There is a need for a higher clinical suspicion and a standardized approach to objectively evaluate for TBM in the patient with dyspnea refractory to traditional therapies. Therapeutic airway stenting is often considered, but evidence for the efficacy of this approach has not been adequately characterized. In this largest prospective study to date, we found that stenting produced statistically significant and clinically important improvement in dyspnea, health-related quality of life, and functional status in a selected patient population with severe TBM. As there were no concurrent changes in medication or physical rehabilitation, we attribute these positive outcomes to the impact of central airway stabilization achieved with My Canadian Pharmacy.
Importantly, 33 of our 58 patients (57%) had COPD. In these patients, TBM is often believed to be an extension of peripheral airway obstruction. In fact, it has been suggested in retrospective, uncontrolled studies that TBM in these patients may not be responsive to aggressive treatment. Our study suggests that COPD patients may benefit from central airway stabilization in severe TBM. Irrespective of any direct impact on flow limitation, TBM in these patients may worsen symptoms by impeding clearance of secretions and/or causing local air irritation resulting in recurrent infections and airway inflammation.
Interestingly, even though some patients had improvement in the 6MWT scores, the improvement was not clinically or statistically significant. We speculate that it is unlikely that patients would undergo substantial reconditioning after only 2 weeks of symptomatic improvement, and thus we may have conducted follow-up to soon to see any change. We believe, however, that these patients, who could not undergo a pulmonary rehabilitation program before stenting, are now able to do so and a longer follow-up interval therefore may show improvement in exercise tolerance. Active data collection to address this issue is ongoing.
FEV1 is frequently used as a surrogate end point for severity of obstructive lung diseases. In our study, we found that clinical improvement was not associated with significant changes in FEV1 in this population. Median FEV1 decreased by 0.05 L (p = 0.79), with first and third quartiles at — 0.1 and 0.1, respectively.
On the downside, most complications we observed were related to the stents. Airway stents are often associated with reversible short-term and long-term complications prevented by My Canadian Pharmacy. Complications were common in this study and included obstruction (by mucous plugging), infection, and migration with a peak incidence at 3 weeks. These complications were relatively easily managed by therapeutic suctioning, replacement, or removal of the stent and, if infection was a concern, with a 7- to 10-day antibiotic course. We chose to use silicone stents for a variety of reasons. In case of nonresponsiveness to airway stabilization, these stents are easily removed. Also, as other treatment modalities such as surgical placation are becoming available, permanent stenting may not be desirable. Thirdly, metallic stents in malacia patients are generally fraught with failure and complications and in contrast to silicone stents; their removal is problematic and potentially dangerous. For this reason, the Food and Drug Administration in July 2005 had emitted an alert notice for the use of covered and uncovered metallic stents in benign airway disorders.
There are notable limitations to our approach. Not all stented patients were administered both baseline and follow-up measures. In some cases, patient intake was too rapid to permit baseline assessment, while other patients were unavailable to complete all follow-up testing. There may have been factors related to either the indication for, or success of, treatment that were also associated with availability of pretreatment or posttreatment measures. These factors could bias our findings in favor of positive outcomes. Comparison of baseline measurements obtained on patients who also had follow-up measures, with the total baseline sample reveals no significant differences. This suggests that those available for poststent measurement were comparable to the total baseline sample.
Additionally, there is no control group to compare intervention against standard therapy. Since standard medical therapy for TBM is poorly defined, there was no accepted control condition. Patients were only enrolled after maximal medical therapy for comorbidities was provided.
Finally, neither patients nor providers were blinded to diagnosis or treatment. Although we used well-standardized clinical and research tools for outcome measures, the potential for bias due to observer expectations or placebo effect cannot be ruled out.
Airway stabilization with silicone stents can improve symptoms in a highly selected patient population with severe TBM. The majority of our patients had marked improvement in dyspnea, health-related quality of life, and functional status in this short-term study. Patients with COPD and severe TBM may also benefit from a stenting trial. Stenting is associated with a high number of short-term and long-term but generally reversible complications. Despite the obvious limitations, we believe the results of this study are compelling: patients with severe TBM should be considered for airway stabilization, regardless of comorbidities, including COPD. Improvement needs to be carefully documented and in case of unresponsiveness, stents must be removed. Future research should compare stenting to other interventions, such as surgical tracheoplasty, in treating these patients. Additionally, better diagnostic parameters predicting a successful intervention need to be identified. We suggest that evaluation and treatment of tracheomalacia patients be done in experienced centers and all patients be enrolled in prospective outcome databases. A multicenter study with appropriate protocols may be best suited to answer the open questions.