New Hope For Treatment Of Severe Emphysema: Minimally Invasive Metal Implant Makes Its First Appearance At Berlin Congress

Main Category: Respiratory / Asthma
Also Included In: Medical Devices / Diagnostics
Article Date: 06 Oct 2008 - 1:00 PDT

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A new type of implant for the treatment of severe emphysema, which can be placed using a simple, non-invasive procedure, has made its first appearance at the Annual Congress of the European Respiratory Society (ERS) in Berlin, to considerable acclaim.

This device - though, to date, tested on only a handful of patients - could provide a viable alternative to the invasive treatments currently used, including lung volume reduction surgery and lung transplants. The new, revolutionary approach was presented to the Congress in three scientific communications that provided an assessment of the new device's feasibility and effectiveness.

Nobody at the Congress could fail to be aware that, in Europe alone, over 13.5 million people have chronic obstructive pulmonary disease (COPD). This is an umbrella term, covering both chronic bronchitis and emphysema, conditions which lead to increasingly disabling breathlessness over time and kill 145,000 Europeans each year. COPD's impact on health costs is close to 700 million euros annually.

One of the underlying pathologies, emphysema, is an irreversible condition caused by a loss of elasticity in the lungs following destruction of the walls of the alveoli, small cavities responsible for gas exchange. When these walls are damaged, air becomes blocked in the lung, which begins to swell, making breathing increasingly difficult.

Over time, the patient becomes more and more short of breath and immunity is compromised, so that the condition becomes increasingly life-threatening.

While there are a number of drugs and other treatments that can alleviate symptoms in milder forms of the disease, severe emphysema is a major challenge. When it reaches an advanced stage, the gold standard consists of surgically removing the diseased parts of the lung, which is extremely invasive and carries a high risk of mortality. Lung transplant is also an option, but remains rare because of a shortage of donors.

There have been several attempts in recent years to develop implants, but success has been limited, largely because the emphysematous lung is characterised by a number of collateral airways that bypass the implant.

No surgery needed

This is the context in which the new device, presented to the ERS Congress by American and German teams, makes its promising debut. The implant, designed to restore or improve the patient's normal breathing mechanism, is made of super-elastic nitinol (a metal alloy). It aims to compress the lung tissue, restore its elasticity and reduce the excessive swelling of the emphysema-affected lung.

Unlike the current invasive surgical procedures, placement of the implant is carried out using only a bronchoscope, a small, flexible tube inserted in the lungs through the mouth, without any need for surgery or incision.

The end goal is the same as with the standard surgical treatment - to reduce lung volume - but without the need to excise areas of the lung, and without the mortality and morbidity risks that surgery involves. Furthermore, its effectiveness should not be undermined by air bypassing the treated area.

Hopes confirmed

It seems that these hopes are being borne out, to judge by the spectacular results announced in Berlin by Felix Herth (Heidelberg University Thorax Clinic, Germany) and his American colleagues, following the first ever use of the new device in five patients with severe emphysema.

Before implantation, the researchers had carried out the standard tests for lung function, breathing capacity and quality of life. A single lung was treated, with the intention of treating the other three months later.

The first triumph, as Herth and his colleagues told the Congress, was that the procedure was found to be safe, and was well tolerated by the patients, aged 61 on average, who were able to go home after three days. The study kept the patients in hospital for 72 hours so that their health could be comprehensively monitored, "but in future patients will be able to go home the next morning", Herth explained.

There were few device related adverse events. Three of the five patients experienced shortness of breath or coughing that were possibly related to the device. "But all resolved spontaneously or with standard medical treatment", Herth added.

And the procedure proved highly effective, according to the figures announced in Berlin. Three-month follow-up showed, for all tests, an observed improvement in lung function, comfort and quality of life for the five patients.

For example, in some patients FEV1 (forced expiratory volume in one second) rose by 18% and patients on average were able to walk an additional 38 metres in the traditional six-minute walking test. Quality of life, measured using the St. George's Respiratory Questionnaire, was found to have improved significantly in four of the five patients.

Takes less than half an hour

The results presented to the Congress confirm those obtained from preliminary studies on human tissue and on animals, which had tested the feasibility and safety of the new technique.

One such study had placed lungs in a machine that replicated the functioning of the chest cavity. The lungs were then filled with air in order to measure their volume and air pressure before and after the implants were placed. In total, 213 implants were placed via bronchoscopy in 68 excised lungs. In the second stage, following optimisation of the method, ten more implants were placed in one set of dog lungs, one set of pig lungs, and two sets of emphysematous human lungs.

The volume was reduced from an average of 1.462 ml before the procedure to 996 ml afterwards, which is comparable to that achieved by lung volume reduction surgery.

Herth's pride at these initial results is evident. "And this technique has further advantages", he told the Congress. "On humans, the implant can be placed in less than half an hour, while on animals we were in fact able to do it in less than two minutes, within a centimetre of the target site."

The preliminary studies on pigs also showed, when the implants were removed two months later, that they had barely moved at all from the original position.

"This study is highly significant", the Congress was told by Armin Ernst of Beth Israel Deaconess Medical Center, Boston, who represented the American teams. "For the first time, a technology has been designed specifically to restore bronchiolar elasticity. In the future, this will help thousands of patients with emphysema."

On the basis of the results presented in Berlin, other centres throughout Europe will now be able to undertake similar studies.

European Respiratory Society

European Respiratory Society Annual Congress

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