Calcium scans of the coronary arteries, as shown here, are used to measure the amount of calcium lining the arteries of the heart and to assess the risk of a heart attack or stroke. Photo credit: UT Southwestern Medical Center

An X-ray test, commonly used to assess hardening of the arteries, could help doctors decide whether the benefits of taking aspirin to prevent a first-time heart attack or stroke outweigh the risk of bleeding, research from UT Southwestern suggests.

The results, published online today in JAMA Cardiology, could provide clinicians and patients with more specific guidance on making this important decision.

Because of its anticoagulant properties, aspirin is often prescribed as a preventive measure for patients who have already had cardiovascular events such as heart attack or ischemic stroke. However, the role of aspirin in primary prevention – averting the first heart attacks and strokes – is unclear, explains study director MD, professor of internal medicine and director of the

After decades of co-prescribing aspirin for primary prevention, recent results from the American Heart Association (AHA) and the American College of Cardiology (ACC) recommend more selective use for those at highest risk for cardiac events due to the increased risk of bleeding.

“We used to say for aspirin, generally yes, occasionally no,” says Khera. “With these new guidelines we have turned that on its head and say we shouldn’t use aspirin for most people in primary prevention.”

However, it is unclear how one can choose which patients could benefit most from aspirin therapy, taking into account the risk of bleeding. “We need tools to find the sweet spot where aspirin is most beneficial and offset the risks involved,” he says.

In the study, Khera and his colleagues looked at a diagnostic test to see if it could help doctors make this important decision. CAC scanning, a CT scan that measures the amount of calcium lining the arteries in the heart, is usually done to check for hardening of the arteries and the risk of a heart attack or stroke.

The researchers collected data from the Dallas Heart Study, an ongoing study that tracks cardiovascular disease development in more than 6,000 adults in Dallas County. Initially, attendees were invited to three visits to collect health and demographic information, laboratory samples, and various imaging tests, including CAC scanning. These volunteers were then followed up for an average of 12 years to follow up those who had a heart attack, died of heart disease, or had a non-fatal or fatal stroke – medical problems collectively known as atherosclerotic cardiovascular disease – and / or who have had a bleeding event that resulted in hospitalization or death.

The researchers used data from 2,191 participants, with a mean age of 44, who had access to CAC scans and follow-up information. About 57 percent were female and 47 percent were black.

Overall, about half of the participants had a CAC score of 0, which suggests that little to no calcium accumulated in their arteries. About 7 percent had a CAC value greater than 100, which indicates a high level of calcium formation. The rest had values ​​in the middle (1-99).

When Khera and his colleagues examined the incidence of atherosclerotic cardiovascular disease (ASCVD) and bleeding in the study group, they found that both events increased gradually with increasing CAC values. However, when they used statistical models to determine how many of the ASCVD events could possibly have been prevented by the use of aspirin, based on values ​​obtained from a recent meta-analysis that informed the AHA and ACC guidelines they found that the benefits of aspirin only outweighed the risks for those with CAC scores above 100. For this group, the risk of ASCVD was about 15-fold and the risk of bleeding was about three-fold for those with a CAC of 0.

However, this effect only applied to those whose inherent risk of bleeding was already low, says Khera, which means that in practice, as noted in the guidelines, someone has previously had significant bleeding episodes, risk factors for bleeding, or was taking medication to increase bleeding, They should not take aspirin for primary prevention regardless of their CAC value.

Together, Khera said, the results reinforce new guidelines that suggest that aspirin for primary prevention is only suitable for select patients and that CAC scanning can help doctors and patients make that decision.

“Aspirin use is not a unitary therapy,” says Khera, who holds the Dallas Heart Ball Chair for High Blood Pressure and Heart Disease. “CAC scanning can be a valuable tool in adapting care so that more patients can avoid their first heart attack or stroke.”

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More information:
Ezimamaka Ajufo et al. Value of calcium scanning of the coronary artery in association with the net utility of aspirin in primary prevention of atherosclerotic cardiovascular disease, JAMA Cardiology (2020). DOI: 10.1001 / jamacardio.2020.4939 Provided by UT Southwestern Medical Center

Quote: Aspirin is best for those with high coronary calcium levels and low risk of bleeding (2020, October 30th), who will be registered on October 30th, 2020 at https://medicalxpress.com/news/2020-10-aspirin-high-coronary-calcium .html

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