Attenuated aortic–cerebral pulsatile transmission with posture-related increases in stroke volume in healthy young adults

Figures

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  Fig. 1. Experimental protocol and waveforms and spectra of AoP and MCAv. Panel A represents experimental protocol and postures. Following 5-min rest, 6 min of measurements of the middle cerebral artery blood velocity (MCAv) and radial artery pulse wave were performed, then, brachial blood pressure (BP) was measured. In panel B, averaged one-beat aortic pressure (AoP) and MCAv shows in upper left and right panels, respectively. Spectra of AoP and MCAv show in lower left and right panels, respectively.

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  Fig. 2. Stroke volume in each posture condition. Mean values are represented as bars in each condition. Individual data are presented as open circles and connected by solid lines among conditions. 60°, 30°, and 0° are the degree of backrest in each condition, and Leg condition was 0° backrest with elevated subject’s legs. Means and individual values were used data before statistical analysis (n = 15). The main effect of condition (P < 0.01) was detected using generalized linear mixed model analysis. * P < 0.05 vs. 60°. † P < 0.05 vs. 30°

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  Fig. 3. Spectra of aortic pressure and the middle cerebral artery blood velocity in each postural condition. All mean values (bar) and standard deviation were calculated from the values before statistical analysis (n = 15). Panels A and B represent the spectra of the aortic pressure and the middle cerebral artery blood velocity (MCAv), respectively. Tables below each figure shows frequencies of the corresponding heart rate (HR) harmonic. 60°, 30°, and 0° are the degree of backrest in each condition, and Leg condition was 0° backrest with elevated subject’s legs. The main effect of condition (P < 0.01 and P = 0.68 in AoP spectra and MCAv spectra, respectively) was detected using generalized linear mixed model analysis.

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  Fig. 4. Transfer function gain between aortic blood pressure and middle cerebral artery blood velocity in each postural condition. All mean values and standard deviation were calculated from the values before statistical analysis (n = 15). Panel A represents gain from the transfer function analysis between aortic blood pressure and the middle cerebral artery blood velocity. Each plot is the group data and error bar is standard deviation in each frequency. Panel B represents average values from 0.78 to 7.80 Hz in each condition. Bars represented mean values. Individual data are presented as open circles and connected by solid lines among conditions. 60°, 30°, and 0° are the degree of backrest in each condition, and Leg condition was 0° backrest with elevated subject’s legs. The main effect of condition (P < 0.01) was detected using generalized linear mixed model analysis. * P < 0.05 vs. 60°

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  Fig. 5. Repeated measures correlation between stroke volume (A), systemic vascular resistance (B), or cerebrovascular resistance index (C) and average gain from aortic pressure to middle cerebral artery blood velocity. Symbols differ among posture conditions and individual plots and regression lines are presented using different colors. 60°, 30°, and 0° are the degree of backrest in each condition, and Leg condition was 0° backrest with elevated subject’s legs. The relationships were detected using repeated measures correlation analysis. Data were n = 15.