Pulmonary Artery Abnormalities in Ex-smokers with and without Airflow Obstruction

Figures & data

Figure 1.  Pulmonary artery volume measurements from thoracic CT. Left panel shows axial view of CT volume. The axes of segmentation are defined from the bifurcation parallel to each of the main, left and right pulmonary arteries at the level of the bifurcation. Middle panel shows a representative slice of the segmented artery. Right panel shows the segmented main (in red), left (in blue) and right (in green) pulmonary arteries. Scale bar = 1 cm.

Table 1.  Subject characteristics

	Never-Smokers (n = 35)	Ex-smokers FEV1/FVC ≥ 70% (n = 56)	Ex-smokers FEV1/FVC < 70% (n = 68)	Sig. Diff. All Ex-smokers p	Sig. Diff. All Groups p
Age yrs	71 (7)	69 (10)	71 (9)	.35	.29
Male n (%)	17 (49)	33 (59)	48 (71)	-	-
BMI kg/m^2	26 (3)	29 (4)	27 (4)	<.001	<.001
Pack-years	–	28 (17)	47 (29)	<.001	<.001
FEV1%pred	107 (18)	98 (17)	63 (23)	<.001	<.001
FEV1/FVC %	77 (6)	80 (6)	50 (13)	<.001	<.001
FRC %pred	104 (22)	95 (19)	139 (36)	<.001	<.001
TLC %pred	100 (14)	101 (12)	118 (18)	<.001	<.001
DLCO %pred	91 (16)	79 (20)	54 (19)	<.001	<.001
SGRQ	–	25 (21)	40 (17)	<.001	<.001
6MWD m	–	401 (96)	369 (90)	.06	.06
^3He MRI VDP %	3 (2)	6 (3)	18 (10)	<.001	<.001
^3He MRI ADC cm^2/s	0.29 (0.03)	0.28 (0.04)	0.42 (0.11)	<.001	<.001
CT RA950%	1 (1)	1 (1)	11 (11)	<.001	<.001
WA%	66.6 (2.2)	65.0 (2.2)	65.2 (1.9)	.016	.001
Airway count	132 (40)	109 (38)	78 (29)	<.001	<.001
Main PA Volume cm^3	21 (4)	24 (3)	25 (4)	.014	<.001
Left PA Volume cm^3	8 (1)	9 (1)	10 (1)	.09	<.001
Right PA Volume cm^3	8 (1)	9 (1)	10 (2)	.001	<.001
Total PA Volume cm^3	28 (4)	31 (3)	33 (5)	.003	<.001

BMI = Body Mass Index; FEV₁ = Forced Expiratory Volume in 1 Second; %pred = Percent Predicted; FVC = Forced Vital Capacity; FRC = Functional Residual Capacity; TLC = Total Lung Capacity; DL_CO = Diffusing Capacity for Carbon Monoxide; SGRQ = St. George's Respiratory Questionnaire; 6MWD = Six-Minute Walk Distance; VDP = Ventilation Defect Percent; ADC = Apparent Diffusion Coefficient; RA₉₅₀ = CT attenuation values below −950 HU; WA% = Wall Area Percent of 5^th generation airways; PA = Pulmonary Artery; SD = Standard Deviation; Sig. Diff. = significant difference between the three groups, ex-smokers with and without airflow obstruction and never-smokers. Main, left, right and total PA volumes adjusted for body surface area and age. Bold values denote statistical significance.

Figure 2.  Representative MRI and CT pulmonary and pulmonary artery disease biomarkers. Subject 1: 74-year-old female never-smoker FEV₁/FVC = 72%, FEV₁%_pred = 90%, VDP = 1%, ADC = 0.27 cm²/s, WA% = 69%, main pulmonary artery volume = 18 cm³, left pulmonary artery volume = 7 cm³, right pulmonary artery volume = 7 cm³, total pulmonary artery volume = 26 cm³. Subject 2: 67-year-old male ex-smoker FEV₁/FVC = 94%, FEV₁%_pred = 103%, VDP = 5%, ADC = 0.30 cm²/s, WA% = 56%, main pulmonary artery volume = 24 cm³, left pulmonary artery volume = 9 cm³, right pulmonary artery volume = 9 cm³, total pulmonary artery volume = 31 cm³. Subject 3: 62-year-old female ex-smoker FEV₁/FVC = 76%, FEV₁%_pred = 64%, VDP = 13%, ADC = 0.23 cm²/s, WA% = 68%, main pulmonary artery volume = 23 cm³, left pulmonary artery volume = 9 cm³, right pulmonary artery volume = 8 cm³, total pulmonary artery volume = 30 cm³. Subject 4: 76-year-old male ex-smoker GOLD grade II COPD, FEV₁/FVC = 39%, FEV₁%_pred = 56%, VDP = 24%, ADC = 0.50 cm²/s, WA% = 66%, main pulmonary artery volume = 29 cm³, left pulmonary artery volume = 11 cm³, right pulmonary artery volume = 11 cm³, total pulmonary artery volume = 38 cm³. Subject 5: 86-year-old male ex-smoker GOLD grade III COPD, FEV₁/FVC = 35%, FEV₁%_pred = 38%, VDP = 30%, ADC = 0.48 cm²/s, WA% = 67%, main pulmonary artery volume = 30 cm³, left pulmonary artery volume = 11 cm³, right pulmonary artery volume = 12 cm³, total pulmonary artery volume = 40 cm³.

Figure 3.  Pulmonary artery volumes for ex- and never-smokers. Post-hoc analysis showed significant differences between ex-smokers and never-smokers for all PA volumes. Significant differences in pulmonary artery volume were also observed between ex-smokers with and without airflow obstruction except for the left pulmonary artery.

Table 2.  Pearson correlations for pulmonary artery volumes

Parameter	MPAV r (p)	LPAV r (p)	RPAV r (p)	TPAV r (p)
All Subjects (n = 159)
FEV1/FVC %	−0.26 (.004)	−0.23 (.02)	−0.30 (.001)	−0.28 (.002)
FEV1%pred	−0.24 (.009)	−0.22 (.03)	−0.23 (.008)	−0.21 (.01)
DLCO %pred	−0.22 (.02)	−0.21 (.03)	−0.26 (.004)	−0.24 (.009)
Airway count	−0.31(<.001)	−0.28 (.002)	−0.27 (.003)	−0.26 (.004)
RA950%	0.14 (NS)	0.15 (NS)	0.17 (.03)	0.16 (.04)
VDP %	0.37(<.001)	0.35 (<.001)	0.38 (< .001)	0.37 (< .001)
ADC cm^2/s	0.21 (.016)	0.20 (.02)	0.24 (.006)	0.23 (.01)
All Ex-smokers (n = 124)
FEV1/FVC %	−0.14 (NS)	−0.09 (NS)	−0.19 (NS)	−0.17 (NS)
FEV1%pred	−0.02 (NS)	0.003 (NS)	−0.05 (NS)	−0.04 (NS)
DLCO %pred	−0.06 (NS)	−0.01 (NS)	−0.13 (NS)	−0.11 (NS)
Airway count	−0.09 (NS)	−0.08 (NS)	−0.10 (NS)	−0.09 (NS)
RA950%	0.03 (NS)	0.03(NS)	0.08 (NS)	0.07 (NS)
VDP %	0.23 (NS)	0.20 (NS)	0.27 (.02)	0.25 (.03)
ADC cm^2/s	0.11 (NS)	0.08(NS)	0.16 (NS)	0.14 (NS)
Never-Smokers (n = 35)
FEV1/FVC %	−0.36 (NS)	−0.40 (NS)	−0.39 (NS)	−0.39 (NS)
FEV1%pred	−0.37 (NS)	−0.25 (NS)	−0.27 (NS)	−0.27 (NS)
DLCO %pred	0.06 (NS)	−0.05 (NS)	−0.03 (NS)	−0.03 (NS)
Airway count	−0.38 (NS)	−0.24 (NS)	−0.26 (NS)	−0.27 (NS)
RA950%	−0.12 (NS)	0.00 (NS)	−0.02 (NS)	−0.03 (NS)
VDP %	0.45 (NS)	0.45 (.04)	0.46 (.04)	0.46 (.04)
ADC cm^2/s	0.28 (NS)	0.35 (NS)	0.34 (NS)	0.34 (NS)

FEV₁ = Forced Expiratory Volume in 1 Second; DL_CO = Diffusing Capacity for Carbon Monoxide; RA₉₅₀ = CT attenuation < −950 HU; VDP = Ventilation Defect Percent; ADC = Apparent Diffusion Coefficient; MPAV = Main Pulmonary Artery Volume; LPAV = Left Pulmonary Artery Volume; RPAV = Right Pulmonary Artery Volume; TPAV = Total Pulmonary Artery Volume; NS = Statistically not significant. Bold values denote statistical significance.

Table 3.  Relationships with total exacerbations in COPD patients (n = 68)

	Relationships With Total Exacerbations (2.5 yrs prior to 2.5 yrs post-visit)
	Univariate	Multivariate Model
Parameter	r (p)	Fold Change	p
Age yrs	0.15 (.23)	–	–
BSA m^2	−0.07 (.58)	–	–
Previous Exacerbations (5 to 2.5yrs prior visit)	0.64 (<.001)	1.75	.08
FEV1%pred	−0.38 (.002)	−2.88	.004
DLCO %pred	−0.26 (.034)	2.12	.03
RV/TLC %pred	0.31 (.011)	−0.87	.38
SGRQ Score	0.36 (.003)	−0.05	.96
6MWD m	−0.36 (.003)	−2.08	.04
CT RA950%	0.19 (.12)	–	–
WA%	0.10 (.42)	–	–
Airway Count	−0.36 (.002)	−1.26	.21
^3He MRI VDP %	0.32 (.008)	0.73	.46
^3He MRI ADC cm^2/s	0.14 (.25)	–	–
PA/A diameter	0.11 (.37)	–	–
Main PA Volume cm^3	0.22 (.07)	–	–
Left PA Volume cm^3	0.33 (.005)	−0.24	.81
Right PA Volume cm^3	0.24 (.051)	–	–
Total PA Volume cm^3	0.25 (.037)	2.12	.03

BSA= Body Surface Area; FEV₁ = Forced Expiratory Volume in 1 Second; DL_CO = Diffusing Capacity for Carbon Monoxide; RV = Residual Volume; TLC = Total Lung Capacity; SGRQ = St. George's Respiratory Questionnaire; 6MWD = Six-Minute Walk Distance; RA₉₅₀ = CT attenuation values below −950 HU; WA% = Wall Area Percent of 5^th generation airways; VDP = Ventilation Defect Percent; ADC = Apparent Diffusion Coefficient; PA = Pulmonary Artery, A = Aorta. Bold values denote statistical significance.