Details

Autor(en) / Beteiligte

• Danek, Christopher J
• Lombard, Charles M
• Dungworth, Donald L
• Cox, P. Gerard
• Miller, John D
• Biggs, Michael J
• Keast, Thomas M
• Loomas, Bryan E
• Wizeman, William J
• Hogg, James C
• Leff, Alan R

Titel

Reduction in airway hyperresponsiveness to methacholine by the application of RF energy in dogs

Ist Teil von

• Journal of applied physiology (1985), 2004-11, Vol.97 (5), p.1946-1953

Ort / Verlag

Bethesda, MD: Am Physiological Soc

Erscheinungsjahr

2004

Quelle

MEDLINE

Beschreibungen/Notizen

• 1 Asthmatx, 5 Broncus Technologies, Mountain View 94043; 2 Department of Pathology, Stanford University-El Camino Hospital, Mountain View 94040; 3 Department of Pathology, Microbiology, and Immunology, University of California at Davis, Davis, California 95616; 4 St. Joseph's Healthcare and Department of Medicine, McMaster University, Hamilton L8N 4A6; 6 St. Paul's Hospital, University of British Columbia, Vancouver, Canada V6Z 1Y6; and 7 Departments of Medicine and Neurobiology, Pharmacology, and Physiology, University of Chicago, Chicago, Illinois 60637 Submitted 1 December 2003 ; accepted in final form 6 July 2004 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. asthma; bronchoscopic procedures; airway smooth muscle; bronchial hyperreactivity; bronchial thermoplasty; radio frequency Address for reprint requests and other correspondence: C. J. Danek, Asthmatx, 1340 Space Pkwy., Mountain View, CA 94043 (E-mail: cdanek{at}asthmatx.com ).