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 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.”
Dr. Pamela Douglas
“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.