SCAPIS: Simple Questionnaire Can Identify Silent Atherosclerosis

November 13, 2020

Individuals in the general population with high levels of silent coronary atherosclerosis can be successfully identified with a simple questionnaire that they can complete themselves at home, a new study suggests.  

The Swedish CardioPulmonary BioImage Study (SCAPIS) found that 40% of middle-aged adults without known heart disease had evidence of coronary atherosclerosis on coronary CT angiography (CCTA), and 13% had extensive atherosclerotic disease.

The authors found that the screening questionnaire could identify individuals who had extensive coronary atherosclerosis with a reasonably high predictive value.

Initial results from the study were presented today at the virtual American Heart Association (AHA) Scientific Sessions 2020.

"Our study is looking to see if we can estimate how many people in the general population have significant coronary atherosclerosis and therefore could benefit from preventative treatment," lead author, Göran Bergström, MD, explained to Medscape Medical News.

Dr Goran Bergstöm

Bergström, who is professor and lead physician at Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden, said there are no good data on this as yet. "There are studies of atherosclerosis burden in patients who have had a cardiovascular event, but our study was conducted in a random selection of the middle-aged general population who did not have symptoms of heart disease."

"Our study also suggests that in future we may be able to identify these people with an online questionnaire, and those that reached a certain score could be referred for an imaging test," he added.

SCAPIS included more than 30,000 men and women, age 50 to 64 years, who had no history of cardiovascular events or cardiac intervention. They were asked questions about sex, age, lifestyle, smoking, body measurements, cholesterol medication, and blood pressure to predict their risk for coronary artery disease.

Researchers then used CCTA images to examine patients' arteries for the presence of plaque. More than 25,000 individuals from the original sample were successfully imaged.

Results showed that 40% of the middle-aged population had some coronary atherosclerosis and 5% had severe atherosclerosis, defined as the presence of a stenosis blocking 50% or more of blood flow in one of the coronary arteries.   

A second aim of the study was to use data from the questionnaire to develop a prediction model to identify people with widespread atherosclerosis — those with any type of stenosis in four different segments of their coronary arteries, who made up 13% of the population. 

The questionnaire included data on 120 different variables. Of these variables, around 100 could be assessed by the patients themselves and another 20 measurements could be performed in the clinic, such as blood pressure and cholesterol levels.

The researchers then used artificial intelligence to assess which variables were associated with widespread atherosclerosis. This had an area under the curve (AUC, a measure of the predictive value) of 0.8.  

"An AUC of 1.0 would show a perfect prediction, and a value of 0.5 shows no value. A result of 0.8 shows reasonable predictive potential. This is an encouraging result and suggests this strategy could work," Bergström said. 

"We know silent atherosclerosis is a big problem and causes sudden cardiac events in people who have not shown symptoms," he said.

The goal is to identify these patients before they have an event and offer them preventive treatments. "At present we try and identify patients at high risk of cardiovascular events by using cholesterol and blood pressure measurements and cardiovascular risk scores such as Framingham. But this is not so effective," Bergström explained.

"Using imaging such as CCTA, where you can actually see atherosclerotic plaque, could be a better for prediction, but we can't image everyone. So, we wanted to see whether we could narrow down the population who should receive imaging with a detailed questionnaire, and it looks like we can."

The study found that including clinical measurements such as blood pressure and cholesterol did not add much to the predictive value for identifying people with extensive coronary atherosclerosis, a result that Bergström said was surprising.   

Which Population to Target?

Discussant of the study, Pamela Douglas, MD, professor of research in cardiovascular diseases at Duke University, Durham, North Carolina, congratulated the SCAPIS investigators on creating "a very rich data set for current and future study."

"The SCAPIS study has already yielded novel data on the prevalence of coronary artery disease in the general population, and will address many critical questions over the long term," she said.

But Douglas suggested that individuals with extensive coronary atherosclerosis were not the most appropriate target population to identify.

"The rationale for choosing this cutpoint is unclear as clinical risk/mortality is higher in all nonobstructive coronary artery disease, starting at one-vessel involvement," she noted. "Therefore, effective preventive strategies likely need to start with detection and treatment of patients with even minimal plaque."

Responding to Medscape Medical News, Bergström said this was a valid argument. "We plan to reanalyze our results with different populations as the target — that is something that we can do in the future. But targeting everyone with just one coronary plaque is going to identify a large group — it was 40% of the population in our study. This will be too many people in whom to perform confirmatory CCTA imaging. It would be impractical to try and conduct cardiac imaging on that many people."

Bergström noted that more data are needed on the danger of various levels of coronary atherosclerosis in this population who have not had any symptoms. 

"We don't have this information at present, but we are continuing to follow our population and we will have data on cardiac events in a few years' time. Then we will know which level of atherosclerosis we need to target. It will probably be somewhere in between the extensive levels we used in this first analysis (which occurred in 13% of people) and the 40% of people who showed just one area of plaque."

This study is the first report from SCAPIS, a collaborative project between six Swedish universities with the following vision statement: to "reduce the risk of cardiovascular and respiratory diseases for generations to come."

The SCAPIS project is funded by the Swedish Heart and Lung Foundation. Bergström reports no disclosures. 

American Heart Association (AHA) Scientific Sessions 2020.  Session LBS.02. Presented November 13, 2020.

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