Airway Stenting for Patients With Benign Airway Disease and the Food and Drug Administration Advisory: A Call for Restraint

Abstract

Airway stenting has become a common technique for treating central airway obstruction (CAO) caused by a variety of malignant and benign diseases. The original stents used by Duvall and Bauer,1Duvall AJ Bauer W An endoscopically introducible T-tube for tracheal stenosis.Laryngoscope. 1977; 87: 2031-2037Crossref PubMed Scopus (24) Google Scholar Cooper et al,2Cooper JD Pearson FG Patterson GA et al.Use of silicone stents in the management of airway problems.Ann Thorac Surg. 1989; 47: 371-378Abstract Full Text PDF PubMed Scopus (175) Google Scholar and Dumon3Dumon JF A dedicated tracheobronchial stent.Chest. 1990; 97: 328-332Abstract Full Text Full Text PDF PubMed Scopus (557) Google Scholar were silastic and required general anesthesia and rigid bronchoscopy for placement. The advent of the Wallstent (Boston Scientific Corporation; Natick, MA) introduced a new generation of stents that were metallic, self-expanding, and easily deployable, the so-called self-expanding metal stent (SEMS). However, the ease of deployment came with a cost. Over time, the metallic stents integrate into the airway, leading to complications such as stent fracture, erosion into adjacent structures, mucous retention, and granulation tissue formation. This is especially true in patients with benign airway disease, whose life expectancy is not inherently limited by their primary disease and in whom the stents can exist for years. This point was highlighted by Stephens and Wood,4Stephens KE Wood DE Bronchoscopic management of central airway obstruction.J Thorac Cardiovasc Surg. 2000; 119: 289-296Abstract Full Text Full Text PDF PubMed Scopus (124) Google Scholar who found that the vast majority of all early and late deaths following airway procedures for patients with benign and malignant CAO occurred in the malignant group.Over the past 5 years, there has been an increase in the number of adverse events reported after the deployment of SEMS for benign airway disease. This apparent increase in metallic airway stent failures led the Food and Drug Administration (FDA) to publish an advisory on the use of metallic stents in patients with benign airway disease in 2005 (Fig 1).5Food and Drug Administration. FDA public health notification: complications from metallic tracheal stents in patients with benign airway disorders, 2005. Available at: www.fda.gov/cdrh/safety/072905-tracheal.html. Accessed January 15, 2007Google Scholar Despite the publishing of this advisory, there still are no consensus recommendations for the use of SEMS in patients with benign CAO. Many physicians who regularly treat patients with CAO have seen and managed complications of metallic stents placed for nonmalignant disease. Despite this fact, several studies6Saad CP Murthy S Krizmanich G et al.Self-expandable metallic airway stents and flexible bronchoscopy: long-term outcome analysis.Chest. 2003; 124: 1993-1999Abstract Full Text Full Text PDF PubMed Scopus (253) Google Scholar7Madden BP Loke TK Sheth AC Do expandable metallic airway stents have a role in the management of patients with benign tracheobronchial disease?.Ann Thorac Surg. 2006; 82: 274-278Abstract Full Text Full Text PDF PubMed Scopus (127) Google Scholar8Thornton RH Gordon RL Kerlan RK et al.Outcomes of tracheobronchial stent placement for benign disease.Radiology. 2006; 240: 273-282Crossref PubMed Scopus (71) Google Scholar have shown that SEMS can be used successfully in patients with benign CAO but with complication rates that approach 45%.Disastrous complications include erosion of stents into adjacent structures.9Shiraishi T Shirakusa T Ninomiya H et al.Penetration to the aortic wall by a metal airway stent. A successfully treated case with left pneumonectomy and aortic repair.J Cardiovasc Surg. 2005; 46: 473-475PubMed Google Scholar More commonly, stents can become colonized with bacteria, leading to increased mucous production and formation of granulation tissue. Noppen and colleagues10Noppen M Pierard D Meysman M et al.Bacterial colonization of central airways after stenting.Am J Respir Crit Care Med. 1999; 160: 672-677Crossref PubMed Scopus (90) Google Scholar reported an 80% incidence of bacterial colonization after airway stent placement in patients without evidence of colonization prior to stenting. Pathogens included pseudomonas, Staphylococcus aureus, Streptococcus pneumonia, and klebsiella.10Noppen M Pierard D Meysman M et al.Bacterial colonization of central airways after stenting.Am J Respir Crit Care Med. 1999; 160: 672-677Crossref PubMed Scopus (90) Google Scholar This is compared to a study11Noppen M Perrard D Meysman M et al.Absence of bacterial colonization of the airways after therapeutic rigid bronchoscopy without stenting.Eur Respir J. 2000; 16: 1147-1151Crossref PubMed Scopus (8) Google Scholar that showed a 20% decrease in the incidence of bacterial airway colonization in patients with airway obstruction following therapeutic rigid bronchoscopy without subsequent stent placement. Although bacterial colonization can occur also with silastic stents, the ability to remove these stents makes this issue less critical.While removal of granulation tissue in a stent can be achieved relatively easily with Nd-YAG laser, cryotherapy, or argon beam coagulation, complete removal of an endothelialized or infected incorporated stent may be necessary. This procedure is difficult and can be extremely hazardous to the patient.12Murthy S Gildea TR Mehta AC Removal of self-expanding metallic stents: is it possible?.Semin Respir Crit Care Med. 2004; 25: 381-385Crossref PubMed Scopus (33) Google Scholar Lunn et al13Lunn W Feller-Kopman D Wahidi M et al.Endoscopic removal of metallic airway stents.Chest. 2005; 127: 2106-2112Abstract Full Text Full Text PDF PubMed Scopus (118) Google Scholar reported on stent extractions in 30 patients, 20 of whom had benign airway disease, and found that 97% of the complications associated with the stent extraction occurred in the benign CAO group and included mucosal tears, retained stent fragments, and airway obstruction.All of the difficulties encountered in patients with long-term airway SEMS highlight the point that SEMS should be avoided whenever possible in patients with benign CAO, with exceptions for patients with inoperable disease or significant comorbidities that render them inoperable. Even in these patients, other therapies such as airway debridement or dilatation and the placement of removable stents should be considered prior to the placement of a SEMS. Therapeutic strategies in these patients are best dealt with in a multidisciplinary setting, where pulmonologists and surgeons, knowledgeable in airway diseases, can decide on the best therapy for the patient. Postsurgical CAO involving anastomotic strictures following lung transplantation or tracheal resection is best dealt with at institutions that are used to dealing with these patients,14Mughal MM Gildea TR Murthy S et al.Short-term deployment of self-expanding metallic stents facilitates healing of bronchial dehiscence.Am J Respir Crit Care Med. 2005; 172: 768-771Crossref PubMed Scopus (113) Google Scholar who may require frequent bronchoscopies, stent changes, or other surgical procedures to treat the involved airway.The FDA advisory highlighted an ongoing concern held by many pulmonologists and surgeons: stents are being employed in patients with benign airway obstruction without consideration for other therapeutic modalities and without consideration of the possible long-term complications inherent with the use of SEMS. The members of the American College of Chest Physicians (ACCP) Interventional and Chest Diagnostics Network Steering Committee fully support the FDA warning. Although there are no universally agreed-on guidelines defining proficiency for stent placement, all physicians who utilize endotracheal/bronchial therapies should be familiar with the ACCP and the American Thoracic Society/European Respiratory Society guidelines regarding recommended provider training requirements, clinical experience, and competency.15Ernst A Silvestri GA Johnstone D Interventional pulmonary procedures: guidelines from the American College of Chest Physicians.Chest. 2003; 123: 1693-1717Abstract Full Text Full Text PDF PubMed Scopus (522) Google Scholar16Bolliger CT Mathur PN Beamis JF et al.ERS/ATS statement on interventional pulmonology: European Respiratory Society/American Thoracic Society.Eur Respir J. 2002; 19: 356-373Crossref PubMed Scopus (481) Google Scholar Furthermore, all physicians who perform airway stenting should report all adverse device events to the FDA as well as discuss them in their conferences on morbidity and mortality. Current stent technology is far from ideal, and it will be a long time before a stent is developed that is not associated with significant airway problems. Therefore, recognizing the potential complications prior to stent placement is the best way to avoid them. Airway stenting has become a common technique for treating central airway obstruction (CAO) caused by a variety of malignant and benign diseases. The original stents used by Duvall and Bauer,1Duvall AJ Bauer W An endoscopically introducible T-tube for tracheal stenosis.Laryngoscope. 1977; 87: 2031-2037Crossref PubMed Scopus (24) Google Scholar Cooper et al,2Cooper JD Pearson FG Patterson GA et al.Use of silicone stents in the management of airway problems.Ann Thorac Surg. 1989; 47: 371-378Abstract Full Text PDF PubMed Scopus (175) Google Scholar and Dumon3Dumon JF A dedicated tracheobronchial stent.Chest. 1990; 97: 328-332Abstract Full Text Full Text PDF PubMed Scopus (557) Google Scholar were silastic and required general anesthesia and rigid bronchoscopy for placement. The advent of the Wallstent (Boston Scientific Corporation; Natick, MA) introduced a new generation of stents that were metallic, self-expanding, and easily deployable, the so-called self-expanding metal stent (SEMS). However, the ease of deployment came with a cost. Over time, the metallic stents integrate into the airway, leading to complications such as stent fracture, erosion into adjacent structures, mucous retention, and granulation tissue formation. This is especially true in patients with benign airway disease, whose life expectancy is not inherently limited by their primary disease and in whom the stents can exist for years. This point was highlighted by Stephens and Wood,4Stephens KE Wood DE Bronchoscopic management of central airway obstruction.J Thorac Cardiovasc Surg. 2000; 119: 289-296Abstract Full Text Full Text PDF PubMed Scopus (124) Google Scholar who found that the vast majority of all early and late deaths following airway procedures for patients with benign and malignant CAO occurred in the malignant group. Over the past 5 years, there has been an increase in the number of adverse events reported after the deployment of SEMS for benign airway disease. This apparent increase in metallic airway stent failures led the Food and Drug Administration (FDA) to publish an advisory on the use of metallic stents in patients with benign airway disease in 2005 (Fig 1).5Food and Drug Administration. FDA public health notification: complications from metallic tracheal stents in patients with benign airway disorders, 2005. Available at: www.fda.gov/cdrh/safety/072905-tracheal.html. Accessed January 15, 2007Google Scholar Despite the publishing of this advisory, there still are no consensus recommendations for the use of SEMS in patients with benign CAO. Many physicians who regularly treat patients with CAO have seen and managed complications of metallic stents placed for nonmalignant disease. Despite this fact, several studies6Saad CP Murthy S Krizmanich G et al.Self-expandable metallic airway stents and flexible bronchoscopy: long-term outcome analysis.Chest. 2003; 124: 1993-1999Abstract Full Text Full Text PDF PubMed Scopus (253) Google Scholar7Madden BP Loke TK Sheth AC Do expandable metallic airway stents have a role in the management of patients with benign tracheobronchial disease?.Ann Thorac Surg. 2006; 82: 274-278Abstract Full Text Full Text PDF PubMed Scopus (127) Google Scholar8Thornton RH Gordon RL Kerlan RK et al.Outcomes of tracheobronchial stent placement for benign disease.Radiology. 2006; 240: 273-282Crossref PubMed Scopus (71) Google Scholar have shown that SEMS can be used successfully in patients with benign CAO but with complication rates that approach 45%. Disastrous complications include erosion of stents into adjacent structures.9Shiraishi T Shirakusa T Ninomiya H et al.Penetration to the aortic wall by a metal airway stent. A successfully treated case with left pneumonectomy and aortic repair.J Cardiovasc Surg. 2005; 46: 473-475PubMed Google Scholar More commonly, stents can become colonized with bacteria, leading to increased mucous production and formation of granulation tissue. Noppen and colleagues10Noppen M Pierard D Meysman M et al.Bacterial colonization of central airways after stenting.Am J Respir Crit Care Med. 1999; 160: 672-677Crossref PubMed Scopus (90) Google Scholar reported an 80% incidence of bacterial colonization after airway stent placement in patients without evidence of colonization prior to stenting. Pathogens included pseudomonas, Staphylococcus aureus, Streptococcus pneumonia, and klebsiella.10Noppen M Pierard D Meysman M et al.Bacterial colonization of central airways after stenting.Am J Respir Crit Care Med. 1999; 160: 672-677Crossref PubMed Scopus (90) Google Scholar This is compared to a study11Noppen M Perrard D Meysman M et al.Absence of bacterial colonization of the airways after therapeutic rigid bronchoscopy without stenting.Eur Respir J. 2000; 16: 1147-1151Crossref PubMed Scopus (8) Google Scholar that showed a 20% decrease in the incidence of bacterial airway colonization in patients with airway obstruction following therapeutic rigid bronchoscopy without subsequent stent placement. Although bacterial colonization can occur also with silastic stents, the ability to remove these stents makes this issue less critical. While removal of granulation tissue in a stent can be achieved relatively easily with Nd-YAG laser, cryotherapy, or argon beam coagulation, complete removal of an endothelialized or infected incorporated stent may be necessary. This procedure is difficult and can be extremely hazardous to the patient.12Murthy S Gildea TR Mehta AC Removal of self-expanding metallic stents: is it possible?.Semin Respir Crit Care Med. 2004; 25: 381-385Crossref PubMed Scopus (33) Google Scholar Lunn et al13Lunn W Feller-Kopman D Wahidi M et al.Endoscopic removal of metallic airway stents.Chest. 2005; 127: 2106-2112Abstract Full Text Full Text PDF PubMed Scopus (118) Google Scholar reported on stent extractions in 30 patients, 20 of whom had benign airway disease, and found that 97% of the complications associated with the stent extraction occurred in the benign CAO group and included mucosal tears, retained stent fragments, and airway obstruction. All of the difficulties encountered in patients with long-term airway SEMS highlight the point that SEMS should be avoided whenever possible in patients with benign CAO, with exceptions for patients with inoperable disease or significant comorbidities that render them inoperable. Even in these patients, other therapies such as airway debridement or dilatation and the placement of removable stents should be considered prior to the placement of a SEMS. Therapeutic strategies in these patients are best dealt with in a multidisciplinary setting, where pulmonologists and surgeons, knowledgeable in airway diseases, can decide on the best therapy for the patient. Postsurgical CAO involving anastomotic strictures following lung transplantation or tracheal resection is best dealt with at institutions that are used to dealing with these patients,14Mughal MM Gildea TR Murthy S et al.Short-term deployment of self-expanding metallic stents facilitates healing of bronchial dehiscence.Am J Respir Crit Care Med. 2005; 172: 768-771Crossref PubMed Scopus (113) Google Scholar who may require frequent bronchoscopies, stent changes, or other surgical procedures to treat the involved airway. The FDA advisory highlighted an ongoing concern held by many pulmonologists and surgeons: stents are being employed in patients with benign airway obstruction without consideration for other therapeutic modalities and without consideration of the possible long-term complications inherent with the use of SEMS. The members of the American College of Chest Physicians (ACCP) Interventional and Chest Diagnostics Network Steering Committee fully support the FDA warning. Although there are no universally agreed-on guidelines defining proficiency for stent placement, all physicians who utilize endotracheal/bronchial therapies should be familiar with the ACCP and the American Thoracic Society/European Respiratory Society guidelines regarding recommended provider training requirements, clinical experience, and competency.15Ernst A Silvestri GA Johnstone D Interventional pulmonary procedures: guidelines from the American College of Chest Physicians.Chest. 2003; 123: 1693-1717Abstract Full Text Full Text PDF PubMed Scopus (522) Google Scholar16Bolliger CT Mathur PN Beamis JF et al.ERS/ATS statement on interventional pulmonology: European Respiratory Society/American Thoracic Society.Eur Respir J. 2002; 19: 356-373Crossref PubMed Scopus (481) Google Scholar Furthermore, all physicians who perform airway stenting should report all adverse device events to the FDA as well as discuss them in their conferences on morbidity and mortality. Current stent technology is far from ideal, and it will be a long time before a stent is developed that is not associated with significant airway problems. Therefore, recognizing the potential complications prior to stent placement is the best way to avoid them.