. 2016 Apr 5;11(4):e0152987. doi: 10.1371/journal.pone.0152987

Table 2. Morphometric measurements and severity indices of intimal thickening in systemic and pulmonary arteries by groups.

Measurements	Systemic arteries
Measurements	COPD	Smokers	Non smokers	Overallp-value
Measured external diameter, μm	557 [485–668]	506 [440–599]	505 [427–632]	0.385
Measured total area, mm^-2x10^-3	239 [162–337]	199 [143–254]	189 [141–277]	0.338
Index of narrowing^a	0.27 [0.24–0.33]	0.30 [0.23–0.34]	0.28 [0.27–0.32]	0.845
Lumen area, mm^-2x10^-3	49.9 [25.9–69.6]	47.4 [24.5–59.2]	58.8 [20.1–92.2]	0.811
Intima area, mm^-2x10^-3	32.0 [19.6–57.0]	26.8 [17.7–37.7]	23.4 [17.5–37.1]	0.327
Muscular area, mm^-2x10^-3	157.2 [115.5–201.9]	117.1 [96.4–161.1]	113.3 [72.9–164.8]	0.169
Severity Indices^b
% intimal area	15.6 ± 1.5^†,^‡	14.2 ± 1.6	13.1 ± 1.8	0.022
% luminal narrowing	44.9 ± 4.2^†	40.2 ± 4.7	36.9 ± 5.3	0.030
Intimal thickness index	0.25 ± 0.03^†	0.24 ± 0.03	0.21 ± 0.03	0.091
Intima to media ratio	0.46 ± 0.04	0.46 ± 0.05	0.37 ± 0.05	0.678
	Pulmonary arteries
	COPD	Smokers	Non smokers	Overallp-value
N° of arteries measured by patient	10.2 ± 1.2	13.2 ± 1.8	8.7 ± 2.3	0.212
Measured external diameter, μm	294.2 [256.2–362.1]	323.9 [303.5–406.4]	327.5 [314.8–360.1]	0.176
Measured total area, mm^-2x10^-3	64.0 [49.8–99.1]	77.4 [64.2–121.6]	74.3 [65.8–84.7]	0.237
Index of narrowing^a	0.30 [0.28–0.32]	0.31 [0.28–0.32]	0.30 [0.29–0.34]	0.862
Lumen area, mm^-2x10^-3	18.0 [12.9–23.4]^‡	27.9 [25.3–37.3]	26.9 [16.9–35.4]	0.013
Intima area, mm^-2x10^-3	24.0 [18.2–32.7]	21.2 [16.4–33.3]	15.4 [12.2–21.1]	0.092
Muscular area, mm^-2x10^-3	21.8 [17.0–34.9]	27.5 [21.1–45.4]	30.3 [26.5–33.8]	0.291
Severity Indices^b
% intimal area	37.3 ± 2.2^†,^‡	29.3 ± 2.3	23.6 ± 2.8	0.002
% luminal narrowing	56.1 ± 3.1^†,^‡	43.4 ± 3.2	37.9 ± 4.1	0.003
Intimal thickness index	0.99 ± 0.06^†	0.82 ± 0.06	0.54 ± 0.08	<0.001
Intima to media ratio	1.17 ± 0.10^†	1.03 ± 0.11	0.80 ± 0.13	0.107

Data are presented as median [IQR] or LSM ± SEM. The reported p-value comes from the overall comparison with ANCOVA method with a general linear model using as covariables: gender, MetS, cHDL and circulating leukocytes.

Between-group comparisons were performed using the least significant difference method, where ^† means a p-value <0.05 for the difference between COPD and non-smokers group, and

^‡ means a p-value <0.05 for the difference between COPD and smokers group.

^aIndex of narrowing is estimated as the ratio between the measured total area and that extrapolated from the theoretical distended diameter: [theoretical diameter = length of the external elastic lamina / pi (π)].

^bThe severity indices were calculated using the following formulas: % intimal area = 100 X intimal area/measured total area (area encompassed by the external elastic lamina); % luminal narrowing = 100 X intimal area/internal elastic lamina area; Intimal thickness index = intimal area/medial area; and Intima to media ratio = width of intima at maximal intimal thickness/width of media at maximal intimal thickness.