Abstract 3392: Silent Cerebral Infarctions in Healthy Subjects with Right-Left Shunt on Transcranial Doppler
Background: In healthy elderly people, silent cerebral infarction (SCI) and white matter lesions are common, but little is known about their relevance. In the present study, we evaluated the association between SCI located outside the perforating artery territory and paradoxical embolism detected by agitated saline transcranial Doppler (TCD) monitoring in healthy subjects. We also compared the frequency and amount of paradoxical embolism between healthy subjects with SCI and acute stroke patients with presumed cryptogenic embolism.
Methods: This study is a prospective observational study undertaken from January 2009 to January 2011 by a university health promotion center and from January 2008 to January 2010 by a university stroke center. We defined SCI as evidence on MRI of one or more infarcts, without a history of a (corresponding) stroke or TIA; brain infarction was defined as a focal hyperintensity lesion 3 mm or large in diameter in the fluid-attenuation inversion recovery (FLAIR) images. We also evaluated neuroimaing indicators of microangiopathy, SCI within perforator territory and leukoaraiosis (LA), in all subjects.
Results: Among 1103 consecutive healthy adults who underwent MRI, 347 (31%) had one or more SCI. After excluding subjects with poor temporal window, refusal or having SCI within only striatocapsular area, 253 subjects underwent agitated saline TCD monitoring and 128 (51%) had right-to-left shunts (RLS). Similarly, 145 out of 234 patients (62%) with presumed cryptogenic embolic stroke showed RLS. However, RLS was less frequently observed in stroke patients with determined mechanisms (34 out of 94 patients (38%)) than healthy subjects with SCI (p=0.017). Moreover, the number of SCI within perforator territory and the degree of LA were inversely correlated with the amount of RLS in healthy subjects.
Conclusion: Our results suggest that paradoxical embolism plays an important role in the development of SCI outside the perforating artery territory in apparently healthy adult.
- © 2012 by American Heart Association, Inc.