Key Points
- To evaluate pressure and flow relations, impedance spectra, and hydraulic power distribution across the aortic arch under baseline and autonomic nerve stimulation conditions.
- Measured simultaneous pressure and flow in the ascending aorta, descending thoracic aorta, brachiocephalic, left subclavian, and common carotid arteries of chloralose-anesthetized dogs.
- Evaluated hemodynamics across three conditions: baseline control, cardiac sympathetic stimulation, and vagal nerve stimulation.
- Applied Fourier series analysis to quantify vascular impedance spectra, harmonic propagation characteristics, and hydraulic power dissipation.
- Baseline cardiac output was distributed 70% to the descending thoracic aorta, 22.2% to the brachiocephalic artery, and 6.5% to the left subclavian artery, with both sympathetic and vagal stimulation increasing the proportion delivered to cranial branches.
- Vascular wall dissipation consumed an average of 6% of ascending aorta hydraulic power, which increased during sympathetic stimulation and decreased during vagal stimulation.
- Impedance spectra and harmonic transmission patterns were consistent across arterial sites and neural states, indicating that major wave reflections do not occur in the proximal aorta.
Structured PICO
PPopulationChloralose-anesthetized dogs
IInterventionCardiac sympathetic (SS) and vagal nerve stimulation (VS)
CComparatorControl condition
OOutcomePressure and flow relations, vascular impedance spectra, pressure and flow propagation characteristics, and hydraulic power in the vessels of the aortic archsurrogate
In a canine model, autonomic nerve stimulation altered the distribution of cardiac output and hydraulic power to the aortic arch vessels, suggesting viscous losses in arterial walls represent significant power dissipation without major reflections in the proximal aorta.