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Interventional Bronchoscopy in the Management of Airway Stenosis Due to Tracheobronchial Tuberculosis
bronchoscopy Interventional Bronchoscopy in the Management of Airway Stenosis Due to Tracheobronchial Tuberculosis* Yasuo Iwamoto, MD; Teruomi Miyazawa, MD, FCCP; Noriaki Kurimoto, MD, FCCP; Yuka Miyazu, MD; Astuko Ishida, MD; Keisuke Matsuo, MD; and Yoichi Watanabe, MD
Study objectives: To assess the efficacy and complications of interventional bronchoscopic techniques in treating airway stenosis due to tracheobronchial tuberculosis. Design: Case series. Setting: Respiratory care centers at two tertiary care referral teaching hospitals in Japan, Hiroshima City Hospital and Okayama Red Cross Hospital. Patients and interventions: A total of 30 patients were admitted to the hospital with a diagnosis of tracheobronchial tuberculosis between January 1991 and January 2002. Of those 11 patients received interventional bronchoscopy, including stent placement, laser photoresection, argon plasma coagulation (APC), balloon dilatation, cryotherapy, and endobronchial ultrasonography (EBUS). One patient with complete bronchial obstruction underwent a left pneumonectomy. Results: Six patients underwent stent placement after balloon dilatation, while the remaining five patients underwent only balloon dilatation. In six patients, Dumon stents were successfully placed to reestablish the patency of the central airways. Two patients first had Ultraflex stents implanted but had problems with granulation tissue formation and stent deterioration caused by metal fatigue due to chronic coughing. Dumon stents then were placed within the Ultraflex stents after the patient had received treatment with APC and mechanical reaming using the bevel of a rigid bronchoscope. In four patients, EBUS images demonstrated the destruction of bronchial cartilage or the thickening of the bronchial wall. The main complications of Dumon stents are migration and granulation tissue formation, necessitating stent removal, or replacement, and the application of cryotherapy to the granuloma at the edge of the stent. Conclusion: Interventional bronchoscopy should be considered feasible for management of tuberculous tracheobronchial stenosis. Dumon stents seem to be appropriate, since removal or replacement is always possible. Ultraflex stents should not be used in these circumstances because removal is difficult and their long-term safety is uncertain. EBUS could provide useful information in evaluating the condition of the airway wall in cases of tracheobronchial tuberculosis with potential for bronchoscopic intervention. (CHEST 2004; 126:1344 –1352) Key words: balloon dilatation; endobronchial ultrasonography; stent placement; tracheobronchial stenosis Abbreviations: APC ⫽ argon plasma coagulation; EBUS ⫽ endobronchial ultrasonography
tracheobronchial stenosis is a serious T uberculous clinical problem because it can cause obstructive pneumonia and dyspnea on exertion. Surgical resection and bronchoplastic reconstruction has long been the standard treatment.1,2 More recently, a variety of interventional bronchoscopic techniques has been developed,3–5 including stent placement,6 – 8 laser photoresection,9 argon plasma coagulation (APC),10 1344
balloon dilatation,11 cryotherapy12 and endobronchial ultrasonography (EBUS).13 The development and refinement of various airway stents and increased experience have broadened the indications for these procedures. We reported previously7,14 that stenting has become a valuable new therapeutic strategy for patients with malignant or benign tracheobronchial stenosis. However, the indications for Bronchoscopy
Table 1—Clinical Features, Interventions, and Outcomes in Tuberculous Tracheobronchial Stenosis* Patient/Sex/Age, yr 1/F/59 2/F/29 3/M/59 4/M/65 5/F/48 6/F/56 7/F/77 8/F/18 9/F/38 10/F/53 11/F/31 12/F/19
Symptoms
Sites of Lesions
Intervention
Outcome
Dyspnea Dyspnea Dyspnea Dyspnea Dyspnea Dyspnea Dyspnea Dyspnea Dyspnea Dyspnea Cough Dyspnea
Trachea, carina, LMB LMB LMB Trachea Trachea, carina, RMB Trachea RMB LMB LMB LMB LMB LMB
Balloon, Dumon Y, EBUS Balloon, Dumon, EBUS Balloon, Dumon, EBUS Balloon, Dumon Y, EBUS Balloon, APC, cryotherapy, Ultraflex, Dumon Y Balloon, APC, cryotherapy, Ultraflex, Dumon Balloon Balloon Balloon Balloon Balloon Left pneumonectomy
Improved Improved Improved Improved Improved Improved Improved Improved Unchanged Unchanged Unchanged Improved
*RMB ⫽ right main bronchus; LMB ⫽ left main bronchus; F ⫽ female; M ⫽ male.
stenting in patients with tuberculous tracheobronchial stenosis are difficult to understand, and prognosis is unclear. We carefully evaluated what might be the best interventional strategy in this complex situation. EBUS has been used in recent years to evaluate the individual layers of the bronchial wall. In our previous study,13,15 the images produced by EBUS correlated with histologic results. The third layer (hyperechoic) is the marginal echo on the inner side of the bronchial cartilage, and the fourth layer (hypoechoic) is the bronchial cartilage. Thus, we considered that EBUS might provide useful information for a planned bronchoscopic intervention. This report highlights patients with tracheobronchial tuberculosis in whom diagnosis and treatment were made by various methods of interventional bronchoscopy, including EBUS and stent placement for stenoses. Patients and Methods From January 1991 to January 2002, 30 patients with tracheobronchial tuberculosis were admitted to our institutions. Among these patients, treatment with antituberculous medication resulted in 18 patients recovering and remaining asymptomatic. *From the Department of Pulmonary Medicine (Drs. Iwamoto, Miyazawa, Miyazu, and Ishida), Hiroshima City Hospital, Hiroshima, Japan; the Department of Surgery (Dr. Kurimoto), Hiroshima National Hospital, Higashi-Hiroshima, Japan; and the Department of Pulmonary Medicine (Drs. Matsuo and Watanabe), Okayama Red Cross Hospital, Okayama, Japan. Received September 18, 2003; revision accepted April 22, 2004. Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (e-mail: [email protected]). Correspondence to: Teruomi Miyazawa, MD, PhD, FCCP, Director, Department of Pulmonary Medicine, Hiroshima City Hospital, 7–33 Naka-Ku, Moto-machi, Hiroshima City, Hiroshima Prefecture, 730-8518 Japan; e-mail: miyazawt@ carrot.ocn.ne.jp www.chestjournal.org
However, 12 patients developed dyspnea, severe cough, and repeated obstructive pneumonia due to tracheobronchial stenosis. These 12 patients were considered to be suitable candidates for intervention (bronchoscopy, 11 patients; pneumonectomy, 1 patient). The clinical characteristics are presented in Table 1. All patients were examined by flexible bronchoscopy (BF200; Olympus; Tokyo, Japan). The sites of bronchial lesions in each patient are also shown in Table 1. Before bronchoscopic intervention, written informed consent was obtained from all patients. After balloon dilatation (Accent Balloon Angioplasty Catheters; Cook Inc; Bloomington, IN) as well as gentle dilatation with the bevel of a rigid bronchoscope (Efer; La Ciolat, France) under general anesthesia and fluoroscopic visualization, the Dumon stent (Novatech; Aubagne, France) and the Ultraflex stent (Boston Scientific; Natick, MA) were placed according to the technique recommended by their originators.6,8 Endobronchial APC (APC; Erbe USA; Marietta, GA) was performed via a flexible bronchoscope (energy applied, 30 to 40 W; argon flow, 1.6 L/min). A monopolar APC probe, 220 cm in length and 2.3 mm in diameter, was inserted through the working channel of the bronchoscope. The target tissue was visualized endoscopically and then coagulated. The coagulated tissue then was removed mechanically with grasping forceps. Cryotherapy was performed with a rigid cryoprobe (142 Cryo Unit; Spenbly Medical; Andover, UK) through a rigid bronchoscope. Liquid carbon dioxide was used as the cooling agent, which could reach a low temperature (⫺70°C). The metallic tip of the cryoprobe was placed on the tumor or the granulation tissue, and a freeze-thaw procedure was initiated, with each freeze-thaw cycle lasting about 30 s, and was carried out in three cycles at several points until the entire visible lesion had been frozen. Tissue necrosis usually occurs 8 to 15 days following the procedure. For the EBUS procedure (EU-M 20; Olympus), a 2.5-mm diameter, 20-MHz frequency radial mechanical transducer-type ultrasonic probe (UM-3R; Olympus, Tokyo, Japan) and a flexible balloon sheath equipped with a balloon at the tip (MH-246R; Olympus) were used. We introduced them through the 2.8-mm diameter channel of a flexible bronchoscope (BF-1T20; Olympus).
Results Clinical Summary Twelve patients who had a diagnosis of tracheobronchial tuberculosis were treated in our hospital. CHEST / 126 / 4 / OCTOBER, 2004
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Figure 1. Patient 1. Top left, A: rigid bronchoscopy revealed a dynamic collapse of the trachea. Top middle, B: bronchoscopic examination after placement of a Dumon Y-stent shows restored patency of the trachea. Top right, C: in this patient with variable tracheobronchial stenosis (flow-volume curve is represented by a dotted line), the descending expiratory limb showed a marked reduction of airflow. The flow-volume curve represented by the bold line returned to near normal by the placement of the stent. Bottom, D: EBUS imaging shows the interruption of the tracheal cartilage.
The clinical characteristics are presented in Table 1. Dyspnea was documented in 11 patients, and cough was documented in 1 patient. The sites of the lesions were as follows: left main bronchus, 8 patients; trachea, 4 patients; right main bronchus, 2 patients; and carina, 2 patients. Tracheobronchial stents were inserted after balloon dilatation in 6 of the 12 patients. Three patients received Dumon straight stents, and the remaining 3 patients received Dumon Y-stent. Patients 5 and 6 had previously undergone implantation of Ultraflex stents, but granulation tissue had grown through the mesh of the stent. In patients 1 to 4, EBUS was performed to evaluate the condition of the bronchial wall before stenting. Patients 5 and 6 required cryotherapy directed to granulation tissue at the edge of a Dumon stent. Patients 5 and 6 required APC to treat granulation tissue through the mesh. Patient 6 had damage to the mesh of the stent caused by metal fatigue from chronic coughing. Dumon stents were inserted through the previously implanted Ultraflex 1346
stents. Patients 7 through 11 were treated solely with balloon dilatation under local anesthesia. Patients 7 and 8, who had strictures of the right main bronchus and left main bronchus, showed decreased symptoms of dyspnea. The remaining three patients had shown little response and experienced early relapse. Patient 12 underwent a left pneumonectomy.
Case Reports Patient 1 was diagnosed with tracheobronchial tuberculosis. The patient had been treated with antituberculous medications for 3 months, and then was referred to our hospital because of persistent dyspnea on exertion. Bronchoscopy revealed a pinhole stenosis of the left main bronchus. We initially performed balloon dilatation of the left main bronchus, but the stenosis recurred rapidly. We therefore placed a Dumon stent in the left main bronchus. During the next 2 months, the patient complained of progressive dyspnea. We performed rigid bronchoscopy, which revealed migration of the stent, retained secretions within the stent, and dynamic collapse of the trachea. After the removal of the stent the carina was patent during positive-pressure ventilaBronchoscopy
tion but collapsed if positive-pressure ventilation was discontinued (Fig 1, top left, A). Tracheobronchoplastic surgery was impossible to perform as the affected segment, extending from the trachea into the main bronchus, was too long. Therefore, we placed a Dumon Y-stent to prevent airway compression during exhalation (Fig 1, top middle, B). In this case, with variable tracheobronchial stenosis, the flow-volume curve was represented by a dotted line with the descending expiratory limb showing marked reduction of airflow. Following stenting, the flow-volume curve, represented by a bold line in Figure 1, top right, C, returned to near normal. Before stenting, on visualizing the layers of the tracheal wall by EBUS, the normal horseshoeshaped cartilage could not be seen for a 4-cm length from the carina to the left main bronchus (Fig 1, bottom, D). Follow-up bronchoscopy confirmed that the airway was patent. The patient has remained asymptomatic for 4 years after stenting, during which period the stent has been replaced twice. Patient 2 presented with fever. A chest radiograph showed infiltrates in the left lung. Bronchial tuberculosis was diagnosed by bronchoscopy. After the completion of a course of antituberculous medication, she experienced three episodes of obstructive pneumonia. Bronchoscopy revealed a central pinhole stenosis of
the left main bronchus (Fig 2, top left, A). The patient was referred to our hospital but refused to undergo surgery, thus we placed a Dumon stent (diameter, 10 mm; length, 40 mm) after sequential dilatation of the airway with progressively larger balloons (Fig 2, top middle, B). One year later, we removed the stent, and the patient remained asymptomatic. Follow-up bronchoscopic examination confirmed patency of the left main bronchus (Fig 2, top right, C). The bronchial wall was thickened, and the bronchial cartilage appeared intact on EBUS imaging (Fig 2, bottom left, D). In this patient with bronchial stenosis, the decreased expiratory flow-volume curve improved following the placement of the stent. Stenting resulted in a marked rightward, nearly parallel shift of the descending expiratory limb of the flow-volume curve (Fig 2, bottom right, E). We successfully performed bronchoscopic interventions to prevent obstructive pneumonia. She has been well and asymptomatic for 2 years. Patient 3, who had been previously admitted to our hospital with tracheobronchial tuberculosis and had been receiving medication for 1 year, was readmitted with progressive dyspnea. Bronchoscopic examination revealed a slit-like stenosis of the left main bronchus. We inserted a Dumon stent following balloon dilatation after EBUS imaging showed a thickening of the
Figure 2. Patient 2. Top left, A: bronchoscopic examination shows annular scarring with stricture of the left main bronchus. Top middle, B: bronchoscopic examination after the placement of a Dumon stent shows correct positioning of the stent and restored patency of the left main bronchus. Top right, C: bronchoscopic examination after removal of a Dumon stent shows restored patency of the left main bronchus. Bottom right, D: EBUS imaging shows the thickening of the bronchial wall and intact bronchial cartilage. Bottom right, E: in this patient with a bronchial stenosis, the flow-volume curve (dotted line) showed decreased expiratory flow. Stenting resulted in a marked rightward, nearly parallel, shift of the descending expiratory limb of the flow-volume curve (bold line). www.chestjournal.org
CHEST / 126 / 4 / OCTOBER, 2004
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bronchial wall. Although the patient’s symptoms immediately improved, they recurred 2 months later. Bronchoscopic examination revealed an occlusion at the distal side of the stent due to granulation tissue formation. The stent was extracted, and granulation tissue regressed spontaneously. The left main bronchus was clearly patent when examined 1 month after the procedure, suggesting that the stent had accomplished effective dilatation. The patient has remained asymptomatic for 6 months. Patient 4 was admitted to our hospital with progressive dyspnea after 7 months of follow-up for tracheal tuberculosis. Bronchoscopic examination revealed slit-like tracheal stenosis (Fig 3, top left, A). To prevent suffocation, we inserted a Dumon Y-stent after balloon dilatation (Fig 3, top middle, B). After stenting, the FEV1 increased from 700 to 2,080 mL. In this patient with severe stenosis due to tracheal tuberculosis, the flow-volume curve showed marked reduction of the expiratory flow, with a plateau which is typically seen with fixed narrowing of the trachea. After placement of the Dumon Y-stent, the plateau was no longer apparent, and the flow increased (Fig 3, top right, C). The tracheal wall was thickened, and the horseshoe-shaped tracheal cartilage could not be seen for two rings according to the EBUS imagery (Fig 3, bottom left, D). We replaced the tracheal stent, and the patient has been well for 6 months since undergoing stenting. In patient 5, tracheobronchial tuberculosis had been diagnosed
at another institution 10 years previously. She had had a tracheal Dumon stent for 8 years. It was then removed because of granulation tissue formation at the stent edges. The patient had subsequently undergone implantation of Ultraflex nitinol stents in the trachea and right main bronchus at the same institution. The patient had required laser photoresection ⬎ 40 times in 2 years to remove granulation tissue. The patient was referred to our hospital in acute respiratory distress for emergency treatment. The airway had become extremely narrowed by granulation tissue ingrowth through the mesh of the stent (Fig 4, top left, A, and top right, B). We first resected some granulation tissue by APC, and then reamed it mechanically using the bevel of a rigid bronchoscope. At this point, we successfully removed the Ultraflex stent from the right main bronchus using rigid forceps. This stent had unraveled and was extracted completely. The tracheal stent remained in situ. A long Dumon Y-stent was placed within the tracheal Ultraflex nitinol stent after balloon dilatation (Fig 4, bottom left, C, and bottom right, D). The airway was clearly patent for 1 year after the procedure, when the patient complained of progressive dyspnea. Bronchoscopic examination revealed granulation tissue at the edge of the Dumon stent, and cryotherapy was performed to freeze it. The patient returned home in good health and has had no need of further treatment for 9 months. Patient 6 was admitted to our hospital with tracheal tubercu-
Figure 3. Patient 4. Top left, A: bronchoscopic examination shows a slit-like tracheal stenosis. Top middle, B: bronchoscopic examination shows a re-establishment of tracheal patency after the placement of a Dumon Y-stent. Top right, C: in the prestenting flow-volume curve (dotted line), an expiratory plateau, which is typically seen with supracarinal fixed airway stenosis, is clear. Following stenting, the expiratory peak flow showed a sharp increase (bold line). Bottom, D: EBUS imaging shows an interruption of the cartilage of the trachea and a thickening of the tracheal wall. 1348
Bronchoscopy
Figure 4. Patient 5. Top left, A: rigid bronchoscopy shows stenosis of the trachea caused by granulation tissue protruding through the mesh of an Ultraflex stent. Top right, B: coronal plane chest CT scan imagery obtained before the placement of a Dumon Y-stent shows an irregular intraluminal narrowing of the trachea due to granulation tissue growing through the mesh of an Ultraflex stent. Bottom left, C: rigid bronchoscopy shows the re-establishment of tracheal patency after the placement of a Dumon Y-stent. Bottom right, D: coronal plane chest CT scan image shows wide patency of the trachea after the placement of a Dumon Y-stent within the Ultraflex stent. Cryotherapy was performed to freeze granulation tissue at the edge of the Dumon stent.
losis complicated by severe tracheal stenosis and a tracheoesophageal fistula, and was close to asphyxiation (Fig 5, top left, A). We inserted a covered Ultraflex stent to seal the fistula and kept the airway patency by means of a percutaneous cardiopulmonary support (Fig 5, top right, B). The patient then was treated with antituberculous medications for 1 year. Five months after completing the medication regimen, the patient complained of dyspnea. Bronchoscopic examination revealed deterioration of the stent from metal fatigue caused by repeated coughing, as well as granulation tissue formation at the edge of stent (Fig 5, bottom left, C). Since the symptoms had progressively worsened, we inserted a Dumon stent within the covered Ultraflex stent after resection of the granulation tissue by means of APC and cryotherapy (Fig 5, bottom right, D). One year after undergoing this stenting, the patient is asymptomatic. Patient 12 was treated with antituberculous medications for 9 months, but she repeatedly developed obstructive pneumonia. Bronchoscopy revealed an almost complete obstruction of the left www.chestjournal.org
main bronchus. We could not perform balloon dilatation, because the left main bronchus was too narrow to pass the guidewire through. Since the stenotic area was too long to allow bronchoplasty, we performed a left pneumonectomy. Nine years after surgery, the patient is in good health.
Discussion Interventional bronchoscopy is an alternative treatment strategy to surgical resection in the management of stenosis resulting from tracheobronchial tuberculosis.1,2 Basically, stenting should be performed after balloon dilatation when the patients prove to be smear-negative for tuberculosis. Because stent-related complications are observed frequently CHEST / 126 / 4 / OCTOBER, 2004
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Figure 5. Patient 6. Top left, A: a bronchoscopic examination shows the pinhole stenosis of the trachea (black arrow) and the fistula to the esophagus (white arrow). Top right, B: bronchoscopic examination shows the trachea to be patent after the implantation of a covered Ultraflex stent. Bottom left, C: 17 months after the implantation of a covered Ultraflex stent, bronchoscopic examination revealed the deterioration of the stent (black arrow) from metal fatigue caused by repeated coughing, as well as granulation tissue formation at the edge of the stent (white arrow). Bottom right, D: bronchoscopic examination shows the re-establishment of tracheal patency after the placement of a Dumon stent within the covered Ultraflex stent.
in patients with benign stenosis caused by tracheobronchial tuberculosis, a removable stent should be selected. Thus, the Dumon stent is particularly suitable for patients with tuberculous tracheobronchial stenosis, and in our series it caused fewer complications than an expandable metallic stent. We succeeded in identifying the nature of the stenosis caused by tracheobronchial tuberculosis using serial flow-volume curves (ie, whether it was due to fixed narrowing or to dynamic collapse). EBUS imaging was useful in making a diagnosis of cartilaginous tracheobronchomalacia and in aiding the decision as to whether or not a stent was needed. In this study, we used EBUS imaging to evaluate the condition of tracheobronchial cartilage, which is important in assessing the tracheobronchial wall before the place1350
ment of a stent. To the best of our knowledge, this is the largest series of tuberculous tracheobronchial stenoses treated with interventional bronchoscopy and the first report using EBUS imaging to demonstrate the destruction of tracheobronchial cartilage due to tracheobronchial tuberculosis. Balloon dilatation for tracheobronchial stenosis was first described by Cohen et al,11 and Nakamura et al16 used this technique to treat tuberculous tracheobronchial stenosis. Balloon dilatation for tuberculous tracheobronchial stenosis is usually straightforward and minimally invasive, and can be performed under local anesthesia. It is particularly appropriate for annular cicatricial stenosis, since the balloon dilates the stenotic bronchus by expanding radially. This approach is the initial treatment of choice for tracheobronchial stenoBronchoscopy
sis, but early restenosis occurs in many cases. Ferretti et al,17 reported their experience in treating noninflammatory bronchial stenosis by balloon dilatation, achieving clinical success in 6 of 19 patients (32%). Lee et al,18 estimated that the overall success rate was about 30% after balloon dilatation. In our study, only two of five patients (40%) have had successful results with balloon dilatation alone for long periods of time. Since we considered that balloon dilatation alone is not an adequate treatment for tuberculous tracheobronchial stenosis, we performed stenting immediately afterward. Under these conditions, there are three major indications for the placement of airway stents.19 The primary indication is to re-establish the patency of the central airways. The secondary indication is to support weakened cartilage in the presence of tracheobronchial malacia. Tracheobronchial malacia requires the continued support of a stent to prevent dynamic airway collapse. EBUS clearly imaged the destruction and disappearance of the cartilage layers in the tracheobronchial wall. The third indication is to seal the fistula resulting from damage to the airway due to tuberculous erosion. The Dumon stent is widely used, and is considered to be a “gold standard” because it is economical, readjustment is simple, and removal and replacement are always possible. Most stents are straight, which is a design that is not well-suited for lesions near the carina because they may migrate.20 With the Dumon Y-stent, which is designed for lesions of the carina, there are fewer problems with migration because of its shape.21 Nomori et al22 reported stenosis from granulation tissue at the edges of a Dumon stent placed to treat a tuberculous tracheobronchial stenosis. We performed cryotherapy to freeze edge granulation tissue successfully. More recently, a self-expandable stent made of the metallic alloy nitinol, the Ultraflex stent, has become widely used for the treatment of tracheobronchial stenosis due to malignant tumors. Ducic and Khalafi23 reported that the Ultraflex stent also relieved tracheal stenosis due to benign causes without complications. Jantz and Silvestri24 reported no granulation tissue formation with either the covered or uncovered Ultraflex stent in 16 patients, regardless of diagnosis. However, in the cases we examined, the airway had been narrowed by granulation tissue ingrowth through the mesh of the nitinol stent, requiring APC and debulking. Granulation tissue formation was sometimes seen at the edge of the covered Ultraflex stent. Ultraflex stents have caused fewer complications in tracheobronchial stenosis caused by tracheobronchial tuberculosis than other expandable metallic stent such as the Gianturco stent. Even if a stent is epithelialized, removal is www.chestjournal.org
possible by means of rigid bronchoscopy. However, removal was difficult. The dynamic properties of this stent may lead to its fracture due to metal fatigue with severe repeated coughing. Severe dyspnea caused by granulation tissue formation was immediately relieved by the placement of Dumon stents within the uncovered nitinol stents. In one patient with tracheobronchial malacia necessitating long-term placement of a Dumon Y-stent, the Y-stent was replaced twice within 4 years. The decision as to whether a patient with tracheobronchial tuberculosis is a better candidate for surgery or stent placement is very complex. Kato et al2 suggested that surgery should be the therapy of choice in patients who can tolerate it. A stent should be placed only if the patient is definitely inoperable. In our cases of stenosis due to tracheobronchial tuberculosis, only one patient with complete bronchial obstruction underwent a left pneumonectomy. Dilatation of the cicatricial stenosis was rarely longlasting, and stent placement was performed temporarily. Two patients were spared surgery by means of temporary stenting.25 Schmidt et al26 reported that the stents can be removed when inflammation has diminished and severe malacia is absent in cases of benign tracheobronchial stenosis. Diffuse tracheobronchial stenosis due to tuberculosis poses many problems. If a stent is decided on as the means of treatment, then the demerits of stent migration, granulation, retained secretions, and stent fracture must be considered. The stent may have to be removed and be replaced by a longer stent (eg, by a Y-stent). Therefore, the long Dumon Y-stent appears to be particularly good for treating diffuse tracheobronchial stenosis due to tuberculosis. ACKNOWLEDGMENT: The authors are indebted to Professor J. Patrck Barron of the International Medical Communications Center of Tokyo Medical University for his review of this manuscript.
References 1 Hsu H, Hsu W, Huang B, et al. Surgical treatment of endobronchial tuberculosis. Scand Cardiovasc J 1997; 31: 79 – 82 2 Kato R, Kakizaki T, Hangai N, et al. Bronchoplastic procedures for tuberculous bronchial stenosis. J Thorac Cardiovasc Surg 1993; 106:1118 –1121 3 Seijo LM, Sterman DH. Interventional pulmonology. N Engl J Med 2001; 344:740 –749 4 Metha AC, Harris RJ, De Boer GE. Endoscopic management of benign airway stenosis. Clin Chest Med 1995; 16:401– 413 5 Beamis JF Jr., Shapshay SM, Setzer S, et al. Teaching models for Nd:YAG laser bronchoscopy. Chest 1989; 95:1316 –1318 6 Dumon JF. A dedicated tracheobronchial stent. Chest 1990; 97:328 –332 7 Miyazawa T, Arita K. Airway stenting in Japan. Respirology 1998; 3:229 –234 CHEST / 126 / 4 / OCTOBER, 2004
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8 Becker HD. Stenting of the central airways. J Bronchol 1995; 2:98 –106 9 Cavaliere S, Foccoli P, Farina PL. Nd-YAG laser bronchoscopy: a five-year experience with 1936 applications in 1,000 patients. Chest 1988; 94:15–21 10 Morice RC, Ece T, Ece F, et al. Endobronchial argon plasma coagulation for treatment of hemoptysis and neoplastic airway obstruction. Chest 2001; 119:781–787 11 Cohen MD, Weber TR, Rao CC. Balloon dilatation of tracheal and bronchial stenosis. AJR Am J Roentgenol 1984; 142:477– 478 12 Mathur PN, Wolf KM, Busk MF, et al. Fiberoptic bronchoscopic cryotherapy in the management of tracheobronchial obstruction. Chest 1996; 110:718 –723 13 Kurimoto N, Murayama M, Yoshioka S, et al. Assessment of usefulness of endobronchial ultrasonography in determination of depth of tracheobronchial tumor invasion. Chest 1999; 115:1500 –1506 14 Miyazawa T, Yamakido M, Ikeda S, et al. Implantation of Ultraflex nitinol stents in malignant tracheobronchial stenoses. Chest 2000; 118:959 –965 15 Miyazu Y, Miyazawa T, Kurimoto N, et al. Endobronchial ultrasonography in the assessment of centrally located earlystage lung cancer before photodynamic therapy. Am J Respir Crit Care Med 2002; 165:832– 837 16 Nakamura K, Terada N, Ohi M, et al. Tuberculous bronchial stenosis: treatment with balloon bronchoplasty. AJR Am J Roentgenol 1991; 157:1187–1188 17 Ferretti G, Jouvan FB, Thony F, et al. Benign noninflamma-
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tory bronchial stenosis: treatment with balloon dilatation. Radiology 1995; 196:831– 834 Lee KW, Im JG, Han JK, et al. Tuberculous stenosis of the left main bronchus: results of treatment with balloons and metallic stents. J Vasc Interv Radiol 1999; 10:352–358 Freitag L. Tracheobronchial stents. In: Bolliger CT, Mathur P, eds. Interventional bronchoscopy. Basel, Switzerland: Karger, 2000; 171–186 Wan Innes YP, Lee TW, et al. Tracheobronchial stenting for tuberculous airway stenosis. Chest 2002; 122:370 –374 Dumon JF, Dumon MC. Dumon-Novatech Y-stents: a fouryear experience with 50 tracheobronchial tumors involving the carina. J Bronchol 2000; 7:26 –32 Nomori H, Horio H, Suemasu K. Granulation stenosis caused by a dumon stent placed for endobronchial tuberculous stenosis. Surg Laparosc Endosc Percutan Tech 2000; 10: 41– 43 Ducic Y, Khalafi RS. Use of endoscopically placed expandable nitinol stents in the treatment of tracheal stenosis. Laryngoscope 1999; 109:1130 –1133 Jantz MA, Silvestri GA. Silicone stents versus metal stents for management of benign tracheobronchial disease. J Bronchol 2000; 7:177–183 Witt C, Dinges S, Shmidt B, et al. Temporary tracheobronchial stenting in malignant stenoses. Eur J Cancer 1997; 3:204 –208 Schmidt B, Olze H, Borges A, et al. Endotracheal balloon dilatation and stent implantation in benign stenoses. Ann Thorac Surg 2001; 71:1630 –1634
Bronchoscopy
Study objectives: To assess the efficacy and complications of interventional bronchoscopic techniques in treating airway stenosis due to tracheobronchial tuberculosis. Design: Case series. Setting: Respiratory care centers at two tertiary care referral teaching hospitals in Japan, Hiroshima City Hospital and Okayama Red Cross Hospital. Patients and interventions: A total of 30 patients were admitted to the hospital with a diagnosis of tracheobronchial tuberculosis between January 1991 and January 2002. Of those 11 patients received interventional bronchoscopy, including stent placement, laser photoresection, argon plasma coagulation (APC), balloon dilatation, cryotherapy, and endobronchial ultrasonography (EBUS). One patient with complete bronchial obstruction underwent a left pneumonectomy. Results: Six patients underwent stent placement after balloon dilatation, while the remaining five patients underwent only balloon dilatation. In six patients, Dumon stents were successfully placed to reestablish the patency of the central airways. Two patients first had Ultraflex stents implanted but had problems with granulation tissue formation and stent deterioration caused by metal fatigue due to chronic coughing. Dumon stents then were placed within the Ultraflex stents after the patient had received treatment with APC and mechanical reaming using the bevel of a rigid bronchoscope. In four patients, EBUS images demonstrated the destruction of bronchial cartilage or the thickening of the bronchial wall. The main complications of Dumon stents are migration and granulation tissue formation, necessitating stent removal, or replacement, and the application of cryotherapy to the granuloma at the edge of the stent. Conclusion: Interventional bronchoscopy should be considered feasible for management of tuberculous tracheobronchial stenosis. Dumon stents seem to be appropriate, since removal or replacement is always possible. Ultraflex stents should not be used in these circumstances because removal is difficult and their long-term safety is uncertain. EBUS could provide useful information in evaluating the condition of the airway wall in cases of tracheobronchial tuberculosis with potential for bronchoscopic intervention. (CHEST 2004; 126:1344 –1352) Key words: balloon dilatation; endobronchial ultrasonography; stent placement; tracheobronchial stenosis Abbreviations: APC ⫽ argon plasma coagulation; EBUS ⫽ endobronchial ultrasonography
tracheobronchial stenosis is a serious T uberculous clinical problem because it can cause obstructive pneumonia and dyspnea on exertion. Surgical resection and bronchoplastic reconstruction has long been the standard treatment.1,2 More recently, a variety of interventional bronchoscopic techniques has been developed,3–5 including stent placement,6 – 8 laser photoresection,9 argon plasma coagulation (APC),10 1344
balloon dilatation,11 cryotherapy12 and endobronchial ultrasonography (EBUS).13 The development and refinement of various airway stents and increased experience have broadened the indications for these procedures. We reported previously7,14 that stenting has become a valuable new therapeutic strategy for patients with malignant or benign tracheobronchial stenosis. However, the indications for Bronchoscopy
Table 1—Clinical Features, Interventions, and Outcomes in Tuberculous Tracheobronchial Stenosis* Patient/Sex/Age, yr 1/F/59 2/F/29 3/M/59 4/M/65 5/F/48 6/F/56 7/F/77 8/F/18 9/F/38 10/F/53 11/F/31 12/F/19
Symptoms
Sites of Lesions
Intervention
Outcome
Dyspnea Dyspnea Dyspnea Dyspnea Dyspnea Dyspnea Dyspnea Dyspnea Dyspnea Dyspnea Cough Dyspnea
Trachea, carina, LMB LMB LMB Trachea Trachea, carina, RMB Trachea RMB LMB LMB LMB LMB LMB
Balloon, Dumon Y, EBUS Balloon, Dumon, EBUS Balloon, Dumon, EBUS Balloon, Dumon Y, EBUS Balloon, APC, cryotherapy, Ultraflex, Dumon Y Balloon, APC, cryotherapy, Ultraflex, Dumon Balloon Balloon Balloon Balloon Balloon Left pneumonectomy
Improved Improved Improved Improved Improved Improved Improved Improved Unchanged Unchanged Unchanged Improved
*RMB ⫽ right main bronchus; LMB ⫽ left main bronchus; F ⫽ female; M ⫽ male.
stenting in patients with tuberculous tracheobronchial stenosis are difficult to understand, and prognosis is unclear. We carefully evaluated what might be the best interventional strategy in this complex situation. EBUS has been used in recent years to evaluate the individual layers of the bronchial wall. In our previous study,13,15 the images produced by EBUS correlated with histologic results. The third layer (hyperechoic) is the marginal echo on the inner side of the bronchial cartilage, and the fourth layer (hypoechoic) is the bronchial cartilage. Thus, we considered that EBUS might provide useful information for a planned bronchoscopic intervention. This report highlights patients with tracheobronchial tuberculosis in whom diagnosis and treatment were made by various methods of interventional bronchoscopy, including EBUS and stent placement for stenoses. Patients and Methods From January 1991 to January 2002, 30 patients with tracheobronchial tuberculosis were admitted to our institutions. Among these patients, treatment with antituberculous medication resulted in 18 patients recovering and remaining asymptomatic. *From the Department of Pulmonary Medicine (Drs. Iwamoto, Miyazawa, Miyazu, and Ishida), Hiroshima City Hospital, Hiroshima, Japan; the Department of Surgery (Dr. Kurimoto), Hiroshima National Hospital, Higashi-Hiroshima, Japan; and the Department of Pulmonary Medicine (Drs. Matsuo and Watanabe), Okayama Red Cross Hospital, Okayama, Japan. Received September 18, 2003; revision accepted April 22, 2004. Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (e-mail: [email protected]). Correspondence to: Teruomi Miyazawa, MD, PhD, FCCP, Director, Department of Pulmonary Medicine, Hiroshima City Hospital, 7–33 Naka-Ku, Moto-machi, Hiroshima City, Hiroshima Prefecture, 730-8518 Japan; e-mail: miyazawt@ carrot.ocn.ne.jp www.chestjournal.org
However, 12 patients developed dyspnea, severe cough, and repeated obstructive pneumonia due to tracheobronchial stenosis. These 12 patients were considered to be suitable candidates for intervention (bronchoscopy, 11 patients; pneumonectomy, 1 patient). The clinical characteristics are presented in Table 1. All patients were examined by flexible bronchoscopy (BF200; Olympus; Tokyo, Japan). The sites of bronchial lesions in each patient are also shown in Table 1. Before bronchoscopic intervention, written informed consent was obtained from all patients. After balloon dilatation (Accent Balloon Angioplasty Catheters; Cook Inc; Bloomington, IN) as well as gentle dilatation with the bevel of a rigid bronchoscope (Efer; La Ciolat, France) under general anesthesia and fluoroscopic visualization, the Dumon stent (Novatech; Aubagne, France) and the Ultraflex stent (Boston Scientific; Natick, MA) were placed according to the technique recommended by their originators.6,8 Endobronchial APC (APC; Erbe USA; Marietta, GA) was performed via a flexible bronchoscope (energy applied, 30 to 40 W; argon flow, 1.6 L/min). A monopolar APC probe, 220 cm in length and 2.3 mm in diameter, was inserted through the working channel of the bronchoscope. The target tissue was visualized endoscopically and then coagulated. The coagulated tissue then was removed mechanically with grasping forceps. Cryotherapy was performed with a rigid cryoprobe (142 Cryo Unit; Spenbly Medical; Andover, UK) through a rigid bronchoscope. Liquid carbon dioxide was used as the cooling agent, which could reach a low temperature (⫺70°C). The metallic tip of the cryoprobe was placed on the tumor or the granulation tissue, and a freeze-thaw procedure was initiated, with each freeze-thaw cycle lasting about 30 s, and was carried out in three cycles at several points until the entire visible lesion had been frozen. Tissue necrosis usually occurs 8 to 15 days following the procedure. For the EBUS procedure (EU-M 20; Olympus), a 2.5-mm diameter, 20-MHz frequency radial mechanical transducer-type ultrasonic probe (UM-3R; Olympus, Tokyo, Japan) and a flexible balloon sheath equipped with a balloon at the tip (MH-246R; Olympus) were used. We introduced them through the 2.8-mm diameter channel of a flexible bronchoscope (BF-1T20; Olympus).
Results Clinical Summary Twelve patients who had a diagnosis of tracheobronchial tuberculosis were treated in our hospital. CHEST / 126 / 4 / OCTOBER, 2004
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Figure 1. Patient 1. Top left, A: rigid bronchoscopy revealed a dynamic collapse of the trachea. Top middle, B: bronchoscopic examination after placement of a Dumon Y-stent shows restored patency of the trachea. Top right, C: in this patient with variable tracheobronchial stenosis (flow-volume curve is represented by a dotted line), the descending expiratory limb showed a marked reduction of airflow. The flow-volume curve represented by the bold line returned to near normal by the placement of the stent. Bottom, D: EBUS imaging shows the interruption of the tracheal cartilage.
The clinical characteristics are presented in Table 1. Dyspnea was documented in 11 patients, and cough was documented in 1 patient. The sites of the lesions were as follows: left main bronchus, 8 patients; trachea, 4 patients; right main bronchus, 2 patients; and carina, 2 patients. Tracheobronchial stents were inserted after balloon dilatation in 6 of the 12 patients. Three patients received Dumon straight stents, and the remaining 3 patients received Dumon Y-stent. Patients 5 and 6 had previously undergone implantation of Ultraflex stents, but granulation tissue had grown through the mesh of the stent. In patients 1 to 4, EBUS was performed to evaluate the condition of the bronchial wall before stenting. Patients 5 and 6 required cryotherapy directed to granulation tissue at the edge of a Dumon stent. Patients 5 and 6 required APC to treat granulation tissue through the mesh. Patient 6 had damage to the mesh of the stent caused by metal fatigue from chronic coughing. Dumon stents were inserted through the previously implanted Ultraflex 1346
stents. Patients 7 through 11 were treated solely with balloon dilatation under local anesthesia. Patients 7 and 8, who had strictures of the right main bronchus and left main bronchus, showed decreased symptoms of dyspnea. The remaining three patients had shown little response and experienced early relapse. Patient 12 underwent a left pneumonectomy.
Case Reports Patient 1 was diagnosed with tracheobronchial tuberculosis. The patient had been treated with antituberculous medications for 3 months, and then was referred to our hospital because of persistent dyspnea on exertion. Bronchoscopy revealed a pinhole stenosis of the left main bronchus. We initially performed balloon dilatation of the left main bronchus, but the stenosis recurred rapidly. We therefore placed a Dumon stent in the left main bronchus. During the next 2 months, the patient complained of progressive dyspnea. We performed rigid bronchoscopy, which revealed migration of the stent, retained secretions within the stent, and dynamic collapse of the trachea. After the removal of the stent the carina was patent during positive-pressure ventilaBronchoscopy
tion but collapsed if positive-pressure ventilation was discontinued (Fig 1, top left, A). Tracheobronchoplastic surgery was impossible to perform as the affected segment, extending from the trachea into the main bronchus, was too long. Therefore, we placed a Dumon Y-stent to prevent airway compression during exhalation (Fig 1, top middle, B). In this case, with variable tracheobronchial stenosis, the flow-volume curve was represented by a dotted line with the descending expiratory limb showing marked reduction of airflow. Following stenting, the flow-volume curve, represented by a bold line in Figure 1, top right, C, returned to near normal. Before stenting, on visualizing the layers of the tracheal wall by EBUS, the normal horseshoeshaped cartilage could not be seen for a 4-cm length from the carina to the left main bronchus (Fig 1, bottom, D). Follow-up bronchoscopy confirmed that the airway was patent. The patient has remained asymptomatic for 4 years after stenting, during which period the stent has been replaced twice. Patient 2 presented with fever. A chest radiograph showed infiltrates in the left lung. Bronchial tuberculosis was diagnosed by bronchoscopy. After the completion of a course of antituberculous medication, she experienced three episodes of obstructive pneumonia. Bronchoscopy revealed a central pinhole stenosis of
the left main bronchus (Fig 2, top left, A). The patient was referred to our hospital but refused to undergo surgery, thus we placed a Dumon stent (diameter, 10 mm; length, 40 mm) after sequential dilatation of the airway with progressively larger balloons (Fig 2, top middle, B). One year later, we removed the stent, and the patient remained asymptomatic. Follow-up bronchoscopic examination confirmed patency of the left main bronchus (Fig 2, top right, C). The bronchial wall was thickened, and the bronchial cartilage appeared intact on EBUS imaging (Fig 2, bottom left, D). In this patient with bronchial stenosis, the decreased expiratory flow-volume curve improved following the placement of the stent. Stenting resulted in a marked rightward, nearly parallel shift of the descending expiratory limb of the flow-volume curve (Fig 2, bottom right, E). We successfully performed bronchoscopic interventions to prevent obstructive pneumonia. She has been well and asymptomatic for 2 years. Patient 3, who had been previously admitted to our hospital with tracheobronchial tuberculosis and had been receiving medication for 1 year, was readmitted with progressive dyspnea. Bronchoscopic examination revealed a slit-like stenosis of the left main bronchus. We inserted a Dumon stent following balloon dilatation after EBUS imaging showed a thickening of the
Figure 2. Patient 2. Top left, A: bronchoscopic examination shows annular scarring with stricture of the left main bronchus. Top middle, B: bronchoscopic examination after the placement of a Dumon stent shows correct positioning of the stent and restored patency of the left main bronchus. Top right, C: bronchoscopic examination after removal of a Dumon stent shows restored patency of the left main bronchus. Bottom right, D: EBUS imaging shows the thickening of the bronchial wall and intact bronchial cartilage. Bottom right, E: in this patient with a bronchial stenosis, the flow-volume curve (dotted line) showed decreased expiratory flow. Stenting resulted in a marked rightward, nearly parallel, shift of the descending expiratory limb of the flow-volume curve (bold line). www.chestjournal.org
CHEST / 126 / 4 / OCTOBER, 2004
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bronchial wall. Although the patient’s symptoms immediately improved, they recurred 2 months later. Bronchoscopic examination revealed an occlusion at the distal side of the stent due to granulation tissue formation. The stent was extracted, and granulation tissue regressed spontaneously. The left main bronchus was clearly patent when examined 1 month after the procedure, suggesting that the stent had accomplished effective dilatation. The patient has remained asymptomatic for 6 months. Patient 4 was admitted to our hospital with progressive dyspnea after 7 months of follow-up for tracheal tuberculosis. Bronchoscopic examination revealed slit-like tracheal stenosis (Fig 3, top left, A). To prevent suffocation, we inserted a Dumon Y-stent after balloon dilatation (Fig 3, top middle, B). After stenting, the FEV1 increased from 700 to 2,080 mL. In this patient with severe stenosis due to tracheal tuberculosis, the flow-volume curve showed marked reduction of the expiratory flow, with a plateau which is typically seen with fixed narrowing of the trachea. After placement of the Dumon Y-stent, the plateau was no longer apparent, and the flow increased (Fig 3, top right, C). The tracheal wall was thickened, and the horseshoe-shaped tracheal cartilage could not be seen for two rings according to the EBUS imagery (Fig 3, bottom left, D). We replaced the tracheal stent, and the patient has been well for 6 months since undergoing stenting. In patient 5, tracheobronchial tuberculosis had been diagnosed
at another institution 10 years previously. She had had a tracheal Dumon stent for 8 years. It was then removed because of granulation tissue formation at the stent edges. The patient had subsequently undergone implantation of Ultraflex nitinol stents in the trachea and right main bronchus at the same institution. The patient had required laser photoresection ⬎ 40 times in 2 years to remove granulation tissue. The patient was referred to our hospital in acute respiratory distress for emergency treatment. The airway had become extremely narrowed by granulation tissue ingrowth through the mesh of the stent (Fig 4, top left, A, and top right, B). We first resected some granulation tissue by APC, and then reamed it mechanically using the bevel of a rigid bronchoscope. At this point, we successfully removed the Ultraflex stent from the right main bronchus using rigid forceps. This stent had unraveled and was extracted completely. The tracheal stent remained in situ. A long Dumon Y-stent was placed within the tracheal Ultraflex nitinol stent after balloon dilatation (Fig 4, bottom left, C, and bottom right, D). The airway was clearly patent for 1 year after the procedure, when the patient complained of progressive dyspnea. Bronchoscopic examination revealed granulation tissue at the edge of the Dumon stent, and cryotherapy was performed to freeze it. The patient returned home in good health and has had no need of further treatment for 9 months. Patient 6 was admitted to our hospital with tracheal tubercu-
Figure 3. Patient 4. Top left, A: bronchoscopic examination shows a slit-like tracheal stenosis. Top middle, B: bronchoscopic examination shows a re-establishment of tracheal patency after the placement of a Dumon Y-stent. Top right, C: in the prestenting flow-volume curve (dotted line), an expiratory plateau, which is typically seen with supracarinal fixed airway stenosis, is clear. Following stenting, the expiratory peak flow showed a sharp increase (bold line). Bottom, D: EBUS imaging shows an interruption of the cartilage of the trachea and a thickening of the tracheal wall. 1348
Bronchoscopy
Figure 4. Patient 5. Top left, A: rigid bronchoscopy shows stenosis of the trachea caused by granulation tissue protruding through the mesh of an Ultraflex stent. Top right, B: coronal plane chest CT scan imagery obtained before the placement of a Dumon Y-stent shows an irregular intraluminal narrowing of the trachea due to granulation tissue growing through the mesh of an Ultraflex stent. Bottom left, C: rigid bronchoscopy shows the re-establishment of tracheal patency after the placement of a Dumon Y-stent. Bottom right, D: coronal plane chest CT scan image shows wide patency of the trachea after the placement of a Dumon Y-stent within the Ultraflex stent. Cryotherapy was performed to freeze granulation tissue at the edge of the Dumon stent.
losis complicated by severe tracheal stenosis and a tracheoesophageal fistula, and was close to asphyxiation (Fig 5, top left, A). We inserted a covered Ultraflex stent to seal the fistula and kept the airway patency by means of a percutaneous cardiopulmonary support (Fig 5, top right, B). The patient then was treated with antituberculous medications for 1 year. Five months after completing the medication regimen, the patient complained of dyspnea. Bronchoscopic examination revealed deterioration of the stent from metal fatigue caused by repeated coughing, as well as granulation tissue formation at the edge of stent (Fig 5, bottom left, C). Since the symptoms had progressively worsened, we inserted a Dumon stent within the covered Ultraflex stent after resection of the granulation tissue by means of APC and cryotherapy (Fig 5, bottom right, D). One year after undergoing this stenting, the patient is asymptomatic. Patient 12 was treated with antituberculous medications for 9 months, but she repeatedly developed obstructive pneumonia. Bronchoscopy revealed an almost complete obstruction of the left www.chestjournal.org
main bronchus. We could not perform balloon dilatation, because the left main bronchus was too narrow to pass the guidewire through. Since the stenotic area was too long to allow bronchoplasty, we performed a left pneumonectomy. Nine years after surgery, the patient is in good health.
Discussion Interventional bronchoscopy is an alternative treatment strategy to surgical resection in the management of stenosis resulting from tracheobronchial tuberculosis.1,2 Basically, stenting should be performed after balloon dilatation when the patients prove to be smear-negative for tuberculosis. Because stent-related complications are observed frequently CHEST / 126 / 4 / OCTOBER, 2004
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Figure 5. Patient 6. Top left, A: a bronchoscopic examination shows the pinhole stenosis of the trachea (black arrow) and the fistula to the esophagus (white arrow). Top right, B: bronchoscopic examination shows the trachea to be patent after the implantation of a covered Ultraflex stent. Bottom left, C: 17 months after the implantation of a covered Ultraflex stent, bronchoscopic examination revealed the deterioration of the stent (black arrow) from metal fatigue caused by repeated coughing, as well as granulation tissue formation at the edge of the stent (white arrow). Bottom right, D: bronchoscopic examination shows the re-establishment of tracheal patency after the placement of a Dumon stent within the covered Ultraflex stent.
in patients with benign stenosis caused by tracheobronchial tuberculosis, a removable stent should be selected. Thus, the Dumon stent is particularly suitable for patients with tuberculous tracheobronchial stenosis, and in our series it caused fewer complications than an expandable metallic stent. We succeeded in identifying the nature of the stenosis caused by tracheobronchial tuberculosis using serial flow-volume curves (ie, whether it was due to fixed narrowing or to dynamic collapse). EBUS imaging was useful in making a diagnosis of cartilaginous tracheobronchomalacia and in aiding the decision as to whether or not a stent was needed. In this study, we used EBUS imaging to evaluate the condition of tracheobronchial cartilage, which is important in assessing the tracheobronchial wall before the place1350
ment of a stent. To the best of our knowledge, this is the largest series of tuberculous tracheobronchial stenoses treated with interventional bronchoscopy and the first report using EBUS imaging to demonstrate the destruction of tracheobronchial cartilage due to tracheobronchial tuberculosis. Balloon dilatation for tracheobronchial stenosis was first described by Cohen et al,11 and Nakamura et al16 used this technique to treat tuberculous tracheobronchial stenosis. Balloon dilatation for tuberculous tracheobronchial stenosis is usually straightforward and minimally invasive, and can be performed under local anesthesia. It is particularly appropriate for annular cicatricial stenosis, since the balloon dilates the stenotic bronchus by expanding radially. This approach is the initial treatment of choice for tracheobronchial stenoBronchoscopy
sis, but early restenosis occurs in many cases. Ferretti et al,17 reported their experience in treating noninflammatory bronchial stenosis by balloon dilatation, achieving clinical success in 6 of 19 patients (32%). Lee et al,18 estimated that the overall success rate was about 30% after balloon dilatation. In our study, only two of five patients (40%) have had successful results with balloon dilatation alone for long periods of time. Since we considered that balloon dilatation alone is not an adequate treatment for tuberculous tracheobronchial stenosis, we performed stenting immediately afterward. Under these conditions, there are three major indications for the placement of airway stents.19 The primary indication is to re-establish the patency of the central airways. The secondary indication is to support weakened cartilage in the presence of tracheobronchial malacia. Tracheobronchial malacia requires the continued support of a stent to prevent dynamic airway collapse. EBUS clearly imaged the destruction and disappearance of the cartilage layers in the tracheobronchial wall. The third indication is to seal the fistula resulting from damage to the airway due to tuberculous erosion. The Dumon stent is widely used, and is considered to be a “gold standard” because it is economical, readjustment is simple, and removal and replacement are always possible. Most stents are straight, which is a design that is not well-suited for lesions near the carina because they may migrate.20 With the Dumon Y-stent, which is designed for lesions of the carina, there are fewer problems with migration because of its shape.21 Nomori et al22 reported stenosis from granulation tissue at the edges of a Dumon stent placed to treat a tuberculous tracheobronchial stenosis. We performed cryotherapy to freeze edge granulation tissue successfully. More recently, a self-expandable stent made of the metallic alloy nitinol, the Ultraflex stent, has become widely used for the treatment of tracheobronchial stenosis due to malignant tumors. Ducic and Khalafi23 reported that the Ultraflex stent also relieved tracheal stenosis due to benign causes without complications. Jantz and Silvestri24 reported no granulation tissue formation with either the covered or uncovered Ultraflex stent in 16 patients, regardless of diagnosis. However, in the cases we examined, the airway had been narrowed by granulation tissue ingrowth through the mesh of the nitinol stent, requiring APC and debulking. Granulation tissue formation was sometimes seen at the edge of the covered Ultraflex stent. Ultraflex stents have caused fewer complications in tracheobronchial stenosis caused by tracheobronchial tuberculosis than other expandable metallic stent such as the Gianturco stent. Even if a stent is epithelialized, removal is www.chestjournal.org
possible by means of rigid bronchoscopy. However, removal was difficult. The dynamic properties of this stent may lead to its fracture due to metal fatigue with severe repeated coughing. Severe dyspnea caused by granulation tissue formation was immediately relieved by the placement of Dumon stents within the uncovered nitinol stents. In one patient with tracheobronchial malacia necessitating long-term placement of a Dumon Y-stent, the Y-stent was replaced twice within 4 years. The decision as to whether a patient with tracheobronchial tuberculosis is a better candidate for surgery or stent placement is very complex. Kato et al2 suggested that surgery should be the therapy of choice in patients who can tolerate it. A stent should be placed only if the patient is definitely inoperable. In our cases of stenosis due to tracheobronchial tuberculosis, only one patient with complete bronchial obstruction underwent a left pneumonectomy. Dilatation of the cicatricial stenosis was rarely longlasting, and stent placement was performed temporarily. Two patients were spared surgery by means of temporary stenting.25 Schmidt et al26 reported that the stents can be removed when inflammation has diminished and severe malacia is absent in cases of benign tracheobronchial stenosis. Diffuse tracheobronchial stenosis due to tuberculosis poses many problems. If a stent is decided on as the means of treatment, then the demerits of stent migration, granulation, retained secretions, and stent fracture must be considered. The stent may have to be removed and be replaced by a longer stent (eg, by a Y-stent). Therefore, the long Dumon Y-stent appears to be particularly good for treating diffuse tracheobronchial stenosis due to tuberculosis. ACKNOWLEDGMENT: The authors are indebted to Professor J. Patrck Barron of the International Medical Communications Center of Tokyo Medical University for his review of this manuscript.
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