Thomas Gildea, M.D., a pulmonary specialist at Cleveland Clinic talks about a new device that is helping patients with serious breathing disorders.
Interview conducted by Ivanhoe Broadcast News in July 2016.
Why don’t we start off with some background on these stents. Can you first tell us what airway stents are typically used for?
Dr. Gildea: Airway stents are typically an option of last resort with individuals who have got failure of their airways. It’s usually because of some sort of extrinsic process meaning a tumor or a mass or some sort of intrinsic problems say inflammation or destruction of airway structures. The stent is an option of last resort because the stents themselves have problems. As soon as you put a foreign body in to someone’s airway or any structure for that matter they can cause problems with infection or in generating granulation tissue or obstructive problems in and of themselves. Typically it’s not just one disease, it could be cancer, and it could be benign disease an inflammatory disease that leads to airway failure. A number of circumstances.
As for the stents that are currently on the market for airway, what are some of the issues that you’ve had with them?
Dr. Gildea: We have lots of different kinds of stents; we have silicone stents that are prone to migration and they’re also prone to generate granulation tissue or an obstruction. They’re also relatively thick walled and they are known to cause problems with trapping secretions. There are metal stents which are very, very easy to place, they have a very thin wall profile but they suffer from metal fatigue and fracture and they come with a very limited number of sizes and shapes for any individual patient.
When you’re talking about airways you can get some very small spaces right, so do they always fit just right?
Dr. Gildea: No unfortunately, most stents are made only for the central airways, usually the trachea and main stem bronchi and rarely do we get beyond the largest airways. After that there’s no good stent for very small airways. When it comes to central airways everybody’s airways are slightly different, they’re not exactly circular, most airways are actually arcade shaped so an arch with a flat back wall. They also have bends and turns and they’re not exactly straight as the stents are made to be.
Tell us about the stents that you’ve created and how that process has come about.
Dr. Gildea: We have a number of patients with very complex airways. Particularly in the case of this patient that we have most commonly is these airway patients with inflammation and problems. We have a very large number of patients with a disease called GPA or ganulomatosis with polyangiitis formerly known as Wagener’s disease. One of the main components of that disease is airway damage. These folk’s airway strictures can occur anywhere, large airways and small airways, and in the patients that we’ve seen recently once you start treating them it becomes a problem. We try to treat them systemically first with medicines to control their disease. When that fails sometimes we do dilations on the inside of the airways, maybe do steroid injections and procedures to try to stabilize it from inside. Only when that doesn’t work do we consider stinting. In cases where we have used stinting stents themselves don’t fit very well and they don’t last very long. For persons with benign diseases who are expected to live a long time, the stents themselves become problems, they start to cause granulation tissue, they get infected, they break and then they cause the problems associated with the airways not being fit very well. When we run in to these challenges we have gone through a number of steps to alter the way we use stents, try to pick the right stent for the job. We’ve also gone through the process of customizing stents. Take a silicone stent and sew it together in a certain format to fit but those continue to have limitation. With the use of CT scanners and 3-D printing technology I can design a stent specifically for the patient that I’m treating and adjust for all the problems with that airway relative to size and shape that are necessary for that particular patient. All stents are not made with all the sizes I need. Using that I can generate a three dimensional prescription for that patient and by using that three dimensional prescription we can print a stent just for that patient and then go ahead and implant it.
How does it work, I know there’s only been a couple of cases but how has it worked so far, what have you seen?
Dr. Gildea: So far the results are very promising for patients who are coming in very frequently, every few weeks to every few months to have their stents fixed, the first patient we’ve placed the stent in he’s been out four months now without any significant complications. The hope is to not necessarily cure their disease by any stretch of the imagination but to extend the time between needing stent changes and hopefully extend it such a long time that the patients live a much better quality of life. So far it’s still not approved for use we’re doing these with compassionate use from the FDA approval only and we’re working towards clinical trials to start soon.
Do the patients say they feel a difference right away?
Dr. Gildea: Almost instaneously. When you have a bad fitting stent and you clean out the problems associated with the stent and print a new stent that fits then patients immediately feel better with their breathing.
Can you talk a little bit about the different applications of these 3D printers? We’ve seen a bunch of different things come out of this, how does that make you feel that you are the forefront of that?
Dr. Gildea: It’s very exciting. Obviously this isn’t a new idea; people are using 3D printers to solve a lot of problems. I derive some of my inspiration from some folks here at the Cleveland Clinic that have done 3D printing devices for hips and orthopedic products. Learning to acquire and use the same technology to solve our own problems in our specialties has been a really exciting process. To offer new options for patients who don’t have any options currently is a great you know, opportunity to have it at a place like this.
When these 3D printers started coming out and you saw the application did it go off right away that this could be a logical use for them, my specialty?
Dr. Gildea: Absolutely. The challenge of course then is understanding what materials are available that are biocompatible that can be put in individuals and patients, what the regulatory environment is about achieving these sorts of things. It’s been a great learning experience to partner with industry and other researchers to be able to bring these things directly to patients.
Anything we missed, anything else you want to add?
Dr. Gildea: No. Airway stents are typically used in individuals with very complex diseases that cause airway obstruction, specifically symptomatic airflow obstruction where individuals may get pneumonia or have severe shortness of breath or end up on a ventilator because they can’t clear secretions or control their breathing very well. It can happen with benign diseases like inflammatory disease, it can also happen with malignant diseases like lung cancer and metastatic cancer to the chest. Again stinting is an option of last resort, we only use it when you really can’t achieve a result any other way or with radiation or surgeries, and you try to do those things first. When we commit to a stent and having a stent is a lifelong commitment, as long as the person is alive we have to manage these stents and maybe hopefully get stent free some day and we can repair their airways.
END OF INTERVIEW
This information is intended for additional research purposes only. It is not to be used as a prescription or advice from Ivanhoe Broadcast News, Inc. or any medical professional interviewed. Ivanhoe Broadcast News, Inc. assumes no responsibility for the depth or accuracy of physician statements. Procedures or medicines apply to different people and medical factors; always consult your physician on medical matters.
If you would like more information, please contact:
Andrea Pacetti
Cleveland Clinic
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