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Effect of apixaban on brain infarction and microbleeds: AVERROES-MRI assessment study
Martin J O'Donnell1, John W Eikelboom2, Salim Yusuf2
1Population Health Research Institute, McMaster University, and Hamilton Health Sciences, Hamilton, ON, Canada; HRB-Clinical Research Facility, NUI Galway, Galway, Ireland.
Background:
Clinical and subclinical (covert) stroke is a cause of cognitive loss and functional impairment. In the AVERROES trial, we performed serial brain magnetic resonance imaging (MRI) scans in a subgroup to explore the effect of apixaban, compared with aspirin, on clinical and covert brain infarction and on microbleeds in patients with atrial fibrillation.
Methods:
We performed brain MRI (T1, T2, fluid-attenuated inversion recovery, and T2* gradient echo sequences) in 1,180 at baseline and in 931 participants at follow-up. Mean interval from baseline to follow-up MRI scans was 1.0 year. The primary outcome was a composite of clinical ischemic stroke and covert embolic pattern infarction (defined as infarction >1.5 cm, cortical-based infarction, or new multiterritory infarction). Secondary outcomes included new MRI-detected brain infarcts and microbleeds and change in white matter hyperintensities.
Results:
Baseline MRI scans revealed brain infarct(s) in 26.2% and microbleed(s) in 10.5%. The rate of the primary outcomes was 2.0% in the apixaban group and 3.3% in the aspirin group (hazard ratio [HR] 0.55; 0.27-1.14) from baseline to follow-up MRI scan (mean duration of follow-up: 1 year). In those who completed baseline and follow-up MRI scans, the rate of new infarction detected on MRI was 2.5% in the apixaban group and 2.2% in the aspirin group (HR 1.09; 0.47-2.52), but new infarcts were smaller in the apixaban group (P = .03). There was no difference in proportion with new microbleeds on follow-up MRI (HR 0.92; 0.53-1.60) between treatment groups.
Conclusions:
Apixaban treatment was associated with a nonsignificant trend toward reduction in the composite of clinical ischemic stroke and covert embolic-pattern infarction and did not increase the number of microbleeds in patients with atrial fibrillation compared with aspirin.
Insights
Apixaban showed a trend in reducing strokes and covert brain infarcts in atrial fibrillation patients. The drug did not increase microbleeds compared to aspirin over one year.
Area of Science:
- Neurology
- Cardiology
- Radiology
Background:
- Clinical and subclinical strokes contribute to cognitive decline and functional impairment.
- Atrial fibrillation increases stroke risk.
- Serial brain MRI assesses treatment effects on cerebrovascular events.
Purpose of the Study:
- To evaluate apixaban versus aspirin in preventing clinical and covert brain infarction.
- To assess the impact of apixaban on microbleeds in atrial fibrillation patients.
- To explore apixaban's effect on brain imaging markers of stroke.
Main Methods:
- 1,180 patients with atrial fibrillation underwent baseline brain MRI; 931 completed follow-up MRI after a mean of 1 year.
- Brain MRI sequences included T1, T2, FLAIR, and T2* gradient echo.
- Primary outcome: composite of clinical ischemic stroke and covert embolic infarction; secondary outcomes: new infarcts, microbleeds, and white matter hyperintensities.
Main Results:
- Apixaban group had a 2.0% rate of primary outcomes versus 3.3% in the aspirin group (HR 0.55; nonsignificant trend).
- New infarcts detected by MRI were similar (2.5% apixaban vs. 2.2% aspirin), but smaller in the apixaban group (P = .03).
- No significant difference in new microbleeds between apixaban and aspirin groups (HR 0.92).
Conclusions:
- Apixaban demonstrated a trend toward reducing clinical ischemic stroke and covert embolic-pattern infarction.
- Apixaban did not increase the incidence of microbleeds compared to aspirin.
- Apixaban may offer benefits in reducing stroke burden in atrial fibrillation patients, with imaging support for smaller infarcts.
