Cerebral emboli and paradoxical embolisation in dementia: a pilot study.
BACKGROUND
The causes of the common dementias remain unknown. Paradoxical embolisation of the cerebral circulation by venous thrombi passing through venous to arterial shunts (v-aCS) in the heart or pulmonary circulation is known to occur in cryptogenic stroke and post-operative confusion following hip replacement.


OBJECTIVE
To explore the role of paradoxical embolisation in dementia by investigating for cerebral emboli, venous to arterial circulation shunt (v-aCS) and carotid artery disease.


METHODS
Forty-one patients with dementia (24 Alzheimer's AD and 17 vascular VaD) diagnosed using DSM-IV criteria and 16 controls underwent transcranial Doppler (TCD) detection of spontaneous cerebral emboli in both middle cerebral arteries. A v-aCS was detected by intravenous injection of an air/saline ultrasound contrast at rest and after provocation by coughing and Valsalva's manoeuvre. Carotid artery disease was assessed by duplex imaging.


RESULTS
Cerebral emboli were detected in 11 (27.5%) dementia patients compared with one (7%) control (p = 0.15) with emboli being most frequent in VaD (41%) compared to controls [OR (95% CI): 10.5 (1.1, 98.9), p = 0.04]. A v-aCS was detected in 25 (61%) patients and seven (44%) controls (p = 0.24). In dementia patients with cerebral emboli; v-aCS was detected in seven (64%) and moderate to severe carotid stenosis was present in three (30%).


CONCLUSIONS
Cerebral emboli and v-aCS may be more frequent in patients with both VaD and AD than in controls, which suggest paradoxical embolisation as a potential mechanism for cerebral damage. This pilot study justifies a definitive case-control study.
Purandare
Nitin
N
University of Manchester, School of Psychiatry and Behavioural Sciences, Education and Research Centre, Wythenshawe Hospital, Wythenshawe, Manchester M23 9LT, UK. nitin.purandare@man.ac.uk
Welsh
Sarah
S
Hutchinson
Susanne
S
Riding
Graham
G
Burns
Alistair
A
McCollum
Charles
C
D000368:Aged; D000544:Alzheimer Disease / Q000000981:diagnostic imaging / Q000209:etiology; D001163:Arteriovenous Anastomosis / Q000000981:diagnostic imaging*; D002340:Carotid Artery Diseases / Q000150:complications / Q000000981:diagnostic imaging*; D002536:Cerebral Arteries / Q000000981:diagnostic imaging*; D002560:Cerebrovascular Circulation; D003287:Contrast Media; D003704:Dementia / Q000000981:diagnostic imaging* / Q000209:etiology; D015140:Dementia, Vascular / Q000000981:diagnostic imaging / Q000209:etiology; D005260:Female; D006801:Humans; D020766:Intracranial Embolism / Q000150:complications / Q000000981:diagnostic imaging*; D008297:Male; D010865:Pilot Projects; D018616:Ultrasonography, Doppler, Duplex / Q000379:methods; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods
D003287:Contrast Media