk factors, and consideration of 30-year or lifetime risk estimation.” 

Translated into plain English, they state that because little data exists for younger people interested in reducing their risk of heart disease, and because young people in general have a much lower risk of heart disease, there are no extremely firm medical next steps for reducing cardiovascular risk. So any advice in this guide is, by necessity, somewhat speculative. With that caveat in mind, there are a variety of tools that a preventative cardiologist or primary care physician might recommend or prescribe to reduce heart disease risk.

How is a heart attack diagnosed?

In emergency settings, when patients have acute symptoms that may be from a heart attack, doctors will perform an electrocardiogram (EKG) and check the blood for certain markers. Characteristic changes in the electrical signals of the heart (such as a ST Elevations) picked up by an EKG occur with large heart attacks referred to as ST Elevation Myocardial Infarctions or “STEMI”. Markers in the blood, like cardiac troponin, rise when heart muscle is damaged or dies from lack of blood flow. If either is positive, a myocardial infarction has occurred and doctors will intervene, whether it be surgically, endovascularly, or medically.

Takeaways

1. Coronary Heart Disease is a chronic disease that develops over decades.
2. There are medical and lifestyle interventions with good evidence for reducing risk:

                 1. quitting smoking and losing excess weight
                 2. controlling high blood pressure, high LDL cholesterol, and diabetes

3. Ask your preventative cardiologist about your 30-year risk or lifetime risk of cardiovascular disease

Where can I learn more?

1. A podcast episode between Dr. Allan Sniderman and Dr. Peter Attia on cardiovascular risk factors, the genetic evidence for LDL cholesterol’s role in heart disease, and early intervention.
2. A provocative piece by Dr. Eugene Braunwald, a well-known academic cardiologist, on “How to Live to 100 before Developing Clinical Coronary Artery Disease.

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