Enhancing cerebral perfusion with external counterpulsation after ischaemic stroke: how long does it last?
OBJECTIVE
External counterpulsation (ECP) is a non-invasive method used to augment cerebral perfusion in ischaemic stroke. We aimed to investigate time-course effects on blood pressure elevation and cerebral blood flow augmentation induced by ECP in ischaemic stroke.


METHODS
Patients with acute unilateral ischaemic stroke and large artery occlusive disease were recruited to receive 35 daily 1 h ECP treatment sessions. Serial transcranial Doppler monitoring of bilateral middle cerebral arteries was performed on days 3, 5, 7, 10, 14, 21, 28 and 35 after stroke onset. Flow velocity changes before, during and after ECP and continuous beat-to-beat blood pressure data were recorded. The cerebral augmentation index (CAI) is the increase in the percentage of the middle cerebral artery mean flow velocity during ECP compared with baseline.


RESULTS
The CAI in patients with stroke was significantly higher on the ipsilateral side and on the contralateral side on day 3 (ipsilateral CAI, 9.3%; contralateral CAI, 7.2%), day 5 (7.0%; 6.7%), day 7 (6.8%; 6.0%), day 10 (6.0%; 5.1%), day 14 (4.7%; 2.6%) and day 21 (4.1%; 2.2%) after stroke onset than that in controls (-2.0%) (all p<0.05). There was a significant trend of decreasing CAI on the ipsilateral and contralateral sides over time after a stroke. Differences in the percentage increase in the mean blood pressure did not change significantly over time in patients with stroke.


CONCLUSIONS
Blood pressure elevation persists throughout ECP treatment, which consists of 35 sessions. However, cerebral blood flow augmentation may last at least 3 weeks and then appears to return to baseline 1 month after acute stroke onset.
Department of Medicine & Therapeutics, Chinese University of Hong Kong, Hong Kong, Hong Kong.
Li
L
Xiong
Department of Medicine & Therapeutics, Chinese University of Hong Kong, Hong Kong, Hong Kong.
Wenhua
W
Lin
Department of Medicine & Therapeutics, Chinese University of Hong Kong, Hong Kong, Hong Kong.
Jinghao
J
Han
Department of Medicine & Therapeutics, Chinese University of Hong Kong, Hong Kong, Hong Kong.
Xiangyan
X
Chen
Department of Medicine & Therapeutics, Chinese University of Hong Kong, Hong Kong, Hong Kong.
Thomas
T
Leung
Department of Medicine & Therapeutics, Chinese University of Hong Kong, Hong Kong, Hong Kong.
Yannie
Y
Soo
Department of Medicine & Therapeutics, Chinese University of Hong Kong, Hong Kong, Hong Kong.
Ka Sing
KS
Wong
D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D002545:Brain Ischemia / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D015908:Counterpulsation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000502:physiology; D020521:Stroke / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D017585:Ultrasonography, Doppler, Transcranial
CEREBRAL BLOOD FLOW; STROKE