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Heart Disease: CT Scans May Be Best For Predicting Risk During Middle Age
On average, someone in the United States dies of cardiovascular disease (CVD) every 34 seconds.
Yet the World Health Organization (WHO) estimates that over 75% of early cardiovascular disease cases are preventable.
To minimize the risk of heart disease, it's important for doctors to assess an individual's risk factors, particularly for coronary heart disease (CHD). This is done using risk models that take into account various factors, including age, sex, blood pressure, cholesterol levels, diabetes status, and smoking status.
Earlier this year, the 20-year results of the Heinz Nixdorf Recall (HNR) study showed that individual risk prediction is improved by the addition of coronary artery calcification to the traditional risk score. However, no studies to date have directly compared coronary artery calcium and polygenic risk scores in the same cohort.
To address this knowledge gap, researchers at Northwestern University Feinberg School of Medicine analyzed data on both risk scores from two cohorts of middle-aged to older adults from the United States and the Netherlands.
They compared the change in coronary heart disease risk prediction when a coronary artery calcium score, a polygenic risk score, or both were added to a traditional risk factor-based model.
The findings were published in JAMA on May 23.
Risk models help doctors to determine whether treatments like lipid-lowering therapy or lowering blood pressure are necessary based on the level of cardiovascular disease risk.
But these conventional risk scores do not always provide accurate estimates and new risk markers for coronary heart disease are being explored.
One such marker is coronary artery calcium (calcium plaque in the walls of coronary arteries), which is a strong predictor of future coronary heart disease and can be detected using computed tomography (CT) scans.
In addition, research has shown that genetics play an important role in the development of coronary heart disease.
Another approach for determining a person's risk of developing the condition is the use of polygenic risk scores, which calculate coronary heart disease risk based on a person's genes.
The present study included data from two observational population-based studies involving White individuals ages 45 to 79, who did not have coronary heart disease at baseline: the Multi-Ethnic Study of Atherosclerosis (MESA) and the Rotterdam Study (RS), conducted in the U.S. And the Netherlands respectively.
Only individuals of European ancestry were included in the Northwestern study due to previous evidence suggesting that the polygenic risk score performs better in European populations.
Furthermore, participants with missing data or those taking lipid-lowering therapy at the beginning of the study were excluded, resulting in a final analysis population of 1,991 MESA participants and 1,217 RS participants.
Lead researcher Dr. Sadiya S. Khan, an assistant professor of medicine and preventive medicine at Northwestern University, and her team assessed coronary heart disease risk based on traditional risk factors.
They used the 2013 ACC/AHA Pooled Cohort Equations (PCEs) to calculate the predicted 10-year risk of atherosclerotic cardiovascular disease for each participant. This risk prediction model considered factors such as age, sex, smoking status, blood pressure, cholesterol levels, diabetes status, and hypertension treatment.
Then, they evaluated coronary heart disease risk using the coronary artery calcium score and the polygenic risk score for each participant.
In both the MESA and RS studies, the occurrence of coronary heart disease events, including myocardial infarction, angina, resuscitated cardiac arrest, and death from coronary heart disease, was monitored through in-person examinations approximately every 18 months and annual telephone follow-up conversations.
Finally, Dr. Khan and coworkers conducted statistical analyses to examine the association between coronary heart disease risk predictors (PCEs, coronary artery calcium score, and polygenic risk score) and the actual occurrence of coronary heart disease.
The median age was 61 years in MESA and 67 years in RS.
The results showed that both the coronary artery calcium score and the polygenic risk score were significantly associated with a 10-year risk of coronary heart disease: 2.60 times higher risk per standard deviation (SD) increase for coronary artery calcium score, and 1.43 times higher risk per SD increase for polygenic risk score.
The researchers used a statistical measure called the C statistic to assess the ability of the coronary artery calcium score and the polygenic risk score to predict the risk of coronary heart disease. The C statistic for the coronary artery calcium score was 0.76, indicating moderate predictive ability, and for the polygenic risk score, it was 0.69, indicating slightly lower predictive ability.
When the coronary artery calcium score was added to the traditional risk factors, there was a significant improvement in risk prediction (an increase in the C statistic of 0.09).
However, when the polygenic risk score was added, the improvement was smaller (an increase in the C statistic of 0.02). When both scores were added, there was a larger improvement (an increase in the C statistic of 0.10).
The researchers obtained similar results when they repeated the analyses with age-stratified subgroups, and with longer-term follow-up data from the MESA study (median 16.0 years).
Dr. Joseph F. Polak, MPH, professor of radiology at Tufts University School of Medicine, who is involved in the MESA study, said he was not surprised by these results. He explained to Medical News Today:
"This is likely an example of what we commonly refer to as vascular age. Basically, a person is as old as their arteries. In this case, a direct measurement of the 'age' of the artery trumps genetics."
Dr. Raimund Erbel, professor emeritus of medicine and cardiology at Essen University Hospital and the University of Duisburg-Essen, and principal investigator of the Heinz Nixdorf Recall Study, also agreed with the conclusions of this study and described CT as "a wonderful tool for individual cardiovascular[r] risk prediction" in his comments to MNT.
When asked to comment about the implications of these findings, Dr. Erica Spatz, associate professor of cardiology and epidemiology at Yale University, told MNT that "this study validates our current approach to cardiovascular risk assessment, whereby a calcium score can meaningfully up- or down-grade a person's cardiovascular risk, especially when that risk is greater than 7.5%."
Dr. Spatz explained that "calcium scores can enhance shared decision-making discussions about how aggressive to be with prevention, including decisions about statins and other lipid-lowering agents, LDL targets, and overall lifestyle goals."
"Polygenic risk scores are the new kid on the block for risk stratification; they impart additional information about a person's cardiovascular risk, but we are still trying to figure out their place in clinical practice," Dr. Spatz added.
Dr. Karol E. Watson, PhD, professor of medicine and cardiology at the David Geffen School of Medicine at the University of California Los Angeles, warned that the findings are "not definitive" since the study is limited to "a specific population" and "specific polygenic risk scores."
"What this study says is that in white participants enrolled in 2 observational studies, identifying coronary calcium predicted future cardiac events better than our currently available polygenic risk scores. This doesn't mean that CAC [coronary artery calcium] predicts better than genetics. It only mean[s] that CAC predicted incident events better than the specific polygenic risk scores they used in these specific white populations."
– Dr. Karol E. Watson, PhD, professor of medicine and cardiology, UCLA
Prof. Dr. Michiel L. Bots, PhD, professor of epidemiology of cardiovascular disease at UMC Utrecht, remarked that evidence of the usefulness of adding the coronary artery calcium score to traditional risk markers "has been available for certainly a decade."
However, Dr. Bots noted there will always be some low risk individuals who may experience a cardiovascular event, while some higher-risk individuals, such as those with high levels of coronary calcium, may not.
Managing Cardiovascular Disease Risk Factors May Help Preserve Physical Function As We Age
Managing cardiovascular disease (CVD) risk factors may play a role in preserving physical function during the aging process, according to new research published today in The Journals of Gerontology: Series A.
"Approximately 10% of older adults have muscle weakness and diminished physical function that leads to adverse health outcomes and physical disability," said lead author Dr. Shivani Sahni. "Since loss of physical function contributes to reduced mobility, disability, institutionalization, and mortality, management of CVD risk factors can help preserve physical function with age," she said.
This study showed that vascular measures are associated with grip strength in cross-sectional analyses and change in gait speed (a measure of physical function) in longitudinal analyses.
"This is one of the first community-based studies to comprehensively examine relations of aortic stiffness and vascular function with age-related decline in physical function. Higher aortic stiffness was associated with loss of physical function over ~11 years," said Dr. Sahni, who is an Associate Professor of Medicine at Harvard Medical School and an Associate Scientist at the Hinda and Arthur Marcus Institute for Aging Research at Hebrew SeniorLife. She directs the Nutrition Program at the Marcus Institute.
"Blood flow declines with aging, in part due to arterial stiffening. Consequent dysfunction in blood vessel dynamics may contribute to organ pathology and declines in muscle mass," explains Dr. Sahni. Yet, few studies have specifically assessed the role of vascular function, and changes in functional muscle measures such as mobility and muscle strength.
The current study utilized data from a large cohort of relatively healthy men and women and extends previous investigations by utilizing a longitudinal study design.
The majority of previously published studies have utilized cross-sectional study designs with modest sample sizes. The authors believe that future studies should evaluate whether interventions that target vascular health may reduce age-related declines in physical function. This is important because one third of older adults experience physical limitations contributing to reduced mobility, disability, institutionalization, and mortality. Hence, there is a need for development of novel interventions that target prevention of physical limitations in older adults.
More information: Shivani Sahni et al, Association of Vascular Health Measures and Physical Function: A Prospective Analysis in the Framingham Heart Study, The Journals of Gerontology: Series A (2023). DOI: 10.1093/gerona/glad097
Provided by Hebrew SeniorLife Hinda and Arthur Marcus Institute for Aging Research
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CT Scans May Be Best For Predicting Heart Disease Risk Compared To Genetics
Doctors use different factors to estimate a person's risk for heart attack, stroke, or other cardiovascular problems. This estimate takes into account conventional risk factors such as age, sex, cholesterol levels, blood pressure, diabetic status, and smoking status, among others.
When combined, this information helps doctors decide when to recommend lifestyle changes, lipid-lowering statins, or other medications. Early treatment of underlying factors can reduce the risk of having a cardiovascular problem.
While these conventional factors may provide a good assessment of a person's risk, there is room for improvement. For example, some people may experience a heart attack or other cardiovascular issues even when these factors do not indicate they are at high risk.
To improve risk assessment, scientists have suggested including other methods. One of these is a polygenic risk score, which is based on more than 6 million commonly occurring genetic variants associated with heart disease.
Another method is a CT scan for coronary artery calcium, which is a sign of atherosclerosis, a thickening or hardening of the arteries.
Now, in a new study, published May 23 in JAMA, researchers found that CT scans for coronary artery calcium do a better job than genetic testing at estimating a person's risk of heart disease during mid-life, when added to conventional factors.
"These findings support recommendations to consider CT screening to calculate risk for heart disease in middle-aged patients when their degree of risk is uncertain or in the intermediate range," Dr. Sadiya Khan, a cardiologist and assistant professor of medicine and preventive medicine at Northwestern University Feinberg School of Medicine, said in a news release.
The American College of Cardiology's ASCVD Risk Estimator measures the risk for atherosclerotic cardiovascular disease. Low risk means someone has less than a 5% chance of developing cardiovascular disease due to atherosclerosis in the next 10 years. Above a 7.5% intermediate risk, statins are recommended.
For the study, researchers looked at data from over 3,200 middle-aged and older adults ranging from 45 to 79 years old from two groups, one in the United States and the other in the Netherlands. All participants were of European descent, so the results may not apply to other groups.
The researchers assessed participants' risk of coronary heart disease using conventional risk factors.
The participants also had a CT scan done to determine their coronary artery calcium score and a genetic test to estimate their polygenic risk score.
Researchers followed people for up to 17 years, with regular in-person exams and telephone check-ins.
Based on conventional factors, participants' risk of cardiovascular disease was 6% to 7% on average, researchers found. In contrast, around 8% to 9% of people developed heart disease during the follow-up period.
When researchers considered the coronary artery calcium score alongside conventional factors, however, the risk estimate became greater. In contrast, the genetic score had no impact.
"This suggests that incorporating genetic information through polygenic risk scores … may have limited clinical utility in predicting coronary heart disease risk, compared to traditional risk factors and the coronary artery calcium score," Dr. Elliott J Elias, a cardiologist at Baptist Health Miami Cardiac & Vascular Institute, told Healthline.
Elias, who was not involved in the new study, pointed out that more research is needed to determine how well coronary artery calcium scores predict longer-term outcomes, as well as the cost-effectiveness and feasibility of this test in different healthcare settings.
The authors of the new study write that more research is also needed to show whether improving heart disease risk assessments translate to better outcomes for individuals.
For example, when doctors communicate this greater risk to their patients, are they more likely to take steps to lower that risk, such as by changing their diet or taking statins or blood pressure medication?
A 2022 study by Australian researchers sought to answer this question.
While the results of the study found that coronary artery calcium score is useful for predicting heart disease risk, the authors said there may still be a use for genetic scores.
"It is possible that the polygenic risk score and coronary artery calcium score may each be clinically relevant at different life stages," they wrote.
Participants in the study were middle-aged or older, so they were more likely to have some amount of calcium in the arteries around the heart, which represents early signs of heart disease.
Younger adults, though, may not have developed coronary artery calcium, the researchers said. In this case, a genetic score may be able to identify people who have a higher genetic risk of developing heart disease later on.
Dr. Mary Greene, a cardiologist with Manhattan Cardiology in New York City, said a coronary artery calcium score test is already recommended for people with a borderline to intermediate risk of coronary artery disease. This test helps refine the risk assessment.
This recommendation is included in the 2019 American College of Cardiology and American Heart Association guidelines on the prevention of cardiovascular disease.
"All persons over 40 years old with at least one cardiovascular risk factor should be getting a coronary artery calcium score," Green told Healthline.
Risk factors may include:
Green added that obtaining coronary artery calcium scores in lower risk groups who may have previously been overlooked will provide the "opportunity to aggressively modify their risk factors before overt clinical symptoms of heart disease occur."
"Additionally, going to the cardiologist to be risk-stratified for heart disease can enable one to identify all possible risk factors and manage those risk factors before the overt clinical disease is diagnosed," she said.
People who are at higher risk of heart disease — including those who have a higher genetic risk — can take steps to lower that risk.
"Taking proactive steps such as quitting smoking, adopting a healthy diet, engaging in regular physical activity, and maintaining a healthy weight are crucial for lowering the risk of heart disease," Elias said.
If your doctor diagnoses you with a health condition such as high blood pressure, type 2 diabetes and high cholesterol, managing these with lifestyle changes and medications can help lower the risk of heart disease.
Elias emphasized that reducing your risk of heart disease is not something you do alone but in partnership with your healthcare team.
"Encouraging patients to actively participate in their own care by implementing lifestyle modifications and adhering to prescribed treatments is essential for enhancing overall cardiovascular health," he said.
Medical professionals assess people for heart disease by taking conventional factors like age, sex, and blood pressure levels into account.
While these conventional factors are useful, they are not the only factors for determining heart disease risk. Other methods like genetic testing and CT scans may help provide a more thorough picture of a person's cardiovascular health.
A new study compared the use of CT scans and genetic testing alongside conventional factors and found that CT scans were more effective at determining heart disease risk, but genetic scores may still be useful.
Healthy lifestyle choices, weight management, regular physical activity, and avoiding smoking may help reduce your risk of developing cardiovascular problems.
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