Results of one way bronchial valve placement in treatment of emphysema

Objectives: To evaluate the results of one-way valve placement in treatment severe emphysema in chronic obstructive pulmonary disease. Subjects and methods: This study was a prospective, randomized clinical trial and carried out on 33 stable chronic obstructive pulmonary disease (COPD) patients with localized advanced emphysema.

Journal of military pharmaco-medicine No7-2017 RESULTS OF ONE-WAY BRONCHIAL VALVE PLACEMENT IN TREATMENT OF EMPHYSEMA Dao Ngoc Bang*; Dong Khac Hung**; Ta Ba Thang*; Nguyen Quang Binh*** SUMMARY Objectives: To evaluate the results of one-way valve placement in treatment severe emphysema in chronic obstructive pulmonary disease Subjects and methods: This study was a prospective, randomized clinical trial and carried out on 33 stable chronic obstructive pulmonary disease (COPD) patients with localized advanced emphysema Patients underwent clinical examination, chest computed tomography (CT), measurement of FEV1, RV, TLC and Raw and arterial blood gases before and at the 3rd month after therapy The one-way bronchial valve Zephyr was placed in lobar or segmental bronchi via flexible bronchoscopy Results: 31 patients were placed one valve, following by one patient with two valves and one patient with valves 27 valves with the size of 5.5 mm were used The results were seen at the 3rd month after therapy that the 6-minute walk distance (6-MWD) increased in 48.48% of patients more than 26 meters; CAT index decreased in 75.76% of patients more than points The increase of 6-MWD and decrease of CAT and mMRC were significant in comparison with baseline and control group (p < 0.05) FEV1 improved more than 10% predicted in 9.09% of patients To compare with the baseline and control group, the increase of FVC and decrease of RV and TLC were significant (p < 0.05) Complications and adverse events were seen after valve insertion rarely and lightly Conclusions: One-way valve has the efficacy to reduce lung volume in treatment of COPD patients with severe emphysema The technique was safe * Keywords: Chronic obstructive pulmonary disease; Emphysema; One-way bronchial valve INTRODUCTIONS Emphysema is the constant progressive unrecovered hyperinflammation of air space under the bronchiales and the destruction of alveoli’s wall without fibrosis It causes limitation of airflow and decrease of lung elastic recoil, leading to the frequent progressive status of dyspnoe, limitation of physical activities and decrease of life’s quality Nowadays, the esults of emphysema treatment by internal medicine are unremarkable Lung volume reduction has proved as a prospect for COPD patients with severe emphysema by its efficacies, such as: decrease of dyspnea status, improvement of lung function and the quality of life, increase of physical activities and reduction of frequency of exacerbation in COPD patients [4] The early results of bronchoscopic lung volume reduction with * 103 Military Hospital ** Vietnam Military medical University *** National Hospital of Odontostomatology Corresponding author: Dao Ngoc Bang (bsdaongocbang@yahoo.com.vn) Date received: 15/06/2017 Date accepted: 07/08/2017 78 Journal of military pharmaco-medicine no7-2017 one-way valve were seen in patients with severe emphysema This technique intervenes less than surgery, leading to the minimal light complications and adverse events [3] In Vietnam, this technique has been done firstly in the 103 Military Hospital from 2014 The purpose of this study: To evaluate the results of one-way valve placement in treatment of severe emphysema in chronic obstructive pulmonary disease SUBJECTS AND METHODS Subjects 66 patients were diagnosed as stable COPD with severe emphysema, treated in the Tuberculosis and Lung Diseases Department, 103 Hospital from January 2014 to May 2017 Patients were divided into groups: - Treatment group (group I): 33 patients with severe emphysema and stable COPD underwent one-way valve placement and optimal medical therapy - Control group (group II): 33 patients with severe emphysema and stable COPD underwent only optimal medical therapy Diagnosis of stable COPD based on GOLD standards (2013) The severity of emphysema was determined by chest computed tomography (CT) and measurment of residual volume (RV) Patient selection based on the standards of the Guidelines for Internal Respiratory Techniques of the Vietnam Ministry of Health (2014): severe obstructive airway (20% pred < FEV1 < 50% pred.); TLC ≥ 100% pred., RV ≥ 150% pred After bronchodilator inhalation and before respiratory function recovery; advanced predominant emphysema in one lobe on High-Resolution Computed Tomography (HRCT), giving up smoking more than months, no collateral ventilation below the location of valve [6] Exclusion criteria were patients who had contraindications of plethysmography measument and flexible bronchoscopy [4] Methods This study was a prospective, randomized clinical trial to compare two methods of treatment for patients with advanced emphysema, including LVR valve combined optimal medical therapy and optimal medical therapy alone Patients underwent clinical examination, blood testes, ECG, echocardiography, standard chest X-ray, chest CT, spirometry, plethysmography and arterial blood gases test before therapy Patients in treatment group underwent flexiable bronchoscopy (Fujinon, Japan) with the chanel for instrumention of 2.8 mm to control the status of bronchial tree, determine the lobal or segmental bronchi needed to place valve and clean the airway Collateral ventilation was controlled by Chartis system (PulmonX, USA) The diameter of bronchi was measured by catheter in order to select one-way Zephyr valve (PulmonX, USA) with suitable sizes Valve was inserted into the catheter, delivered via the instrumental chanel of bronchoscope to target bronchi and placed to occlude segmental or lobal bronchi leading to the target lobe After that, the activity of valve was controlled 79 Journal of military pharmaco-medicine No7-2017 At the end of therapy, patients went back to their room and were followed and treated complications and adverse events of the technique All patients were treated by optimal medical therapy for stable COPD followed guidelines of GOLD (2013) They were examined again after and months By every time, they were estimated clinical status (degree of dyspnoe based on modified Medical Research Coucil-mMRC, COPD Assessment test-CAT index, body mas index (BMI) and 6-minute walk distance (6-MWD), indexes of respiratory function such as vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in one second (FEV1), residual volume (RV), total lung capacity (TLC) and airway resistance (Raw) Evaluating early complications (within week after therapy) and later adverse events (in to months after therapy) Data was recorded and analysed in the software SPSS 20.0 RESULTS Characteristics of patients Table 1: Clinical characteristics of groups Indexes Age ( X ± SD) (years) Male Smoking ( X ± SD) (pack/year) Duration of disease ( X ± SD) (years) BMI ( X ± SD) (kg/m²) CAT ( X ± SD) mMRC ( X ± SD) 6-MWD ( X ± SD) (m) Group I Group II (n = 33) (n = 33) 65.70 ± 7.32 65.91 ± 6.69 > 0.05 33 (100%) 33 (100%) > 0.05 29.68 ± 11.73 23.49 ± 11.32 < 0.05 7.83 ± 3.58 7.38 ± 5.68 > 0.05 18.61 ± 2.44 17.90 ± 2.47 > 0.05 20.12 ± 3.43 18.64 ± 2.95 > 0.05 2.52 ± 0.80 2.24 ± 0.87 > 0.05 302.00 ± 59.53 303.64 ± 60.03 > 0.05 p The patients in groups had high mean of age with long duration of disease, low BMI and high CAT score The ability of physical activity decreased, with the short 6-MWD (302.00 ± 59.53 meters in treatment group and 303.64 ± 60.03 meters in controlled group) There was no difference between groups in the average age, BMI, CAT and 6-MWD However, the patients in the group I smoked more than ones in the group II 80 Journal of military pharmaco-medicine no7-2017 Table 2: Respiratory function characteristics of groups before technique Indexes Group I (n = 33) Group II (n = 33) p 76.09 ± 21.26 73.27 ± 13.05 > 0.05 60.18 ± 15.92 68.18 ± 12.76 < 0.05 34.67 ± 15.02 35.36 ± 11.35 > 0.05 32.39 ± 12.50 29.36 ± 11.99 > 0.05 250.27 ± 73.88 253.73 ± 72.83 > 0.05 138.12 ± 24.01 143.21 ± 28.31 > 0.05 9.04 ± 4.31 9.52 ± 4.02 > 0.05 72.21 ± 7.66 78.52 ± 14.83 < 0.05 43.73 ± 4.56 43.39 ± 9.58 > 0.05 Respiratory function indexes VC ( X ± SD) (%Pred) FVC ( X ± SD) (%Pred) FEV1 ( X ± SD) (%Pred) MVV ( X ± SD) (%Pred) RV ( X ± SD) ((%Pred) TLC ( X ± SD) ((%Pred) Raw ( X ± SD) (cm H20/l/sec) Arterial blood gases PaO2 ( X ± SD) (mmHg) PaCO2 ( X ± SD) (mmHg) The mean of VC, FEV1, FVC and PaO2 decreased and the opposite was seen in RV, TLC, Raw and PaCO2 in the both groups of patients Mean of FEV1 in both groups belonged to the COPD stage III of GOLD 2013 RV and TLC increased so much, corresponding to severe emphysema Mean of Raw was so high in the both groups PaO2 decreased quite much and PaCO2 had the trend to go up, but mean of PaCO2 still belonged to the normal limitation There was no difference in FEV1, VC, RV, TLC and Raw between groups (p > 0.05) However, the means of FVC and PaO2 of patients in the group II were significant higher than ones in the group I (p < 0.05) Figure 1: Position of severe emphysema on CT-scan images In this study, severe emphysema located most in the lower lobe, with the portion of 60.61% in the group I and 96.97% in group II The rate of severe emphysema located in the upper lobe in the group I was significant higher than it in the group II No patient in the group II had severe emphysema in the middle lobe 81 Journal of military pharmaco-medicine No7-2017 Quantity and position of bronchial valves Table 3: Indexes n % 4.0 mm 25.00 5.5 mm 27 75.00 Total of valves 36 100 valve 31 94.94 valves 3.03 valves 3.03 Total of patients 33 100 Right upper lobe 22.22 Right middle lobe 11.11 Right lower lobe 20 55.55 Left upper lobe 5.56 Left lower lobe 5.56 Total of valves 36 100 Size Quantity of valve per patient Position of valves The rate of valve with the size 5.5 mm used was 75.00% 31 patients were treated with only one (94.94%), patient (3.03%) with two and patient (3.03%) with three valves The portion of valve located in the right lung was 88.88%, in which the most was seen in the right lower lobe (55.55%) Only valves (11.12%) were located in the left lung Results of bronchoscopy lung volume reduction with one-way bronchial valve in treatment of emphysema Table 4: Changes of clinical characters of patients in groups after months Index Group I Before technique (1) (n = 33) Group II months later (2) (n = 33) Before treatment (3) (n = 23) p months later (4) (n = 23) BMI (kg/m²) X ± SD Change 82 18.61 ± 2.44 18.58 ± 2.55 -0.03 ± 0.38 17.61 ± 2.70 17.58 ± 2.70 -0.03 ± 0.10 p2,1 > 0.05 p2,4 > 0.05 p4,3 > 0.05 > 0.05 Journal of military pharmaco-medicine no7-2017 CAT (points) X ± SD Change Decrease ≥ points (n) (%) 17.79 ± 3.39 20.12 ± 3.42 18.78 ± 3.10 -2.33 ± 1.27 25 (75.76) 17.65 ± 3.71 -1.13 ± 1.36 11 (47.82) p2,1 < 0.01 p2,4 > 0.05 p4,3 < 0.01 < 0.05 < 0.05 6-MWD (m) X ± SD 333.48 ± 62.69 302.00 ± 59.53 326.74 ± 88.72 307.39 ± 67.89 p2,1 < 0.01 p2,4 > 0.05 p4,3 < 0.05 Change 31.48 ± 26.30 19.35 ± 36.03 > 0.05 Increase ≥ 26 m (n) (%) 16 (48.48) (21.74) < 0.05 mMRC (points) X ± SD Change 2.03 ± 1.05 2.52 ± 0.80 -0.48 ± 0.57 2.26 ± 0.92 2.09 ± 0.79 -0.17 ± 0.49 p2,1 < 0.01 p2,4 > 0.05 p4,3 < 0.01 < 0.05 After month therapy, BMI of patients in the both groups changed insignificantly The patients in the group I witnessed the significant increase of 6-MWD (p < 0.01), with 16 patients (48.48%) more than 26 meters Most of patients in the group I decreased CAT index significantly (p < 0.01), with the improvement more than points in 75.76% of patients The similar trend was seen in the decrease of mMRC in group I (p < 0.01) In comparison with the group II, the group I had the significant improvement of 6-MWD, CAT and mMRC (p < 0.05) Table 5: Changes of respiratory function indexes of patients in groups after months Group I Indexes Before technique (1) (n = 33) Group II months later (2) (n = 33) Before treatment (3) (n = 23) months later (4) (n = 23) 76.22 ± 13.39 75.78 ± 17.47 p VC (%pred) X ± SD Change 76.09 ± 21.26 73.97 ± 25.02 - 2.12 ± 24.11 -0.43 ± 20.31 p2,1 > 0.05 p2,4 > 0.05 p4,3 > 0.05 < 0.05 FVC (%pred.) X ± SD Change 60.18 ± 15.92 67.42 ± 23.98 7.24 ± 18.81 71.52 ± 12.50 71.52 ± 13.53 0.00 ± 16.10 p2,1 < 0.05 p2,4 > 0.05 p4,3> 0.05 > 0.05 83 Journal of military pharmaco-medicine No7-2017 FEV1 (%pred) X ± SD 34.67 ± 15.02 Change 35.73 ± 15.05 37.26 ± 12.03 p2,1 > 0.05 p2,4 > 0.05 p4,3 < 0.05 33.65 ± 10.06 1.06 ± 6.45 -3.61 ± 7.24 < 0.05 (9.09) (4.35) > 0.05 Increase > 10% (n) (%) RV (%pred) X ± SD 250.27 ± 73.,88 Change 215.00 ± 60.70 251.43 ± 64.93 -35.27 ± 62.00 p2,1 < 0.01 p2,4 < 0.01 p4,3 > 0.05 275.09 ± 88.56 23.65 ± 60.72 0.001 TLC (%pred) X ± SD 138.12 ± 24.01 Change 126.15 ± 22.25 144.70 ± 24.84 -11,97 ± 27,43 154.39 ± 35.47 p2,1 < 0.05 p2,1 < 0.01 p4,3 > 0.05 9.70 ± 24.45 < 0.01 Raw (cmH20/l/sec) X ± SD 9.04 ± 4.31 Change 10.07 ± 4.50 9.72 ± 4.41 1.03 ± 3.97 11.13 ± 4.77 p2,1 > 0.05 p2,4 > 0.05 p4,3 > 0.05 1.41 ± 5.44 > 0.05 After month therapy, the mean of FVC and FEV1 increased, while RV and TLC decreased Especially, patients (9.09%) had the improvement of FEV1 more than 10% pred The improvement of FVC, RV and TLC was significant after therapy (p < 0.05) The patients in the group II had also improvement of respiratory indexes, but insignificantly (p > 0.05) In comparison with group II, the increase of FVC and decrease of RV and TLC of patients in group I was significantly higher (p < 0.05) However, Raw of patients in the both groups increased insignificantly (p > 0.05) Table 6: Complications and adverse events Complications and adverse events n % 12.12 Exacerbations of COPD 9.09 Pneumothorax 3.03 21.21 Hemoptysis 6.06 Early Later Blocked valve because of mucus 9.09 Granulation around the valve 6.06 The portion of early adverse events was 12.12%, in which 9.09 % of exacerbations of COPD and 3.03% of pneumothorax The common later adverse events were the blocked valve because of mucus, granulation around the valve and hemoptysis, with the rate following by 9.09%, 6.06% and 6.06%, respectively 84 Journal of military pharmaco-medicine no7-2017 DISCUSSION Clinical and respiratory function characteristics * Characteristics of age and gender: all of patients in the treatment group were male; with the mean of age was 65.70 ± 7.32 years old This characteristics was similar to it in controlled group The age of patients in our study had also no difference in comparison with other studies in the world, such as the study about the efficacy of bronchial valve in treatment emphysema was carried out by Sciurba F.C et al (2010) (VENT study) in 220 patients, with the mean of age was 65.34 ± 6.83 years old and the portion of males was 60.4% [8] In 284 patients who were located one-way bronchial valve in the study of Valipour A et al (2013), mean of the age was 63 ± 7.5 years old, in which the rate of male was 63% [10] * Clinical characteristics: The patients who were located one-way bronchial valve had long duration of disease, low BMI, high CAT score and decreased 6MWD This meant that the status of nutrition was low and COPD had affected much to the life and health of COPD patients To compare with the studies of Sterman et al (2010) and Eberhardt R et al (2012), the patients in our study had similar mean of 6-MWD However, the mean of BMI was significantly lower than that in previous studies of other authors [2, 9] The status of nutrition and effects of COPD to the quality of life were important factors which affected the efficacy of the technique to reduce lung volume by oneway bronchial valve in patients with severe emphysema * Characteristics of respiratory function: In this study, severe emphysema was seen most in the lower lobe, with the portion of 63.64% in the group I and 96.97% in the group II The mean of VC, FEV1, FVC and PaO2 decreased and the opposite was seen in RV, TLC, Raw and PaCO2 in two groups of patients There was no difference in FEV1, VC, RV, TLC and Raw between two groups (p > 0.05) This was the different point of studied patients in our trial, with the high portion of severe emphysema was seen in the lower lobe This difference could be explained that all of the patients in our study were in the severe stage of disease, leading to the high rate of pan lobular emphysema The changes of respiratory function indexes in our study were similar to those in previous studies such as in the study of Wan I.Y et al (2006), the mean of FEV1 was 30.1 ± 10.7% pred, RV and TLC followed by 244.3 ± 60.3% pred and 128.4 ± 17.1% pred [11]; Sciurba F.C et al (2010) studied to place bronchial valve for patients with the mean of FEV1, FVC, TLC and RV followed by 30 ± 8%, 70 ± 15%, 124 ± 15% and 216 ± 44% pred [8] Quantity and location of bronchial valve The rate of valve with the size 5.5 mm used was 75.00% 31 patients was treated with only one (94.94%), one patient (3.03%) with two and one patient (3.03%) with valves The portion of valve located in the right lung was 88.88%, in which the most was seen in the right lower lobe (55.55%) and only valves (11.12%) were located in the left 85 Journal of military pharmaco-medicine No7-2017 lung In our study, the quantity of valve was quite few because the patients had to pay much for this technique So that, the quantity and location of valve for patients in our study were different from that in the previous studies, such as Wan I.Y.P et al (2006) placed ± 1.6 valves per patient, with the most of valves in the upper lobes of lungs, in which the portion of valves in the right upper lung was 39.8% [11] Park T.S et al (2015) conducted this technique in 43 patients, with the mean of valve per patient was 3, the rate of valve in the right upper lobe, left lower lobe, right lower lobe and left upper lobe followed by 41.9%, 34.9%, 14% and 2.3% [7] Davey C et al (2015) placed averagely valves per patient (from to valve per patient) [1] Results of bronchoscopic lung volume reduction with one-way bronchial valve * Change of clinical symptoms after therapy: At months after therapy, BMI of patients in both groups changed insignificantly The patients in the group I witnessed the significant increase of 6-MWD (p < 0.01), in which 16 patients (48.48%) had more than 26 meters Most of patients in the group I decreased CAT index significantly (p < 0.01), with the improvement was more than points in 75.76% of patients A similar trend was seen in the decrease of mMRC in the group I (p < 0.01) In comparison with the group II, the group I had a significant improvement of 6-MWD, CAT and mMRC (p < 0.05) However, the degree of improvement in the quality of life 86 (decrease the CAT point) and increase of the ability for physical activity in our study was less than that in some previous studies, such as being placed averagely 3.8 valve per patient at months after therapy, the patients in the study of Sciubar F.C et al (2010) had the significant improvement of the degree of dyspnea, with the average decrease of SQRG was -2.8, mMRC was -0.1 points and the average increase of 6-MWD was 9.3 meters This change was significantly different from that in the controlled group (p = 0.04) [8] In the study of Valipour R et al (2013), at months after placing valve per patient, there was a significant improvement in the BODE index of the treatment group in comparison with that in controlled group (p < 0.001) [10] The results of the study of Davey C et al (2015) had shown that at months after placing averagely valves per patient, 52% of patients increased 6-MWD more than 26 meters and 57% of patients decreased more than CAT points This improvement was significantly different from that in the controlled group [1] To compare with other previous studies, the difference of the change in clinical characteristics after therapy in our study could be explained by some following factors, including the less quantity of valves per patient, the disobedience of patients in treatment of stable COPD and the short time of follow-up (only in months) * Changes in respiratory function indexes: At months after therapy, the mean of FVC and FEV1 increased, while RV and Journal of military pharmaco-medicine no7-2017 TLC decreased Especially, patients (9.09%) had the improvement of FEV1 more than 10% predicted The improvement of FVC, RV and TLC was significant after therapy (p < 0.05) The patients in the group II also had an improvement of respiratory indexes, but insignificantly (p > 0.05) In comparison with the group II, the increase of FVC and decrease of RV and TLC of patients in the group I was significant higher (p < 0.05) However, Raw of patients in the both groups increased insignificantly (p > 0.05) That meant that one-way bronchial valve had the effect to reduce lung volume and improve respiratory function in COPD patients To compare with the previous studies, we found that the changes of the respiratory function indexes were lower In the study of Yim et al (2004), while FVC and FEV1 improved significantly, the change of RV and TLC after months was not remarkable [12] Klooster K et al (2015) showed that the patients who were placed averagely valves after months follow-up witnessed the noticeable increase of FEV1, FVC in comparison with the controlled group (p < 0.05) [5] The more significant change of FEV1 was seen in the results of the study of Park T.S et al (2015), with the mean of FEV1 of the patients placed averagely valves after months follow-up increasing from 0.68 ± 0.26 to 0.92 ± 0.4 liters [7] In the study of Klooster K et al (2015), patients who were placed averagely valves per patient decreased RV significantly [5] The mean of RV and TLC of the patients placed averagely 6.7 valves in the study of Sterman D.H et al (2010) changed inappreciably in all of times at 1, 3, and 12 after the technique [9] In conclusion, the degree of reduction of RV and TLC and the change of FEV1 depended on the quantity of placed valves and the different moments of assessment in study Complications and adverse events The portion of early adverse events was 11.76%, in which 9.09% of exacerbations of COPD and 3.03% of pneumothorax Sterman D.H et al (2010) followed up 91 patients after therapy and witnessed that one patient had respiratory failure and heart attack, patients had to perform valve removal because the constant bronchospasm, patients developed pneumonia at the place of valve, patients suffered pneumothorax with death [9] The common later adverse events were the blocked valve because of mucus, granulation around the valve and hemoptysis, with the rate following by 9.99%, 6.06% and 6.06% In the study of Sciubar F.C et al (2010) in 214 patients after months, the general portion of complications was 4.2%, including pneumothorax (4.2%), pneumonia (3.2%), hemoptysis (5.6%), COPD exacerbations (7.9%) and 85 valves were removed in 31 patients after 12 months [8] In our study, the portion of complications and adverse events was less than in the previous studies That may relate directly to the quantity of placed valves, the duration and times of the technique In general, this technique is relative safe, with the low portion and light degree of adverse events 87 Journal of military pharmaco-medicine No7-2017 CONCLUSIONS Evaluated the results of one-way valve placement in treatment of severe emphysema in 33 stable COPD patients, in which 31 patients were placed one and 27 valves with the size 5.5 mm were used, the results had shown that most of patients witnessed the improvement of the quality of life (decrease CAT points), increase in ability of physical activity, increase in FVC and decrease in RV and TLC after months The portion of patients who improved BMI, FEV1 and Raw was lower The complications and adverse events after this therapy were few and mild REFERENCES Davey C, Zoumot Z, Jordan S et al Bronchoscopic lung volume reduction with endobronchial valves for patients with heterogeneous emphysema and intact interlobar fissures (the BeLieVeR-HIFi study): a randomised controlled trial Lancet 2015 386, pp.1066-1073 Eberhardt R, Gompelmann D, Schuhmann M et al Complete unilateral vs partial bilateral endoscopic lung volume reduction in patients with bilateral lung emphysema Chest 2012, 142 (4), pp.900-908 Emmanuil P, Koufos N, Koulouris N et al Bronchoscopic lung volume reduction in advanced pulmonary emphysema: the safety and efficacy of novel methods Pneumon Number 2012, 25 (1), pp.35-49 Global intiative for chronic obstructive lung disease Global strategy for diagnosis, 88 management and prevention of chronic obstructive pulmonary disease Update 2013 Klooster K, Ten Hacken N.H.T, Hartman J.E et al Endobronchial valves for emphysema without interlobar collateral ventilation N Engl J Med 2015, 373, pp.2325-2335 National Emphysema Treatment Trial Research Group Cost effectiveness of lungvolume-reduction surgery for patients with severe emphysema N Engl J Med 2003, 348, pp.2092-2102 Park T.S, Hong Y, Lee J.S Bronchoscopic lung volume reduction by endobronchial valve in advanced emphysema: the first Asian report Int J Chron Obstruct Pulmon Dis 2015, 10, pp.1501-1511 Sciurba F.C, Ernst A, Herth F.J et al A randomized study of endobronchial valves for advanced emphysema, N Engl J Med 2010, 363, pp.1233-1244 Sterman D.H, Mehta A.C, Wood D.E et al A multicenter pilot study of a bronchial valve for the treatment of severe emphysema Respiration 2010, 79, pp.222-233 10 Valipour A, Herth F.J, Burghuber O.C et al Target lobe volume reduction and COPD outcome measures after endobronchial valve therapy Eur Respir J 2013, 43, pp.387-396 11 Wan I.Y, Toma T.P, Geddes D.M et al Bronchoscopic lung volume reduction for endstage emphysema: report on the first 98 patients Chest 2006, 129, pp.518-526 12 Yim A.P.C, Hwong T.M.T, Lee T.W et al Early results of endoscopic lung volume reduction for emphysema J Thorac Cardiovasc Surg 2004, 127, pp.1564-1573  ... of adverse events 87 Journal of military pharmaco-medicine No7-2017 CONCLUSIONS Evaluated the results of one- way valve placement in treatment of severe emphysema in 33 stable COPD patients, in. .. [3] In Vietnam, this technique has been done firstly in the 103 Military Hospital from 2014 The purpose of this study: To evaluate the results of one- way valve placement in treatment of severe emphysema. .. bronchoscopy lung volume reduction with one- way bronchial valve in treatment of emphysema Table 4: Changes of clinical characters of patients in groups after months Index Group I Before technique (1)