Predicting Respiratory Complications Following Lobectomy Using Quantitative CT Measures of Emphysema

Figures & data

Figure 1 Representation of a 3-dimensional lung model. Low attenuation area (LAA) is shown in red. The percentage LAA (LAA%) is calculated as: LAA% = volume of LAA/total lung volume × 100.

Table 1 Patient Characteristics (n = 343)

Background Factors		Value
Sex	Male	143 (41.8)
	Female	199 (58.2)
Age, years		68 ± 9.5
Smoking index		495 ± 675
BMI, kg/m^2		23.1 ± 3.4
PFT, %	FEV1.0%	73.6 ± 9.4
	%FVC	111.4 ± 17.9
	%DLCO	97.8 ± 25.0
Whole tumour size, mm		25.5 ± 14.0
Histology	Adenocarcinoma	272 (79.5)
	Squamous cell carcinoma	53 (15.5)
	Others	17 (5.0)
Resected lobes	Upper	195 (57.0)
	Middle	23 (6.7)
	Lower	124 (36.3)
LAA%		7.0 ± 7.4
PRC		50 (14.6)

Note: Values are presented as n (%) or mean ± standard deviations unless otherwise indicated.

Abbreviations: BMI, body mass index; PFT, pulmonary function test; FVC, forced vital capacity; FEV₁, forced expiratory volume in 1 s; DLCO, diffusing capacity of the lungs for carbon monoxide; LAA, low attenuation area; PRC, postoperative respiratory complications.

Figure 2 Box plot comparing the percentage of low attenuation area (LAA%) between patients with and without postoperative respiratory complications (PRC).

Table 2 Postoperative Respiratory Complications in High and Low LAA% Groups

	Low (LAA% <10%) (n = 262)	High (LAA% ≥10%) (n = 80)	P value
Pneumonia	2 (0.8)	4 (5.0)	0.029
Atelectasis	6 (2.3)	2 (2.5)	1
Prolonged air leakage	7 (2.7)	6 (7.5)	0.086
Empyema	2 (0.8)	2 (2.5)	0.234
Hypoxia	1 (0.4)	4 (5.0)	0.012
Ischemic bronchitis	2 (0.8)	1 (1.3)	0.552
Bronchopleural fistula	1 (0.4)	0 (0)	0.580
IP exacerbation	3 (1.1)	1 (1.3)	0.939
Others	6 (2.3)	0 (0)	0.342
Total	30 (11.5)	20 (25.0)	0.035

Note: Values are n (%) or n.

Abbreviations: LAA, low attenuation area; IP, interstitial pneumonia.

Table 3 Uni- and Multivariable Analysis of Clinical Factors for Predicting PRC

	Univariable Analysis		Multivariable Analysis
	OR (95% CI)	P value	OR (95% CI)	P value
Male sex	4.446 (2.294–8.616)	<0.001	4.876 (2.294–8.616)	<0.001
Age	2.438 (1.289–4.609)	0.006	–	–
BMI	0.623 (0.326–1.191)	0.153	–	–
Smoking index	4.357 (2.147–8.843)	<0.001	–	–
Whole tumour size	1.308 (0.710–2.408)	0.389	–	–
Histology	3.227 (1.697–6.135)	<0.001	–	–
FEV1.0%	1.978 (1.071–3.654)	0.029	–	–
%FVC	1.031 (0.528–2.011)	0.930	–	–
%DLCO	3.081 (1.252–7.585)	0.014	0.975 (0.960–0.991)	0.002
LAA%	4.239 (2.089–8.601)	<0.001	1.040 (1.001–1.080)	0.046

Abbreviations: PRC, postoperative respiratory complications; OR, odds ratio; CI, confidence interval; BMI, body mass index; PFT, FVC, forced vital capacity; FEV₁, forced expiratory volume in 1 s; DLCO, diffusing capacity of the lungs for carbon monoxide; LAA, low attenuation area.

Figure 3 Scatter plot showing the relationship between FEV_1.0% and percentage of low attenuation area (LAA%). The r value indicates the Pearson correlation coefficient.

Figure 4 Receiver operating characteristic curve of the low attenuation area (LAA%) for postoperative respiratory complications (PRC).

Abbreviation: AUC, area under the curve.