Impaired cerebral autoregulation: measurement and application to stroke

Xiong, Li; Liu, Xiuyun; Shang, Ty; Smielewski, Peter; Donnelly, Joseph E.; Z, Guo; Yang, Yi; Leung, Thomas W.; Czosnyka, Marek; Zhang, Rong; Liu, Jia; Wong, Ka Sing

doi:10.1136/jnnp-2016-314385

Cited by 118 publications

(113 citation statements)

References 66 publications

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“…It is postulated that acute stroke particularly with underlying carotid stenosis is characterized by impaired cerebral autoregulation which in turn predisposes the patient to hyperperfusion syndrome after CEA. 9,16 Our data seem to support this hypothesis, but there are also other factors that may explain the finding. In our hospital, patients are treated in a semi-intensive stroke unit at least 24 hours after IVT and if early operated on, they commonly return to the stroke unit after surgery and are continuously monitored.…”

Section: Discussionsupporting

confidence: 68%

Prior Intravenous Stroke Thrombolysis Does Not Increase Complications of Carotid Endarterectomy

Ijäs

Aro

Eriksson

et al. 2018

Stroke

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Background and Purpose- Carotid endarterectomy (CEA) is recommended within 14 days after carotid artery stroke to prevent recurrence. However, the optimal timing of CEA after intravenous thrombolysis (IVT) remains unclear. We studied the safety of CEA after IVT while taking into account both stroke recurrence and CEA-related complications. Methods- Patients who underwent IVT followed by CEA in Helsinki University Hospital 2005 to 2016 were withdrawn from prospectively collected registers. The incidence of stroke recurrence during the time between IVT and CEA, peri/postoperative stroke, hyperperfusion syndrome or drug-resistant high blood pressure, and 3-month outcome measured by modified Rankin Scale was recorded. Stroke patients treated with CEA without preceding IVT were used as controls. Results- Altogether 128 CEAs with preceding IVT and 777 CEAs for stroke without IVT were identified. The median time from IVT to CEA was 9 days (range, 0-349 days; interquartile range, 16). Seven patients (5.5%) underwent CEA within 24 hours, 20 (15.6%) within 48 hours and 87 (68.0%) within 2 weeks from IVT. Stroke recurrence in IVT-CEA patients was 5.5% at median 4 days after IVT (range, 0-8 days). Outcome from CEAs performed within 48 hours from IVT did not differ from CEAs performed later with respect to peri/postoperative ischemic strokes (5.0% and 3.7%), hemorrhagic strokes (5.0% and 1.9%), neck hematomas (5.0% and 8.3%), myocardial infarctions (0.0% and 0.9%), or 3-month modified Rankin Scale. There was a tendency toward higher incidence of hyperperfusion syndrome in the patients operated within 48 hours from IVT (20.0% versus 6.5%; P=0.070). The CEA-related stroke rate was similar to that of the operation without thrombolysis. Only smoking was significantly associated with peri/postoperative stroke (odds ratio, 21.82; 95% confidence interval, 1.08-439.58). Conclusions- Time between IVT and CEA was not associated with CEA-related complications. The high rate of stroke recurrence during the waiting time for CEA underscores the importance of shortening surgery delays.

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Section: Discussionsupporting

confidence: 68%

Prior Intravenous Stroke Thrombolysis Does Not Increase Complications of Carotid Endarterectomy

Ijäs

Aro

Eriksson

et al. 2018

Stroke

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“…Dynamic cerebral autoregulation (dCA) is a pivotal mechanism to maintain stable cerebral hemodynamics [11].…”

Section: Introductionmentioning

confidence: 99%

Dynamic cerebral autoregulation is an independent outcome predictor of acute ischemic stroke after endovascular therapy

et al. 2020

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Background: Endovascular therapy (EVT) is increasingly used to improve cerebral reperfusion after moderate-tosevere acute ischemic stroke (AIS). However, the influence of hemodynamic factors on clinical outcome is still unclear after EVT. Dynamic cerebral autoregulation (dCA) is an important brain reserve mechanism and is impaired after AIS. This study aimed to explore the role of dCA in predicting the outcome of AIS patients after EVT.Methods: AIS patients with severe stenosis/occlusion of unilateral middle cerebral artery (MCA) or internal carotid and treatment with EVT were enrolled to receive dCA examinations at the 24 h, 72 h and 7th day after stroke onset. Healthy volunteers were also recruited as controls. DCA was recorded from spontaneous fluctuations of blood pressure and MCA flow velocity. Transfer function analysis was used to derive dCA parameters, including phase difference (PD) and coherence in the low-frequency range (0.06-0.12 Hz). The clinical outcome was measured using the modified Rankin Scale (mRS) at 90 days after onset. Multivariate logistic regression was performed to reveal the correlation between dCA and clinical outcomes. The receiver operation characteristics (ROC) curve was performed to determine the cut-off point of PD. Results: A total of 62 AIS patients and 77 healthy controls were included. Compared with controls, dCA were impaired bilaterally till to 7th day after onset in patients, presenting as much lower PD value on the ipsilateral side. During followup, we found that PD on the ipsilateral side at 24 h after onset was significantly lower in patients with unfavourable outcome (n = 41) than those with favourable outcome (n = 21), even after adjustment of confounding factors (p = 0.009). ROC curve analysis revealed that PD < 26.93°was an independent predictor of unfavourable-outcome. Conclusion:In AIS patients after EVT, dCA was impaired on both sides over the first 7 days. PD on the ipsilateral side at 24 h after onset is an independent unfavourable-outcome predictor for AIS after EVT.

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“…Determining if dynamic CA has a directional or asymmetrical behavior is highly relevant for both improving our understanding of the underlying physiology and potentially optimizing the current methods of assessment (13,37). If dynamic CA is proven to show asymmetry in relation to BP changes, this will impact the current modeling techniques used to quantify dynamic CA in health and disease, as methods will be required to take into account the directionality of BP changes.…”

Section: Introductionmentioning

confidence: 99%

Directional sensitivity of dynamic cerebral autoregulation in squat-stand maneuvers

Panerai

Barnes

Nath

et al. 2018

American Journal of Physiology-Regulatory, Integrative and Comp

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Dynamic cerebral autoregulation (CA), the transient response of cerebral blood flow (CBF) to rapid changes in arterial blood pressure (BP), is usually modeled as a linear mechanism. We tested the hypothesis that dynamic CA can display nonlinear behavior resulting from differential efficiency dependent on the direction of BP changes. Cerebral blood velocity (CBV) (transcranial Doppler), heart rate (HR) (three-lead ECG), continuous BP (Finometer), and end-tidal CO (capnograph) were measured in 10 healthy young subjects during 15 squat-stand maneuvers (SSM) with a frequency of 0.05 Hz. The protocol was repeated with a median (interquartile range) of 44 (35-64) days apart. Dynamic CA was assessed with the autoregulation index (ARI) obtained from CBV step responses estimated with an autoregressive moving-average model. Mean BP, HR, and CBV were different (all P < 0.001) between squat and stand, regardless of visits. ARI showed a strong interaction ( P < 0.001) of SSM with the progression of transients; in general, the mean ARI was higher for the squat phase compared with standing. The changes in ARI were partially explained by concomitant changes in CBV ( P = 0.023) and pulse pressure ( P < 0.001), but there was no evidence that ARI differed between visits ( P = 0.277). These results demonstrate that dynamic CA is dependent on the direction of BP change, but further work is needed to confirm if this finding can be generalized to other physiological conditions and also to assess its dependency on age, sex and pathology.

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Impaired cerebral autoregulation: measurement and application to stroke

Cited by 118 publications

References 66 publications

Prior Intravenous Stroke Thrombolysis Does Not Increase Complications of Carotid Endarterectomy

Prior Intravenous Stroke Thrombolysis Does Not Increase Complications of Carotid Endarterectomy

Dynamic cerebral autoregulation is an independent outcome predictor of acute ischemic stroke after endovascular therapy

Directional sensitivity of dynamic cerebral autoregulation in squat-stand maneuvers

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