Table 2

Changes in gas exchange parameters, biventricular function and haemodynamics from rest to peak exercise before and after sildenafil administration

	Controls (n=7)			CTEPH (n=14)
	Pre-sildenafil	Post-sildenafil	p Value	Pre-sildenafil	Post-sildenafil	p Value
Heart rate, bpm
Rest	61±3	78±4	0.002	79±3*	82±3	0.152
Peak exercise	147±4†	153±7†	0.186	122±5†*	118±5†*	0.038
LVEF, %
Rest	60.7±2.1	65.6±2.6	0.072	61.0±2.5	63.5±2.2	0.004
Peak exercise	69.6±1.6†	73.0±1.7†	0.044	64.1±3.6	67.4±3.2†	0.006
RVEF, %
Rest	59.1±2.3	62.5±3.3	0.268	36.2±1.8*	40.1±1.9*	<0.001
Peak exercise	73.2±1.9†	75.3±3.2†	0.436	34.8±2.2*	40.0±3.0*	0.002
SVi, mL/m²
Rest	53±5	50±5	0.370	35±2*	37±2*	0.036
Peak exercise	59±6	57±6	0.462	34±3*	39±3*	0.009
CI, L/min m²
Rest	3.1±0.3	3.7±0.2	0.019	2.7±0.2	2.9±0.2*	0.006
Peak exercise	8.7±1.1†	8.8±1.2†	0.692	4.1±0.3†*	4.5±0.2†*	0.021
mSAP, mm Hg
Rest	101±5	91±5	0.058	94±4	83±3	0.001
Peak exercise	125±3†	118±4†	0.062	117±6†	105±5†	0.001
mPAP, mm Hg
Rest	11±1	8±1	0.012	45±3*	38±2*	<0.001
Peak exercise	24±3†	19±1†	0.026	64±3.0†*	54±3.0†*	<0.001
RA pressure, mm Hg
Rest	−	−		8±2	6±2	0.044
Peak exercise	−	−		19±3†	14±4†	0.017
tPVR dyne/s/cm⁵
Rest	154±23	97±11	0.012	727±53*	553±41*	<0.001
Peak exercise	126±22	95±11	0.105	688±63*	527±53*	<0.001
tSVR, dyne/s/cm⁵
Rest	1483±217	1072±108	0.012	1565±154	1227±104	<0.001
Peak exercise	661±86†	639±114†	0.641	1271±136†*	1031±109†*	0.001
tPVR/tSVR ratio
Rest	0.11±0.01	0.09±0.01	0.094	0.48±0.03*	0.47±0.03*	0.130
Peak exercise	0.20±0.02†	0.16±0.01†	0.037	0.59±0.04†*	0.53±0.03†*	0.019
PaO₂, mm Hg
Rest	102±7	85±6	0.078	71±6*	56±3*	0.001
Peak exercise	90±6	95±7	0.294	65±6*	56±3*	0.037
PaCO₂, mm Hg
Rest	36±2	37±1	0.541	33±1	33±1*	0.529
Peak exercise	37±1	33±2†	0.053	29±1†*	31±1†	0.020
ScvO₂,%
Rest	73±2	74±1	0.669	65±2*	62±2*	0.057
Peak exercise	43±6†	41±5†	0.201	38±3†	41±3†	0.083
C(a-cv)O₂, mL O₂/100 mL
Rest	4.8±0.4	4.4±0.2	0.169	6.3±0.4*	6.0±0.3*	0.434
Peak exercise	10.8±1.0†	11.3±0.9†	0.303	11.3±0.6†	10.2±0.6†	0.003

p Values from repeated measures ANOVA for difference between pre-sildenafil and post-sildenafil, and for rest vs peak exercise; †p<0.05 for difference vs rest; *p<0.05 for difference vs healthy control subjects by unpaired two-sample t test.
ANOVA, analysis of variance; C(a-cv)O₂, arterial-central venous oxygen content difference; CI, cardiac index; CTEPH, chronic thromboembolic pulmonary hypertension; mPAP, mean pulmonary arterial pressure; mSAP, mean systemic arterial pressure; PaCO₂, arterial carbon dioxide tension; PaO₂, arterial oxygen tension; RA, right atrial pressure; ScvO₂, central venous oxygen tension; SVi, indexed stroke volume; tPVR, total pulmonary vascular resistance; tSVR, total systemic vascular resistance.