Abstract:
The invention provides an introducer assembly for delivering a blood pump into vasculature of a subject, as well as a method for utilizing the assembly.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims benefit of priority under 35 U.S.C. §119(e) of U.S. Patent Application Ser. No. 62/290,866, filed Feb. 3, 2016, the entire contents of which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Field of the Invention 
         [0003]    The invention relates generally to a cardiac assist device (CAD) and more particularly to a delivery tool, and a method of using the delivery tool for implanting and positioning a blood pump assembly of the CAD within a subject. 
         [0004]    Background Information 
         [0005]    The use of CADs is a well known method for treating heart failure. A blood pump (i.e., a balloon) is positioned inside the aorta, typically in the proximal descending aorta. The pump typically comprises a displacement volume of 40-50 cc, and works in series with the heart to augment blood flow. During diastole, the pump is inflated, thereby driving blood in the ascending aorta and aortic arch into the coronary arteries to supply oxygen to the heart muscle. During systole, as the left ventricle contracts, the pump is deflated so as to decrease the afterload. 
         [0006]    While the use and implantation of the blood pump portion of a CAD is well known, conventional methods of implantation may lead to infection as well as a risk of other complications. There exists a need for a blood pump delivery tool and method of delivering a blood pump into the vasculature of a subject which provides convenience as well as reduced risk of complications. 
       SUMMARY OF THE INVENTION 
       [0007]    The invention provides an introducer assembly for delivering a blood pump into the vasculature of a subject, as well as a method for utilizing the assembly. 
         [0008]    Accordingly, in one aspect, the invention provides an introducer assembly for introducing a blood pump. The assembly includes: a) a shaft elongated along a longitudinal axis, the shaft having a distal end, a proximal end, a lumen extending along the longitudinal axis from the distal end to the proximal end, and a collet mechanism disposed at the proximal end for receiving a guidewire; and b) a locking component having a distal end and a proximal end, the locking component adapted such that the distal end of the locking component reversibly couples to the proximal end of the shaft. The locking component has a locked configuration and an unlocked configuration such that when in the locked configuration, a gripping force is created between the collet mechanism and the guidewire. 
         [0009]    In another aspect, the invention provides a method of introducing a blood pump into a blood vessel of a subject utilizing an introducer assembly of the invention. The method includes providing an introducer assembly for introducing the blood pump, elongating the inflatable balloon by advancing a guidewire distally along the lumen of the introducer shaft through the collet mechanism and toward the distal end of the balloon when the locking component is in an unlocked configuration, transitioning the locking component to the locked configuration such that the guidewire is slidably immovable within the collet, advancing the balloon into and along a length of vasculature, such as a blood vessel, transitioning the locking component to the unlocked configuration, withdrawing the guidewire, and disconnecting the distal end of the shaft from a drive line of the blood pump. In embodiments, a vacuum force may be applied to the inflatable balloon after the locking component is transitioned to the locked configuration. In one embodiment, the balloon is advanced through an access port of an arterial interface device (AID) of the CAD system which provides access to the blood vessel. In a related embodiment, a sheath is applied over the introducer assembly and the access port before advancing the balloon into the blood vessel. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The invention will be better understood from a reading of the following detailed description taken in conjunction with the drawings in which like reference designators are used to designate like elements, and in which: 
           [0011]      FIG. 1  schematically shows a CAD, also referred to herein as an intravascular Ventricular Assist System (iVAS), including blood pump  180 , internal drive line  170 , arterial interface device (AID)  150 , skin interface device (SID)  400 , external drive line  310 , external driver  320 , and subcutaneous ECG leads  850  superimposed on a human thorax; 
           [0012]      FIG. 2  schematically shows an introducer assembly  50  for use with implanting a blood pump of a CAD in a patient; 
           [0013]      FIG. 3  is a cross-sectional view of the introducer assembly of  FIG. 2 ; 
           [0014]      FIG. 4  is an expanded cross-sectional view of locking component  90  and associated collet mechanism  75  of the introducer assembly of  FIGS. 2 and 3 ; 
           [0015]      FIG. 5  schematically shows introducer assembly  50  coupled to blood pump  180  during implantation of the blood pump  180  into a patient; 
           [0016]      FIG. 6A  schematically shows portions of a CAD implanted in a patient using AID  150 ; 
           [0017]      FIG. 6B  is a cross-sectional view of AID  150  of  FIG. 6A ; 
           [0018]      FIG. 7A  illustrates SID  400  comprising implantable base  500  and SID cap  600 ; 
           [0019]      FIG. 7B  illustrates a supracutaneous portion  420  and a subcutaneous portion  430  of the SID  400  of  FIG. 7A  when disposed within a patient; 
           [0020]      FIG. 8  shows an access port assembly  800  used to occlude vascular graft  110  during implantation of a blood pump; 
           [0021]      FIG. 9  shows an assembly of introducer assembly  50  in combination with an access port assembly  800  and optional sheath  810  during implantation of a blood pump with optional sutures  820  being disposed on opposing openings of the sheath  810 ; 
           [0022]      FIG. 10  is an expanded cross-sectional view of a distal portion of blood pump  180  in which a blunt tip  85  of guidewire  80  is advanced to the distal tip of the blood pump during delivery; 
           [0023]      FIG. 11  shows an assembly of introducer assembly  50  in combination with a vacuum device  900  (i.e., syringe) during implantation of a blood pump; 
           [0024]      FIG. 12  schematically shows blood pump  180  positioned in the proximal descending aorta, with the pump&#39;s inflation catheter entering the vasculature at the right subclavian artery through AID  150 ; and 
           [0025]      FIG. 13  schematically shows a CAD including blood pump  180 , internal drive line  170 , AID  150 , SID  400 , external drive line  310 , and external driver  320 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    U.S. patent application Ser. Nos. 14/659,375 and 14/476,656, and U.S. Pat. Nos. 8,323,174 and 7,892,162 are incorporated herein in their entireties. The components, devices, modules, source code, and the like, associated with the CAD and components thereof as disclosed in U.S. patent application Ser. Nos. 14/659,375 and 14/476,656, and U.S. Pat. Nos. 8,323,174 and 7,892,162 are also disposed in the CAD and components thereof as described herein. In addition, the functions and methods disclosed in U.S. patent application Ser. Nos. 14/659,375 and 14/476,656, and U.S. Pat. Nos. 8,323,174 and 7,892,162, that utilize those components, devices, modules, source code, and the like, are also operative using the CAD described herein. 
         [0027]    This invention is described in preferred embodiments in the following description with reference to the Figures, in which like numbers represent the same or similar elements. Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment. 
         [0028]    The described features, structures, or characteristics of the invention may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are recited to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention may be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention. 
         [0029]    While the introducer assembly of the present invention is generally disclosed with use of a CAD of the disclosure, it may be utilized with a variety of devices and in a variety of procedures which involve vascular implantation of a blood pump device. 
         [0030]    In a primary embodiment, the CAD of the disclosure, also referred to herein as an iVAS, operates on the principle of counterpulsation similar to an intra-aortic balloon pump (IABP). Components of the system are shown in  FIG. 1 . During diastole, inflation of blood pump  180  augments the native heart&#39;s cardiac output by displacing blood in the aorta, pushing it downstream. At the start of systole (peak of the R-wave), the blood pump  180  deflates, decreasing aortic pressure and reducing the work required of the left ventricle during subsequent ejection. Counterpulsation has been a standard treatment for cardiogenic shock for decades, providing circulatory support for hours to weeks. 
         [0031]    In various embodiments, implantation of an iVAS requires implanting four components: AID  150 , blood pump  180 , SID  400 , and internal drive line  170 . To facilitate implantation, custom tools and methodology were developed, including the introducer assembly of the present invention. 
         [0032]    Accordingly, in one aspect, the invention provides an introducer assembly for introducing a blood pump. With reference to  FIGS. 2-4 , the assembly  50  includes: a) a shaft  55  elongated along a longitudinal axis, the shaft having a distal end  60 , a proximal end  65 , a lumen  70  extending along the longitudinal axis from the distal end  60  to the proximal end  65 , and a collet mechanism  75  disposed at the proximal end  65  for receiving a guidewire  80 ; and b) a locking component  90  having a distal end and a proximal end, the locking component adapted such that the distal end of the locking component reversibly couples to the proximal end of the shaft. The locking component has a locked configuration and an unlocked configuration such that when in the locked configuration, a gripping force is created between the collet mechanism  75  and a guidewire  80  inserted within lumen  70 . 
         [0033]    Notably, the proximal end  65  of the shaft is adapted to form a fluid tight seal with the locking component  90 . This can be accomplished by inclusion of o-ring  95 . The fluid tight seal prevents blood loss during introduction of the blood pump  180  into the vasculature. The o-ring  95  also creates an air tight seal between the introducer and the blood pump  180  allowing the blood pump to be deflated during insertion into the vasculature. 
         [0034]      FIGS. 6A and 6B  illustrate an AID  150  of the iVAS of the disclosure. Referring to  FIG. 6A , a vascular interface  100  is formed using a vascular graft  110  attached to an artery  120  with a suture ring  130  at the position of an incision in the artery. The particular graft shown flares at its distal end  140 . AID  150  sits inside the graft  110 , filling the interior of the graft  110 . 
         [0035]    Sewing the suture ring  130  to the subclavian artery is the first task the surgeon performs when implanting the system. Next, graft  110  is sutured to the suture ring  130 . 
         [0036]    With reference to  FIGS. 6A and 6B , AID  150  comprises a body  155 . In certain embodiments, body  155  comprises a polyurethane. In certain embodiments, body  155  comprises a polysiloxane. In the illustrated embodiment of  FIGS. 1A and 1B , body  155  is Ruined to include two lumens extending therethrough. Lumen  160  is utilized to pass internal drive line  170  through AID  150 . 
         [0037]    The second lumen  165  houses a pressure sensor  190  to measure arterial pressure, and sensor leads  192 ,  194 ,  196 , and  198 , to interconnect sensor  190  to SID  400  ( FIGS. 7A and 7B ). Sensor leads  192 ,  194 ,  196 , and  198 , are used to provide power to sensor  190 , provide a ground connection, to provide clock signals to sensor  190 , and to communication arterial pressure signals from sensor  190  to SID  400 . 
         [0038]    Lumen  160  which extends through the length of the AID  150  is filled by the internal drive line  170 . Internal drive line  170  in turn is connected at its distal end to a pump  180 . In certain embodiments, inflation catheter is formed to have an inner diameter in the range 3 to 6 mm (often about 5 mm), although other diameters are possible as well. 
         [0039]    Not shown in  FIG. 6A  is the proximal end of the drive line  170 . Because the pump  180  needs to inflate and deflate in coordination with the cardiac cycle in order to function as a ventricular assist device, the blood pump  180  must be in fluid communication with a driver (e.g., an air compressor or pump) via drive line  170 . 
         [0040]    In embodiments wherein such a driver is external to the body as shown in  FIG. 1 , the SID  400  ( FIGS. 7A and 7B ) allows the design of the system to be composed of parts both implanted and external to the patient&#39;s body. The drive line  170  is attached to SID  400 , and SID  400  is attached to the fluid driver. In certain embodiments, the driver  320 , the drive line  170  and the pump  180  form a closed air system, wherein that closed system includes a well-defined and precisely controlled volume of air. Such a well-defined and precisely-controlled volume of air facilitates leak detection. 
         [0041]    In certain embodiments, air volume and movement of air is precisely controlled using, for example and without limitation, a bellows driven by one or more linear actuators. In descriptions of the skin interface device herein, the drive line  170  is alternatively referred to as an internal drive line. 
         [0042]    With reference to  FIGS. 8 and 9 , in implantation of the blood pump  180 , once the anastomosis of the suture ring  130  and graft  110  is complete as discussed above, an access port assembly  800  containing an iris valve ( FIG. 8 ) is inserted into graft  110  at its proximal end creating hemostasis. The surgeon then optionally attaches a sheath  810  ( FIG. 9 ) to the proximal end of the access port assembly  800 . Inside the sheath  810  is the blood pump  180  in its deflated state. The other end of the sheath  810  is tied off to the shaft of the introducer assembly  50  as illustrated in  FIG. 9 . The sheath  810  is attached to the access port assembly  800  and shaft of the introducer assembly  50  via sutures  820 . The function of the access port is to minimize blood loss during pump insertion. The sheath is used to collect any blood that escapes through the access port. The blood pump  180  is then implanted in the patient&#39;s vasculature, i.e., the descending thoracic aorta. To implant the pump, the surgeon inserts and guides it down the patient&#39;s subclavian artery, traverses the subclavian aorta bifurcation, and then travels down the aorta to the final location. The pump does not have the mechanical rigidity to permit implantation without the introducer  50 . 
         [0043]    In embodiments, the sheath is not required in implantation. In such embodiments, in implantation of the blood pump  180 , once the anastomosis of the suture ring  130  and graft  110  is complete as discussed above, an access port assembly  800  containing an iris valve ( FIG. 8 ) is inserted into graft  110  at its proximal end creating hemostasis. The sheath is not required since graft  110  may be reversibly clamped to prevent blood loss. The blood pump  180  is then implanted in the patient&#39;s vasculature, i.e., the descending thoracic aorta. To implant the pump, the surgeon inserts and guides it down the patient&#39;s subclavian artery, traverses the subclavian aorta bifurcation, and then travels down the aorta to the final location. The pump does not have the mechanical rigidity to permit implantation without the introducer  50 . 
         [0044]    During installation of the blood pump  180 , guidewire  80  is inserted into the blood pump  180  so the wire&#39;s blunt distal end contacts  85  the distal inside tip of the pump ( FIG. 10 ). Thus the guidewire  80  is within the central lumen of the blood pump  180  during insertion as opposed to being in an auxiliary lumen or on the outside surface of the balloon. The distal end of the introducer shaft is then mechanically attached to the proximal end of the pump as shown in  FIG. 5 . Collet mechanism  75  and associated locking component  90  are used to lock the guidewire  80  into place. A vacuum device  900  (i.e., a syringe as in  FIG. 11 ) is then used to pull a vacuum on the blood pump (not shown) minimizing its size. Once the blood pump is placed, the vacuum is released, the guidewire  80  is extracted and the shaft is removed. 
         [0045]    In embodiments, the access port assembly  800  may be removed during implantation of the blood pump  180 . As such, the inner diameter of the port may be sized large enough such that it can accommodate the AID  150  and the introducer assembly  50 . For example, once the blood pump  180  is placed within the artery, the access port assembly  800  may be detached and slid away from the patient over the introducer assembly  50  and guidewire  80 . In embodiments, the inner diameter of the access port is greater than about 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15 mm. In one embodiment, the inner diameter of the access port is equal to or greater than about 7 or 8 mm. 
         [0046]    To facilitate placement and detection of the blood pump  180  during installation, the guidewire  80 , or portion thereof, may include a radiopaque material. For example, blunt end  85  may be composed of or otherwise include a radiopaque material. Alternatively, the blood pump  180 , or portion thereof, may include a radiopaque material. In another embodiment, both the guidewire  80 , or portion thereof, and the blood pump  180 , or portion thereof include a radiopaque material. 
         [0047]      FIG. 12  shows (schematically) the graft  110  in position on the right subclavian artery. This position is advantageous because it allows easy surgical access and a relatively short distance to the descending aorta.  FIG. 12  also shows the graft secured to AID  150  by a suture  210 . Other suitable positions for the interface include either common carotid artery, the brachiocephalic artery, the left subclavian artery, the descending aorta, and the abdominal aorta. Downstream branches of the aorta may also be used, such as the external iliac and femoral arteries. 
         [0048]    Referring now to  FIG. 13 , in embodiments a CAD or iVAS comprises pump  180 , internal drive line  170 , AID  150 , SID  400 , external drive line  310 , and external driver  320 . 
         [0049]    In embodiments, blood pump  180  is sized and shaped to dangle inside a patient&#39;s aorta and may optionally include a radiopaque material. In certain embodiments, the wall of the pump comprises moisture resistant material, or may be entirely moisture resistant, to keep the air inside the pump as dry as possible. One possible moisture resistant material for the pump comprises polyurethane. In certain embodiments, the one or more polyurethane polymers are modified to include surface silicone end groups. 
         [0050]    At its proximal end, the pump  180  is connected to the distal end of the drive line  170 . An AID  150  is sized and shaped to pass the drive line  170  through an arterial wall. 
         [0051]    SID  400  connects the proximal end of the internal drive line  170  to the distal end of the external drive line  310 . The proximal end of the external drive line  310  is connected to the driver  320 . 
         [0052]    The pump  180 , the internal drive line  170 , the SID  400 , the external drive line  170 , and the driver  320  can be charged with a pumping medium. In certain embodiments, the pumping medium comprises a fluid. A preferred pumping medium is air. In certain embodiments, pump  180 , the internal drive line  170 , the SID  400 , the external drive line  310 , and the driver  320  define a closed fluid system. In certain embodiments, pump  180 , the internal drive line  170 , the SID  400 , the external drive line  310 , and the driver  320  comprise an open system, wherein the bolus of air inside the system can be exchanged with the ambient environment. 
         [0053]    As those skilled in the art will appreciate, pump  180  may have various sizes depending on the anatomy of the patient. In certain embodiments, pump  180  will typically have an inflated volume of about 40 to 60 cubic centimeters when inflated to 10 to 20 mmHg above the maximum systolic pressure. 
         [0054]    In certain embodiments, sensors are connected to one or more communication interfaces that, like the pneumatic drive line  170 , pass through the AID  150  and graft  110  and connect to SID  400 . In certain embodiments, these one or more communication interfaces provide data to a controller. 
         [0055]    In certain embodiments, one or more sensors transmit data, by wire or wirelessly, to Applicants&#39; SID  400 . Examples of sensors include, without limitation, electrical leads to measure an electrocardiogram, sensors to detect body temperature, sensors to detect blood analytes (such as blood gases), sensors to detect intra-arterial pressure directly or indirectly, and/or sensors to measure humidity within pump  180 . Indirect sensors include, for example and without limitation, a microphone to monitor heart sounds. 
         [0056]    In certain embodiments, a controller  530  is disposed in SID  400 . In certain embodiments, a controller  530  is integral with external driver  320 . 
         [0057]    In certain embodiments, signals from one or more sensors are used by controller  530  to monitor the cardiac cycle and, thereby, the counterpulsation cycle. In certain embodiments, combinations of signals from one or more sensors are used by controller  530  to monitor the cardiac cycle. 
         [0058]    In certain embodiments, sensors are used to determine the state of the air inside the system. In certain embodiments, air pressure is measured to determine whether the pump is properly inflating, or if there is a leak in the system. In certain embodiments, data from the air pressure sensor is communicated to controller  530 . 
         [0059]    In certain embodiments, sensors for arterial blood pressure at the pump  180  and/or at the AID  150  are in communication with controller  530 . In certain embodiments, these sensors communicate a detected arterial blood pressure to the controller  530 , either by wire or wirelessly. 
         [0060]    Referring now to  FIG. 7A , SID  400  comprises a SID base  500  and a SID cap  600 . SID base  500  and SID cap  600  are coupled so as to create an air-tight conduit between the internal drive line  170  and external drive line  310 . In this way, drive line  170 , SID  400 , and drive line  310 , can be part of a closed fluid system. In certain embodiments, an air-tight seal is formed using gaskets and other sealing systems. 
         [0061]    Referring now to  FIGS. 7A and 7B , when implanted skin interface device  400  includes a SID base  500 , comprising a subcutaneous portion  430  internal to the patient, in combination a supracutaneous portion  420 . SID cap  600  is attached to the supracutaneous portion  420  of SID base  500 . Those skilled in the art will appreciate that it is possible to implant SID  400  in a variety of different locations on the patient, for example abdominally or thoracically. 
         [0062]    Referring now to  FIG. 7A , SID  400  wirelessly provides electrical energy from SID cap  600  to SID base  500 , and also wirelessly and bi-directionally passes electrical signals, i.e., data, between SID cap  600  and SID base  500 . In order to optimize the transmission of power from SID cap  600  to SID base  500 , and at the same time optimize the transmission of data between SID cap  600  and SID base  500 , Applicants have “decoupled” the transmission of power from the transmission of data. The transmission of power from SID cap  600  to SID base  500  is done by induction. 
         [0063]    While the preferred embodiments of the present invention have been illustrated in detail, it should be apparent that modifications and adaptations to those embodiments may occur to one skilled in the art without departing from the scope of the present invention as set forth herein. The invention is illustrated in part by the following example, provided however, that the invention is solely defined by the appended claims.