Chronic thromboembolic pulmonary hypertension is associated with a loss of total lung volume on computed tomography

Table 1 Population characteristics

Characteristic	CTEPH, n = 15		Control, n = 45	P value
Age in yr, mean (95%CI)	48 (40, 83)		48 (40, 83)	-
Height in cm, mean (95%CI)	159 (151, 162)		159 (154, 163)	0.5
Weight in kg, mean (95%CI)	58 (49, 75)		61 (54, 72)	0.9
Interval between initial and follow-up CT in d, mean (95%CI)	547 (273, 846)		531 (294, 815)	0.9
Results of RHC and echocardiography	Initial, n = 15	Follow-up, n = 15		P value
Pulmonary arterial pressure in mmHg, mean (95%CI)	47 (38, 59)	34 (23, 44)	-	0.001b
Cardiac output in L/min, mean (95%CI)	3.4 (2.8, 4.3)	4.6 (3.6, 6.1)	-	0.01a
Cardiac index in L/min/m2, mean (95%CI)	2.2 (1.6, 2.7)	2.7 (2.4, 3.6)	-	0.01a
Tricuspid regurgitation pressure gradient in mmHg, mean (95%CI)	66 (51, 77)	42 (23, 61)	-	0.01a
Left ventricular end-diastolic diameter in mm, mean (95%CI)	38 (37, 42)	44 (41, 47)	-	0.02a
Left ventricular end-systolic diameter in mm, mean (95%CI)	25 (22, 28)	27 (24, 31)	-	0.5
Results of spirometry	Initial, n = 10	Follow-up, n = 10
Vital capacity % predicted	83 (70, 102)	87 (76, 99)	-	0.2
Forced vital capacity % predicted	76 (71, 97)	83 (74, 97)	-	0.3
Forced expiratory volume-one second % predicted	74 (63, 959	83 (69, 96)	-	0.5

^aP < 0.05.

^bP < 0.01. CI: Confidence interval; CT: Computed tomography; CTEPH: Chronic thromboembolic pulmonary hypertension; RHC: Right heart catheterization.

Table 2 Comparison between measurements on initial and follow-up computed tomography

CT measurement	CTEPH, n = 15			Control, n = 45
	Initial	Follow-up	P value	Initial	Follow-up	P value
Total lung volume in mL, mean (95%CI)	3238 (3016, 4494)	3360 (2687, 4043)	0.004b	3669 (3063, 4167)	3657 (2993, 4385)	0.9
Right lung volume in mL, mean (95%CI)	1879 (1700, 2619)	1817 (1522, 2299)	0.003b	1939 (1635, 2268)	1990 (1614, 2347)	0.9
Right upper + middle lobe volume in mL, mean (95%CI)	977 (913, 1103)	973 (900, 1148)	0.2	1028 (868, 1169)	1010 (865, 1212)	1.0
Right lower lobe lung volume in mL, mean (95%CI)	978 (737, 1123)	815 (611, 1111)	0.01a	931 (707, 1112)	911 (733, 1148)	0.8
Left lung volume in mL, mean (95%CI)	1396 (1316, 1875)	1455 (1216, 1744)	0.1	1692 (1376, 1940)	1659 (1403, 2023)	0.7
Left upper lobe lung volume in mL, mean (95%CI)	836 (752, 925)	802 (689, 1000)	0.4	867 (747, 1042)	869 (741, 1089)	0.9
Left lower lobe lung volume in mL, mean (95%CI)	636 (555, 902)	652 (476, 806)	0.05	826 (628, 939)	749 (622, 999)	0.6
Heart cross-sectional area in cm2, mean (95%CI)	97 (86, 112)	83 (69, 100)	0.001b	75 (65, 85)	74 (64, 85)	0.7

^aP < 0.05.

^bP < 0.01. CI: Confidence interval; CT: Computed tomography; CTEPH: Chronic thromboembolic pulmonary hypertension.

Table 3 Lung volume and heart-size change in patients with chronic thromboembolic pulmonary hypertension and in the control group

Parameter	CTEPH, n = 15	Control, n = 45	P value
Total lung volume change in mL, mean (95%CI)	176 (13, 468)	39 (-228, 252)	0.01a
Right lung volume change in mL, mean (95%CI)	120 (47, 292)	4 (-121, 126)	0.007b
Right upper + middle lobe lung volume change in mL, mean (95%CI)	35 (-26, 91)	-7 (-46, 46)	0.9
Right lower lobe lung volume change in mL, mean (95%CI)	85 (19, 167)	-9 (-66, 83)	0.01a
Left lung volume change in mL, mean (95%CI)	23 (-37, 214)	33 (-109, 99)	0.1
Left upper lobe lung volume change in mL, mean (95%CI)	13 (-31, 81)	1 (-44, 53)	0.4
Left lower lobe lung volume change in mL, mean (95%CI)	40 (-23, 112)	9 (-59, 63)	0.1
Cardiac cross-sectional area change in cm2, mean (95%CI)	19 (4, 25)	-0.3 (-2, 3)	0.0002c

^aP < 0.05.

^bP < 0.01.

^cP < 0.001. CI: Confidence interval; CTEPH: Chronic thromboembolic pulmonary hypertension.