The Role of Lobe Selection on FEV₁ Response in Endobronchial Valve Therapy

Figures & data

Table 1. Baseline characteristics of the patients.

	Lower Lobe		Upper Lobe
	Control	Treatment	Control	Treatment
Subjects	41	82	110	237
Age, years	65.1(6.19)	65.2(7.14)	62.5(7.08)	62.7(7.80)^a
BMI	23.8(3.52)	23.7(4.04)	24.5(3.57)	24.6(4.00)
FEV1, L	0.86(0.26)	0.86(0.26)	0.89(0.29)	0.89(0.28)
FEF25-75	0.27(0.13)	0.28(0.10)	0.30(0.12)	0.29(0.13)
RV, L	5.23(1.30)	5.06(1.20)	4.62(1.10)	4.81(1.11)
TLC, L	8.00(1.51)	7.88(1.58)	7.46(1.40)	7.61(1.39)
RV/TLC	0.65(0.09)	0.64(0.09)	0.62(0.09)	0.63(0.09)
IC, L	1.74(0.52)	1.81(0.58)	1.76(0.62)	1.80(0.56)
DLCO, mL CO/min/mmHg	8.67(4.44)	8.56(4.10)	9.14(5.98)	8.57(3.58)
6MWT, m	357(114)	335(86.3)	353(93.0)	337(97.5)
mMRC	1.86(0.99)	1.92(1.04)	1.80(0.84)	1.91(0.94)
SGRQ	55.6(13.7)	54.6(14.2)	51.9(15.6)	54.3(13.6)
Cycle ergometry, W	47.4(24.5)	45.3(21.6)	47.8(22.6)	47.4(23.3)
BODE	4.44(1.35)	4.34(1.78)	4.32(1.31)	4.79(1.63) ^b

Characteristics of control and treatment patients at baseline. Data is presented as a mean with standard deviation in parenthesis. P values (not shown) were calculated using Student's two sample t-test. BMI: body mass index; FEV₁: forced expiratory volume in 1 second; FEF_25-75: mean forced expiratory flow between 25% and 25% FVC; RV: residual volume, TLC: total lung capacity; IC: inspiratory capacity; DLCO: carbon monoxide diffusion capacity; 6MWT: 6 minute walk test; mMRC: modified Medical Research Council Dyspnea Score; SGRQ: St. George's Respiratory Questionnaire; BODE: BMI, airflow obstruction, dyspnea and exercise capacity.

^aStatistically significant difference between treatment groups (p < 0.05)

^bStatistically significant difference between upper lobe control and treatment (p < 0.05).

Figure 1. Study flow chart. All 470 patients had initial FEV₁ measurements. The patients were divided into two groups, upper and lower lobe, based on treatment lobe. Total patients at baseline and at 365 days by group are represented. EBV: Endobronchial Valve.

Table 2. Mean percent change of primary outcomes at 365 days.

(A) All Patients
	Lower Lobe			Upper Lobe
	Control	Treatment	p value	Control	Treatment	p value	p value between treatment groups
Patients	33	65		90	196
FEV1, L	–0.57 (± 19.6)	5.99 (± 17.6)	0.10	–2.15 (± 13.4)	7.04 (± 25.0)	0.001	0.75
6MWT	–8.06 (± 23.9)	1.86 (± 29.7)	0.11	1.94 (± 28.4)	2.73 (± 28.5)	0.83	0.84
(B)Patients with Complete Fissure
	Lower Lobe			Upper Lobe
	Control	Treatment	p value	Control	Treatment	p value	p value between treatment groups
Patients	14	34		37	70
FEV1, L	1.71 (± 24.3)	12.2 (± 16.2)	0.09	–2.83 (± 9.20)	17.6 (± 28.6)	<0.001	0.31
6MWT	–1.38 (± 23.3)	1.55 (± 28.8)	0.75	4.25 (± 30.7)	7.46 (± 25.70	0.57	0.07

Results are expressed as mean percent change at 365 days. P values calculated using Student's two sample t-test. Standard deviations are expressed in (). (A) All patients. (B) Patients with pre-treatment complete fissure occlusion (90% or greater integrity by CT scan). FEV₁: forced expiratory volume in 1 second; 6MWT: 6-minute walk test.

Figure 2. The mean percent decrease in target lobe volume between treatment group and control group is shown. Data is separated by target lobe. Results were quantified by volumetric CT scan at 180 days. Standard deviation is represented in the error bars.

Table 3. Baseline Predictors of Change in FEV₁.

Multiple Regression Analysis vs.% Change in FEV1
Variable	p Value
Fissure Integrity	0.0009
Emphysema Heterogeneity	0.23
Target Lobe	0.28

Correlates of change in FEV₁. Linear Regression Analysis was performed with 95% confidence intervals. A statistically significant correlation was seen between both fissure integrity and FEV₁ improvement.

Figure 3. Odds Ratio calculations at 365 days are expressed. The following cut-offs were used to evaluate significance: FEV₁ > 15%, Fissure integrity > 90% and Heterogeneity > 15%. A positive correlation between the presence of complete fissure (>90% on CT) and improvement in FEV₁ was seen.