Abstract
Background
After relieving stenosis with an airway silicone stent in post-tuberculosis bronchial stenosis (PTTS), stent removal is attempted if it is determined that airway patency can be maintained even after stent removal. However, the factors affecting airway stent removal are not well known. We investigate the factors that enable the successful removal of airway silicone stents in patients with PTTS.
Methods
We retrospectively analyzed PTTS patients who underwent bronchoscopic intervention from January 2004 to December 2019. Successful stent removal is defined as airway patency maintained when the stent is removed, so that reinsertion of the stent is not required. A multivariate logistic regression analysis was used to identify independent factors associated with successful stent removal at the first attempt.
Results
Total 344 patients were analyzed. Patients were followed up for a median of 47.9 (26.9–85.2) months after airway stent insertion. Approximately 69% of PTTS patients finally maintained airway patency after the stent was removed. Factors related to successful stent removal at the first attempt were older age and male sex. Absence of parenchymal calcification, segmental consolidation & bronchiolitis, and no trachea involved lesion were relevant to the successful stent removal. Stent dwelling for 12–24 months was associated with successful stent removal compared to a duration of less than 12 months.
Conclusion
For patients whose airway patency is determined to be maintained even without a stent, it is necessary to attempt stent removal in consideration of factors related to successful stent removal.
Keywords: Post-Tuberculosis Tracheobronchial Stenosis, Bronchoscopic Intervention, Airway Silicone Stent
Graphical Abstract
INTRODUCTION
Airway tuberculosis could cause bronchial stenosis and atelectasis despite treatment with effective anti-tuberculosis agents.1,2 Post-tuberculosis tracheobronchial stenosis (PTTS) is the most common cause of benign bronchial stenosis in tuberculosis-endemic areas.3 PTTSs constitute varying degrees of stenosis, from mild to complete obstruction, and in some cases, might require intervention.4 Bronchoscopic interventions have been proposed as treatments for patients with PTTS.5,6 Several studies have reported that bronchoscopic intervention and the use of silicone stents are effective and safe methods for treating patients with PTTS.7 Additionally, studies have shown that silicone stents are tolerable, even after long-term placement in the airway.8
An airway stent is necessary to resolve airway narrowing, but stent-related complications such as stent migration, mucostasis, and granulation tissue growth can occur.9 Further, silicone stent can cause sputum production, cough, and halitosis, reducing the quality of life of patients. Therefore, it is necessary to properly withdraw the silicone stent as soon as it is determined that the patient's airway patency can be maintained without a stent. A previous study reported successful stent removal in more than half (56%) of all patients with PTTS with silicone stents.10 Also, previous studies have suggested that several factors are associated with successful stent removal.10,11,12 However, all of these studies were studies with fewer than 100 patients.10,11,12 Therefore, we investigate the clinical outcomes of bronchoscopic intervention in patients with PTTS and evaluate the factors that enable the successful removal of airway silicone stents.
METHODS
Study population
Samsung Medical Center, a university-affiliated hospital in South Korea, began bronchoscopic intervention in 1999. We retrospectively analyzed patients with PTTS over the age of 18 years who underwent bronchoscopic intervention by rigid bronchoscopy between January 2004 and December 2019. We excluded patients without a sufficient follow-up period (≤ 1 months) after stenting. This study included some participants from previous studies conducted on PTTS patients at the same center.10,11,12
Bronchoscopic intervention & silicone airway stent
Bronchoscopic intervention was performed according to standard techniques.13,14 After the induction of general anesthesia, the patient was intubated with a rigid bronchoscope (Bryan Co., Woburn, MA, USA or Karl-Storz, Tuttlingen, Germany). A flexible bronchoscope (EVIS BF 1T260; Olympus Co., Tokyo, Japan) was passed through the rigid bronchoscope, and the airway status was evaluated. Various combinations of intervention techniques have been used for this purpose. Stenosis was dilated by mechanical debulking and ballooning and/or using laser (neodymium-doped yttrium aluminum garnet laser [LaserSonics, Milpitas, CA, USA] or diode laser [Biolitec, Ceralas®, Germany]) therapy. Furthermore, a silicone stent (Natural stent 15,16 [M1S Co., Seoul, Korea] or Dumon stent [Novatech, La Ciotat, France]) was inserted to maintain airway patency if required. Dumon stents have been commercially available for medical use in South Korea since 2015. An angulated stent was prepared as a silicone prosthesis cut cross-sectionally at an oblique angle using standard Mayo scissors, and then reattached with 3-0 silk sutures to approximate the angled alignment of the tortuous airways.17 For cases requiring Y-stents, in our center, Natural stents or Dumon stents with suitable length and diameter are used by making a Y-shape with silk sutures.
After bronchoscopic intervention, the patient underwent outpatient follow-up after one month later, after then followed by 3 or 6 month intervals. However, if it was judged that more close monitoring was needed, follow-up was performed at shorter intervals than suggested. The timing of stent removal was determined by the clinician, and various clinical factors of the patient at that time were considered. Surgery was considered when PTTS was not successfully resolved despite intervention procedure and restenosis or procedure-related complications occurred repeatedly.
Data collection
The following information was collected from the database: patient-related factors such as demographic characteristics, performance status, tuberculosis activity, duration from diagnosis of tuberculosis to intervention, symptoms, and spirometry results; lesion-related factors such as the site of stenosis, single or multiple lesions, type of obstruction, severity, and length of stenosis, and findings of chest computed tomography (CT) (Supplementary Fig. 1); and procedure-related factors such as methods of stenosis dilatation, type of silicone stent, and use of an angulated stent.
Active tuberculosis was defined as the presence of acid-fast bacilli by polymerase chain reaction, staining or culture of Mycobacterium tuberculosis from sputum, bronchial aspirate, or bronchial biopsy at the time of the procedure. The performance status was assessed using the American Society of Anesthesiologists (ASA) physical status classification. Poor performance status was defined as ASA class III or IV.18 The Myer-Cotton stenosis grading system was used to classify the severity of airway stenosis as follows: grade I, ≤ 50% luminal stenosis; grade II, 51–70% luminal stenosis; grade III, 71–99% luminal stenosis; and grade IV, no lumen.19
Successful stent removal is defined as airway patency maintained when the stent is removed, so that reinsertion of the stent is not required.
Statistical analysis
Data are presented as numbers (%) for categorical variables and medians (interquartile range [IQR]) for continuous variables. Categorical data were compared using the χ2 test or Fisher’s exact test, and continuous data were compared using the Mann-Whitney test or Kruskal-Wallis test. Multivariate logistic regression analysis with backward stepwise selection (entry of variables, P < 0.050; removal of variables, P > 0.100) was performed to identify independent factors associated with successful stent removal at the first attempt. Statistical significance was set at P < 0.050. All statistical analyses were performed using SPSS software (IBM SPSS Statistics ver. 27, Chicago, IL, USA).
Ethics statement
This study was performed in accordance with the Declaration of Helsinki and approved by the Samsung Medical Center Institutional Review Board (IRB No. 2022-03-049) to review and publish information acquired from patient records. The requirement for informed consent was waived because patient information was de-identified and anonymized prior to the analysis.
RESULTS
Baseline characteristics
Out of a total of 458 patients, 319 patients underwent silicone airway stent insertion whereas 139 patients only underwent a procedure to widen the airway stenosis. Subsequently, 62 of the 139 patients had an airway stent inserted to maintain airway patency. Total 381 patients underwent airway stent insertion during the study period. However, cases in which follow-up data were lost immediately after airway stent insertion were excluded. Finally, 344 patients were included (Fig. 1). Patients were followed up for a median of 47.9 (26.9–85.2) months after airway stent insertion.
Fig. 1. Flowchart of the study population.
PTTS = post-tuberculosis tracheobronchial stenosis.
aOf the 458 patients, 319 patients had stents placed in the first procedure, and 62 patients did not have stents placed in the first procedure but needed stents in subsequent procedures. Of these 381 patients, 37 patients were excluded from insufficient follow-up period after stenting, resulting in 344 patients.
Baseline characteristics of the 344 patients are presented in Table 1. The median age was 43 (31–52) years, and the majority were females (82%). At the time of the procedure, more than 90% of patients did not have active tuberculosis. The median duration from tuberculosis diagnosis to intervention was 50.6 (8.4–221.0) months. On chest radiography, 187 (54.4%) patients had atelectasis due to airway stenosis, and atelectasis of the left upper lobe (partial, 9.3%; complete, 19.8%) and left lower lobe (partial, 4.1%; complete, 15.4%) were common. Among patients with lung parenchymal lesions on chest CT, 27 (7.8%) had parenchymal calcification, 23 (6.7%) had atelectasis with bronchiectatic volume loss, and 48 (14.0%) had segmental consolidation with bronchiolitis.
Table 1. Baseline characteristics of study population (N = 344).
| Variables | Values | |||
|---|---|---|---|---|
| Age, yr | 43 (31–52) | |||
| Sex, female | 282 (82.0) | |||
| BMI, kg/m2 | 22.0 (20.1–24.6) | |||
| ASA classa | ||||
| Class I, II | 298 (86.6) | |||
| Class III, IV | 46 (13.4) | |||
| Activity of TB on first intervention | ||||
| Active TB | 31 (9.0) | |||
| Past TB | 313 (91.0) | |||
| Duration from TB diagnosis to intervention, mon | 50.6 (8.4–221.0) | |||
| < 6 | 60 (17.4) | |||
| ≥ 6 and < 12 | 53 (15.4) | |||
| ≥ 12 | 231 (67.2) | |||
| Presenting symptoms at stenosis diagnosisb | ||||
| Dyspnea | 251 (73.0) | |||
| Cough | 141 (41.0) | |||
| Sputum | 101 (29.4) | |||
| Wheezing | 76 (22.1) | |||
| Fever | 41 (11.9) | |||
| Chest discomfort | 33 (9.6) | |||
| Duration from occurrence of symptoms to intervention, days | 50 (24–136) | |||
| Baseline spirometry (n = 316) | ||||
| FEV1 (% predicted) | 61 (52–70) | |||
| FVC (% predicted) | 76 (64–88) | |||
| FEV1/FVC (% predicted) | 67 (57–77) | |||
| Chest radiographyb | ||||
| Atelectasis | 187 (54.4) | |||
| Right upper lobe | ||||
| Partial | 4 (1.2) | |||
| Complete | 32 (9.3) | |||
| Right middle lobe | ||||
| Partial | 5 (1.5) | |||
| Complete | 20 (5.8) | |||
| Right lower lobe | ||||
| Partial | 6 (1.7) | |||
| Complete | 19 (5.5) | |||
| Left upper lobe | ||||
| Partial | 32 (9.3) | |||
| Complete | 68 (19.8) | |||
| Left lower lobe | ||||
| Partial | 14 (4.1) | |||
| Complete | 53 (15.4) | |||
| Complete atelectasis more than 1 lobe | 56 (16.3) | |||
| Atelectasis less than 1 mon | 52 (15.1) | |||
| Airway lesions | ||||
| Calcified enlarged lymph nodes around the airway | 83 (24.1) | |||
| Active infectious condition for bronchus | 30 (8.7) | |||
| Lung parenchymal lesions | ||||
| Parenchymal calcification | 27 (7.8) | |||
| Atelectasis with bronchiectatic volume loss | 23 (6.7) | |||
| Segmental consolidation with bronchiolitis | 48 (14.0) | |||
Data are presented as number (%) or the median (interquartile range).
BMI = body mass index, ASA = American Society of Anesthesiologists, TB = tuberculosis, FEV1 = forced expiratory volume in 1 second, FVC = forced vital capacity.
aASA physical status class ≥ 3 means severe systemic disease with functional limitation.
bPatients could have more than one lesion.
Most patients (n = 297, 86.3%) had a single stenosis lesion and 14% had multiple lesions involving two or more airways. Among patients with a single lesion, the left main bronchus lesion was the most common lesion (212 [61.6%] patients), followed by tracheal lesions (26 [7.6%] patients). Among patients with multiple lesions, 43 (43/47, 91.5%) patients had tracheal involvement (Table 2).
Table 2. Bronchoscopic findings and parameters of intervention (N = 344).
| Variables | Values | ||
|---|---|---|---|
| Site of stenosis | |||
| Single lesion | 297 (86.3) | ||
| Trachea | 26 (7.6) | ||
| Left main bronchus | 212 (61.6) | ||
| Left lower bronchus | 1 (0.3) | ||
| Right main bronchus | 18 (5.2) | ||
| Right bronchus intermedius | 23 (6.7) | ||
| Right main bronchus & bronchus intermedius | 17 (4.9) | ||
| Multiple lesion | 47 (13.7) | ||
| Trachea and one or both bronchi | 43 (12.5) | ||
| Both bronchi except trachea involvement | 4 (1.2) | ||
| Type of obstructiona | |||
| Fibrous stricture | 310 (90.1) | ||
| Malacia | 50 (14.5) | ||
| Granulation tissue & airway inflammation | 44 (12.8) | ||
| Severity of stenosis (Myer and Cotton grade)b | |||
| II | 97 (28.2) | ||
| III | 180 (52.3) | ||
| IV | 67 (19.5) | ||
| Length of stenosis, mmc | 45 (38–50) | ||
| Details of 1st procedure | |||
| Method of airway dilatationd | |||
| Ballooning | 211 (61.3) | ||
| Laser | 16 (4.7) | ||
| Type of silicone stent | |||
| Tube stent | 336 (97.7) | ||
| Natural stent | 224 (65.1) | ||
| Dumon stent | 112 (32.6) | ||
| Y stent | 8 (2.3) | ||
| Angulated stent | 19 (5.5) | ||
Data are presented as number (%) and median (interquartile range).
aPatients could have more than one type of airway obstruction.
bCategorization based on the percentage of reduction in cross-sectional area. Grade 1, ≤ 50% lumenal stenosis; Grade II, 51–70% lumenal stenosis; Grade III, 71–99% lumenal stenosis; Grade IV, no lumen.
cLength of MCAO was defined as the sum of the length of the obstructive lesions more than grade II.
dPatients could undergo more than one method of airway dilatation.
Outcomes of bronchoscopic intervention
Of the 285 patients who underwent stent removal, only 226 were stable and 59 had recurrent stenosis. Of these, three patients underwent surgery, and stents were re-inserted in 56 patients. Of the 59 patients in whom stent removal could not be attempted, three eventually underwent surgery. Fifty-six patients had stents remaining, and stent removal was not possible in 40 patients after reinsertion. Finally, 239 patients remained stable even after stent removal (Fig. 1). Among the patients who underwent stent reinsertion due to stent removal failure, 51 patients underwent reinsertion once, four patients underwent reinsertion twice, and one patient underwent reinsertion thrice (Supplementary Fig. 2). During study period, 78.9% of patients maintained their stents for over 12 months, and total duration of stent placement was median 24.8 (16.4–44.7) months. In 56 patients who underwent stent re-insertion, the duration between stent removal to re-insertion was 1.6 (IQR, 1.0–9.9) months (Supplementary Table 1). Silicone stent free time curves for 56 patients who underwent re-insertion are shown in Supplementary Fig. 3.
Factors related to successful stent removal at the first attempt
The factors related to successful stent removal at the first attempt are shown in Table 3. In the multivariate analysis, age (adjusted odds ratio [aOR], 1.04; 95% confidence interval [CI], 1.02–1.07; P = 0.001), male sex (aOR, 5.73; 95% CI, 1.49–22.03; P = 0.011) influence the success of stent removal at the first attempt. Among the various CT findings, parenchymal calcification (aOR, 0.07; 95% CI, 0.02–0.25; P < 0.001), and segmental consolidation with bronchiolitis (aOR, 0.26; 95% CI, 0.11–0.59; P = 0.002) were associated with stent removal failure at the first attempt. Airway stenosis involving trachea (aOR, 0.21; 95% CI, 0.09-0.49; P < 0.001) were less relevant to successful stent removal than stenosis not involving trachea. Stent retention for ≥ 12 & < 18 months (Reference, < 6 months; aOR, 6.20; 95% CI, 1.48–25.97; P = 0.013) and ≥ 18 & < 24 months (Reference, < 6 months; aOR, 5.34; 95% CI, 1.42–20.04; P = 0.013) were significantly associated with successful stent removal at the first attempt.
Table 3. Factors related to successful stent removal at the first attempt (N = 285).
| Variables | Univariable analysis | Multivariable analysis | ||||
|---|---|---|---|---|---|---|
| Unadjusted OR (95% CI) | P | Adjusted OR (95% CI) | P | |||
| Patient-related factors | ||||||
| Age, yr | 1.03 (1.01–1.05) | 0.016 | 1.04 (1.02–1.07) | 0.001 | ||
| Sex, male | 3.61 (1.25–10.47) | 0.018 | 5.73 (1.49–22.03) | 0.011 | ||
| BMI, kg/m2 | 1.07 (0.98–1.17) | 0.140 | ||||
| ASA classa | ||||||
| I, II | Reference | |||||
| III, IV | 1.40 (0.56–3.54) | 0.472 | ||||
| CT finding | ||||||
| Atelectasis more than one lobe | 0.53 (0.26–1.08) | 0.078 | ||||
| Calcified enlarged lymph nodes around the airway | 0.51 (0.27–0.96) | 0.038 | ||||
| Active inflammation in airway | 0.20 (0.08–0.48) | < 0.001 | ||||
| Lung parenchymal lesion | ||||||
| Parenchymal calcification | 0.16 (0.06–0.43) | < 0.001 | 0.07 (0.02–0.25) | < 0.001 | ||
| Atelectasis with bronchiectatic volume loss | 1.05 (0.22–5.06) | 0.956 | ||||
| Segmental consolidation with bronchiolitis | 0.24 (0.12–0.50) | < 0.001 | 0.26 (0.11–0.59) | 0.002 | ||
| Atelectasis within 1 month | 1.20 (0.54–2.63) | 0.658 | ||||
| FEV1 (% predicted)b | ||||||
| ≥ 50% | Reference | |||||
| < 50% & ≥ 30% | 0.42 (0.20–0.87) | 0.019 | ||||
| < 30% & no results of PFT | 0.48 (0.18–1.24) | 0.129 | ||||
| Lesion-related factors | ||||||
| Location of stenosis | ||||||
| Non-trachea lesion | Reference | Reference | ||||
| Trachea lesion | 0.27 (0.14–0.54) | < 0.001 | 0.21 (0.09–0.49) | < 0.001 | ||
| Severity of stenosis (Myer and Cotton grade)c | ||||||
| II | Reference | |||||
| III, IV | 0.86 (0.45–1.66) | 0.658 | ||||
| Type of stenosis | ||||||
| Fibrosis | 1.05 (0.41–2.72) | 0.920 | ||||
| Malacia | 1.41 (0.59–3.35) | 0.439 | ||||
| Granulation tissue & inflammation | 0.83 (0.35–1.94) | 0.665 | ||||
| Stenosis length, mm | 0.97 (0.95–1.00) | 0.047 | ||||
| Procedure-related factors | ||||||
| Type of stent | ||||||
| Tube stent | Reference | |||||
| Y stent | 0.51 (0.09–2.87) | 0.448 | ||||
| Stent angulation, yes | 2.03 (0.45–9.12) | 0.358 | ||||
| Duration of stent, mon | ||||||
| < 6 | Reference | Reference | ||||
| ≥ 6 & < 12 | 2.76 (0.81–9.38) | 0.105 | 3.76 (0.88–15.98) | 0.073 | ||
| ≥ 12 & < 18 | 4.91 (1.39–17.30) | 0.013 | 6.20 (1.48–25.97) | 0.013 | ||
| ≥ 18 & < 24 | 2.84 (0.93–8.67) | 0.066 | 5.34 (1.42–20.04) | 0.013 | ||
| ≥ 24 | 1.48 (0.57–3.83) | 0.420 | 2.79 (0.87–8.95) | 0.084 | ||
OR = odds ratio, CI = confidence interval, BMI = body mass index, CT = computed tomography, ASA = American Society of Anesthesiologists, FEV1 = forced expiratory volume in 1 second, PFT = pulmonary function test.
aASA physical status class ≥ 3 means severe systemic disease with functional limitation
bTwenty-seven patients had no results of pre-procedure PFT for the following reasons: PFT fail due to severe dyspnea (n = 12), emergency procedure decided while hospitalized through emergency room (n = 11), admitted to the intensive care unit in an intubation state (n = 4). Patients without PFT results were assigned to the same group as those with predicted FEV1 less than 30%.
cCategorization based on the percentage of reduction in cross-sectional area. Grade 1, ≤ 50% lumenal stenosis; Grade II, 51–70% lumenal stenosis; Grade III, 71–99% lumenal stenosis; Grade IV, no lumen.
DISCUSSION
We analyzed 344 patients who underwent airway silicone stent insertion through bronchoscopic intervention based on 20 years of procedural experience. To the best of our knowledge, this study reports long-term follow-up results with the largest number of airway stenting procedures in patients with PTTS thus far. In approximately 69% of patients, airway patency was finally maintained after stent removal. Factors related to successful stent removal at the first attempt were age, sex, presence or absence of parenchymal lesions, location of the stenosis, and duration of stent dwelling.
The usefulness of silicone airway stents in benign stenosis, such as PTTS,7 and the safety of long-term placement of silicone stents have already been demonstrated.8,20 However, the silicone stent is a foreign body, and although silicone stent-related complications are usually non-fatal; stent-related complications, such as stent migration, mucostasis, and granulation tissue growth, require additional procedures.9 Since stents can reduce quality of life due to sputum/cough/odor, it is recommended to remove the stent if possible.
In our study, interestingly, older age was associated with successful stent removal. We hypothesize the following: older patients are physically less active than younger patients; therefore, after stent removal, there is a possibility that some newly developed mild stenosis will remain asymptomatic. Since young patients are active, they may complain of more severe symptoms than elderly patients even when the airway is slightly narrowed after removing the stent. When bronchoscopic intervention is performed, airway status is important, but subjective symptoms also affect the decision of interventionist; therefore, even with the same airway status, stent reinsertion may frequently occur in younger patients. Additionally, it may be easier to decide and conduct stent reinsertion in younger patients than in older patients because younger individuals have a better performance status for re-procedure under general anesthesia.
Male sex was also associated with successful stent removal, and this may explain why endobronchial tuberculosis is more common in females. It is estimated that endobronchial tuberculosis is more common in females because of the narrower structure of the bronchus.21,22,23,24 This structural difference in airways could also explain why the stable state was more consistently maintained in males after stent removal.
Lee et al.25 reported chest CT features as predictors of treatment outcome after bronchoscopic intervention in patients with PTTS. They suggested that parenchymal calcification and bronchiectasis within atelectasis were associated with the failure of re-expansion after procedures. In our study, the occurrence of these parenchymal lesions, such as parenchymal lesions with calcification and segmental consolidation with bronchiolitis, is related to the failure of stent removal. Parenchymal calcifications result from chronic inflammation due to calcium deposition in the scar tissue.26 Further, segmental consolidation with bronchiolitis indicates tuberculosis infection involvement in the airway and parenchyme. This infection status could cause bronchiectasis which is a chronic condition characterized by irreversible airway dilatation due to airway damage and remodeling caused by airway inflammation or infection. Therefore, it can be assumed that the outcome of bronchoscopic interventions depends on the degree of irreversible parenchymal involvement of the lungs.
In our study, tracheal lesions were associated with the failure of stent removal. Shin et al.27 reported the outcomes of bronchoscopic intervention for post-intubation tracheal stenosis (PITS) and post-tracheostomy tracheal stenosis; the airway stent removal rates were 46% and 33%, respectively. Although this study did not include patients with PTTS, it showed that the stent removal rate was low in patients with tracheal lesions. Additionally, in our study, most multiple lesions had tracheal involvement. Therefore, it might be difficult to remove the stent and maintain a stable state in patients with tracheal lesion.
Many researchers have questioned whether it is most appropriate to remove the stent after resolving airway stenosis through procedures and stenting. Eom et al.11 reported that stent placement for > 12 months could reduce restenosis after stent removal in patients with PTTS. This study explained that recovery of the tracheobronchial mucosal trauma induced by mechanically dilatation procedures28,29 might take at least 12 months. In our study, a stent dwelling duration ≥ 12 & < 18 months and ≥ 18 & < 24 months were associated with successful stent removal for the first attempt. Rather, stent dwelling for more than 24 months was not statistically significantly associated with successful stent removal. There were cases in which the stent was stably maintained for more than 24 months and then removed: however, there were cases in which the stent could not be removed for more than 24 months due to frequent repeated procedures caused by various stent-related complications or recurrence of stenosis of the lesion. We suggest this is why more than 24 months of stent dwelling is not a factor related to successful stent removal. Also, if airway silicone stents are maintained for too long (≥ 24 months), removal failure is likely to occur due to stent-related complications, such as granulation tissue overgrowth and mucostasis-induced inflammation.
Our study has several limitations. First, it was conducted at a single referral center specializing in bronchoscopic intervention. During the study period, our center performed bronchoscopic intervention on central airway problems, which account for about 75% of all cases in South Korea30; therefore, our data may not be generalizable to other centers. Second, some factors related to successful stent removal included the subjective judgment of the clinician. For example, factors such as duration of stent dwelling included judgement of clinician who would have waited longer without attempting stent removal in patients considered to have poor airway patency after stent removal. Last, because our center does not perform routine follow-up CT scans or bronchoscopy after silicone stent removal, many patients did not receive follow-up exams unless problems arise after stent removal. Consequently, a limitation of this study is the lack of follow-up imaging data regarding stable patients after stent removal.
Nevertheless, we derived the results of this study based on the largest number of procedures performed on the PTTS patients and around 20 years of experience. The results of our study provide important clinical information for clinicians performing bronchoscopic interventions when removing silicone stents. Based on our study results, we found that in PTTS patients with no parenchymal abnormality and no involvement of the trachea, there is a high probability of maintaining airway patency even after the removal of silicone stents that have been in place for at least one year. In addition, we can expect that males with larger airway diameters will have a lower likelihood of restenosis after removal. Therefore, we recommend that clinicians consider removing silicone stents from PTTS patients who meet these conditions.
In conclusion, approximately 69% of PTTS patients were finally maintained their airway patency after stent removal. The factors affecting successful stent removal include older age, male sex, absence of parenchymal lesions, stenosis not involving trachea and duration of stent dwelling (≥ 12 & < 24 months). Our study provides robust evidence for successful stent removal in patients with PTTS and reports its long-term outcomes.
Footnotes
Disclosure: The authors have no potential conflicts of interest to disclose.
Data Availability Statement: The data that support the findings of this study are available from the corresponding author upon reasonable request.
- Conceptualization: Jeong BH, Kim HJ.
- Data curation: Kim BG, Jeong BH.
- Formal analysis: Kim BG.
- Investigation: Kim BG.
- Methodology: Kim BG.
- Supervision: Kim HJ.
- Visualization: Kim BG.
- Writing - original draft: Kim BG.
- Writing - review & editing: Kim BG, Jeong BH, Kim HJ.
SUPPLEMENTARY MATERIALS
Outcomes of bronchoscopic intervention for stent removal in patient with PTTS
Chest computed tomography findings in patients with post-tuberculosis bronchial stenosis. (A) Calcified enlarged lymph nodes around the airway, (B) active infectious condition for bronchus, (C) parenchymal calcification, (D) atelectasis with bronchiectatic volume loss, and (E) segmental consolidation with bronchiolitis.
The details in the patients who underwent stent reinsertion.
Silicone stent free time curve.
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Associated Data
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Supplementary Materials
Outcomes of bronchoscopic intervention for stent removal in patient with PTTS
Chest computed tomography findings in patients with post-tuberculosis bronchial stenosis. (A) Calcified enlarged lymph nodes around the airway, (B) active infectious condition for bronchus, (C) parenchymal calcification, (D) atelectasis with bronchiectatic volume loss, and (E) segmental consolidation with bronchiolitis.
The details in the patients who underwent stent reinsertion.
Silicone stent free time curve.