Image-enhanced bronchoscopic evaluation of bronchial mucosal microvasculature in COPD

Figures & data

Figure 1 Bronchial wall thickness measurement in high-resolution CT scan.

Notes: Coronal (A) and axial (B) cuts demonstrated the identification of apical segmental bronchus of right upper lobe bronchus (RB1). (C) Shows axial cut of chest CT showing circumferential measures of outer and inner areas of RB1 to calculate airway cross-sectional area (PWA%). (D) Shows axial cut of chest CT measuring the inner and outer diameters to calculate I/O ratio and T/D ratio ([inner diameter − outer diameter/2] to outer bronchus diameter).
Abbreviations: CT, computed tomography; I/O ratio, inner to outer diameter ratio; SD, standard deviation; W, width; H; height; Min, minimum; Max, maximum; T/D ratio, bronchial wall thickness to outer diameter ratio.

Table 1 Baseline characteristics of the study population

Variable	COPD (n=29)	Controls (n=10)	Significant (P-value)
Age (years)	60 (53–65)	30.5 (20.8–52.3)	0.001*
Sex
Male/female; n (%)	21 (72.4)/8 (27.6)	5 (50)/5 (50)	0.250
Smoking history
Current/former/passive; n (%)	16 (55.2)/5 (17.2)/8 (27.6)	5 (50)/0 (0)/5 (50)	0.290
Pack/year index	57.5 (35–75)	30 (24–35)	0.047*
Spirometry
FEV1/FVC	55 (46–60)	82 (77.8–88.3)	0.001*
FEV1 (L)	1.4 (0.8–1.75)	2.75 (2.5–3.1)	0.002*
FEV1 % predicted	54 (35–65)	90 (72.5–106)	0.008*
GOLD stage
GOLD B/GOLD D	12 (41.4)/17 (58.6)	–	NA

Note:

* P≤0.05 is considered significant. Data expressed as median (IQR=25th–75th percentile) unless otherwise stated. “–” not relevant.

Abbreviations: FEV₁, forced expiratory volume 1; FVC, forced vital capacity; GOLD, Global initiative for chronic Obstructive Lung Disease; IQR, interquartile range; NA, not assessed.

Table 2 Clinical and functional characteristics of COPD according to GOLD scores

Variable	GOLD B (n=12; 41.4%)	GOLD D (n=17; 58.6%)	Significant P-value
Age (years)	62 (60–67.5)	58 (50.8–63.5)	0.2
Sex; n (%)
Male/female	10 (83.3)/2 (16.7)	11 (64.7)/6 (35.3)	0.6
Smoking history; n (%)
Current/former/passive	7 (58.3)/3 (25)/2 (16.7)	9 (53)/2 (11.7)/6 (35.3)	0.441
Pack year index	50 (33.8–70)	60 (28.8–80)	0.9
BMI (kg/m^2)	24.2 (20.4–27.4)	25.6 (23.98–28.7)	0.1
6MWT (m)	212.5 (200–220)	200 (180–216.3)	0.4
MMRC dyspnea scale	1 (1–1.5)	2 (1–2.25)	0.05
CAT score	12 (12–14)	14 (12–16)	0.19
COPD duration (years)	5 (3.5–10)	12 (5.75–20)	0.007*
AECOPD frequency/year	1 (1–1)	2 (2–2)	<0.001*
Comorbidities; n (%)	3 (27)	9 (50)	0.27
BODE index	3 (2.5–4)	5 (3–6.3)	0.04*
Spirometry
FEV1/FVC	60 (52.5–67.5)	48 (39–59)	0.005*
FEV1(L)	1.76 (1.58–1.98)	0.995 (0.75–1.4)	0.001*
FEV1%	62 (54.5–72.5)	40 (25.5–60)	,0.001*
FEF25–75%	53 (40.5–83.5)	16.5 (9.5–42)	0.01*
Chest CT scan
Bronchial wall thickness
PWA%	75 (74–78)	77 (76–80)	0.4
T/D ratio	0.26 (0.24–0.29)	0.26 (0.23–0.3)	0.9
I/O ratio	0.49 (0.4–0.51)	0.44 (0.39–0.5)	0.2
Emphysematous changes; n (%)	8 (66.7)	12 (70.6)
Emphysema visual score	1 (0.5–2)	1 (0.5–2)	0.8
Emphysema distribution; n (%)
Upper lobe	5 (57.1)	4 (38.5)
Upper + lower lobes	1 (14.3)	5 (38.5)	0.59
Lower lobe	2 (28.6)	3 (23.1)

Notes: PWA: airway cross-sectional area (PWA >63% indicated bronchial wall thickness¹³), T/D ratio: (inner diameter − outer diameter/2) to outer bronchus diameter (T/D ratio >0.22 indicated bronchial wall thickness¹⁴), I/O ratio <0.8 indicated bronchial wall thickness,¹³

* P≤0.05 is considered significant. Data expressed as median (IQR=25th–75th percentile) unless otherwise stated.

Abbreviations: GOLD, Global initiative for chronic Obstructive Lung Disease; BMI, body mass index; 6MWT, 6-minute walk test; CAT, COPD assessment test; AECOPD, acute exacerbation of COPD; FEV₁, forced expiratory volume after 1 second; FVC, forced vital capacity; FEF, forced expiratory flow; CT, computed tomography; I/O ratio, inner to outer diameter ratio; BODE, Body mass index, Airflow obstruction, Dyspnea, and Exercise capacity index; PWA, percentage of airway cross-sectional area; T/D ratio, bronchial wall thickness to outer diameter ratio; IQR, interquartile range; MMRC, modified Medical Research Council scale.

Figure 2 The different grades of endobronchial erythema identified by HD WLB (A–E) and i-scan3 (F, H–K).

Notes: A and F show decreased erythema (H–J); B and H show normal erythema (G0); C and I show mild erythema (G+1); D and J show moderate erythema (G+2); and E and K show severe erythema (G+3).

Abbreviations: HD WLB, high-definition white light bronchoscopy; G, grade of erythema.

Figure 3 HD WLB (A–C) and i-scan3 (D–F) showing various endobronchial mucosal changes.

Notes: A and D show mucosal striations (arrowheads), edema, and stoma; B and E show mucosal nodules (arrows); and C and F show mucosal thinning (stars).

Abbreviation: HD WLB, high-definition white light bronchoscopy.

Figure 4 Endobronchial mucosal microvasculature in COPD and controls.

Notes: (A) Distribution of CD34 among COPD patients and healthy controls; (B) a section through the bronchial lamina propria shows high microvascular density in a control subject (anti-CD34, ×400); (C) shows low microvascular density in a COPD patient as highlighted by CD34 endothelial immunostaining (anti-CD34, ×400); and (D) ROC curve to evaluate angiogenesis between COPD patients and healthy controls.
Abbreviation: ROC, receiver operating characteristic.

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