Active regulation of cerebral venous tone: simultaneous arterial and venous transcranial Doppler sonography during a Valsalva manoeuvre

Abstract

The aim of this study was to analyse the cerebral venous outflow in relation to the arterial inflow during a Valsalva manoeuvre (VM). In 19 healthy volunteers (mean age 24.1 +/- 2.6 years), the middle cerebral artery (MCA) and the straight sinus (SRS) were insonated by transcranial Doppler sonography. Simultaneously the arterial blood pressure was recorded using a photoplethysmographic method. Two VM of 10 s length were performed per participant. Tracings of the variables were then transformed to equidistantly re-sampled data. Phases of the VM were analysed regarding the increase of the flow velocities and the latency to the peak. The typical four phases of the VM were also found in the SRS signal. The relative flow velocity (FV) increase was significantly higher in the SRS than in the MCA for all phases, particularly that of phase IV (p < 0.01). Comparison of the time latency of the VM phases of the MCA and SRS only showed a significant difference for phase I (p < 0.01). In particular, there was no significant difference for phase IV (15.8 +/- 0.29 vs. 16.0 +/- 0.28 s). Alterations in venous outflow in phase I are best explained by a cross-sectional change of the lumen of the SRS, while phases II and III are compatible with a Starling resistor. However, the significantly lager venous than the arterial overshoot in phase IV may be explained by the active regulation of the venous tone.

Evidence of active regulation of cerebral venous tone in individuals undergoing embolization of brain arteriovenous malformations

“…First, all measurements were obtained far from the area undergoing remodeling caused by hemodynamic overload because of the malformation (20). Second, active venous tone regulation is consistent with the data on blood flow velocities in the straight sinus and MCA of healthy volunteers during different phases of the Valsalva maneuver (30). In the straight sinus, this parameter was found to be twice as high as that in the MCA during phase IV (overshoot phase), which is generally associated with transient blood pressure elevation caused by sympathetic nervous system activation.…”

“…Until recently, the indirect evidence for active cerebral venous regulation mostly stemmed from histochemical studies showing the presence of aminergic nerve endings in the venous wall (9,14,23), as well as from in vitro studies demonstrating venous wall responses to certain agonists (13,17). In addition, a recent study on healthy volunteers has also demonstrated an active response of intracranial cerebral veins during the overshoot phase of the Valsalva maneuver (30). To further elucidate which of the mechanisms is operative, either active control through venous wall reactivity or passive blood outflow with involvement of hydrodynamic factors alone, the present study has been undertaken.…”

Jugular Valve Incompetence in Transient Global Amnesia. A Problem Revisited

“…). The unequivocal identification of the other phases requires averaging of several Doppler recordings . Furthermore, reflux defined as a flow direction toward the cranium was registered.…”

“…Effect of a Valsava Maneuver on the intracranial venous circulation. A) Schematic change of venous flow velocities during and after a Valsalva maneuver based on data of Stolz et al . B) Example of flow velocity measurement in the basal vein.…”

Relationship between cerebral arterial inflow and venous outflow during dynamic supine exercise

“…Importantly, some humans studies reported indicate that the cerebral veins may possess an active rather than passive regulation of cerebral venous tone under some situations (Stolz et al. , ; Ivanov et al. ).…”