Patent Publication Number: US-9415148-B2

Title: Method of delivering a transseptal cannula to a heart

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a divisional of U.S. application Ser. No. 13/888,641, filed May 7, 2013 (now U.S. Pat. No. 9,028,393) which is a divisional of U.S. application Ser. No. 12/720,012, filed Mar. 9, 2010 (now U.S. Pat. No. 8,460,168) which claims the benefit of U.S. Provisional Patent Application Ser. No. 61/163,926, filed on Mar. 27, 2009, the disclosures of which are incorporated by reference herein. 
    
    
     BACKGROUND 
     Circulatory assist devices were developed over a decade ago and provide assistance to a diseased heart by way of a mechanical pump. In this way, the circulation of blood through the vascular network is aided despite the presence of diseased tissue. Traditionally, these circulatory assist devices included an implantable pump, a controller (internal or external), and inflow and outflow tubes connecting the pump to the vascular network. The FDA has approved circulatory assist devices to partially relieve the symptoms of breathlessness and fatigue that are associated with severe heart failure and can drastically improve a patient&#39;s quality of life. 
     The surgical process associated with the circulatory assist device is highly invasive. At the very least, the procedure involves a thoracotomy, i.e., the opening of the thoracic cavity between successive ribs to expose the internal organs. More typical is cardiac surgery, generally known as open-heart surgery, where the sternum is cut and split to expose the internal organs. Once the thoracic cavity is accessed, the physician must enter the pleural space and puncture both the pericardium and the myocardial wall. There are great risks and an extensive recovery time associated with the implantation surgery. As such, the patients with severe symptoms are not healthy enough for the surgical procedure. 
     A transseptal cannula is described in U.S. patent application Ser. No. 12/256,911, the disclosure of which is incorporated herein by reference in its entirety. The transseptal cannula described therein provides greater accessibility to the circulatory assist device by minimizing the invasiveness of the implantation surgery for those patients who would gain the most benefit while awaiting a heart transplant. 
     There continues to be a need to implement additional features that would facilitate the delivery of the transseptal cannula and/or that would allow the physician to maintain control over the transseptal cannula device during the surgical procedure. 
     SUMMARY 
     In one embodiment, a coaxial balloon catheter is provided and includes a tube body, a coaxial hub, and a balloon. The tube body includes an inner member and outer member surrounding the inner member and thereby creating an inflation channel between the inner and outer members. The hub is coupled in a coaxial manner to the proximal portion of the tube body and includes a fluid space in fluid communication with the inflation channel. The coaxial hub has a low profile so that a surgical device can be loaded over the coaxial hub. The balloon is coupled to a distal portion of the tube body and a distal portion of the inner member extends through the balloon thereby creating an annular cavity between a wall of the balloon and the inner member. 
     A transseptal cannula assembly is also provided and includes a flexible cannula body, a left atrial anchor, and a right atrial anchor. The flexible cannula body includes distal and proximal ends with a lumen extending therebetween. The left atrial anchor is coupled to the distal end of the flexible cannula body and is configured to be deployed from a contracted state to an expanded state to engage at least one side of heart tissue is the expanded state. The right atrial anchor is attachable to the left atrial anchor in vivo and is configured to be deployed from a contracted state to an expanded state to engage an opposing side of the heart tissue in expanded state. The transseptal cannula may be used in combination with a left anchor delivery system including a sheath and a proximal hub. The transseptal cannula assembly may also be used in combination with a right anchor delivery system. The right anchor delivery system comprises a right anchor delivery apparatus configured to engage the left atrial anchor and couple the right atrial anchor to the left atrial anchor. A right anchor sheath includes a proximal hub and a sheath body configured to receive the right anchor delivery apparatus and move relative thereto for deploying the right atrial anchor into the expanded state. 
     Methods of delivering a transseptal cannula assembly to a heart tissue are also disclosed. 
     Various other details, embodiments and features are disclosed herein and are detailed below in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a diagrammatic view of an exemplary method of implanting the transseptal cannula assembly in a human heart, shown in cross-section. 
         FIG. 2A  is a disassembled, side elevational view of a delivery apparatus and transseptal cannula assembly. 
         FIG. 2B  is an assembled, side elevational view of the delivery apparatus with the transseptal cannula assembly. 
         FIG. 3  is a side elevational view of a coaxial balloon catheter, shown in cross-section. 
         FIG. 3A  is a cross-sectional view of a coaxial hub of the coaxial balloon catheter, taken along line  3 A- 3 A of  FIG. 3 . 
         FIGS. 4A-4E  are side elevational views in partial cross section of an exemplary method of deploying a left atrial anchor of the transseptal cannula assembly. 
         FIG. 5A  is a disassembled, side elevational view of a right atrial anchor delivery system with the transseptal cannula and the coaxial balloon catheter. 
         FIG. 5B  is an assembled, side elevational view of the right atrial anchor delivery system with the transseptal cannula and coaxial balloon catheter. 
         FIG. 6A  is a perspective view of an exemplary method of assembling the right anchor delivery system and back-loading the right anchor delivery system over the transseptal cannula assembly. 
         FIG. 6B  is a side elevation view in partial cross-section of the exemplary method of back-loading the right anchor delivery system over the transseptal cannula assembly. 
         FIG. 6C  is a perspective view of an exemplary method of advancing the right anchor delivery system over the transseptal cannula assembly. 
         FIGS. 6D-6E  are side elevation views in cross section of an exemplary method of deploying the right atrial anchor of the transseptal cannula assembly. 
         FIG. 6F  is a perspective view of the right atrial anchor. 
         FIGS. 6G-6J  are side elevational views in cross section of the exemplary method of completing the implanting of the right atrial anchor of the transseptal cannula assembly. 
         FIG. 6K  is a diagrammatic view of an illustrative circulatory assist system positioned in the human heart, shown in cross-section. 
     
    
    
     DETAILED DESCRIPTION 
     Implanting a circulatory assist device according to one embodiment can begin with a percutaneous transseptal crossing procedure.  FIG. 1  illustrates a portion of this procedure, where the physician gains access to the heart  10  of the patient  12  from a superior incision site  14 . A suitable location for the superior incision site  14  can be substantially near a superior superficial vein, such as the right or left subclavian veins  15 ,  16 ; the right or left jugular veins  17 ,  18 ; or the junction between a jugular vein  17 ,  18  and the corresponding adjoining subclavian vein  15 ,  16 . There are several methods by which the physician can gain access to the heart  10 . One example not specifically illustrated here, but disclosed in U.S. patent application Ser. No. 12/256,911, the disclosure of which is incorporated herein by reference in its entirety, includes creating a femoral vein access site and directing an anchoring guide-element from the femoral vein access site to the patient&#39;s heart  10  and through a heart tissue. A distal portion of the anchoring guide-element is secured to the heart tissue while a proximal portion of the anchoring guide-element is transferred from the femoral vein access site to the superior superficial vein site via a capture device, such as a conventional snare device. Another example not specifically illustrated but also disclosed in U.S. patent application Ser. No. 12/256,911 includes directing a steerable guidewire from the superior superficial vein site directly to the patient&#39;s heart  10 . The steerable guidewire then crosses the heart tissue. 
     Referring still to  FIG. 1 , once the guidewire  19  (or anchoring guide-element) traverses the heart tissue, such as the intra-atrial septum  20 , and enters the left atrium  21 , a transseptal cannula  22  with a left anchor delivery system  25  is back-loaded over a proximal end of the guidewire  19 . The transseptal cannula  22  is then directed through the right subclavian vein  15 , the superior vena cava  23 , and into the right atrium  24 . 
       FIG. 2A  illustrates the details of the left anchor delivery system, which includes a delivery apparatus  26  and a coaxial balloon catheter  28  for aiding in implanting of the transseptal cannula  22 . The delivery apparatus  26  has a proximal hub  32  and a sheath that is configured to receive and move relative to the flexible cannula body. The sheath, as illustrated, includes a distal sleeve  36  that is connected to the proximal hub  32  by at least one connector member  34 . The proximal hub  32  provides visual and tactile feedback with respect to the deployment of a left atrial anchor  38  (described in detail below) of the transseptal cannula  22 . The proximal hub  32  can be molded as a single polymeric material that is noncompliant, i.e., does not change shape during the physician&#39;s use. The proximal hub  32  of the delivery apparatus  26  may include a docking portion  40  for receiving a proximal end of the coaxial balloon catheter  28 . The docking portion  40  sets a relative position between the coaxial balloon catheter  28  and the delivery apparatus  26  to aid in maintaining the left atrial anchor  38  within the distal sleeve  36  during the implanting procedure. The docking portion  40  may also aid in minimizing blood loss from between the guidewire  19  and the coaxial balloon catheter  28 . 
     The at least one connector member  34  of the delivery apparatus  26  that couples the distal sleeve  36  to the proximal hub  32  can be constructed from a rigid polymeric material or a metallic wire. While only one connector member  34  is shown, it would be understood that additional connector members  34  can be used. The connector members  34  allow the physician to maintain direct control of the transseptal cannula  22  while manipulating the delivery apparatus  26 . 
     The distal sleeve  36  secures the left atrial anchor  38  during the delivery of the transseptal cannula  22  to the intra-atrial septum  20  ( FIG. 1 ). The distal sleeve  36  can be constructed as single or multiple polymeric layers having lengths sufficient to cover the left atrial anchor  38 . 
     In another embodiment not specifically illustrated, the sheath of the delivery apparatus extends from the proximal hub and for the length of the transseptal cannula to secure the left atrial anchor  38  during the delivery of the transseptal cannula  22 . This sheath embodiment of the delivery apparatus is directed over the transseptal cannula  22  and moves relative thereto for deploying the left atrial anchor  38 . 
       FIG. 2A  illustrates the details of the transseptal cannula  22 . The transseptal cannula  22  is designed such that left and right atrial anchors are implanted and deployed separately. This particular arrangement of the transseptal cannula is able to accommodate greater patient-to-patient variation in intra-atrial septal wall thicknesses and anatomies. The transseptal cannula includes a flexible cannula body  42  and the distally located left atrial anchor  38 . The flexible cannula body  42  can be constructed of a polymeric material, such as thermoplastic or thermoset. A thin-film metallic coating may be applied to the polymeric material to inhibit the formation of a thrombosis. Other coatings can also be applied, such as with polyethylene terephthalate glycol (PETG) for lubricating the flexible cannula body  42 . The flexible cannula body  42  may include both a pliable cannula portion  46  and a reinforced cannula portion  48 . The pliable cannula portion  46  allows the flexible cannula body  42  to be secured to a circulatory assist device. The reinforced cannula portion  48  provides structural stability, increases the ease of manipulating the transseptal cannula  22  through the vascular network, and decreases the likelihood of the flexible cannula body  42  kinking within the vascular network. The reinforced cannula portion  48  may be constructed by single and/or multi-layer encapsulation of a wire braid or coil; the pliable cannula portion  46  may or may not include the wire braid or coil. 
     The left atrial anchor  38  includes a tip  50  and at least two opposed struts  51  coupled to the tip  50 . When implanted, the tip  50  will create a shunt through the intra-atrial septum  20  ( FIG. 1 ). The overall length of the tip  50  can vary according to a particular patient&#39;s anatomical needs. Accordingly, in some embodiments, the distal end of the tip  50  could extend as far as 1 cm into the left atrium  21  ( FIG. 1 ); however, in other embodiments, the length of the tip  50  would be flush with the intra-atrial septum  20  ( FIG. 1 ). The tip  50  can be constructed from a polished metallic, such as titanium (Ti), or from a polymeric material with tungsten (W) embedded for fluoroscopic localization. 
     The left atrial anchor  38  can, in some embodiments, include a cuff  52  (shown in phantom) to promote tissue in-growth and to further secure the transseptal cannula  22  to the heart tissue. The cuff may be any porous polymeric structure that provides an area for tissue in-growth, and increases the structural stability and sealing capacity as compared to the tip  50  alone. Suitable materials for the cuff  52  may include expanded polytetrafluoroethylene (ePTFE) and DACRON. The cuff  52  can generally be in at least one of two locations: an inner cuff  52  at the junction between the tip  50  and the flexible cannula body  42 ; or an outer cuff (not shown) surrounding a joint between the struts  51  and the tip  50 . The outer cuff can provide the added benefit of minimizing a galvanic response between the tip  50  and the struts  51 . 
     Referring still to  FIG. 2A , but also to the assembled view in  FIG. 2B , the delivery apparatus  26  and the transseptal cannula  22  are shown to coaxially surround the coaxial balloon catheter  28 . The coaxial balloon catheter  28  has a coaxial hub  56 , a strain relief  58 , a tube body  60 , and a balloon  62 . 
       FIG. 3  illustrates the coaxial balloon catheter  28  with greater detail. The tube body  60  has an inner member  64 , an outer member  66 , and an inflation channel  68  therebetween. The inner and outer members  64 ,  66  can be tubular structures extending from the coaxial hub  56  to the balloon  62 . The inner and outer members  64 ,  66  of the tube body  60  may be formed by an extrusion process from a flexible polymeric material, such as PEBAX or polyurethane. The inflation channel  68  provides a liquid conduit for an inflation fluid, such as saline or a contrast medium, to travel between the coaxial hub  56  and the balloon  62 . 
     The proximal end of the inner member  64  is coupled to the coaxial hub  56  while the distal end of the inner member  64  extends through the balloon  62  and is coupled at the distal end of the balloon  62 . The inner member  64  includes a lumen  70  that is substantially similar in diameter to the diameter of the guidewire  19  ( FIG. 2A ). The inner member  64  can also include at least one distally located marker  69  constructed from a metallic material, such as gold (Au) or platinum (Pt) or from a polymeric material embedded with a dense powder, such as tungsten (W). The marker  69  aids the physician in positioning the transseptal cannula  22  in vivo and in a manner that is described in detail below. Though not shown, if two or more marker bands are used, then the more distal marker band can be used to position the left atrial anchor  38  ( FIG. 2A ) within the left atrium  21  ( FIG. 1 ) while the more proximal marker band can be used to position the right atrial anchor (discussed below) within the right atrium  24  ( FIG. 1 ). 
     The proximal end of the outer member  66  of the coaxial balloon catheter  28  is coupled to the coaxial hub  56  while the distal end of the outer member  66  is coupled to the proximal end of the balloon  62 . The hub-inner member bond  71  may be positioned proximal to the hub-outer member bond  72  to improve lumen inflation patency. A chemical bond (UV adhesive) or energy transfer process (thermal melting or RF) can be used to couple the inner and outer member  64 ,  66  to the coaxial hub  56 . 
       FIGS. 3 and 3A  illustrate the coaxial hub  56  of the coaxial balloon catheter  28 . The coaxial hub  56  is constructed to have a low profile, such as a cylindrical or other straight or continuous outer profile, that would allow other hollow or tubular surgical devices to be directed over the coaxial hub  56  without deflating and removing the balloon  62 . This is unlike a typical Y-shaped hub, for example, that would not allow such a function. The coaxial hub  56  has a hub-body  74 , a hub-cap  75 , a plurality of spokes  76 , and a grommet  78 . The hub-body  74  and hub-cap  75  form the main body of the coaxial hub  56 . The plurality of spokes  76  are integrally molded within the hub-body  74 , provide a positive stop for the grommet  78 , and define a fluid space  79  that is in fluidic communication with the inflation channel  68 . The plurality of spokes  76  can also provide a surface for coupling the inner member  64  to the coaxial hub  56 . The grommet  78  provides a fluid-tight seal for holding a desired liquid pressure within the balloon  62  while permitting a syringe needle, or other similar solid object, to puncture and pass to the fluid space  79 . The grommet  78  can be self-healing, i.e., maintains the fluid seal after the syringe needle has been removed. The hub-cap  75  can include a grommet retention feature  80  to prevent migration of the grommet  78  from the coaxial hub  56  after assembly. 
     The hub-body  74  and hub-cap  75  of the coaxial hub  56  can be molded from the same, or different, rigid materials that will resist compression. Suitable materials may include nylon or polycarbonate. The grommet  78  is formed by a molding process of an elastomeric material, such as polyurethane or silicone (Si). Once the grommet  78  is positioned within the hub-cap  75 , the hub-cap  75  and hub-body  74  are bonded using chemical bonding (UV adhesives) or an energy transfer process (thermal melting or RF). 
     The strain relief  58  can be bonded to the coaxial hub  56  by interference fit or by chemical bond. The strain relief  58  strengthens the connection between the rigid coaxial hub  56  and the more flexible tube body  60  and provides a transition that aids in kink resistance at this location. 
     Continuing with  FIG. 3 , the balloon  62  can be constructed from a compliant polymeric material (lower durometer) for easy inflation or from a noncompliant polymeric material (higher durometer) that will resist change with increases in fluidic pressure. Suitable compliant materials can include PEBAX or polyurethane while noncompliant materials can include nylon or polyethylene terephthalate (PET). The balloon material is shaped to a cylindrical shape by a thermoforming process and is then bonded to the inner and outer members  64 ,  66  by either an energy transfer process (thermal melting or RF) or a chemical bonding (UV adhesive). The walls of the balloon  62  and the inner member  64  create an annular cavity  86  in fluid communication with the inflation channel  68  of the tube body  60 . The fully inflated balloon  62  can withhold liquid pressures up to approximately 12 atm. The at least partially inflated balloon  62  will include a distal cone structure  82  that can facilitate the dilation of an opening through the intra-atrial septum  20  ( FIG. 1 ) in a manner described below. The proximal end  84  of the balloon  62  should include sufficient surface area for coupling the balloon  62  to the outer member  66  by an energy transfer process or chemical bonding. 
     To inflate the balloon  62 , the physician inserts a syringe needle of a syringe containing the inflation fluid through the grommet  78  of the coaxial hub  56  and into the fluid space  79 . The inflation fluid is transferred from the syringe to the fluid space  79 , the inflation channel  68 , and into the annular cavity  86  of the balloon  62  where it will increase the fluid pressure and cause the walls of the balloon  62  to expand. 
     With the details of the left anchor delivery system  25  ( FIG. 2A ) and the transseptal cannula  22  described with some detail, the method of implanting the transseptal cannula  22  with the left atrial anchor  38  can continue with reference to  FIGS. 4A-4F .  FIG. 4A  illustrates the delivery apparatus  26 , the transseptal cannula  22 , and the coaxial balloon catheter  28  coaxially loaded over the guidewire  19 . The balloon  62  is positioned within the lumen of the tip  50  such that the marker  69  is approximately aligned with the distal end of the tip  50 . Then, as the balloon  62  is inflated with the inflation fluid, the balloon  62  contacts the inner diameter of the tip  50 . This contact between the tip  50  and the balloon  62  allows the physician to advance the transseptal cannula  22  and the coaxial balloon catheter  28  as a unit over the guidewire  19 . 
     Also, as shown, the balloon  62  can be further inflated to contact the inner diameter of the distal sleeve  36  of the delivery apparatus  26 . This contact between the distal sleeve  36  and the balloon  62  would further allow the physician to advance the transseptal cannula  22 , the coaxial balloon catheter  28 , and the delivery apparatus  26  as a unit over the guidewire  19 . The relative positions of the coaxial balloon catheter  28  and the delivery apparatus  26  can further be aided by positioning the coaxial hub  56  of the coaxial balloon catheter  28  within the docking portion  40  of the delivery apparatus  26 . 
       FIG. 4B  illustrates the delivery apparatus  26 , the transseptal cannula  22 , and the coaxial balloon catheter  28  within the right atrium  24  and advanced to the intra-atrial septum  20 . 
     In  FIG. 4C , the delivery apparatus  26  with the coaxial balloon catheter  28  and the transseptal cannula  22  are shown advancing, as a unit, through the intra-atrial septum  20  and into the left atrium  21 . During the advancing, the distal cone structure  82  contacts and dilates the opening  87  through the intra-atrial septum  20  that was created previously by the guidewire  19 . In this way, the opening  87  is sufficiently dilated so that the distal sleeve  36  may also easily enter the left atrium  21 . 
       FIG. 4D  illustrates one method of deploying the struts  51  of the left atrial anchor  38  within the left atrium  21  from a contracted state (shown in phantom) to an expanded state (shown in solid). Struts  51  in the expanded state are transverse to a lengthwise central axis of the flexible cannula body  42  and will resist movement of the transseptal cannula  22  in at least one direction along the lengthwise central axis. The struts  51  can be machined from a tubular structure, formed from wire, or formed from a flat sheet stock, which may be any superelastic, shape-memory material, such as nickel titanium (NiTi) or MP35N. In some embodiments, the struts  51  remain bare; however, it is possible to include a porous polymeric structure, such as a coating of calcium phosphate (Ca 3 (PO 4 ) 2 ), collagen, or a porous polymeric fabric to promote tissue in-growth and further secure the tip  50  to the heart tissue. 
     Deploying the left atrial anchor  38  begins with the physician confirming that the tip  50  and the struts  51  are through the intra-atrial septum  20  and within the left atrium  21 . The confirmation can be accomplished by in vivo localization of the marker  69  with X-ray, real-time fluoroscopy, or intracardiac echocardiograph. After the confirmation, the balloon  62  is at least partially deflated to remove the contact between the distal sleeve  36  and the balloon  62  such that the distal sleeve  36  moves with respect to the transseptal cannula  22  and the coaxial balloon catheter  28 . However, the balloon  62  remains sufficiently inflated to maintain the contact between the tip  50  and the balloon  62 . The coaxial balloon catheter  28  and the tip  50  are advanced, as a unit, further into the left atrium  21  while the distal sleeve  36  is held in position. In this way, the left atrial anchor  38  extends beyond the distal sleeve  36  of the delivery apparatus  26  and is deployed within the volume of the left atrium  21 . The delivery apparatus  26  is then retracted from the left atrium  21 , the intra-atrial septum  20 , and the right atrium  24 . Once deployed, struts  51  may have a diameter that is at least 1.1 times, but smaller than about 3 times, the diameter of the orifice created by the tip  50  through the intra-atrial septum  20 ; however, the diameter of the struts  51  in the expanded state is limited primarily by the patient&#39;s anatomy. Also, once deployed, the distal tip  50  can extend about 3 mm from the deployed left atrial anchor  38 . 
     Continuing now to  FIG. 4E , the physician can ensure proper deployment of the struts  51  by in vivo visualization of a radiopaque marker (not shown) on the struts  51 . Once the struts  51  are fully deployed, the transseptal cannula  22  and the coaxial balloon catheter  28  are slightly retracted so that the struts  51  engage the intra-atrial septum  20  within the left atrium  21 . 
     With the left atrial anchor  38  deployed at the intra-atrial septum  20 , a right atrial anchor  88  can be implanted, which will now be described in detail with reference to  FIGS. 5A-5B . 
       FIG. 5A  illustrates the details of the right atrial anchor  88  and a right atrial anchor delivery system  89 . The right atrial anchor  88  has at least two opposed struts  94  coupled to a tip  96 , where the struts  94  are operable to move from a contracted state (shown in solid) to an extended state (shown in phantom). The struts  94  may be machined from a tubular structure formed using wire or formed from a flat sheet stock, as was described in U.S. patent application Ser. No. 12/256,911. The wire or flat sheet stock may be any shape-memory material (such as nickel titanium, NiTi, or MP35N). While many shapes for the struts  94  are possible, the shape shown includes an angled portion  94   a  and a contact portion  94   b  in the extended state. The contact portion  94   b  will contact the intra-atrial septum  20  ( FIG. 1 ). The angled portion  94   a  allows the right atrial anchor  88  to accommodate a wide range of anatomies and septal wall thicknesses. The angled portion  94   a  also creates a force that will resist a distal movement of the transseptal cannula  22  once the right atrial anchor  88  is properly attached to the left atrial anchor  38  and implanted in the intra-atrial septum  20  ( FIG. 1 ). 
     The tip  96  can be constructed in a manner that is similar to that described previously with respect to the tip  50  of the left atrial anchor  38 . 
     In some embodiments, the right atrial anchor  88  can include an anchor cuff  97  (shown in phantom) to promote localized tissue growth. The anchor cuff  97  can be a porous polymeric structure constructed from an implantable porous material (e.g., ePTFE, DACRON) as an inner cuff (not shown) and/or an outer cuff  97  similar to that described previously with the left atrial anchor  38 . In other embodiments, such as those provided in U.S. patent application Ser. No. 12/256,911, the right atrial anchor  88  may include a full disc (not shown) surrounding all of the struts  94 . The full disc can also be constructed from an implantable porous material (e.g., ePTFE, DACRON). While a separate full disc (not shown) could also surround all of the struts  51  of the left atrial anchor  38 , the configuration surrounding the struts  94  of the right atrial anchor  88  is preferred because the right atrium  24  is larger in volume than the left atrium  21 . 
       FIG. 5A  further illustrates the right anchor delivery apparatus  92  used to deliver the right atrial anchor  88  to the intra-atrial septum  20  ( FIG. 1 ). The right anchor delivery apparatus  92  has a proximal hub  98  and a distal sleeve  100  connected to the proximal hub  98  by at least one connector member  102  (two connector members  102  are shown). The proximal hub  98 , which can be molded from a single polymeric material, provides visual and tactile feedback to the physician throughout the surgical procedure. The connector members  102  are made of a single polymeric or metallic material and should be constructed with a low profile. The low profile allows the physician to maintain greater control over the transseptal cannula  22  while manipulating the right anchor delivery apparatus  92 . The distal sleeve  100  holds the right atrial anchor  88  during delivery to the transseptal cannula  22  and the intra-atrial septum  20  ( FIG. 1 ). In some embodiments, the distal sleeve  100  includes notches  104  into which the struts  94  of the right atrial anchor  88  rest. The notches  104  also contribute to an over-all low-profile assembly. The number of notches  104  should equal the number of struts  94  of the right atrial anchor  88 . 
       FIG. 5A  also illustrates the right anchor sheath  90 . The right anchor sheath  90  includes a distal sleeve  106  and a proximal hub  108  and sheath body configured to receive and move relative to the right anchor delivery apparatus  92 . The sheath body, as illustrated, includes a distal sleeve  106  that is connected to the proximal hub  108  by at least one connector member  110  (two connector members are shown). The distal sleeve  106  secures the struts  94  of the right atrial anchor  88  in a contracted state. The distal sleeve  106  may be constructed from single polymeric or multiple polymeric layers. The length of the distal sleeve  106  should cover the length of the struts  94  in the contracted state. 
     The proximal hub  108  provides the physician with visual and tactile feedback when the distal sleeve  106  is moved relative to the transseptal cannula  22 . The proximal hub  108  is typically molded from a single polymeric material and has sufficient rigidity so as to not be damaged or deformed during normal handling by the physician. The connector members  110  are constructed from a rigid polymeric material or metallic structure, such as a wire, and surround the transseptal cannula  22 . This arrangement creates a low profile and allows the physician to maintain direct control of the transseptal cannula  22  while manipulating the distal sleeve  106 . 
     As was previously described with the delivery apparatus  26  ( FIG. 2 ) used to deploy the left atrial anchor  38  ( FIG. 2 ), the right anchor sheath  90  may alternatively include a sheath extending from the proximal hub and for the length of the right anchor delivery apparatus  92 . The sheath is directed over the right anchor delivery apparatus  92  and secures the right atrial anchor  88  until deployment. 
       FIG. 5B  illustrates the assembled right anchor delivery system  89 , including the right anchor sheath  90  and the right anchor delivery apparatus  92  with the right atrial anchor  88 . The right anchor delivery system  89  is back-loaded over the guidewire  19 , the coaxial balloon catheter  28 , and the transseptal cannula  22 . 
     With the details of the right anchor delivery system  89  described with some detail, the method of implanting the right atrial anchor  88  can continue with reference to  FIGS. 6A-6J . 
       FIGS. 6A-6B  illustrate the method of assembling the right anchor delivery system  89 , and the loading of the right anchor delivery system  89  over the coaxial balloon catheter  28  and the transseptal cannula  22 . As shown, the proximal hubs  108 ,  98  may each include an alignment member  114 ,  116 , respectively. The alignment members  114 ,  116  maintain a radial alignment between the right anchor delivery apparatus  92  and the right anchor sheath  90  during the delivery of the right atrial anchor  88 . The alignment members  114 ,  116  can be molded as a portion of the respective proximal hubs  108 ,  98 . As also shown, the alignment members  114 ,  116  have similar perimeter shape; however, the alignment member  114  is formed as a negative image of the alignment member  116 . This structure allows the alignment member  114 ,  116  to mate and resist rotational movement. However, the particular shapes and arrangements shown should not be considered limiting. 
       FIG. 6C  illustrates the assembled right anchor delivery apparatus  92  and the loading of the right anchor delivery apparatus  92  and the right anchor sheath  90 , as a unit, over the right anchor delivery system  89  to the intra-atrial septum  20 . 
       FIG. 6D  illustrates the right atrial anchor  88  positioned at the intra-atrial septum  20 . The right atrial anchor  88  may now be attached to the tip  50  by way of a mechanical connection, such as a friction or interference fit, a magnet, or a screw thread. The struts  94  are then deployed, as described below. 
       FIG. 6E  illustrates the right anchor delivery apparatus  92  positioned against the intra-atrial septum  20  as the distal sleeve  106  is retracted. After sufficient retraction, the struts  94  are released to automatically deploy from the contracted state (shown in solid in  FIG. 6D ) to a deployed state (shown in solid) against the intra-atrial septum  20 . 
       FIG. 6F  illustrates the right atrial anchor  88  having at least one locking member  118  on the inner diameter of the tip  96 . The at least one locking member  118  provides one manner of attaching and securing the tip  96  of the right atrial anchor  88  to the tip  50  ( FIG. 6E ) of the left atrial anchor  38  ( FIG. 6E ). The locking members  118  can include any manner of creating and maintaining a compression fit between the tip  96  of the right atrial anchor  88  and the tip  50  of the left atrial anchor  38 . 
       FIG. 6G  illustrates the retraction of the right anchor delivery apparatus  92  once the tip  96  of the right atrial anchor  88  is secured and the struts  94  are deployed. 
       FIG. 6H  then illustrates the deflating of the coaxial balloon catheter  28 . The syringe needle  124  of the syringe is inserted through the grommet  78  and into the fluid space  79  of the coaxial hub  56 . The inflation fluid is then withdrawn through the lumen  126  of the syringe needle  124  and into the syringe, which will decrease the fluid pressure within the balloon  62  and cause deflation. 
     After sufficient deflation, as shown in  FIG. 6I , the balloon  62  is released from its contact with the inner surface of the tip  50  and can be retracted. The coaxial balloon catheter  28  is then retracted, followed by the guidewire  19  shown in  FIG. 6J . 
     Though not specifically shown, after the guidewire  19  is removed it would be permissible for the physician to attach a hemostasis cuff (not shown) where the proximal end of the transseptal cannula  22  meets the incision into the right subclavian vein  15  and before attaching the transseptal cannula  22  to the pump of the circulatory assist device, and as disclosed in U.S. patent application Ser. No. 12/256,911. The hemostasis cuff seals the incision into the right subclavian vein  15  and may provide further resistance to movement of the transseptal cannula  22 . 
     Finally,  FIG. 6K  illustrates the implanted circulatory assist system. In that regard, the transseptal cannula  22 , which extends from the right and left atrial anchors  88 ,  38  to the superior incision site  14 , is attached to an inflow port  128  of an implantable pump  130  of the circulatory assist device. An outflow cannula  132  is coupled to the outflow port  134  of the pump  130 . The opposing end of the outflow cannula  132  is surgically attached as so to communicate with a suitable superficial artery, such as the right subclavian artery  136 . At this time, the physician may position the pump  130  subcutaneously or submuscularly within the superior incision site  14  or maintain the pump  130  externally even after the superior incision site  14  is closed. 
     While not specifically shown, the pump  130  can be operably associated with a controller (not shown), which may also be implanted or remain external to the patient  12 . A signal transmission means (not shown) is provided between the pump  130  and the controller and may be either a hard-wired or wireless communications device. In operation, the controller may regulate the pumping action of the pump  130 . Additionally, a memory device (not shown) may be included within the controller that will record pump activity for subsequent doctor evaluation and interaction. 
     The completed flow of blood according to a preferred embodiment will be as follows: oxygenated blood will exit the left atrium  21  via the natural path, into the left ventricle  138 , to the aorta  140 . From the aorta  140 , blood moves into the left subclavian artery  142 , the left common carotid artery  144 , and the brachiocephalic trunk  146 , which supplies oxygenated blood to the right common carotid  148  and the right subclavian artery  136 . Oxygenated blood will also enter the transseptal cannula  22  from the left atrium  21 . Blood entering the flexible cannula body  42  of the transseptal cannula  22  will travel through the lumen of the flexible cannula body  42  to the pump  130 . The pump  130  actively pumps blood into the outflow cannula  132  and into the right subclavian artery  136 . From here, the blood is directed into the remainder of the vascular network. 
     While the present invention has been illustrated by a description of various preferred embodiments and while these embodiments have been described in some detail, it is not the intention of the Applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The various features of the invention may be used alone or in any combination depending on the needs and preferences of the user. This has been a description of the present invention, along with the preferred methods of practicing the present invention as currently known. However, the invention itself should only be defined by the appended claims.