Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a Continuation of application Ser. No. 10/379,591, filed Mar. 6, 2003, now U.S. Pat. No. 6,767,338 which is a Continuation of application Ser. No. 09/695,527, filed Oct. 24, 2000, now U.S. Pat. No. 6,582,400 both of which are included herein in their entirety by reference. 

   FIELD OF THE INVENTION 
   The claims of the present invention are directed towards medical devices. More specifically, the claims of the present invention are related to catheters, endoscopes, and other medical devices with function distal ends that may be used to perform medical procedures within the body of a patient. 
   BACKGROUND OF THE INVENTION 
   A number of techniques are available for treating cardiovascular disease such as cardiovascular bypass surgery, coronary angioplasty, coronary atherectomy, and stent placement. These techniques are generally performed to bypass or open lesions in coronary vessels to restore patency and increase blood flow to the heart muscle. In some patients, the number of lesions are so great, or the locations so remote in the coronary vasculature, that restoring coronary artery blood flow to the heart is difficult. Transmyocardial revascularization (TMR), also known as percutaneous myocardial revascularization (PMR), has been developed as an alternative to these techniques which are directed to bypassing or removing lesions. 
   Heart muscle may be classified as healthy, hibernating, and “dead.” Dead tissue is not dead but is scarred, no longer contracting, and no longer capable of contracting even if adequately supplied with blood. Hibernating tissue is not contracting muscle tissue but is capable of contracting again, provided it is once more adequately supplied with blood. PMR is performed by wounding the myocardium of the heart, often forming and leaving patent holes, and sometimes injecting angiogenic substances in the process. 
   PMR was inspired in part by observations that reptilian hearts are largely supplied by blood directly from within the heart chambers. In contrast, mammalian hearts are supplied by blood pumped from the heart, through the aorta, and back to the heart muscle through the coronary arteries. Positive results have been observed in some patients receiving PMR treatments. The positive results may be due in part to blood being perfused into the myocardium from within the heart chambers through holes into the myocardium. The positive results are believed to be due in part to a wound healing response of the myocardium which includes formation of new blood vessels in the heart wall, which are believed to connect with the heart chamber interior and/or other coronary blood vessels. The PMR procedure can include cutting into the myocardium with therapeutic tips or burning holes with therapeutic tips having laser or radio-frequency current tips. PMR therapeutic tips can also be used to inject angiogenic substances such as growth factors or genes selected to induce angiogenesis. 
   The PMR procedure generally involves insertion of a therapeutic tip such as a sharp cutting tip into the heart chamber or chambers selected for treatment. The cutting tip and associated inner shaft can be guided into the chamber within a guide catheter, which may have been inserted into the vasculature a long distance from the heart. After the inner shaft distal end exits the guide catheter, the cutting tip is preferably steered to several positions for formation of several holes in a pattern across the endocardium. In order to steer the inner shaft and cutting tip, an outer shaft or tube is sometimes disposed coaxially about the inner shaft and within the guide catheter. The outer tube can have structural features at the distal end for bending to various angles to reach various locations in the heart wall. The outer tube and inner shaft can be cooperatively advanced to bring the cutting tip into contact with the heart wall. 
   To allow passage through the guide catheter, the outer tube should have a sufficiently small radial or transverse profile over its length. As with many catheter devices, a small profile is desirable to allow passage through tortuous and narrow vessels. At the outer tube distal end, however, a small profile can also mean a small profile presented to the heart wall when inserting a cutting tip. It may be desirable to bring the outer tube very close or even into contact with the heart wall. While inserting a cutting tip into the heart wall may be desirable, inserting the larger outer tube distal end into the heart wall may be undesirable. 
   What is desirable is an improved guide device for steering inner shaft cutting tips into position within the heart myocardium. The improved guide device would preferably include a distal end having a small profile for passage through a guide catheter, yet having a larger profile for presentation to the heart inner wall to limit undesirable penetration by the guide device distal end. 
   SUMMARY OF THE INVENTION 
   The present invention includes devices for performing percutaneous myocardial revascularization (PMR) that can lessen the likelihood of a shaft distal end penetrating undesirably into the myocardium. In one application, PMR devices are used to penetrate the endocardium and myocardium to a controlled depth. One group of devices according to the present invention includes an inner shaft having a therapeutic tip, for example, a distal cutting tip. The inner shaft can be disposed within an outer tube or shaft lumen, and the outer shaft can be disposed within the lumen of a guide catheter. Preferably, the myocardium. is penetrated by the cutting tip of the inner shaft but not by any larger profile outer shafts or tubes disposed about the inner shaft. The outer shaft distal region preferably has a first configuration having a small radial extent or profile allowing disposition of the outer shaft within a small guide catheter. The outer shaft distal region preferably also has a second configuration having a larger radial extent or profile for presentation against the endocardium. While having the larger profile, the outer tube distal end has increased resistance to penetrating the heart wall. The larger surface presented to the heart wall while in the radially expanded position forms a more atraumatic distal end for the outer tube distal end. 
   The outer tube distal end can have an atraumatic distal hood or tip that is formed of an elastic material that can be benignly forced against an obstacle such as the heart chamber inner wall, the endocardium. The atraumatic hood allows passage of the therapeutic tip therethrough to contact the heart wall. The atraumatic hood preferably has a sufficiently small profile so as to fit within an enclosing guide catheter in a first configuration. In one embodiment, the atraumatic hood is sufficiently elastic to longitudinally foreshorten and radially expand to attain a larger profile or radial extent when forced against the endocardium. The radially enlarged hood presents a larger transverse surface area to the heart wall and inhibits penetration of the heart wall by the outer shaft distal end. In one embodiment, the atraumatic hood has a bulbous shape and has a distal-most orifice for receiving the cutting tip of a slidably disposed inner therapeutic shaft. 
   One outer shaft atraumatic tip includes a distally disposed elastic member having a first, constrained configuration, and a second, unconstrained configuration. In a constrained configuration, which may occur when the tip is constrained within an enclosing guide catheter, the tip has a radial extent or profile that fits within the guide catheter. In an unconstrained configuration, the tip can expand to a larger radial extent or profile, where the radial extent is preferably larger than the outer diameter of the guide catheter. One atraumatic tip includes an elastomeric disk or washer transversely disposed to the longitudinal axis of the catheter. Another atraumatic tip includes several radially disposed segments or arms. In use, the atraumatic tip can expand radially outward when advanced from a guide catheter, and can radially contract when retracted back within the guide catheter. 
   Another outer shaft atraumatic distal end or stop includes a spring wound about the outside of the outer shaft distal region. The spring preferably has a constrained configuration when contained within an enclosing guide catheter. When advanced distally from the guide catheter, the spring preferably expands radially to a second, unconstrained configuration having a larger profile. The larger profile can present a hindrance to penetration of the endocardium by the distal end of the outer shaft. After use of any inner therapeutic shaft, the outer shaft can be retracted within a guide catheter, again constraining the distal spring and reducing the radial extent. In one embodiment, the spring is formed as a helical coil. In another embodiment, the spring is formed as a ribbon or clock spring disposed about a relatively short length of the outer shaft. 
   One device outer shaft includes an atraumatic distal region formed as an inflatable member having a small, uninflated profile and a large, inflated profile. The shaft can include an inflation lumen and the inflatable member can include an inflatable balloon having an interior in fluid communication with the inflation lumen. The distal inflatable member can be inserted uninflated within a guide catheter for delivery to a target site such as the endocardium. After advancing the distal inflatable member from a guide catheter, inflation fluid can be supplied through the inflation lumen and into the inflatable member, thereby increasing the radial extent of the inflatable member. The inflated member or balloon can present a larger distal transverse surface area, which presents an inhibition to penetration of the endocardium by the outer shaft distal end. One device has a dual lumen shaft with side-by-side lumens. Another device has an inflation lumen coaxially disposed about an inner lumen which can be used for delivery of a therapeutic inner shaft. 
   One device has a distal cross member having a first, transverse orientation, and a second, more longitudinal orientation. The cross member is preferably pivotally mounted to a distal-most portion of the outer tube. The cross member can have a first arm for attachment to an elongate manipulation member and a second, opposite arm having an opening for allowing passage of a therapeutic inner shaft through the transversely disposed cross member. In one embodiment, the cross member is biased to remain in a substantially transverse orientation to the longitudinal axis of the outer tube. In one embodiment, the attached cross member arm can be either pushed or pulled with the elongate manipulation member. In some embodiments the elongate manipulation member is capable of effectively pulling the cross member to a transverse position, but not of pushing the cross member arm to a smaller profile, more longitudinal orientation. In other embodiments, the elongate manipulation member is capable of both pushing and pulling the cross member between small and large profile orientations. 
   In yet another embodiment, the outer tube has distally disposed wings or fins having a first, closed position, and a second, open position. In the closed position, the wings can lie closely about the outer tube distal region outer walls, presenting a small transverse profile. In the open position, the wings can extend radially outward, presenting a large transverse profile. The wings can be biased to expand to the larger profile configuration when unconstrained by a guide catheter. In one embodiment, the wings are formed of a shape memory material, for example Nitinol, and expand to the larger profile configuration when warmed to body temperature. In use, the wings expand to present a large profile to the endocardium or other surface. The wings can be forced to contract when the outer shaft distal end is retracted within a guide catheter having a smaller inside diameter than the radial extent of the distal wings. 
   In still another embodiment, the outer tube has a distal region which can be followed distally by a distal end which can be terminated more distally by a distal-most portion. The distal end can include an outer tube wall region having several longitudinally disposed slits or slots defining wing regions therebetween. The wing regions can include preferential folding locations. An inner tube or shaft can be slidably and coaxially disposed within the outer tube and secured to the outer tube distal-most portion. The PMR device having the inner and outer tubes can be distally advanced from a guide catheter and the inner tube moved proximally relative to the outer tube, thereby applying a proximal pulling force on the outer tube distal-most portion. The applied force can force the longitudinal wings between the longitudinal slots to buckle and splay radially outward, longitudinally foreshortening the outer tube distal end in the process. The radially outwardly splayed wings can present a larger radial extent or profile to the endocardium and inhibit penetration of the endocardium by the outer tube. After use, the inner tube can be advanced relative to the reduced profile device and retracted within a guide catheter. 
   In another embodiment a therapeutic catheter includes an outer tube having a distal region, a distal end, a tube wall, and a first lumen within the outer tube. The outer tube distal end is preferably sufficiently sharp to penetrate into the endocardium. A stop can be disposed within the outer tube, defining a smaller inside diameter region in a proximal portion of the outer tube distal region. A plug disposed within the outer tube first lumen distal region preferably has a maximum outer dimension too large to allow proximal movement past the stop. When the sharp distal end penetrates into the myocardium, the penetration is limited by the myocardium contacting the plug, which can in turn be contacting the stop or shoulder. The stop can be an annular stop, defined by an integrally formed annular stop in one embodiment and by the distal end of an inserted inner tube in another embodiment. 
   In one therapeutic catheter for increasing myocardial blood perfusion, the outer tube wall has at least one substance delivery lumen disposed within and at least one injection port disposed near the outer tube distal end. In another therapeutic catheter an inner tube has a substance delivery lumen and a distal end, the inner tube being disposed within the outer tube. A plug having a lumen therethrough for receiving the inner tube can be slidably disposed within the outer tube, such that the inner tube distal end forms a distal shoulder for limiting proximal travel of the plug. In one embodiment, the inner tube distal end is sufficiently sharp to penetrate into the myocardium and extends distally past the plug when the plug abuts the shoulder. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a cutaway, perspective view of a human heart having a PMR therapeutic tip catheter disposed within a guide catheter in the left ventricle; 
       FIG. 2  is fragmentary, longitudinal, cutaway view of a PMR device having an outer tube and an inner therapeutic shaft with therapeutic tip disposed therein; 
       FIG. 3  is a fragmentary, longitudinal cross-sectional view of a PMR device extending from a guide catheter and having an elastically radially expandable atraumatic tip bonded to the PMR device outer tube; 
       FIG. 4  is a fragmentary, longitudinal cross-sectional view of the device of  FIG. 3  forced against the endocardium, with the inner shaft penetrating the myocardium and the atraumatic tip radially expanded; 
       FIG. 5  is a fragmentary, longitudinal cross-sectional view of a PMR device extending from a guide catheter and having an elastically radially expandable atraumatic tip bonded to the outside of PMR device outer tube; 
       FIG. 6  is a fragmentary, longitudinal cross-sectional view of a PMR device extending from a guide catheter and having an elastically radially expandable atraumatic tip bonded to the inside of the PMR device outer tube; 
       FIG. 7  is a fragmentary, longitudinal cross-sectional view of a PMR device disposed within a guide catheter and having an elastically radially expandable atraumatic distal flange constrained within the guide catheter; 
       FIG. 8  is a fragmentary, longitudinal cross-sectional view of the PMR device of  FIG. 7  extending from within the guide catheter and having the expandable atraumatic distal flange radially extended; 
       FIG. 9  is a fragmentary, longitudinal cross-sectional view of the PMR device of  FIG. 7  retracted within the guide catheter and having the atraumatic distal flange radially constrained within the guide catheter; 
       FIG. 10  is an end view of the PMR device atraumatic distal flange of  FIG. 8 ; 
       FIG. 11  is an end view of a PMR device atraumatic distal flange having radial slits; 
       FIG. 12  is an end view of a PMR device atraumatic distal flange having radial arm segments; 
       FIG. 13  is a fragmentary, longitudinal cross-sectional view of a PMR device outer tube disposed within a guide catheter and having a radially expandable distal spring constrained within the guide catheter; 
       FIG. 14  is a fragmentary, longitudinal cutaway view of the PMR device outer tube of  FIG. 13  extending from the guide catheter and having the spring radially expanded; 
       FIG. 15  is an end view of a PMR device outer tube having a ribbon spring wound around the outer tube; 
       FIG. 16  is a fragmentary, longitudinal cross-sectional view of a PMR device outer tube having dual lumens and having a distal inflatable atraumatic tip; 
       FIG. 17  is a fragmentary, longitudinal cross-sectional view of a PMR device outer tube having coaxial lumens and having a distal inflatable atraumatic tip in an inflated configuration; 
       FIG. 18  is a fragmentary, longitudinal side view of a PMR device having a distal, atraumatic pivotally mounted cross member, with a manipulation member drawn in phantom within the PMR device outer tube; 
       FIG. 19  is a fragmentary, longitudinal cross-sectional view of the PMR device of  FIG. 18  having the distal cross member in a transverse position; 
       FIG. 20  is a fragmentary, longitudinal, cross-sectional view of a PMR device outer tube having a distal, atraumatic, pivotally mounted and offset cross member; 
       FIG. 21  is a fragmentary, top view of one possible offset mounting for the cross member of  FIG. 21 ; 
       FIG. 22  is an end view of the outer tube of  FIG. 19 , with the cross member in a transverse position; 
       FIG. 23  is a fragmentary, perspective view of a PMR device outer tube having expandable distal wings in a contracted configuration; 
       FIG. 24  is an end view of the wings of the device in  FIG. 23 ; 
       FIG. 25  is an end view of the wings of the device in  FIG. 23  in an expanded configuration; 
       FIG. 26  is a fragmentary, perspective view of a PMR device having a slidable, coaxially disposed inner tube within an outer tube having a distal. end with longitudinal slits; 
       FIG. 27  is a fragmentary, perspective view of the outer tube of the device of  FIG. 26  having the inner tube retracted and the distal end expanded to form an atraumatic tip; 
       FIG. 28  is an end view of the outer tube of  FIG. 27  in the expanded configuration; 
       FIG. 29  is a fragmentary, longitudinal cross-sectional view of a PMR device including an inner tube, an outer tube having a lumen within the wall with a sharp distal end serving as a delivery needle, and a hood stop, the sharp distal end shown abutting the endocardium; 
       FIG. 30  is a fragmentary, longitudinal cross-sectional view of the PMR device of  FIG. 29 , the sharp distal end shown penetrating the endocardium up to the hood stop now abutting the inner tube distal end; 
       FIG. 31  is an end view of the PMR device of  FIG. 29 , illustrating the hood stop within the outer tube, with injection holes shown in the outer tube distal end; 
       FIG. 32  is a fragmentary, longitudinal cross-sectional view of a PMR device including an inner tube having a delivery lumen within, an outer tube having a lumen within the wall with a sharp distal end serving as a penetrating needle, and a hood stop, the sharp distal end shown abutting the endocardium; 
       FIG. 33  is a fragmentary, longitudinal cross-sectional view of the PMR device of  FIG. 32 , the sharp distal end shown penetrating the endocardium up to the hood stop now abutting an inner shoulder within the outer tube; 
       FIG. 34  is a fragmentary, longitudinal cross-sectional view of a PMR device inner shaft having a flexible atraumatic flange stop, illustrated after being distally extended from a guide catheter; 
       FIG. 35  is a fragmentary, longitudinal cross-sectional view of a PMR device inner shaft having an expandable atraumatic spring stop, illustrated prior to being distally extended from a guide catheter; and 
       FIG. 36  is a fragmentary, longitudinal cross-sectional view of a PMR device within a guide catheter. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  illustrates a human heart  40  having a guide catheter  50  inserted through the aortic arch  42  and into the left ventricle  44 . Guide catheter  50  is shown having a therapeutic catheter  52  extending therethrough terminating in a therapeutic catheter therapeutic tip  54 . Therapeutic tip  54  can be used to form a plurality of holes  46  in left ventricle wall  48 . Therapeutic tip  54  can be used to form holes in order to stimulate a healing, response as well as to inject angiogenic substances such as VEGF and other factors well-known in the art. As can be seen from inspection of  FIG. 1 , the depth of holes  46  in left ventricle wall  48  are important as the holes should optimally not penetrate through the entire wall thickness of the myocardium. As further explained below, therapeutic catheter  52  is often not directly disposed within guide catheter  50 . In particular, therapeutic catheter  52  may be disposed within an enclosing outer tube coaxially disposed between therapeutic catheter  52  and guide catheter  50 . 
     FIG. 2  illustrates generally a PMR device  60 , including a distal. end  63  and a distal portion  62  having an outer tube  64  having a lumen  65  therein. Device  60  is an example of a PMR device suitable for inclusion of the present invention. In particular, the distal profile of device  60  may be configurably expanded by incorporating various embodiments of the present invention. A second, inner tube or shaft  66  is disposed within lumen  65  extending to a therapeutic tip region  70  terminating in a sharp, cutting end  72  in the embodiment illustrated. Inner tube  66  may be slidably disposed within an outer tube  64 . The embodiment illustrated further includes a tip  68  terminating outer tube  64 . Inner tube  66  may be formed of a hypotube material and may include a swage collar  74  to limit travel of inner shaft  66 . As further discussed below, outer tube distal end  63  and/or distal tip may have the profile or radical extent configurably increased. 
     FIG. 3  illustrates a device  100  including a guide catheter  104  having a PMR device  105  disposed therein. As can be seen from inspection of  FIG. 2 , PMR device  105  has a maximum relaxed outer diameter of D 2 , which may be compared to the inside diameter of guide catheter  104 , D 1 . The relatively small outer diameter or profile of device  105  allows the device to fit within guide catheter  104 . Device  105  includes an outer wall or tube  102  and a distal region  106 . Distal region  106  includes an outer wall  107  bonded at  108  to outer tube  102 . An inner shaft or therapeutic catheter  112  is disposed within a lumen  113  within outer tube  102 . Therapeutic catheter  112  terminates distally in a therapeutic catheter therapeutic tip  114 . Therapeutic tip  114  may have a sharp cutting end and can include means for injecting substances into the heart wall. In one embodiment, inner shaft  112  is a tube having a lumen therethrough. Therapeutic catheter  112  may be seen to extend through a brush or flange region  110 . Distal region  106  terminates distally in a distal orifice  116 . As can be seen from inspection of  FIG. 3 , the wall thickness of distal region  106  is thinner distally than proximally. In some embodiments, distal orifice  116  is not formed until the distal-most region of distal region  106  is perforated by therapeutic tip  114 . This perforation can occur as the result of advancing a slidably disposed cutting tip through the distal-most region and/or by pressing the distal-most region against an obstacle such as the heart wall. 
     FIG. 4  illustrates device  105  disposed against a portion of the heart wall  117 . Therapeutic tip  114  may be seen to have penetrated well into the heart myocardium  109 . As distal region  106  is forced against the heart wall, the maximum radial extent or profile of the device may be seen to increase, as indicated at D 3 .  FIG. 4  illustrates a configuration in which device  105  has not been fully pressed against the heart wall. As illustrated by  FIG. 4 , the bulbous distal region  106  is splayed radially outward by compression against the heart wall. In some embodiments, the depth of penetration of therapeutic tip  114  is limited primarily by the outward splaying of distal region  106 . In some embodiments, therapeutic catheter  112  may be relatively fixed within outer tube  102 . In such embodiments, the travel of therapeutic tip  114  into the heart wall is limited by the geometry of distal region  106 . 
   As illustrated by  FIG. 4 , the outer profile presented by the compressed or splayed distal region  106  is substantially greater than the profile presented within the guide catheter.  FIG. 4  thus illustrates device  106  having only a small profile while within the guide catheter and a larger profile when presented against the heart wall, thereby presenting a travel limiting, outwardly splayed larger profile surface. Distal region  106  can be formed of a polymeric material, preferably one having sufficient elastomeric properties so as to return to the configuration illustrated in  FIG. 3  after being splayed outward against the heart wall, as illustrated in  FIG. 4 . 
     FIG. 5  illustrates another embodiment device  130  in which the distal region includes an outer distal region wall  134  disposed over the outside of a tube wall  136  and bonded thereto at  137 . As in  FIG. 3 , device  130  includes a brush or flange region  132  disposed within  134 .  FIG. 6  illustrates yet another embodiment device  140  in which the distal region walls  144  are disposed within outer tube wall  146  and bonded thereto at  147 . In the embodiment illustrated, the distal region walls  144  are narrowed in throat region  142  which can serve as a brush for receiving a therapeutic catheter tip therethrough. As can be seen from inspection of  FIGS. 3–6 , the distal regions of the devices are radially expanded and longitudinally foreshortened by contact with the heart wall. The force of compression against the heart wall is the primary causative factor in expanding the distal regions of the devices radially. 
     FIG. 7  illustrates yet another PMR device  160  having an outer tube  166  terminating in a distally disposed flange  168 . Flange  168  includes an orifice  164  therethrough for receiving therapeutic catheter  66 . Flange  168  includes outward extent  170 , illustrated as bent alongside outer tube  166 , within guide catheter  104 . While constrained within guide catheter  104 , flange  168  has a small transverse profile. 
   Referring now to  FIG. 8 , PMR device  160  has been distally forced from the constraint of guide catheter  104 . Outermost extent  170  of flange  168  may be seen to have expanded radially. Flange  168  now has a radial extent or profile larger than the radial extent or profile of guide catheter  104 . Flange  168  may be formed of an elastomeric material such as siliconized rubber, Tecoflex, Tecothane, or 80A Pellathane. Flange  168  may be formed of soft polymers with or without radiopaque loading or coating. In one embodiment, flange  168  includes mounting or bonding arms  172  bonded to outer tube  166 . When pressed against the heart wall, flange  166  can present a very large profile for reducing the likelihood of outer tube  166  penetrating into the heart wall. After use, as illustrated  FIG. 9 , outer tube  166  and attached flange portion  168  can be retracted proximally back within guide catheter  104 . In this configuration again, flange portion  168  has a reduced outer profile or radial extent. This allows PMR device  160  to be retracted through the guide catheter. 
     FIG. 10  illustrates a transverse, end view of one embodiment of PMR device  160 , illustrating distal flange portion  168 . In the embodiment illustrated, distal flange portion  168  is a substantially continuous washer having orifice  162  therethrough. Referring now to  FIG. 11 , a distal flange portion is formed of a plurality of slits  180  defining a plurality of segments  182  therebetween.  FIG. 12  illustrates yet another embodiment of a distal flange portion having a plurality of separated arms  184  disposed about a central orifice  164 . As can be seen from inspection of  FIGS. 7 through 12 , the expandable tip portion operates by having a distal flange which is biased to assume a large radial extent or profile when in the unconstrained position. When constrained by guide catheter  104 , the distal flange portion is constrained to a smaller profile configuration. 
     FIG. 13  illustrates yet another PMR device  200 . PMR device  200  includes an outer tube  202  for receiving a therapeutic catheter therethrough. Disposed about tube  202  is a spring  204  formed as a coil. Spring  204  is bonded or otherwise affixed to the outside of outer tube  202 . In the embodiment shown, spring,  204  is formed as a spiral, helical coil configuration having substantially constant radial extent over the longitudinal extent of spring  204 . As can be seen from inspection of  FIG. 13 , coil  204  is constrained within the inner wall of guide catheter  104 .  FIG. 13  illustrates the configuration of spring  204  prior to advancing outer tube  202  toward the heart wall. Referring now  FIG. 14 , PMR device  200  is illustrated after being advanced distally out of guide catheter  104 . Spring  204  may be seen to have expanded to a larger radial extent or profile, and to have extended distally as well. In particular, the outer profile of spring  204  may be seen to be larger than the inner and even outer diameter of guide catheter  104 . By affixing the proximal portion of spring  204  to outer tube  202 , a spring having a potentially large outer profile may be wound onto an outer tube and constrained within guide catheter  104 . In the embodiment illustrated, spring  204  expands radially due to the bias of the spring elements. While a preferred embodiment has a spring extending over a length of outer tube as illustrated as a helical coil or spring, other embodiments are possible.  FIG. 15  illustrates other embodiment in which a spring  210  is affixed to outer tube  202  and configured as a spiral-wound ribbon wound about the outer tube. In one embodiment, spring  210  is formed in a spiral shape resembling a clock spring. 
   In use, after advancing spring  204  from guide catheter  104 , the spring will present an enlarged distal region to prevent unwanted penetration of the heart wall by outer tube  202 . After disposing spring  204  against the heart wall, a therapeutic catheter tip as previously illustrated may be advanced through tube  202  and into the heart wall. After use, spring  204  can be retracted proximally back within guide catheter  104 , again reducing the profile. In some embodiments, spring  204  may be wound within guide catheter  104  by rotating outer tube  202  while retracting outer tube  202  into guide catheter  104 . In other embodiments, outer tube  202  may be simply retracted into guide catheter  104 . In some embodiments, designed for a single deployment of spring  204 , the retraction of spring  204  into guide catheter  104  may deform the spring, reducing the elastic ability of spring  204  to expand to a large radial extent the second time. In particular, in some embodiments, after use, spring  204  may be retracted within guide catheter  104 , forming an elongate very long spiral coil relative to the original relatively compact coil. 
     FIG. 16  illustrates a PMR device  220 , including, an outer tube  236  having an internal tube wall  238  therein. Outer tube  236  includes a first lumen  222  for receiving therapeutic catheter  66 . Outer tube  236  also includes a second lumen  224 . The distal region of device  220  includes an inflatable balloon  226  having balloon interior  228  therein. Balloon interior  228  is in fluid communication through an inflation orifice  234  through outer tube  236  and in communication with second lumen  224  which can serve as an inflation lumen. Second or inflation lumen  224  is seen to be plugged distally by a plug  230 . Balloon  226  may be seen to be bonded at  232  to outer tube  236 . In use, device  222  may have balloon  226  uninflated and even pulled under vacuum to fully retract balloon  226  to a low profile configuration. Device  220  may then be disposed in a guide catheter. After being advanced to a location near the heart wall, device  220  may be advanced distally from the containing guide catheter. A suitable inflation fluid may be injected into second lumen  224  and thereafter into balloon interior  228 . Balloon  226  may be expanded to attain a large distal profile for device  220 . With a large profile presented, the likelihood of outer tube  236  being forced undesirably into the heart wall is greatly reduced. Once inflated, therapeutic catheter  66  may be forced against the heart wall. 
   Referring now  FIG. 17 , another embodiment of a PMR device is illustrated in a device  260  having a tip having a distal inflatable balloon. Device  260  includes inflatable balloon  227  having interior  229  affixed to an outer tube  262 . Disposed within outer tube  262  is an inner tube  264 , coaxially disposed within tube  262 . PMR device  260  includes a first lumen  266  for receiving a therapeutic catheter, and a second or inflation lumen  268  coaxially defined between inner tube  264  and outer tube  262 . Balloon  227  may be seen to be bonded at  272  to inner tube  264 , and is illustrated in an inflated state. 
   Referring now to  FIGS. 18–21 , another PMR device  300  is illustrated having a shaft  301  having a distal region  302  and a distal end  304 . Distal end  304  has a cross member  310  pivotally mounted at  312 , where pivot mount  312  is preferably transversely disposed to the longitudinal axis of shaft  301 . Cross member  310  has a first arm  311  secured to an elongate manipulation member  318 . Cross member  310  has a second arm  314  having an opening or passageway  316  disposed therethrough. Shaft  301  has a first lumen  306  therethrough for receiving a therapeutic catheter and a second lumen  308  therethrough for receiving elongate cross member manipulation member  318  within. 
     FIG. 19  illustrates a longitudinal wafer cut through the center of device  300  and having a therapeutic inner shaft  320  disposed within first lumen  306 . Opening  316  in cross member second arm  314  is positioned for receiving inner shaft  320  therethrough. As can be seen from inspection of  FIG. 19 , cross member  310  is disposed in a configuration oriented transversely to the longitudinal axis of device shaft  301 . In this orientation, cross member  310  presents a profile or radial extent greater than the outside diameter of shaft  301 . The larger profile can serve to inhibit penetration of the myocardium by shaft  301 . In the embodiment illustrated, a central wall portion  322  separates first lumen  306  from second lumen  308 . A spring or bias element  324  is affixed to both central wall portion  322  and cross member  310  so as to bias the cross member in a substantially transverse orientation. In embodiments having a transversely biased cross member, elongate manipulation member  318  can be a pull wire capable of being pulled for tension, but weak in compression. In embodiments not having a transverse bias for the cross member, elongate manipulation  318  is preferably sufficiently strong in compression to push the cross member to a transverse orientation. The inside diameter of second lumen  308  and elongate manipulation member  318  can be cooperatively sized to provide support in compression for the elongate manipulation member. 
     FIG. 20  illustrates a PMR device  330  similar in many respects to PMR device  300 , but having cross member  310  pivotally mounted on an offset member  332  and rotatably secured to a pivot member  324 . Offset member  332  can be formed of longitudinally oriented end members allowing cross member  310  to lie between the end members to achieve a substantially longitudinal orientation. As can be seen in  FIG. 21 , a top view of offset member  324  without having cross member  310  mounted, a pair of end members  333  can have cross member  310  mounted on pivot pin  310  between the end members.  FIG. 22  illustrates a transverse cross-sectional view showing cross member  310  mounted about central wall  322  and having opening  316  therethrough. 
   Referring now to  FIG. 23 , another PMR device  350  is illustrated having an outer tube  352  having a distal end  354  and having a lumen  360  therethrough which can be used to receive a therapeutic inner shaft. Several expandable members or wings  356  are secured to outer tube  352  at distal end  354 . Distal wings  356  are illustrated in a first configuration having a sufficiently small profile or radial extent to fit within an enclosing guide catheter. In one embodiment, distal wings  356  are formed of a shape memory material having a first, small radial extent at a lower temperature and a second, large radial extent at a higher temperature such as body temperature. In another embodiment, distal wings  356  are formed of a material biased to expand upon release from the constraining guide catheter. In some embodiments, distal wings  356  are formed of a metal, for example, Nitinol. In other embodiments, distal wings  356  are formed of polymeric materials.  FIG. 24  illustrates a distal end view of outer tube  352  having wings  356  in a small profile configuration.  FIG. 25  illustrates distal wings  356  in a second, large profile configuration. 
   In use, distal wings  356  can be disposed within a constraining guide catheter and advanced to a target site. Outer shaft  352  can be advanced from within the guide catheter, allowing distal wings  356  to deploy radially outward. When distal end  354  is pressed against the heart wall, wings  356  can present a larger profile object to inhibit the penetration of the distal end into the heart wall. After use, distal end  354  can be retracted back into a guide catheter. In one method, outer tube  352  is rotated as the tube is retracted within the guide catheter, urging the wings to lie close to or wrap about outer tube distal end  354 . In one embodiment, the guide catheter distal end includes an internal guide groove or other structure to urge the wings to reform a curved shape about the outer tube outer wall. 
   Referring now to  FIGS. 26–28 , another PMR device  380  is illustrated having a shaft  381  having a distal region  382 , a more distal, distal end  384 , and a still more distal, distal-most portion  386 . Shaft  381  includes a lumen  395  for receiving a shaft therethrough. Distal region  384  has several longitudinal slits or slots  388  formed through the wall of outer tube  381 . Slits  388  define several wings  390  therebetween. In the embodiment illustrated, wings  390  have a region for preferential folding, such as weakened area  392 . Distal end  384  is designed to longitudinally buckle under an applied force, thereby longitudinally foreshortening the distal end and radially expanding the radial extent or profile of the distal end. The applied force can come from a compressive force of being forced against the heart wall and/or a force applied by a longitudinal elongate member disposed within outer tube  381  and secured at the distal end to distal-most portion  386 . In the embodiment illustrated, an inner tube  396  is slidably disposed within lumen outer tube lumen  395 . Inner tube  396  has a lumen  397  therethrough for receiving a shaft with therapeutic tip. Inner tube  396  can be secured to outer tube  381  at distal-most portion  386 . 
     FIG. 27  illustrates PMR device  380  in a radially expanded configuration in which inner tube  396  has been proximally retracted relative to outer tube  381 , longitudinally foreshortening and radially expanding distal end  384 .  FIG. 28  illustrates an end view of PMR device  380 . Wings  390  may be seen to be significantly radially expanded relative to the configuration illustrated in  FIG. 26 . The expanded, increased profile distal end presents a larger transverse surface area and offers an impediment to distal end  384  penetrating the heart wall. 
   The outer tubes and coupled atraumatic distal tips discussed are believed suitable for use in limiting unwanted penetration of the endocardium while allowing disposition within a more outer tube, for example, a guide catheter. The scope of the invention is of course not limited to these uses. The present invention can be used as part of many devices and in many applications where a small profile is desired in a first configuration and a larger profile is desired in a second configuration. Devices incorporating the present invention may be used to advantage anywhere a small distal profile is desired, including some devices used for direct passage within the body, rather than used for passage through enclosing tubes or guide catheter. 
   Referring now to  FIG. 29 , a PMR device  400  is illustrated, having an outer tube  410  disposed about an inner tube  414  and having a plug or hood stop  420 . PMR device  420  is illustrated abutting endocardium  408 . Inner tube  414  has a lumen  416  therethrough and a distal end  418 , which can serve to limit the proximal travel of hood stop  420 . Outer tube  410  has a distal region  404 , a sharp distal tip  406 , and an intermediate region  402 . Outer tube  410  has a wall having a lumen  412 , the space within which can serve as a therapeutic substance delivery lumen. Sharp distal end  406  can serve as a needle for injecting a therapeutic substance through distal holes  428  (shown in  FIG. 31 ). Hood stop  420  includes a large outer diameter distal region  426 , a shoulder region  424 , and a small outer diameter proximal region  422 . Outer tube  410  has an inside diameter in distal region  404  sufficiently large to accommodate hood stop  420 , with inner tube distal end  418  serving as a stop or shoulder and having an inside diameter sufficiently small to limit the proximal travel of hood stop  429 . In some embodiments, distal region  404  has a distally decreasing inside diameter, such that hood stop  420  is precluded from exiting outer tube  410  distally. In one embodiment, the stop or shoulder is formed by a region of decreased inside diameter integrally formed with the outer tube, similar to outer tube  442  of  FIG. 30 . 
   Referring now to  FIG. 30 , PMR device  400  is illustrated after penetrating endocardium  408 . Outer tube distal end  406  has penetrated into endocardium.  408 , thereby penetrating injection holes  428  (shown in  FIG. 31 ) into the heart wall. Penetration of outer tube distal end  406  is limited by stop  420  which can now abut endocardium  408  on the distal side and abut inner tube distal end  418  on the proximal side with shoulder region  424 . Outer tube wall lumen  412  can be used to inject a therapeutic substance into the heart wall through distal end  406 .  FIG. 31  illustrates an end view of PMR device  400 , illustrating injection holes  428  in outer tube distal end  406 , distal stop  420 , and outer tube  410 . Outer tube  410  and inner tube  414  can be formed of materials previously discussed, for example hypotube or polymeric materials. 
   Referring now to  FIG. 32 , a PMR device  440  is illustrated, having a outer tube  442 , an inner tube  456 , and a plug or hood stop  470 . PMR device  440  is illustrated abutting endocardium  408 . Inner tube  456  has a distal end  458  and a delivery lumen  460  within. In some embodiments, distal end  458  is sharp and has a length intended to penetrate into the heart wall through hood stop  470 . In other embodiments, distal end  458  is dull and has a length intended to remain within hood stop  470  when the PMR device has penetrated into the heart wall. Delivery lumen  460  can be used to inject or infuse a therapeutic substance. Outer tube  442  includes a sharp distal tip  448 , a distal region  446 , and an intermediate region  444 . Outer tube  442  includes a shoulder region  452  disposed proximal of a larger inside diameter region  450  and distal of a smaller inside diameter region  454 . Hood stop  470  includes a distal large outer diameter region  472 , an annular ring portion  471 , a shoulder region  474 , and a proximal small outer diameter region  478 . Hood stop  470  can also include a lumen  476  extending through the stop, allowing some penetration of inner tube distal end  458  past the distal face of the stop and into the heart wall, to aid in injecting a therapeutic substance into the heart wall. In some embodiments, distal region  446  has a distally decreasing inside diameter, such that hood stop  470  is precluded from exiting outer tube  442  distally. 
   Inner tube lumen  460  can be used to inject a therapeutic substance into the heart wall past distal end  458 . Outer tube  442  and inner tube  456  can be formed of materials previously discussed, for example hypotube or polymeric materials. Hood stop  470  can be formed of atraumatic polymeric materials, previously discussed. 
   Referring now to  FIG. 34 , a PMR device  500  is illustrated disposed within guide catheter  104 , having inner tube or shaft  66  with therapeutic tip region  70  and terminating in cutting tip  72 , as discussed with respect to  FIG. 2 . PMR device  500  also has a flange or stop  502 , which can be similar to flange  168  as discussed with respect to  FIGS. 7 and 8 . Flange  502  can be formed of the same materials discussed with respect to flange  168  of  FIGS. 7 and 8 . Flange  502  is preferably formed of an elastomeric material, which contracts or is folded back, such that the flange has a radial extent or profile small enough to fit within guide catheter  104 . Guide catheter  104  can be advanced to be near a target site, with flange  502  folded within guide catheter  104 . Inner shaft  66  can be advanced forward relative to guide catheter  104 , thereby deploying flange  502  to an expanded state having an increased radial extent or profile. Inner shaft  66  is preferably fixedly attached to flange  502 . As inner shaft cutting, tip  72  is advanced into the myocardium, flange  502  can serve to limit the extent of travel into the heart wall. After use, flange  502  can be retracted into guide catheter  104 , reducing the radial extent of flange  502 , and guide catheter  502  can be used further or retracted from the body. 
   Referring now to  FIG. 35 , a PMR device  520  is illustrated, advanced distally from guide catheter  104 . PMR device  520  includes inner shaft or therapeutic catheter  112  terminating in cutting tip  114 , discussed previously with respect to  FIGS. 3 and 4 . PMR device  520  includes a bulbous tip or hood  530  having an outer wall  522  and a distal region  526  terminating in a distal orifice  524 . Outer wall  522  can be formed of the same materials as outer wall  102  discussed with respect to  FIGS. 3 and 4 . Bulbous tip  530  can be fixedly attached to inner shaft  112  through flange  110  and at a bulbous tip proximal region  528 . Bulbous tip  530  is illustrated as having been distally extended from guide catheter  104 . 
   In use, cutting tip  114  can penetrate into the myocardium, with the depth of penetration limited by bulbous tip distal region  526  expanding upon contact with the endocardium. In operation, outer wall  522  can operate much the same as outer wall  102  illustrated in  FIG. 4 , expanding upon contact with the heart chamber wall. After use, bulbous tip  530  can be retracted into guide catheter  104 . In one embodiment, PMR device  520  has a shorter tube enclosing the inner shaft distal region relative to that of PMR device  100 . In one embodiment, PMR device  530  has inner shaft  112  directly disposed within guide catheter  104  for a majority of the length of inner shaft  112 . 
   Referring now to  FIG. 36 , a PMR device  540  is illustrated disposed within guide catheter  104 . PMR device  540  includes an inner shaft  542  terminating in a distal therapeutic and/or cutting tip  544  having expandable coil  204  secured to inner shaft  542  at a fixation location  543  located proximal of a cutting tip  544 . Coil  204  was discussed previously with respect to  FIGS. 13 and 14 . Inner shaft  542  can be formed of similar materials as inner shaft  112  discussed with respect to  FIG. 3 .  FIG. 36  illustrates coil  204  constrained within guide catheter  104 . 
   In use, guide catheter  204  can be advanced to near a target site, with PMR device coil  204  constrained within guide catheter  104 . Inner shaft  542  can be distally advanced, or guide catheter  103  proximally retracted, freeing coil  204 , allowing the coil to expand radially, as illustrated and discussed with respect to  FIGS. 13 and 14 . Coil  204  can act to limit the penetration of cutting tip  544  into the myocardium. After penetration into the myocardium, coil  204  can be retracted into the guide catheter. In some methods, inner shaft  542  is rotated to aid in bringing coil  204  within guide catheter  204 . 
   Numerous advantages of the invention covered by this document have been set forth in the foregoing description. It will be understood, however, that this disclosure is, in many respects, only illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of parts without exceeding the scope of the invention. The invention&#39;s scope is, of course, defined in the language in which the appended claims are expressed.

Technology Category: 1