According to Canadian researchers, asthma patients' quality of life can be drastically improved by removing the muscle tissue (by heating it) in the hyperactive airways. This reduces the intensity of the problem.
The investigators announced this during CHEST 2006, the annual meeting of the American College of Chest Physicians.
The Asthma Intervention Research trial was conducted on 108 patients of an average age of 39.4 years who had poorly controlled moderate-to-severe asthma. Even the best drug therapy with corticosteroids and long-acting beta-agonists could not control their asthma.
FEV1 (forced expiration volume in 1 second) is a test generally used to measure lung function. The patients had FEV1 levels 60-80% of normal at the beginning of the study.
Dr. Michel Laviolette of Laval University in Sainte-Foy, Quebec, and his colleagues divided the patients at random into 2 groups, the control group and the group that would undergo bronchial thermoplasty. In this procedure, a catheter with a thermal energy tip reduces smooth muscle mass in all reachable airways. Nearly 45 activations were delivered in every session that lasted 30 minutes. Three such sessions of thermoplasty were performed. The patients were then assessed 3, 6 and 12 months after thermoplasty and the FEV1 was also measured each time.
"Patients also refrained from using long-acting beta-agonists for two weeks before each assessment to destabilize disease and capture true disease activity and get a better assessment of the efficacy of thermoplasty," Laviolette explained.
"There was a 50-percent reduction in exacerbation rates in the thermoplasty group compared with the controls, " Laviolette announced. "The need for asthma medication was also significantly reduced and quality of life scores were significantly higher in thermoplasty patients.
"There was a significant change in disease exacerbation in thermoplasty patients. There was no change or a worsening of exacerbations in controls," he said. "The change in quality of life was really clinically significant."
Thermoplasty has the side effect of deterioration of asthma condition within a day after the procedure. However, it subsides within a few weeks.
"There was almost no smooth muscle left after thermoplasty," Laviolette reported while showing tissue slides of airways before and after the thermoplasty.
He said, "Animal studies of thermoplasty show that the positive changes in airways have persist for at least three years so far."
"This is clearly one of the most original studies that I heard here," Dr. Peter R. Smith of Long Island College Hospital in Brooklyn, New York told Reuters Health. Smith participated in the discussion that followed Laviolette's presentation. "As a pulmonologist in a tertiary care hospital, I am still faced with no other options in asthmatics on maximal (drug) therapy."