Abstract:
Apparatus is disclosed for providing access to a functioning vascular system of a patient, the apparatus comprising: a main body having sidewalls defining an interior region and an exterior region, a bottom end and a top end; a base being formed at the bottom end of the main body, securing means being configured on the base so as to allow attachment and formation of a seal between the base and the functioning vascular system of the patient, and the base being configurable to provide a passageway from the interior region of the main body to the functioning vascular system of the patient; and a cover being formed at the top end of the main body, wherein the cover provides a barrier between the interior region and the exterior region at the top end of the main body.

Description:
REFERENCE TO THE PENDING PRIOR APPLICATIONS  
       [0001]    This patent application claims benefit of pending prior U.S. Provisional Patent Application Serial No. 60/243,869, filed Oct. 27, 2000 by Richard B. Streeter et al. for INTRACARDIOVASCULAR ACCESS (ICVA™) SYSTEM, which patent application is hereby incorporated herein by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention relates to medical devices and procedures in general, and more particularly to medical devices and procedures relating to the cardiovascular system.  
         BACKGROUND OF THE INVENTION  
         [0003]    In standard surgical practice, access to cardiac valves and internal cardiac structures is achieved with the use of cardiopulmonary bypass cardiac arrest and incision into the arrested heart or aorta. Using currently available technology, all cardiac valvular operations require such an approach.  
           [0004]    It is well-known that cardiopulmonary bypass and cardiac arrest are associated with significant morbidity and mortality. Recognition of the damaging effects of cardiopulmonary bypass has been the impetus for important advances in beating heart coronary artery bypass grafting. To date, however, it is believed that there are no clinically applicable techniques to perform cardiac valve surgery without using a heart-lung machine. Therefore, cardiac valve surgery currently requires a major operation that includes all of the complications attributable to cardiopulmonary bypass.  
           [0005]    In prior U.S. Provisional Patent Applications Serial Nos. 60/117,599, filed on Jan. 27, 1999, 60/152,135, filed on Aug. 25, 1999, 60/161,934, filed on Oct. 28, 1999, 60/215,542, filed on Jun. 30, 2000, and 60/230,756, filed on Sep. 7, 2000, and in pending PCT Patent Application No. PCT/US00/02126, filed on Jan. 27, 2000, which patent applications are hereby incorporated herein by reference, there are disclosed various devices and procedures to facilitate cardiac valve surgery on a beating heart. An important part of any such system is a safe technique for establishing direct intracardiovascular access to the heart, cardiac valves, and the so-called great vessels. Such access must allow the safe introduction of instruments into the cardiovascular system, prevent entry of air into the cardiovascular system, and prevent excessive bleeding. In this respect it should be appreciated that it is generally essential to avoid the introduction of air into the vascular system of the patient, since this could result in serious complications, or even death, for the patient. Another important part of the invention is to enable the simplified opening and closure of incisions into the cardiovascular system.  
         SUMMARY OF THE INVENTION  
         [0006]    In accordance with the present invention, there is provided a system which is adapted to facilitate safe intravascular access to any cardiac or vascular structure. The system is attached to the cardiovascular structure, using suture or sutureless fixation. Instruments may then be introduced into the system. The system is then partially or completely filled with saline, carbon dioxide, or other substance so as to provide an air-free environment, while also purging air from the previously inserted devices. The cardiovascular structure is then opened with a scalpel or other cutting instrument which, if desired, may be integral to the system. Valves on the system permit controlled passage of instruments into the cardiovascular system without excessive back bleeding. At the completion of the procedure, the system is removed, in whole or in part, and hemostasis is achieved by a means that may include suturing or stapling. Hemostasis may also occur during, or prior to, removal of the system.  
           [0007]    The system is not necessarily a stand alone device. The system&#39;s features and function can be incorporated into a surgical instrument, for use in vascular surgical procedures.  
           [0008]    The system has a specific advantage over cannullae in that large objects or devices may be passed through the system&#39;s large opening and into the patient&#39;s vascular system. Typically, cannullae only allow access for relatively long, narrow instruments.  
           [0009]    By way of further example but not limitation, other specific “beating-heart” applications of the invention can include:  
                                                       Access Site   Structure(s)   Purpose                           Right Atrium   Tricuspid Valve   Repair,                   Replace               Pulmonary Valve   Repair,                   Replace           Left Ventricle   Chordae Tendenae   Repair               Septum   Repair               Aortic Valve   Repair,                   Replace               Mitral Valve   Repair,                   Replace               Implanted Pumps   Repair,                   Clot                   Removal               Implanted Pacemaker   Removal,               Leads   Exchange,                   Functional                   Testing           Right Ventricle   Tricuspid and   Repair,               Pulmonic Valves   Replace               Septum   Repair               Implanted Pumps   Repair,                   Clot                   Removal               Implanted Pacemaker   Removal,               Leads   Exchange,                   Functional                   Testing                      
 
           [0010]    While the system may be used for a wide range of applications, several specific applications are anticipated.  
           [0011]    For example, it is anticipated that the system will be affixed to the left atrium of the heart, and/or to the pulmonary veins, in order to allow direct access to the mitral valve. Instruments can then be introduced through the system to perform mitral valve repair or replacement, with or without the use of cardiopulmonary bypass.  
           [0012]    Furthermore, in beating heart aortic valve surgery, the system could be affixed to the aorta or to the left atrium. Instruments and an aortic prosthesis could then be introduced to the vascular system of the patient through the system. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    These and other objects and features of the present invention will be more fully disclosed or rendered obvious by the following detailed description of the preferred embodiments of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts and further wherein:  
         [0014]    [0014]FIG. 1 is a perspective view of a system formed in accordance with the present invention;  
         [0015]    [0015]FIG. 2 is a front view of the system shown in FIG. 1;  
         [0016]    [0016]FIG. 3 is a side view of the system shown in FIG. 1;  
         [0017]    [0017]FIG. 4 is a bottom view of the system shown in FIG. 1;  
         [0018]    FIGS.  5 A- 5 C illustrate the formation and closure of a pair of pursestring stitches which may be used in conjunction with the present invention;  
         [0019]    [0019]FIG. 6 is a bottom view of an alternative form of the invention;  
         [0020]    [0020]FIG. 7 is a bottom view of another alternative form of the invention;  
         [0021]    [0021]FIG. 8 is a bottom view of still another alternative form of the invention;  
         [0022]    [0022]FIG. 9 is a bottom view of yet another alternative form of the invention;  
         [0023]    [0023]FIG. 10 is a side view of another alternative form of the invention;  
         [0024]    [0024]FIG. 11 is a front view of still another alternative form of the invention;  
         [0025]    [0025]FIGS. 12 and 13 illustrate the formation and closure of alternative pursestring stitches which may be used in conjunction with the present invention;  
         [0026]    [0026]FIG. 14 is a schematic bottom view showing an alternative method for closing an incision at the conclusion of the procedure;  
         [0027]    [0027]FIG. 15 is a schematic view of yet another form of the present invention;  
         [0028]    FIGS.  16 - 18  are views of still another form of the present invention;  
         [0029]    [0029]FIG. 19 is a front view of the present invention, showing staples attaching the system to tissue; and  
         [0030]    [0030]FIGS. 20 and 21 are views of an alternative device and method to close an incision at the conclusion of the procedure. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0031]    Looking now at FIGS.  1 - 4 , there is shown a new system  5  which may be used to gain safe and easy air free access to the functioning (or operating) vascular system of a patient. System  5  generally comprises a main body  10 , a base  15  and a cover  20 .  
         [0032]    Main body  10  is a hollow structure and comprises a tapered wall  25  having a bottom end  30  and a top end  35 . Tapered wall  25  is preferably formed out of a flexible, clear plastic material, e.g., urethane. The bottom end  30  of tapered wall  25  is connected to base  15  as shown, e.g., by being formed integral with base  15 . The top end  35  of tapered wall  25  includes a mount  40  whereby cover  20  may be removably mounted to main body  10 , e.g., with thumb screws  45 . Mount  40  is preferably formed out a substantially rigid, clear plastic material, e.g., polycarbonate.  
         [0033]    Base  15  is a hollow structure which preferably includes a stitching cuff  50  extending around the perimeter of base  15 . Stitching cuff  50  permits the system  5  to be secured to a cardiovascular structure, e.g., to the wall of the left atrium of the heart. Base  15  is preferably formed out of a flexible, clear plastic material, e.g., urethane. Stitching cuff  50  is preferably formed out of a clinically acceptable fabric, e.g., Dacron.  
         [0034]    Cover  20  is preferably adapted to be removably attached to mount  40  of main body  10 . Cover  20  preferably includes several (e.g., three) ports  55  for gaining access to the interior of the system. One of these ports, e.g., port  55 A, may comprise the base for a Luer lock fitting or, if desired, may comprise the entire Luer lock fitting. Others of the ports, e.g., ports  55 B and  55 C, may comprise passageways for instruments. Preferably such instrument ports (e.g., ports  55 B and  55 C) include penetrable seals  60  of the sort well known in the art for minimizing the flow of fluid through the instrument ports, both when instruments are being passed through the instrument ports and when instruments are not being passed through the instrument ports. Cover  20  is preferably formed out of a substantially rigid, clear plastic material, e.g., polycarbonate.  
         [0035]    System  5  may be used to gain safe and easy access to the cardiovascular system of a patient.  
         [0036]    By way of example but not limitation, system  5  may be used to gain safe and easy access to the left atrium of a beating heart, whereby to perform a mitral valve replacement or repair while the heart is beating.  
         [0037]    In such a procedure, the surgeon first chooses an access site on the surface of the heart, adjacent to the patient&#39;s left atrium.  
         [0038]    Next, a special running stitch may be pre-placed at the access site. This running stitch is preferably a modified pursestring stitch formed out of two separate pursestring stitches, as shown in FIGS. 5A and 5B which, when subsequently pulled tight, will gather together tissue, as shown in FIG. 5C. The running stitch is placed about the perimeter of the site where the incision will be made, such that, at the conclusion of the procedure, the free ends of the pursestring stitches may be pulled, whereby to close the incision, as will hereinafter be discussed in further detail.  
         [0039]    Then the prosthesis (i.e., the artificial valve) is placed in the interior of the system&#39;s main body  10 , and cover  20  is secured to the top of main body  10  (e.g., with thumb screws  45 ).  
         [0040]    At this point, system  5  is secured to the wall of the heart so that the system&#39;s base  15  encircles the running stitch at the incision site. System  5  may be secured to the wall of the left atrium by suturing its stitching cuff  50  to the wall of the beating heart so as to form a substantially fluidtight seal, or a more complex stapling device may be used to secure system  5  to the wall of the left atrium.  
         [0041]    Next, carbon dioxide may be introduced into blood lock  5  to displace air from the system. Then a saline source (not shown) is connected to the Luer connector of the system, and the lock is filled with saline.  
         [0042]    At this point the system is gently shaken, while attached to the wall of the heart, so as to free up any gas bubbles which may be trapped about the prosthesis. In this respect it will be appreciated that, inasmuch as the interior of system  5  was purged with carbon dioxide prior to being filled with saline, any gas bubbles which might still remain in the interior of the system even after such shaking will be harmless carbon dioxide bubbles, rather than dangerous air bubbles. In a preferred embodiment, a manifold device integral to the system, or temporarily attached thereto, purges air from the system prior to cutting an incision. This manifold device has hoses connected to it from a suction source, a CO 2  source and a saline source. The manifold also has an “OFF” position. To purge the blood access system, the surgeon will first apply suction to the system to evacuate most of the air; then fill the system with CO 2  to displace any remaining oxygen; and finally fill the system with saline. Any remaining bubbles will mostly be harmless CO 2 . Alternatively, this device could be a separate manifold tool used to purge any device that might inject air to the circulatory system and be inserted to the blood access system through one of the access seals  60 .  
         [0043]    A scalpel is then inserted into an instrument port on the system, and an incision is made through the left atrium wall from the inside of the system. This incision is made within the perimeter of the aforementioned running stitch so as to avoid cutting the suture.  
         [0044]    Then base  15  of the system, which is flexible and stitched to the wall of the heart, is pulled apart so as to cause the incision to open wide. In this way, a 2 inch incision will yield an approximately 1 inch diameter hole through the wall of the left atrium. However, due to the column of fluid (i.e., saline) contained in system  5 , as well as the presence of seals  60 , effectively no bleeding will occur.  
         [0045]    The prosthetic valve, which was previously placed within the interior of the system, may now be passed through the wall of the left atrium and into position within the heart. Instruments may then be safely and easily passed through the system so as to secure the prosthetic valve in position within the heart.  
         [0046]    Once the prosthesis is secured in position within the heart, the instruments are removed from the system, and then the running stitch is pulled tight so as to close the incision in the wall of the left atrium.  
         [0047]    Finally, the system is removed from the heart, e.g., by unstitching stitching cuff  50  from the wall of the heart, and then the incision is permanently closed with additional suture or staples while being held closed with the running stitch.  
         [0048]    Looking next at FIGS. 6 and 7, several alternative embodiments are illustrated for attaching system  5  to a cardiovascular structure.  
         [0049]    More particularly, in FIG. 6 there is shown a releasable vacuum lock  65  which is adapted to securely attach system  5  to the wall of the heart with a fluidtight seal. Releasable vacuum lock  65  comprises a groove  70  formed in the floor  72  of base  15  and a vacuum fitting  75  communicating therewith, such that when base  15  is positioned against the outer wall of the heart, and a vacuum source is connected to vacuum fitting  75 , system  5  may be releasably attached to the wall of the heart through suction.  
         [0050]    In another alternative embodiment, and looking now at FIG. 7, the floor  72  of base  15  is adapted to be glued to the outside wall of the heart, whereby to secure the base of system  5  to the wall of the heart. At the conclusion of the cardiac procedure, in order to remove system  5  from the wall of the heart, the system&#39;s tapered wall  25  is cut away from base  15 . Base  15  may then be left permanently attached to the outside wall of the heart. Any system remnant left attached to the outside of the heart at the conclusion of the procedure should be a soft, flexible material that will not constrain the contractibility of the heart during distole or systole. Additionally, any remnant left on the heart may be over-sewn so as to assure an air-tight seal.  
         [0051]    Looking next at FIG. 8, a blade guide  80  is provided at base  15  of system  5 . Blade guide  80  is adapted to guide a cutting tool (not shown) during an incision through the wall of the heart. To this end, blade guide  80  includes a floor  85  which is resistant to penetration by a cutting blade. This floor  85  may or may not be formed integral with the floor  72  of base  15 . Floor  85  includes an opening  90  therein. Opening  90  is initially in the form of a narrow slit so as to act as a guide for a cutting tool when that cutting tool is making an incision through the wall of the heart. This guide may relate to both the perimeter of the incision and the depth of the incision. Floor opening  90  is also adapted to allow larger objects, including prosthetic devices and surgical instruments, to pass through blade guide  80  and then through the wall of the heart. To this end, a pair of tabs  95  are provided for pulling the sides of base  15  outward, whereby to enlarge opening  90  and allow larger objects to pass by the blade guide. In this respect it will be appreciated that inasmuch as the system&#39;s base  15  is secured to the wall of the heart when tabs  95  are pulled apart, enlargement of opening  90  will be accompanied by enlargement of the incision as well.  
         [0052]    Looking next at FIG. 9, in another alternative embodiment, system  5  has a narrow, flexible base  15  having opposing ends  100 ,  105  and containing blade guide  80 . Base  15  is attached to the wall of the heart as described above using suture cuff  50 , releasable vacuum lock  65 , or glued floor  72  (this latter configuration is depicted in FIG. 9). An incision is made through blade guide  80  into the wall of the heart. Ends  100 ,  105  are then pushed toward one another so as to expand base  15  of system  5 . Expansion of base  15 , which is attached to the wall of the heart, increases the openings of both blade guide opening  90  and the incision. A prosthetic device and other objects may then be introduced through the increased opening in blade guide opening  90  and the increased opening of the incision. Blade guide opening  90  and the incision in the wall of the heart may thereafter be closed by simply relaxing the pressure on opening base ends  100 ,  105 . In the preferred embodiment, instruments may be passed through, and manipulated in, the “closed” position of the incision.  
         [0053]    In another preferred embodiment, and looking now at FIG. 10, blood lock  5  is provided with a relatively tall main body  10 . System  5  is partially filled with fluid and the level  110  of fluid rises and falls with each beat of the heart. This configuration is possible due to the relatively low pressure, i.e., about 5-10 mm Hg, inside the atriums of the heart and the pulmonary veins. This configuration can be advantageous in that a reliable fluid lock is maintained even if cover  20  should be removed intermediate the procedure, e.g., to receive another prosthetic device and/or oversized instruments.  
         [0054]    As noted above, blood lock  5  contains seals  60  for selectively closing off its instrument ports  55 B and  55 C. Examples of such seals are cruciform seals, conical seals and other simple seals. Seals  60  may also include more complex structures such as the articulating seals  115  shown in FIG. 11, whereby to allow greater manipulation of various instruments through the seals.  
         [0055]    As also noted above, the incision in the wall of the heart is closed off at the conclusion of the intravascular procedure. In one preferred form of the invention, the running stitch of FIGS.  5 A- 5 C is used. Several additional constructions are described below for closing off the incision in the heart wall.  
         [0056]    In one preferred construction, and looking now at FIGS. 12 and 13, the incision  120  is preliminarily closed after the intravascular procedure is completed using multiple pursestring stitches  125 A,  125 B and  125 C. Pursestring stitches  125 A,  125 B and  125 C are pre-positioned as shown in FIG. 12. Then the bodies of the pursestring stitches  125 A and  125 B are pulled so as to open a place for incision  120  (FIG. 13). After attachment of system  5  to the wall of the heart, incision  120  is made within the perimeter of the extended pursestring stitches  125 A and  125 B, and within the perimeter of pursestring stitch  125 C. At the end of the procedure, each pair of pursestring ends are pulled so as to draw each pursestring stitch tight and thereby close incision  120  along its length without causing bunching in the wall of the heart. Then system  5  is removed as described above.  
         [0057]    In another preferred embodiment, the incision is closed off by suturing prior to removal of system  5  from the wall of the heart, as illustrated in FIG. 14. In this case, instead of pre-positioning a closing suture, such as a running stitch, in the region where the system will be placed, system  5  is simply attached to the wall of the heart. At the conclusion of the intravascular procedure, incision  120  is sutured closed by simply placing sutures  127  through, or outside of, system  5 . After incision  120  is sutured closed, all or part of system  5  is removed from the wall of the heart. Additional suturing to close incision  120  may also be preformed after the removal of system  5 .  
         [0058]    In another preferred embodiment, cover  20  is formed integral with main body  10  so as to form a closed container  130 , shown in FIG. 15. Base  15  is open so as to allow introduction of a prosthesis to the interior of the system prior to the attachment of the system to the wall of the heart. Closed container  130  includes one or more ports  40  to introduce instruments during the intravascular procedure. After attachment of base  15  to the wall of the heart, ports  40  are the only exposure to the outside environment. This configuration may provide a greater integrity of system  5  as cover  20  cannot be removed during the procedure, however, the prosthesis cannot be changed during the intravascular procedure due to the permanent closure of the top end of the system.  
         [0059]    In addition to the foregoing, the container  130  shown in FIG. 15 can be formed with a closed bottom wall. In this configuration, the prosthesis is pre-loaded into container  130  at the time of manufacture; thereafter, during use, after the container  130  has been filled with saline, a sharp cutting instrument is introduced through a port  40  and used to simultaneously cut through the system&#39;s closed bottom wall and the wall of the heart. Furthermore, if desired, container  130  could be pre-filled with saline at the time of manufacture, and its closed bottom wall could be pre-coated with an adhesive at the time of manufacture, with the adhesive being covered by a peel-off tab until use.  
         [0060]    Now looking at FIGS.  16 - 18 , the system  5  may also be formed as part of a tool  135 . Tool  135  includes hooks  140  to secure tool  135  to the wall of the heart. An access port  145  is provided for insertion of a scalpel, and a port  150  is provided for connection to a purge line. Tool  135  is used by simultaneously plunging and turning hooks  140  into the wall of the heart so as to secure tool  135  to the heart (FIG. 18).  
         [0061]    Now looking at FIG. 19, a system  5  is shown with staples  155  delivered to its stitching cuff  50  so as to secure the system to the wall of the heart. Staples  155  may be delivered by a complex stapling device.  
         [0062]    [0062]FIGS. 20 and 21 detail an alternative device and method to close the surgical incision  120 . Without limiting the scope of this invention, the preferred embodiment of this device and method is to directly close stitching cuff  50  with suture  156 , below the base  15  and as close to the surgical incision  120  as possible, which in turn holds incision  120  closed during the healing process. The closed stitching cuff  50  may then either be cut away or detached from the base  15  above cuff closing suture  156  but below the stitching cuff interface  157 . This interface  157  is created during the manufacturing process and may be any one of a number of fixation methods such as sewing, stapling, insert molding or mechanical crimping. This interface may also be the position where the implanted stitching cuff  50  is removed from the base  15 . FIG. 21 shows the implanted stitching cuff  50 , closed with closing suture  156 . It is also envisioned that closing suture  156  may be one of many closing mechanisms such as wire, staples or adhesives. Additionally, in case of an emergency, the surgeon may quickly close the open incision  120  by placing a large hemostat across the stitching cuff along the same path of closing suture  156  is shown in FIG. 21. Additionally, as described earlier, suture cuff  50  may be attached to the surgical site via sutures  158  or hooks  140  or staples  155  or adhesive or other appropriate attaching means.