High prevalence of unrecognized cerebral infarcts in first-ever stroke patients with cardioembolic sources

Background: With magnetic resonance imaging (MRI) analysis, we investigated the prevalence, clinical significance, and factors related to the presence of unrecognized cerebral infarcts in patients with first-ever ischaemic stroke. Methods: We consecutively included patients who were admitted with first-ever stroke. Unrecognized cerebral infarct was defined as an ischaemic infarction or primary intracerebral hemorrhage on MRI irrelevant to the index stroke, without acute lesions on diffusion-weighted image. Results: Of the total 203 patients, 78 (39.4%) patients were observed as having unrecognized cerebral infarct. Patients with high-risk cardioembolic sources (e.g., atrial fibrillation) more frequently had unrecognized stroke than those without (P = 0.008, 21/36 [58.3%] vs. 57/167 [34.1%]). On univariate analysis, male sex (P = 0.027) and cardioembolic source (P = 0.008) were associated with the presence of unrecognized cerebral infarcts. After adjustment for gender, age and risk factors, the presence of cardioembolic sources independently increased the risk of unrecognized cerebral infarct (P = 0.002, odds ratio 3.56, 95% confidence interval 1.58-8.02). Regarding clinical outcome at 3 months, the presence of unrecognized cerebral infarct was not associated with the poor clinical outcome. Conclusion: In our study, the presence of cardioembolic sources was an independent risk factor for the unrecognized cerebral infarct in patients with first-ever stroke.