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Updated: Feb 7, 2026
Evaluation of Cerebral Blood Flow Autoregulation in the Rat Using Laser Doppler Flowmetry
Published on: January 19, 2020
Incomplete recovery of cerebral blood flow dynamics in sufficiently treated high blood pressure
Martin Müller1, Mareike Österreich1, Alexander von Hessling2
1Department of Neurology and Neurorehabilitation.
Insights
Cerebrovascular regulation is impaired in patients with high blood pressure and small vessel disease, affecting blood flow changes and variability distribution.
Area of Science:
- Neurology
- Cardiovascular Science
- Medical Imaging
Background:
- High blood pressure (HBP) and small vessel disease (SVD) are common conditions affecting cerebrovascular health.
- Understanding cerebrovascular regulation in HBP patients with SVD is crucial for managing stroke risk.
- Previous studies have explored blood flow regulation but often lack detailed analysis of SVD impact.
Purpose of the Study:
- To investigate differences in cerebrovascular regulation between patients with controlled high blood pressure (HBP) with and without small vessel disease (SVD).
- To assess the relationship between blood pressure variability (BPV) and cerebral blood flow velocity (CBFV) in these patient groups.
- To determine if autoregulation indices differ based on the presence and severity of SVD.
Main Methods:
- Simultaneous recordings of blood pressure (BP), cerebral blood flow velocity (CBFV) in middle cerebral arteries (MCAs), and end-tidal CO2 (ETCO2) were performed.
- Analysis included coherence and transfer function gain/phase between BP and CBFV in very low (VLF), low, and high frequency ranges.
- Blood pressure variability (BPV) was quantified using standard deviation (SD) of BP.
Main Results:
- In healthy controls, autoregulation indices were not age-dependent, but BPV correlated with CBFV regulation across different frequencies.
- HBP patients with SVD showed some differences in gain compared to those without SVD.
- Compared to age-matched controls, HBP patients exhibited increased VLF coherence and gain, and altered phase responses, with BPV showing specific correlations with CBFV regulation in the left MCA.
Conclusions:
- Cerebral blood flow (CBF) regulation is compromised in controlled HBP, particularly concerning long-lasting changes, in the presence of SVD.
- Blood pressure variability effects on CBF regulation lose their physiological bilateral distribution in HBP patients with SVD.
- Phase appears to be a reliable, age-independent index of autoregulation.
Objective:
Whether cerebrovascular regulation is different in patients with controlled high blood pressure (HBP) with and without small vessel disease (SVD).
Methods:
Sixty-seven healthy controls (mean age ± SD, 45 ± 16 years; 30 women, 37 men) and 40 patients (mean age, 64 ± 13 years; 14 women, 26 men) with HBP and different stages of SVD, underwent simultaneous recordings of the spontaneous fluctuations of BP, blood flow velocity (CBFV) in both middle cerebral arteries (MCA), and of end-tidal CO2 (ETCO2). Coherence and transfer function gain and phase between BP and CBFV were assessed in the frequency ranges of VLF (0.02-0.07 Hz), low frequency (0.07-0.15), and high frequency (>0.15). BP SD indicated BP variability (BPV).
Results:
In controls (BP, 86 ± 13 mmHg; ETCO2, 39 ± 4 mmHg; BPV, 15 ± 6 mmHg), gain, phase and coherence were not age-dependent in simple or a multiple regression models. BPV correlated significantly in both MCAs with gain in low frequency and high frequency, and with phase in VLF and high frequency. In patients (BP, 91 ± 16 mmHg, ETCO2, 39 ± 4 mmHg, BPV 18 ± 5 mmHg), only gain showed some differences between different SVD groups. Comparing all patients with 25 controls of similar age and sex, patients exhibited significantly (P < 0.05-P < 0.005): increased coherence and gain in VLF, decreased phase in VLF and low frequency, correlations between BPV with phase in low frequency (left) and with gain in VLF (left) and in high frequency (left and right).
Conclusion:
Phase seems an age independent autoregulatory index. In controlled HBP, CBF regulation is degraded at longlasting CBF changes; BPV effects lose their physiological bilateral distribution.
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