Influence of Temporal Insonation Window Quality on the Assessment of Cerebral Autoregulation with Transcranial Doppler Sonography

Lorenz, Matthias; Gonzalez, M.; Lienerth, Christian; Loesel, Nadine; Thoelen, Nina; Sitzer, Matthias

doi:10.1016/j.ultrasmedbio.2007.04.010

Cited by 12 publications

(18 citation statements)

References 23 publications

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“…Previous studies have assessed the repeatability by comparing the first and last half of recordings, reporting poor to moderate repeatability (Lorenz et al, 2007(Lorenz et al, , 2008. This pattern applies to all approaches in the present study.…”

Section: Discussionmentioning

confidence: 60%

“…The reliability of Mxa has previously been assessed in healthy volunteers in several studies, which have reported highly variable repeatability and reproducibility ranging from poor to excellent (Chi et al, 2018;Lee et al, 2020;Lorenz et al, 2007;Mahdi, Nikolic, Birch, Olufsen, et al, 2017), and from poor to good (Lorenz et al, 2008;Ortega-Gutierrez et al, 2014;Riberholt et al, 2021), respectively. As a potential explanation, these studies utilized short recordings, often shorter than 6 min, the minimum duration necessary for Mxa to stabilize according to one study .…”

Section: Introductionmentioning

confidence: 99%

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Reliability of the mean flow index (Mx) for assessing cerebral autoregulation in healthy volunteers

et al. 2021

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Section: Discussionmentioning

confidence: 60%

Section: Introductionmentioning

confidence: 99%

Reliability of the mean flow index (Mx) for assessing cerebral autoregulation in healthy volunteers

et al. 2021

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“…First, there was no DW-MRI data to confirm the effect of higher embolization rates on new structural brain lesions postintervention as shown in previous research. 35 Second, the number of dropouts due to insonation problems was high, especially in older women, although this is a problem inherent to the TCD technique 15,16 and is not specific to this study. A third limitation was the limited number of patients.…”

Section: Limitationsmentioning

confidence: 86%

“…Of the 48 patients with significant internal carotid artery stenosis (≥80% for asymptomatic and ≥60% for symptomatic cases on duplex ultrasound) and no ostial CCA or tandem lesions enrolled in this study, TCD could not be performed in 14 patients due to practical difficulties or an inadequate transtemporal insonation window, mostly in older women. 15,16 Thus, the analysis focuses on 34 patients (mean age 67.6 years; 24 men) who were monitored with TCD throughout the entire carotid revascularization procedure (10 CEA, 8 CASdp, and 16 CASfr). The Ghent University Hospital Ethical Committee approved this study, and all participants gave written informed consent.…”

Section: Patient Samplementioning

confidence: 99%

Transcervical Carotid Stenting With Dynamic Flow Reversal Demonstrates Embolization Rates Comparable to Carotid Endarterectomy

et al. 2016

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TCD recordings demonstrated a significant reduction in embolization to the brain during transcervical carotid artery stent placement with the use of dynamic flow reversal compared to transfemoral CAS using distal filters. No significant differences in microembolization could be detected between CEA and CASfr. The observed lower embolization rates and lack of adverse events suggest that transcervical CAS with dynamic flow reversal is a promising technique and may be the preferred method when performing CAS.

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“…Although spatial heterogeneity of cerebral autoregulation as well as interhemispheric differences are well described [39], an endpoint of this study was not to define interhemispheric differences, but rather to ensure the best transcranial Doppler recordings in order to minimize the signal-to-noise ratio and increase data reliability [40]. …”

Section: Discussionmentioning

confidence: 99%

Intraaortic Balloon Pump Counterpulsation and Cerebral Autoregulation: an observational study

et al. 2010

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BackgroundThe use of Intra-aortic counterpulsation is a well established supportive therapy for patients in cardiac failure or after cardiac surgery. Blood pressure variations induced by counterpulsation are transmitted to the cerebral arteries, challenging cerebral autoregulatory mechanisms in order to maintain a stable cerebral blood flow. This study aims to assess the effects on cerebral autoregulation and variability of cerebral blood flow due to intra-aortic balloon pump and inflation ratio weaning.MethodsCerebral blood flow was measured using transcranial Doppler, in a convenience sample of twenty patients requiring balloon counterpulsation for refractory cardiogenic shock (N = 7) or a single inotrope to maintain mean arterial pressure following an elective placement of an intra-aortic balloon pump for cardiac surgery (N = 13). Simultaneous blood pressure at the aortic root was recorded via the intra-aortic balloon pump. Cerebral blood flow velocities were recorded for six minute intervals at a 1:1 balloon inflation-ratio (augmentation of all cardiac beats) and during progressive reductions of the inflation-ratio to 1:3 (augmentation of one every third cardiac beat). Real time comparisons of peak cerebral blood flow velocities with systolic blood pressure were performed using cross-correlation analysis. The primary endpoint was assessment of cerebral autoregulation using the time delay between the peak signals for cerebral blood flow velocity and systolic blood pressure, according to established criteria. The variability of cerebral blood flow was also assessed using non-linear statistics.ResultsDuring the 1:1 inflation-ratio, the mean time delay between aortic blood pressure and cerebral blood flow was -0.016 seconds (95% CI: -0.023,-0.011); during 1:3 inflation-ratio mean time delay was significantly longer at -0.010 seconds (95% CI: -0.016, -0.004, P < 0.0001). Finally, upon return to a 1:1 inflation-ratio, time delays recovered to those measured at baseline. During inflation-ratio reduction, cerebral blood flow irregularities reduced over time, whilst cerebral blood flow variability at end-diastole decreased in patients with cardiogenic shock.ConclusionsWeaning counterpulsation from 1:1 to 1:3 inflation ratio leads to a progressive reduction in time delays between systolic blood pressure and peak cerebral blood flow velocities suggesting that although preserved, there is a significant delay in the establishment of cerebral autoregulatory mechanisms. In addition, cerebral blood flow irregularities (i.e. surrogate of flow adaptability) decrease and a loss of cerebral blood flow chaotic pattern occurs during the end-diastolic phase of each beat in patients with cardiogenic shock.

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Influence of Temporal Insonation Window Quality on the Assessment of Cerebral Autoregulation with Transcranial Doppler Sonography

Cited by 12 publications

References 23 publications

Reliability of the mean flow index (Mx) for assessing cerebral autoregulation in healthy volunteers

Reliability of the mean flow index (Mx) for assessing cerebral autoregulation in healthy volunteers

Transcervical Carotid Stenting With Dynamic Flow Reversal Demonstrates Embolization Rates Comparable to Carotid Endarterectomy

Intraaortic Balloon Pump Counterpulsation and Cerebral Autoregulation: an observational study

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