CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation in part of application Ser. No. 10/622,129 filed on Jul. 16, 2003 which is hereby incorporated by reference.
BACKGROUND The present invention is directed to methods and devices for altering the function of the left ventricle. The methods and devices may be used to alter the function of the left ventricle for any reason. For example, the methods and devices of the present invention may be useful in treating congestive heart failure (CHF), ventricular aneurysms or dilation of the heart for other reasons such as coronary artery disease, hypertension, infection, or malfunctioning heart valve. The present invention may also find uses in treating ventricular septal defects or perforations of the left ventricular wall.
Various devices for altering the function of the left ventricle have been suggested. The present invention is directed to alternative devices for altering the function of the left ventricle.
SUMMARY The present invention provides devices and methods for altering blood flow in the left ventricle and reducing pressure on an isolated or non-blood flow side. An element is provided which is movable between collapsed and expanded conditions. The element is collapsed within a delivery device and advanced into the left ventricle in the collapsed condition. The element is then expanded in the left ventricle and secured to the wall of the left ventricle to form a circumferential attachment to the wall of the left ventricle. The element separates the left ventricle into a blood flow side and a non-blood flow side with the element forming a hemostatic seal at the circumferential attachment so that pressure in the blood flow side is not communicated to the non-blood flow side. In this manner, the cyclical pressure in the left ventricle is not fully communicated, if at all, to the non-blood flow side.
The present invention is also directed to devices and methods for reducing the volume of the non-blood flow side. A reduction in volume may provide remodeling benefits when treating a dilated heart since the dilated heart often has an inefficient geometry for pumping. The volume may be reduced and maintained in a reduced volume with the element forming a hemostatic seal. The volume may be reduced by simply evacuating blood from the non-blood flow side. The volume may also be reduced by manipulating the wall of the left ventricle from within the left ventricle or using a tool which engages the outside of the heart. The volume may be reduced until a part of the wall of the left ventricle moves into contact with the element.
The element may be secured below the papillary muscles or another suitable location. For example, the element may be secured above the papillary muscles when treating a ventricular septal defect. The element may be advanced through a peripheral vessel or directly through a wall of the left ventricle. The element may be generally shaped to provide a desired geometry of the left ventricle wall. For example, the element may have an outer surface which is generally convex and has an apex.
The present invention also provides devices and methods for displacing the heart and maintaining the displaced condition with the element. The heart may be displaced by pulling, compressing or twisting the heart in a desired manner.
These and other aspects of the invention are described in the following description of the preferred embodiment, drawings and claims.
DESCRIPTION OF DRAWINGSFIG. 1 shows a system which is used to alter blood flow through the left ventricle.
FIG. 2 shows an element contained within a delivery device.
FIG. 3 shows the delivery device introduced into the left ventricle through the aortic valve with a balloon expanding the element.
FIG. 4 shows a catheter positioned to collapse the non-blood flow side of the left ventricle.
FIG. 5 shows the non-blood flow side collapsed further.
FIG. 6 shows a needle piercing the non-blood flow side to evacuate blood from the non-blood flow side.
FIG. 7 shows a material introduced into the evacuated part of the left ventricle.
FIG. 8 shows the delivery device introduced directly through the wall of the left ventricle.
FIG. 9 shows the element partially expanded in the left ventricle.
FIG. 10 shows the element fully expanded and the delivery device removed.
FIG. 11 shows a needle piercing the left ventricle to evacuate the non-blood flow side.
FIG. 12 shows a retractable element.
FIG. 13 shows the element ofFIG. 12 retracted after expansion.
FIG. 14 shows an element which everts within the left ventricle.
FIG. 15 shows a catheter used to evacuate the non-blood flow side prior to everting the element ofFIG. 14.
FIG. 16 shows the element ofFIG. 14 everted.
FIG. 17 shows an external member which engages the element and a tool used to secure the element to the wall of the left ventricle.
FIG. 18 shows the tool being used to deliver RF energy to secure the element to the wall of the left ventricle.
FIG. 19 shows another tool used to secure the element to the wall of the left ventricle.
FIG. 20 shows the heart displaced prior to deploying the element.
FIG. 21 shows the element deployed after displacing the heart.
FIG. 22 shows another tool used to twist the heart.
FIG. 23 shows the heart twisted and the non-blood flow side evacuated using the tool.
FIG. 24 shows an endovascular tool for twisting the heart.
FIG. 25 shows the element expanded while the heart is twisted.
FIG. 26 shows the non-blood flow side collapsed.
FIG. 27 shows the non-blood flow side collapsed and attached to the element in a biased position.
FIG. 28 shows the element extending obliquely along the septum to exclude a ventricular septal defect, free ventricular wall perforation or exclusion of akinetic ventricular septum or wall.
FIG. 29 shows another support member in an expanded position.
FIG. 30 shows a side view of the support member ofFIG. 29.
FIG. 31 shows the support member collapsed.
FIG. 32 is a side view of the support member ofFIG. 31.
FIG. 33 shows the support member attached to the left ventricle when expanded.
FIG. 34 shows the support member attached to the left ventricle when collapsed.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring toFIGS. 1 and 2, a system2 for altering blood flow through the left ventricle is shown. The system2 includes adelivery device4 for delivering anelement6 which is implanted in the left ventricle. Theelement6 is collapsed within thedelivery device4 and then expanded in the left ventricle. Theelement6 may be secured to the wall of the left ventricle in any suitable location as discussed below such as below the papillary muscles PM.
FIG. 1 shows thedelivery device4 introduced into the femoral artery. Thedelivery device4 may, of course, be delivered through other vessels and may even be introduced directly through an opening in the left ventricle as described below. Thedelivery device4 may simply be a catheter8 which has alumen10 for containing theelement6. Thedelivery device4 may, of course, include other features described below. Endovascular delivery of theelement6 is preferred, although not required for various aspects of the invention, since surgical procedures may have unacceptable risk for some patients.
Theelement6 is movable between the collapsed and expanded shapes ofFIGS. 2 and 3. Theelement6 may be naturally biased to the expanded shape or may be expanded into the desired shape with a balloon12 (FIG. 3), a mechanical mechanism or due to use of shape-memory materials coupled with a temperature change. The system2 may include a balloon inflation lumen13 and a source ofinflation fluid15, such as saline, for inflating the balloon12 (FIG. 1). Theelement6 ofFIG. 3 has piercingelements14, such as barbs, hooks harpoons, or any other suitable anchoring element to secure theelement6 to the wall of the left ventricle. Theelement6 may also be secured using an energy source, such as RF, to secure the element to the wall of the left ventricle as described below. Theelement6 may also be attached to the heart by evacuating blood to create a vacuum-type seal between theelement6 and the heart. As will also be discussed below, another tool may be introduced into the chest to manipulate the heart tissue and/or secure theelement6 to the left ventricle.
Theelement6 has a generally convexouter surface16 with an apex18. The shape of theouter surface16 is selected so that the heart will assume a more desirable shape as will be described further below. Theelement6 also forms a recess20 formed by a concaveinner surface22. Theelement6 may be used to help remodel the left ventricle wall to restore the wall to a more natural shape. To this end, theelement6 may have a generally conical shape or a generally elliptical shape similar to the area around the apex of the heart (seeFIGS. 4 and 5).
Theelement6 has acover24 with a number ofsupport members26 secured to thecover24. Thesupport members26 extend generally toward the apex18. Thesupport members26 may be coupled to one another at or near the apex18 or to acentral member29 near the apex18. Thesupport members26 are attached to acircumferential band28, which may be elastic, extending around the proximal end. Thesupport members26 may, for example, exert a radial force equal in sum to the left ventricular end diastolic filling pressure to secureelement6 to the left ventricular wall circumferentially and hemostatically. Thesupport members26 may be oriented in a manner which permits distortion particularly in a manner favoring contraction of the left ventricle. For example, thesupport members26 may be somewhat flexible to permit the heart to contract. Thesupport members26 may be formed of any suitable material such as a stainless steel, a plastic polymer, or a superelastic material such as nitinol. Thecover24 may be any suitable biologic or biocompatible material such as mammalian (bovine or porcine) fixed pericardium, Gortex or Dacron. In particular, it may be desirable to quickly induce tissue ingrowth along the edges of the element to help seal and separate the left ventricle at thecircumferential band28. Of course, theelement6 may be formed in any other suitable manner.
Referring toFIGS. 12 and 13, anotherelement6A is shown wherein the same or similar reference numbers refer to the same or similar structure. Theelement6A may be retracted after expansion so that repositioning of theelement6A is possible if initial placement is not satisfactory. For example, referring toFIG. 12, atether30 or the like extends throughloops32 in theelement6A. Thetether30 is tensioned to cinch thetether30 in theloops32 thereby retracting theelement6A as shown inFIG. 13.
Referring toFIGS. 14-16, anotherelement6B is shown which is everted when deployed. Theelement6B is initially expanded as shown inFIG. 14. Theelement6B may be expanded into engagement with the wall of the left ventricle using piercing elements such as curved barbs, hooks or needles similar to the piercingelements14 of element6 (FIGS. 2-4). If the position of theelement6B is not satisfactory, theelement6B may be collapsed by simply advancing thedelivery device4 over theelement6B to collapse theelement6B. Theelement6B can then be repositioned and expanded again. Once theelement6B has been expanded into the desired position, theelement6B is everted as shown inFIG. 16. The piercing elements may be somewhat curved so that when theelement6A is everted the piercing elements penetrate further into the tissue. Theelement6B may provide advantages in preventing thrombus or other emboli, which may be adhered to the wall of the left ventricle near the apex in akinetic or dyskinetic areas, from being dislodged and migrating past theelement6B since theelement6B is already expanded prior to being permanently anchored. As will be described below, blood in the isolated area of the left ventricle may be evacuated prior to everting theelement6B.
Referring again toFIGS. 2-4, the system2 may also include afilter40 which prevents thrombus or other emboli dislodged from within the left ventricle from escaping. Thefilter40 may be positioned in the left ventricle which may help stabilize the system2 in the left ventricle when deploying theelement6. Thefilter40 is preferably expanded as shown inFIG. 4 prior to expanding and securing theelement6 to the wall of the left ventricle. It may be desirable to expand thefilter40 before deploying theelement6,6A or manipulating the heart so that any thrombus dislodged during deployment or manipulation will be caught by thefilter40. Of course, thefilter40 may also be positioned at the aortic valve or in the ascending aorta without departing from the scope of the present invention. Thefilter40 may be part of thedelivery device4 or may be a separate device.FIG. 4 shows thefilter40 as part of thedelivery device4 with theelement6 being delivered through thefilter40.
Use of the system2 is now described with reference toelement6, however, it is understood that the description concerning the use of any of the elements is equally applicable to the other elements described herein or another suitable element. Before introducing theelement6 into the left ventricle, it may be necessary to determine the appropriate size and geometry of theelement6. This can be performed before introduction of the device using various known visualization techniques. The size and geometry of theelement6 may be selected to achieve a desirable shape for the heart. For example, theelement6 may help restore a dilated heart toward a more normal geometry. Of course, the present invention may be accomplished with a number of different sizes and geometries or theelement6 itself may be flexible enough to accommodate a range of size requirements. The present invention may also be practiced with theelement6 being specifically designed with the particular geometry of the patient's heart in mind including not only the overall geometry of the heart and left ventricle but also the size and extent of non-functioning areas and the location of transition zones between functioning and non-functioning areas.
In some applications, theelement6 is secured to the wall of the left ventricle at or near the transition zone between functioning and non-functioning parts of the wall of the left ventricle. In this manner, the amount of functioning wall of the left ventricle remaining in the blood flow path is maximized. For other applications, it may be desirable to secure theelement6 just within functioning parts of the wall of the left ventricle. For example, theelement6 may be somewhat compliant or resilient so that the heart is not overly restrained during contraction. Of course, theelement6 may also simply be positioned at a more fixed location such as below the papillary muscles. For example, the element may be positioned less than one cm below the papillary muscles. This position may be within the functioning part of the wall of the left ventricle thereby excluding some portion of the wall of the left ventricle upon deployment of theelement6.
As mentioned above, thedelivery device4 may be used to deliver theelement6 endovascularly when introduced through a peripheral vessel such as the femoral artery as shown inFIG. 1. Of course, theelement6 may be delivered through other endovascular paths such as a venous route across the atrial septum into the left atrium, and then across the mitral valve into the left ventricle. Theelement6 is held in the collapsed position by thedelivery device4. Thedelivery device4 is passed through the aortic valve and into the left ventricle. Theelement6 is then moved out of thedelivery device4 by advancing theelement6 and/or retracting thedelivery device4. Theelement6 may now be expanded and secured to the wall of the left ventricle. Theelement6 may naturally expand into engagement with the wall or may be balloon expanded or mechanically expanded (FIG. 3). The filter40 (FIG. 4) may be expanded prior to expansion of theelement6 within the left ventricle to prevent any thrombus dislodged during the procedure from migrating downstream.
Once theelement6 is secured to the wall of the left ventricle, theelement6 has essentially separated the left ventricle into a blood flow side and a non-blood flow side. The blood flow side continues to form part of the blood flow path through the heart while the non-blood flow side, or isolated side, does not. The blood on the non-blood flow side may be partially or completely evacuated through thedelivery device4, aseparate catheter50 which is subsequently removed (FIG. 4), or simply with aneedle51 which pierces the wall of the left ventricle (FIG. 6). Evacuation of blood may provide the benefits described below such as partial remodeling of the heart wall and reduction in further dilation of the heart.
The blood may be evacuated until at least part of the wall of the left ventricle on the non-blood flow side moves into contact with theelement6 or until a low pressure threshold is reached (FIG. 7). Evacuation of blood may also create a vacuum-type seal between the heart and theelement6 which can be used to secure or help secure theelement6 to the heart. When using theelement6B ofFIGS. 14-16 in particular, the isolated or non-blood flow side is partially evacuated prior to everting theelement6B as shown inFIG. 15 so that pressure does not build in the isolated side and impede the element from everting as shown inFIG. 16. After everting theelement6B, further evacuation of blood may be desirable. Of course, various aspects of the present invention may be practiced without evacuating blood from the isolated side.
The isolated side may also be injected with a material52 after removing some or all of the blood as shown inFIG. 7 to fill any space which may exist between the element and the isolated part of the heart. Thematerial52 may be used to induce thrombus formation in any remaining space in the isolated region and may render theelement6 hemostatic. Alternatively, thematerial52 may have adhesive qualities which help hold the wall of the left ventricle in the collapsed shape after evacuating the blood. As shown inFIG. 7, the distended portion of the wall is somewhat wrinkled after evacuating blood from the isolated region. Thematerial52 may help prevent the wrinkled portion from re-expanding. Of course, the isolated region may not re-expand simply due to the fact that theelement6 forms a seal with the wall of the left ventricle thereby preventing blood from entering the isolated region to re-expand or re-inflate the isolated region. Thematerial52 may be delivered through thedevice4 from a source of the material55 (seeFIG. 1) or through thecatheter50 orneedle51.
Referring toFIG. 17, anexternal member65 may also be provided which traps the wall of the left ventricle. Theexternal member65 may be a band which locks to theelement6 by itself or a number ofparts67 which engage theelement6 and are delivered by atool69 from outside the heart. For example, eachpart67 may lock to one of the piercingelements14 as shown inFIG. 18 with or without use of theexternal member65 or band. Referring toFIG. 18, anattachment tool62 may also be used to help form a circumferential seal between theelement6 and the wall of the left ventricle. Theattachment tool62 may deliver energy, such as RF energy, to secure theelement6 to the left ventricle wall. Thedelivery device4 orelement6 itself may also include another electrode (not shown) for use of bipolar RF.
Referring toFIG. 19, anotherattachment tool63 is shown which is used to attach theelement6 to other parts of the left ventricle. Thetool63 drives anattachment element65 through the left ventricle wall and into engagement with theelement6. For example, thetool63 may be asuturing device64 which delivers asuture71 to attach theelement6 to the heart. Securing theelement6 to the wall of the left ventricle at locations other than the circumferential region may help provide a fluid tight seal around theelement6. Securing theelement6 to the left ventricle may also be used to retain desired displacements and loads or to achieve a desired shape as described further below. Thetool63 andelement6 may be configured so that thetool63 may be used to attach theelement6, such as parts of thecover24, to the heart at locations selected by the user.
Referring toFIGS. 20-27, the system2 may also be used in combination with atool54 which manipulates the heart and/or helps to secure theelement6 to the left ventricle. Thetool54 may be used to change the shape of the heart or to move or displace the heart into engagement with theelement6 as necessary. For example, it may be desirable to alter the geometry of the left ventricle prior to attachment of theelement6. The altered geometry may help to restore a more advantageous geometry for pumping or it may be used to place the left ventricle under compression, tension or torsion. For example, it may be desirable to compress or tension the heart prior to attaching theelement6 so that the left ventricle wall is under compression when secured to theelement6 as shown inFIG. 21. Once the heart is tensioned or compressed as desired, theelement6 can be deployed. Theelement6 may help to retain part or all of the desired displacement or loading on the heart.
It may also be desirable to twist the heart, such as in the direction favoring contraction of the left ventricle, so that theelement6 and/or left ventricle is naturally biased toward the contracted state. Referring toFIGS. 22 and 23, for example, the heart may be twisted and then anchored to theelement6 to maintain a torsional load on the heart. Aheart twisting tool70 may include asuction cup72 or other device for holding and engaging the heart. Thetool70 may also have aneedle74 or the like to pierce and evacuate the non-blood flow side as mentioned above. Thetool70 is used to twist or rotate the heart and then evacuate the blood as shown inFIG. 23. Thetool70 may be used prior to expanding theelement6 so that theelement6 itself helps the heart wall to retain the desired shape. Referring toFIGS. 25-27, thedelivery device4 itself may also have anelement80 which engages and twists the heart. Theelement80 may simply be a relatively robust wire or tube having piercingelements82 which pierce the heart wall and transmit torque to the heart. The isolated or non-blood flow side may then be evacuated and theelement6 withdrawn to permit the heart to collapse and remodel as described herein and shown inFIGS. 26 and 27. Thus, it can be appreciated that the heart may be displaced or distorted before attaching theelement6 to the left ventricle. Of course, the heart may be twisted or torqued before, during or after evacuating blood from the isolated region to provide the desired loads, displacement and/or shape of the heart.
The wall of the left ventricle may also be attached to theelement6 apart from the circumferential connection to theelement6. In this manner, the desired changes in the shape of the heart, which may be thought of as partial or complete remodeling of the heart, is maintained. Referring again toFIG. 19, thetool63 may be used to secure the left ventricle to theelement6. Theelement6 may be attached to the heart using theattachment element65 driven through the heart and into engagement with theelement6. Theattachment element65 may be thesuture67 or any suitable structure such as a staple, suture, or anchor. Of course, theattachment element65 may also be driven into the wall of the left ventricle from within the left ventricle using thedelivery device4 or another suitable device. Theattachment element65 is driven through the wall of the left ventricle after expansion of theelement6 and may occur after manipulating the heart as desired. The wall of the left ventricle may also be attached to theelement6 using an energy source, such as RF, which attaches or adheres theelement6 to the wall of the left ventricle similar to thetool62 ofFIG. 18.
Referring now toFIGS. 29-34, still another element100 is shown which may be used to alter the function and blood flow through the left ventricle. The element100 may be used and in any manner described herein. The element100 has asupport member102 which hasflexible portions104 which permit thesupport member102 to expand and contract as necessary. Theflexible portions104 are generally V-shaped but may take other shapes. Thesupport member102 may be manufactured of any suitable material such as nitinol.
Thesupport member102 is configured to contract from the expanded configuration ofFIGS. 29 and 30 to the collapsed configuration ofFIGS. 31 and 32. diastolic pressure in the left ventricle may be approximately equal to the expansile force of thesupport member102 so that thesupport member102 can help to expand the ventricle. The element100 may also have acover106 which provides the advantages of the covers described above. Thecover106 may have any of the features of the other covers described above, such as the ability to evert, as mentioned above.
The element100 may be delivered and used in any manner described herein and those methods are expressly incorporated here. For example, the element100 may be delivered through a blood vessel or directly through a penetration in the heart.
The present invention also provides the ability to treat a septal defect SD or other opening or tear in the septum or a perforation P in the left ventricle free wall by isolating the defect or opening by isolating that portion with the element as shown inFIG. 28. The element6C may be delivered endovascularly or percutaneously providing obvious advantages over a purely surgical procedure. The element6C ofFIG. 28 may have a more eliptical opening depending upon the desired geometry of the element6C and the heart. The element6C may also be used to treat a perforation of the left ventricle as also shown inFIG. 28.
Theelement6 may also be delivered directly through a penetration in the left ventricle. Referring toFIGS. 8-11, for example, the left ventricle may be accessed directly through a surgical incision in the left ventricle. Thedelivery device4 is introduced through the opening in the left ventricle with purse string sutures81 maintaining hemostasis. This procedure, and deployment of theelement6, may take place under bypass or while the heart is beating. If the patient's heart has non-functioning regions near the apex, such as is often the case with a dilated or ischemic heart, working through an opening in that part of the heart, such as near the apex, may be easier to maintain while the heart is beating. After introduction through the opening in the left ventricle wall or endovascular delivery as described herein, theelement6 is expanded in the left ventricle in any suitable manner. Theelement6 may be expanded by itself or expanded with the balloon12 (FIG. 3) or a mechanical device. Furthermore, any suitable tool, such as those described herein, may be used to manipulate the heart or to secure theelement6 to the left ventricle wall as described above and those methods and devices are expressly incorporated here.
Depending upon the particular cardiac condition being treated, theelement6 may also help reduce future dilation of an already dilated heart. First, the isolated area is often a non-functioning and/or dilated region. Eliminating or reducing blood flow pressure in the isolated area may reduce or prevent further dilation due to the blood pressure. Theelement6 also provides a mechanical advantage to the dilated left ventricle by isolating the non-contracting and dilated segments. Theelement6 may also reduce the radius of curvature of the non-isolated and/or functioning portion of the left ventricular wall. The reduction in radius of curvature may reduce wall stress and work of the non-isolated area. Finally, theelement6 may also provide physical support for the heart to reduce or prevent further dilation and also provide physical remodeling of the heart and a mechanical advantage which can further reduce dilation.
It can be appreciated that the present invention may be practiced in a number of different ways with varying devices without departing from the scope of the invention. For example, the element may be attached closer to the apex or the element may be formed from two or more parts delivered independently.