TY - JOUR
T1 - Contribution of arterial Windkessel in low-frequency cerebral hemodynamics during transient changes in blood pressure
AU - Chan, Gregory S.H.
AU - Ainslie, Philip N.
AU - Willie, Chris K.
AU - Taylor, Chloe E.
AU - Atkinson, Greg
AU - Jones, Helen
AU - Lovell, Nigel H.
AU - Tzeng, Yu Chieh
PY - 2011/4/1
Y1 - 2011/4/1
N2 - Contribution of arterial Windkessel in low-frequency cerebral hemodynamics during transient changes in blood pressure. J Appl Physiol 110: 917-925, 2011. First published February 3, 2011; doi:10.1152/japplphysiol.01407.2010.-The Windkessel properties of the vasculature are known to play a significant role in buffering arterial pulsations, but their potential importance in dampening low-frequency fluctuations in cerebral blood flow has not been clearly examined. In this study, we quantitatively assessed the contribution of arterial Windkessel (peripheral compliance and resistance) in the dynamic cerebral blood flow response to relatively large and acute changes in blood pressure. Middle cerebral artery flow velocity (MCAV; transcranial Doppler) and arterial blood pressure were recorded from 14 healthy subjects. Low-pass-filtered pressureflow responses ( < 0.15 Hz) during transient hypertension (intravenous phenylephrine) and hypotension (intravenous sodium nitroprusside) were fitted to a two-element Windkessel model. The Windkessel model was found to provide a superior goodness of fit to the MCAV responses during both hypertension and hypotension (R2 = 0.89 ± 0.03 and 0.85 ± 0.05, respectively), with a significant improvement in adjusted coefficients of determination (P < 0.005) compared with the single-resistance model (R 2 = 0.62 ± 0.06 and 0.61 ± 0.08, respectively). No differences were found between the two interventions in the Windkessel capacitive and resistive gains, suggesting similarvascular properties during pressure rise and fall episodes. The results highlight that low-frequency cerebral hemodynamic responses to transient hypertension and hypotension may include a significant contribution from the mechanical properties of vasculature and, thus, cannot solely be attributed to the active control of vascular tone by cerebral autoregulation. The arterial Windkessel should be regarded as an important element of dynamic cerebral blood flow modulation during large and acute blood pressure perturbation.
AB - Contribution of arterial Windkessel in low-frequency cerebral hemodynamics during transient changes in blood pressure. J Appl Physiol 110: 917-925, 2011. First published February 3, 2011; doi:10.1152/japplphysiol.01407.2010.-The Windkessel properties of the vasculature are known to play a significant role in buffering arterial pulsations, but their potential importance in dampening low-frequency fluctuations in cerebral blood flow has not been clearly examined. In this study, we quantitatively assessed the contribution of arterial Windkessel (peripheral compliance and resistance) in the dynamic cerebral blood flow response to relatively large and acute changes in blood pressure. Middle cerebral artery flow velocity (MCAV; transcranial Doppler) and arterial blood pressure were recorded from 14 healthy subjects. Low-pass-filtered pressureflow responses ( < 0.15 Hz) during transient hypertension (intravenous phenylephrine) and hypotension (intravenous sodium nitroprusside) were fitted to a two-element Windkessel model. The Windkessel model was found to provide a superior goodness of fit to the MCAV responses during both hypertension and hypotension (R2 = 0.89 ± 0.03 and 0.85 ± 0.05, respectively), with a significant improvement in adjusted coefficients of determination (P < 0.005) compared with the single-resistance model (R 2 = 0.62 ± 0.06 and 0.61 ± 0.08, respectively). No differences were found between the two interventions in the Windkessel capacitive and resistive gains, suggesting similarvascular properties during pressure rise and fall episodes. The results highlight that low-frequency cerebral hemodynamic responses to transient hypertension and hypotension may include a significant contribution from the mechanical properties of vasculature and, thus, cannot solely be attributed to the active control of vascular tone by cerebral autoregulation. The arterial Windkessel should be regarded as an important element of dynamic cerebral blood flow modulation during large and acute blood pressure perturbation.
UR - http://www.scopus.com/inward/record.url?scp=79954577271&partnerID=8YFLogxK
U2 - 10.1152/japplphysiol.01407.2010
DO - 10.1152/japplphysiol.01407.2010
M3 - Article
C2 - 21292835
AN - SCOPUS:79954577271
SN - 8750-7587
VL - 110
SP - 917
EP - 925
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
IS - 4
ER -