New Study on Endobronchial Valves as Treatment for Emphysema
The results of a new study evaluating placement of valves inside the lung – called bronchoscopic lung volume reduction – was published in the December 10, 2015, issue of the New England Journal of Medicine.
Background: With bronchoscopic lung volume reduction, valves are placed into the breathing tubes to block the flow of air out of the specific area of the lung. This collapses part of the “bad” lung which is not functioning and allows the “good lung” to expand. This allows the diaphragm (the main breathing muscle) to work more effectively. Ideally, this will improve lung function and make it easier to breathe. A diagram of how bronchoscopy is done is shown on the left below; a view of one of the valves used in the study is shown on the right below.
Unfortunately, this procedure does not work for everyone who has emphysema. Researchers around the world are trying to find out the best candidates for this treatment. One reason that bronchoscopic lung volume reduction may not work is if someone has a hole or defect in the fissure that separates lobes in the lung. A brief anatomy lesson will help to explain this concern. There are 3 lobes or discrete parts in the right lung and 2 lobes or discrete parts in the left lung. In the figure below, fissures are shown by black curves.
In some individuals, small openings or pores allow air to flow across the fissure from one lobe to another. This flow is called collateral ventilation. However, this is not beneficial if the goal is to collapse a part of “bad” lung. The collateral ventilation allows air to bypass the lung blocked by the valves, just like a bypass road allows you to drive around or bypass a city.
Study: Klooster and colleagues at the University Medical Center in Groningen, Netherlands, were able to measure whether someone had collateral ventilation or not. In those who did not have collateral ventilation, 34 patients received endobronchial valves and 34 patients were the control group and treated with standard medical therapy.
Findings at 6 months: There were significant increases in breathing tests [by 140 ml in how much air can be exhaled in one second (FEV1) and by 347 ml in vital capacity (FVC)] and in the distance walked in 6 minutes (by 74 meters) in the valve group compared with the control group. There were 23 serious adverse events in the valve group and 5 in the control group. One person who received valves died. Some individuals required removal of the valves (15%) or replacement of the valves (12%).
My Comment: These findings make sense. If you are going to have valves placed inside of your breathing tubes to collapse areas damaged by emphysema, the treatment team should make sure that you do not have collateral ventilation. This should lead to better overall benefits of bronchoscopic lung volume reduction.
Although the authors had patients report on their quality of life, I am disappointed that the researchers did not have the participants rate their shortness of breath with a valid questionnaire. Those with emphysema are bothered most by their breathing difficulty, and being able to breathe easier is one of the key goals of treatment.
Like another study that I summarized in September 2015 under COPD News, there are risks with the procedure and you need to weigh possible benefits and possible risks. Certainly, you should discuss these with you doctor and the specialists who perform this procedure.