How high cholesterol combined with high blood pressure increases risk

How High Cholesterol Combined With High Blood Pressure Increases Risk

ISLAMABAD, (Online) - In a new study, researchers say people with hypertension and high cholesterol could have an 18 to 20% higher risk of cardiovascular disease.

This increase, they reported, was not seen in people only with hypertension.

Their findings were published today in Hypertension, an American Heart Association journal.

Researchers used health data from the Multi-Ethnic Study of Atherosclerosis (MESA), an ongoing community-based study.

The new study involved 6,674 MESA participants with documented cardiovascular disease who had lipoprotein levels and blood pressure assessed.

The researchers completed follow-ups in 2001, 2003, 2004, 2006, 2010, and 2017. Telephone interviews every 9 to 12 months provided information on new diagnoses, procedures, hospitalizations, and deaths. The scientists tracked cardiovascular events such as heart attack, cardiac arrest, and stroke.

In particular, the researchers looked at lipoproteins (Lp(a)), which are made up of protein and carry fat and cholesterol through the blood.

They are considered a type of “bad” cholesterol. Lp(a) might deposit and build up on the walls of blood vessels, increasing a person’s risk of heart attack or stroke.

What researchers uncovered about cardiovascular health risk

The researchers divided the participants into four groups based on their lipoprotein and blood pressure at the start of the study:

• Group 1 (2,837 people): lipoprotein(a) levels less than 50 mg/dL and no hypertension.

• Group 2 (615 people): lipoprotein(a) levels greater than or equal to 50mg/dL and no hypertension

• Group 3 (2,502 people): lipoprotein(a) levels less than 50mg/dL and hypertension

• Group 4 (720 people): lipoprotein(a) levels = 50mg/dL and hypertension

The researchers reported that there was a high amount of cardiovascular disease due to high blood pressure.

Still, people with hypertension in addition to elevated lipoprotein were at an even higher risk of developing cardiovascular disease.

“We found that among people with hypertension who have never experienced a stroke or heart attack before, lipoprotein(a) seems to increase the risk of cardiovascular disease and a major cardiovascular event like a heart attack or stroke,” the researchers wrote.

“I find the results surprising. The expected finding would be that an elevation in lipoprotein(a) level would lead to a greater risk for cardiovascular events regardless of hypertensive status,” said Dr. Rigved Tadwalkar, a cardiologist at Providence Saint John’s Health Center in California.

“However, this study shows that a significant association only holds for those with hypertension. This should prompt us as a community to better study the mechanisms behind how lipoprotein(a) and hypertension interact,” Tadwalkar told Healthline.

For the study, the scientists defined high blood pressure as more than 140/90 or the use of blood pressure medication. However, in 2017 the American Heart Association revised its definition of high blood pressure as being 130/80 or higher, meaning a more significant percentage of the participants could now be diagnosed with hypertension.

What experts think of cardiovascular risk study

“Hypertension has long been known to increase the risk of cardiovascular disease, and this study reaffirms the strong correlation between hypertension and heart disease,” said Dr. Jim Liu, a cardiologist at The Ohio State University Wexner Medical Center. “Meanwhile, lipoprotein(a) has emerged as another tool to define cardiac risk better and elevated levels are thought to be an independent risk factor for developing a cardiac disease.”

“This is reflected in the study where patients with hypertension and elevated lipoprotein(a) were more likely to develop cardiovascular disease than hypertension alone,” Liu told Healthline. “In some patients, with certain risks for cardiovascular disease that traditional risk factors might not fully capture, it might be helpful to check lipoproteins.”

Not everyone agrees that only Lp(a) with hypertension increases the risk of cardiovascular disease.

“We know that as Lp(a) increases further, cardiovascular disease risk increases as well,” said Dr. William L. Blau, a cardiologist at NYU Langone Ambulatory Care Lake Success and NYU Langone’s Center for Prevention of Cardiovascular Disease.

“To conclude that all patients with Lp(a) over 50mg/dl without hypertension are not at increased risk may not be accurate,” Blau told Healthline. “We know from prior studies that the risk of cardiovascular events increases with increasing Lp(a) levels independent of hypertension. This trial might not have included enough patients to break down risks for rising levels of lipoproteins statistically.”

Looking to the future

Lipoprotein screening is not routinely requested by cardiologists in the United States and around the world, according to a report published in 2019. According to the authors, one reason is that clinicians are often unaware of therapeutic therapies for use when high lipoprotein levels are high. This isn’t necessarily true and people could benefit from screening, they said.

Because Lp(a) levels remain relatively consistent throughout a person’s life, regular screening isn’t required, but identifying people with high Lp(a) levels is the first step, they added.

“Traditional anti-lipid medication such as statins have minimal effect on LP(a),” said Dr. Hoang Nguyen, an interventional cardiologist at MemorialCare Heart & Vascular Institute at Orange Coast Medical Center in California.

“But recently, there have been exciting results on PCSK9 inhibitors. PCSK9 is a type of injectable cholesterol-lowering drug. They prevent the breakdown of LDL receptors on the surface of liver cells. This, in turn, allows for more active LDL receptors and, thus, lower cholesterol levels. This can be an expensive medication and requires close consultation with your cardiologist.” Nguyen told Healthline.

Since lipoprotein(a) is an emerging risk factor, some doctors do regularly request Lp(a) screenings, not necessarily for treatment purposes but to better understand their patient’s cardiovascular disease risk level.

“Currently, I run a one-time lipoprotein(a) level in most of my patients,” Tadwalkar said. “The results are informative in further establishing the degree of cardiovascular risk. As we learn more, we can better apply knowledge about what a particular individual’s lipoprotein(a) level means for them as they progress through life.”

How to lower lipoprotein levels

Lipoprotein levels are primarily genetic.

“There is little we can do, at least in day-to-day life, to influence levels,” Tadwalkar said. “While some medications can decrease levels, they have not yet been shown to reduce cardiovascular event rates, likely due to the inability to sufficiently lower levels.”

As Nguyen pointed out, PCSK9 inhibitors might help. These drugs, including alirocumab (Praluent) and evolocumab (Repatha), work to lower lipid levels and reduce cardiovascular events but have fewer side effects than statins.

There have been phase 2 clinical trials with two classes of medications to lower Lp(a), including:

• Pelacarsen, an antisense oligonucleotide. The phase 3 Lp(a) HORIZON cardiovascular outcomes study enrollment is complete with results expected in 2025.

• Olpasiran, an a small interfering RNA. In a phase 2 study, the medication reduced Lpa levels by more than 95% in people with established ASCVD. A phase 3 trial is now enrolling participants.

“People with elevated Lp(a) are the most likely to benefit from more aggressive LDL lowering, including statin therapy, ezetimibe, or PCSK9 inhibitors,” Blau said.