Assessment of Dynamic Cerebral Autoregulation in Patients with Basilar Artery StenosisReport as inadecuate




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Background and Aims

Previous studies have shown impaired cerebral autoregulation CA in carotid and middle cerebral artery MCA stenosis-occlusion. Little is known about CA in patients with basilar artery BA stenosis. We therefore investigated dynamic CA patterns in BA stenosis using transfer function analysis TFA.

Methods

We measured spontaneous oscillations of blood flow velocity CBFV in the right posterior cerebral artery PCA, and left MCA and mean arterial pressure ABP continuously in 25 patients with BA stenosis moderate n=16 with 50-69% occlusion and severe n=9 with ≥70% occlusion and 22 healthy volunteers in supine position during 6 circles per minute deep breath. Analysis was based on the ‘black-box’ model of transfer function deriving phase and gain in both PCA and MCA.

Results

Though changes of phase shift and gain between the patients and healthy controls were observed in MCA, the differences are however not significant. Phase shift in PCA was significantly decreased in severe stenosis when comparing with healthy controls and moderate stenosis 4.2±34.2° VS 41.1±40.4°, 4.2±34.2° VS 34.2±27.2°, both p<0.05, whilst the gain in PCA is increased for moderate BA stenosis and decreased for severe BA stenosis. Furthermore, we found that phase shift were almost abolished in patients with ischemic stroke who developed unfavorable clinical outcome mRs>2 on the 90 days after stroke onset.

Conclusion

Dynamic CA in PCA reduces in patients with severe BA stenosis and those with ischemic stroke who present poor outcome in 90 days after stroke onset. Phase shift might be a sensitive index prompting impaired CA in posterior circulation.



Author: Xiping Gong, Jia Liu , Pei Dong, Pandeng Zhang, Na Li, Xingquan Zhao, Yongjun Wang

Source: http://plos.srce.hr/



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