Paradoxical brain embolism may not be uncommon-prospective study in acute ischemic stroke.
BACKGROUND
Proving that right-to-left shunt (RLS) represents the precise causative mechanism in ischemic stroke patients with RLS is difficult. The aim of this study was to examine the frequency and clarify the clinical characteristics of paradoxical brain embolism (PBE).


METHODS
We prospectively enrolled consecutive acute ischemic stroke patients, who underwent transcranial Doppler and/or transesophageal echocardiography. For patients with RLS, diagnostic criteria for PBE were established as follows: 1) brain images suggesting embolic strokes; 2) presence of deep venous thrombus or pulmonary embolism; and 3) absence of any embolic sources. Patients were divided into 4 groups: patients meeting all 3 criteria (Definite); fulfilling 2 criteria (Probable); fulfilling 1 or 0 criteria (Possible); and patients without RLS (Non-RLS).


RESULTS
A total of 240 subjects were analyzed for this study. The Definite group comprised 5% of patients, and displayed significantly more females (p = 0.038), and infarcts involving both anterior and posterior circulations (p < 0.001). Patients having neither hypertension nor diabetes mellitus also predominantly belonged to the Definite group (p < 0.001).


CONCLUSIONS
Clinical characteristics of PBE are a female preponderance, infarcts affecting both anterior and posterior circulations, and an absence of risk factors.
Ueno
Yuji
Y
Stroke center, Dept. of Stroke Medicine, Kawasaki Medical School, 577 Matsushima, Kurashiki-city, Okayama, 701-0192, Japan. yuji-u@med.juntendo.ac.jp
Iguchi
Yasuyuki
Y
Inoue
Takeshi
T
Shibazaki
Kensaku
K
Urabe
Takao
T
Kimura
Kazumi
K
D000208:Acute Disease / Q000453:epidemiology; D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000502:physiology; D015897:Comorbidity; D004452:Echocardiography; D019320:Embolism, Paradoxical / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000503:physiopathology; D005260:Female; D054092:Foramen Ovale, Patent / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000503:physiopathology; D006801:Humans; D020766:Intracranial Embolism / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000503:physiopathology; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D011655:Pulmonary Embolism / Q000453:epidemiology; D012307:Risk Factors; D017678:Sex Distribution; D020521:Stroke / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000503:physiopathology; D017585:Ultrasonography, Doppler, Transcranial; D020246:Venous Thrombosis / Q000453:epidemiology