Abstract:
A ventricular assist device to provide cardiac assistance to a damaged ventricle chamber. The ventricular assist device is formed of an ventricle body which is anchorable to spaced ventricle wall portions to provide cardiac assistance. Operation of the ventricular assist device is timed or synchronized with the operating phases of the ventricle chamber. The ventricular assist device can be intravascularly deployed to provide a less invasive treatment procedure and can be adapted to provide static support if active assistance is no longer required.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to a cardiac device for treating cardiac disease. In particular, the present invention relates to a cardiac assist device for assisting with the blood pumping action of the heart.  
         [0002]     The heart pumps blood to the body from chambers of the heart. In particular, blood is pumped from a right ventricle through a pulmonary valve into the pulmonary artery for oxygenation by the lungs. Oxygenated blood flows into the left ventricle and is pumped from the left ventricle throughout the body. Blood flows into the ventricle chambers during a diastole phase where the ventricle chamber is dilated or relaxed and is pumped from the ventricle chamber during a systole phase when the heart muscle is contracted.  
         [0003]     The walls or muscle of a diseased heart can interfere with expansion or contraction of the heart or ventricles for systolic and diastolic phases. In particular, a diseased heart may include areas of non-contracting tissue, caused for example by a myocardial infraction, a hypoperfused area, or area of localized tissue death or necrosis. The non-contracting tissue may interfere with effective pumping during systole. In addition, a diseased heart may include areas that do not expand during diastole, thereby preventing proper filling of the ventricle chamber in preparation for the next systolic phase. Embodiments of the present invention provide solutions to these and other problems and offer advantages over the prior art.  
       SUMMARY OF THE INVENTION  
       [0004]     The present invention relates to a ventricular assist device to provide cardiac assistance to a damaged ventricle chamber. The ventricular assist device is formed of a ventricular body which is anchorable to spaced ventricle wall portions to provide cardiac assistance. Operation of the ventricular assist device is timed or synchronized with the operating phases of the ventricle chamber. The ventricular assist device can be intravascularly deployed to provide a less invasive treatment procedure and can be adapted to provide static support if active assistance is no longer required. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]      FIG. 1  is an illustration of a heart.  
         [0006]      FIG. 2  is an illustration of an embodiment of a ventricular assist device of the present invention deployed in a ventricle chamber.  
         [0007]      FIGS. 3-4  illustrate an embodiment of a ventricular assist device having an expanded length dimension ( FIG. 3 ) and a contracted length dimension ( FIG. 4 ) to provide ventricle assistance.  
         [0008]      FIG. 5  illustrates a ventricle chamber including a plurality of ventricular assist devices.  
         [0009]      FIG. 6  illustrates an embodiment of a ventricular assist device including an elongate body having an adjustable length dimension between opposed spaced ventricle anchors.  
         [0010]      FIG. 7  schematically illustrates an alternate embodiment of a ventricular assist device including an elongate body having an adjustable length dimension between opposed spaced ventricle anchors.  
         [0011]      FIGS. 8-11  illustrate alternate embodiments of a ventricular assist device having an actuatable length dimension to provide ventricle assistance.  
         [0012]      FIG. 12  illustrates an embodiment of ventricular assist device operable to provide cardiac assistance to a damaged ventricle chamber using a healthy ventricle chamber.  
         [0013]      FIGS. 13-14  schematically illustrate alternate embodiments of a ventricular assist device having a flexible body.  
         [0014]      FIGS. 15-16  schematically illustrate alternate embodiments of a ventricular assist device having a collapsible body  
         [0015]      FIG. 17  illustrates an embodiment of a ventricular assist device including an elongate body having an energizable dimension change.  
         [0016]      FIGS. 18-19  illustrate alternate embodiments of a ventricular assist device including an elongate body having an adjustable length dimension between opposed ventricle wall portions.  
         [0017]      FIGS. 20-21  schematically illustrate an embodiment for percutaneous transluminal deployment of embodiments of the ventricular assist device.  
         [0018]      FIG. 22  schematically illustrates an embodiment of a ventricular assist device.  
         [0019]      FIGS. 22-1  through  22 - 3  schematically illustrate an embodiment for connecting or attaching a ventricular assist device to a ventricle wall. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0020]      FIG. 1  is a sectional view of a heart  100  illustrating the left ventricle  102  and right ventricle  104  chambers of the heart. The left and right ventricles  102 ,  104  pump blood through the circulatory system of the body. In particular, blood is pumped from the right ventricle  104  to the pulmonary system for oxygenation and oxygenated blood is pumped from the left ventricle  102  throughout the body.  
         [0021]     As shown in  FIG. 1 , blood is supplied to the right ventricle  104  from the right atrium  106  through tricuspid valve  108  as illustrated by arrow  110 . Blood flows into the right atrium  106  from the superior vena cava  112  and inferior vena cava  114 . Blood is pumped from the right ventricle  104  through pulmonary valve  116  into the pulmonary artery  118  for oxygenation. Oxygenated blood returns via the pulmonary veins  120  and is pumped from the left ventricle  102  for distribution throughout the body. In particular, oxygenated blood is supplied to the left atrium  122  and flows into of the left ventricle  102  through a mitral valve  124 . Blood is pumped from the left ventricle  102  through aortic valve  126  through the aorta  128  for distribution throughout the body.  
         [0022]     The chambers of the left and right ventricles  102 ,  104  are enclosed by ventricle walls  129  which during a diastolic phase relax and dilate to fill the chamber with blood. During a systolic phase, the walls or muscle contract to pump blood for distribution as previously discussed. The walls of a diseased heart may include areas of non-contracting tissue which interferes with the pumping action of the heart.  
         [0023]     An area of non-contracting tissue may comprise a myocardial infraction or fibrous scarred tissue. Areas of non-contracting tissue may be caused by ischemia which is a decreased supply of blood to an area of tissue. Non-contracting tissue may also be the result of idiopathic disease or areas of necrosis or localized tissue death. An area of non-contracting tissue may also comprise tissue which is hibernating due to reduced blood flow to the affected tissue.  
         [0024]      FIG. 2  schematically illustrates an embodiment of a ventricular assist device  130  of the present invention. As shown, the ventricular assist device  130  includes an elongate body  132  transventricularly disposed and having an adjustable length dimension between opposed ventricular wall portions  134 - 1 ,  134 - 2  as illustrated by dotted lines in  FIG. 2 . As illustrated schematically, an actuator assembly  136  is coupled to the elongate body  132  and to a power or energy source  138  to expand or collapse the length of the elongate body  132  to provide cardiac assistance to expand or contract the ventricle chamber for operation. As shown, the actuator assembly  136  is coupled to a controller  140  to time or synchronize actuation of the elongate body  132  to the pumping (diastolic and systolic) phases of the heart.  
         [0025]     In one embodiment, the ventricular assist device can be transluminally implanted or inserted into the ventricular chamber for use, for example through a femoral artery as will be described. The schematically illustrated actuator assembly can be external or internally implanted and the power source can be an implantable power source or external power source. In a preferred embodiment, controller  140  receives input from sensing apparatus (not shown) which senses contraction and dilatation of the heart to time or synchronize operation of the assist device  130 . Such sensing apparatus can include electrical, displacement pressure, or other sensing.  
         [0026]      FIGS. 3-4  comparatively illustrate an embodiment of a ventricular assist device  130 - 3  having an elongate body  132 - 3  extending between opposed spaced ventricle anchors  144 ,  146  which are anchorable to opposed or spaced ventricle wall portions  134 - 1 ,  134 - 2  so that the elongate body extends across the ventricle chamber between opposed ventricle wall portions  134 - 1 ,  134 - 2  (i.e., transventricularly disposed). The elongate body  132 - 3  has an adjustable length dimension between the opposed spaced ventricle anchors  144 ,  146  to provide cardiac assistance to expand and/or contract the ventricle chamber for operation.  
         [0027]     Thus, as shown in  FIG. 3 , during the diastolic phase, the length of the elongate body  132 - 3  is extended so that the ventricle chamber fills and as shown in  FIG. 4 , during a systolic phase, the length of the elongate body  132 - 3  is contracted to assist contraction of the ventricle walls to pump blood from the ventricle chamber. The length of the elongate body  132 - 3  is adjusted via an actuator assembly  136  as illustrated schematically in  FIG. 2 . Anchor devices  144 ,  146  are schematically illustrated and it should be understood that application of the present invention is not limited to any particular ventricle anchor device.  
         [0028]     As illustrated in  FIG. 5 , ventricle or cardiac assistance can be provided by multiple or a plurality of ventricular assist devices  130 - 1 ,  130 - 2  cooperatively actuated to assist pumping operation of the ventricle chamber. In particular, in the embodiment shown, multiple transversely deployed devices extend across the ventricle chamber between opposed ventricle wall portions to provide cardiac assistance. An actuator assembly  136 - 1 ,  136 - 2  is coupled to each device  130 - 1 ,  130 - 2  and are synchronously powered as illustrated by block  148  to mimic pumping operation of the ventricle chamber. The synchronous operation may be simultaneous or concurrent operation, or there may be a time delay so that one ventricular assist device is actuated slightly earlier than another ventricular assist device. In this way a coordinated contraction can be obtained in a more efficient and effective manner, better coordinated with natural ventricle contraction.  
         [0029]     In assisting the pumping action of the chamber, the ventricular assist device(s)  130  exert expansive force to aid diastolic filling of the ventricle, or contraction force to aid systolic pumping of the ventricle, or both. Although a particular number of ventricular assist devices  130 - 1 ,  130 - 2  is shown, application of the present invention is not limited to the particular number or orientation shown nor a particular number or multiple separate actuators as shown.  
         [0030]      FIG. 6  illustrates an embodiment of a ventricular assist device  130 - 6  for ventricle pumping assistance. In the embodiment illustrated in  FIG. 6 , the elongated body  132 - 6  includes a cable  150  having a ventricle anchor  144 - 6  fixed to an end thereof. The cable  150  is slidably disposed through channel  152  of a sleeve portion of anchor  146 - 6  to define the elongate body  132 - 6  having an adjustable length portion or dimension between spaced ventricle anchors  144 - 6 ,  146 - 6  or ventricle wall portions. A driver  154  illustrated schematically is energized to move cable  150  along an actuation stroke to expand and contract the length dimension between ventricle anchors  144 - 6 ,  146 - 6 . For example, driver  152  can be pneumatically, hydraulically, electrically or magnetically powered to move cable  150  along the actuation stroke for pumping operation.  
         [0031]      FIG. 7  illustrates an embodiment of a ventricular assist device  130 - 7  including an elongate body  132 - 7  having a first tubular body portion  156  and a second body portion  158  slidably disposed in a lumen  160  of the first body portion  156  to provide the adjustable length dimension. As shown, ventricle anchors  144 - 7 ,  146 - 7  are fixed to the first and second body portions  156 ,  158  respectively and the second body portion  158  is slidable relative to the first body portion  156  as illustrated by arrow  162  to form the elongated body  132 - 7  having an adjustable length dimension between ventricle anchors  144 - 7 ,  146 - 7 . In the embodiment shown, the elongate body  132 - 7  is actuated between an expanded length dimension and a contracted length dimension via an actuator assembly  136 - 7  to slidably adjust the position of body portion  158  relative to body portion  156  to provide ventricular cardiac assistance.  
         [0032]      FIGS. 8-11  illustrate alternate embodiments of a ventricular assist device including an elongate body having first and second body portions  156 ,  158  slideable relative to one another. In the embodiment illustrated in  FIG. 8 , the second body portion  158  is slideably adjusted relative to the first body portion  156  along an actuation stroke via a cable  164  coupled to a driver  154 - 8 . Cable  164  is coupled to the second body portion  158  and driver  154 - 8 . Driver  154 - 8  is energized by a power source (not shown) to move the cable  164  along an actuation stroke as illustrated by arrow  166  to expand and contract the length dimension of the elongate body  132 - 8 . Driver  154 - 8  can be pneumatically, hydraulically, mechanically, electrically or magnetically powered. For example, the driver can include a pneumatic pump which is coupled to the cable, a motor assembly or the device can be actuated via a piezoelectric or shape memory material.  
         [0033]      FIG. 9  illustrates an alternate embodiment of a ventricular assist device  130 - 9  including an elongate body  132 - 9  having slidable body portions  156 ,  158 , as previously described. As shown, the elongate body  132 - 9  is transventricularly disposed and anchored relative to opposed ventricle wall portions as shown. In the illustrated embodiment body portion  158  is slidably adjusted relative to body portion  156  via an actuator assembly  136 - 9  including an internally disposed actuator  168  (illustrated schematically) in lumen  160  between the body portions  156 ,  158  to slidably move body portion  158  relative to body portion  156 .  
         [0034]     Actuator  168  is moved along an actuation stroke pneumatically, hydraulically, magnetically or electrically to slidably adjust body portion  158  relative to body portion  156  for pumping operation. For example, actuator  168  can include an internally disposed pneumatic pumping chamber or alternatively actuation can be provided by an internally disposed piezoelectric or shape memory material having an electric, thermal or magnetically induced dimension change to move body portion  158  relative to body portion  156 .  
         [0035]      FIGS. 10-11  illustrate alternate embodiments of a ventricular assist device including an elongate body having first and second body portions slideably relative to one another and an actuation assembly which supplies an actuation force to opposed ends of the elongate body to slidably adjust the first and second body portions for pumping operation, where like numbers are used to refer to like parts. In particular, in the embodiment illustrated in  FIG. 10 , opposed forces are supplied by a via clamp assembly  170  having opposed arm portions  172 ,  174  which supply force to opposed ends or portions of the elongate body  132 - 10  to slidably adjust body portions  156 ,  158 . An optional blood-contact sheath  159  may be used with any of the embodiments of the present invention. Blood-contact sheath  159  isolates the mating and sliding components of device  130  from blood and may bend, fold, stretch, compress, or accordion to provide a smooth continuous blood-contact surface.  
         [0036]     As shown, arm portions  172 ,  174  of the clamp assembly  170  move towards or away from one another as illustrated by arrows  176  via driver  154 - 10  (illustrated schematically) to open and close arm portions  172 ,  174  of the clamp assembly  170  for pumping operation. In an example embodiment, driver  154 - 10  can be formed of a piezoelectric or shape memory material which, when energized electrically, thermally or magnetically expands and contracts to open and close arm portions  172 ,  174  of the clamp assembly  170  for pumping operation. Alternatively, driver  154 - 10  can be a pneumatic, hydraulic or electrically driven device which moves arm portions  172 ,  174  along an actuation stroke.  
         [0037]     In an embodiment illustrated in  FIG. 11 , the ventricular assist device  130 - 11  includes first and second body portions  156 ,  158  which are pneumatically actuated via a pneumatic actuator assembly  180 . The pneumatic actuator assembly  180  includes a bladder  182  which is disposed about the ventricle chamber and aligned with opposed ends of the elongate body  132 - 11  to slidably adjust the body portions  156 ,  158  to expand and contract the length dimension of the elongate body  132 - 11  for pumping operation. As shown, pressure is supplied to the bladder  182  from a pressure source  184  as illustrated diagrammatically to fill the bladder  182  for pumping operations.  
         [0038]     Pressure is selectively supplied via a pump or driver  188  (illustrated diagrammatically) to operate the ventricular assist device  130 - 11  as described. In the illustrated embodiment of  FIG. 11 , body portion  158  is biased by spring assembly  186  in an extended position and is slidably contracted via expansion of bladder  182 . Pressure is selectively or controllably released from the bladder  182  to extend the elongate body  132 - 11  for pumping operation, although application is not limited to a spring biased assembly as shown.  
         [0039]      FIG. 12  illustrates an embodiment of a ventricular assist assembly which is powered by operation of a healthy ventricle chamber. In particular, contraction or expansion of the healthy chamber (i.e., ventricle  104 ) is transferred to assist contraction or expansion of a damaged ventricle chamber  102 .  
         [0040]     In the embodiment illustrated in  FIG. 12 , the assembly includes an elongate body  132 - 121  being compressible between ventricle anchors  144 - 12  and  146 - 12  during compression of diseased ventricle chamber  102  and being coupled to energy output means  190 . The assembly also includes an elongate body  132 - 122  being compressible between ventricle anchors  146 - 12  and  195 - 12  during compression of healthy ventricle chamber  104  and being coupled to energy input device  192 . The assembly or embodiment further includes an energy transfer device or means  194 . Energy transfer device  194  can be located at least in part within the heart as shown, or can be located external to the heart. Energy input device  192 , energy transfer device  194 , and energy output device  190  can utilize pneumatic, hydraulic, mechanical, electric, or magnetic energy.  
         [0041]     In use, systolic muscle compression of healthy ventricle  104  compresses elongate body  132 - 122 , actuating energy input means or device  192  which transfers energy via energy transfer means or device  194  to energy output means or device  190  which applies force to compress elongate body  132 - 121  thereby applying compressive force to aid compression of diseased ventricle  102 . As shown in  FIG. 12 , elongate bodies  132 - 121  and  132 - 122  can be configured as a single device with opposed aspects of ventricle anchor  146 - 12  being used in common. Alternatively, elongate bodies  132 - 121  and  132 - 122  can be separate devices requiring two separate ventricle anchors  146 - 12 . The separate devices allow elongate bodies of the devices to be located and oriented advantageously in particular regions of ventricles  102  and  104  which will provide the most effective ventricle assistance.  
         [0042]      FIG. 13  illustrates an alternate embodiment of a ventricular assist device  130 - 13 . In the illustrated embodiment, the ventricular assist device  130 - 13  is formed of an elongate body  132 - 13  having a flexible or bendable length as illustrated by dotted lines  196  between ventricle anchors  144 - 13 ,  146 - 13 . The elongate body  132 - 13  is bent or flexed to adjust a length dimension between the ventricle anchors  144 - 13 ,  146 - 13  via actuator assembly  136 - 13  to provide pumping operation.  
         [0043]      FIG. 14  illustrates an embodiment of an actuation assembly or system to flex or bend the flexible elongate body  132 - 13  for pumping operation. As shown, the assembly includes a cable  198  fixedly coupled to a ventricle anchor  144 - 14  and slidably coupled to ventricle anchor  146 - 14 . Cable  198  is moved along an actuation stroke via driver  154 - 14  as illustrated schematically to intermittently flex or bend the elongate body  132 - 13  for pumping operation. The driver  154 - 14  can be powered electrically, pneumatically, hydraulically or magnetically and although a particular, actuator assembly is illustrated, application is not limited to the particular actuation assembly illustrated.  
         [0044]     In an alternate embodiment illustrated in  FIG. 15 , ventricular assist device  130 - 15  includes an elongate body  132 - 15  formed of a collapsible tube  200 . The collapsible tube  200  provides a collapsible length dimension between ventricle anchors  144 - 15 ,  146 - 15  as illustrated schematically by dotted lines  202 . The collapsible tube or structure is normally biased in an extended or non-collapsed condition and is intermittently collapsed by actuator assembly  136 - 15  for pumping operation. Alternatively, the actuator assembly intermittently extends and collapses the collapsible elongate body for pumping operation.  
         [0045]      FIG. 16  illustrates an embodiment of an actuator assembly for collapsing a collapsible elongate body  132 - 16  having a collapsible length dimension between ventricle anchors  144 - 16 ,  146 - 16  for pumping operation. In particular, the actuator assembly includes cable  204  fixed to ventricle anchor  144 - 16  and slidable relative to ventricle anchor  146 - 16 . In the illustrated embodiment, cable  204  extends through lumen  206  of the collapsible tube  200 - 16  of elongate body  134 - 16  and is movable along an actuation stroke via driver  154 - 16  to collapse (and/or expand) tube  200 - 16  for pumping operation.  
         [0046]      FIG. 17  illustrates an alternate embodiment of a ventricular assist device  130 - 17  including an elongate body  132 - 17  having an adjustable length dimension. In the embodiment shown in  FIG. 17 , the elongate body  132 - 17  is formed of a material which has an electrical, thermal or magnetically induced dimension change so that energization of the elongate body  132 - 17  or portion thereof by a power supply  138  provides an adjustable length dimension as illustrated by dotted lines  210  of  FIG. 17 . In particular, the length of the elongate body  132 - 17  can be expanded or contracted between ventricle anchors  144 - 17  and  146 - 17  via energization of the material to provide intermittent pumping operation.  
         [0047]      FIG. 18-19  illustrate alternate ventricular assist device embodiments including an elongate body having an adjustable length dimension as illustrated by the dotted lines. In particular, in the embodiment illustrated in  FIG. 18 , the ventricular device  130 - 18  includes a “U” shaped plate or portion  212  which is coupled to opposed end portions of the elongate body  132 - 18  to transfer or distribute force to the ventricle wall via expansion or contraction of the elongate body  132 - 18  as previously described.  
         [0048]     In one embodiment, the “U” shaped plate  212  normally biases the ventricle chamber in an expanded profile and is actuated to compress the chamber for pumping operation. In another embodiment illustrated in  FIG. 19 , the ventricular assist device  130 - 19  includes opposed curved shaped plates  214 ,  216  coupled to opposed end portions of elongate body  132 - 19  (having an adjustable length dimension) and movable therewith to assist with pumping operations of the ventricle chamber.  
         [0049]     Embodiments of the ventricular assist device  130  can be surgically implanted or percutaneously intravascularly inserted for less invasive deployment. In particular, as schematically illustrated in  FIGS. 20-21 , the ventricular assist device  130  is inserted in a collapsed profile via catheter  220 . As shown in  FIG. 21 , the device is released from the catheter  220  for deployment. The device is remotely controlled via a tether assembly  222 . In the embodiment shown, a first end of the device (ventricle anchor  144 ) is secured to a first ventricle wall portion and thereafter, the device is expanded via operation of a release mechanism  224  to deploy the opposed end of the device (for example, ventricle anchor  146 ) into a second opposed ventricle wall portion.  
         [0050]     The release mechanism  224  can be a mechanical, magnetic or electric mechanism and can be remotely controlled or controlled via an intravascular connection as illustrated by dotted line  226  in  FIG. 21 . In particular, the mechanism  224  can be magnetically released or released by force or electrical current and application is not limited to any particular design. Once deployed, expansion and contraction of the elongate body is controlled via operation of an actuator (internal or external) coupled to a remote power source or internal power source. Should cardiac assistance no longer be necessary, the ventricular assist device described can be used as a passive support to limit distension of the ventricle walls or chamber.  
         [0051]     The embodiments shown in  FIGS. 18-19  can be modified as illustrated in  FIG. 22 .  FIG. 22  depicts an external “U” shaped member  212 - 22  coupled to the ventricle by ventricle anchors  144 - 22  and  146 - 22  but which does not span the inside of the ventricle between ventricle anchors  144 - 22  and  146 - 22 . A power source  138  and actuator  136 - 22  cause flexing of member  212 - 22  to form an elongate body actuatable to compress or expand the ventricle. Ventricle anchors  144 - 22  and  146 - 22  may pass all the way through the ventricle walls  129  as shown, or partway through, or be attached to the outer surface; through rivet-type  300 , helied wire type  302 , patch and suture type  306 , or other anchor, or an adhesive or thermal bond, as schematically illustrated in  FIGS. 22-1 ,  22 - 2 , and  22 - 3 .  
         [0052]     Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.