- Atherosclerosis involves a buildup of plaque in the blood vessels. It can lead to complications like heart attack and stroke.
- Screening for components contributing to atherosclerosis, such as cholesterol levels, is vital in preventing adverse cardiovascular outcomes.
- A recent study found that testing for a specific protein, apolipoprotein B-100 (ApoB), may be a more accurate method of predicting atherosclerotic cardiovascular disease risk than testing for cholesterol levels alone.
The health of the heart and blood vessels is vital to body function. Early screening can help people understand their risks and potentially prevent adverse health outcomes.
Testing cholesterol levels is important, but another test can further help identify the risk for cardiovascular disease: apolipoprotein B-100 (ApoB) levels. This protein helps transport cholesterol throughout the body.
Testing for the level of this protein in the blood may help identify people who are more at risk for cardiovascular disease, even when cholesterol levels are normal.
This is the argument that a team of researchers from Intermountain Healthcare — a system of 33 hospitals in Utah — have made at the 2023 American College of Cardiology annual Scientific Sessions (ACC23) in New Orleans.
The researchers’ presentation was based on an analysis they had recently conducted.
Atherosclerotic cardiovascular disease
Atherosclerosis is a condition characterized by the buildup of plaque in the walls of blood vessels. This plaque can be made of cholesterol and other substances.
Atherosclerosis makes it harder for blood to circulate properly in the body. It can lead to several health complications if left unchecked.
Atherosclerotic cardiovascular disease (ASCVD) is an umbrella term for conditions that can result from atherosclerosis. Heart attacks, strokes, and aneurysms can be examples of atherosclerotic cardiovascular diseases.
Cardiologist at the Texas Heart Institute, Dr. Salim Virani, who was not involved in the study presented at ACC23, explained to Medical News Today that:
“Atherosclerosis is a buildup of fat, cholesterol, and other substances inside the artery walls. That buildup is referred to as plaque. Plaque ultimately causes the arteries to become narrow and eventually restricts blood flow. When the plaque bursts, it can lead to a blood clot — and, in turn, increase the chances for a stroke or heart attack. Atherosclerotic cardiovascular disease includes heart attacks, strokes, stents, bypass surgery or blockage of blood vessels supplying blood to the lower limbs or the brain.”
Understanding apolipoprotein B-100
Because atherosclerotic cardiovascular disease can be deadly, early testing can help people identify and minimize their risk. One area of interest is testing cholesterol levels.
High cholesterol levels, particularly low-density lipoprotein (LDL) cholesterol, can increase the risk for atherosclerosis and atherosclerotic cardiovascular disease.
Testing for cholesterol levels can be part of routine blood work. Still, another test, for ApoB, may help further identify the risk for poor heart health.
“ApoB, short for apolipoprotein B, is the main protein found in LDL particle which carries ‘bad’ cholesterol as well as other particles that carry bad forms of cholesterol. It moves fat throughout the body and helps it get through the walls of arteries, where it can form plaque,” Dr. Virani explained.
“When this happens, it increases [the] risk of heart disease and stroke. Measuring for ApoB is a direct measure of all the particles that could contribute to heart disease within your bloodstream,” he added.
Benefit of testing for ApoB
The study presented at ACC23 examined trends in testing for ApoB and how levels of this protein relate to low-density lipoprotein (LDL) cholesterol levels.
The researchers used data from Intermountain Healthcare electronic medical records, looking at when people were tested for ApoB and LDL cholesterol levels. They examined data collected between 2010 and 2022 from 705 individuals whose average age was 56 years. Of the total number, 41% were female.
First, they found that the amount of testing for ApoB increased throughout this time frame. They also found that ApoB levels may still be elevated, even when LDL cholesterol levels are in a healthy range.
Among their participants, about 46% of them still had elevated ApoB levels, even when LDL cholesterol was less than 70 milligrams per deciliter (mg/dL), a concentration supposed to be in the healthy range.
Study author Dr. Jeffrey L. Anderson explained to MNT:
“Apo-B provides unique information beyond LDL-C [bad cholesterol]. At low LDL-C levels, ApoB may still be elevated. Apo-B [according to] other studies is a better risk predictor than LDL-C, so if elevated, it may indicate small, dense LDL (i.e., cholesterol poor), [and] more aggressive Rx is indicated.”
In other words, when someone has an elevated ApoB level with a normal LDL cholesterol level, they can still be at risk for atherosclerotic cardiovascular disease and should be treated accordingly.
“These ‘small dense LDL’ particles are still atherogenic,” Dr. Anderson further elaborated. This means that they promote the formation of fat deposits in the arteries.
“The implication is that some patients with LDL [under] 70 — especially those with metabolic syndrome, pre-diabetes, or diabetes — may be undertreated,” said Dr. Anderson. “In them, check ApoB, and if ApoB is still elevated ([over] 60 for example), further intensification of lipid-lowering therapy – e.g. with statins or PCSK9 inhibitors — may be indicated.”
Study limitations and continuing research
The study collected data from a limited number of participants from 24 hospitals and approximately 200 clinics in Utah, Idaho, and Nevada. Further studies analyzing larger datasets would be necessary to confirm the study’s findings.
Nevertheless, the current findings suggest that testing for ApoB may benefit people at risk for cardiovascular disease. This particular test is also becoming more common. Once doctors identify someone with elevated ApoB levels, they can create an appropriate treatment plan.
Dr. Virani explained the common steps after finding out that someone’s ApoB level is elevated:
“When high ApoB levels are detected, the initial first steps for treatment are the same as they would be for detection of high LDL cholesterol levels: dietary changes, such as eating foods low in saturated and trans fats and maintaining a healthy weight through diet and exercise. LDL cholesterol-lowering medications, such as statin therapy, are also often prescribed.”
Overall, the study notes that ApoB testing may be needed as another step to help detect risk for atherosclerotic cardiovascular disease.
Dr. Jayne Morgan, cardiologist, executive director of Health and Community Education at Piedmont Healthcare, and creator of the Stairwell Chronicles, not involved in this research noted to MNT that “[t]he continued presence of these small dense particles, even with LDL levels lowered to goal, supports the use of ApoB measurements to further direct heart health therapy and guidance between a physician and a patient.”
“Treating patients aggressively for both prevention and intervention of heart disease, especially with lower LDL levels, may incorporate ApoB levels as a common practice to further determine patients still at risk of cardiac events because of elevated atherogenic particles,” she added.
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