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Melanie Cole (Host): Welcome to UAB Med Cast. I'm Melanie Cole, and I invite you to listen as we explore endobronchial valves for severe emphysema. Joining me is Dr. Surya Bhatt. He's an Associate Professor of Medicine in the Division of Pulmonary, Allergy and Critical Care at UAB Medicine. Dr. Bhatt, it's a pleasure to have you join us today. As we get started, can you tell us the idea behind lung volume reduction procedures? What is bronchoscopic lung volume reduction?

Surya Bhatt, MD (Guest): Sure. Lung volume reduction is a procedure that's intended for alleviating respiratory burden mainly in the form of symptoms of shortness of breath. Many patients with COPD, especially those with severe emphysema, develop significant air trapping. And this causes a reduction in their inspiratory capacity, meaning the ability to take a bigger breath and thus causing shortness of breath.

Lung volume reduction is a procedure in which we can deflate more effected lobes compared to non-affected lobes and hence reduce air trapping and hence significantly increase the inspiratory capacity. And this also leads to an improvement in lung function and an improvement in symptoms. Bronchoscopic lung volume reduction is a relatively new procedure. It's been around for about 13 to 14 years, but it's an advance over the previously mainstream lung volume process of performing it surgically. So, now we can perform this bronchoscopically by placing one way valves and effecting lobar deflation.

Host: And it leads to substantial improvements in lung function, symptoms, and certainly quality of life. Yes. But one of the most important things, discussing a bit is patient selection and how that has changed over the years. Can you speak about who's eligible and really who this procedure is indicated for?

Dr. Bhatt: Yes. This is it's very important to select the right patient for this procedure. When surgical procedures were introduced, it was predominantly targeting upper lobe emphysema, and it did not matter if there were intact fissures between the lobes or not. Whereas with bronchoscopic lung volume procedures, we have gradually seen an evolution of the inclusion criteria so much so that we can now actually target any of the lobes in the lung, either the upper or the lower, but the biggest criteria is that the fissure or the partition between the lobes has to be intact. If there is any breakage in the fissures or collateral ventilation, then this procedure is not going to be successful. Using the left upper lobe as an example, if the left upper lobe is targeted for deflation, but the oblique fissure on the left side has collaterals then air can leak from the lower lobe into the upper lobe and the procedure will not succeed. So, it is very important to identify patients with a significant amount of destruction in the target lobe. And also make sure that the fissures are intact. Also the patients who get more benefit are those who have what is called heterogeneous emphysema. Meaning emphysema is more in the target lobe, but there is a relatively healthy lobe on the same side, which can then expand and take over the role of the deflated lobe.

Host: So then what studies are needed to assess for candidacy and tell us a little bit about the tests required to select patients.

Dr. Bhatt: The most important is spirometry or lung function testing. So, patients should have severe enough lung disease. So that FEV1 should be between 15 to 45% predicted. And then it is important to confirm air trapping and hyperinflation. So, this is preferably done using a body plethysmograph and the total lung capacity should be at least 100% predicted or more.

And air trapping as defined by residual volume should be greater than at least 175% predicted. And then the oxygen transfer, which is determined by the diffusing capacity of carbon monoxide should be at least 20% predicted. And we also want to select patients who are not so good that they don't really benefit from this procedure, but are also not so sick that they may have more complications.

So we want to identify patients who have a six minute walk distance between 100 and 450 meters. And we also want to make sure that they do not have chronic respiratory failure. For example, they should not have a carbon dioxide on their blood gas of greater than 15 millimeter mercury.

Host: Well, then tell us a little bit about what the procedure involves Dr. Bhatt, and what are the potential downsides? Are there any complications you'd like to share?

Dr. Bhatt: Sure. The procedure itself is relatively simple. It can be done under conscious sedation or under general anesthesia. At our sidte, we prefer to do it under general anesthesia. It's a bronchoscopic procedure, meaning the patient is first made sleepy either with conscious sedation or general anesthesia, and then the bronchoscope is introduced into the lungs.

And the first step is to confirm that there are no collaterals. So we use something called a Chartis system where we inflate a balloon to deflate the target lobe temporarily. And the balloon has a central conduit in which there is a one-way sensing mechanism to see if air continues to come out of the target lobe. After awhile, if it stops coming out, that is confirmation that there are no collaterals, at which point we can proceed with the more permanent valves. So, we take out the temporary balloon and then we introduce valves into segments of the lobe. Usually depending on the size of the lobe, we may need anywhere between three to five valves. And these do not require any stitches. They are held by the tensile expansile force of the valves and they stay in place once they're inserted without any stitches.

Host: So do they ever need to be adjusted?

Dr. Bhatt: Sometimes they may need to be. And also there are some potential complications that we may encounter. Some are expected. Some may not be expected. The expected complications are one in four people get a pneumothorax or collapse of the entire lung, which can be treated with a chest tube. Some people get hemoptysis. That is seen in about 5% of patients. In about five to 10% of patients, there may be movement of the valve either by coughing or over time, it can migrate requiring repositioning of the valve in about five to 10% of the patients.

Host: What's been the experience Dr. Bhatt of patients to date with this treatment?

Dr. Bhatt: It depends on selection of the patients. So if we, in patients who have heterogeneous emphysema, meaning at least a 15% difference in the emphysema scores between the target and the non-target lobe, most patients can expect to achieve a 15 to 20% improvement in their lung function, or at least a 350 to 500 mil decrease in their residual volume, which is directly correlated with how they feel.

So in about half to two thirds of patients, I think feel considerably better. We also perform this procedure in people with what is called homogenous emphysema, meaning the amount of emphysema difference between the target and the non target lobe may not be 15%. It could be less than that. Those patients usually benefit, but they do not benefit to the same extent. They may get a 10 to 12% improvement in their FEV1.

Host: Where do you see this going now Dr. Bhatt? Because it's such an interesting procedure. You describe it so well, what do you see happening in the next 10 years in this, in this area?

Dr. Bhatt: I think this is a really exciting technology and very beneficial for patients with less morbidity compared to surgery. I think it is our role to identify the right people for this procedure, because we want to make sure that patients get the maximum benefit, given that there are some side effects and complications related to the procedure.

So we want to maximize the benefit, but reduce the risk. And also there are steps to try and identify patients better. We do need CT scans to identify if the fissure's are in intact. We do have the balloon procedure to confirm that the fissure's in intact, but in those in whom the fissures are not intact, we do need alternative procedures because valves will not work in them the way they are designed now.

There are attempts to try and seal the fissures either surgically or otherwise. There are also previous trials, which were not successful, but are being modified wherein, scarring agents were used so that you can actually achieve lung deflation bronchoscopically in other ways. And not just by placing one way valves.

Host: Wow. It's such an exciting time, really in your field. In summary, Doctor, let other physicians know what you'd like them to know about endobronchial valves for severe emphysema. And when you feel it's important that they refer their patients, so they know their patients are getting the best care at UAB Medicine.

Dr. Bhatt: I think any patient with significant symptom burden who are not responding to usual therapy in the form of bronchodilators and pulmonary rehabilitation and if they have stage three or stage four COPD by gold criteria, I think that's the time to think about whether they may be candidates for this procedure.

And we would suggest referring those kinds of patients to us for evaluation.

Host: Thank you so much, Dr. Bhatt for joining us. A physician can refer a patient to UAB Medicine by calling the mist line at 1-800-UAB-MIST, or you can always visit our website at UABmedicine.org/physician. That concludes this episode of UAB Med Cast. I'm Melanie Cole.