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Covert Brain Infarction as a Risk Factor for Stroke Recurrence in Patients With Atrial Fibrillation
Do Yeon Kim1, Seok-Gil Han1, Han-Gil Jeong1,2
1Department of Neurology and Cerebrovascular Center (D.Y.K., S.-G.H., H.-G.J., K.-J.L., B.J.K., M.-K.H., H.-J.B.), Seoul National University College of Medicine, Seongnam, Republic of Korea.
Insights
Covert brain infarction (CBI) increases the risk of recurrent ischemic stroke in patients with atrial fibrillation (AF). Identifying CBI, especially embolic-appearing patterns, is crucial for stroke risk assessment in AF patients.
Area of Science:
- Neurology
- Cardiology
- Stroke Medicine
Background:
- Covert brain infarction (CBI) is often detected during acute ischemic stroke work-ups.
- Atrial fibrillation (AF) is a significant risk factor for ischemic stroke.
Purpose of the Study:
- To evaluate covert brain infarction (CBI) as a predictor of stroke recurrence in patients with atrial fibrillation (AF).
Main Methods:
- Prospective cohort study of 1383 AF patients hospitalized for first-ever ischemic stroke.
- Categorization of CBI into embolic-appearing (EA) and non-EA patterns.
- Comparison of 1-year recurrent ischemic stroke and all-cause mortality rates between CBI (+) and CBI (-) groups using competing risk models.
Main Results:
- 41.8% of AF patients had CBI; 61.8% of these had EA pattern CBI.
- CBI significantly increased the 1-year risk of recurrent ischemic stroke (aHR, 2.91).
- EA pattern CBI and both EA/non-EA CBI patterns were associated with higher recurrent stroke risk, unlike non-EA pattern CBI alone.
Conclusions:
- AF patients with CBI face a higher risk of recurrent stroke.
- CBI, particularly EA pattern, should be considered in stroke risk stratification for AF patients.
Background:
We aimed to evaluate covert brain infarction (CBI), frequently encountered during the diagnostic work-up of acute ischemic stroke, as a risk factor for stroke recurrence in patients with atrial fibrillation (AF).
Methods:
For this prospective cohort study, from patients with acute ischemic stroke hospitalized at 14 centers between 2017 and 2019, we enrolled AF patients without history of stroke or transient ischemic attack and divided them into the CBI (+) and CBI (-) groups. The 2 groups were compared regarding the 1-year cumulative incidence of recurrent ischemic stroke and all-cause mortality using the Fine and Gray subdistribution hazard model with nonstroke death as a competing risk and the Cox frailty model, respectively. Each CBI lesion was also categorized into either embolic-appearing (EA) or non-EA pattern CBI. Adjusted hazard ratios and 95% CIs of any CBI, EA pattern CBI only, non-EA pattern CBI only, and both CBIs were estimated.
Results:
Among 1383 first-ever stroke patients with AF, 578 patients (41.8%) had CBI. Of these 578 with CBI, EA pattern CBI only, non-EA pattern CBI only, and both CBIs were 61.8% (n=357), 21.8% (n=126), and 16.4% (n=95), respectively. The estimated 1-year cumulative incidence of recurrent ischemic stroke was 5.2% and 1.9% in the CBI (+) and CBI (-) groups, respectively (P=0.001 by Gray test). CBI increased the risk of recurrent ischemic stroke (adjusted hazard ratio [95% CI], 2.91 [1.44-5.88]) but did not the risk of all-cause mortality (1.32 [0.97-1.80]). The EA pattern CBI only and both CBIs elevated the risk of recurrent ischemic stroke (2.76 [1.32-5.77] and 5.39 [2.25-12.91], respectively), while the non-EA pattern only did not (1.44 [0.40-5.16]).
Conclusions:
Our study suggests that AF patients with CBI might have increased risk of recurrent stroke. CBI could be considered when estimating the stroke risk in patients with AF.
