The present disclosure relates to devices and associated methods for treating and improving the performance of a heart. More particularly, the present disclosure relates to devices and methods that passively assist to reshape a dysfunctional heart to improve its performance. For example, in some embodiments, the apparatus of the present disclosure may be directed toward reducing the wall stress in the failing heart. In other embodiments, the devices and methods disclosed herein may be used to treat a heart valve, such as, for example, a mitral valve.
The syndrome of heart failure is a common course for the progression of many forms of heart disease. Heart failure may be considered to be the condition in which an abnormality of cardiac function is responsible for the inability of the heart to pump blood at a rate commensurate with the requirements of the metabolizing tissues, or can do so only at an abnormally elevated filling pressure. There are many specific disease processes that can lead to heart failure with a resulting difference in pathophysiology of the failing heart, such as the dilatation of the left ventricular chamber. Etiologies that can lead to this form of failure include idiopathic cardiomyopathy, viral cardiomyopathy, and ischemic cardiomyopathy.
The process of ventricular dilatation is generally the result of chronic volume overload or specific damage to the myocardium. In a normal heart that is exposed to long term increased cardiac output requirements, for example, that of an athlete, there is an adaptive process of slight ventricular dilation and muscle myocyte hypertrophy. In this way, the heart fully compensates for the increased cardiac output requirements. With damage to the myocardium or chronic volume overload, however, there are increased requirements put on the contracting myocardium to such a level that this compensated state is never achieved and the heart continues to dilate.
The basic problem with a large dilated left ventricle is that there is a significant increase in wall tension and/or stress both during diastolic filling and during systolic contraction. In a normal heart, the adaptation of muscle hypertrophy (thickening) and ventricular dilatation maintain a fairly constant wall tension for systolic contraction. However, in a failing heart, the ongoing dilatation is greater than the hypertrophy and the result is a rising wall tension requirement for systolic contraction. This is felt to be an ongoing insult to the muscle myocyte resulting in further muscle damage. The increase in wall stress is also true for diastolic filling. Additionally, because of the lack of cardiac output, there is generally a rise in ventricular filling pressure from several physiologic mechanisms. Moreover, in diastole there is both a diameter increase and a pressure increase over normal, both contributing to higher wall stress levels. The increase in diastolic wall stress is felt to be the primary contributor to ongoing dilatation of the chamber.
Therefore there is a need to devise effective techniques that could improve valve function without the need for cardiopulmonary bypass and without requiring major remodeling of the valve. In particular, passive techniques to change the shape of the heart chamber and/or associated valve and reduce regurgitation while maintaining substantially normal leaflet motion may be desirable. Further, advantages may be obtained by a technique that reduces the overall time a patient is in surgery and under the influence of anesthesia. It also may be desirable to provide a technique for treating valve insufficiency that reduces the risk of bleeding associated with anticoagulation requirements of cardiopulmonary bypass. In addition, a technique that can be employed on a beating heart would allow the practitioner an opportunity to assess the efficacy of the treatment and potentially address any inadequacies without the need for additional bypass support
The embodiments of the present disclosure have several features, no single one of which is solely responsible for their desirable attributes. Without limiting the scope of the present embodiments as expressed by the claims that follow, their more prominent features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled “Detailed Description”, one will understand how the features of the present embodiments provide advantages, which include a non-pharmacological, passive method and device for the treatment of a failing heart. The method and the heart treatment device is configured to reduce the tension in the walls of a heart. It is believed to reverse, stop or slow the disease process of a failing heart as it reduces the energy consumption of the failing heart, decrease in isovolumetric contraction, increases sarcomere shortening during contraction and an increase in isotonic shortening in turn increases stroke volume. The device reduces wall tension during diastole (preload) and systole.
In one embodiment, a method for improving the function of a heart is provided. The method comprises providing a plurality of anchoring members; providing an elongate member and a release mechanism connected to the elongate member, the release mechanism being configured to releasably engage with each of the plurality of anchoring members; the elongate member being configured to store energy exerted by a heart chamber during systole, and release the stored energy during diastole to assist the heart chamber to return to an uncompressed state; selecting one of the plurality of anchoring members; positioning the elongate member transverse a chamber of the heart; and engaging the release mechanism with the selected anchoring member so as to releasably attach the elongate member to the selected anchoring member.
In another embodiment, a heart treatment device is provided. The heart treatment device for improving the function of the heart comprises a plurality of anchoring members; an elongate member configured to be positioned transverse a chamber of the heart; where the elongate member has a substantially rigid distal end, a substantially rigid proximal end and a substantially elastic portion between the distal end and the proximal end; and a release mechanism connected to the elongate member, the release mechanism being configured to releasably engage with each of a plurality of anchoring members having differing configurations to releasably attach the elongate member to each of the plurality of anchoring members one at a time.
The features, functions, and advantages of the present embodiments can be achieved independently in various embodiments, or may be combined in yet other embodiments.
The embodiments of the present disclosure will now be discussed in detail with an emphasis on highlighting the advantageous features. These embodiments depict the novel and non-obvious device for improving the heart function shown in the accompanying drawings, which are for illustrative purposes only. These drawings include the following figures, in which like numerals indicate like parts.
Aside from the structural and procedural arrangements set forth above, the invention could include a number of other arrangements, such as those explained hereinafter. It is to be understood that both the foregoing and the following descriptions are exemplary. The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the invention and, together with the description, serve to explain certain principles.
The various aspects of the devices and methods described herein generally pertain to devices and methods for treating heart conditions, including, for example, dilatation, valve incompetencies, including mitral valve leakage, and other similar heart failure conditions. Each disclosed device may operate passively in that, once placed in the heart, it does not require an active stimulus, either mechanical, electrical, or otherwise, to function. Implanting one or more of the devices operates to assist in the apposition of heart valve leaflets to improve valve function.
In addition, these devices may either be placed in conjunction with other devices that, or may themselves function to, alter the shape or geometry of the heart, locally and/or globally, and thereby further increase the heart's efficiency. That is, the heart experiences an increased pumping efficiency through an alteration in its shape or geometry and concomitant reduction in stress on the heart walls, and through an improvement in valve function.
However, the devices disclosed herein for improving valve function can be “stand-alone” devices, that is, they do not necessarily have to be used in conjunction with additional devices for changing the shape of a heart chamber or otherwise reducing heart wall stress. It also is contemplated that a device for improving valve function may be placed relative to the heart without altering the shape of the chamber, and only altering the shape of the valve itself.
The devices and methods described herein offer numerous advantages over the existing treatments for various heart conditions, including valve incompetencies. The devices are relatively easy to manufacture and use, and the surgical techniques and tools for implanting the devices do not require the invasive procedures of current surgical techniques. For instance, the surgical technique does not require removing portions of the heart tissue, nor does it necessarily require opening the heart chamber or stopping the heart during operation. For these reasons, the surgical techniques for implanting the devices disclosed herein also are less risky to the patient than other techniques. The less invasive nature of these surgical techniques and tools may also allow for earlier intervention in patients with heart failure and/or valve incompetencies.
The devices and methods described herein involve geometric reshaping of the heart and treating valve incompetencies. In certain aspects of the devices and methods described herein, substantially the entire chamber geometry is altered to return the heart to a more normal state of stress. Models of this geometric reshaping, which includes a reduction in radius of curvature of the chamber walls with ventricular splints, may be found in U.S. Pat. Nos. 5,961,440 and 6,050,936, the entire disclosures of these patents are incorporated herein by reference. Prior to reshaping the chamber geometry, the heart walls experience high stress due to a combination of both the relatively large increased diameter of the chamber and the thinning of the chamber wall. Filling pressures and systolic pressures are typically high as well, further increasing wall stress. Geometric reshaping reduces the stress in the walls of the heart chamber to increase the heart's pumping efficiency, as well as to stop further dilatation of the heart.
Although the methods and devices are discussed hereinafter in connection with their use in the left ventricle and for the mitral valve of the heart, these methods and devices may be used in other chambers and for other valves of the heart for similar purposes. One of ordinary skill in the art would understand that the use of the devices and methods described herein also could be employed in other chambers and for other valves of the heart. The left ventricle and the mitral valve have been selected for illustrative purposes because a large number of the disorders occur in the left ventricle and in connection with the mitral valve.
The following detailed description of exemplary embodiments of the present invention is made with reference to the drawings, in which similar elements in different drawings are numbered the same. The drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the invention.
With reference to
For purposes of discussion and illustration, several anatomical features of the human heart are labeled as follows: left ventricle LV; right ventricle RV; left atrium LA; ventricular septum VS; right ventricular free wall RVFW; left ventricular free wall LVFW; atrioventricular groove AVG; mitral valve MV; tricuspid valve TV; aortic valve AV; pulmonary valve PV; papillary muscle PM; chordae tendeneae CT (or simply chordae); anterior leaflet AL; posterior leaflet PL; annulus AN; ascending aorta AA; coronary sinus CS; right coronary artery RCA; left anterior descending artery LAD; and circumflex artery CFX.
Both the anterior pad 14 and the posterior pad 16 are seated on the epicardium, while the tension member 12 extends through the myocardium and the ventricular chamber(s). This position also allows for the mitral valve splint 10 to have both pads 14, 16 placed epicardially, avoiding the need to position a pad interior to any of the heart chambers. To avoid interference with mitral valve MV function, the pads 14, 16 may be positioned such that the tension member 12 extends inferiorly of the of the leaflets AL/PL and chordae CT of the mitral valve MV. To maximize shape change effects of the mitral valve MV, and in particular the papillary muscles PM and/or annulus AN, the posterior pad 16 may have an inferior contact zone 20 and a superior contact zone 22, positioned on the epicardial surface proximate the papillary muscles PM and annulus AN, respectively.
The posterior pad 16 may be positioned such that the superior contact zone 22 rests in, or proximate to, the atrioventricular groove AVG, which is adjacent the annulus AN of the mitral valve MV. In this position, the application of deforming forces brought about by the posterior pad 16 causes a direct deformation of the annulus AN of the mitral valve MV, and/or repositioning of the papillary muscles PM. Both of these actions contribute to better coaptation of the leaflets AL, PL, minimizing or eliminating mitral valve regurgitation.
The anterior pad 14 may be positioned on the epicardial surface of the right ventricle RV, proximate the base of the right ventricular outflow track, and close to the intersection of the right ventricular free wall RVFW and the interventricular septum VS. In this position, the function of the right ventricle is minimally impacted when the splint 10 is tightened. Also in this position, the anterior pad 14 avoids interference with important blood vessels as well as important conduction pathways. For example, as seen in
The position of the splint 10 as shown in
The mitral valve splint 10 may improve mitral valve function through a combination of effects. First, the shape of the annulus AN is directly altered, preferably during the entire cardiac cycle, thereby reducing the annular cross sectional area and bringing the posterior leaflet PL in closer apposition to the anterior leaflet AL. Second, the position and rotational configuration of the papillary muscles PM and surrounding areas of the left ventricle LV are further altered by the tightening of the splint 10. This places the chordae CT in a more favorable state of tension, allowing the leaflets AL, PL to more fully appose each other. Third, since the annulus AN of the mitral valve MV is muscular and actively contracts during systole, changing the shape of the annulus AN will also reduce the radius of curvature of at least portions of the annulus AN, just as the shape change induced by ventricular splints discussed hereinbefore reduces the radius of at least significant portions of the ventricle. This shape change and radius reduction of the annulus AN causes off-loading of some of the wall stress on the annulus AN. This, in turn, assists the annulus's ability to contract to a smaller size, thereby facilitating full closure of the mitral valve MV during systole.
These effects are illustrated in
As mentioned hereinbefore, the mitral valve splint 10 generally includes an elongate tension member 12 secured to an anterior pad or anchor 14 and a posterior pad or anchor 16. The pads 14, 16 may essentially function as epicardial anchors that engage the heart wall, do not penetrate the heart wall, and provide surfaces adjacent the exterior of the heart wall to which the tension member 12 is connected.
Tension member 12 may comprise a composite structure including an inner cable to provide mechanical integrity and an outer covering to provide biocompatibility. By way of example, not limitation, the inner cable of tension member 12 may have a braided-cable construction such as a multifilar braided polymeric construction. In general, the filaments forming the inner cable of the tension member 12 may comprise high performance fibers. For example, the inner cable may comprise filaments of ultra high molecular weight polyethylene available under the trade names Spectra™ and Dyneema™, or the inner cable may comprise filaments of some other suitable material such as polyester available under the trade name Dacron™ or liquid crystal polymer available under the trade name Vectran™.
The filaments forming the inner cable may be combined in yarn bundles of approximately 50 individual filaments, with each yarn bundle being approximately 180 denier. For example, two bundles may be paired together (referred to as 2-ply) and then braided with approximately 16 total bundle pairs to form the inner cable. The braided cable may include, for example, approximately 20 to 50 picks per inch (number of linear yarn overlaps per inch), such as approximately 30 picks per inch. The inner cable may have an average diameter of approximately 0.030 to 0.080 inches, for example, or approximately 0.055 inches, with approximately 1600 individual filaments. Further aspects of the inner cable of the tension member 12 are described in U.S. patent Ser. No. 09/532,049, now U.S. Pat. No. 6,537,198, filed Mar. 21, 2000, entitled A SPLINT ASSEMBLY FOR IMPROVING CARDIAC FUNCTION IN HEARTS, AND METHOD FOR IMPLANTING THE SPLINT ASSEMBLY (hereinafter referred to as the “049 patent application”), the entire disclosure of which is incorporated herein by reference.
When formed within the parameters indicated above, the inner cable permits the tension member 12 to withstand the cyclical stresses occurring within the heart chamber without breaking or weakening; provides a strong connection to the pads 14, 16; minimizes damage to internal vascular structure and the heart tissue; and minimizes the obstruction of blood flow within the heart chamber. Although exemplary parameters for the inner cable of the tension member 12 have been described above, it is contemplated that other combinations of material, yarn density, number of bundles, and pick count may be used, so as to achieve one or all the desired characteristics noted above.
The outer covering surrounding the inner cable of the tension member 12 may provide properties that facilitate sustained implantation in the heart. In particular, because tension member 12 may be in blood contact as it resides within a chamber of the heart H, the outer covering provides resistance to thrombus generation. Furthermore, because of the relative motion that occurs between the heart H and certain portions of tension member 12 passing through the heart chamber walls, the covering allows for tissue ingrowth to establish a relatively firm bond between the tension member 12 and the heart wall, thus reducing relative motion therebetween and minimizing potential irritation of the heart wall.
The outer covering surrounding the inner cable of the tension member 12 may be made of a porous expanded polytetrafluoroethylene (ePTFE) sleeve. The ePTFE material is biostable and tends not to degrade or corrode in the body. The ePTFE sleeve may have an inner diameter of approximately 0.040 inches and a wall thickness of approximately 0.005 inches, for example, prior to placement around the inner cable of the tension member 12. The inner diameter of covering may stretch to fit around the inner cable to provide a frictional fit therebetween. The ePTFE material of the covering may have an internodal distance of between approximately 20 and approximately 70 microns, such as approximately 45 microns, for example. This may permit cellular infiltration and thus result in secure ingrowth of the adjacent heart wall tissue so as to create a tissue surface on the tension member 12 residing in the heart chamber. The ePTFE material, particularly having the internodal spacing discussed above, has a high resistance to thrombus formation and withstands the cyclic bending environment occurring in the heart. Further aspects of the outer covering of the tension member 12 are described in the '049 patent application. Although ePTFE has been described as a suitable material for the outer covering of the tension member 12, other suitable materials exhibiting similar characteristics may also be used.
The anterior pad 14 and the posterior pad 16 of the mitral valve splint 10 are connected to opposite ends of the tension member 12. To facilitate delivery of the splint 10 as described in more detail hereinafter, one of the anchor pads 14, 16 may be fixed and locked to the tension member 12 prior to implantation. The other of the anchor pads 14, 16 may be initially adjustable and subsequently fixed to the tension member 12. In particular, its position along the length of the tension member 12 may be adjusted during implantation, prior to fixation to the tension member 12. The posterior pad 16 may be positioned proximate the posterior leaflet PL of the mitral valve MV and may be fixed relative to tension member 12. The anterior pad 14 may be positioned near the intersection of the right ventricle RV and ventricular septum VS, and may be initially adjustable relative to tension member 12 and subsequently fixed thereto.
In the exemplary embodiments described herein, the anterior pad 14 is an adjustable pad, but may be fixed as well. The anterior pad 14 may have a substantially circular shape as shown in
With reference to
With reference to
The tension member 12 may intersect the bridge 28 of the posterior pad 16 closer to the inferior end 24 than the superior end 26 as seen in
Other posterior pad 16 shapes and sizes are also contemplated, possessing varying numbers and positions of contact zones, possessing varying distances between the contact zones and the tension member, and possessing varying shapes and sizes of contact zones. For example, as shown in
In addition to variations of the design of posterior pad 16, it is also contemplated that variables associated with the position of the pad 16 and forces applied to the pad 16 by the tension member 12 may be selected as a function of, for example, the particular manifestation of mitral valve dysfunction and/or as a function of the particular anatomical features of the patient's heart. These variables may affect the magnitude, area, and/or specific location of displacement of the left ventricular free wall LVFW proximate the mitral valve MV structures (annulus AN, leaflets AL/PL, chordae CT, and/or papillary muscles PM).
With continued reference to
The posterior pad 16 may incorporate a releasable connection mechanism 40 that allows the pad 16 to be removed from the elongate tension member 12 and replaced, for example, by a different pad with an alternate shape and size, depending on the particular anatomy of the heart H and/or the desired effects on the heart. It may be desirable, for example, to utilize a pad 16 that has a longer bridge 28 with greater spacing between the contact zones 20, 22 to minimize mitral regurgitation (MR). Although the connection mechanism 40 allows the pad 16 to be removed from the tension member 12 and replaced with another pad 16, the position of the pad 16 may remain fixed in that the final position of the pad 16 along the linear aspect of the tension member 12 is fixed, as opposed to the adjustable anterior pad 14 discussed hereinbefore.
The releasable connection mechanism 40 may comprise a block 42 which fits into a recessed region 44 within the pad bridge 28, as best seen in
As illustrated in
In an alternate embodiment illustrated in
It is important to note that while an exemplary embodiment of a mitral valve splint 10 is described above, variations are also considered within the scope of the disclosure. Mitral valve and cardiac anatomy may be quite variable from patient to patient, and the mitral valve splint design and implant position may vary accordingly. For example, the location of the regurgitant jet may be centered, as shown in
With reference to
The positioning and alignment device 130 may include a posterior arm 132, a swing arm 134, and an anterior arm 136. A lockable hinge 138 allows for relative planar rotation between the posterior arm 132 and the combination of the swing arm 134 and the anterior arm 136. The “closed” position of the hinge 138 is shown in
The posterior arm 132 and the anterior arm 136 each may have associated vacuum chambers 142, 146, respectively, for temporarily securing the positioning and alignment device 130 to the epicardial surface of the heart H. At a predetermined spacing from the posterior vacuum chamber 142, an indicator ball 150 may be connected thereto by a fixed dual-arm member 148. The anterior arm 136 may contain a tube defining a lumen for passage of the needle delivery assembly 110 therethrough. The anterior arm 136 and the posterior arm 132 each may have an associated vacuum lumen (not visible) extending therethrough in fluid communication with their respective vacuum chambers 146, 142. Associated fittings 156, 152 may be provided on the anterior arm 136 and the posterior arm 132, respectively, for connecting the corresponding vacuum lumens to a vacuum source (not shown).
With reference to
With reference to
In
With reference to
The posterior vacuum chamber 142 may include a retainer mechanism. For example, a capture plate 180 may be connected to a rotating insert 182 by connector pins 181. The capture plate 180 and rotating insert 182 are collectively captured between the base cover 178 and a capture plate cover 184, which is secured to the base cover 178 by screws 185. The capture plate 180 and rotating insert 182 are collectively rotatable relative to the base cover 178 and a capture plate cover 184.
The capture plate cover 184 defines an offset opening 186 into which the upper portion of the rotating insert 182 is positioned. The capture plate cover 184 also defines a semi-conical concave slope 188. Similarly, the rotating insert 182 defines a plurality of semi-conical concave slopes 190 that may be individually aligned with the slope 188 on the capture plate cover 184 by indexing (rotating) the rotating insert 182 relative to the capture plate cover 184 such that the semi-conical concave slopes 188, 190 collectively define a conical funnel that serves to guide the needle assembly 110 into the desired dock 192. Thus, if a needle assembly 110 is initially deployed in a first (center) dock 192, and it is desired to re-deploy another needle assembly 110, the rotating insert 182 and capture plate 180 may be collectively rotated relative to the capture plate cover 184 to align a second (auxiliary) dock 192 and its associated semi-conical slope 190 with the semi-conical slope 188 of the capture plate cover 184.
As seen in
As the bullet-shaped tip 124 of the needle assembly 110 is advanced into the posterior vacuum chamber 142, it is guided to a central dock 192 by the funnel collectively defined by slopes 188, 190. As the bullet-shaped tip 124 is advanced further into hole 196, the tabs 194 are resiliently deflected away. After the bullet-shaped tip 124 passes the tabs 194 and the distal end thereof is stopped by base cover 178, the tabs 194 resiliently spring back into the detent space 126 of the tip assembly 122, serving to lock the position of the tip assembly 122 and guide tube 120 relative to the posterior vacuum chamber 142.
Those skilled in the art will recognize that the positioning and alignment device 130 may be formed of a variety of materials and may have a variety of dimensions depending on, for example, the conditions of use and anatomical variability. By way of example, not limitation, the posterior arm 132, swing arm 134 and anterior arm 136 may be formed of stainless steel tubing. The connective elements (pins, screws, etc.) may also be formed of stainless steel. The rims 162, 172 of the anterior and posterior vacuum chambers 146, 142, respectively, may be formed of clear polycarbonate, or other similar suitable material, to facilitate visualization of the epicardial surface thereunder. The dual-arm 148 and the indicator ball 150 may be formed of PEEK with a stainless steel core wire running therethrough. The remaining components of the positioning and alignment device 130 may be formed of a polymeric material such as acetyl available under the trade name Delrin™. The vacuum lines connecting the fittings 152/156 to a vacuum source may comprises polyether block amide tubes with stainless steel coil windings therein. Other suitable materials may be used and are contemplated as being within the scope of the disclosure.
Also by way of example, not limitation, the posterior arm 132 may have a length of approximately 18 cm, the swing arm 134 may have a length of approximately 10 cm, and the anterior arm may have a length to accommodate approximately 5 cm to 13 cm of adjustable distance between the anterior vacuum chamber 146 and the posterior vacuum chamber 142. These exemplary dimensions have been found to accommodate a wide variety of anatomical sizes and variations. The needle assembly 110 may have a length of approximately 46 cm to traverse the heart H and provide sufficient length and flexibility for manipulation around the heart. The anterior vacuum chamber 146 and the posterior vacuum chamber 142 may have outside diameters of approximately 2 cm to provide adequate yet atraumatic holding power on the epicardium. Other suitable dimensions may be selected depending on a patient's particular anatomy, for example.
In use, the positioning and alignment device 130 is initially in the open position. The posterior arm 132 may be positioned through a thoracotomy (e.g. a median sternotomy), along the posterior aspect of the heart H and generally aligned with the long axis of the left ventricle LV. The indicator ball 150 may be positioned in the AV groove, by visual or tactile cues, or a combination of such cues. During this procedure, the heart H may be manipulated to facilitate direct visualization. The predetermined distance between the indicator ball 150 and the posterior vacuum chamber 142 places the vacuum chamber 142 in a desired position relative to the annulus AN of the mitral valve MV. The posterior vacuum chamber 142 is activated by applying a vacuum thereto, securing the chamber 142 to the epicardial wall is the desired position. The center of the posterior vacuum chamber 142 now corresponds to the future location of the intersection of the tension member 12 with the left ventricular LV chamber wall.
Assessment of the position of the posterior vacuum chamber 142 relative to internal mitral valve MV structures such as leaflets AL, PL, papillary muscles PM, and regurgitant jet may be performed with ultrasonic imaging such as trans-esophageal or epicardial echocardiography. The position of the posterior vacuum chamber 142 may be visualized on the echocardiogram by observing the portion of the left ventricular free wall LVFW that is less dynamic than the remaining portions thereof, rendered so by the dampening effect of the posterior vacuum chamber 142 fixed thereto. Mechanical manipulation of the positioning and alignment device 130 may also be performed to assess the functional impact of this position on the mitral valve regurgitation, as the heart is still beating. For example, the positioning and alignment device 130 may be pivoted about the posterior vacuum chamber 142 to drive the indicator ball 150 into the AV groove, thereby exerting an inward force on the annulus AN of the mitral valve MV. If the position is not optimal, the vacuum may be de-activated, and the posterior vacuum chamber 142 may be repositioned as desired. Conveniently, the posterior vacuum chamber 142 will leave a pucker mark on the epicardium at the initial position thereof, which may serve as a reference mark for repositioning.
The anterior arm 136, initially disconnected from the swing arm 134, is then manipulated to position the anterior vacuum chamber 146 on the epicardial surface of the heart, corresponding to the subsequent desired position of the anterior anchor pad 14. As the anterior arm is manipulated, echocardiographic information pertaining to the right ventricle RV and nearby tricuspid valve TV may be assessed and utilized to help find a desired position for the anterior vacuum chamber 146. Once in a desired position, the anterior vacuum chamber 146 is activated by application of vacuum, temporarily securing anterior vacuum chamber 146 to the epicardial surface of the heart. The swing arm 134 is then rotated into position to allow for the securing clamp 144 to clamp onto the anterior arm 136. The anterior arm 136 preferably is long enough (e.g., 5 to 15 cm) to allow for significant variations in heart diameters from patient to patient.
Both vacuum chambers 142, 146 are now securely positioned on the epicardial surface of the heart, in positions which will correspond to the anterior and posterior anchor pads 14, 16. The needle delivery assembly 110 now may be inserted through the passage lumen provided in the anterior arm 136, through the anterior vacuum chamber 146, across the heart and into the posterior vacuum chamber 142. The positioning and alignment device 130, with the needle delivery assembly 110 fully inserted through the heart chamber, is illustrated in
As the needle delivery assembly 110 is passed into the posterior vacuum chamber 142, the circumferential detent 126 on the tip assembly 122 engages with the retention mechanism of the posterior vacuum chamber 142. Once the needle delivery assembly 110 is locked in position in the central dock 192, the cap 116 and base 114 are pulled proximally from the anterior arm 136, thus removing the outer tube 112 and core member 118 from the needle delivery assembly 110. The tip assembly 122 and guide tube 120 are thus left in position across the heart chamber and define the path that will be taken by the tension member 12 through the heart H.
The vacuum to the anterior and posterior chambers 146, 142 may then be interrupted, allowing the positioning and aligning device 130 to be removed from the surface of the heart. As the positioning and aligning device 130 is removed from the heart, the tip assembly 122 and guide tube 120 remain engaged with the posterior vacuum chamber 142, bringing the tip assembly 122 and distal end of the guide tube 120 to an easily accessible location nearer the anterior side of the heart H. The tip assembly 122 may then be removed from the guide tube 120, such as by using a scissors, for example. The positioning and aligning device 130 is then removed from the surgical field, leaving only the guide tube 120 positioned across the heart chamber in the desired position for delivery of the mitral valve splint 10.
If necessary or desired, it is possible to reposition the guide tube 120. The positioning and aligning device 130 at this stage has the tip 122 from the prior needle delivery assembly 110 in the central dock 192. This tip 122 may be rotated out of position, bringing one of the auxiliary docks 192 into alignment with the slope 188 of the capture plate cover 184 as described hereinbefore. The positioning and aligning device 130 may then be repositioned on the heart H as described before, and a different needle delivery assembly 110 may then be delivered in a new position following the same steps described above.
Once the guide tube 120 is deemed in an appropriate position, the mitral valve splint 10 may be delivered in a manner similar to the method described in the U.S. application Ser. No. 09/680,435, now U.S. Pat. No. 6,723,038, filed Oct. 6, 2000, entitled METHODS AND DEVICES FOR IMPROVING MITRAL VALVE FUNCTION (hereinafter the '435 application), the entire disclosure of which is incorporated by reference. The tension member 12 is provided with the posterior (fixed) pad 16, or at least the block 42 of the releasable connection mechanism 40, connected thereto. The tension member 12 may include a leader section (not shown) that is advanced into the now accessible posterior (distal) end of the guide tube 120. Once the leader of the tension member 12 emerges from the anterior (proximal) end of the guide tube 120, the leader of the tension member 12 and the guide tube 120 are pulled proximally, placing the posterior anchor pad 16 in position on the epicardium. The anterior (adjustable) pad 14 is then positioned on the tension member 12. A measuring and tightening device such as that described in U.S. Pat. No. 6,260,552 to Mortier et al., the disclosure of which is incorporated herein by reference, may be used to adjust the spacing of the anterior and posterior pads 14, 16 to an optimum distance. Mitral valve function may be observed with appropriate diagnostic techniques such as transesophageal echocardiography (TEE) to assist in determining the appropriate distance between the anterior and posterior pads 14,16 and the appropriate tightness of the splint 10.
Once the splint 10 is appropriately tightened, the anterior pad 14 is secured to the tension member 12, similar to the method described in the '435 application, incorporated herein. At any time during delivery of the splint 10, the posterior pad 16 may be switched to a pad of a different shape or size, as described hereinbefore, by utilizing the releasable connection mechanism 40. Once the proper posterior pad 16 is in place and the desired mitral valve function is established and confirmed using an appropriate diagnostic method, the thoracotomy may be closed.
With reference to
A general difference between the septal approach illustrated in
To facilitate delivery of the septal splint 610, a balloon-tipped probe 620 may be utilized. The probe 620 may include an elongate shaft 622 having a length sufficient to extend across the right ventricle RV to the ventricular septum VS as shown in
In use, a guide tube (not shown in
A syringe (not shown) or other suitable inflation device may then be connected to the port 626 of the handle 624. The syringe may contain a curable inflation fluid such as, for example, a bone cement. The syringe may then be used to inflate the balloon 614 with the curable material as seen in
With reference to
To facilitate delivery of the self expanding septal pad 634, a delivery probe 630 may be utilized. Delivery probe 630 may include a barrel 632 defining a chamber therein which contains the self expanding septal pad 634 in a collapsed mode. A plunger 636 may extend into a proximal portion of the barrel 632. An expandable and sharpened tip 638 capable of penetrating the heart wall may be provided at the distal end of the barrel 632. Actuation of the plunger 636 in the distal direction with respect to the barrel 632 causes the self expanding septal pad 634 to be pushed into and through the tip 638, which may expand to accommodate the self expanding septal pad 634 therein.
In use, a guide tube similar to guide tube 120 (not shown) may be delivered across the right ventricle RV and left ventricle LV utilizing the delivery system 100 and related method described previously, but with a different orientation as compared to the orientation shown in
With reference to
As best seen in
In use, a guide catheter 820 may be navigated through a patient's vascular system until the distal end thereof resides within the right ventricle RV. For example, the guide catheter 820 may be navigated from the peripheral veins in the arm to the superior vena cava SVC, through the right atrium RA, past the tricuspid valve TV, and into the right ventricle RV. The distal end of the guide catheter 820 includes a curved portion 822 to direct the distal end of the guide catheter 820 at the ventricular septum VS. Once the guide catheter 820 is in this position, a guide wire 830 may be inserted through the guide catheter 820. A tissue penetrating tip (e.g., sharpened tip) 832 of the guide wire 830 may pass through the ventricular septum VS, across the left ventricle LV, and through the left ventricular free wall LVFW as shown in
A balloon-tipped catheter 840 may then be passed over the guide wire 830 as shown in
The balloon catheter 840 may then be urged distally over the guide wire 830 until the balloon traverses the left ventricular free wall LVFW as shown in
Using the tension member 812 as a substitute for the guide wire 830, another balloon-tipped catheter 850 may then be passed over the tension member 812. The balloon catheter 850 is similar to balloon catheter 840, except that balloon 814 may be secured to the tension member 812 upon curing. The second balloon catheter 850 may be urged distally until the balloon 814 engages the ventricular septum VS is inflated with a curable material. With the posterior balloon 816 in the desired location and the distal end of the tension member 812 fixed thereto, the tension member 812 may be pulled proximally while pushing on the second balloon catheter 850 to force the leaflets AL, PL into full apposition as shown in
With reference to
Self expanding pad 900 includes a first arm 902 and a second arm 904 that pivot at their midpoints. The tension member 12 is fixedly connected to the first arm 902 and extends through a central hole in the second arm 904, thus pivotally connecting the two arms 902, 904. Two spring members 906, 908 are connected to the ends of the first and second arms 902, 904 as shown, to provide a biasing force on the arms 902, 904 rendering them self-expandable. The two spring members 906, 908 may be formed of spring tempered stainless steel, for example, or other suitable material. The first arm 902 and the second arm 904 may be formed of a stainless steel hypotube stock, for example, or other suitable material.
The first arm 902 may have a circular cross-section and the second arm 904 may be crimped to define a c-shaped or u-shaped cross-section. With this geometry, the first arm 902 rests in the second arm 904 (in the collapsed configuration) to create a toggle between the collapsed configuration and the expanded configuration. The first arm 902 defines a central recess 922 (visible in
As shown in
As shown in
With reference to
The catheter shaft 1012 includes an outer tube 1014 to which the proximal end of the balloon 1002 is bonded and sealed. The catheter shaft 1012 also includes an inner tube 1018 disposed in the outer tube 1014 which defines an inflation lumen extending therethrough in fluid communication with the interior of the balloon 1002. The shaft 1012 may include a braid reinforcement 1016 carried in or under the outer tube 1014 to provide the same properties as the tension member 12. The braid reinforcement 1016 may comprise a continuation of the filaments 1004 extending from the balloon 1002. Alternatively, braid reinforcement 1016 may comprise a separate component and the proximal end of the filaments 1004 may be connected to the bond site between the balloon 1002 and outer tube 1014. If the braid reinforcement 1016 comprises a continuation of the filaments 1004 extending from the balloon 1002, the filaments 1004 forming the braid may extend coaxially around the inner tube 1018 as shown in
A syringe (not shown) or other inflation device may be connected to the proximal end (not shown) of the shaft 1012 to communicate with the inflation lumen of the inner tube 1018. The syringe may contain a curable inflation fluid such as bone cement. The syringe may then be used to inflate the balloon 1002 with the curable material as seen in
In yet another embodiment, a device for improving the function of a heart is provided. The device may include an elongate member for drawing at least two walls of the heart toward each other to reduce the radius or area of one or more heart chambers in at least one cross sectional plane. The elongate member may have an anchoring member disposed at opposite ends for engagement with the heart or chamber wall. Further, the elongate member may be configured to store contractile energy exerted by a heart chamber during, e.g., systole and release the stored energy during diastole to assist the heart chamber in expansion during, e.g., diastole. The elongate member may include a spring or spring like portion which compresses during systole to store energy, and releases the stored energy to help the elongate member to return to an uncompressed state, thereby assisting the chamber of the heart to expand during diastole.
Turning now to
As shown in
Further, a plurality of devices 1100 may be implanted on heart H. In one such embodiment, a first device 1100 may be implanted across the left ventricle LV, and a second device 1100 may be implanted across the right ventricle RV. In another embodiment, one or more devices 1100 may be implanted across a single heart chamber. Further, the use of device 1100 may not be limited to a heart's ventricles. Indeed, device 1100 may be positioned to traverse one or both of a heart's atria.
In the embodiment depicted in
In some embodiments, elongate member 1102 may be constructed from suitable biocompatible materials having elastic properties so that elongate member 1102 may have the elastic characteristics. Such materials may include, but are not limited to, nickel-titanium alloys, nickel-cobalt alloys, other cobalt alloys, thermoset plastics, thermoplastics, stainless steel, suitable shape-memory materials, suitable super-elastic materials, or combinations thereof, and the like. In other embodiments, elongate member 1102 may include a spring or spring-like portion 1112. Portion 1112 may include any suitable configuration known in the art. For example, portion 1112 may include a helical extension spring or a coil spring.
In all instances, however, elongate member 1102 may be configured to act substantially as a spring when implanted on a patient's heart H. For example, elongate member 1102 may be configured to compress and elongate as heart H naturally beats during a cardiac cycle. Generally, elongate member 1102 may be configured to compress as portions of heart H exert compressive forces on device 1100, such as, for example, during systole. During such compression, portion 1112 of elongate member 1102 may be configured to store energy (e.g., potential energy), and release the stored energy to help elongate member 1102 return to an uncompressed state when the compressive forces exerted by the heart are removed, such as, for example, during diastole. As a consequence of returning to its uncompressed configuration, elongate member 1102 may serve to assist associated portions of heart H expand during, for example, diastole.
In the specific embodiment of
Although the embodiment depicted in
With continued reference to
The elasticity or stiffness of portion 1112 may be configured so that portion 1112 may compress when subjected to contractile forces of the left ventricle LV. Similarly, the elasticity or stiffness of portion 1112 may be configured so that portion 1112 may cause elongate member 1102 to exert expansive forces on the associated heart walls. The elasticity or stiffness of portion 1112 may be determined using Hooke's Law (F=kx, where F=force, k=spring constant (i.e., stiffness), and x=displacement).
With continued reference to
Device 3000 may be configured to traverse both the left ventricle LV and right ventricle RV, as shown in
Elongate member 3002 may include a left ventricular portion 3003a, a right ventricular portion 3003b, and a septal portion 3003c. Each of the left ventricular portion 3003a and right ventricular portion 3003b may include a spring or spring-like portion 3012a and 3012b. Portions 3012a and 3012b may be substantially similar to portion 1112 in functionality. In addition, each of portions 3012a and 3012b may be substantially similar in structure to portion 1112 in one or more ways. Device 3000 may also include force dispersion components 3008, 3010 that are similar to components 1108, 1110. Further, septal portion 3003c may include a section of elongate member 3002 having a reduced cross-section relative to, e.g., portions 3012a, 3012b, so as to minimize the size of opening 3013 in the ventricular septum VS. Furthermore, septal portion 3003c may be provided with a coating or covering configured to reduce irritation to the ventricular septum VS when portion 3003c moves relative to the ventricular septum VS. Although the embodiment of
In one embodiment, the anchoring members 4004, 4006 may be dumbbell shaped expandable anchoring member, with a distal end 4080′ and proximal end 4010′. The proximal end 4010′ rests on the epicardium, whereas the distal end 4008′ acts as a force dispersion member, similar to the pads 1108, 1110, 2008, 2010, 3008 and 3010.
With continued reference to
The devices described in connection with
Device 1100, 2000, 3000 may be utilized to treat a patient's heart H and/or otherwise improve the function of heart H. The following exemplary method will be described relative to device 1100, however, those of ordinary skill in the art will readily recognize that a similar method may be practiced with device 2000, 3000. In one exemplary embodiment, device 1100 may be delivered to a patient's heart H via a catheter (not shown) in substantially the same method as described in conjunction with
Once positioned, device 1100 may act as a spring to store potential energy when elongate member 1102 is compressed by the heart H during, e.g., systole. When the heart H expands during, e.g., diastole, and the compressive forces applied during systole are no longer present on elongate member 1102, elongate member 1102 may return to its uncompressed length by releasing the stored potential energy. In doing so, elongate member 1102 may apply outward forces to the heart walls via force dispersion components 1108, 1110 to assist the heart in expanding during diastole.
The methods disclosed herein may be performed by any suitable surgical technique known in the art, including, but not limited to, open surgery, minimally invasive or non-invasive surgery, endoscopically, percutaneously, and/or any combination thereof. In one embodiment, it is contemplated that the devices disclosed herein may be implanted within a patient via, for example, a minimally invasive surgical technique known as a thoractomy, such as, for example, an eight (8) centimeter thoractomy. In other embodiments, the embodiments described herein may be implanted within a patient's heart via a transapical procedure. In further embodiments, the depicted embodiments may be delivered via catheter-based techniques, including those techniques previously discussed herein. In addition, the methods described herein may be performed with or without the aid of cardiopulmonary bypass, as desired. For example, in one embodiment, the devices disclosed herein may be implanted and/or adjusted while heart function has been temporarily ceased and the patient is dependent upon cardiopulmonary bypass (i.e., on-pump). In another embodiment, however, the disclosed devices may be implanted and/or adjusted in accordance with the present disclosure without ceasing heart function (i.e., off-pump).
Those skilled in the art will recognize that the present disclosure may be manifested in a variety of forms other than the specific embodiments described and contemplated herein. Accordingly, departures in form and detail may be made and the present disclosure is intended to cover modifications and variations.
The above description presents the best mode contemplated for carrying out the present method and device for heart treatment, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which they pertain to make this device and use these methods. This device and these methods are, however, susceptible to modifications and alternate constructions from those discussed above that are fully equivalent. Consequently, this system and these methods are not limited to the particular embodiments disclosed. On the contrary, this device and these methods cover all modifications and alternate constructions coming within the spirit and scope of the system and methods as generally expressed by the following claims, which particularly point out and distinctly claim the subject matter of the system and methods.
This application claims priority under 35 U.S.C. §119(e) (1) to the provisional patent Application No. 61/355,437 filed on Jun. 16, 2010, entitled “Devices and Methods for Heart Treatment”, the disclosure of which is incorporated herein by reference in its entirety.
Number | Date | Country | |
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61355437 | Jun 2010 | US |