1Director of Pulmonary Special Procedures and the Lung Cancer Center, Virginia Hospital Center, 2Chief, Division of Pulmonary Critical Care and Sleep Medicine, Virginia Hospital Center
Duhamel, D. R., Hales, J. B. Bronchial Thermoplasty: A Novel Therapeutic Approach to Severe Asthma. J. Vis. Exp. (45), e2428, doi:10.3791/2428 (2010).
Bronchial thermoplasty is a non-drug procedure for severe persistent asthma that delivers thermal energy to the airway wall in a precisely controlled manner to reduce excessive airway smooth muscle. Reducing airway smooth muscle decreases the ability of the airways to constrict, thereby reducing the frequency of asthma attacks. Bronchial thermoplasty is delivered by the Alair System and is performed in three outpatient procedure visits, each scheduled approximately three weeks apart. The first procedure treats the airways of the right lower lobe, the second treats the airways of the left lower lobe and the third and final procedure treats the airways in both upper lobes. After all three procedures are performed the bronchial thermoplasty treatment is complete.
Bronchial thermoplasty is performed during bronchoscopy with the patient under moderate sedation. All accessible airways distal to the mainstem bronchi between 3 and 10 mm in diameter, with the exception of the right middle lobe, are treated under bronchoscopic visualization. Contiguous and non-overlapping activations of the device are used, moving from distal to proximal along the length of the airway, and systematically from airway to airway as described previously. Although conceptually straightforward, the actual execution of bronchial thermoplasty is quite intricate and procedural duration for the treatment of a single lobe is often substantially longer than encountered during routine bronchoscopy. As such, bronchial thermoplasty should be considered a complex interventional bronchoscopy and is intended for the experienced bronchoscopist. Optimal patient management is critical in any such complex and longer duration bronchoscopic procedure. This article discusses the importance of careful patient selection, patient preparation, patient management, procedure duration, postoperative care and follow-up to ensure that bronchial thermoplasty is performed safely.
Bronchial thermoplasty is expected to complement asthma maintenance medications by providing long-lasting asthma control and improving asthma-related quality of life of patients with severe asthma. In addition, bronchial thermoplasty has been demonstrated to reduce severe exacerbations (asthma attacks) emergency rooms visits for respiratory symptoms, and time lost from work, school and other daily activities due to asthma.
Asthma is a serious public health problem. The current estimate is that 20 million people in the United States suffer from asthma. Each year in the United States alone, there are approximately 13.6 million unscheduled physician office visits, 1.8 million emergency room visits, 0.5 million hospitalizations, and 4,000 deaths (NCHS 2005) due to asthma. The estimated annual cost of asthma in the United States is approximately $19.7 billion. This total includes $5 billion in indirect costs, due to more than 14.5 million lost work days, and $14.7 billion in direct costs, such as asthma medications, unscheduled physician office visits, emergency room visits and hospitalizations (American Lung Association 2007).
Ten percent of the more than 20 million Americans with asthma are diagnosed as having severe asthma. This group of severe asthmatics, however, is responsible for a disproportionate share of the morbidity associated with the disease. Thus, this 10% of patients with the most severe asthma are responsible for the majority of asthma-related healthcare burden, represented by the costs of hospitalizations, ER visits, physician office visits, and use of medications (Cisternas et al, 2003)
Despite regular treatment with high doses of available asthma medications, patients with severe asthma experience frequent and serious symptoms including exacerbations that may be life-threatening and require urgent resuscitative measures including intubation and mechanical ventilation, until the airway obstruction can be relieved. Exacerbations requiring medical intervention result in significant healthcare costs and affect the quality of life for the patient and family. This increased burden of severe asthma reflects the inability of the existing treatment options to adequately control asthma in patients with severe disease.
2. Case Presentation:
The typical patient is about 40 years old, has a history of poorly controlled severe asthma, and despite taking Advair, Symbicort or other equivalent combinations of ICS + LABA twice a day, still experiences difficulty in daily activities due to asthma symptoms.
Bronchial thermoplasty is typically administered in a hospital outpatient bronchoscopy or endoscopy suite or operating room. The patient should be stable to undergo bronchoscopy and the bronchoscopist needs to ensure that the patient remains a good candidate for bronchial thermoplasty by following the patient selection criteria outlined below. In some cases, the procedure may be safely performed on an in-patient basis where the patient can be monitored for a longer period of time before discharge. Patients who are described in the Precautions section 3.4 below might be such candidates.
3. Patient Selection:
4. Bronchial Thermoplasty Procedure:
5. Post Procedure Follow Up:
The Asthma Intervention Research 2 (AIR2) Trial evaluated the safety and effectiveness of the Alair Bronchial Thermoplasty System. The data from that study was submitted to the FDA and was the basis for the agency's approval of a novel device for the treatment of asthma. The AIR2 data was also published in the January 15, 2010 issue of the American Journal of Respiratory and Critical Care Medicine (AJRCCM). The trial demonstrated that treatment with the Alair System resulted in improved asthma quality of life, as well the following clinically significant benefits over sham during long-term follow-up:
Bronchial thermoplasty delivered by the Alair System provides a novel, procedure-based treatment for severe asthma that is refractory to conventional therapy. Pulmonologists, allergists, asthma experts, and respiratory therapists should become familiar with the use of bronchial thermoplasty and appropriate selection and management of patients for this procedure. Randomized, controlled clinical trials to date with bronchial thermoplasty have demonstrated significant improvement in outcomes that are important to our patients: quality of life, asthma symptoms, severe exacerbations requiring corticosteroids, days lost from work/school/other daily activities due to asthma, and healthcare utilization. Unlike the currently used drug therapies which require daily use to manage symptoms, bronchial thermoplasty provides benefits and improvements in overall asthma control that are long lasting.
The authors were clinical investigators in the AIR2 Trial, the pivotal clinical study supporting the FDA approval of the Alair Bronchial Thermoplasty System.
Supported by Asthmatx, Inc.
Alair and Asthmatx are registered trademarks of Asthmatx, Inc.
Advair is a registered trademark of GlaxoSmithKline, Inc.
Symbicort is a registered trademark of AstraZeneca, Inc.
|Standard diagnostic High Frequency Fiberoptic Bronchoscope||minimum 2.0 mm working channel|
|Alair Radio Frequency Controller|
|Alair Bronchial Thermoplasty Catheter|
|Gel Type Patient Return Electrode|
|Continuous vital signs monitoring||heart rate, blood pressure, temperature, respiratory rate, pulse oximetry|
|Local Anesthetic: Lidocaine 1-2% (jelly and solution)|
|Sedatives: Midazolam and Fentanyl|
|Antiemetics: ondanestron or like|
|Anticholinergic drying agent: Atropine or Glycopyrrolate|
|Prednisone||3 days before, day of and day after procedure|
|Peripheral IV line|
|Supplemental oxygen||less than 40% via oral or nasal cannula|
|Pulmonary Function Testing with Body Plethysmography|
|Lung Map or procedure form for planning and recording of treatment|