Patent ID: 12251127

DETAILED DESCRIPTION OF THE INVENTION

The illustrations described herein are examples of the invention. Because of the scope of the invention, it is specifically contemplated that combinations of aspects of specific embodiments or combinations of the specific embodiments themselves are within the scope of this disclosure.

As noted above, the methods described herein increase a volume of a chamber of a heart to improve blood flow in diastolic heart failure. For example, incisions, cuts, holes, or other separation of tissue can be made in muscle forming the wall of the left ventricle to improve a diastolic function of the heart. Although the description and claims described herein discuss primarily treatments occurring in a left ventricle, unless specifically discussed or claimed, the treatments can occur in any chamber of the heart (e.g., the atriums and/or ventricles). Typically, access to the chambers of the heart (endocardium) can be made percutaneously or via a transapical approach. Once in the ventricle, small cuts, holes, or a combination thereof are made to the cardiac muscle at one or more layers of the musculature.

One of the goals of the therapeutic damage is to increase volume in these hyperdynamic hearts to allow improved physiology and ventricular filling and to reduce diastolic filling pressure by making the ventricle less stiff. In some cases, the type of therapeutic damage, e.g., angles, dimensions, length, depth, density, and architecture shall balance of the integrity of the musculature versus the functional result. Meaning the amount of therapeutic damage to the tissue must be balanced against compromising the integrity of the tissue. In many cases, the treatment can be optimized to ensure adequate function physiologically, hemodynamically, and electrophysiologically. Unless otherwise specified, the therapeutic treatments only extend into one or more layers of the cardiac muscle and not through the wall of the heart.

The therapeutic damage caused to the cardiac muscle can be additionally treated with agents that prevent closure of the wounds. Such agents can include pyrolitic carbon, titanium-nitride-oxide, taxanes, fibrinogen, collagen, thrombin, phosphorylcholine, heparin, rapamycin, radioactive 188Re and 32P, silver nitrate, dactinomycin, sirolimus, everolimus, Abt-578, tacrolimus, camptothecin, etoposide, vincristine, mitomycin, fluorouracil, or cell adhesion peptides. Taxanes include, for example, paclitaxel, 10-deacetyltaxol, 7-epi-10-deacetyltaxol, 7-xylosyl-10-deacetyltaxol, 7-epi-taxol, cephalomannine, baccatin III, baccatin V, 10-deacetylbaccatin III, 7-epi-10-deacetylbaccatin III, docetaxel. Other agents that could effect improved function include bioactive substances including proteins and cells like stem cells.

FIGS.1A and1B, illustrate respective top and side views of a first example of a treatment device100that can be used to make incisions in soft tissue according to the present disclosure. As shown, the device includes a handle102comprising a handle body104and an actuating member106. Variations of the device can include handles of any number of configurations. Typically, such variations include an actuating member that is moveable relative to a handle body. Such examples can include triggers, levers, dials, etc. Furthermore, the actuating portion can include a switch type mechanism in the event the respective variation is driven by a motor or other automated means.

The device100further includes a flexible shaft110that extends between a near end112and a far end114. In the illustrated example, the near end112depicted as having an optional stress relief sleeve as well as a fluid port116for administering fluid through the device100. The devices can also include an optional source of current for coupling to electrodes on the device100(as described below), for pacing the soft tissue, monitoring EKG, determining whether the device's cutting member is embedded within tissue, electrocautery, coagulation and/or electrodeposition of medicines or other substances. Similarly, the device100can include one or more sources of fluid134for coupling to the device100via a fluid port116. The fluid can be dispensed through the cutting member opening124or through a separate opening.

Variations of the device100can also include an atraumatic tip120that can optionally selected to be radiopaque. Alternatively, or in combination cutting element can be radio-dense so it is visible and its position can be determined during use. The example depicted inFIGS.1A and1Bincludes an atraumatic tip having the shape of a curved elastic member. In those cases, where the device100is used in the heart or other cavity the atraumatic curved member120protects the tissue from being punctured by the tip of the device120. The elastic curved member120also is able to flex and relax when pushed into the apex of the heart or cavity. In those variations where the flexed tip120is radiopaque, a physician performing the procedure will be able to observe the shape change of the tip under fluoroscopic imaging. When physician then actuates the device to cut tissue, the elastic property of the tip120pushes far end114of the device against tissue and assists in keeping the cutting element or member within the soft tissue while the cut is being made. Such a feature is especially useful when cutting heart tissue and the heart muscle is contracted during systole. Optionally, the device120can augment the process by pacing of tissue using electrical impulses.

FIG.2Aillustrates perspective partial cross-sectional view of a far end114of the device100ofFIGS.1A and1B. In this example, the far end114of the flexible shaft includes a relatively rigid section122coupled to the shaft110. The rigid section122carries a cutting member140that is secured to the rigid section122using a pivot member144. The cutting member140depicted is for illustration purposes only. Any number of blade shapes can be employed in addition or in combination with the illustrated cutting member. The cutting member140is also coupled to a link member148at a connection point150. The link member148extends through the shaft110and is secured to the actuating member106discussed above. The link148, a wire in the illustrated example, can include additional components to assist in applying a tensile force to the cutting member140. In the illustrated example, the link member148includes an inner tube152and an outer tube154that are located within a passage118of the flexible shaft110. Such components can improve the structural integrity of the link148or can serve to insulate and/or separate the link148from electrical components (not illustrated) extending through the passage118. The passage can also include a valve either in the shaft and/or in the handle to prevent back bleeding into the catheter. A channel for a guide wire can also be used.

FIG.2Billustrates a partial side view of the device100discussed above, as shown the link148is secured to the actuating member106(shown inFIGS.1A and1B) such that upon application of a tensile force, the link member148causes movement of the cutting member140. However, prior to actuation, the cutting member140is retained within the device100so that the cutting surface14is shielded and cannot inadvertently cut tissue. Variations of the device can also include additional features160can be coupled to the cutting member140and/or the link148such as a strain gauge, spring, or similar structures that allow either retention of the cutting member within the device100or monitoring of the cutting member140as it cuts tissue. As illustrated, a variation of the device100includes a cutting member140having a link connection point150that is offset from an axis A-A of an area of the device100immediately surrounding the cutting member. This eccentric configuration improves actuation of the cutting member and can cause the far end of the device100to preferentially apply a force toward a lateral side of the device where the cutting edge142is eventually exposed. Such a feature can increase the ability and ease of which the physician can push the cutting edge142into the heart muscle. In additional variations, the entire cutting assembly140(including the pivot point144) is offset from the axis towards the lateral side of the device100.

FIG.2Balso illustrates an optional sheath164or cover that can be slidably mounted on the flexible shaft110. During advancement or positioning of the device, the sheath164can be advanced over the opening124to prevent the cutting member140from inadvertently damaging tissue. Moreover, the sheath164can function as an added safety measure since distal movement (in the direction of arrows166can separate the cutting member from tissue or can push the cutting member back into the device100if the link148fails.

FIG.2Cillustrates a proximal or tensile force162applied to the link148causing the cutting member140to pivot out of the opening124towards a lateral side of the device100. In the illustrated variation, the cutting edge142is exposed in a rearward direction so that pulling on the device100allows the cutting member140to cut tissue when the cutting member is advanced adjacent to or positioned within tissue. As noted above, the main passage118of the device (or any additional lumen or fluid supply tube) can be used to deliver any number of fluids or substances to an opening in the device, including but not limited to the cutting member opening124.

In alternate variations, the cutting member140includes cutting edges142on the front side or on both sides of the cutting member140to allow rearward and forward cutting.FIG.2Calso illustrates the link148being eccentric in relation to an axis of the device. This feature results in a lateral force component as noted by arrows168. The lateral force component168is directed towards the lateral side of the device and assists in maintaining the cutting member140within tissue during cutting. As noted above the lateral force causes the catheter to differentially bend or urges the far end of the device100toward the blade side (lateral side), increasing the ability to push the blade into the heart muscle or other soft tissue. Additional variations of the device do not rely upon eccentric placement of the cutting member or link but create a lateral force through adjustment of the blade configuration. In addition, variations of the device include a pivot144that is located distally to the link attachment point146when the cutting member140is exposed. As shown inFIG.2C, the link attachment point146is proximally located relative to the pivot144. This configuration prevents interference between the link148and the pivot144of the cutting member140and allows the link to apply lateral force to the far end of the device so that the device flexes in the direction of the cutting member140.

As noted above, a variation of the device100can include the cutting member140that is positioned within a rigid section122that is adjacent to the flexible shaft110. The rigid section prevents deflection of the area adjacent to the cutting member opening124, which allows for greater control of the amount of exposure of the cutting edge.

FIG.3Aillustrates a variation of the device where the rigid section122comprises an enclosure that is secured to a distal end of the flexible shaft110. The enclosure122can comprise a conductive material so that it can be used to apply energy, pace tissue, or sense for contact with tissue. In such a case, the enclosure can be electrically coupled to a power supply130via known means136. Alternatively, the enclosure can comprise an insulated or non-conductive structure but still selected to maintain rigidity as described above.

Alternatively, or in combination, the cutting member140can be selected from a conductive material and electrically coupled to a power supply138via known means. In additional variations, the cutting member140can be fabricated from a non-conducting material or insulative material (e.g., ceramic, polymer, a composite material). In the latter case, the cutting member140can optionally include one or more electrodes or energy transfer surfaces that are affixed or positioned on one or both sides of the cutting member140.

In an additional variation, as shown inFIG.3B, the flexible shaft110can house the cutting member140. In such a case, a reinforcement member168(either external or internal to the shaft110) can be coupled to the flexible shaft110where the reinforcement member renders the area as a rigid section.

FIG.3Balso illustrates a variation of the device where the flexible shaft110includes one or more electrodes170,172on an exterior of the shaft110and adjacent to the opening124. As shown, the electrodes can be coupled to a power supply using known means. The electrode configuration can be employed on the enclosure shown inFIG.3Aas well.

FIG.4Aillustrates an example of a treatment device as described herein being used in a chamber of the heart9. Clearly, the device100can be used in any pocket or cavity of soft tissue. As illustrated, a physician advances a treatment device100into a chamber8of the heart9. Once inside the chamber8, in this example the left ventricle, the physician can advance an atraumatic tip120of the device100against tissue (in this case the apex of the chamber) to provide an opposing force to allow penetration of the cutting member into cardiac tissue. Because the atraumatic tip120is elastic and resilient there is a reduced risk that the tip120will create undesired injury. In addition, the flexible shaft of the device100can include any number of reinforcing member126such as braids, coils, polymer coextrusion, etc., that maintains torqueability and/or column strength of the flexible member. Such characteristics are required for accurate placement of the cutting element against the desired area of tissue. As noted above, electrodes (or components of the device) can be used with a power supply130to assist in placement of the device, and/or provide therapeutic treatment. In some variations the device can be configured as a bi-polar device, with electrodes of opposite polarity on the device. Alternatively, the device can function in a monopolar or unipolar configuration. In such a case an external electrode131can be positioned on a remote area of the patient's body.

FIG.4Bshows a magnified view of the device100being advanced into position at the apex of the heart where deformation of the atraumatic tip120applies a force in a lateral direction168. As noted above, the atraumatic tip120is not limited to a curved configuration; instead, any shape that delivers a biasing force can be employed. Furthermore, some variations of the device may not require a biasing force applied by the tip.

FIG.4Balso illustrates advancement of the cutting member140to the lateral side. As noted above, this action can also apply a lateral force to assist in placement of the cutting element140within tissue. As shown inFIG.4C, The lateral force can assist retention of the cutting element140as it is withdrawn in a proximal or rearward direction leaving the therapeutic cut4in tissue. As noted above, a strain gauge or other structure can be used to measure the drag or resistance on the device to assist in determining whether the cutting element is engaged in tissue. In any case, as noted above, tension applied by the link not only actuates the cutting member, but also, when positioned in an eccentric location within the shaft, the tension also causes the catheter to differentially bend toward the blade side, increasing the ability to push the blade into the heart muscle.

Again, the shape of the blade or cutting member can be selected so that it stays in tissue while being pulled. In certain variations, the cutting member opens from distal to proximal direction so that it can be safely closed by retracting into the device sheath or by pushing a sheath over the cutting member.

The cutting element can be an electrically insulated blade (e.g., made of ceramic, polymers, or a composite structure) that allows electrodes on both sides of blade to be electrically isolated from each other. Electrodes can be used to monitor EKG for a current of injury to demonstrate cutting, can be used to pace the heart, demonstrating that the blade is within the heart muscle, and for other uses (electrocautery, depth measurement, electrodeposition of drugs/chemicals). If the cutting element is fabricated from a conductive material, it can be used for pacing, which allows a cut to be made during systole and pushes muscle onto blade for cutting. Alternatively, or in combination, the rigid section of the device can be used as a return electrode for sensing, treatment or manipulation of tissue as discussed above.

As noted above, the depth of cut can be varied by making the blade longer or shorter using the adjustments and stops discussed above. It can also be varied in a given-length blade catheter by exposing more or less blade with the angle of exposure varying from barely out of the catheter to 90 degrees from the long axis of the catheter.

The handle shown inFIGS.1A and1Bcan be ergonomic and allow the cutting element to be exposed by flexing the fingers of the operator's hand, and retracted by extending the fingers. The stop, as discussed above, can be placed on the handle so that the maximum blade exposure can be limited to a preset angle, corresponding to a preset depth. Electrical components can be connected at the handle which is electrically connected to the blade through the pull wire.

In many variations, the tip or cutting edge of the cutting member is sharp enough to allow the heart muscle (or other soft tissue) to be stabbed and the angle between the dull and sharpened side is acute enough to allow cutting with minimal force. An alternative sickle-shape is also possible, which causes the blade to remain within the tissue while being pulled but requires the knife to be pushed backward after the cut to disengage the tissue.

The device can also employ a pull-apart or splittable cover that retains the curved atraumatic tip temporarily straight to allow for easy entry into a guiding sheath during use. When this pull-apart cover is pulled off, the curled tip bends once it is unconstrained by the guiding sheath. This makes for ease of use, but also ensures single-use.

The diameter of the catheter does not constrain the length of blade or depth of cut as the width of the blade can be reduced to fit within even a small catheter. The length of the blade can therefore be several times the diameter of the catheter. For example, in one example the diameter of the device was 7 French, allowing it to go through the smallest of guide catheters known.

FIGS.5A and5Billustrate an additional variation of a medical device100configured to perform the procedures discussed herein. In this example, the medical device100includes features useful to direct the cutting element (not shown) against a wall of tissue when the opening into the cavity or heart is offset from the wall of tissue. As shown, the device100can include an offset180or bend that positions a cutting side of the device away from an axis of the proximal portion of the shaft110. The offset180can be shape set or activated/actuatable. The illustrated device100ofFIG.5Acan also optionally include one or more strut members182that further provide a biasing force on a side of the device100opposite to the cutting member.FIG.5Billustrates a variation of the device100including three struts182. The devices described herein can include any number of struts182where the struts can be located circumferentially away from the cutting member to provide a biasing force against an opposing wall of tissue, such that the opposing force assist in maintaining the cutting element within tissue.

FIG.5Cillustrates a variation of a strut182assembly that is positionable in the shaft of the device at the working end/far end. In use, the first end184is moveable relative to the second end186to permit outward flaring or deflection of the struts182. In addition, the end168of the strut can include features to improve bonding of the strut assembly to the shaft of the device.

FIGS.6A and6Billustrate another variation of a device for use as described herein, where the device includes orientation features to ensure positioning of the cutting side/opening192with respect to the device. As shown inFIG.6A, the cutting assembly can include a cutting member140coupled to a shaft196where a distal portion of the cutting assembly includes an alignment feature188. As shown inFIG.6B, the cutting assembly is advanced within a shaft110of the device to permit actuation of the cutting member140. The alignment feature188of the cutting assembly can be configured to nest against an alignment feature190of the device. In the illustrated variation, the alignment feature of the device190is positioned on the flexible tip120, however, any number of alignment features are within the scope of this disclosure as long as the alignment feature(s) permit registration/orientation of the cutting element to a pre-determined side of the device. The illustrated example also permits continued closing movement of the alignment features188and190to naturally bias the orientation of the cutting assembly towards the desired orientation.

One added benefit of such a configuration is that the length of the cutting shaft196can be marked or have a specific length such that the user can observe the proximal end of the cutting shaft196in relation to a proximal end of the device or shaft110to identify or confirm that the alignment features188and190are properly nested together.

FIGS.6A and6Balso illustrate a variation of the cutting element140coupled to a base196that includes pins144that ride in slots194of the cutting assembly. Where relative motion between the cutting shaft196and the shaft110of the device permits actuation of the knife.

The methods described herein can be performed using a number of additional modes to determine proper placement. For example, the methods can be performed under fluoroscopy and/or with contrast agents. Alternatively, or in combination, a device can include a pressure sensing tip or along catheter at one or multiple points that determine when the device is positioned against the heart wall. In another variation, the device can include an opening at the distal end that is attached to arterial sensing equipment. Next, the waveform of a pressure wave is observed. When the hole is covered by tissue, the tissue blunts the waveform. This effect can be used as a test for catheter wall apposition. A physician can also confirm placement using an echocardiogram (TTE, TEE, intracardiac) where image shows position of device relative to wall/tissue.

Current can also be used to determine blade contact with tissue. For example, a current can be placed through the tissue (through ekg or similar type electrochemical sensing). As the blade touches the tissue, a voltage change can be measured from the circuit completed by the blade's contact with tissue.

Additionally, implantable hardware within, near, or around these cuts/holes with drug eluting capability may be part of this procedure. As well, the hardware (knife or otherwise) used to make the intervention on the cardiac chambers may be coated with drugs much like in drug coated balloon angioplasty.

As noted herein, the physician can create one or more therapeutic incisions, cuts, cores, holes, or other similar therapeutic damage to increase volume in the ventricle when in diastole. As noted above, this damage reduces the stiffness of the ventricle (or cardiac muscle in the wall) to improve ventricular filling and reduce diastolic filling pressure (which resists blood flow into the ventricle). The method includes making one or more therapeutic damage sites within one or more chambers of the heart. In this variation, the treatments occur in the endocardium2. Any of the treatment devices3described herein can include spring biasing, steering, a steerable sheath or catheter, a pull wire, or other mechanism to assist in navigation or apposition of the working end4of the device3against the target site.

Devices for use in the methods described herein can incorporate alternative design options to improve safety to critical structures and to ensure cuts are made as expected (any combination or singular use of the below may be incorporated with any of the variations of the methods or devices discussed herein.)

The devices described herein can be used in other applications as well. For example, devices have applications to make MAZE incisions by making multiple cuts in or around the pulmonary vein/s to interrupt conduction of atrial electrical activity. The devices and procedures can be used for commisurotomy, by cutting valve in various places including commissures to decrease valvular stenosis. The devices can be used for any and all cardiovascular structures that have undergone stenosis/sclerosis, such as renal arteries/pulmonary veins after RF exposure by cutting longitudinally with knife catheter. Furthermore, the devices can be used to perform plastys in all chambers of the heart by cutting longitudinally with the knife blade. Another potential use includes septal ablations by cutting longitudinally with the knife device; endarterectomy using the blade as cutting device to remove plaque. This peeling/cutting device will be proximal to a distal umbrella unit at the tip of the device that is used to both peel plaque and prevent embolization. Current open methods of carotid endarterectomy lead to stenosis secondary to opening the vessel and subsequently closing the incision; our method would provide an advantage over this as we would not be opening the vessel. Glaucomaplasty via Canal of Schlem incision thus increasing the diameter of the canal, increasing the flow of aqueous humor, and thus decreasing intraocular pressures. The devices can be used for tear duct plasty as well as looking for chronic sinusitis; third ventriculoplasty for obstructive hydrocephalus; and psialalithiasis intervention to remove stones.