Incidence of cardioembolic stroke including paradoxical brain embolism in patients with acute ischemic stroke before and after the Great East Japan Earthquake

Background: The incidence of heart disease or deep vein thrombosis (DVT) reportedly increased after the Great East Japan Earthquake. We hypothesized that the incidence of cardioembolic stroke (CES) including paradoxical brain embolism (PBE) among patients with acute stroke would increase after the earthquake due to cessation of antithrombotic therapy or the increase in heart disease and DVT associated with the evacuation. The aim of this study is to evaluate the changes in the prevalence of DVT and the incidence of CES including PBE in acute ischemic stroke before and after the earthquake.

Methods: We retrospectively studied 1,044 consecutive ischemic stroke patients (73.1 ± 12.5 years old, male 61.5%) who were admitted to a comprehensive stroke center (from January 2010 through March 2012) located in the earthquake disaster area within 7 days after stroke onset. The prevalence of DVT and the incidence of CES including PBE were compared before and after the earthquake of 11 March 2011.

Results: The median of the initial National Institutes of Health Stroke Scale (NIHSS) scores was 4 (interquartile range: 1-8). Two hundred and eighty-two patients (27.0% of those surveyed) were diagnosed with CES. After adjustment for sex, age, NIHSS score, and patient's residential address, the proportion of CES patients was significantly increased after the earthquake (odds ratio, OR 1.61, 95% confidence interval, 95% CI: 1.20-2.17). Eighty-nine patients (8.5% of those surveyed) had DVT. Compared with 2010 findings, the prevalence of DVT was significantly increased in the fourth quarter of 2011 and the first quarter of 2012 (OR 1.85, 95% CI: 1.05-3.24). Nineteen (1.8% of those surveyed) were diagnosed with PBE. The proportion of PBE patients was also significantly increased in the second half of 2011 (OR 3.69, 95% CI: 1.28-12.1).

Conclusions: The incidence of CES was significantly increased after the earthquake, compared with the period before the earthquake. We encountered more PBE in the period from 3 to 9 months after the earthquake and found more DVT in the acute ischemic stroke patients in the period from 6 through 12 months after the earthquake. In these types of disasters, we have to ensure the distribution of drugs, including antithrombotics, and support the prevention of DVT in the refugees.