TABLE 3.

Clinical, biometric, and echocardiographic assessed parameters across pre‐baseline, baseline and medium‐term follow‐up assessments in the switch and control groups.

	Pre‐baseline assessment to baseline assessment						Baseline assessment to medium‐term assessment
	Switch			Control			Switch			Control
	Bosentan + sildenafil			Bosentan + sildenafil			Bosentan + sildenafil switched to ambrisentan + tadalafil			Bosentan + sildenafil
	n	Δ	p	n	Δ	p	n	Δ	p	n	Δ	p
WHO FC**
III/IV (%)	‐	15 vs. 48*	<0.01		29 vs. 29	1.0	‐	48 vs. 21*	0.04	‐	29 vs. 50	0.30
Exercise assessment
6MWD (m)	24	1 [−33, 36]	0.94	8	−37 [−71, −3]*	0.04	26	8 [−14, 20]	0.47	5	26 [−16, 68]	0.16
Echocardiographic parameters
RAA (cm2)	10	1.8 [0.2, 3.5]*	0.03	6	0.4 [−1.7, 2.5]	0.66	13	0.5 [−0.8, 1.9]	0.42	8	2.3 [−1.8, 6.3]	0.23
RVSP (mmHg)	27	2 [−6, 10]	0.57	13	1.9 [−16.2, 19.9]	0.82	27	−3 [−11, 4]	0.39	13	9.4 [−2.6, 21.5]	0.11
Eccentricity index diastole	22	−0.05 [−0.17, 0.08]	0.45	10	−0.12 [−0.33, 0.08]	0.20	23	0.08 [−0.03, 0.18]	0.16	11	0.12 [−0.16, 0.40]	0.36
Eccentricity index systole	22	0.00 [−0.19, 0.18]	0.95	10	−0.10 [−0.64, 0.44]	0.69	24	0.63 [−0.50, 1.76]	0.26	11	0.37 [−0.17, 0.91]	0.16
TAPSE (mm)	21	1.1 [−0.5, 2.7]	0.17	9	1.7 [−1.3, 4.7]	0.23	24	0.8 [−0.6, 2.2]	0.22	10	2.6 [−6.8, 1.6]	0.19

Note: Data summarized as mean ± standard deviation. Comparison of parameters between assessments summarized as difference, Δ, confidence interval, [], number of paired pre/post data, n, and p‐value, p.

Key: Echocardiographic parameters: LVEI, left ventricular eccentricity index; RAA, right atrial area; RVSP, estimate of right ventricular systolic pressure on echocardiography; TAPSE, tricuspid annular plane systolic excursion. WHO FC, World Health Organization functional class.

^*=p < 0.05.

^**% of children in FC III or IV in those assigned.