 |
 |
 |
Our commitment to
excellence.
By radically changing the standard of care, Asthmatx will become the leading provider of therapeutic medical devices for patients who suffer from asthma.
FAQ
What is the AIR2 Trial?
The AIR2 Trial: The objective of this randomized, double blind, sham-controlled study is to evaluate the safety and efficacy of Bronchial Thermoplasty with the Alair® System in a population of subjects with severe asthma who are still symptomatic despite being managed on conventional therapy.
Danek C, Lombard C, Dungworth D, et al, Reduction in Hyperresponsiveness to Methacholine by the Application of RF Energy in Dogs, J Appl Physiol 2004;97:1946-1953
Reduction in Airway Hyperresponsiveness to Methacholine by the Application of RF Energy in Dogs
Christopher J. Danek,1 Charles M. Lombard,2 Donald L. Dungworth,3 P. Gerard Cox,4 John D. Miller,4 Michael J. Biggs,5 Thomas M. Keast,5 Bryan E. Loomas,5 William J. Wizeman,1 James C. Hogg,6 and Alan R. Leff7
1Asthmatx, 5Broncus Technologies, Mountain View 94043; 2Department of Pathology, Stanford University-El Camino Hospital, Mountain View 94040; 3Department of Pathology, Microbiology, and Immunology, University of California at Davis, Davis, California 95616; 4St. Joseph's Healthcare and Department of Medicine, McMaster University, Hamilton L8N 4A6; 6St. Paul's Hospital, University of British Columbia, Vancouver, Canada V6Z 1Y6; and 7Departments of Medicine and Neurobiology, Pharmacology, and Physiology, University of Chicago, Chicago, Illinois 60637
Abstract
We delivered controlled radio frequency energy to the airways of anesthetized, ventilated dogs to examine the effect of this treatment on reducing airway narrowing caused by a known airway constrictor. The airways of 11 dogs were treated with a specially designed bronchial catheter in three of four lung regions. Treatments in each of the three treated lung regions were controlled to a different temperature (55, 65, and 75°C); the untreated lung region served as a control. We measured airway responsiveness to local methacholine chloride (MCh) challenge before and after treatment and examined posttreatment histology to 3 yr. Treatments controlled to 65°C as well as 75°C persistently and significantly reduced airway responsiveness to local MCh challenge (P ≤ 0.022). Airway responsiveness (mean percent decrease in airway diameter after MCh challenge) averaged from 6 mo to 3 yr posttreatment was 79 ± 2.2% in control airways vs. 39 ± 2.6% (P ≤ 0.001) for airways treated at 65°C, and 26 ± 2.7% (P ≤ 0.001) for airways treated at 75°C. Treatment effects were confined to the airway wall and the immediate peribronchial region on histological examination. Airway responsiveness to local MCh challenge was inversely correlated to the extent of altered airway smooth muscle observed in histology (r = –0.54, P < 0.001). We conclude that the temperature-controlled application of radio frequency energy to the airways can reduce airway responsiveness to MCh for at least 3 yr in dogs by reducing airway smooth muscle contractility.
Key Words
asthma • bronchoscopic procedures • airway smooth muscle • bronchial hyperreactivity • bronchial thermoplasty • radio frequency
CAUTION: The Alair® System is an Investigational device.
It is limited by United States law to investigational use. To be used by Qualified Investigators only.
Alair, Asthmatx, and It's about breathing are trademarks or registered trademarks of Asthmatx, Inc.
Copyright © 2006, Asthmatx Inc. All Rights Reserved.
Last Updated: August 22, 2007
