Abstract:
Methods, systems and devices are provided for performing lung volume reduction in patients suffering from chronic obstructive pulmonary disease or other conditions where isolation of a lung segment or reduction of lung volume is desired. The methods are minimally invasive with instruments being introduced through the mouth (endotracheally) and rely on isolating the target lung tissue segment from other regions of the lung and occluding various lung passageways with the use of occlusal stents. The occlusal stents are delivered with the use of an occlusal stent delivery system which is loaded with the occlusal stent with the use of an occlusal stent loading system.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 12/730,932, filed Mar. 24, 2010, which is a continuation of U.S. patent application Ser. No. 11/280,530, filed on Nov. 15, 2005, which claims the benefit of priority of U.S. Provisional Patent Application No. 60/628,856, filed on Nov. 16, 2004, the contents of each are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to medical devices, systems and methods. In preferred embodiments, the present invention relates to methods and apparatuses for effecting lung volume reduction by aspirating isolated segments of lung tissue. 
     Chronic obstructive pulmonary disease is a significant medical problem affecting 16 million people or about 6% of the U.S. population. Specific diseases in this group include chronic bronchitis, asthmatic bronchitis, and emphysema. While a number of therapeutic interventions are used and have been proposed, none are completely effective, and chronic obstructive pulmonary disease remains the fourth most common cause of death in the United States. Thus, improved and alternative treatments and therapies would be of significant benefit. 
     Lung function in patients suffering from some forms of chronic obstructive pulmonary disease can be improved by reducing the effective lung volume, typically by resecting diseased portions of the lung. Resection of diseased portions of the lungs both promotes expansion of the non-diseased regions of the lung and decreases the portion of inhaled air which goes into the lungs but is unable to transfer oxygen to the blood. Lung reduction is conventionally performed in open chest or thoracoscopic procedures where the lung is resected, typically using stapling devices having integral cutting blades. Although these procedures appear to show improved patient outcomes and increased quality of life, the procedure has several major complications, namely air leaks, respiratory failure, pneumonia and death. Patients typically spend approximately 5-7 days in post-op recovery with the majority of this length of stay attributed to managing air leaks created by the mechanical resection of the lung tissue. 
     In an effort to reduce such risks and associated costs, minimally or non-invasive procedures have been developed. Endobronchial Volume Reduction (EVR) allows the physician to use a catheter-based system to reduce lung volumes. With the aid of fiberoptic visualization and specialty catheters, a physician can selectively collapse a segment or segments of the diseased lung. An occlusal device is then positioned within the lung segment to prevent the segment from reinflating. By creating areas of selective atelectasis or reducing the total lung volume, the physician can enhance the patient&#39;s breathing mechanics by creating more space inside the chest wall cavity for the more healthy segments to breath more efficiently. 
     Additional improvements to EVR are desired. A delivery system is desired which can position an occlusal device within a desired segment of a lung passageway with high accuracy. Such a delivery system should be easy to use, should allow interchangeability of a variety of instruments, and should allow delivery of multiple occlusal devices. It is desired that such delivery of multiple occlusal devices be achieved while maintaining evacuation of a diseased region of the lung. It is also desired to provide a system which utilizes conventional bronchoscopes to deliver the occlusal devices to the lung passageways. Such utilization should be easy to operate and should not interfere with additional therapies which utilize the bronchoscope. At least some of these objectives are met by the current invention. 
     2. Description of the Background Art 
     Patents and applications relating to lung access, diagnosis, and treatment include U.S. Pat. Nos. 6,709,401; 6,585,639; 6,527,761; 6,398,775; 6,287,290; 5,957,949; 5,840,064; 5,830,222; 5,752,921; 5,707,352; 5,682,880; 5,660,175; 5,653,231; 5,645,519; 5,642,730; 5,598,840; 5,499,625; 5,477,851; 5,361,753; 5,331,947; 5,309,903; 5,285,778; 5,146,916; 5,143,062; 5,056,529; 4,976,710; 4,955,375; 4,961,738; 4,958,932; 4,949,716; 4,896,941; 4,862,874; 4,850,371; 4,846,153; 4,819,664; 4,784,133; 4,742,819; 4,716,896; 4,567,882; 4,453,545; 4,468,216; 4,327,721; 4,327,720; 4,041,936; 3,913,568 3,866,599; 3,776,222; 3,677,262; 3,669,098; 3,542,026; 3,498,286; 3,322,126; WO 98/48706; WO 95/33506, and WO 92/10971. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides methods, systems, and devices for performing lung volume reduction in patients suffering from chronic obstructive pulmonary disease or other conditions where isolation of a lung segment or reduction of lung volume is desired. These methods, systems, and devices are likewise suitable for the treatment of bronchopleural fistula. The methods are minimally invasive with instruments being introduced through the mouth (endotracheally) and rely on isolating the target lung tissue segment from other regions of the lung and occluding various lung passageways with the use of occlusal stents. 
     In a first aspect of the present invention, an occlusal stent delivery system is provided for delivering an occlusal stent to a target lung passageway. In preferred embodiments, the delivery system includes a visualization instrument configured for endobronchial advancement into a lung passageway leading to the target lung passageway. The instrument having a proximal end, a distal end, a working lumen extending therethrough, means for visualization near the distal end, and an occlusive member disposed near its distal end which is configured to be expandable to occlude the lung passageway. In addition, the system includes a delivery catheter having a proximal end, a distal end and a receptacle formable within its distal end for loading the occlusal stent therein. The delivery catheter is configured to be advanced through the working lumen of the visualization instrument so that its distal end extends beyond the distal end of the visualization instrument and wherein its distal end is retractable so that retraction of its distal end releases the occlusal stent to the target lung passageway. Typically, the distal end of the delivery catheter has portions of variable flexibility to allow the catheter to be advanced through a potentially curved working lumen without applying forces sufficient to redirect the visualization instrument. 
     In preferred embodiments, the system further includes a clamp connector. In some embodiments, the clamp connector comprises a connector body having a passageway therethrough, and means for connecting the connector body to a visualization instrument having a working lumen so that insertion of an instrument through the passageway of the connector body inserts the instrument into the working lumen of the visualization instrument. In preferred embodiments, the passageway and the working lumen are non-axially aligned during connection. In some embodiments, the clamp connector comprises a connector body having a first end, a second end and an arc-shaped arm connecting the first and second ends, wherein the passageway passes through the first and second arms. However, it may be appreciated that the connector body many have a variety of suitable shapes and forms. Typically, the visualization instrument has a handle to which the connector body is attachable. The means for connecting may have a variety of forms including a fitting, such as a quick connector. In some embodiments, the quick connector comprises a side-action quick connector which allows the connector to be attached and detached from a side approach. Typically, the delivery catheter includes a handle at its distal end and the clamp connector includes a locking mechanism which is capable of locking the handle of the delivery catheter to the clamp connector. Such locking holds the delivery catheter in place in relation to the visualization instrument. In some embodiments, the locking mechanism tightens the passageway through the connector body to hold the at least a portion of the catheter by frictional forces. The locking mechanism may comprises a screw, knob or tensioning lever, among other mechanisms. While the delivery catheter is locked in place, the occlusal stent may be deployed from the delivery catheter by manipulation of the handle of the delivery catheter. 
     In preferred embodiments, the delivery catheter comprises positioning rod, a tubular shaft extending from its proximal end to its distal end, and a handle positioned at its proximal end. The positioning rod is disposed within the tubular shaft and is fixedly attached to the handle. A receptacle formable within the distal end of the delivery catheter is disposed within the tubular shaft distal of the distal end of the positioning rod. The distance between the distal end of the positioning rod and the distal end of the tubular shaft is the axial length of the receptacle. The tubular shaft is slidable in relation to the positioning rod so that sliding of the tubular shaft shortens the axial length of the receptacle exposing the occlusal stent. When the occlusal stent has a self-expanding design, exposure of the occlusal stent deploys the occlusal stent within the lung passageway. In some embodiments, the occlusal stent is self-expanding in free space to a configuration that has an approximately 11 mm outer diameter. Alternatively, the occlusal stent may be expanded by alternative mechanisms after it has been released into the lung passageway. In either case, the occlusal stent may be comprised of a wire structure or any other type of framework at least partially encapsulated in a polymer. The wire structure is used as an example in the following descriptions but it can be appreciated that the framework can be of a variety of types. 
     Typically, the positioning rod comprises a main body coil extending along the positioning rod terminating at a plunger tip. In some embodiments, the main body coil has an axial length in the range of approximately 80 to 100 cm and the main body coil is comprised of stainless steel wire. 
     In some embodiments, the visualization instrument comprises a bronchoscope. It may be appreciated that any suitable bronchoscope may be used, including conventional bronchoscopes. A principal advantage of the present invention is that it allows a user to modify a conventional bronchoscope for use in delivery of occlusal stents in a convenient and economical manner. However, it may also be appreciated that other instruments or catheters may be used which provide viewing or visualization capabilities. Thus, the visualization instrument may further comprise a sheath having a proximal end, a distal end, a lumen extending therethrough and the occlusive member disposed near its distal end, the lumen configured to receive the bronchoscope so that the occlusive member is disposed near the distal end of the bronchoscope. The sheath typically comprises a flexible tubular body having a length in the range from 40 cm to 70 cm, an inside lumen diameter in the range from 1.5 mm to 10 mm, and a wall thickness in the range from 0.2 mm to 0.7 mm. 
     In a second aspect of the present invention, a loading system is provided. In preferred embodiments, the loading system includes an occlusal stent, a loading body, and a loading mandrel. Again, the occlusal stent is transitionable between an expanded configuration and a contracted configuration. The loading body has a wide-mouthed end and a narrow-mouthed end, wherein the wide-mouthed end is configured to receive the occlusal stent in the expanded configuration and the narrow-mouthed end is configured to hold the occlusal stent in the contracted configuration. The loading mandrel has a proximal end, a distal end, and an attachment device disposed near its distal end that is removably attachable to the occlusal stent. The attachment device may be comprised of a hook, clasp, fastener or magnet, to name a few. The mandrel is configured to load the removably attached occlusal stent into the wide-mouthed end and move the occlusal stent to the narrow-mouthed end. 
     In preferred embodiments, the loading body comprises a loading receptacle within the wide-mouthed end, wherein the loading receptacle is sized to receive the occlusal stent in the expanded configuration. The loading receptacle may have any suitable size or shape. Typically, the loading receptacle is cylindrical in shape and has a diameter in the range of approximately 10 to 13 mm. In addition, loading body comprises a holding tube within the narrow-mouthed end, wherein the holding tube is sized to receive the occlusal stent in the contracted configuration. Similarly, the holding tube may have any suitable size or shape, typically having a cylindrical shape with a diameter in the range of approximately 2 to 2.5 mm. Further, in preferred embodiments, the loading body comprises a restrictor disposed between the loading receptacle and the holding tube, wherein the restrictor has a funnel shape to transition the occlusal stent from the expanded configuration to the contracted configuration. In some embodiments, loading mandrel includes a first marking near its distal end and the loading body includes a second marking near its narrow-mouthed end, wherein alignment of the first marking with the second marking positions the occlusal stent within the narrow-mouthed end. 
     In some embodiments, the loading system further comprises a delivery catheter having a proximal end, a distal end and a receptacle formable within its distal end for loading the occlusal stent therein. The narrow-mouthed end of the loading body is typically configured to mate with the distal end of the delivery catheter. The occlusal stent may then be moved from the narrow-mouthed end to the receptacle within the distal end of the delivery catheter with the use of the loading mandrel. Further, in some embodiments the catheter is provided pre-positioned to the narrow-mouthed end of the loading body and the occlusal stent is provided pre-positioned and or pre-attached to the wide-mouthed end and or pre-connected to the positioning rod of the catheter. 
     In a third aspect of the present invention, methods of delivering an occlusal stent to a lung passageway within a lung of a patient are provided. In preferred embodiments, such methods include providing a visualization instrument, wherein the instrument has a proximal end, distal end, a working lumen therethrough, means for visualization near the distal end, and an occlusive member disposed near its distal end which is configured to be expandable to occlude the lung passageway. The visualization device is advanced through a trachea of the patient to a first location with the lung passageway. The lung passageway is then occluded at the first location with the occlusive member and the lung passageway evacuated. The method further includes providing a delivery catheter having a proximal end, a distal end, and an occlusal stent loaded within a receptacle within its distal end. The delivery catheter is advanced through the working lumen of the visualization instrument so that the distal end of the delivery catheter extends beyond the distal end of the visualization instrument to a second location within the lung passageway. The distal end of the delivery catheter is then retracted which releases the occlusal stent from the receptacle at the second location within the evacuated lung passageway. 
     Such methods may be performed within lung passageways of various dimensions, shapes and branching patterns. For example, lung passageway may be comprised of a main passageway and at least one branch passageway. The first location may be disposed within the main passageway and the second location disposed within one of the at least one branch passageways. Thus, the distal end of the delivery catheter may be steered or guided in various directions as it is advanced beyond the visualization instrument to reach a desired branch passageway. 
     Typically, the methods further comprise withdrawing the delivery catheter from the visualization instrument after releasing the occlusal stent while the lung passageway remains evacuated. Another delivery catheter having a proximal end, a distal end, and another occlusal stent loaded within a receptacle within its distal end may then be provided. This may be the delivery catheter that was removed with a new occlusal stent loaded therein, or a different delivery catheter that has been preloaded with an occlusal stent. The another delivery catheter is then advanced through the working lumen of the visualization instrument so that the distal end of the another delivery catheter extends beyond the distal end of the visualization instrument to a third location within the evacuated lung passageway. The third location may be disposed within another of the at least one branch passageways. 
     Again, the delivery catheter typically comprises a tubular shaft extending from its proximal end to its distal end wherein the occlusal stent is disposed within the tubular shaft within the distal end of the catheter. Thus, releasing comprises withdrawing the tubular shaft to expose the occlusal stent. In preferred embodiments, the delivery catheter comprises a handle disposed at its proximal end and the tubular shaft is slidably connected with the handle by a handle button or any other hand-operated feature such as a loop or trigger, henceforth referred to as button. In these embodiments, withdrawing comprises moving the handle button to withdraw the tubular shaft. 
     In some embodiments, the visualization instrument has a handle section near its proximal end, and the method further comprises connecting a clamp connector to the handle section of the visualization instrument. Typically, the clamp connector has a passageway therethrough so that advancing the delivery catheter comprises passing the distal end of the delivery catheter through the passageway of the clamp connector and into the working lumen of the visualization instrument. The working lumen is typically accessible via an access port, which extends through the proximal end and typically the handle section of the visualization instrument. The clamp connector can attach directly to the working lumen access port or elsewhere on the visualization instrument handle section as described in the following detailed descriptions. Again, the delivery catheter typically comprises a tubular shaft extending from its proximal end to its distal end and a handle disposed at its proximal end. The clamp connector may further include a locking mechanism wherein the method would further comprise actuating the locking mechanism to lock the handle of the delivery catheter to the clamp connector. The handle of the delivery catheter can be provided in a variety of configurations, such as a configuration that does not enter the working channel of the bronchoscope as well as a configuration that can enter the working channel of the bronchoscope, and combinations thereof. The clamp connector can also be provided in many configurations, wherein the clamp connector physically attaches to a portion of the bronchoscope, typically in the handle section and sometimes directly to the access port, and allows access of the catheter to the bronchoscope working channel. The clamp connector can be an item provided separately, or can be provided as an integral piece of the delivery catheter, and can be reusable or disposable. 
     When the tubular shaft is slidably connected with the handle of the catheter by a handle button, releasing may comprise moving the handle button to withdraw the tubular shaft and expose the occlusal stent. Releasing may also comprise expanding the occlusal stent to occlude the lung passageway. 
     In a fourth aspect of the present invention, methods are provided for using the loading system. Such methods include providing a loading mandrel having a proximal end, a distal end and an occlusal stent removably attached to its distal end, wherein the occlusal stent is transitionable between an expanded configuration and a contracted configuration. These methods also include providing a loading body having a wide-mouthed end and a narrow-mouthed end, wherein the wide-mouthed end is configured to receive the occlusal stent in the expanded configuration and the narrow-mouthed end is configured to hold the occlusal stent in the contracted configuration. The loading mandrel is positioned within the loading body so that the occlusal stent is near the wide-mouthed end. The loading mandrel is then manipulated to load the occlusal stent into the wide-mouthed end and move the occlusal stent to the narrow-mouthed end within the loading body. 
     When the loading body comprises a loading receptacle within the wide-mouthed end, manipulating the loading mandrel may comprise moving the loading mandrel relative to the loading body so that the occlusal stent is positioned within the loading receptacle. When the loading body includes a restrictor adjacent to the loading receptacle, manipulating the loading mandrel may comprise moving the loading mandrel relative to the loading body so that the occlusal stent enters the restrictor. And when the loading body includes a holding tube adjacent to the restrictor, manipulating the loading mandrel may comprise moving the loading mandrel relative to the loading body so that the occlusal stent is positioned within the holding tube. In some embodiments, the loading mandrel includes a first marking near its distal end and the loading body includes a second marking near its narrow-mouthed end. In these embodiments, the method may further comprise aligning the first marking with the second marking indicating that the occlusal stent is positioned within the narrow-mouthed end. The methods may further comprise detaching the occlusal stent from the loading mandrel. 
     A delivery catheter having a proximal end, a distal end and a receptacle formable within its distal end for loading the occlusal stent therein may also be provided. Such methods may then further include transferring the occlusal stent from the narrow-mouthed end of the loading body to the receptacle of the delivery catheter. To accomplish this, the method may further comprise mating the distal end of the delivery catheter with the narrow-mouthed end of the loading body prior to the transferring step. Transferring may also comprise advancing a loading mandrel through the open-mouthed end of the loading body which pushes the occlusal stent into the distal end of the delivery catheter. The delivery catheter loading system and occlusal stent can be provided separately in which case the user may mate the elements for transferring, or the pieces can be provided pre-positioned together or in a mated configuration so that the user only has to transfer the stent into the catheter through the pre-positioned loading system. 
     It may be appreciated that the delivery system and/or loading system may be used for a variety of applications. For example, components of the delivery system may be used to deliver non-occlusal tracheobronchial stents, bronchopulmonary fistula plugs or stents, or occlusal stents for the treatment of tuberculosis. Further, components of the delivery system may be modified for to deliver vascular stents, vascular grafts or vascular occlusal devices to the vascular system to treat a variety of vascular ailments. Likewise, the loading system may be used to load a variety of stent-like devices within instruments and catheters having a receptacle for receiving the devices. Further, the clamp connector of the present invention may be used for the passage of any suitable instrument therethrough, such as instruments for implant removal, endoluminal injection (such as of a therapeutic agent, a hemostatic agent, etc.), specimen collection (such as for a biopsy), inspection, or other treatment, such a radiation therapy, etc. 
     Other objects and advantages of the present invention will become apparent from the detailed description to follow, together with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an embodiment of a delivery system of the present invention. 
         FIG. 2  provides a cross-sectional side view of an embodiment of an occlusal stent delivery catheter. 
         FIG. 3  provides a cross-sectional side view of a tubular shaft of the delivery catheter of  FIG. 2 . 
         FIG. 4  provides a cross-sectional side view of the positioning rod of  FIG. 2 . 
         FIGS. 5 ,  6 - 6 A,  7  illustrates various views of an embodiment of a clamp connector. 
         FIGS. 8A-8B  illustrate an embodiment of a clamp connector having the form of a bracket. 
         FIGS. 8C-8E  illustrate an embodiment of a clamp connector having the form of an elongate holder. 
         FIGS. 9-9A  illustrate an embodiment of an occlusal stent. 
         FIG. 10A  illustrates an exploded view of an embodiment of a loading system of the present invention. 
         FIG. 10B  provides a top view of a loading body having a mandrel positioned therein. 
         FIGS. 11A-11D  illustrate loading of an occlusal stent into the loading system. 
         FIG. 11E-11G  illustrate transferring of an occlusal stent to a delivery catheter. 
         FIGS. 12A-12C  illustrate an alternative method of loading a delivery catheter with an occlusal stent. 
         FIGS. 13A-13C  illustrate an similar method of loading a delivery catheter to that of  FIGS. 12A-12C . 
         FIGS. 14A-14C  illustrates methods of using the occlusal stent delivery system of the present invention within lung passageways. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Lung volume reduction is performed by collapsing a target lung tissue segment, usually within lobar or sub-lobular regions of the lung which receive air through a single lung passage, i.e., segment of the branching bronchus which deliver to and receive air from the alveolar regions of the lung. Such lung tissue segments are first isolated and then collapsed by aspiration of the air (or other gases or liquids which may be present) from the target lung tissue segment. Lung tissue has a very high percentage of void volume, so removal of internal gases can reduce the lung tissue to a small percentage of the volume which it has when fully inflated, i.e. inflated at normal inspiratory pressures. 
     The methods of the present invention rely on accessing the target lung tissue segment using an occlusal stent delivery system  10  adapted to be introduced endotracheally into the bronchus of the lung. An exemplary delivery system  10  is illustrated in  FIG. 1 . As shown, the system  10  comprises a bronchoscope  12  having a proximal end  14 , a distal end  16  and at least a working lumen  18  and a scope lumen  20  extending from the proximal end  14  to the distal end  16 . Additional lumens, such as an aspiration lumen  22 , may also extend therethrough. The bronchoscope  12  also includes a handle  24  disposed near the proximal end  14 . The handle  24  is formed to include a sidearm  24   a  which provides access to the working lumen  18 . The handle  24  also includes a connector  28  which permits attachment to an external viewing scope. 
     It may be appreciated that the bronchoscope  12  included in this embodiment of the system  10  of the present invention may be comprised of any suitable bronchoscope, including conventional bronchoscopes. Conventional bronchoscopes are available from a number of commercial suppliers. Particular bronchoscopes which may be used in the methods and assemblies of the present invention are commercially available from Olympus and Pentax. A principal advantage of the present invention is that it allows a user to modify a conventional bronchoscope for use in delivery of occlusal stents in a convenient and economical manner. However, it may also be appreciated that other instruments or catheters may be used which provide viewing or visualization capabilities. 
     In this embodiment, the system  10  also includes a sheath  30  having an occlusive member  32  disposed near its distal end, a full description of which is provided in U.S. Pat. No. 6,585,639, assigned to the assignee of the present invention and incorporated by reference for all purposes. The sheath  30  includes a flexible tubular body having a distal end and an occlusive member  32  disposed at or near the distal end of the tubular body. Typically, the occlusive member will be formed from an inflatable elastomeric material which, when uninflated, lies closely over an exterior surface of the distal end of the flexible tubular body. Upon inflation, the material of the occlusive member will simply stretch and permit radial expansion. The elastic nature of the member will permit the member to conform to irregular geometries of a target lung passageway to provide for effective sealing. 
     The system  10  of  FIG. 1  also includes an occlusal stent delivery catheter  40  which is positionable within the working lumen  18  of the bronchoscope  12 . The catheter  40  comprises a tubular shaft  41  having a distal end  42 , wherein the distal end  42  is extendable beyond the distal end  16  of the scope  12 . This may be achieved by slidably advancing the catheter  40  within the working lumen  18 . The catheter  40  also includes a positioning rod  44  that is disposed within the tubular shaft  41 . The positioning rod  44  is used to expel an occlusal stent  46  from the distal end  42  of the catheter  40 , as will be described and illustrated in later sections. The catheter  40  is positionable within the working lumen  18  of the scope  12  by advancement through the sidearm  24   a  of the handle  24 . 
     The catheter  40  also includes a handle  48  which typically remains outside of the sidearm  24   a , though inn some optional configurations an extension of the handle  48  can enter the  24   a  sidearm or the working lumen  18  of the bronchoscope. Both the tubular shaft  41  and the positioning rod  44  are attached to the handle  48  so that gross movement of the handle  48  toward or away from the sidearm  24   a  advances or retracts the catheter  40  within the working lumen  18 . To assist in positioning the catheter  40  within the working lumen  18  and to lock portions of the catheter  40  in relation to the scope  12 , a clamp connector  60  may be used. The clamp connector  60  may be joined with the sidearm  24   a  by a quick connector  62 , however any connecting mechanism may be used. The catheter  40  is advanceable through the clamp connector  60  and the handle  48  is lockable to the clamp connector  60  by a locking mechanism  64 . As shown in later figures, the clamp connector can assume other shapes and configurations and can attach to other portions of the bronchoscope in the bronchoscope handle area with a variety of connection mechanisms. 
     As will be described in later sections, the positioning rod  44  is fixedly attached to the handle  48  and the tubular shaft  41  is slidably attached to the handle  48 . Thus, locking of the handle  48  to the clamp connector  60  using locking mechanism  64  in turn locks the positioning rod  44  in relation to the scope  12 . The tubular shaft  41  may then be slidably advanced or retracted in relation to the scope  12  and the positioning rod  44  by movement of a handle button  50  on the handle  48 . The handle button  50  is fixedly attached to the tubular shaft  41 . In this manner, the tubular shaft  41  may be retracted to deploy the occlusal stent  46 . It may be appreciated that such a handle button  50  is an example mechanism for achieving such movement of the tubular shaft  41  and that other suitable mechanisms may be used. 
     Occlusal Stent Delivery Catheter 
       FIG. 2  provides a cross-sectional side view of an embodiment of an occlusal stent delivery catheter  40 . As shown, the catheter  40  includes a positioning rod  44  having a distal end  45 , a tubular shaft  41  and a handle  48 . The positioning rod  44  is disposed within the tubular shaft  41  and is fixedly attached to the handle  48 , in this embodiment by a set screw  72  however any mechanism can be used. The tubular shaft  41  is fixedly attached to a catheter adapter  70  which is sized to fit at least partially within the handle  48 . The adapter  70  is slidably attached to the handle  48  with the use of a handle button  50 . The handle button  50  is attached to the catheter adapter  70  and shaped to extend through a slot (not shown) in the handle  48  so that the button  50  is able to slide along the slot thereby moving the tubular shaft  41  in relation to the handle  48 . 
     The handle button  50  is positionable so that a receptacle  80  is formed within the tubular shaft  41  between the distal end  45  of the positioning rod  44  and the distal end  42  of the tubular shaft  41 . The receptacle  80  is sized to hold an occlusal stent  46  in a contracted form. In preferred embodiments, the maximum axial length of the receptacle  80  is in the range of approximately 20 to 30 mm. Movement of the button  50  along the slot retracts the tubular shaft  41 , shortening the axial length of the receptacle  80  until the distal end  45  of the positioning rod  44  meets the distal end  42  of the tubular shaft  41 . At this point the receptacle  80  is completely diminished and the occlusal stent  46  is fully exposed and released. 
       FIG. 3  provides a cross-sectional side view of the tubular shaft  41  of  FIG. 2 . As shown, the tubular shaft  41  is connected with a catheter adapter  70 . In this embodiment, the connection is achieved with adhesive and heat shrink tubing  74 , however any connection methods and materials may be used. In addition, the tubular shaft  41  has a end portion  52  that terminates at the distal end  42  of the shaft  41 . In preferred embodiments, the end portion has an axial length in the range of approximately 20 to 120 mm. The end portion  52  is typically comprised of a more flexible material than the remainder of the tubular shaft  41 . Such differences in flexibility provide sufficient rigidity throughout the shaft  41  while maintaining maneuverability and kink resistance near the distal end  42 . In addition, the end portion  52  typically has a slightly larger diameter than the remainder of the shaft  41  to accommodate the cross-sectional diameter of the collapsed stent  46  while minimizing the diameter of the remainder of the shaft  41  which minimizes friction within the visualization instrument. In preferred embodiments, the overall length of the tubular shaft  41  and adapter  70  is in the range of approximately 30 to 34 inches. 
     The tubular shaft  41  may include markings  82 , as shown. The markings  82  may be comprised of ink or any suitable marking material. Any number of markings  82  may be present, such as a stripe approximately 20 mm from the distal end  41  and another approximately stripe 22.5 mm from the distal end  41 . Such markings  82  may be used to assist in positioning the distal end  41  in a passageway. The markings  82  may be observed through the scope  12  as the distal end  41  is manipulated within a lung passageway. Particular markings may be aligned with particular anatomical features to assist in proper placement of the stent  46 . For example, when a stent  46  is to be positioned within a relatively large lung passageway, a particular marking such as a distal-most marking may be aligned with the ostium associated with the target lung passageway. Whereas, when a stent  46  is to be positioned within a smaller lung passageway, a different marking, such as a proximal-most marking may be aligned with the ostium associated with the target lung passageway. 
       FIG. 4  provides a cross-sectional side view of the positioning rod  44  of  FIG. 2 . In this embodiment, the positioning rod  44  is comprised of a main body coil  92  which extends along the length of the rod  44  terminating at a plunger tip  94 . Thus, the axial length of the main body coil  92  is in the range of 34 to 40 inches. Typically, the main body coil  92  has an inner diameter in the range of 0.030 to 0.040 inches. The main body coil  92  is comprised of 304 stainless steel wire, however any suitable material may be used. In this embodiment, the plunger tip  94  is comprised of 303 stainless steel and has a maximum outer diameter in the range of 0.075 to 0.085 inches. The positioning rod  44  also includes a push end hypotube  90  disposed within the main body coil  92  opposite to the plunger tip  94 . In this embodiment, the hypotube  90  is comprised of 304 stainless steel, however any suitable material may be used. The hypotube  90  has an inner diameter of approximately 0.023 inches and an outer diameter of approximately 0.0355 inches. In addition, the hypotube  90  has an axial length of in the range of 14 to 18 inches. Adjacent to the hyptotube  90 , within the main body coil  92 , is a strain relief coil  96 . In this embodiment, the strain relief coil  96  has an axial length in the range of 1 to 2 inches. The strain relief coil  96  is comprised of 304 stainless steel wire, however any suitable material may be used. 
     Clamp Connector 
       FIG. 5  provides a perspective view of an embodiment of a clamp connector  60 . The clamp connector  60  comprises a connector body  100 , a quick connector  62 , and a locking mechanism  64 . The connector body  100  may be comprised of any suitable material, such as a rigid thermoplastic, acetyl butyl styrene (ABS), Delrin.RTM. acetal resin, nylon, polycarbonate, metal, or various polymers, to name a few. The connector body  100  may also have any suitable form. In preferred embodiments, the body  100  has a C-shaped form, as shown, having a first end  102 , a second end  104  and an arc-shaped arm  106  therebetween. The body  100  has a passageway  108  that extends through the first and second ends  102 ,  104 . Therefore, an instrument, such as the delivery catheter  40  may be passed through the passageway  108  so that the handle  48  of the catheter  40  is positioned at least partially within at least the second end  104 , typically so that the handle button  50  remains outside of the connector body  100 . By positioning the handle  48  at least partially within the second end  104 , the handle  48  can be locked in relation to the connector  60  with the use of the locking mechanism  64 . In some embodiments, the passageway  108  extending through the second end  104  has a split  110 . Such a split  110  may be seen in  FIG. 5  and  FIG. 7 . The split  110  allows the passageway  108  through the second end  104  to expand. At least a portion of the handle  48  may then be advanced into the expanded passageway  108 . A locking mechanism  64 , such as a screw, knob or quick release tensioning lever, may then be tightened, turned or actuated to close the split  110 . This in turn applies compressive forces to the handle  48  so that it is held by friction. It may be appreciated, however, that any suitable locking mechanism may be used. The button  50  may then be manipulated to move the tubular shaft  41  of the delivery catheter  40  while the handle  48  is locked to the connector  60 . 
       FIG. 6  provides a top perspective view of an embodiment of a clamp connector  60 . Again the clamp connector  60  is shown to have a first end  102 , a second end  104  and an arc-shaped arm  106  therebetween. A quick connector  62  is shown joined with the first end  102 , and a locking mechanism  64  is shown joined with the second end  104 .  FIG. 6A  illustrates a cross-sectional view along line A-A of  FIG. 6 . This view illustrates the passageway  108  extending through the quick connector  62 , the first end  102 , and the second end  104 . In addition, this view illustrates the locking mechanism  64 .  FIG. 7  provides another perspective view of the clamp connector  60  of  FIG. 5 . 
     The clamp connector  60  provides a number of advantages. As mentioned, the clamp connector  60  provides a stable platform for introduction of the stent delivery catheter  40  and various other instruments into the working lumen  18  of the bronchoscope  12 . As described in this embodiment, the clamp connector fixes the position of the catheter or instrument to the bronchoscope, or optionally fixes a component of the catheter or instrument to the bronchoscope while another component of the catheter or instrument is free to advance or retract within the bronchoscope working lumen while the fixed catheter component remains stationary. In addition, the connector  60  provides for locking of these instruments in a fixed position relative to the bronchoscope. Further, various embodiments of the connector  60  include a quick connector  62  which allows the connector  60  to be quickly and easily attached and detached from the bronchoscope  12 . Some embodiments include a side-action quick connector  62  which allows the connector to be attached and detached from a side approach rather than an axial approach. In addition to being more ergonomic, this approach reduces any axial pushing or pulling on the bronchoscope  12  which could inadvertently move the bronchoscope from its desired position. Some embodiments of the connector  60  also include a seal or are attachable with a seal. Commercially available seals include Biopsy Valve (MAJ-210) provided by Olympus America, Inc. (Melville, N.Y.). Such seals may be mounted on the connector  60  for mating with the bronchoscope  12  rather than mounted directly on the bronchoscope  12 . 
     Although the clamp connector  60  may have various forms, the C-shaped form provides particular advantages. The C-shape provides direct access to the passageway  108  through the first end  102  while it is connected to the bronchoscope  12 . When the stent delivery catheter or other instrument is passed through the passageway  108 , the physician or user can easily grasp the catheter near the first end  102  to assist in advancing the catheter through the bronchoscope  12 . This may reduce any risk of kinking the catheter and may assist is passing the catheter through seals within the bronchoscope and/or clamp connector. In addition, such direct access to the passageway  108  through the first end  102  allows the insertion of various instruments without passing the instruments through the second end  104 . For example, a syringe may be inserted through the first end  102  to directly inject drugs, etc., into the working lumen  18  of the bronchoscope  12 . Likewise suction can be drawn through the working lumen  18  and the first end  102  without drawing suction through the entire connector  60 . 
       FIGS. 8A-8B  illustrate another embodiment of a clamp connector  60 . In this embodiment, the clamp connector  60  has the form of a bracket which attaches to the handle  24  of a bronchoscope  12 , as shown in  FIG. 8A . An occlusal stent delivery catheter  40  may be advanced through the side arm  24   a  of the bronchoscope handle  24  so that its distal end  42  passes through the bronchoscope  12 . The positioning rod  44 , which passes through the catheter  40  and extends from the its proximal end, may then be coupled with the clamp connector  60  to lock the positioning rod  44  in a fixed position in relation to the bronchoscope  12 .  FIG. 8B  illustrates the occlusal stent delivery catheter  40  of this embodiment showing the positioning rod  44  extending through the tubular shaft  41 . The occlusal stent  46  is shown disposed within the tubular shaft  41  near the distal end  42 . Thus, when the positioning rod  44  is locked to the connector  60 , the rod  44  is fixed in place. The tubular shaft  41  may then be retracted to expose and deploy the stent  46 . By fixing the positioning rod  44  in relation to the bronchoscope  12 , there is reduced variability in positioning the stent  46  thereby improving placement accuracy. 
       FIGS. 8C-8E  illustrate another embodiment of a clamp connector  60 . In this embodiment, the clamp connector  60  includes an elongate holder  170 , a base  172  and a support  174 , as illustrated in  FIG. 8C . The elongate holder  170  is comprised of a shaft  176  having a plate  178  (with an aperture  180 ) attached near one end, and its other end is configured to receive the support  174 . Referring to  FIG. 8D , the elongate holder  170  is coupleable with a bronchoscope  12 . The plate  178  may be positioned against the bronchoscope  12  so that the side arm  24   a  of the bronchoscope  12  passes through the aperture  180 . The base  172  is positioned against the bronchoscope  12  on a side opposite to the side arm  24   a  so that the base  172  wraps around the bronchoscope  12  as shown. The plate  178  may then be attached to the base  172  with the use of screws  182  or any suitable device. This fixes the clamp connector  60  to the bronchoscope  12 . The embodiments described in  FIGS. 8A-8D  are exemplary and any bracket configuration which attaches to the bronchoscope can be used. 
     An occlusal stent delivery catheter  40  may then be advanced through the side arm  24   a  and coupled with the clamp connector  60  to lock the positioning rod  44  in a fixed position in relation to the bronchoscope  12 .  FIG. 8E  provides a side view of the occlusal stent delivery catheter  40  positioned on the clamp connector  60 . The plate  178  may be connected with the shaft  176  at any suitable angle so that the shaft  176  holds the catheter  40  in a desired position while allowing manipulation of the bronchoscope  12 . The positioning rod  44  passing within the catheter  40  is locked in place by coupling the rod  44  with the support  174 . Thus, the rod  44 , clamp connector  60  and bronchoscope  12  are in fixed relation to each other. The tubular shaft  41  of the delivery catheter  40  may then be retracted to expose and deploy the stent  46 . Again, by fixing the positioning rod  44  in relation to the bronchoscope  12 , there is reduced variability in positioning the stent  46  thereby improving placement accuracy. 
     Occlusal Stent 
     The occlusal stent delivery system  10  may be used to deliver a variety of occlusal stents  46 . Occlusal stents  46  may also be referred to, for example, as occlusal devices, occlusive stents, obstructive devices or plugs. Exemplary occlusal stents  46  are provided in U.S. Pat. No. 6,527,761,  and U.S. Provisional Patent Application No. 60/628,649,  both assigned to the assignee of the present invention and incorporated by reference for all purposes. A number of embodiments of occlusal stents  46  are comprised of structural supports which expand to anchor the occlusal stent  46  in a lung passageway. 
     Referring now to  FIG. 9  and  FIG. 9A , an embodiment of an occlusal stent  46  is shown. Here, the occlusal stent  46  comprises a braid  400 . The braid  400  may be comprised of any type of wire, particularly superelastic and/or shape-memory wire, polymer or suitable material. In this embodiment, the braid  400  is comprised of 0.006″ Nitinol wire (30-45% CW, oxide/etched surface). The wire braid  400  can be woven from wires having the same diameter, e.g. 24 wires each having a 0.006″ diameter, or wires having varied diameters, e.g. 12 wires each having a 0.008″ diameter and 12 wires each having a 0.003″ diameter. Other numbers of wires and combinations of wire diameters can also be used. 
     The braid  400  is fabricated on a mandrel having a diameter close in size to the desired diameter of the occlusal stent  46  when unrestrained or in free space. The unrestrained diameter of the stent  46  is typically desired to slightly exceed the internal diameter of the bronchial tube within which it will be placed. Thus, the diameter of the braid  400  may vary depending on the intended usage of the stent  46 . Once the braid has been fabricated, the braid is then cut to an appropriate length and shape-set to a desired configuration by heat treatment. The desired configuration generally comprises the ends of the cut length of braid collapsed to form ends or tails, which will be secured and covered by bushings  401 , and a portion therebetween having an overall shape conducive to occluding a lung passageway. When other materials, such as Elgiloy.RTM. and stainless steel, are used, the wire is formed into the desired configuration using methods different from shape setting methods used for shape memory alloys. After shape-setting, the braid may then be etched to remove oxidation and to form a new passivation layer. 
     The desired configuration may include a variety of overall shapes, each allowing the occlusal device  46  to perform differently or occlude lung passageways of differing shapes, sizes and configurations.  FIG. 9  is a side view of one embodiment of the stent  46  having shoulders  402  which are at an angle which is approximately 90 degrees to a longitudinal axis  404  of the stent  46 . Shoulders  402  at such an angle allow maximum contact surface area in relation to length of the stent  46 . This is useful when placing the stent  46  into short bronchial segments or take-offs.  FIG. 9A  is an end view of the embodiment shown in  FIG. 9 . 
     Typically, the braid  400  is connected to, encapsulated in, coated or impregnated with a material to prevent flow of gases or liquids through the occlusal device  46 , thereby providing an obstruction. In addition, the material may optionally include an antibiotic agent for release into the lung passageway. Examples of obstructive materials include a thin polymer film  120  at least partially encapsulating the occlusal device  46 , which may be used to seal against the surface of the lung passageway. Such a design is depicted in  FIG. 9 . As shown, the film  120  does not completely encapsulate the device  46 , leaving a portion of the shoulders  402  exposed. This allows for air to escape from the device  46  when the device is collapsed or contracted. In some embodiments, a bushing  401  located near the exposed area is color coded to signify the area so that the device  46  is loaded in the desired orientation within the delivery catheter  40 . 
     Occlusal Stent Loading 
     One or more occlusal stents  46  may be loaded within the delivery system  10  for delivery within a lung passageway. In preferred embodiments, the occlusal stent(s) are loaded into the delivery system  10  with the use of an occlusal stent loading system  130 . An embodiment of a loading system  130  of the present invention is illustrated in  FIG. 10A . As shown, the system  130  includes a loading body  134 , a loading mandrel  136 , and a lubricious liner  132 . The loading body  134  has a wide-mouthed end  138  and narrow-mouthed end  140 , wherein the occlusal stent  46  is loadable into the wide-mouthed end  138  in an expanded configuration and removed from the narrow-mouthed end  140  in a contracted configuration. Thus, the loading body  134  contracts the occlusal stent  46  for loading into the delivery catheter  40 . The loading body  134  is also used to load the contracted stent  46  into the delivery catheter  40 . 
     The occlusal stent  46  can be loaded into the loading body  134  with the use of the loading mandrel  136 . The mandrel  136  includes a proximal end  141 , a distal end  142  and a shaft  143  therebetween. An attachment device  144  is disposed near the distal end  142  which is used to removably attach to the occlusal stent  46 . The attachment device  144  may be integral with the mandrel  136  or mounted on, attached to, coupled with the mandrel  136 , for example. The attachment device  144  may have any suitable form, including a hook, fork, clasp, fastener, or magnet, to name a few. The mandrel  136  may also include a mandrel grip  146  which has an inner lumen  148  sized for passage of the mandrel  136  therethrough so that the grip  146  may be positioned at any location along the length of the shaft  142 . In some embodiments, the grip  146  also serves as a depth stop when loading the stent  46  within the loading body  134 . In these embodiments, the grip  146  is preferably positioned in the range of approximately 34 to 38 mm from the proximal end  141  of the shaft  143 . The use of the grip  146  as a depth stop will be further described in later sections. In addition, the mandrel  136  may also include one or more mandrel end covers  149 . 
     The shaft  143  is sized to be passed through loading body  134 .  FIG. 10B  provides a top view of the loading body  134  having the mandrel  136  positioned therein. As shown, the body  134  includes a loading receptacle  150 , a restrictor  152  and a holding tube  154 . The lubricious liner  132  is shown inserted into the wide-mouthed end  138  and positioned so that the liner  132  extends through the restrictor  152  and holding tube  154 .  FIGS. 11A-11D  illustrate how an occlusal stent  46  may be prepared for loading into the catheter  40  with the use of these elements of the loading body  134 . 
       FIG. 11A  illustrates a portion of the loading body  134  wherein the distal end  142  of the loading mandrel  136  is shown passed through the narrow-mouthed end  140  to and beyond the wide-mouthed end  138 . The attachment device  144  is shown attached to the occlusal stent  46 . In this embodiment, the attachment device  144  comprises a fork which releasably joins with the occlusal stent  46 . The mandrel  136  is then retracted, drawing the occlusal stent  46  into the loading receptacle  150  at the wide-mouthed end  138 , as shown in  FIG. 11B . Further retraction of the mandrel  136  pulls the occlusal stent  46  into the restrictor  152  which gradually collapses the stent  46 , as shown in  FIG. 11C . As the stent  46  collapses, air within the stent  46  is forced out toward the narrow-mouthed end  140 . Still further retraction of the mandrel  136  pulls the contracted stent  46  into the holding tube  154 , as shown in  FIG. 11D . The liner  132  serves to reduce any friction between the stent  46  and the loading body  134  as the stent  46  is collapsed and passed through the loading body  134 . Thus, the liner  132  may be comprised of any suitable material which reduces friction, such as Teflon.RTM. It may be appreciated that the liner  132  may alternatively be integral with the loading body  134  or may have the form of a coating on surfaces of the loading body  134 . The occlusal stent  46  is now ready for loading into the delivery catheter  40 . 
     It may be appreciated that the loading system  130  may be constructed from any suitable materials. Preferably, the loading body  134  is constructed from a material which allows visibility of the stent  46  throughout the loading process. This may ensure that the stent  46  is properly loaded within the loading body  134 . Alternatively or in addition, a variety of markings  82 ,  82 ′ may be used to ensure proper loading. For example, as shown in  FIG. 10A , the mandrel  136  may include a marking  82 , such as a line of ink, on the shaft  143  a desired distance from the distal end  142 . In preferred embodiments, the marking  82  is disposed approximately 0.3 inches from the distal end  142 . The loading body  134  then includes a corresponding marking  82 ′ near the narrow-mouthed end  140 , approximately 0.35 inches from the holding tube  154 . When the mandrel  136  is retracted so that the marking  82  on the shaft  143  is aligned with the marking  82 ′ on the loading body  134 , the occlusal stent  46  is properly positioned within the holding tube  154 . 
     The occlusal stent  46  may then be transferred to the delivery catheter  40 , as illustrated in  FIGS. 11E-11G .  FIG. 11E  illustrates the delivery catheter  40  positioned against the holding tube  154  of the loading body  134 . The loading mandrel  136  or any other suitable instrument is used to transfer the occlusal stent  46  to the distal end  42  of the delivery catheter  40 . As shown, the proximal end  141  of the loading mandrel  136  is advanced through the loading receptacle  150  and the restrictor  152  until it contacts the occlusal stent  46 . Continued advancement of the loading mandrel  136  pushes the occlusal stent  46  from the holding tube  154  and into the catheter  40 .  FIG. 11F  illustrates the loading mandrel  136  fully advanced so that the occlusal stent  46  is fully loaded within the catheter  40 . In some embodiments, the mandrel grip  146  assists in proper placement of the stent  46  within the holding tube  154  by serving as a depth stop for the loading mandrel  136 . The grip  146  is sized so that it may be advanced into the loading receptacle  150  but cannot be advanced into the restrictor  152 , thus serving as a depth stop. The grip is positioned along the length of the mandrel  136  so that when the grip  146  is positioned against the restrictor  152 , as shown in  FIG. 11F , the stent  46  is properly positioned within the holding tube  154 .  FIG. 11G  illustrates the distal end  42  of the catheter  40  removed from the loading body  134  and having the occlusal stent  46  loaded inside. 
     It may be appreciated that the loading system  130  may be adapted to load more than one occlusal stent  46 . For example, the holding tube  154  may be lengthened to hold two, three, four, five or more stents  46  at one time. The stents  46  may be individually loaded into separate delivery catheters, simultaneously loaded into a single delivery catheter or loaded in groups into a few catheters. 
       FIGS. 12A-12C  illustrate an alternative method of loading a delivery catheter  40  with an occlusal stent  46 . In this embodiment, one or more stents are loaded directly into the distal end  42  of the delivery catheter  40 . As shown in  FIG. 12A , the delivery catheter  40  includes a positioning rod  44  having a grasping device  160  disposed at its tip. In this example, the grasping device  160  has the shape of a ring, loop, hoop or circle. The device  160  may be comprised of any suitable material, such as wire, polymer, thread, fiber, or suture, to name a few. A restricting insert  162  is positioned at least partially within the distal end  42 , such as shown. Optionally it can be appreciated that the restricting insert  162  can be of the type that engages with an outer surface or edge of the distal end  42  so that the insert  162  is not at least partially within the distal end  42 . The restricting insert  162  is used to assist in collapsing and loading the stent  46  within the distal end  42  of the catheter  40 . This is achieved by retracting the tubular shaft  41  so that the grasping device  160  can be removably attached to a bushing  401  on an occlusal stent  46 . As shown in  FIG. 12A , at least one of the bushings  401  includes a notch  164  which is mateable with the grasping device  160 . As shown in  FIG. 12B , the grasping device  160  attaches to the bushing  401  and draws the occlusal stent  46  through the restricting insert  162  and into the tubular shaft  41  of the catheter  40 .  FIG. 12C  shows the distal end  42  of the catheter  40  having the occlusal stent  46  loaded inside and the restricting insert  162  removed. 
       FIGS. 13A-13C  illustrate an similar method of loading a delivery catheter  40  with an occlusal stent  46 . As shown in  FIG. 13A , the delivery catheter  40  includes a positioning rod  44  having a grasping device  160  disposed at its tip. In this example, the grasping device  160  has the shape of a pincher or claw. The tubular shaft  41  is retracted so that the grasping device  160  pinch onto a bushing  401  on an occlusal stent  46 . As shown in  FIG. 13A , at least one of the bushings  401  includes one or more protrusions  166  which the grasping device  160  is able to utilize in grasping. As shown in  FIG. 13B , the grasping device  160  grasps the bushing  401  and draws the occlusal stent  46  through the restricting insert  162  and into the tubular shaft  41  of the catheter  40 . A restricting insert  162  is positioned at least partially within the distal end  42 , as shown. The restricting insert  162  is used to assist in collapsing the stent  46  and loading the stent  46  within the distal end  42  of the catheter  40 . The grasping device  160  may also be used to retrieve or adjust an occlusal stent  46  which has been deployed in a lung passageway LP, as illustrated in  FIG. 13C . As shown, the distal end  42  of the catheter  40  may be retracted to expose the grasping device  160  which can be used to grasp onto the bushing  401  of the occlusal stent  46 . The stent  46  may then be manipulated by the grasping device  160 . In some methods, the occlusal stent  46  may be deployed in a more distal position within the lung passageway LP than desired so that the stent  46  may then be pulled proximally to a desired position with the use of the grasping device  160 . 
     It may further be appreciated that delivery catheters  40  of the present invention may alternatively be provided to a physician or user in a preloaded state wherein one or more occlusal stents  46  are provided within the catheters  40 , ready for delivery. Further, it may be appreciated that automatic loading systems may be provided, or systems in which the stent is pre-connected to the catheter rod but not yet loaded into the catheter receptacle. 
     Methods of Use 
     The occlusal stent delivery system  10  of the present invention may be used for a variety of therapeutic procedures, preferably for performing “endobronchial volume reduction” (EVR). EVR is a non-surgical technique for isolating and occluding diseased lobar and sub-lobar regions of a patient&#39;s lung. An isolated region will be a portion (usually not the whole) of the right or left lung, and volume reduction will be accomplished by evacuating the region and occluding a bronchial passage within or leading to the region with an occlusal stent  46 . One or more bronchial passageways within or leading to the region may be occluded while the region is evacuated, as will be described. 
     Initially, the bronchoscope  12  is separate from the sheath  30  and the distal end  16  of the scope  12  is then introduced through a luer or other proximal connector  34  of the sheath  30 . Referring back to  FIG. 1 , the distal end  16  is advanced until the occlusive member  32  is disposed at a desired position along the length of the scope  12 . At that point, the luer or other connector  34  is then tightened on to the scope  12 . A suitable monitor may then be connected to the bronchoscope  12  in a conventional manner. Inflation of member  32  may be effected through an inflation tube  36 , typically using a pressurized air or other gas source. 
     Referring now to  FIG. 14A , the assembly of the sheath  30  and bronchoscope  12  may be introduced through the trachea T to a target location in a patient&#39;s lung LNG. The sheath-bronchoscope assembly  30 / 12  is introduced so that the occlusive member  32  reaches a desired location, in this example a major takeoff in the left lung. At that point, the member  32  may be inflated. During the advancement and after inflation of the member  32 , viewing through the bronchoscope  12  may be accomplished through the monitor connected to the scope  12 . 
     While the member  32  is inflated, lung segments beyond the member  32  may be evacuated by applying vacuum suction through an aspiration lumen  22  in the bronchoscope  12 . The occlusal stent delivery catheter  40  (having an occlusal stent  46  pre-loaded within its distal end  42 ) is then advanced through the working lumen  18  of the bronchoscope  12 . Forward imaging by the bronchoscope  12  is effected by illuminating through light fibers within the scope lumen  20  and detecting an image through a lens at the distal end  16  of the bronchoscope  12 . The resulting image can be displayed on conventional cathode-ray or other types of imaging screens. In particular, forward imaging permits a user to selectively place the catheter  40  through a desired route through the branching bronchus. It may be appreciated, however, that as an alternative positioning could be done solely by fluoroscopy. 
     In any case, referring again to  FIG. 14A , the delivery catheter  40  is then advanced until its distal end  42  reaches a region in the bronchus or lung passageway which leads directly into a diseased region DR. The delivery catheter  40  is advanced through the working lumen  18  of the bronchoscope  12  via the passageway  108  of the clamp connector  60  attached to the side arm  24   a , as previously described. Once the distal end  42  of the catheter  40  is positioned in a desired location within the lung passageway, the catheter  40  is locked in place with the use of the locking mechanism  64  on the clamp connector  60 . The occlusal stent  46  may then be deployed in the passageway. Recall, the occlusal stent  46  is pre-loaded in a compressed or collapsed state within an interior lumen of the delivery catheter  40 . The occlusal stent  46  is deployed by retracting the tubular shaft  41  of the delivery catheter  40 . This is achieved by sliding the handle button  50  on the handle  48  of the catheter  40 , as previously described. As the tubular shaft  41  retracts, the positioning rod  44  holds the occlusal stent  46  in place. Thus, the occlusal stent  46  is gradually exposed. If the stent  46  is self-expanding, for example by tension or shape-memory, the stent  46  will expand and anchor itself in the passageway as the occlusal stent  46  is exposed, as shown in  FIG. 14A . If the occlusal stent  46  is not self-expanding, it may be expanded with the use of a balloon or other mechanism provided by the delivery catheter  40 , a catheter or device delivered through the catheter  40 , or another device. 
     While the sheath  30  and occlusive member  32  are in place, additional occlusal stents may be positioned within the evacuated lung passageways beyond the member  32 . The delivery catheter  40  may be removed and loaded with a second occlusal stent  46 ′ for reintroduction, or the delivery catheter  40  may be removed and replaced with another delivery catheter  40  that has already been preloaded with a second occlusal stent  46 ′. Referring now to  FIG. 14B , the delivery catheter  40  is then advanced until its distal end  42  reaches a region in the bronchus or lung passageway which leads directly into a second diseased region DR′. Again, the delivery catheter  40  is advanced through the working lumen  18  of the bronchoscope  12  with the use of the clamp connector  60  attached to the side arm  24   a , as previously described. Once the distal end  42  of the catheter  40  is positioned in a desired location within the lung passageway, the catheter  40  is locked in place with the use of the locking mechanism  64  on the clamp connector  60 . The second occlusal stent  46 ′ may then be deployed in the passageway. The second occlusal stent  46 ′ is deployed by retracting the tubular shaft  41  of the delivery catheter  40 . As the tubular shaft  41  retracts, the positioning rod  44  holds the second occlusal stent  46 ′ in place. If the stent  46 ′ is self-expanding, the stent  46 ′ will expand and anchor itself in the passageway as the second occlusal stent  46 ′ is exposed, as shown in  FIG. 14B . 
     Further, while the sheath  30  and occlusive member  32  are in place, any number of additional occlusal stents may also be positioned within the evacuated lung passageways beyond the member  32 . Again, the delivery catheter  40  may be removed and loaded with a third occlusal stent  46 ″ for reintroduction, or the delivery catheter  40  may be removed and replaced with another delivery catheter  40  that has already been preloaded with a third occlusal stent  46 ″ (thus, it may be efficient to utilize two delivery catheters  40  so that one catheter  40  may be preloaded with an occlusal stent while the other is in use). The delivery catheter  40  is then advanced until its distal end  42  reaches a region in the bronchus or lung passageway which leads directly into a third diseased region DR″. Again, the delivery catheter  40  is advanced through the working lumen  18  of the bronchoscope  12  with the use of the clamp connector  60  attached to the side arm  24   a , as previously described. Once the distal end  42  of the catheter  40  is positioned in a desired location within the lung passageway, the catheter  40  is locked in place with the use of the locking mechanism  64  on the clamp connector  60 . The third occlusal stent  46 ″ may then be deployed in the passageway, as shown in  FIG. 14C . 
     The occlusive member  32  may then be deflated and the delivery system  10  removed, leaving the occlusal devices  46 ,  46 ′,  46 ″ behind wherein each occlusal device isolates and occludes a diseased region DR, DR′, DR″, respectively. 
     Although the foregoing invention has been described in some detail by way of illustration and example, for purposes of clarity of understanding, it will be obvious that various alternatives, modifications and equivalents may be used and the above description should not be taken as limiting in scope of the invention which is defined by the appended claims.