Key result
Cardiopulmonary bypass preserves ~0.1 Hz cerebral vasomotor oscillations independent of systemic blood pressure.
Why the study?
This study tested whether ~ 0.1 Hz cerebral arteriole vasomotion is generated by intrinsic oscillations within brain arterioles rather than by external drive from systemic blood pressure oscillations (Mayer waves).
Do ultralow frequency (~0.1 Hz) cerebral artery vasomotor oscillations persist independently when systemic blood pressure oscillations (Mayer waves) are eliminated during cardiopulmonary bypass in patients undergoing cardiothoracic surgery?
Observational (n=16)
Single-blind (data analysis/peak selection was blinded to subject and surgical period)
No
Do ultralow frequency (~0.1 Hz) cerebral artery vasomotor oscillations persist independently when systemic blood pressure oscillations (Mayer waves) are eliminated during cardiopulmonary bypass in patients undergoing cardiothoracic surgery?
Using cardiopulmonary bypass to eliminate systemic Mayer waves in humans, this study provides direct physiological evidence that ~0.1 Hz cerebral blood flow oscillations are driven by intrinsic cerebrovascular vasomotion rather than systemic blood pressure fluctuations.
Answers are grounded in this paper and cite their sources.
Cerebral vasomotor oscillations persist independently on bypass; extends animal data but leaves open clinical monitoring relevance.
This study tests the hypothesis that vasomotion, an ∼ 0.1 Hz oscillation in arteriole diameter, is generated by intrinsic oscillations within the arterioles that perfuse the brain, and not by external drive from systemic blood pressure oscillations (Mayer waves). During cardio-pulmonary bypass that transiently eliminated systemic blood pressure oscillations in 14 patients, we observed that vasomotor oscillations persist with normal amplitudes and frequencies over the one- to three-hour time course of surgery. In contrast, ∼ 0.1 Hz oscillations in peripheral blood pressure were predominantly absent. This implies that cerebral arterioles generate their own rhythmic vaso-dynamics, although we cannot discount that vasomotion can phase-lock with ∼ 0.1 Hz systemic physiological rhythms in the awake, healthy state. We discuss the impact of this finding on the role of vasomotion in modulating the perfusion of blood and the transport of interstitial fluid in the brain.
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Alzetani et al. (2026) conducted an observational in Cardiothoracic surgical disease requiring surgery with or without cardiopulmonary bypass (n=16). Nonpulsatile cardiopulmonary bypass (CPB) vs. Pre-bypass (pre-CPB) surgical period with intact systemic blood pressure oscillations was evaluated on Occurrence of low-frequency (~0.1 Hz) vasomotor oscillation peaks in middle cerebral artery blood velocity power spectral density (p=0.19 (for vasomotor power pre-CPB vs on-CPB)). Cardiopulmonary bypass preserved ~0.1 Hz cerebral vasomotor oscillations in 86% of trials (104/121) versus 54% pre-bypass, with 92% showing no coherence with blood pressure.
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