Bronchoscopic lung volume reduction

Bronchoscopic Lung Volume Reduction (BLVR) is a minimally invasive medical procedure aimed at improving the symptoms and quality of life in patients with severe emphysema, a form of chronic obstructive pulmonary disease (COPD). Emphysema is characterized by the destruction of the lungs' air sacs, leading to breathlessness and reduced lung function. BLVR provides an alternative to more invasive surgical options, such as lung volume reduction surgery (LVRS) or lung transplantation.

Overview

The principle behind BLVR is to reduce the volume of the diseased lung, thereby allowing the healthier parts of the lung and the diaphragm to function more effectively. This is achieved by blocking off parts of the lung that are most affected by emphysema, using one of several techniques, including the placement of one-way valves, coils, or biological glues via a bronchoscope. These devices are designed to redirect air away from diseased parts of the lung to healthier areas, improve the mechanics of breathing, and facilitate the removal of trapped air and secretions.

Indications

BLVR is indicated for patients with advanced emphysema who have symptoms that are poorly controlled by medical therapy, including bronchodilators, corticosteroids, and oxygen therapy. Candidates for this procedure typically have heterogeneous emphysema, where some lung areas are more affected than others, and have preserved their exercise capacity to some extent. Patients must undergo thorough pre-procedural evaluation, including pulmonary function tests, computed tomography (CT) scans of the chest, and sometimes cardiopulmonary exercise testing to determine their suitability for BLVR.

Techniques

Several techniques are used in BLVR, each with its specific indications, advantages, and limitations:

Endobronchial Valves

Endobronchial valves are the most widely used devices for BLVR. They are one-way valves inserted into the airways that allow air to exit but not re-enter the treated lung segment, leading to its collapse and volume reduction. This technique requires the absence of collateral ventilation between the target and adjacent lung segments, which is assessed through specialized imaging techniques or during the procedure itself.

Bronchial Coils

Bronchial coils are nitinol wires that are inserted into the airways, where they assume a coiled shape. They cause fibrosis and volume reduction of the treated lung areas. Coils can be used in patients with collateral ventilation and are not dependent on the presence of intact interlobar fissures.

Biological Glues

Biological glues, such as polymeric lung sealants, are injected into the airways leading to the diseased lung areas. They induce an inflammatory response, resulting in the scarring and closure of these areas, thereby reducing lung volume.

Risks and Complications

As with any medical procedure, BLVR carries risks and potential complications. These may include pneumothorax (collapsed lung), exacerbation of COPD symptoms, pneumonia, bronchitis, and, in rare cases, death. The risk of complications varies depending on the technique used and the patient's overall health.

Outcomes

Studies have shown that BLVR can lead to significant improvements in lung function, exercise capacity, and quality of life in selected patients with emphysema. However, the benefits must be weighed against the potential risks and complications of the procedure.