Cardiac right-to-left shunt subtypes in Chinese patients with cryptogenic strokes: a multicenter case-control study.
OBJECTIVE
Data on the possible association between cardiac right-to-left shunt (RLS) and cryptogenic stroke are lacking in Asians. RLS and its subtypes in Chinese cryptogenic stroke patients were investigated.


METHODS
Patients (n = 153, mean age 42 ± 10 years, 81 male) with cryptogenic stroke from four medical centers in China and 135 healthy volunteers (mean age 34 ± 8 years, 54 male) were recruited. Contrast transcranial Doppler was used to assess the prevalence of RLS. A three-level RLS categorization was applied as follows: none, 0 microbubbles (MBs); small, 1-25 MBs; and large, >25 MBs. RLS was considered latent if it occurred only after the Valsalva maneuver or permanent when it occurred also during normal respiration.


RESULTS
Overall, RLS (P = 0.02), large RLS (P < 0.001) and permanent RLS (P = 0.02) were more frequently detected in patients with cryptogenic stroke than in healthy volunteers. The prevalences of small RLS and latent RLS in the two groups were similar (22% vs. 21% and 11% vs. 10%, respectively). The proportion of large RLSs amongst the subjects with RLS was much higher in the patient group than in healthy volunteers (45% vs. 18%, P < 0.001), whilst the proportion of permanent RLS was similar (72% vs. 64%, P = 0.11). Most large RLSs in the patient group (22/27, 81%) were permanent RLSs.


CONCLUSIONS
Cardiac RLS is associated with cryptogenic stroke in Chinese. However, the higher prevalence of overall RLS in the patient group was mainly due to the increased proportion of large RLSs. The results only support large RLSs as a pathological condition.
Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China.
W H
WH
Xu
Y Q
YQ
Xing
Z R
ZR
Yan
J D
JD
Jiang
S
S
Gao
D000328:Adult; D001166:Arteriovenous Shunt, Surgical / Q000379:methods*; D044466:Asian People; D016022:Case-Control Studies; D005260:Female; D054092:Foramen Ovale, Patent / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery*; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D020521:Stroke / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D017585:Ultrasonography, Doppler, Transcranial; D055815:Young Adult
Chinese population; patent foramen ovale; stroke; transcranial Doppler