Patent Application
20230414354
The present invention relates generally to annuloplasty rings, and in particular to an annuloplasty ring and tether adjustment system and methods of deployment and use.
In vertebrate animals, the heart is a hollow muscular organ having four pumping chambers: the left and right atria and the left and right ventricles, each provided with its own one-way valve. The natural heart valves are identified as the aortic, mitral (or bicuspid), tricuspid and pulmonary, and each has flexible leaflets that coapt against each other to prevent reverse flow.
With functional mitral regurgitation caused by ischemia or dilated cardiomyopathy, the mitral valve itself is normal, but regurgitation through a gap in the mitral valve occurs as a result of abnormal tethering forces caused by displacement of the papillary muscles due to enlargement of the left ventricle. Published estimates show that ischemic mitral regurgitation (IMR) occurs in 20-30% following a myocardial infarction. It has also been shown that severe mitral regurgitation is associated with a 3-fold increase in heart failure and a 1.6-fold increase in mortality at 5 years.
Various surgical techniques may be used to repair a diseased or damaged valve or heart muscle. A commonly used repair technique effective in treating incompetence is restrictive annuloplasty, which often involves reshaping or remodeling the annulus by attaching a prosthetic annuloplasty repair segment or ring thereto. A “remodeling” annuloplasty ring typically has an inner core that resists conforming to the native annulus shape and instead forces the annulus to conform to it. Remodeling annuloplasty bands or rings are “generally rigid” or “semi-rigid” in that they will resist distortion when subjected to the stress imparted thereon by the mitral valve annulus of an operating human heart. In this sense, “distortion” means substantial permanent deformation from a predetermined or manufactured shape (e.g., the ring or ring will tend to return to its preset shape in use). A typical remodeling annuloplasty ring comprises an inner substrate or core of a metal such as a rod or multiple bands of stainless steel or titanium covered with a biocompatible fabric or cloth and perhaps silicone to allow the ring to be sutured to the fibrous annulus tissue. The Physio® ring from Edwards Lifesciences of Irvine, CA is a closed “semi-rigid” ring because it offers selective flexibility at the posterior section while preserving the remodeling effect through a rigid anterior section. The newer Physio II® ring from Edwards Lifesciences also features up and down curves to better fit the nonplanar contours of the mitral annulus. Various other rings have posterior bows, e.g., U.S. Pat. Nos. 6,805,710 and 6,858,039, 7,959,673, or other three-dimensional configurations.
Other than revascularization, the treatment for ischemic mitral regurgitation remains controversial. Restrictive annuloplasty alone may alleviate the regurgitation in the short-term, but the long-term results are poor. This is due to continued expansion/remodeling of the ventricle, which is not addressed by simple reductive annuloplasty. As such, there has been a movement toward valve replacement in IMR patients; however, replacement in these patients has been shown to have higher perioperative mortality. The elimination of MR may be more durable in replacement patients as prosthetic valves are not affected by ventricular geometry, but long-term survival is still poor as the ventricle is not addressed and may continue to remodel to a more advanced stage of heart failure.
Work pioneered by Irving Kron and colleagues has shown that relocating/suspending the papillary muscles toward the mitral annulus using sutures, in conjunction with a non-restrictive annuloplasty, creates a durable and long-lasting repair. These methods have been widely studied and reported on by Kron and colleagues as well as many others, with promising results in terms of reduced MR reoccurrence and improved mortality. However, despite the very promising results using these seemingly simple techniques, they have not been widely adopted, perhaps because it is difficult to know how much to relocate the papillary muscles. As with all open mitral procedures, these methods are performed on an arrested, depressurized heart. As such, the geometry of the mitral valve, subvalvular apparatus, and ventricle, are all in a completely different state compared to when the heart is a pressurized, actively contracting organ.
Despite numerous therapeutic solutions presently available or proposed in the past, there is a need for a better repair procedure for mitral regurgitation caused by ischemia or dilated cardiomyopathy.
The present invention provides an annuloplasty ring and subvalvular attachment for repair of mitral and tricuspid valves experiencing regurgitation due to diseases of the heart muscle such as ischemia or cardiomyopathy. The repair involves implanting an annuloplasty ring at the annulus to which tethers are attached connected to subvalvular structures such as the papillary muscles. The annuloplasty ring and tether adjustment system incorporate features for papillary muscle relocation that can be implanted on-pump and adjusted off-pump for an optimal result. The repair is performed on an arrested heart, but then the final length and tension of the papillary muscle relocation tethers are fine-tuned and ultimately locked while the heart is beating. Visualization helps determine the optimal tether length.
In one embodiment, an annuloplasty ring for repair of mitral and tricuspid valves including an inner core covered by an outer suture-permeable interface. The inner core defines a closed peripheral shape surrounding an orifice and at least one outwardly-projecting boss configured to provide a suture anchor, such as having a pair of apertures. A plurality of anchoring sutures pass through the interface and secure the annuloplasty ring to a native heart valve annulus, while at least one tethering suture ties to the suture anchor and extends to attach to structure in a subvalvular chamber below the native heart valve annulus. The length of the tethering suture is adjusted while the heart is beating using a tensioning system to ensure proper valve functioning.
An exemplary annuloplasty ring and tether adjustment system comprises an annuloplasty ring including an inner core covered by an outer suture-permeable interface. The inner core defines a closed peripheral shape surrounding an orifice and the interface closely surrounds the inner core and has a matching shape. The inner core further defines at least one outwardly-projecting boss configured to provide a suture anchor. A plurality of anchoring sutures adapted to pass through the interface secure the annuloplasty ring to a native heart valve annulus. At least one tethering suture is configured to loop through subvalvular structure in a chamber below the native heart valve annulus and tie off thereto. The tethering suture has a length such that a pair of free ends extends from the subvalvular structure through the outwardly-projecting boss on the inner core and out of the body. A tether adjusting mechanism includes at least one tubular arm having a length sufficient to extend from the native heart valve annulus through an access incision in the heart and out of the body. The pair of free ends of the at least one tethering suture pass through the at least one tubular arm, and the pair of free ends has a first end and a second end. A tensioner receives the second end, and the at least one tubular arm has sufficient column strength such that tension on the second end caused by the tensioner decreases the distance between the subvalvular structure and the annuloplasty ring, at which point the first and second end are configured to tie off to the outwardly-projecting boss.
The exemplary annuloplasty ring and tether adjustment system preferably has at least two outwardly-projecting bosses spaced apart around the inner core, and in one embodiment there are three outwardly-projecting bosses spaced apart around the inner core, two of which are more closely spaced to each other than from a third. The suture-permeable interface may have a silicone inner portion surrounded by a fabric cover.
The annuloplasty ring may be adapted to be implanted at the mitral annulus, such that the inner core peripheral shape is a rounded D-shape with an anterior segment on a substantially straight side opposite a more curved posterior segment, and wherein the at least one outwardly-projecting boss is located in the posterior segment. The inner core may define a major axis across a long dimension perpendicular to a minor axis, wherein the anterior segment and the posterior segment are on opposite sides of the major axis, and wherein there are at least two outwardly-projecting bosses on opposite sides of the minor axis and located in the posterior segment. In one embodiment, there are only two outwardly-projecting bosses, one on each side of the minor axis and two tethering sutures.
In the annuloplasty ring and tether adjustment system, the tether adjusting mechanism may have a tubular arm for each tethering suture, and further include a common access sheath through which the tubular arms extend. The at least one outwardly-projecting boss may comprise a rounded rectangular projection through which a pair of identical apertures extend, or a T-shaped projection having rounded ends.
An exemplary annuloplasty ring and tether adjustment system disclosed herein comprises an annuloplasty ring including an inner core covered by an outer suture-permeable interface. The inner core defines a closed peripheral shape surrounding an orifice and the interface closely surrounds the inner core and has a matching shape. The inner core defines at least one outwardly-projecting boss configured to provide a suture anchor. A plurality of anchoring sutures are adapted to pass through the interface and secure the annuloplasty ring to a native heart valve annulus. Finally, at least one tethering suture is tied to the outwardly-projecting boss and has a length sufficient to extend from the outwardly-projecting boss to attach to structure in a subvalvular chamber below the native heart valve annulus.
There may be at least two outwardly-projecting bosses spaced apart around the inner core, and in one embodiment there are three outwardly-projecting bosses spaced apart around the inner core, two of which are more closely spaced to each other than from a third. The suture-permeable interface may comprise a silicone inner portion surrounded by a fabric cover. In one embodiment, the annuloplasty ring is adapted to be implanted at the mitral annulus, and the inner core peripheral shape is a rounded D-shape with an anterior segment on a substantially straight side opposite a more curved posterior segment, and wherein the at least one outwardly-projecting boss is located in the posterior segment. Furthermore, the inner core may define a major axis across a long dimension perpendicular to a minor axis, wherein the anterior segment and the posterior segment on opposite sides of the major axis, and wherein there are at least two outwardly-projecting bosses on opposite sides of the minor axis and located in the posterior segment. The at least one outwardly-projecting boss may comprise a rounded rectangular projection through which a pair of identical apertures extend, or a T-shaped projection having rounded ends.
A method for implanting an annuloplasty ring at a native heart valve annulus and adjusting subvalvular structure below the native heart valve annulus, comprises:
In the method, after the step of advancing the annuloplasty ring to the heart valve annulus, the method may include advancing a tubular arm down each pair of free ends of tethering sutures from outside the body until the tubular arm contacts the annuloplasty ring, and wherein the step of adjusting the tension on one of the free ends of the at least one tethering suture places the tubular arm in compression. There may be at least two outwardly-projecting bosses spaced apart around the inner core and at least two tethering sutures. The tubular arms may pass through a common access sheath, and the access incision is sealed around the common access sheath.
In the method, each pair of free ends may have a first end and a second end, and further including a tensioner that receives the second end, the at least one tubular arm having sufficient column strength such that tension on the second end caused by the tensioner decreases the distance between the subvalvular structure and the annuloplasty ring, at which point the first and second end are configured to tie off to the outwardly-projecting boss.
In the method, the at least one outwardly-projecting boss may comprise a rounded rectangular projection through which a pair of identical apertures extend, or a T-shaped projection having rounded ends.
All methods disclosed herein also encompass simulations of the methods, for example, for training; testing; demonstration; or device or procedure development. Methods for treating a patient can include simulating treatment on a simulated human or non-human patient, for example, an anthropomorphic ghost. Examples of suitable simulated patients can include both an entire body, any portion of a body, or at least a portion of an organ, for example, a heart. The simulations can be physical, virtual, or any combination thereof. Examples of physical simulations can include any combination of natural or manufactured whole human or animal cadavers, portions thereof, or cadaver organs. Virtual simulations can include any combination of virtual reality, projections onto a screen or on at least a portion of a physical simulation, or other in silico elements. Some simulations can include non-visual elements, for example, auditory, tactile, or olfactory stimuli.
A further understanding of the nature and advantages of the invention will become apparent by reference to the remaining portions of the specification and drawings.
Features and advantages of the present invention will become appreciated as the same become better understood with reference to the specification, claims, and appended drawings wherein:
The right ventricle RV and left ventricle LV are separated from the right atrium RA and left atrium LA, respectively, by the tricuspid valve TV and mitral valve MV; e.g., the atrioventricular valves. Though correction of the mitral annulus is the primary focus of the present application, it should be understood that certain characteristics of the annuloplasty rings described herein may equally be used to treat the tricuspid valve TV, and thus the claims should not be constrained to the mitral ring unless expressly limited.
The application discloses an annuloplasty ring that incorporates bosses for tying off sutures that can be placed through papillary muscles (PM), along with a tether adjustment system for tensioning the PM sutures on a beating heart. The ring and papillary muscle sutures would be implanted on an on-pump, arrested heart. The shaft of the tether adjustment system could be passed through a small opening in the wall of the atrium and sealed with purse-string sutures to form a hemostatic seal such that the heart can be weaned off bypass for final adjustment of the PM suture lengths.
The term “axis” in reference to the illustrated annuloplasty rings, and other non-circular or non-planar rings, refers to a line generally through the centroid of the ring periphery when viewed in plan view. “Axial” or the direction of the “axis” can also be viewed as being parallel to the average direction of blood flow within the valve orifice and thus within the ring when implanted therein. Stated another way, an implanted mitral ring orients about a central flow axis aligned along an average direction of blood flow through the mitral annulus from the left atrium to the left ventricle. The plan views of the annuloplasty rings illustrated herein are as looking from the atrial side in the direction of blood flow. For the purpose of orientation, therefore, the atrial side of the ring is up in the ventricular site is down.
The leaflets are shaped such that the line of coaptation resembles a smile that approximately parallels the posterior aspect of the mitral annulus MA. The anterior leaflet AL spans a smaller peripheral aspect around the mitral annulus MA than the posterior leaflet PL, but the anterior leaflet AL has a convex free edge that extends farther into the orifice defined by the mitral annulus MA. The posterior leaflet PL, on the other hand, has a generally concave free edge. Two commissures—an anterior commissure AC and a posterior commissure PC—generally defined the intersection of the line of coaptation between the two leaflets AL, PL and the mitral annulus MA. The posterior leaflet is divided into three scallops or cusps, sometimes identified as P1, P2, and P3, starting from the anterior commissure AC and continuing in a counterclockwise direction to the posterior commissure PC. Per convention, a major axis of the mitral annulus intersects both the first and third posterior scallops P1 and P3, approximately at the commissures AC, PC, and a minor axis intersects and generally bisects the middle posterior scallop P2. The anterior leaflet also features scallops or regions labeled A1, A2, and A3 as indicated in
As illustrated, the mitral annulus has a kidney or rounded D-shape around its periphery. The mitral anterior leaflet AL attaches to a somewhat straight anterior fibrous portion of the mitral annulus, which makes up about one-third of the total mitral annulus circumference. The anterior fibrous annulus, the two ends of which are called the fibrous left and right trigones LT, RT, forms part of the central fibrous skeleton of the heart. The arcuate muscular portion of the mitral annulus constitutes the remainder of the mitral annulus, and the posterior leaflet PL attaches thereto. The anterior commissure AC and the posterior commissure PC are located just posterior to each fibrous trigone.
The annuloplasty ring 30 may be three-dimensional with an upward bow in the posterior segment 32 as well as an upward bow in the anterior segment 34, as seen in
The suture-permeable interface may include an elastomeric sleeve 42 closely surrounding the core and a fabric outer cover (not shown), for example, a polyethylene terephthalate (PET) fabric cover. In the preferred embodiment the elastomeric sleeve 42, which may be silicone rubber, is generally tubular and molded to have a radially outwardly-extending flange 44 to facilitate suturing of the ring 30 to the mitral annulus. The ring 30 may be secured with sutures, staples, or other such devices to an inside fibrous ledge of the mitral annulus. In a typical procedure, the surgeon anchors an array of sutures through the annulus and then threads them through corresponding locations around the interface on the outside of the ring 30. The ring is parachuted down the suture array to be seated at the annulus before tying off the sutures.
As indicated in
Each of the inner cores 40 shown in
Each of the bosses 60, 62, 64 is formed by a generally rectangular projection with rounded corners and has two through holes or apertures 68 formed therein. The apertures 68 provide passageways for sutures when anchoring the annuloplasty ring 30 to subvalvular structures. A pair of separated apertures 68 enables the suture to be tied off and thus anchored to the ring. It should also be understood that rather than simple holes through the bosses, clamping structure may also be incorporated which enables anchoring of each of the tethering sutures without tying knots. For instance, SUTRAFIX® fasteners (Edwards Lifesciences, Irvine, California) could be deployed on the tethering sutures 72 relatively easily upon proper tensioning. Likewise, crush sleeves, cleats, wedges, screws, and other common mechanisms for securing two cords could be used. However, this would add some complexity and increase the cost of the device considerably.
The inner core 40a of
The fourth boss 66 is shown as a variation from the others. Namely, the boss 66 comprises an outwardly-directed T-shaped projection having rounded ends that curl back inward toward adjacent portions of the core 40d. Tethering sutures can be passed on both sides of the boss 66 and tied off, much like the pair of apertures formed in the other bosses 60, 62, 64. As such, all of the bosses 60, 62, 64, 66 are configured as suture anchors. Of course, other outwardly-directed structures that enable a suture to be tied off are contemplated, and the disclosure should not be considered limited to the illustrated embodiments.
The location of the outward bosses depends on how the ring 30 will be used to reshape the left ventricle, which in turn depends on the pathological condition. For example, for the ischemia illustrated in
Other researchers have relocated a single PM head on each side, and some have even only relocated a single PM. Likewise, there is some variation in where the sutures from the PM(s) are located on the annulus, with some investigators placing them closer to the fibrous trigones or commissures. As such, any number of bosses and any location of the bosses is possible and is not restricted to the examples shown here.
Subsequently,
The tether adjustment shaft 94 extends proximally and the three arms 84 diverge at some point and the individual tethering sutures 72 are then separated. The lumen for each arm 84 is separate from end to end to allow for independent routing, tensioning, and tying of each PM relocation suture 72.
One free end 72a of each pair of tethering sutures 72 remains slack, while the second free end 72b is held taut and passes through a tension adjuster 98. The dashed outline indicates a housing of some sort which maintains rigidity between each of the tension adjusters 98 and the arms 84 to allow the tension adjusters to increase or decrease tension on each of the tethering sutures 72 relative to their eventual point of anchor within the left ventricle. In the illustrated embodiment, the tension adjusters 98 have rotating dials which gradually adjust the tension on the corresponding suture, and a gauge 100 indicating the absolute tensile force on each may be used. Alternatively, the gauge 100 may be calibrated to indicate distance. Of course, sliders or other tension adjusters can be utilized. While the patient's heart is beating and the mitral valve is subjected to external visualization, such as fluoroscopy, tension on each of the tethering sutures 72 may be adjusted in coordination until regurgitation through the mitral valve is minimized.
Once each of the tethering sutures 72 has been secured to the proximal side of the annuloplasty ring 30, the sutures are severed close to the ring with a guillotine-type cutting mechanism or other cutting device. The tether adjustment system arms 84 are then removed from the body, as seen in
It should be understood that tethering the annuloplasty ring 30 to the papillary muscles PM is only one technique that can be used. In addition to the configuration shown, various other means of attachment to the PMs or heart wall are possible, such as helical anchors with sutures extending from them, for example, or anchors mounted to the exterior of the heart with sutures extending through the myocardium and toward the annulus. Simple pledgets on the exterior surface of the heart could also be used, or knots could be deployed on the outside of the heart with their sutures extending back into the heart toward the annulus. Other types of anchors not explicitly mentioned here should also be included. For instance, WO2020197854A1 to Passman, et al. discloses a number of ventricular anchors within or to the exterior of the heart muscle which could be utilized, and the Passman disclosure is expressly incorporated herein by reference.
Also, a modular approach to the delivery system could be used wherein the tension adjustment system tubes 84 and tension adjusters 98 are separate, rather than merging into a single tube and then splitting out again near the system handle. With separate systems, there would be more flexibility in how many PM relocation sutures were used. The system could, for example, come with enough for 4 sets of tubes with tension adjusters and the surgeon could decide how many they needed to use depending on the individual patient's anatomy. With 4 sets of tubes, for example, a single barrel-shaped component could be included that contained 4 hemostatic valves such that the tubes to be used could be passed through the valves, and then the barrel-shaped component could be used for hemostatic seal at the atrial wall with a purse-string, rather than a common tube as shown in the attached figures.
Likewise, various connections between the annuloplasty ring 30 and the PM suture tension tubes 84 are possible. A raised male feature could be part of each boss that mates with the end of the tube 84, potentially with a snap fit for security. A sleeve within each tube 84 could then “eject” the ring 30 at its connection when appropriate by, for example, pushing a control on the delivery system handle. Other connections such as threaded connections are possible. Since there is tension in the PM relocation sutures and, hence, compression between the tubes and ring core, a connection with a mechanical lock may not be necessary, however.
While the foregoing is a complete description of the preferred embodiments of the invention, various alternatives, modifications, and equivalents may be used. Moreover, it will be obvious that certain other modifications may be practiced within the scope of the appended claims.
This application is a continuation of International Patent Application No. PCT/US22/019176, filed Mar. 7, 2022, which claims the benefit of U.S. Patent Application No. 63/158,821, filed Mar. 9, 2021, the entire disclosures all of which are incorporated by reference for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| 63158821 | Mar 2021 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US22/19176 | Mar 2022 | US |
| Child | 18464232 | US |
