WO2017053935A1

WO2017053935A1 - Expandable structure to treat hyperinflated lung

Info

Publication number: WO2017053935A1
Application number: PCT/US2016/053693
Authority: WO
Inventors: Benjamin David BELL; George Bourne; Mark Gelfand; Jianmin Li
Original assignee: Soffio Medical Inc.
Priority date: 2015-09-25
Filing date: 2016-09-26
Publication date: 2017-03-30

Abstract

Implantable airway bypass device 150 that relieves trapped air in the lung of a patient having restricted ventilation. The device comprises a conduit that approximately spans the distance of the chest wall, an air intake component (i.e. an open end of a conduit), and a surrounding expandable structure, which further comprises a basket (160) and a neck to surround the air intake component within a voided space in lung tissue, created, and defined by the expandable structure. The expandable structure may bey formed of at least one wire which forms the neck and the basket. The device may further comprise a membrane over at least a portion of an outer surface of the basket and an outer surface of the neck portion.

Description

EXPANDABLE STRUCTURE TO TREAT HYPERINFLATED LUNG

BACKGROUND

[oooi] The present invention is directed generally to implantable medical devices to improve chest mechanics in diseased patients by partially bypassing natural airways. The methods and devices disclosed herein may be configured to create alternative expiratory passages for air trapped in the emphysematous lung by draining the lung parenchyma, thereby establishing communication between the alveoli and/or other spaces with trapped air and the external environment.

[0002] Improvements over previous devices may include less invasive treatment, avoiding surgery and large area pleurodesis, minimizing disturbance and irritation of lung tissue to minimize inflammation or damage to untargeted areas of the lung and chest, better control of healing processes, and establishing long-term patency of artificial air passages.

[0003] Diseases of the lung such as Chronic Obstructive Pulmonary Disorder (COPD), emphysema, chronic bronchitis, and asthma may manifest with abnormally high resistance to airflow in an air pathway of the respiratory system. Homogeneous obstructive lung disease, also known as diffuse lung emphysema, is particularly difficult to treat and currently has few treatment options. Patients with pulmonary emphysema are unable to exhale appropriately, which leads to lung hyperinflation, which involves air trapping or excessive residual volume of air trapped in at least a portion of the lungs. The debilitating effects of the hyperinflation are extreme respiratory effort, the inability to conduct gas

exchanges in satisfactory proportions, severe limitations of exercise ability, and a sensation of dyspnea and associated anxiety. Although optimal pharmacological and/or other medical therapies work well in the earlier stages of the disease, as it progresses, these therapies become increasingly less effective. For these patients, the standard of care is surgical treatment involving lung volume reduction surgery, lung transplantation or both.

[0004] It has been observed in prior art and is generally accepted by clinicians that respiratory impairment in emphysema has an important 'mechanical' component. Destruction of pulmonary parenchyma causes compounding disadvantages of a decreased mass of functional lung tissue decreasing the amount of gas exchange, and a loss in elastic recoil and hence the inability to equally or substantially completely exhale the same amount of air that was inhaled on the previous breath. This leads to the typical hyper-expansion of the chest with a flattened diaphragm, widened intercostal spaces, and horizontal ribs, resulting in increased effort to breath and dyspnea. When the destruction and hyper-expansion occur in a non-uniform manner, the most diseased lung tissue can expand to crowd the relatively less diseased or even normal lung tissue further reducing lung function by preventing optimal ventilation of the less diseased or normal lung. Lung volume reduction surgery (LVRS) and the surgical removal of the most affected lung regions conceptually would allow the relatively spared part of the remaining lung to function in mechanically improved

conditions.

[0005] Some prior art relating to the mechanical approaches to emphysema addresses the opportunity presented by this non-uniform parenchymal

destruction: potential removal of fluid or air from the parts of the lung most effected by the disease, while allowing the remaining lung to function normally, e.g., expand in a satisfactory manner, and improve the overall elastic recoil of the chest cavity. However, these previously proposed approaches have shown difficulties with long term device performance and viability, for example, caused by unintended tissue ingrowth, occlusion by naturally occurring secretions (e.g. mucus or other secretions resulting from the heightened pro-inflammatory state in COPD), excessive bleeding, complications from device delivery, or eventual device rejection by the body.

SUMMARY

[0006] Systems, methods and devices have been conceived and are disclosed herein for improving the mechanics of a diseased lung of a patient by implanting one or more airway bypass ventilation devices in a lung. For example, the patient may suffer from COPD, emphysema, chronic bronchitis, or asthma. An airway bypass device may comprise a device for connecting a volume of lung

parenchyma affected by abnormally high resistance airways to a secondary location (e.g. atmosphere.)

[0007] Furthermore, devices and methods have been conceived and are disclosed herein for reducing residual lung volume and hyperinflation. Reducing lung hyperinflation may help relieve the associated symptoms of dyspnea and anxiety. The devices and methods may be configured to create an empty space or void in which the implant is placed, to minimize tissue damage and

inflammation in the area surrounding the implant, and controlling the healing processes at the implant site in a manner such that the device patency may be sufficiently maintained for the life of the device. One rudimentary measure of device patency, is the maintenance of the empty volume in which the implant is placed, which acts to reduce the potential occlusion of the device. While device occlusion and tissue ingrowth represent some of the many challenges to maintaining patent airways, the present devices and methods may also be configured to allow selective healing and tissue growth to commence in a controlled manner to benefit implant security and function in a manner that does not adversely affect device performance over a long term.

[0008] A device to allow the bypass of the airways of a diseased lung has been conceived and is disclosed herein. The device comprises comprise a conduit that approximately spans the distance of the chest wall, an air intake component (i.e. an open end of a conduit), and a surrounding expandable structure, which further comprises a basket and a neck to surround the air intake component within a voided space in lung tissue, created, and defined by the expandable structure. The conduit may comprise at least one hollow lumen fluidly connecting the intake component and space occupied by the expandable structure. The device may allow for the relief of symptoms associated with certain lung diseases by allowing fluid to escape the lung to an area of lower pressure.

[0009] A method and device for treating hyperinflated lungs has been conceived and is disclosed herein comprising, for example, creating a space within the lung, connecting that space to a larger volume of the lung through mechanisms including collateral ventilation, and providing an airway bypass pathway from the space to a lower-pressure space (e.g. atmosphere). Air flow may naturally occur if flow resistance of the airway bypass pathway is sufficiently low. In some instances, further improvements may be present to maintain the space within the lung, to minimize tissue ingrowth and to prevent device occlusion and failure over the lifetime of the implant. In addition, reduced dimensions, minimized local trauma and other advantageous characteristics may result from the novel design and uses of the device.

[oooio] Advantages of the device described herein may also affect aspects of device delivery, function and use, and may include specific advantages described herein envisioned at least to assist in device delivery, voided space creation and maintenance, minimize tissue irritation, minimize device occlusion, reduce inflammation, and minimize friction between the device and lung

parenchyma, and improve the overall effectiveness of the airway bypass device.

BRIEF DESCRIPTION OF THE DRAWINGS

[oooi i] Figure 1 is a combined illustration of chest anatomy showing the basic schematics of an airway bypass device implanted in a lung.

[00012] Figure 2A provides a top view of an expandable structure, illustrating the single-wire basket formed of a continuous weave.

[00013] Figure 2B provides a side view of an expandable structure, illustrating the single-wire basket formed of a continuous weave, with the membrane limiting the exposure of any wire terminuses.

[00014] Figures 3A and 3B are illustrations of an expandable structure with internal cells pitched in the lateral direction.

[00015] Figures 4A and 4B are illustrations of an expandable structure with internal cells pitched in the vertical direction.

[00016] Figure 5 is a schematic showing an airway bypass device with a membrane applied to the base of the expandable structure.

[00017] Figure 6 shows an illustration of one envisioned port and basket device, showing an additional tilted catheter tip providing additional access to the internal volume of the expandable structure.

[00018] Figures 7A-E show additional ingrowth features that may help to anchor the expandable structure or promote tissue ingrowth. DETAILED DESCRIPTION

[00019] Systems, methods and devices are described herein for improving the mechanics of a diseased lung 100 of a patient by implanting an airway bypass device 150 that relieves pressure within the lung 100. The method and device may comprise an implantable device, or a partially implantable device configured to create a cavity or voided space in lung parenchyma 106, to connect the lung volume accessed through the cavity or voided space 170, to transport fluid (e.g. air) from a position within the cavity to a second position (e.g. atmosphere) of lower pressure, and to minimize undesired effects (e.g. tissue regrowth) that may interfere with device performance.

[00020] Certain diseases, including COPD, are characterized by slow or inefficient flow of gas, e.g., air, exiting and emptying of alveoli. The air becomes trapped in the lung, with new breaths initiated before the exhalation of

substantially all of the air inhaled on the previous breath. An abnormally high amount of air is withheld in the lung, for example in the alveoli and alveoli ducts and bronchioles. These small air filled cavities are within the smallest divisions of the lung and form areas of increased resistance to airflow that result in reduced lung expiration. Fluid communication within the lung enables the improvement of the mechanics of a diseased lung, allowing entire lobes or entire lung to empty trapped air through one or more artificial channels.

[00021] In relation to COPD, the term 'emphysema' is generally used in a morphological sense, and can be diagnosed using current imaging technology. In particular, high resolution computed tomography (HRCT) is a reliable tool for demonstrating the pathology of emphysema, even in subtle changes within secondary pulmonary lobules. Among these morphologic changes to lung parenchyma 106, a particular pattern of destruction of the lung parenchyma 106, commonly referred to as pulmonary emphysema, is defined as "an abnormal permanent enlargement of the air space distal to the terminal bronchioles, accompanied by destruction of the alveolar walls, and without obvious fibrosis". While this pattern of destruction poses obvious dimensional challenges, it also creates an opportunity for therapy with the goal of reducing air trapping in these terminal airways. These areas of the lung 100 exhibit dramatically increased natural collateral air flow and in the presence of low density, poorly vascularized areas of the lung 100 where it may be feasible to create a space 170 (i.e. a void or cavity) to collect air without a serious risk of bleeding or device failure due to closure (e.g. occlusion) by tissue ingrowth or scar tissue. This is expected since poor vascular blood supply results in less aggressive tissue growth in response to the initial injury.

[00022] One envisioned method comprises creating a space 170 in at least one area of a lung that may be fluidly connected to a larger volume of the lung through a natural phenomenon called collateral ventilation, wherein air in the larger volume can flow to the created space. The exact mechanism of collateral ventilation is somewhat unclear and often debated, but its effect on pockets of air within unhealthy lung provides a connection to otherwise inaccessible lung tissue. Candidate air pathways for collateral ventilation include the interalveolar pores of Kohn, the bronchioloalveolar communications of Lambert, and the interbronchiolar pathways of Martin. An airway bypass device 150 may allow air to escape from the relatively small space created in the lung and thus relieve air trapped in the larger volume of lung that is connected to the space by collateral ventilation. Furthermore, devices and methods are disclosed for relieving hyperinflation of a lung with restricted air flow, for example due to COPD, emphysema or chronic bronchitis, and relieving symptoms of dyspnea and anxiety and improving quality of life.

[00023] A device and method of treatment have been conceived that allow auxiliary ventilation of a lung (e.g. enhanced, more complete or faster exhalation, pressure relief, reduction of residual volume) from small air-filled spaces where air is trapped. In at least one aspect, the bypass device and method may allow air to pass from a first position within the lung to a second position. The first position may be an area of the lung that has higher pressure relative to the atmosphere at the end of a natural expiration period of the breath. The second position may be the atmosphere (e.g. a vent or other exit mechanism may be positioned on the surface or outside of a patient's body). Alternatively, the second position may be within the natural airways of the patient's pulmonary system that has an air pathway to atmosphere that is less restricted, for example, at a location within the lung or bronchus.

[00024] The device comprising an air intake section may also be placed based on anatomical position. For example, the device may be placed in a specific portion of a patient lung, such as an upper lobe of a lung. The delivery (i.e.

access) location may be chosen for placement of the device (including the external portions of the device) based on factors such as low tissue density, low blood flow, trapped air, presence of a bulla, or depth. The implanted parts of the device comprises a section connected to the air intake that fluidly connects the internal lung to the external atmosphere. The fluid connection between the external atmosphere and the internal lung may also be used to deliver drugs in the opposite direction, into the distal-most areas of the lung, which are

considered the most inaccessible, but where such drugs would be most effective. [00025] An embodiment of the present invention is shown in FIG. 1. FIG. 1 is a schematic illustration of various layers of a patient rib cage and thoracic cavity. Beneath the skin 105 is a rib cage formed by a vertebral column, ribs 101 , and sternum 103. The rib cage surrounds a thoracic cavity, which contains structures of the respiratory system including a diaphragm 104, trachea 109, bronchi 1 10 and lungs 100. An inhalation is typically accomplished when the muscular diaphragm 104, at the floor of the thoracic cavity, contracts and flattens, while contraction of intercostal muscles 102 lift the rib cage up and out. These actions produce an increase in volume, and a resulting partial vacuum, or negative pressure, in the thoracic cavity, resulting in atmospheric pressure pushing air into the lungs 100, inflating them. In a healthy person, an exhalation results when the diaphragm 104 and intercostal muscles 102 relax, and elastic recoil of the rib cage and lungs 100 expels the air. In a patient having a disease such as COPD, emphysema, or chronic bronchitis a restriction in air pathways may cause resistance to air flow and impede the ability of air to be expelled, in at least a portion of the lungs 100, upon muscle relaxation and elastic recoil of the rib cage. The inability to expel air from the restricted portion of the lung may result in a need for increased physical exertion to expel the air, increased residual volume, barrel chest syndrome, or feelings of dyspnea and anxiety. Lung parenchyma 106 is the tissue of the lung 100 involved in gas transfer from air to blood and includes alveoli, alveolar ducts and respiratory bronchioles.

[00026] In human anatomy, the pleural cavity is the potential space between the two pleurae 107, 108 of the lungs, namely the visceral 108 and parietal 107 pleurae. A pleura is a serous membrane which folds back onto itself to form a two-layered membrane structure. The area between the two pleural layers is known as the pleural cavity and normally contains a small amount of pleural fluid. The outer parietal pleura 107 is attached to the chest wall 1 1 1 . The inner visceral pleura covers 108 the lungs 100 and adjoining structures, via blood vessels, bronchi and nerves.

[00027] The pleural cavity, with its associated pleurae 107, 108, aids in the optimal functioning of the lungs during breathing. The pleural cavity also contains pleural fluid, which allows the pleurae 107, 108 to slide effortlessly against each other. Surface tension of the pleural fluid also leads to close apposition of the lung surfaces with the chest wall. This relationship allows for greater inflation of the alveoli during breathing. The pleural cavity transmits movements of the chest wall to the lungs, particularly during heavy breathing. This occurs because the closely apposed chest wall transmits pressures to the visceral pleural surface and hence to the lung.

[00028] It is conceived and disclosed herein that, for example, a therapy would comprise the connection the lung parenchyma to the atmosphere by passing through both layers of pleura. An air or fluid intake component may form the opening or apertures to connect to a conduit 161 that contains at least one hollow lumen 169 of an airway bypass device 150 implanted in the lung

parenchyma 106. It is envisioned in at least one embodiment that the bypass device spans the chest wall and terminates at a position on the external surface of the patient's skin 105. The inner volume may be connected to the surface by a conduit 161 that passes out of the lung through a fused region (i.e. pleurodesis 1 12) between the visceral pleura 108 and parietal pleura 107, passes beneath the skin 105 and exits the skin. Air or other fluids may pass through from the internal lung and exit the device externally. The conduit 161 may be coaxial to and contained within a cuff 174 that forms a sheath over the conduit. The end of the cuff extending to the outer chest wall, e.g., skin, may connect to an annular disc or flange 175 that seats on the skin of the chest and provides an air outlet to exhaust air from the lung to pass through the expandable structure 164, the neck 155, conduit 161 and out to the atmosphere.

[00029] As shown in FIG. 1 , the implanted portion of an airway bypass device 150 may comprise an expandable structure 164 comprising a basket 160 and a neck 155 (i.e. formed of scaffold, cage, weave) that may surround the opening to a conduit 161 that is fluidly connected to the external atmosphere. While other delivery methods may be used, To reduce the overall trauma, which may result from device delivery, it is envisioned that the expandable structure 164 is deployed into the lung in a compressed state, which when deployed creates an empty void or air collection space 170 within lung parenchyma 106. In its deployed state, the expandable structure 164 separates the lung parenchyma from contact with the opening to a conduit 161 of the airway bypass device. The structure 164 defines a volume around the perimeter of the space with an area substantially greater than the area immediately surrounding the openings, apertures, or ports leading into the conduit. These expanded dimensions help maintain airflow from lung parenchyma to the space within the expandable structure 164.

[00030] The basket 160 of the expandable structure 164 may form the exterior of expandable structure 164 and is configured for implantation within lung tissue. This basket 160 of the expandable structure may be made from a bio-compatible or absorbable, flexible material such as Nitinol, stainless steel, silicon, Pebax, PEEK, polypropylene, a composite of multiple materials or other bio-compatible or absorbable materials, such as polymers with these characteristics. In one embodiment, it is envisioned that at least the basket 160 or the neck 155 of the expandable structure 164 may formed of a dissolvable or bio-absorbable material. It is envisioned that, once dissolved, the structure would leave behind a similarly sized space 170 devoid of tissue. The surface of the basket or neck may also be coated with a medicine, chemical or other substance to allow the coating to contact the nearby lung tissue 106. It is envisions that this coating may help to provide therapy (e.g. steroid, antibiotics, other drugs) or prevents reduce, and impedes tissue growth surrounding and into the expandable structure 164.

[00031] The woven structure may form the basket (or other similar shapes e.g. cage, mesh, stent, etc.) that can be delivered in a reduced, undeployed state and expanded to a deployed state having an increased volume. It is envisioned that in at least one envisioned embodiment, the expandable structure 164 comprises a basket that may be deployed into a substantially spherical deployed state. The neck of the expandable structure 164 may extend from the basket, but in at least some embodiments, may extend fully or partially into the chest wall. In another envisioned embodiment, the dimensions and shape of the basket and neck that form the expandable structure may vary, as needed.

[00032] In at least one envisioned embodiment, the expandable structure 164 of the device is formed of narrow, woven Nitinol filaments. In these weaves, the wire 190 begins and terminates at the base of the device facing the chest wall, with some wire 190 overlapping the terminuses. In some embodiments, it may be advantageous for the weave to terminate along the neck of the expandable structure. In addition, weave construction with overlapping wire 190 strands may be preferred for forming not only the basket, but also the entire expandable structure 164, as any non-uniform structure may increase the risk of tissue irritation or inflammation that could accelerate undesired tissue regrowth.

[00033] In other instances, the wire 190 could be formed on a mandrel. In an alternative embodiment, the expandable structure could be chemically milled or photo etched, joined or welded on a single end. In yet a further embodiment, the wire (e.g. polymer, metal, Nitinol, etc.) may be laser cut. In some instances, methods requiring little or no heating may be preferred and result in the

production of a wire of greater consistency and durability. In some cases, all welds or junctions located at the opening or base of the expandable structure 164 may be wrapped in a membrane 172 that causes minimal trauma to local tissue. In embodiments where portions of the expandable structure are formed of stainless steel or Nitinol, a single continuous wire 190 may be advantageous in allowing electrical conduction for radio frequency (RF) applications (e.g. to facilitate device cleaning or extraction).

[00034] In certain embodiments, as shown in FIGS. 2A and 2B, the basket and neck may be formed of a single filament or single wire 190 in the form of a weave, and is therefore envisioned to be free of kinks, junctions, and welds. As such, the surfaces, where contact with lung tissue is made, may be smooth and cause reduced trauma to the surrounding parenchyma. Filaments free from these forms are also uniform, less brittle and less prone to structural failure. To further enhance the atraumatic properties of the expandable structure 164 it may be advantageous to infuse or coat the filaments and other areas in contact with lung tissue with drugs, materials or lubricants to reduced local inflammation and facilitate device delivery.

[00035] Specifically, FIG. 2A show the top view of an expandable structure 164 with only the basket visible. The expandable structure 164 forms a voided space 170 within the lung tissue and contains at least the air intake of the airway bypass device. The basket 160 is formed from a single wire 190 that is woven along the exterior of the basket diameter and is continuous and of uniform thickness. The single wire 190 is formed into the basket 160 and the neck 155 of the expanded structure 164. The single wire may extend between the proximal end 194 of the basket near the neck to the distal end 196, wherein the ends are with respect to an axis 185 of the expanded structure. At the proximal and distal ends, the wire has sections 198 that are bent into turns having relatively small radii of curvature to allow the wire to turn back towards the opposite end of the basket. Other sections 199 of the wire at the proximal or distal end of the basket have a larger radii of curvature, e.g., a shallower bend, than do the sections 198 with the sharper bend. The wire sections 200 away from the proximal and distal ends may have a shallow curvature that corresponds to the outer shape of the basket. The shallow curvature of sections 200 may be greater than the curvature of any of the wire sections 198, 199 at the distal or proximal ends of the basket. Further, the wire near the distal end of the basket includes sections 202 that bend relatively sharply to turn the wire back towards the basket. Other sections 204 of the wire pass through the distal end and extend to and form the neck 155.

[00036] While a single wire is shown in Figures 2A and 2B as forming the basket and neck, it is also within the scope of the invention that the basket and neck be formed of multiple wires. Further, the maximum curvature, e.g., section 198, of the wire 190 is not so great as to form a sharp kink or corner that might cut into lung tissue. In addition, a benefit of the single wire is to avoid more than two ends of a wire that might be exposed to lung tissue and to avoid joints at ends of wires that could weaken the basket. In the single wire 190 embodiment, the ends of the wire may be both arranged at the neck 204 where the ends may be embedded in the conduit or other structure and thus not exposed to lung tissue.

[00037] In embodiments where the expandable structure 164 is formed of a basket 160 and neck 155, a portion of the wire 190 must loop several times to form the basket 160 while other portions of the wire 190 form the neck in one continuous weave. In addition, the points at which the single-wire weave terminates cannot be seen from the view shown in FIG. 2A. In some

embodiments, it is envisioned that the weave terminate along the neck 155, near the base, or on the proximal end of the expandable structure 164. In some instances, the terminal point of the expandable structure 164 is envisioned located in a position that minimizes contact with lung parenchyma. The terminal points may also be partially or fully contained within a flexible membrane 172 to reduce tissue irritation and local inflammation that might results from contact with the edges of the end or ends of the single-wire weave. In the embodiment shown in FIG. 2B, the membrane 172 fully covers the neck 155, but may only partially covers the basket 160 of the expandable structure or cover the entire outer basket.

[00038] The membrane may have openings 183 that overlap one or more cells 180 of the basket. The openings allow air to enter the volume within the basket and thereby flow out the intake conduit 161 to the atmosphere. The openings 183 may be formed in the membrane before the basket is implanted in a patient. The cells may also be formed after the basket is implanted in the lung such as by accessing the interior of the basket via the intake conduit 161 with a probe and pushing the probe through the membrane and between the wires forming the basket. By creating new openings 183 in the membrane, the air passages can be increased from the lung into the basket long after the basket has been implanted, such as one month, six months or years after implantation.

[00039] Additionally, if Nitinol or other flexible materials are used in the construction of the expandable structure 164, the resulting basket may generally expand to form a pre-determined spherical shape. The dimensions of the neck of the expandable structure remain generally unaltered during device deployment. Shape-memory properties of some materials will allow specific or further complex shapes to be formed. In addition, the use of a shape-memory material, such as Nitinol, allows the expandable structure 164 to be highly compressed while maintaining the integrity of structure upon expansion. In some envisioned embodiments and methods, alternative or reduced dimensions may be

advantageous in reducing the dimensional requirements for delivery and deployment. That is, these specialized baskets may help to minimize the required incision size and mitigate the trauma associated with device implantation.

[00040] For instance, the basket may be configured to enter the lung 100 at a deflected pitch in its collapsed state in order to reduce the overall length requirements of delivery in the undeployed or compressed state. In this envisioned embodiment, the deployed expandable structure 164 would be positioned normal (i.e. perpendicular) to the chest wall when fully deployed, while perpendicular depth within the lung would be significantly reduced in its

undeployed state. The expandable structure 164 may be specially configured to reduce the depth needed to accommodate the device in its undeployed state to allow for device placement in various locations in parenchyma.

[00041] In addition to delivery at an angle, in one envisioned embodiment, the expandable structure 164 may also be formed of a single-strand weave that is dimensioned with each strand of the weave at a relative pitch compared to strands that are oriented in the opposite direction.

[00042] That is, the wire 190 strands that form a cell 180 of the weave may be configured in a non-normal orientation. The angle of the single-wire weave may also play a role in the resulting dimensions of a compressed structure.

Specifically, as seen in FIGS. 3A and 3B, it may be possible to compress a pitched (e.g. horizontally pitched) basket further than a basket with a normal- pitched weave. As shown in FIGS. 3A, each cell 180 of the basket 160 of the expandable structure 164 comprises four sides, formed of a continuous single- wire weave. Two of the corners, opposite to each other in the direction of the axis 185 of the expanded structure 164, may have cell angles 181 less than 90 degrees, less than 80 degrees or less than 75 degrees, if the desire is for the expandable structure to collapse into a narrow diameter and pass through a narrow conduit. In particular, the configuration of the wire 190 of the basket 160 results in a compressed basket, like the one shown in FIG. 3B. In FIG. 3B the length, L, of the basket 160 is greater than, while the width, W, is less than the respective length and width of a basket 160 with a substantially normal (i.e.

perpendicular) wire configuration. This configuration may be advantageous when a reduce width is desired; specifically, a reduced width is desired to minimize the incision required to deliver the device to the internal lung.

[00043] When it is desired to minimize the length, L, of the compressed basket 160, it is envisioned that a pitch, such as the one illustrated in FIGS. 4A and 4B may be used. As in FIGS. 4A and 4B, it may be possible to reduce the length of the compressed basket with a pitched (e.g. vertically pitched) basket further than a basket with a normal-pitched weave. FIG. 4A shows each cell 180 of the basket 160 of the expandable structure 164 comprising four sides, and formed of a continuous single-wire weave. However, in this embodiment, the two corners that are situated on the horizontal axis have cell angles 181 greater than 90 degrees, greater than 100 degrees or greater than 120 degrees. In FIG. 4B, as a result, the length, L, of the basket 160 is less than, while the width, W, is greater than the respective length and width of a basket 160 with a substantially normal (i.e. perpendicular) wire configuration. A deflection of the basket at the angle relative to the chest wall may also be used to reduce the overall depth of penetration into the internal lung parenchyma during device delivery. Similarly, other customized basket dimensions and shape may be used even if the resulting structure may have non-spherical or reduced volume when fully deployed.

[00044] As one of the advantages of the expandable structure 164 is to maintain a larger surface area and volume to conduct fluid from the lung, it may be advantageous in some embodiments to reduce any undesired tissue ingrowth that would reduce the working surface area or volume, especially in into the voided space created by the structure 164. Also, friction, local irritation, and inflammation may increase tissue granulation and growth, which may have a direct effect on device patency and may adversely affect device performance. The physical separation of lung parenchyma 106 from the conduit 161 and the one or more openings leading into the conduit 161 can help to address

granulation and general inflammation. Separation also helps to minimize the risk of occlusion that may result from the growth of new tissue into or over any port that lead into the conduit 161. In certain instances, it is envisioned that the expandable structure 164 should maintain a minimum overall size and volume in order to effectively prevent or deter tissue growth that may occlude or partially occlude the conduit 161 or any other component within the structure. While it may be exceedingly difficult to prevent all tissue ingrowth, preventing or mitigating undesired tissue ingrowth may provide important advantages in certain embodiments of the device.

[00045] In at least one embodiment, it is envisioned that the expandable structure 164 may be covered by a material or membrane 172. In some aspects, the membrane may be partially visible and cover one or more portions of the expandable structure 164. In some embodiments, it may be preferred that contact between the base of the basket and the chest wall 1 1 1 be minimized with the use of a membrane 172. The membrane 172 may not only be employed at the base of the basket 160 to reduce local irritation and inflammation, but also in a similar fashion to surround, or partially surround any portion of the basket or neck of the expandable structure 164.

[00046] In one envisioned embodiment, the material or membrane 172 coverage encapsulates roughly one or more hemispheres or portions of the basket. In a further embodiment, a dome covering the top portion of the expandable structure 164 prevents or deters tissue growth onto the components within the structure. In particular, this membrane 172 may be advantageous given the potential contact the component makes with lung parenchyma 106.

[00047] During deployment, a membrane layer 172 may surround one or more hemispheres of the basket to reduce tissue injury or irritation by increasing tissue contact surface area, as compared to tissue contact with the expandable structure 164 or basket without a membrane layer. Also, increased tissue contact surface area reduces stress concentration or pressure on tissue by spreading force over a larger area. As such, during deployment, a membrane 172 may reduce the so-called "cheese wire effect" wherein one or more filaments may pass through tissue instead of pushing tissue away. A membrane 172 may facilitate creation of a cavity 170 within the deployed basket and may reduce risk of tissue passing through filaments into the cavity as the cage is deployed.

[00048] Alternatively, a chest-wall facing membrane 172 would limit contact between the basket of the expandable structure and the inside of the chest wall 1 1 1. This may be especially advantageous in embodiments in which the basket 160 is free floating or only partially secured internally within the lung 100. In these instances, the volume of the expandable structure 164 acts to anchor the device within the lung 100, which may result in increased contact between the device and the internal chest wall 1 1 1. It is envisioned, as shown in FIG. 5, that the basket 160 may be covered (e.g. along the chest facing portion or

hemisphere) with a membrane 172 (e.g. terminating at an edge 182 between the proximal end 194 of the basket and the equator 195 which is at the section of the basket having the largest area in cross section) that may allow the device to float freely within the lung parenchyma, prevent contact with the internal chest wall, and/or minimize local irritation against chest tissue. The membrane may extend the distance of the neck 155 surrounding the conduit 161 of the device up to the chest wall 1 1 1 . By freely floating along the distance, d, the basket 160 and neck 155 of the expandable structure 164 may be able to rise and fall with the expansion of the lung 100. One or more membrane layers 172 may also help to dampen the movement of the implanted device from that may occur, for example through impact, coughing or sneezing.

[00049] A membrane layer 172 covers at least a portion of the outer surface of the basket 160. The membrane may contribute to the stability of the structural mechanics of the basket and the overall expandable structure 164. For example, a membrane 172 may contribute to structural stability, sheer strength, or hoop strength of a deployed expandable structure 164, which may further support the woven basket or relieve some structural function from a woven basket.

[00050] In at least one aspect, it is envisioned that the membrane covering the expandable structure 164 may be clear or partially visible. In a further

embodiment, the material or membrane 172 may also be permanent, removable, bio-degradable, dissolvable or absorbable. The membrane may be formed of or contain a material or chemical that prevents, reduces, or impedes tissue growth. At least one envision membrane may be infused with therapeutic agents including antibiotics, steroids, or drugs that may be delivered to the lung. In at least one further embodiment, the membrane may be selectively permeable to allow the passage of gas (e.g. air) while restricting tissue ingrowth. One or more membrane layers may also help to facilitate deployment of the expandable structure 164 into lung parenchyma by reducing the friction and resistance of tissue against the expandable structure 164.

[00051] Further, membranes use may serve a variety of functions in different embodiments of the device. In certain embodiments, a membrane may be employed either within or along the exterior of the expandable structure or basket. In one embodiment, it is envisioned that a temporary membrane may be used to control the relative rate of tissue growth to the outer surface of the scaffold of the expandable structure 164. This function may be used, for example, to control or accelerate the healing process or temporarily delay tissue ingrowth. In addition, a partial membrane may be used to secure the device in lung parenchyma or inhibit tissue growth in regions of the expandable structure 164 that are closest to the are immediately surrounding the opens to the conduit 161 , or other components within the structure, where contact with lung tissue may increase the risk of tissue growth bridging to the conduit 161 . In other aspects, a membrane may be needed only temporarily, or only shortly after device deployment to mitigate the initial risk of device occlusion from cells that may have been displaced, as a result of device delivery or deployment.

[00052] In some aspects, tissue growth can be retarded in the presence of the membrane 172. As a result, a membrane layer may also facilitate removal or cleaning of an expandable structure 164. For example, a membrane layer may cover the outside surface of a scaffold structure and be made from a material such as silicone that inhibits tissue attachment or increases lubricity so the expandable structure 164 can be contracted to an undeployed configuration and removed from the lung without pulling on tissue that otherwise may have attached to or entangled in the scaffold. The collapse of the device may be facilitated by the use of a flexible delivery sheath 120 using a reversal of delivery technique. In addition, a membrane layer may facilitate cleaning or maintenance of the device. For example, a membrane made from a lubricious or non-stick material may more easily shed mucus or other debris.

[00053] The expandable structure 164 may be configured, especially when covered with a material or membrane 172, to have a sufficient quantity and sufficiently sized pores, such that the structure of the expandable structure stimulate fibrosis and tissue response and integrate into the tissue. For example, pore size may be between about 3 to 5 mm in diameter, or have a cross- sectional area between about 7 to 20 mm². As shown in FIG. 6, basket,

membrane, pore, and the relative position and size of these features may be customized, as needed. Pore size may be roughly equivalent to the size of a single cell 180 of the expandable structure 164. One or more cells in the area covered by one or more membranes may be remain open, as needed. These features can play an important role in the rate of tissue growth in and surrounding the device. Finally, as illustrated, the membrane 172 may extend to cover any portion or separate portions of the expandable structure 164. The dashed line of FIG. 6 illustrates an alternate end of a membrane 172 that extends over the basket 160 from the neck 155 of the structure.

[00054] The device illustrated in FIG. 6 also an optional cleaning component or vent catheter 165 that may be used to provide additional relief from air, fluid or other materials that may build up within the expandable structure 164. The vent catheter is configured specifically to facilitate fluid removal (e.g. blood, mucus, pleural fluid, etc. It is envisioned that the temporary use and subsequent removal of the vent catheter 165 would not affect the overall performance of the device and is not required for air to vent out of system. The device will continue to allow the passage of air through the system via the conduit 161 in the absence of the catheter 165.

[00055] The expandable structure 164 may be deployed over time in a gradual and controlled manner to aid the healing process and minimize inflammation, bleeding and granulation. For example volume of the space 170 created may be increased gradually over several hours, days or weeks by expanding in small increments until the fully deployed state is reached (e.g., 0.25 to 1.0 ml_ once every few days up to a fully deployed volume between about 3 to 20 ml_ (e.g., about 14 ml_). The expandable structure 164 may be deployed with a balloon (e.g., compliant balloon) inside the expandable structure 164.

[00056] In addition to reducing tissue ingrowth, the purposeful positioning of a membrane 172 or multiple membrane layers may also provide for selective control of tissue ingrowth. That is, while a membrane layer may inhibit ingrowth of tissue by providing a physical barrier to tissue contact, tissue proliferation may continue at selected pores, orifices or where the membrane 172 is altered or not present. While unintended tissue growth can negatively affect airflow and device performance, selective ingrowth can help to secure the expandable structure 164 and other parts of the device within the body. Typically increasing the contact pressure or overall surface area in contact between the tissue and device can act to stimulate tissue ingrowth.

[00057] While various materials and methods have been described for reducing tissue growth in areas around the expandable structure and airway bypass device, in certain embodiments, it may be advantageous to allow and even selectively facilitate tissue growth. Specifically, tissue growth provides a natural approach to forming a flexible and hermetic seal. It may be advantageous to increase the rate of tissue growth where this seal would provide benefits to device function without reducing overall device patency.

[00058] In at least one embodiment, as shown in FIGS. 7A-7E it is envisioned that one or more structures along the basket, neck or other portion expandable structure may act as tissue anchors 184 to secure the device to tissue and facilitate tissue growth. A tissue anchor 184 may be formed using the same or similar materials as the basket and may increase tissue growth in the area surrounding the structure offering increased surface area and contact with lung parenchyma.

[00059] FIGS. 7A-7E show several points along a deployed basket of an airway bypass device 150 where tissue ingrowth may be accelerated. The selection of anchor 184 location plays an important role determining the benefits of the specific tissue growth. In some embodiments, if the distal end of the basket is secured to with lung parenchyma by tissue growth, it is envisioned that the device may be more secure and capable of withstanding sudden or forceful movements (e.g. from coughing, sneezing, impact, etc.). Generally, however, the elasticity of tissue, in combination with the inherent flexibility of the basket or expandable structure 164 may provide an overall dampening effect against otherwise traumatic event that may affect the implanted device.

[00060] As a result of their design, tissue anchors 184, increase tissue ingrowth by increasing two important factors that increase cell proliferation: contact and surface area. Specifically, FIGS. 7A and 7B show tissue anchors that extend away from the basket 160 and may enter the surrounding lung parenchyma 106. Therefore, it is envisioned that these anchors may increase the fixation of the expandable structure 164, which results in an increased level of contact, and also increase the surface area available to tissue ingrowth. The embodiment shown in FIG. 7C shows a tissue anchor that is formed of filament similar to the anchor of FIG. 7A. But, as the orientation of these anchors 184 does not extend outward, the mechanism for promoting tissue ingrowth is simply an increase in available surface area. Finally, embodiments like those illustrated in FIGS. 7D and 7E are shaped to provide fixation into the lung parenchyma 106. The increased contact with surrounding lung tissue 106, results in the increased tissue ingrowth over time.

[00061] In certain embodiments, tissue anchors 184 and may be found in one or more positions along the neck of the expandable structure 164. In further embodiments, tissue anchors 184 may be placed in contact with the internal chest wall or along the ingrowth cuff 174 of the device. The increased surface area offered by these features (e.g. anchors 184) and increased tissue contact may be sufficient to accelerate tissue ingrowth. In addition to promoting selective tissue ingrowth, tissue anchors 184 placed proximally along the device may also accelerate tissue growth that assists in hermetically sealing the device from the external environment. In addition to providing improved elasticity and motion dampening, the self-healing properties of tissue ingrowth facilitated by the anchors 184 makes a seal formed by tissue ingrowth far less likely to experience failure or leakage.

[00062] In some instances, the device may be configured with radiopaque areas to allow imaging technology to assist in assessing if the device is implanted satisfactorily. Imaging may also be used during and following the steps of implanting the device to facilitate the proper placement of the device. Imaging technology such as x-ray or fluoroscopy may be used to image radiopaque markers placed on the device, for example on the expandable structure 164.

[00063] While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. It is important to note that, while the order or arrangement of the components might be interchangeable, there may be an arrangement or multiple arrangements that are advantaged, as described. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s).

[00064] In this disclosure, the terms "comprise" or "comprising" do not exclude other elements or steps, the terms "a" or "one" do not exclude a plural number, and the term "or" means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.

Claims

CLAIMS: The invention is:

1. A device for airway bypass of a diseased lung comprising: an expandable structure (164) configured to be placed in lung tissue and including a neck (155) and a basket (160), wherein the neck region extends from the basket and is connectable to a conduit (161 ) extending through a chest wall (1 1 1 ) and is open to the atmosphere, wherein the expandable structure is formed of at least one wire (190) which forms the neck and the basket.

2. The device of claim 1 wherein the basket has an axis (185), a proximal end region (194) adjacent the neck and a distal end region (196) opposite to the proximal end along the axis (185), and wherein the at least one wire extends back and forth (198, 199, 200) between the distal end region and the proximal end region.

3. The device of claim 1 or 2 wherein at least one wire is arranged to define cells (180) which are adjacent sections (200) of the at least one wire, wherein the cells have opposite corners (181 ) in the direction of axis (185) and the opposite corners define angles of less than or greater than 90 degrees.

4. The device of claim 2 wherein at least one wire defines cells (180) adjacent sections (200) of the at least one wire, wherein the cells have opposite corners (181 ) along the direction of the axis (185) and the opposite corners define angles of less than 90 degrees, less than 80 degrees or less than 75 degrees.

5. The device of claim 2 wherein at least one wire defines cells (180) adjacent sections (200) of the at least one wire, wherein the cells have opposite corners (181 ) along the direction of the axis (185) and the opposite corners define angles of greater than 90 degrees, greater than 100 degrees or greater than 1 15 degrees.

6. The device of any of claims 1 to 5 wherein the at least one wire is a single wire.

7. The device of any of claims 1 to 6 wherein the at least one single wire includes bends (198, 199) at the distal end region and at the proximal end region, wherein a radius of curvature of the bends at the distal end region and the proximal end region is greater than a radius of curvature of sections (200) of the single wire extending between the proximal and distal ends.

8. The device of claim 7 wherein the bends at the distal end region or the proximal end region include sharp bends (198) and shallow bends (199).

9. The device of any of claims 1 to 8 wherein the at least one single wire includes at least one section (202) which extends through the proximal end region without passing into the neck and at least one other section (204) which extends through the proximal end region and into the neck.

10. The device of any of claims 1 to 9 wherein the at least one other section (204) forms a loop in the neck such that the wire section twice traverses the neck before returning to the basket.

1 1. The device of any of claims 6 to 10 wherein ends of the single wire are in the neck.

12. The device of any of claims 1 to 1 1 wherein the distal end (196) of the basket includes at least one tissue anchor extending distally of the distal end.

13. The device of any of claims 1 to 12 wherein the expandable structure is expandable from a thin, undeployed state, and to an expanded, deployed state, having an increased volume.

14. The device of any of claims 1 to 13, wherein the expandable structure is one or more of: a cage, a mesh, a basket, a weave, a stent and struts.

15. The device of any of claims 1 to 14, wherein the at least one wire is made from one or more of: Nitinol, stainless steel, silicon, Pebax, PEEK, and one or more bio-absorbable polymers.

16. The device according to any of claims 1 to 15, wherein the

expandable structure is configured to be deployed into a deployed state having substantially spherical, or funnel, or torus, or ovoid, or cylindrical shape.

17. The device according to any of claims 1 to 16, wherein a space in the lung tissue maintained by the expandable structure in a fully deployed state has a volume which is one of:

- from 4 to 1500 cm3,

- from 4 to 180 cm3,

- from 4 to 100 cm3,

- from 10 to 20 cm3,

- from 20 to 50 cm3,

- from 50 to 100 cm3,

- from 100 and 180 cm3,

- from 190 to 300 cm3,

- from 290 to 400 cm3,

- from 390 to 500 cm3.

18. The device according to any one claims 1 to 17, wherein the expandable structure is configured to deliver a biologically active compound.

19. A device for airway bypass of a diseased lung comprising: an expandable structure (164) configured to be placed in lung tissue (106) and including a neck (155) and a basket (160), wherein the neck region extends from the basket and is connectable to a conduit (161 ) extending through a chest wall and open to the atmosphere, and a membrane (172) over at least a portion of an outer surface of the basket and an outer surface of the neck portion.

20. The device of claim 20 wherein the membrane is symmetrical about an axis (185) of the expandable structure.

21. The device of any of claims 19 and 20 wherein the membrane has a distal edge (182) extending around a circumference of the basket and between the neck and an equator (195) of the basket.

22. The device of any of claims 19 and 20 wherein the membrane has a distal edge (182) extending around a circumference of the basket and between an equator (195) of the basket and distal end (196) of the basket.

23. The device of any of claims 19 to 20 wherein the membrane covers an entirety of the outer surface of the basket.

24. The device of any of claims 19 to 23 wherein the membrane includes openings (183) over one or more cells (180) in the basket.

25. The device of claim 24 wherein one or more of the openings are formed after the expandable device is implanted into the lung.

26. The device of any of claims 19 to 25 wherein the basket is arranged as a wire mesh, wherein the mesh defines cells which have opposite corners along the axis (185) of the expandable device and the opposite corners define angles of less than or greater than 90 degrees.

27. The device of any of claims 19 to 26, wherein the expandable structure is expandable from a thin, undeployed state, and to an expanded, deployed state, having an increased volume.

28. The device of any of claims 19 to 27, wherein the basket is one or more of: a cage, a mesh, a basket, a weave, a stent and struts.

29. The device of any of claims 19 to 28, wherein the wire is made from one or more of: Nitinol, stainless steel, silicon, Pebax, PEEK and a biocompatible polymer.

30. The device according to any of claims 19 to 29, wherein the expandable structure is configured to be deployed into a deployed state having substantially spherical, or funnel, or torus, or ovoid, or cylindrical shape.

31. The device according to any of claims 19 to 30, wherein a space in the lung maintained by the expandable structure in fully deployed state or by the scaffolding structure has a volume which is one of: