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Aspirin does not cut risk in non-obstructive coronary artery disease – Canadian study

Aspirin therapy, as opposed to statin use, for non-obstructive coronary artery (CAD) disease, does not reduce major cardiovascular events, according to a study published in Radiology: Cardiothoracic Imaging.

Coronary artery disease is the most common type of heart disease, affecting roughly 6.7% of American adults, according to the US Centers for Disease Control and Prevention (CDC).

The disease occurs when there is a build-up of plaque in the arteries that supply blood to the heart, and increases the risk of major adverse cardiovascular events, including heart attack and death.

Non-obstructive CAD occurs when there is less than 50% stenosis, or narrowing, of the coronary arteries due to this plaque build-up. Coronary CT angiography (CCTA) is often recommended as a first-line test to detect plaque.

Statins are commonly prescribed for non-obstructive CAD. The medication reduces the production of low-density lipoprotein (LDL) cholesterol and draws cholesterol out of plaque, stabilising the plaque and reducing the risk of it rupturing.

Aspirin is also commonly recommended. However, not much research has been done to determine whether it is effective at reducing major cardiovascular events in patients with non-obstructive coronary artery disease.

“While observational in nature, our data call into question the value of initiating aspirin therapy after the diagnosis of non-obstructive coronary artery disease on a coronary CT angiography,” said study author Dr Jonathan Leipsic, professor and head of the Department of Radiology at the University of British Columbia in Vancouver, Canada.

For the study, researchers used data from the CONFIRM (COronary CT Angiography EvaluatioN For Clinical Outcomes: An InteRnational Multicenter) registry, a large, multinational database of patients who have undergone CCTA. A total of 6,386 patients (mean age 56.0 years, 52% men) who had either no detectable coronary plaque or non-obstructive CAD, were selected. Those with obstructive coronary artery disease that had 50% or greater stenosis were excluded. The mean follow-up period for selected patients was 5.7 years.

A total of 3,571 (56%) of the patients included in the study had no plaque and 2,815 (44%) had non-obstructive CAD. Non-obstructive CAD was associated with a 10.6% risk of all-cause mortality compared with 4.8% in patients without plaque.

Baseline aspirin and statin use were documented for both groups. In individuals with non-obstructive CAD, aspirin therapy was not associated with a reduction in major adverse cardiovascular events. Alternatively, statin use was associated with a significant reduction in cardiovascular events, including heart attack and death.

“Our findings build on prior analyses from the CONFIRM registry at 2.3- year follow-up, which called into question the use of aspirin in the setting of CCTA diagnosed atherosclerosis,” Leipsic said.

Neither aspirin nor statin therapy improved clinical outcomes for patients with no detectable plaque. Aspirin therapy may still be beneficial in cases of high-risk plaque or high plaque burden, Leipsic said.

“Ultimately, further research is required to determine whether, and at what threshold, clinicians should consider prescribing aspirin for patients presenting with non-obstructive coronary artery disease on coronary CT angiography,” he said.

Study details

Aspirin and Statin Therapy for Non-obstructive Coronary Artery Disease: Five-year Outcomes from the CONFIRM Registry

Praveen Indraratna, Christopher Naoum, Sagit Ben Zekry, Heidi Gransar, Philipp Blanke, Stephanie Sellers, Stephan Achenbach, Mouaz Al-Mallah, Daniele Andreini, Daniel Berman, Matthew Budoff, Filippo Cademartiri, Tracy Callister, Hyuk-Jae Chang, Kavitha Chinnaiyan, Benjamin J. W. Chow, Ricardo Cury, Augustin DeLago, Gudrun Feuchtner, Martin Hadamitzky, Joerg Hausleiter, Philipp Kaufmann, Yong‐Jin Kim, Erica Maffei, Hugo Marques, Pedro de Araújo Gonçalves, Gianluca Pontone, Gilbert Raff, Ronen Rubinshtein, Todd Villines, Fay Lin, Leslee Shaw, Jagat Narula, Jeroen Bax, Jonathon Leipsic.

Published in Radiology: Cardiothoracic Imaging on 28 April 2022

Abstract

Purpose
In this cohort study, 5-year data from the Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter Registry (ie, CONFIRM) were examined to identify associations of baseline aspirin and statin use with mortality, major adverse cardiovascular events (MACE), and myocardial infarction (MI) in individuals without substantial (≥50%) stenosis.

Materials and Methods
In this prospective cohort study, all participants in the registry underwent coronary CT angiography and were classified as having no detectable coronary plaque or having non-obstructive coronary artery disease (CAD) (1%–49% stenosis). Participants with obstructive (≥50%) stenosis were excluded from analysis. The study commenced in June 2003 and was completed in March 2016. All unadjusted and risk-adjusted analyses utilised the Cox proportional hazard model with hospital sites modelled using shared frailty.

Results
A total of 6386 participants with no detectable plaque or with non-obstructive CAD were included (mean age, 56.0 years ± 13.3 [SD], 52% men). The mean follow-up period was 5.66 years ± 1.10. Non-obstructive CAD (n = 2815, 44% of all participants included in the study) was associated with a greater risk of all-cause mortality (10.6% [298 of 2815] vs 4.8% [170 of 3571], P < .001) compared to those without CAD (n = 3571, 56%). Baseline aspirin and statin use was documented for 1415 and 1429 participants, respectively, with non-obstructive CAD, and for 1560 and 1565 participants without detectable plaque, respectively. In individuals with non-obstructive CAD, baseline aspirin use was not associated with a reduction in MACE (10.9% [102 of 936] vs 14.7% [52 of 355], P = .06), all-cause mortality (9.6% [95 of 991] vs 10.9% [46 of 424], P = .468), or MI (4.4% [41 of 936] vs 6.2% [22 of 355], P = .18). On multivariate risk-adjusted analysis, baseline statin use was associated with a lower rate of MACE (hazard ratio, 0.59; 95% CI: 0.40, 0.87; P = .007). Neither therapy improved clinical outcomes for participants with no detectable plaque.

Conclusion
In participants with non-obstructive CAD, baseline use of statins, but not of aspirin, was associated with improved clinical outcomes. Neither therapy was associated with benefit in participants without plaque.

 

Radiology: Cardiothoracic Imaging article – Aspirin and Statin Therapy for Nonobstructive Coronary Artery Disease: Five-year Outcomes from the CONFIRM Registry (Open access)

 

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