Arterial wave reflection decreases gradually from supine to upright

Figures & data

Figure 1. Hemodynamics during different angles of tilt and standing. Data shown are mean ± standard error (SE) for aortic systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), stroke volume (SV), cardiac output (CO), total peripheral resistance (TPR).

Figure 2. Arterial wave reflection during different angles of tilt and standing. Data shown are mean ± standard error (SE) for augmentation index (AIx) and reflection magnitude (RM).

Table I. Hemodynamic and arterial wave reflection data.

	0°	30°	70°	90°	ANOVA p
SBP, mm Hg	116.3	115.0	113.0	115.1	0.43
DBP, mm Hg	72.6	80.6**	82.9**	82.3**	<0.001
MAP, mm Hg	93.9	98.8*	97.6*	98.8*	<0.01
HR, beats/min	54.2	61.7*	74.7**	75.5**	<0.001
SV, ml	90	73.5*	53**	55**	<0.001
CO, l/min	5.1	4.9	4.1*	4.0**	<0.01
TPR, dyn s/cm^5	0.937	1.189*	1.427**	1.418**	<0.001
AIx, %	25	16*	−1**	−10**	<0.001
RM	0.572	0.551	0.469**	0.456**	<0.001
Pf	34.9	32.5	29.9*	30.2**	0.01
Pb	20.0	17.8	14.0**	13.7**	<0.001

Data shown are medians for aortic systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), stroke volume (SV), cardiac output (CO), total peripheral resistance (TPR), augmentation index (AIx), reflection magnitude (RM), forward pressure wave (Pf) and backward pressure wave (Pb). Differences between the different angles of tilt were calculated using Friedman's analysis of variance (ANOVA) with post hoc comparison with supine (0°) with Wilcoxon signed rank test. *p < 0.05 vs 0°, **p < 0.01 vs 0°.

Figure 3. Measured (solid lines), forward (interrupted lines) and backward (dotted lines) pressure waves during different angles of tilt and standing.