Benign Airway Disorders Research Articles

Benign Tracheal Stenosis Should Never be Stented With Metallic Devices

In this issue of Archivos de Bronconeumologia Serrano et al.1 report the results of an elegant experimental study on the rabbit trachea. The authors hypothesise that drug-eluting stents attenuate granuloma formation leading to inflammatory stenosis, which is a well-known adverse effect of metallic stents on the tracheal epithelium. As commented by the authors in the text, in 2005 the US Food and Drug Administration alerted healthcare professionals “to serious complications associated with the use of metallic tracheal stents in patients with benign airway disorders. . .including all covered and uncovered metallic tracheal stents”.2 In that safety alert for medical products, potential complications were described as “obstructive granulation tissue, stenosis at the ends of the stent, migration of the stent, mucous plugging, infection, and stent fracture”. Moreover, the notification alerted against the use of metallic stents as a bridge for definitive therapies due to the risks associated with removal. FDA recommendations are supported by the authors’ data. In their series, 40% of the cases (14 out of 30 animals) died as a result of the procedure. In the metallic stent series, mortality due to tracheal obstruction occurred in 80% of cases (8/10 rabbits). Therefore, we totally agree with the authors’ main conclusion: steel stents should never be indicated for the treatment of inflammatory tracheal stenosis. The second conclusion of the investigation (nitinol tracheal stents are the least reactive) is arguable, and should be reported in a different manner, since in the authors’ series, 20% of the nitinol stent-treated cases (2 out of 10) died due to airway obstruction. This would be a non-acceptable rate of adverse events in clinical series. Thus, it should be clearly stated that nitinol stents used inside a healthy trachea, in the authors’ experimental setting, were associated with mortality in 20% of cases. The use of drug-eluting stents in the airways has been rarely reported. Chao et al.3 implanted biodegradable cis-platinum

Outcomes, Health-Care Resources Use, and Costs of Endoscopic Removal of Metallic Airway Stents

The use of self-expandable metallic airway stents (SEMAS) for airway compromise may be associated with significant complications requiring their removal/replacement. The aim of this study is to describe the complications, health-care resources use (HRU), and costs associated with endoscopic removal of SEMAS. A retrospective analysis of patients who underwent endoscopic removal of SEMAS during a 10-year period (January 2000-August 2009) was performed. HRU was analyzed in terms of the number of endoscopic procedures, hospital and ICU stay, need for mechanical ventilation and airway restenting, and estimation of respective hospital costs. Fifty-five SEMAS were removed from 46 patients with a mean age of 58.6 +/- 15.8 years. Eighty percent of the stents were placed for benign airway disorders with an average stent in situ duration of 292 days. The median number of removal and total procedures during each encounter was one and two, respectively. Patients required hospitalization and ICU admission in 78% and 39% of the encounters with a median length of stay of 3.5 and 0 days, respectively. The estimated median total cost per encounter to remove the stents was $10,700, ranging from $3,700 to $69,800. The measured outcomes were statistically significantly better when in situ stent duration was <or= 30 days (P < .05). Endoscopic removal of SEMAS is feasible; however, it is associated with significant complications, HRU, and costs. The use of SEMAS should be restricted to a well-selected patient population and should be planned by a team experienced with this type of therapeutic strategy.

Endoscopic Therapies and Stents for Benign Airway Disorders: Where Are We, and Where Are We Heading?

Benign strictures of the airway can be complex and challenging to manage. Although resection has the best long-term results, this is not always feasible, and there will be groups of patients who require additional therapy for failure after open operations or who are not surgical candidates and require endoluminal management. A number of stents are available; however, not all perform well for the longer duration that will be required for patients with benign compared with malignant strictures. For this reason, stenting should be considered a temporary solution or a last resort for patients with benign airway strictures. Combinational modalities hold promise; for example, radial laser incisions with dilatation and mitomycin C for tracheal stenosis. Many techniques, however, have been associated with failure, particularly for long strictures. Spray cryotherapy is a new technique that may have advantages over other treatments by modulating the healing response and resulting in improved healing and less refibrosis. A number of current and new therapies are reviewed in this article.

Are metallic stents really safe? A long-term analysis in lung transplant recipients

Airway complications affect 20% of all lung transplant recipients. Self-expandable metallic stents (SEMS) are one treatment option but their use in benign airway disorders is controversial. We studies the long-term safety of SEMS in lung transplant recipients. Between January 1998 and February 2008, all lung transplant recipients with SEMS were analysed retrospectively at a single centre. Complications were recorded until September 2008. In 65 (9.2%) out of 706 recipients, 111 (91% noncovered) bronchial SEMS were implanted a median (range) 133 (55-903) days after lung transplantation; follow-up was 777 (7-3.655) days. Clinical improvement was noted in 80% of recipients. The forced expiratory volume in 1 s increased by (mean+/-SD) 21+/-33%. Most frequent early complications were migration (3%) and mucus plugging (11%). No procedure-related deaths were noted. Re-stenosis occurred in 34 (52%) out of 65 recipients 85 (7-629) days after insertion. In multivariate analysis, stent insertion before post-operative day 90 was independently associated with an increased risk of re-stenosis (HR 3.29, 95% CI 1.50-7.18; p = 0.003). In 40% of recipients, new bacterial airway colonisation occurred after SEMS insertion. In SEMS patients, 5-yr survival was significantly lower than in the total cohort (60% versus 76%; p = 0.02). Late complications in lung transplant recipients treated with SEMS are frequent. The major problems are re-stenosis and airway colonisation.

Removal of Covered Self-Expandable Metallic Airway Stents in Benign Disorders: Indications, Technique, and Outcomes

To describe the technique and outcome of removal of self-expandable metallic airway stents (SEMAS) in a series of patients who underwent stenting for benign airway stenoses.A retrospective cohort analysis of patients with benign airway disorders treated with SEMAS between 1997 and 2003, who presented with an indication for stent removal in a tertiary-care hospital, and referral interventional pulmonology clinic.During the study period, 49 SEMAS were inserted in 39 patients for treatment of benign airway disorders. Ten of these 39 patients (25.6%), bearing 12 covered stents, presented with an indication for stent removal. Data of these cases were extracted from electronic files kept in our institution archive.Indications for stent removal included excessive or recurrent granuloma formation (five cases), recurrence of stenosis after stent failure (one case), stent fracture (two cases), and accomplishment of treatment (two cases). In all of these cases, covered versions of SEMAS had been placed either in the trachea or in a main bronchus. In contrast to many previous reports, these stents proved to be absolutely retrievable even if some difficulties were encountered. In all cases, however, removal was successful without major complications. All patients resumed normal spontaneous ventilation postoperatively, and follow-up was uneventful. Average duration of stenting before removal was 16.2 +/- 17.5 months (+/- SD) [range, 1 to 60 months].We conclude that although placement of SEMAS is assumed to be permanent in patients with benign airway disorders, an indication for stent removal is often observed (25.6% in our series). The covered SEMAS can be effectively and safely removed if needed without major sequelae. Nevertheless, new technical improvements in metallic stent design and materials may help reinforce the concept of a retrievable metallic airway stent, which may offer significant clinical advantages.