TABLE 3.

Characteristics of the arterial tree and of the forward and backward pressure waveforms as derived from the wave separation analysis according to the BWTT quartiles.

	Backward wave transit time				P-value
	Q1 (n = 87)	Q2 (n = 88)	Q3 (n = 88)	Q4 (n = 88)
Arterial tree
Systemic vascular resistance (mmHg/ml)	1.65 ± 0.64	1.45 ± 0.54	1.50 ± 0.47	1.27 ± 0.46	<0.001
Total arterial compliance (ml⋅ mmHg–1)	0.49 ± 0.25	0.58 ± 0.31	0.58 ± 0.28	0.61 ± 0.25	0.041
Characteristic impedance of the aorta (mmHg/ml)	0.14 ± 0.06	0.17 ± 0.08	0.18 ± 0.08	0.18 ± 0.07	0.002
Wave separation analysis
Forward wave amplitude (mmHg)	49 ± 13	49 ± 15	48 ± 16	48 ± 16	0.841
Time to forward wave peak (ms)	258 ± 43	250 ± 40	258 ± 46	251 ± 44	0.465
Backward wave amplitude (mmHg)	33 ± 11	28 ± 9	27 ± 10	25 ± 9	<0.001
Time to backward wave peak (ms)	294 ± 47	305 ± 51	329 ± 65	354 ± 62	<0.001
Backward wave transit time (ms)	40 ± 9	55 ± 8	77 ± 11	117 ± 23	<0.001
Reflection coefficient (%)	66 ± 13	59 ± 10	58 ± 12	53 ± 10	<0.001

Continuous variables expressed as mean ± standard deviation. P-values obtained by ANOVA.