How to Identify Risk for Cardiovascular Disease Using ApoB/ApoA1 Blood Testing

"You’re at risk for a cardiac event….”

One of the most dreadful statements a doctor can make to a patient. In a world full of processed foods and sedentary lifestyles, cardiac health catches most patients off guard.

As a practitioner, you advocate for patients to eat healthy, stay active, and not smoke. Yet, each of us knows a story of someone who religiously followed this advice but still experienced a heart attack.

It’s tragic. But there’s hope.

The ApoB/ApoA1 ratio is an effective predictor of coronary heart disease. It can be calculated with a simple blood test that compares the concentration of the low-density lipoprotein (Apolipoprotein B) and the high-density lipoprotein (Apolipoprotein A1.)

When the ratio is above the desired value of 0.6, it’s a strong indicator of risk for cardiovascular disease. Continue reading to learn how to use this test in your clinic.

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Understanding Cholesterol

To understand why these two proteins can provide us with such valuable information, it is important first to understand the commonly misunderstood topic of cholesterol. I have found that, for many patients, all they know about cholesterol is high cholesterol equals bad and low cholesterol equals good. But it’s not as simple as that.

Cholesterol is an organic compound that is a necessary component used by your body to create things such as hormones, vitamin D, and even certain compounds needed for digestion. Yet, problems begin to arise when our body has more of certain types of cholesterol than is necessary to create these various compounds.

The Importance of Lipoproteins

Cholesterol, all by itself, cannot dissolve in the blood. It must be carried through the bloodstream by transporters called lipoproteins (Lipoproteins = Lipids + Proteins). Testing lipoproteins show varying patterns that correlate with the risk of having a fatal cardiovascular event. High LDL, VLDL, and triglyceride levels are associated with an increased risk of atherosclerosis and heart disease. High HDL is correlated with reduced cholesterol levels and lower cardiovascular risk.

Understanding the ApoB/ApoA1 Proteins

Apolipoprotein A1 (ApoA1) is the primary protein associated with “Good Cholesterol” high-density lipoprotein (HDL) particles. ApoA1 grabs excess cholesterol throughout the body and delivers it directly to the liver. ApoA1 is often interpreted as a ratio with apolipoprotein B (ApoB).

Apolipoprotein B (ApoB) are proteins found in lipoprotein particles that are artery-clogging. “Bad Cholesterol” (LDL) will form with a protein to send the excess cholesterol directly to the arteries, where it can bind with other molecules in the body to form a plaque that coats our blood ways. Each bit of plaque makes it that much harder for your heart to pump blood throughout the body.

To truly understand why ApoB/ApoA1 is a better measure of cardiovascular risk than simply using an LDL-Cholesterol or HDL/LDL ratio as a marker, we have to go a layer deeper and look at the multiple types of LDL.

LDL-Cholesterol: The Four Types

There are four subclasses of LDL-Cholesterol, which are labeled LDL I-IV. The smaller the size and greater the density of an LDL molecule, the more dangerous it is to cardiovascular health. These harmful LDL molecules, which fall under the LDL III and LDL IV labels, are described as small-dense LDL (sd-LDL).

The main issue that we run into when simply testing LDL-Cholesterol levels is that each particle contains different levels of cholesterol, and this value does not tell us which subclass of particle we are dealing with.

Your body more easily removes the less dense LDL particles, so by including them in LDL-cholesterol values, you gain an inaccurate picture of the actual cardiovascular risk. On the other hand, the sd-LDL are the main culprits in the creation of atherosclerotic plaque.

The simplest way to combat this misrepresentation is by looking at the total number of LDL particles instead of total LDL-cholesterol value. The more total particles the more sd-LDL particles there are in the body, and therefore the greater the cardiovascular risk.

Since there is a single ApoB in each LDL particle, we can use that value to determine the number of LDL particles, and therefore the actual cardiovascular risk without having to pursue more specialized tests.

This is why the ApoB/ApoA1 ratio allows a provider to understand exactly how much “good” versus “bad” cholesterol you currently have in your body, and the moment that the amount of bad cholesterol begins to rise above the good cholesterol is the moment that you are at risk.

Luckily, by keeping a watchful eye on this ratio, and seeing how various types of exercise or diets affect it, a doctor can identify exactly what kind of fitness and nutrition regimen will be the best for you as an individual.

The difficulty lies in the fact that no two patients are the same. An ideal diet and exercise regimen for one patient may not work for another patient. The only way to know which works best is trial and error, but with access to such invaluable information such as your ApoB/ApoA1 ratio, providers are able to guide their patients to a place where the heart attack (and other cardiovascular events) don’t seem nearly as frightening.