Tissue-laceration device

Abstract

A tissue-laceration device (22) includes an elongate shaft (24) and a tissue-stabilizing tool (30) including a proximal tubular portion (34), and two or more radially-expandable stabilizing legs (32) extending from the proximal tubular portion (34). The device (22) includes a cutting element-housing leg (40) coupled to the elongate shaft (24) and movable toward and away from each of the stabilizing legs (32) in order to trap tissue between the cutting element-housing leg (40) and each stabilizing leg (32). A retractable cutting element (51) is disposed within the cutting element-housing leg (40) and movable with respect to the cutting element-housing leg (40). One or more adjusting bars (54) coupled between the elongate shaft (24) and the cutting element-housing leg (40) facilitate movement of the cutting element-housing leg (40) toward and away from the stabilizing legs (32) and toward and away from the elongate shaft (24). Other embodiments are also described.

Description

[0001] TISSUE-LACERATION DEVICE

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority from US Provisional Patent Application 63 / 663,487 to lamberg er et al., filed June 24, 2024, and entitled "Tissue-laceration device," which is incorporated herein by reference.

[0004] FIELD OF THE INVENTION

[0005] Some applications of the present invention relate in general to tissue-laceration devices. More specifically, some applications of the present invention relate to treatment of native and prosthetic leaflets using the tissue-laceration device.

[0006] BACKGROUND

[0007] Transcatheter prosthetic valve replacement (or implantation) has been increasingly used as the preferred mode of treatment in several cardiac valve diseases. Large scale clinical trials have proven the value and the benefits of transcatheter aortic valve replacement (TAVR). Also, transcatheter aortic valve implantation inside a failed bioprosthetic aortic valve - also known as valve-in-valve (ViV) - has emerged as an alternative to redo surgery for patients at surgical risk. Despite the many advantages that ViV offers, coronary artery obstruction remains one common and life-threatening issue requiring careful pre-procedural planning. Recently, bioprosthetic or native aortic scallop intentional laceration to prevent iatrogenic coronary artery obstruction emerged as a solution to potential coronary obstruction (BASILICA). This procedure utilizes an electrocautery snare-and-slice technique to lacerate the existing bioprosthetic valve leaflets in front of the threatened coronary artery to prevent coronary obstruction or occlusion. The idea behind BASILICA technique is that the intentionally sliced leaflet spreads open after TAV deployment and forms a slot that introduces a new blood flow pathway towards the sinus from the neo-sinus and from the sinus to the coronary ostia, which otherwise may be occluded.

[0008] SUMMARY OF THE APPLICATION

[0009] For some applications, a tissue-laceration device is provided for lacerating or cutting tissue. The tissue-laceration device having a tissue-stabilizing tool and a cutting element-housing leg which comes in contact with tissue to be lacerated by the device. Typically, the tissue-laceration device is configured to lacerate leaflet tissue of a native valve or of a prosthetic valve. The tissue-laceration device is percutaneously deliverable to a native heart valve or to a prosthetic heart valve in a compressed state in which the tissue-stabilizing tool is in a compressed state, and is expandable at the native valve or at the prosthetic heart valve in order to grasp native leaflets of the native valve or prosthetic leaflets of the prosthetic valve. The tissue-laceration device is typically designated for use at a native or prosthetic aortic valve of a patient. It is to be noted that the scope of the present invention includes use of the tissue-laceration device at other native cardiac valves or other prosthetic valves implanted at the native valve of the patient, e.g., a pulmonary valve, a mitral valve, or a tricuspid valve.

[0010] A cutting element-housing leg coupled to the elongate shaft and movable toward and away from each one of the two or more radially-expandable stabilizing legs in order to move tissue and trap tissue between the cutting element-housing leg and each one of the two or more radially-expandable stabilizing legs. A retractable cutting element, e.g., a blade, is disposed within the cutting elementhousing leg and is disposed within a slit to enable movement of the cutting element along the slit in order to lacerate the tissue without movement of the remaining portions of the tissue-laceration device, i.e., without movement of the tissue-stabilizing tool or movement of the cutting element-housing leg and without movement of the distal portion of device 22 with respect to the tissue being lacerated.

[0011] The cutting element-housing leg is revolvable around the central longitudinal axis of the tissuelaceration device such that the cutting element-housing leg is positionable opposite each one of the two or more radially-expandable stabilizing legs. Typically, the tissue-laceration device has three radially-expandable legs.

[0012] For applications in which the tissue-laceration device is used to lacerate a leaflet of a native or prosthetic valve, the cutting element-housing leg is positioned distally to the leaflet such that a distal base of the cutting element-housing leg is disposed distal to a distal surface of the leaflet, at a base of the leaflet. The cutting element-housing leg is then moved toward the leaflet proximally to move the leaflet proximally toward a first one of the two or more radially-expandable stabilizing legs and in order to trap the first leaflet between the cutting element-housing leg and the first one of the two or more radially-expandable stabilizing legs.

[0013] There is therefore provided, in accordance with some applications of the invention, tissuelaceration device, including: an elongate shaft having a distal end; a tissue-stabilizing tool including:

[0014] (a) a proximal tubular portion, and

[0015] (b) two or more radially-expandable stabilizing legs extending from the proximal tubular portion and configured to expand radially away from a central longitudinal axis of the tissue-laceration device, the tissue-stabilizing tool shaped so as to define a lumen for longitudinal movement of the elongate shaft along the central longitudinal axis of the tissue-laceration device and with respect to the tissue-stabilizing tool; a cutting element-housing leg coupled to the elongate shaft and movable toward and away from each one of the two or more radially-expandable stabilizing legs in order to trap tissue between the cutting element-housing leg and each one of the two or more radially-expandable stabilizing legs; a retractable cutting element disposed within the cutting element-housing leg and movable with respect to the cutting element-housing leg; and one or more adjusting bars coupled between the elongate shaft and the cutting element-housing leg, the adjusting bar facilitating movement of the cutting element-housing leg toward and away from the two or more radially-expandable stabilizing legs and toward and away from the elongate shaft.

[0016] In an application, the cutting element includes a blade.

[0017] In an application, the apparatus further includes a steerable tube, and the elongate shaft and the tissue-stabilizing tool are axially advanceable within the steerable tube.

[0018] In an application, the cutting element is configured to be exposed from within the cutting element-housing leg once the tissue has been trapped between the cutting element-housing leg and each one of the two or more radially-expandable stabilizing legs.

[0019] In an application, the cutting element is configured to be exposed from within the cutting element-housing leg prior to the tissue has been trapped between the cutting element-housing leg and each one of the two or more radially-expandable stabilizing legs, and the cutting element is brought in contact with the tissue by movement of the cutting element-housing leg toward the radially- expandable stabilizing leg.

[0020] In an application: the cutting element-housing leg is shaped so as to define a slit for movement of the cutting element along the slit, the cutting element-housing leg is deliverable to a first leaflet of a native valve (1) such that a distal base of the cutting element-housing leg is disposed distal to a distal surface of the leaflet at a base of the leaflet, and (2) the cutting element is disposed at a distal portion of the slit, the cutting element-housing leg is subsequently movable proximally to bring the first leaflet toward a first one of the two or more radially-expandable stabilizing legs, and the cutting element is movable proximally, axially along the slit in order to lacerate the leaflet.

[0021] In an application, a distal end of a first one of the two or more radially-expandable stabilizing legs is configured to be disposed against a proximal surface of the leaflet at the base of the leaflet while the distal base of the cutting element-housing leg is disposed against the distal surface of the leaflet at the base of the leaflet.

[0022] In an application, the cutting element is movable while the cutting element-housing leg remains stationary.

[0023] In an application: the cutting element-housing leg is shaped so as to define a slit for movement of the cutting element along the slit, the cutting element-housing leg is deliverable to a first leaflet of a prosthetic valve (1) such that a distal base of the cutting element-housing leg is disposed distal to a distal surface of the leaflet at a base of the leaflet, and (2) the cutting element is disposed at a distal portion of the slit, the cutting element-housing leg is subsequently movable proximally to bring the first leaflet toward a first one of the two or more radially-expandable stabilizing legs, and the cutting element is movable proximally, axially along the slit in order to lacerate the leaflet.

[0024] In an application, a distal end of a first one of the two or more radially-expandable stabilizing legs is configured to be disposed against a proximal surface of the leaflet at the base of the leaflet while the distal base of the cutting element-housing leg is disposed against the distal surface of the leaflet at the base of the leaflet.

[0025] In an application, the cutting element-housing leg is revolvable around the central longitudinal axis of the tissue-laceration device such that the cutting element-housing leg is positionable opposite each one of the two or more radially-expandable stabilizing legs.

[0026] In an application, the cutting element-housing leg includes a tubular element that surrounds the elongate shaft, the tubular element is longitudinally slidable with respect to the elongate shaft and revolvable around the central longitudinal axis. In an application, the two or more radially-expandable stabilizing legs include three radially- expandable stabilizing legs, and the cutting element-housing leg is revolvable in 30 - 120 degree increments so as to align the cutting element-housing leg with each of the three radially-expandable stabilizing legs.

[0027] In an application: the tubular element of the cutting element-housing leg is shaped so as to define a lateral protrusion, and the proximal tubular portion of the tissue-stabilizing tool is shaped so as to define two or more lateral grooves for receiving the lateral protrusion, and positioning of the protrusion within each one of the two or more lateral grooves enables alignment between the cutting element-housing leg and each one of the two or more radially- expandable stabilizing legs.

[0028] In an application, the apparatus further includes a cutting element-housing leg movement tube which facilitates axial movement of the tubular element of the cutting element-housing leg and revolving of the tubular element of the cutting element-housing leg such that (1) distal axial movement of the movement tube distally moves the protrusion out of a first one of the lateral grooves; (2) revolving of the movement tube revolves the cutting element-housing leg; and (3) proximal axial movement of the movement tube proximally moves the protrusion within a second one of the lateral grooves.

[0029] In an application, the cutting element-housing leg movement tube has a lumen for passage therethrough of the elongate shaft.

[0030] In an application, the cutting element-housing leg movement tube is welded to the tubular element of the cutting element-housing leg.

[0031] In an application, the apparatus further includes a steerable tube, and the cutting elementhousing leg movement tube is axially advanceable within the steerable tube.

[0032] There is additionally provided, in accordance with some applications of the invention, a tissuelaceration device, including: an elongate shaft having a distal end; a tissue-stabilizing tool including:

[0033] (a) a proximal tubular portion, and (b) two or more radially-expandable stabilizing legs extending from the proximal tubular portion and configured to expand radially away from a central longitudinal axis of the tissue-laceration device, the tissue-stabilizing tool shaped so as to define a lumen for longitudinal movement of the elongate shaft along the central longitudinal axis of the tissue-laceration device and with respect to the tissue-stabilizing tool; a cutting element-housing leg coupled to the elongate shaft and movable toward and away from each one of the two or more radially-expandable stabilizing legs in order to trap tissue between the cutting element-housing leg and each one of the two or more radially-expandable stabilizing legs, cutting element-housing leg being revolvable around the central longitudinal axis of the tissuelaceration device such that the cutting element-housing leg is positionable opposite each one of the two or more radially-expandable stabilizing legs; and a retractable cutting element disposed within the cutting element-housing leg and movable with respect to the cutting element-housing leg.

[0034] In accordance with some applications of the invention, the apparatus further includes a steerable tube, and the elongate shaft and the tissue-stabilizing tool are axially advanceable within the steerable tube.

[0035] In an application, the cutting element is configured to be exposed from within the cutting element-housing leg once the tissue has been trapped between the cutting element-housing leg and each one of the two or more radially-expandable stabilizing legs.

[0036] In an application, the cutting element is configured to be exposed from within the cutting element-housing leg prior to the tissue has been trapped between the cutting element-housing leg and each one of the two or more radially-expandable stabilizing legs, and the cutting element is brought in contact with the tissue by movement of the cutting element-housing leg toward the radially- expandable stabilizing leg.

[0037] In an application: the cutting element-housing leg is shaped so as to define a slit for movement of the cutting element along the slit, the cutting element-housing leg is deliverable to a first leaflet of a native valve (1) such that a distal base of the cutting element-housing leg is disposed distal to a distal surface of the leaflet at a base of the leaflet, and (2) the cutting element is disposed at a distal portion of the slit, the cutting element-housing leg is subsequently movable proximally to bring the first leaflet toward a first one of the two or more radially-expandable stabilizing legs, and the cutting element is movable proximally, axially along the slit in order to lacerate the leaflet.

[0038] In an application, a distal end of a first one of the two or more radially-expandable stabilizing legs is configured to be disposed against a proximal surface of the leaflet at the base of the leaflet while the distal base of the cutting element-housing leg is disposed against the distal surface of the leaflet at the base of the leaflet.

[0039] In an application, the cutting element is movable while the cutting element-housing leg remains stationary.

[0040] In an application: the cutting element-housing leg is shaped so as to define a slit for movement of the cutting element along the slit, the cutting element-housing leg is deliverable to a first leaflet of a prosthetic valve (1) such that a distal base of the cutting element-housing leg is disposed distal to a distal surface of the leaflet at a base of the leaflet, and (2) the cutting element is disposed at a distal portion of the slit, the cutting element-housing leg is subsequently movable proximally to bring the first leaflet toward a first one of the two or more radially-expandable stabilizing legs, and the cutting element is movable proximally, axially along the slit in order to lacerate the leaflet.

[0041] In an application, a distal end of a first one of the two or more radially-expandable stabilizing legs is configured to be disposed against a proximal surface of the leaflet at the base of the leaflet while the distal base of the cutting element-housing leg is disposed against the distal surface of the leaflet at the base of the leaflet.

[0042] In an application, the cutting element is movable while the cutting element-housing leg remains stationary.

[0043] There is further provided, in accordance with some applications of the invention, a method for lacerating leaflet tissue, the method including: advancing an elongate shaft having a distal end between leaflets of a native heart valve; positioning a tissue-stabilizing tool proximally of the leaflets, the tissue-stabilizing tool including:

[0044] (a) a proximal tubular portion, and (b) two or more radially-expandable stabilizing legs extending from the proximal tubular portion and configured to expand radially away from a central longitudinal axis of the tissue-laceration device, the tissue-stabilizing tool shaped so as to define a lumen for longitudinal movement of the elongate shaft along the central longitudinal axis of the tissue-laceration device and with respect to the tissue-stabilizing tool; positioning distally of the leaflets a cutting element-housing leg coupled to the elongate shaft such that a distal base of the cutting element-housing leg is disposed distal to a distal surface of a first one of the leaflets at a base of the leaflet; moving the cutting element-housing leg toward the first leaflet proximally to move the first leaflet proximally toward a first one of the two or more radially-expandable stabilizing legs and in order to trap the first leaflet between the cutting element-housing leg and the first one of the two or more radially-expandable stabilizing legs; and subsequently, moving a retractable cutting element with respect to the cutting element-housing leg in order to lacerate the first leaflet.

[0045] In an application, positioning tissue-stabilizing tool proximally of the leaflets includes positioning a distal end each one of the two or more radially-expandable stabilizing legs against a proximal surface of the leaflet at the base of the leaflet.

[0046] In an application, advancing the elongate shaft includes advancing the elongate shaft through a steerable tube, and the method further includes steering the steerable tube.

[0047] In an application, the method further includes exposing the cutting element from within the cutting element-housing leg subsequently to the trapping of the first leaflet between the cutting element-housing leg and the first one of the two or more radially-expandable stabilizing legs.

[0048] In an application, the method further includes exposing the cutting element from within the cutting element-housing leg prior to the trapping of the first leaflet between the cutting elementhousing leg and the first one of the two or more radially-expandable stabilizing legs.

[0049] In an application, the method further includes exposing the cutting element from within a slit defined by the cutting element-housing leg.

[0050] In an application, during the positioning of the cutting element-housing leg, the cutting element is disposed at a distal portion of the slit, and moving the cutting element with respect to the cutting element-housing leg includes moving the cutting element proximally within the slit. In an application, the method further includes revolving the cutting element-housing leg around the central longitudinal axis of the tissue-laceration device such that the cutting elementhousing leg is positionable opposite each one of the two or more radially-expandable stabilizing legs.

[0051] In an application, the method further includes: revolving the cutting element-housing leg such that the distal base of the cutting elementhousing leg is disposed distal to a distal surface of a second one of the leaflets at a base of the second leaflet; moving the cutting element-housing leg toward the second leaflet proximally to move the first leaflet proximally toward a second one of the two or more radially-expandable stabilizing legs and in order to trap the second leaflet between the cutting element-housing leg and the second one of the two or more radially-expandable stabilizing legs; and subsequently, moving the cutting element with respect to the cutting element-housing leg in order to lacerate the second leaflet.

[0052] In an application, the cutting element-housing leg includes a tubular element that surrounds the elongate shaft, and the method further includes longitudinally sliding the tubular element with respect to the elongate shaft and revolving the tubular element around the central longitudinal axis.

[0053] In an application, the two or more radially-expandable stabilizing legs include three radially- expandable stabilizing legs, and revolving the cutting element-housing leg includes revolving the cutting element-housing leg in 30 - 120 degree increments so as to align the cutting element-housing leg with each of the three radially-expandable stabilizing legs.

[0054] In an application: the tubular element of the cutting element-housing leg is shaped so as to define a lateral protrusion, and the proximal tubular portion of the tissue-stabilizing tool is shaped so as to define two or more lateral grooves for receiving the lateral protrusion, and the method further includes aligning the cutting element-housing leg and each one of the two or more radially-expandable stabilizing legs by positioning the protrusion within each one of the two or more lateral grooves.

[0055] In an application, the method further includes a cutting element-housing leg movement tube, and the method further includes facilitating axial movement of the tubular element of the cutting element-housing leg and revolving of the tubular element of the cutting element-housing leg by the cutting element-housing leg movement tube by: (1) distally axially moving the movement tube, distally moving the protrusion out of a first one of the lateral grooves; (2) revolving the movement tube and by revolving the movement tube, revolving the cutting element-housing leg; and (3) proximally axially moving the movement tube, proximally moving the protrusion within a second one of the lateral grooves.

[0056] In an application, the cutting element-housing leg movement tube has a lumen, and the method further includes passing the elongate shaft through the cutting element-housing leg movement tube.

[0057] In an application, the cutting element-housing leg movement tube is welded to the tubular element of the cutting element-housing leg.

[0058] In an application, the method further includes axially advancing the cutting element-housing leg movement within the steerable tube.

[0059] There is yet further provided, in accordance with some applications of the invention a method for lacerating leaflet tissue, the method including: advancing an elongate shaft having a distal end between leaflets of a prosthetic heart valve; positioning a tissue-stabilizing tool proximally of the leaflets, the tissue-stabilizing tool including:

[0060] (a) a proximal tubular portion, and

[0061] (b) two or more radially-expandable stabilizing legs extending from the proximal tubular portion and configured to expand radially away from a central longitudinal axis of the tissue-laceration device, the tissue-stabilizing tool shaped so as to define a lumen for longitudinal movement of the elongate shaft along the central longitudinal axis of the tissue-laceration device and with respect to the tissue-stabilizing tool; positioning distally of the leaflets a cutting element-housing leg coupled to the elongate shaft such that a distal base of the cutting element-housing leg is disposed distal to a distal surface of a first one of the leaflets at a base of the leaflet; moving the cutting element-housing leg toward the first leaflet proximally to move the first leaflet proximally toward a first one of the two or more radially-expandable stabilizing legs and in order to trap the first leaflet between the cutting element-housing leg and the first one of the two or more radially-expandable stabilizing legs; and subsequently, moving a retractable cutting element with respect to the cutting element-housing leg in order to lacerate the first leaflet. There is also provided, in accordance with some applications of the invention, a method for lacerating tissue, the method including: advancing an elongate shaft having a distal end in a vicinity of a tissue to be lacerated; positioning a tissue-stabilizing tool proximally of the tissue, the tissue-stabilizing tool including:

[0062] (a) a proximal tubular portion, and

[0063] (b) two or more radially-expandable stabilizing legs extending from the proximal tubular portion and configured to expand radially away from a central longitudinal axis of the tissue-laceration device, the tissue-stabilizing tool shaped so as to define a lumen for longitudinal movement of the elongate shaft along the central longitudinal axis of the tissue-laceration device and with respect to the tissue-stabilizing tool; positioning distally of a first portion of the tissue a cutting element-housing leg coupled to the elongate shaft such that a distal base of the cutting element-housing leg is disposed distal to a distal surface of the first portion of the tissue; moving the cutting element-housing leg toward the first portion of the tissue proximally to move the first portion of the tissue proximally toward a first one of the two or more radially- expandable stabilizing legs and in order to trap the first portion of the tissue between the cutting element-housing leg and the first one of the two or more radially-expandable stabilizing legs; and subsequently, moving a retractable cutting element with respect to the cutting element-housing leg in order to lacerate the first portion of the tissue.

[0064] In an application, positioning tissue-stabilizing tool proximally of the first portion of the tissue includes positioning a distal end each one of the two or more radially-expandable stabilizing legs against a proximal surface of the first portion of the tissue.

[0065] In an application, advancing the elongate shaft includes advancing the elongate shaft through a steerable tube, and the method further includes steering the steerable tube.

[0066] In an application, the method further includes exposing the cutting element from within the cutting element-housing leg subsequently to the trapping of the first portion of the tissue between the cutting element-housing leg and the first one of the two or more radially-expandable stabilizing legs. In an application, the method further includes exposing the cutting element from within the cutting element-housing leg prior to the trapping of the first portion of the tissue between the cutting element-housing leg and the first one of the two or more radially-expandable stabilizing legs.

[0067] In an application, the method further includes exposing the cutting element from within a slit defined by the cutting element-housing leg.

[0068] In an application, during the positioning of the cutting element-housing leg, the cutting element is disposed at a distal portion of the slit, and moving the cutting element with respect to the cutting element-housing leg includes moving the cutting element proximally within the slit.

[0069] In an application, the method further includes revolving the cutting element-housing leg around the central longitudinal axis of the tissue-laceration device such that the cutting elementhousing leg is positionable opposite each one of the two or more radially-expandable stabilizing legs.

[0070] In an application, the method further includes: revolving the cutting element-housing leg such that the distal base of the cutting elementhousing leg is disposed distal to a distal surface of a second portion of the tissue; moving the cutting element-housing leg toward the second leaflet proximally to move the second portion of the tissue proximally toward a second one of the two or more radially-expandable stabilizing legs and in order to trap the second portion of the tissue between the cutting elementhousing leg and the second one of the two or more radially-expandable stabilizing legs; and subsequently, moving the cutting element with respect to the cutting element-housing leg in order to lacerate the second portion of the tissue.

[0071] In an application, the cutting element-housing leg includes a tubular element that surrounds the elongate shaft, and the method further includes longitudinally sliding the tubular element with respect to the elongate shaft and revolving the tubular element around the central longitudinal axis.

[0072] In an application, the two or more radially-expandable stabilizing legs include three radially- expandable stabilizing legs, and revolving the cutting element-housing leg includes revolving the cutting element-housing leg in 30 - 120 degree increments so as to align the cutting element-housing leg with each of the three radially-expandable stabilizing legs.

[0073] In an application: the tubular element of the cutting element-housing leg is shaped so as to define a lateral protrusion, and the proximal tubular portion of the tissue-stabilizing tool is shaped so as to define two or more lateral grooves for receiving the lateral protrusion, and the method further includes aligning the cutting element-housing leg and each one of the two or more radially-expandable stabilizing legs by positioning the protrusion within each one of the two or more lateral grooves.

[0074] In an application, the method further includes a cutting element-housing leg movement tube, and the method further includes facilitating axial movement of the tubular element of the cutting element-housing leg and revolving of the tubular element of the cutting element-housing leg by the cutting element-housing leg movement tube by: (1) distally axially moving the movement tube, distally moving the protrusion out of a first one of the lateral grooves; (2) revolving the movement tube and by revolving the movement tube, revolving the cutting element-housing leg; and (3) proximally axially moving the movement tube, proximally moving the protrusion within a second one of the lateral grooves.

[0075] In an application, the cutting element-housing leg movement tube has a lumen, and the method further includes passing the elongate shaft through the cutting element-housing leg movement tube.

[0076] In an application, the cutting element-housing leg movement tube is welded to the tubular element of the cutting element-housing leg.

[0077] In an application, the method further includes axially advancing the cutting element-housing leg movement within the steerable tube.

[0078] There is therefore provided, in accordance with an Inventive Concept 1 of the present invention, a method for lacerating leaflet tissue, the method comprising: advancing an elongate shaft having a distal end between leaflets of a native heart valve; positioning a tissue-stabilizing tool proximally of the leaflets, the tissue-stabilizing tool comprising:

[0079] (a) a proximal tubular portion, and

[0080] (b) two or more radially-expandable stabilizing legs extending from the proximal tubular portion and configured to expand radially away from a central longitudinal axis of the tissue-laceration device, the tissue-stabilizing tool shaped so as to define a lumen for longitudinal movement of the elongate shaft along the central longitudinal axis of the tissue-laceration device and with respect to the tissue-stabilizing tool; positioning distally of the leaflets a cutting element-housing leg coupled to the elongate shaft such that a distal base of the cutting element-housing leg is disposed distal to a distal surface of a first one of the leaflets at a base of the leaflet; moving the cutting element-housing leg toward the first leaflet proximally to move the first leaflet proximally toward a first one of the two or more radially-expandable stabilizing legs and in order to trap the first leaflet between the cutting element-housing leg and the first one of the two or more radially-expandable stabilizing legs; and subsequently, moving a retractable cutting element with respect to the cutting element-housing leg in order to lacerate the first leaflet.

[0081] Inventive Concept 2. The method according to Inventive Concept 1, wherein positioning tissuestabilizing tool proximally of the leaflets comprises positioning a distal end each one of the two or more radially-expandable stabilizing legs against a proximal surface of the leaflet at the base of the leaflet.

[0082] Inventive Concept 3. The method according to Inventive Concept 1, wherein advancing the elongate shaft comprises advancing the elongate shaft through a steerable tube, and wherein the method further comprises steering the steerable tube.

[0083] Inventive Concept 4. The method according to Inventive Concept 1, further comprising exposing the cutting element from within the cutting element-housing leg subsequently to the trapping of the first leaflet between the cutting element-housing leg and the first one of the two or more radially- expandable stabilizing legs.

[0084] Inventive Concept 5. The method according to Inventive Concept 1, further comprising exposing the cutting element from within the cutting element-housing leg prior to the trapping of the first leaflet between the cutting element-housing leg and the first one of the two or more radially-expandable stabilizing legs.

[0085] Inventive Concept 6. The method according to any one of Inventive Concepts 1-5, further comprising exposing the cutting element from within a slit defined by the cutting element-housing leg.

[0086] Inventive Concept 7. The method according to Inventive Concept 6, wherein during the positioning of the cutting element-housing leg, the cutting element is disposed at a distal portion of the slit, and wherein moving the cutting element with respect to the cutting element-housing leg comprises moving the cutting element proximally within the slit.

[0087] Inventive Concept 8. The method according to any one of Inventive Concepts 1-5, further comprising revolving the cutting element-housing leg around the central longitudinal axis of the tissue-laceration device such that the cutting element-housing leg is positionable opposite each one of the two or more radially-expandable stabilizing legs.

[0088] Inventive Concept 9. The method according to Inventive Concept 8, further comprising: revolving the cutting element-housing leg such that the distal base of the cutting elementhousing leg is disposed distal to a distal surface of a second one of the leaflets at a base of the second leaflet; moving the cutting element-housing leg toward the second leaflet proximally to move the first leaflet proximally toward a second one of the two or more radially-expandable stabilizing legs and in order to trap the second leaflet between the cutting element-housing leg and the second one of the two or more radially-expandable stabilizing legs; and subsequently, moving the cutting element with respect to the cutting element-housing leg in order to lacerate the second leaflet.

[0089] Inventive Concept 10. The method according to Inventive Concept 8, wherein the cutting elementhousing leg comprises a tubular element that surrounds the elongate shaft, and wherein the method further comprises longitudinally sliding the tubular element with respect to the elongate shaft and revolving the tubular element around the central longitudinal axis.

[0090] Inventive Concept 11. The method according to Inventive Concept 10, wherein the two or more radially-expandable stabilizing legs comprise three radially-expandable stabilizing legs, and wherein revolving the cutting element-housing leg comprises revolving the cutting element-housing leg in 30 - 120 degree increments so as to align the cutting element-housing leg with each of the three radially- expandable stabilizing legs.

[0091] Inventive Concept 12. The method according to Inventive Concept 10, wherein: the tubular element of the cutting element-housing leg is shaped so as to define a lateral protrusion, and wherein the proximal tubular portion of the tissue-stabilizing tool is shaped so as to define two or more lateral grooves for receiving the lateral protrusion, and the method further comprises aligning the cutting element-housing leg and each one of the two or more radially-expandable stabilizing legs by positioning the protrusion within each one of the two or more lateral grooves.

[0092] Inventive Concept 13. The method according to Inventive Concept 12, further comprising a cutting element-housing leg movement tube, and wherein the method further comprises facilitating axial movement of the tubular element of the cutting element-housing leg and revolving of the tubular element of the cutting element-housing leg by the cutting element-housing leg movement tube by: (1) distally axially moving the movement tube, distally moving the protrusion out of a first one of the lateral grooves; (2) revolving the movement tube and by revolving the movement tube, revolving the cutting element-housing leg; and (3) proximally axially moving the movement tube, proximally moving the protrusion within a second one of the lateral grooves.

[0093] Inventive Concept 14. The method according to Inventive Concept 13, wherein the cutting elementhousing leg movement tube has a lumen, and wherein the method further comprises passing the elongate shaft through the cutting element-housing leg movement tube.

[0094] Inventive Concept 15. The method according to Inventive Concept 13, wherein the cutting elementhousing leg movement tube is welded to the tubular element of the cutting element-housing leg.

[0095] Inventive Concept 16. The method according to Inventive Concept 13, further comprising a steerable tube, and wherein the method further comprises axially advancing the cutting element-housing leg movement within the steerable tube.

[0096] There is further provided, in accordance with an Inventive Concept 17 of the present invention, method for lacerating leaflet tissue, the method comprising: advancing an elongate shaft having a distal end between leaflets of a prosthetic heart valve; positioning a tissue-stabilizing tool proximally of the leaflets, the tissue-stabilizing tool comprising:

[0097] (a) a proximal tubular portion, and

[0098] (b) two or more radially-expandable stabilizing legs extending from the proximal tubular portion and configured to expand radially away from a central longitudinal axis of the tissue-laceration device, the tissue-stabilizing tool shaped so as to define a lumen for longitudinal movement of the elongate shaft along the central longitudinal axis of the tissue-laceration device and with respect to the tissue-stabilizing tool; positioning distally of the leaflets a cutting element-housing leg coupled to the elongate shaft such that a distal base of the cutting element-housing leg is disposed distal to a distal surface of a first one of the leaflets at a base of the leaflet; moving the cutting element-housing leg toward the first leaflet proximally to move the first leaflet proximally toward a first one of the two or more radially-expandable stabilizing legs and in order to trap the first leaflet between the cutting element-housing leg and the first one of the two or more radially-expandable stabilizing legs; and subsequently, moving a retractable cutting element with respect to the cutting element-housing leg in order to lacerate the first leaflet.

[0099] Inventive Concept 18. The method according to Inventive Concept 17, wherein positioning tissuestabilizing tool proximally of the leaflets comprises positioning a distal end each one of the two or more radially-expandable stabilizing legs against a proximal surface of the leaflet at the base of the leaflet.

[0100] Inventive Concept 19. The method according to Inventive Concept 17, wherein advancing the elongate shaft comprises advancing the elongate shaft through a steerable tube, and wherein the method further comprises steering the steerable tube.

[0101] Inventive Concept 20. The method according to Inventive Concept 17, further comprising exposing the cutting element from within the cutting element-housing leg subsequently to the trapping of the first leaflet between the cutting element-housing leg and the first one of the two or more radially- expandable stabilizing legs.

[0102] Inventive Concept 21. The method according to Inventive Concept 17, further comprising exposing the cutting element from within the cutting element-housing leg prior to the trapping of the first leaflet between the cutting element-housing leg and the first one of the two or more radially-expandable stabilizing legs.

[0103] Inventive Concept 22. The method according to any one of Inventive Concepts 17-21, further comprising exposing the cutting element from within a slit defined by the cutting element-housing leg.

[0104] Inventive Concept 23. The method according to Inventive Concept 22, wherein during the positioning of the cutting element-housing leg, the cutting element is disposed at a distal portion of the slit, and wherein moving the cutting element with respect to the cutting element-housing leg comprises moving the cutting element proximally within the slit. Inventive Concept 24. The method according to any one of Inventive Concepts 17-21, further comprising revolving the cutting element-housing leg around the central longitudinal axis of the tissue-laceration device such that the cutting element-housing leg is positionable opposite each one of the two or more radially-expandable stabilizing legs.

[0105] Inventive Concept 25. The method according to Inventive Concept 24, further comprising: revolving the cutting element-housing leg such that the distal base of the cutting elementhousing leg is disposed distal to a distal surface of a second one of the leaflets at a base of the second leaflet; moving the cutting element-housing leg toward the second leaflet proximally to move the first leaflet proximally toward a second one of the two or more radially-expandable stabilizing legs and in order to trap the second leaflet between the cutting element-housing leg and the second one of the two or more radially-expandable stabilizing legs; and subsequently, moving the cutting element with respect to the cutting element-housing leg in order to lacerate the second leaflet.

[0106] Inventive Concept 26. The method according to Inventive Concept 24, wherein the cutting elementhousing leg comprises a tubular element that surrounds the elongate shaft, and wherein the method further comprises longitudinally sliding the tubular element with respect to the elongate shaft and revolving the tubular element around the central longitudinal axis.

[0107] Inventive Concept 27. The method according to Inventive Concept 26, wherein the two or more radially-expandable stabilizing legs comprise three radially-expandable stabilizing legs, and wherein revolving the cutting element-housing leg comprises revolving the cutting element-housing leg in 30 - 120 degree increments so as to align the cutting element-housing leg with each of the three radially- expandable stabilizing legs.

[0108] Inventive Concept 28. The method according to Inventive Concept 26, wherein: the tubular element of the cutting element-housing leg is shaped so as to define a lateral protrusion, and wherein the proximal tubular portion of the tissue-stabilizing tool is shaped so as to define two or more lateral grooves for receiving the lateral protrusion, and the method further comprises aligning the cutting element-housing leg and each one of the two or more radially-expandable stabilizing legs by positioning the protrusion within each one of the two or more lateral grooves. Inventive Concept 29. The method according to Inventive Concept 28, further comprising a cutting element-housing leg movement tube, and wherein the method further comprises facilitating axial movement of the tubular element of the cutting element-housing leg and revolving of the tubular element of the cutting element-housing leg by the cutting element-housing leg movement tube by: (1) distally axially moving the movement tube, distally moving the protrusion out of a first one of the lateral grooves; (2) revolving the movement tube and by revolving the movement tube, revolving the cutting element-housing leg; and (3) proximally axially moving the movement tube, proximally moving the protrusion within a second one of the lateral grooves.

[0109] Inventive Concept 30. The method according to Inventive Concept 29, wherein the cutting elementhousing leg movement tube has a lumen, and wherein the method further comprises passing the elongate shaft through the cutting element-housing leg movement tube.

[0110] Inventive Concept 31. The method according to Inventive Concept 29, wherein the cutting elementhousing leg movement tube is welded to the tubular element of the cutting element-housing leg.

[0111] Inventive Concept 32. The method according to Inventive Concept 29, further comprising a steerable tube, and wherein the method further comprises axially advancing the cutting element-housing leg movement within the steerable tube.

[0112] There is also, in accordance with an Inventive Concept 33 of the present invention, method for lacerating tissue, the method comprising: advancing an elongate shaft having a distal end in a vicinity of a tissue to be lacerated; positioning a tissue-stabilizing tool proximally of the tissue, the tissue-stabilizing tool comprising:

[0113] (a) a proximal tubular portion, and

[0114] (b) two or more radially-expandable stabilizing legs extending from the proximal tubular portion and configured to expand radially away from a central longitudinal axis of the tissue-laceration device, the tissue-stabilizing tool shaped so as to define a lumen for longitudinal movement of the elongate shaft along the central longitudinal axis of the tissue-laceration device and with respect to the tissue-stabilizing tool; positioning distally of a first portion of the tissue a cutting element-housing leg coupled to the elongate shaft such that a distal base of the cutting element-housing leg is disposed distal to a distal surface of the first portion of the tissue; moving the cutting element-housing leg toward the first portion of the tissue proximally to move the first portion of the tissue proximally toward a first one of the two or more radially- expandable stabilizing legs and in order to trap the first portion of the tissue between the cutting element-housing leg and the first one of the two or more radially-expandable stabilizing legs; and subsequently, moving a retractable cutting element with respect to the cutting element-housing leg in order to lacerate the first portion of the tissue.

[0115] Inventive Concept 34. The method according to Inventive Concept 33, wherein positioning tissuestabilizing tool proximally of the first portion of the tissue comprises positioning a distal end each one of the two or more radially-expandable stabilizing legs against a proximal surface of the first portion of the tissue.

[0116] Inventive Concept 35. The method according to Inventive Concept 33, wherein advancing the elongate shaft comprises advancing the elongate shaft through a steerable tube, and wherein the method further comprises steering the steerable tube.

[0117] Inventive Concept 36. The method according to Inventive Concept 33, further comprising exposing the cutting element from within the cutting element-housing leg subsequently to the trapping of the first portion of the tissue between the cutting element-housing leg and the first one of the two or more radially-expandable stabilizing legs.

[0118] Inventive Concept 37. The method according to Inventive Concept 33, further comprising exposing the cutting element from within the cutting element-housing leg prior to the trapping of the first portion of the tissue between the cutting element-housing leg and the first one of the two or more radially-expandable stabilizing legs.

[0119] Inventive Concept 38. The method according to any one of Inventive Concepts 33-37, further comprising exposing the cutting element from within a slit defined by the cutting element-housing leg.

[0120] Inventive Concept 39. The method according to Inventive Concept 38, wherein during the positioning of the cutting element-housing leg, the cutting element is disposed at a distal portion of the slit, and wherein moving the cutting element with respect to the cutting element-housing leg comprises moving the cutting element proximally within the slit.

[0121] Inventive Concept 40. The method according to any one of Inventive Concepts 33-37, further comprising revolving the cutting element-housing leg around the central longitudinal axis of the tissue-laceration device such that the cutting element-housing leg is positionable opposite each one of the two or more radially-expandable stabilizing legs.

[0122] Inventive Concept 41. The method according to Inventive Concept 40, further comprising: revolving the cutting element-housing leg such that the distal base of the cutting elementhousing leg is disposed distal to a distal surface of a second portion of the tissue; moving the cutting element-housing leg toward the second leaflet proximally to move the second portion of the tissue proximally toward a second one of the two or more radially-expandable stabilizing legs and in order to trap the second portion of the tissue between the cutting elementhousing leg and the second one of the two or more radially-expandable stabilizing legs; and subsequently, moving the cutting element with respect to the cutting element-housing leg in order to lacerate the second portion of the tissue.

[0123] Inventive Concept 42. The method according to Inventive Concept 40, wherein the cutting elementhousing leg comprises a tubular element that surrounds the elongate shaft, and wherein the method further comprises longitudinally sliding the tubular element with respect to the elongate shaft and revolving the tubular element around the central longitudinal axis.

[0124] Inventive Concept 43. The method according to Inventive Concept 42, wherein the two or more radially-expandable stabilizing legs comprise three radially-expandable stabilizing legs, and wherein revolving the cutting element-housing leg comprises revolving the cutting element-housing leg in 30 - 120 degree increments so as to align the cutting element-housing leg with each of the three radially- expandable stabilizing legs.

[0125] Inventive Concept 44. The method according to Inventive Concept 42, wherein: the tubular element of the cutting element-housing leg is shaped so as to define a lateral protrusion, and wherein the proximal tubular portion of the tissue-stabilizing tool is shaped so as to define two or more lateral grooves for receiving the lateral protrusion, and the method further comprises aligning the cutting element-housing leg and each one of the two or more radially-expandable stabilizing legs by positioning the protrusion within each one of the two or more lateral grooves.

[0126] Inventive Concept 45. The method according to Inventive Concept 44, further comprising a cutting element-housing leg movement tube, and wherein the method further comprises facilitating axial movement of the tubular element of the cutting element-housing leg and revolving of the tubular element of the cutting element-housing leg by the cutting element-housing leg movement tube by: (1) distally axially moving the movement tube, distally moving the protrusion out of a first one of the lateral grooves; (2) revolving the movement tube and by revolving the movement tube, revolving the cutting element-housing leg; and (3) proximally axially moving the movement tube, proximally moving the protrusion within a second one of the lateral grooves.

[0127] Inventive Concept 46. The method according to Inventive Concept 45, wherein the cutting elementhousing leg movement tube has a lumen, and wherein the method further comprises passing the elongate shaft through the cutting element-housing leg movement tube.

[0128] Inventive Concept 47. The method according to Inventive Concept 45, wherein the cutting elementhousing leg movement tube is welded to the tubular element of the cutting element-housing leg.

[0129] Inventive Concept 48. The method according to Inventive Concept 45, further comprising a steerable tube, and wherein the method further comprises axially advancing the cutting element-housing leg movement within the steerable tube.

[0130] The present invention will be more fully understood from the following detailed description of applications thereof, taken together with the drawings, in which:

[0131] BRIEF DESCRIPTION OF THE DRAWINGS

[0132] Figs. 1A-B are schematic illustrations of a tissue-laceration device in respective assembled and exploded views, in accordance with some applications of the invention;

[0133] Figs. 2A-J are schematic illustrations of the use of the tissue-laceration device of Figs. 1A-B in a native aortic valve, in accordance with some applications of the invention;

[0134] Fig. 3 is a schematic illustration of an alternative use of the tissue-laceration device of Figs. 1A-B in a native aortic valve, in accordance with some applications of the invention;

[0135] Fig. 4 is a schematic illustration of laceration of a leaflet by the tissue-laceration device of Figs. 1A-B, in accordance with some applications of the invention; and

[0136] Fig. 5 is a schematic illustration of an alternative use of the tissue-laceration device of Figs. 1A-B on a prosthetic aortic valve, in accordance with some applications of the invention.

[0137] DETAILED DESCRIPTION OF EMBODIMENTS

[0138] Reference is now made to Figs. 1 A-B, which are schematic illustrations of systems 20 and 120 comprising a tissue-laceration device 22 in respective assembled and exploded views, in accordance with some applications of the invention. Tissue-laceration device 22 comprises a tissue-stabilizing tool 30 and a cutting element-housing leg 40 which comes in contact with tissue to be lacerated or cut by device 22. Typically, tissue-laceration device 22 is configured to lacerate or cut leaflet tissue of a native valve or of a prosthetic valve. Tissue-laceration device 22 is percutaneously deliverable to a native heart valve or to a prosthetic heart valve in a compressed state in which tissue-stabilizing tool 30 is in a compressed state, and is then expandable at the native valve or at the prosthetic heart valve in order to grasp native leaflets of the native valve or prosthetic leaflets of the prosthetic valve. Tissue-laceration device 22 is typically designated for use at a native or prosthetic aortic valve of a patient. It is to be noted that the scope of the present invention includes use of tissue-laceration device 22 at other native cardiac valves or other prosthetic valves implanted at the native valve of the patient, e.g., a pulmonary valve, a mitral valve, or a tricuspid valve. Additionally, it is to be noted that tissuelaceration device 22 described herein may be used to lacerate any cardiac or vascular tissue within the body of the patient. Further additionally, it is to be noted that tissue-laceration device 22 described herein may be used to lacerate any suitable tissue within the body of the patient. It is to be further noted that tissue-laceration device 22 described herein may be used in a stand-alone procedure for lacerating tissue, i.e., without performing a subsequent procedure such as implanting a prosthetic valve, for example. That is, tissue-laceration device 22 may be used in the heart to alleviate any blood flow obstruction, e.g., by lacerating tissue blocking the left ventricular outflow tract.

[0139] Throughout this application, including the specification and the claims, unless stated otherwise, "proximal" and "distal," are defined with respect to a central longitudinal axis axl of device 22, and with respect to the entry point through which device 22 is passed within the body of the patient. For example, “proximal” indicates a position closer to the entry point, and “distal” indicates a position further away from the entry point.

[0140] Tissue-laceration device 22 comprises an elongate shaft 24 having a distal end 26. Tissuestabilizing tool 30 is shaped so as to define a lumen for longitudinal movement of elongate shaft 24 along central longitudinal axis axl of tissue-laceration device 22 and with respect to tissue-stabilizing tool 30. Tissue-stabilizing tool 30 comprises a proximal tubular portion 34, and two or more (e.g., three, as shown) radially-expandable stabilizing legs 32, (e.g., legs 32a, 32b and 32c, as shown) extending distally from proximal tubular portion 34. Legs 32 are compressed during delivery of tissue-stabilizing tool 30 to the tissue site and are configured to expand radially away from central longitudinal axis axl of tissue-laceration device 22 once exposed from within an external steerable tube 80. As is described hereinbelow, tissue-stabilizing tool 30 is shaped so as to define a plurality of slits 33 at the proximal base of each leg 32 at the junction between leg 32 and proximal tubular portion 34. Slits 33 increase the lateral and radial flexibility of each leg 32. During manufacture of device 22, slits 33 are formed by a laser cut in order to increase flexibility and strength to legs 32.

[0141] It is to be noted that legs 32 comprise a metal, e.g., nitinol. The metal forming legs 32 may be of any stiffness. For some applications, legs 32 comprise a material that is a non-metal, e.g., foam, plastic or silicone. For some applications, legs 32 comprise a metal as a base, that is covered by a secondary material comprising a non-metal.

[0142] Each leg 32 is shaped so as to define a longitudinal cutting element-guiding groove 38. For some applications, groove 38 runs through leg 32 such that groove 38 extends from an inner surface to an outer surface of each leg 32 along the length of groove 38. For applications in which groove 38 extends to an outer surface of leg 32, a protective covering covers the outer surface of groove 38 such that tissue surrounding the outer surface of leg 32 is protected during movement of a cutting element 51. For some applications, groove 38 is shaped as an indentation and does not extend to the outer surface of leg 32 such that tissue surrounding the outer surface of leg 32 is protected during movement of cutting element 51.

[0143] Cutting element-housing leg 40 is shaped to as to define an elongate leg portion 47 that defines a slit 44 for advancement of a retractable cutting element 51 therethrough. For some applications, cutting element comprises a blade, e.g., microtome, razor, or scalpel. For some applications of the present invention, cutting element 51 can be a mechanical, a blade, laser, optical fiber, serrated knife, radiofrequency tools, or any other suitable cutting element, or any combination thereof.

[0144] For applications in which cutting element 51 comprises a blade, the blade has a length of 1.5 - 5 mm, e.g., 3 mm.

[0145] It is to be noted that elongate leg portion 47 comprises a metal, e.g., nitinol. The metal forming elongate leg portion 47 may be of any stiffness. For some applications, elongate leg portion 47 comprises a material that is a non-metal, e.g., foam, plastic or silicone. For some applications, elongate leg portion 47 comprises a metal as a base, that is covered by a secondary material comprising a non-metal.

[0146] Elongate leg portion 47 is coupled to first and second plates 46 which each define a cutting element-housing slit 48 each having two portions. A first diagonal portion 50 of slit 48 which houses cutting element 51 in its retracted state, and second longitudinal portion 52 of slit 48 which facilitates longitudinal movement of cutting element 51 during laceration of tissue. Typically, cutting element 51 moves while cutting element-housing leg 40 and tissue-stabilizing tool 30 remain stationary. That means that during laceration of tissue by cutting element 51, only cutting element 51 moves (e.g., by movement of a cutting element-movement element (not shown) coupled to cutting element 51) while the rest of tissue-laceration device 22 does not move. In other words, a distal portion of tissuelaceration device 22 does not change its relative position with respect to the tissue being lacerated.

[0147] Typically, longitudinal portion 52 of slit 48 has a length of 15 - 25 mm, e.g., 20 mm. That is, the travel range of cutting element 51 is 15 - 25 mm, e.g., 20 mm.

[0148] Cutting element-housing leg 40 is revolvable around central longitudinal axis axl of tissuelaceration device 22 such that cutting element-housing leg 40 is positionable opposite each one of radially-expandable stabilizing legs 32. Cutting element-housing leg 40 comprises a tubular element 42 at a proximal end of elongate leg portion 47. Tubular element 42 surrounds elongate shaft 24. Tubular element 42 is longitudinally slidable with respect to elongate shaft 24 and revolvable around central longitudinal axis axl. Cutting element-housing leg 40 is shaped so as to define a plurality of slits 45 at the proximal base of elongate leg portion 47 at the junction between leg portion 47 and tubular element 42. Slits 45 increase the lateral and radial flexibility of elongate leg portion 47. During manufacture of device 22, slits 45 are formed by a laser cut in order to increase flexibility and strength to elongate leg portion 47.

[0149] As is described hereinbelow, tubular element 42 is shaped so as to define a lateral protrusion 43, and proximal tubular portion 34 of tissue-stabilizing tool 30 is shaped so as to define two or more (e.g., three, as shown) lateral grooves 36 for receiving lateral protrusion 43 in order to rotationally lock cutting element-housing leg 40 with respect each leg 32 of tissue-stabilizing tool 30. As is described hereinbelow, since device 22 comprises three legs 32, cutting element-housing leg 40 is configured to rotate in between 30- and 120-degree increments, e.g., 120 degrees as shown, in order to align elongate leg portion 47 of the cutting element-housing leg 40 with each of the three radially- expandable stabilizing legs 32. Positioning of protrusion 43 within each one of lateral grooves 36 enables alignment between elongate leg portion 47 of cutting element-housing leg 40 and each radially-expandable stabilizing leg 32.

[0150] Cutting element-housing leg 40 may stop at various positions during the revolving of cutting element-housing leg 40. That is, leg 40 may stop at 3 - 9 positions, e.g., 6 positions or 3 positions, as shown. Device 22 comprises a cutting element-housing leg movement tube 70 which facilitates axial movement of tubular element 42 of cutting element-housing leg 40 and revolving of tubular element 42 of cutting element-housing leg 40 such that (1) distal axial movement of movement tube 70 distally moves protrusion 43 out of a first one of lateral grooves 36; (2) revolving of movement tube 70 revolves cutting element-housing leg 40; and (3) proximal axial movement of movement tube 70 proximally moves protrusion 43 within a second one of lateral grooves 36. Typically, but not necessarily, cutting element-housing leg movement tube 70 is fixedly coupled to, e.g., by welding, tubular element 42 of cutting element-housing leg 40.

[0151] Cutting element-housing leg movement tube 70 has a lumen for passage therethrough of elongate shaft 24. Cutting element-housing leg movement tube 70 is axially advanceable within steerable tube 80.

[0152] One or more adjusting bars 54 are coupled between elongate shaft 24 and cutting elementhousing leg 40. Adjusting bars 54 facilitate movement of cutting element-housing leg 40 toward and away from radially-expandable stabilizing legs 32 and toward and away from elongate shaft 24.

[0153] Elongate shaft 24 and tissue-stabilizing tool 30 are each axially advanceable within a lumen of steerable tube 80. Elongate shaft 24 is fixedly coupled to cutting element-housing leg 40 via a coupling element 58 that surrounds and is fixed to elongate shaft 24. Movement of elongate shaft 24 moves coupling element 58 that, in turn, moves leg portion 47 of cutting element-housing leg 40 radially toward and away from central longitudinal axis axl. Coupling element 58 is shaped so as to define pegs 59 which fit within first coupling holes at a first pivot point 62 at a first end of each adjusting bar 54. Movement of elongate shaft 24, and thereby coupling element 58 moves pegs 59 which apply a force to the coupling holes at pivot point 62 in order to enable adjusting bars 54 to pivot and move radially with respect to elongate shaft 24 and axis axl. Adjusting bars 54 are shaped so as to define second coupling holes at a second pivot point 60 which is at a second end of each adjusting bar 54. A peg 56 passes through the coupling holes of pivot point 60 and through holes of a pivot point of plates 46. The pivot point of plates 46 is typically but not necessarily at a mid-point of each plate 46.

[0154] Distal and proximal movement of elongate shaft 24 moves elongate leg portion 47 of cutting element-housing leg 40 toward and away from each one of radially-expandable stabilizing legs 32 in order to trap tissue between elongate leg portion 47 of cutting element-housing leg 40 and each one of radially-expandable stabilizing legs 32. As will be described hereinbelow, distal movement of elongate shaft 24 applies a pushing force to pegs 59 which then apply a force to the coupling holes at pivot point 62 in order to enable adjusting bars 54 to pivot and move radially away from elongate shaft 24 and axis axl . Movement of adjusting bars 54 radially away from axis axl applies a pushing force to peg 56 at pivot point 60 which pushes plate 46 radially outwardly and thereby moves elongate leg portion 47 of cutting element-housing leg 40 radially away from elongate shaft 24 and axis axl and radially expands elongate leg portion 47. Conversely, proximal movement of elongate shaft 24 applies a pulling force to pegs 59 which then apply a pulling force to the coupling holes at pivot point 62 in order to enable adjusting bars 54 to pivot and move radially toward elongate shaft 24 and axis axl . Movement of adjusting bars 54 radially toward axis axl applies a pulling force to peg 56 at pivot point 60 which pulls plate 46 radially inwardly and thereby moves elongate leg portion 47 of cutting element-housing leg 40 radially toward elongate shaft 24 and axis axl and radially compresses elongate leg portion 47.

[0155] Thus, tissue-laceration device 22 defines a three-bar linkage mechanism 90 which includes (i) elongate shaft 24, (ii) adjusting bars 54, and (iii) elongate leg portion 47 of cutting element-housing leg 40. Three-bar linkage mechanism 90 raises and lowers elongate leg portion 47 of cutting elementhousing leg 40 toward and away from central longitudinal axis axl and proximally toward and distally away from each one of radially-expandable stabilizing legs 32.

[0156] Reference is now made to Figs. 2A-J, which are schematic illustrations of the use of tissuelaceration device 22 for lacerating a native leaflet 102 of a native aortic valve 100, in accordance with some applications of the invention. In Fig. 2A, steerable tube 80 is steered toward native aortic valve 100 and in between the native leaflets in order to deliver the distal portion of tissue-laceration device 22 to the native valve.

[0157] Fig. 2B shows proximal retraction of steerable tube 80 with respect to radially-expandable stabilizing legs 32 in order to expose distal portions of radially-expandable stabilizing legs 32 proximal to the native leaflets 102 of valve 100. Since radially-expandable stabilizing legs 32 are configured to self-expand, legs 32 remain constrained within the lumen of steerable tube 80. Elongate shaft 24 is disposed between the native leaflets 102 of aortic valve 100.

[0158] Further proximal retraction of steerable tube 80, as shown in Fig. 2C, enables radially- expandable stabilizing legs 32 to radially expand automatically. Each leg 32 bends along slits 33 which help to increase flexibility, strength, and range of motion of each leg 32. Fig. 2D shows distal advancement of tissue-laceration device 22 in order to bring the inner surface of each of radially-expandable stabilizing legs 32 in contact with the proximal surface of each leaflet 102. Since system 20 shows device 22 being used at a native aortic valve, the inner surface of each of radially-expandable stabilizing legs 32 is brought in contact with the downstream surface of each leaflet 102. Device 22 is pushed distally such that a base 31 of each leg 32 is brought into contact with a base 104 of each leaflet and leg 32 is disposed against a proximal surface of leaflet 102.

[0159] Additionally, tissue-stabilizing tool 30 functions as a positioning tool which helps position device 22 properly. Each base 31 of legs 32 of tool 30 finds the base of the cusps of the leaflets, (e.g., at the middle of the base of the cusps). Visualization of tissue-stabilizing tool 30 using imaging is then used so as to ensure proper positioning of device 22 with respect to the tissue being lacerated.

[0160] Reference is made to Figs. 2C-D. Collectively, bases 31 of legs 32 define a distal diameter of tissue-stabilizing tool 30. Since legs 32 are self-expandable, the diameter of tissue-stabilizing tool 30 is controlled by relative movement of steerable tube 80 for optimal anatomical fit irrespective of the size of the annulus. Proximal retraction of tube 80 increases the diameter, while distal pushing of tube 80 decreases the diameter. That is, axial movement of tube 80 controls the diameter of tissuestabilizing tool 30 such that tool 30 can adapt itself to an annulus of any size, e.g., in a “one-size-fits- all” approach.

[0161] As shown in Fig. 2D, once radially-expandable stabilizing legs 32 are positioned at the proximal surfaces of leaflets 102, elongate leg portion 47 remains disposed alongside elongate shaft 24 along the central longitudinal axis and in between leaflets 102. Cutting element-housing leg 40 this is deliverable to leaflet 102 (1) such that a distal base 41 of cutting element-housing leg 40 is disposed distal to a distal surface of leaflet 102 and brought into contact with a base of leaflet 102, and (2) cutting element 51 is disposed at a distal portion of slit 48. Leg portion 47 of cutting elementhousing leg 40 is subsequently movable proximally to bring leaflet 102 toward leg 32a.

[0162] Fig. 2E shows distal pushing of elongate shaft 24 in order to move elongate leg portion 47 of cutting element-housing leg 40 toward a first one of radially-expandable stabilizing legs 32a. Distal pushing on shaft 24 moves coupling element 58 which move pegs 59 which apply a force to the coupling holes at pivot point 62 in order to enable adjusting bars 54 to pivot and move radially away from elongate shaft 24 and axis axl . Movement of adjusting bars 54 radially away from axis axl applies a pushing force to peg 56 at pivot point 60 which pushes plate 46 radially outwardly and thereby moves elongate leg portion 47 of cutting element-housing leg 40 radially away from elongate shaft 24 and axis axl and radially expands elongate leg portion 47.

[0163] As shown in Fig. 2E, cutting element 51 is exposed from within first diagonal portion 50 prior to trapping tissue of leaflet 102 between elongate leg portion 47 of cutting element-housing leg 40 and the first one of radially-expandable stabilizing legs 32a. Continued distal pushing of elongate shaft 24 pushes elongate leg portion 47 toward radially-expandable stabilizing leg 32a in order to bring elongate leg portion 47 and cutting element 51 into contact with tissue of leaflet 102. Further continued distal pushing of elongate shaft 24 moves leg portion 47 of cutting element-housing leg 40 further proximally to bring the

[0164] Reference is now made to Fig. 3, which is a schematic illustration of an alternative use of tissue-laceration device 22. As shown in Fig. 3, cutting element 51 is exposed from within first diagonal portion 50 only once tissue of leaflet 102 is trapped between elongate leg portion 47 of cutting element-housing leg 40 and the first one of radially-expandable stabilizing legs 32a.

[0165] Reference is now made to Figs. 2E and 3. As is common in the prior art, a cutting element is typically brought in contact with the leaflet and the cutting element applies pressure to the leaflet. By contrast, in the present invention, leaflet tissue is moved against a stabilizing element radially- expandable leg 32 by leg portion 47 of cutting element-housing leg 40, and trapped between radially- expandable leg 32 and leg portion 47 of cutting element-housing leg 40 in order then apply the cutting force by cutting element 51 to the leaflet tissue once the tissue of leaflet 102 has been trapped between radially-expandable leg 32 and leg portion 47 of cutting element-housing leg 40.

[0166] Reference is again made to Fig. 2F. Tissue of leaflet 102 is trapped between radially- expandable leg 32 and leg portion 47 of cutting element-housing leg 40. Base 31 of leg 32 and a distal base 41 of leg portion 47 of cutting element-housing leg 40 are disposed at base 104 of leaflet 102. Once leaflet 102 is trapped, cutting element 51 is moved proximally along longitudinal portion 52 which facilitates longitudinal movement of cutting element 51 during laceration of tissue. Typically, cutting element 51 moves while cutting element-housing leg 40 and tissue-stabilizing tool 30 remain stationary. That means that during laceration of tissue by cutting element 51, only cutting element 51 moves (e.g., by movement of a cutting element-movement element (not shown) coupled to cutting element 51) while the rest of tissue-laceration device 22 does not move. In other words, a distal portion 21 of tissue-laceration device 22 does not change its relative position with respect to the tissue being lacerated, i.e., in this case leaflet 102. Typically, in the prior art, the entire device is moved in order to facilitate laceration of the tissue. In the present invention, by contrast, only cutting element 51 is moved relative to the remaining portions of device 22 in order to lacerate the tissue of leaflet 102.

[0167] Fig. 2G shows cutting element 51 moving proximally along slit 44 in cutting element-housing leg 40 and along groove 38 of radially-expandable leg 32 in order to lacerate tissue of leaflet 102.

[0168] Once cutting element 51 has lacerated tissue of a first leaflet 102a, cutting element 51 is moved distally such that it is retracted within first diagonal portion 50 of slit 48 which houses cutting element 51 in its retracted state, and leg portion 47 of cutting element-housing leg 40 is returned to alignment with elongate shaft 24, as shown in Fig. 2H. Proximal movement of elongate shaft 24 applies a pulling force to enable adjusting bars 54 to pivot and move radially inwardly toward elongate shaft 24 and axis axl. Movement of adjusting bars 54 radially toward axis axl pulls plate 46 radially inwardly and thereby moves elongate leg portion 47 of cutting element-housing leg 40 radially toward elongate shaft 24 and axis axl and radially compresses elongate leg portion 47.

[0169] Once cutting element-housing leg 40 has been moved radially inwardly, as shown in Fig. 2H, cutting element-housing leg 40 is revolved in order to bring cutting element-housing leg into alignment with a second one of radially-expandable stabilizing legs 32b.

[0170] As shown in Fig. 2H and 2J, cutting element-housing leg movement tube 70 is pushed distally (Step B of Fig. 2J from its proximal position in Step A of Fig. 2J) in order to push tubular element 42 of cutting element-housing leg 40. This disengages protrusion 43 of tubular element 42 from within a first one of lateral grooves 36a of proximal tubular portion 34 of tissue-stabilizing tool 30.

[0171] In Fig. 21, tubular element 42 of cutting element-housing leg 40 is revolved, e.g., by revolving cutting element-housing leg movement tube 70, such that leg portion 47 of cutting element-housing leg 40 is positioned in alignment with a second one of radially-expandable stabilizing legs 32b (Step C of Fig. 2J). Cutting element-housing leg movement tube 70 is then moved proximally (e.g., by pulling on cutting element-housing leg movement tube 70) in order to position protrusion 43 within a second one of lateral grooves 36b of proximal tubular portion 34 of tissue-stabilizing tool 30 (Step D of Fig. 2 J). Positioning protrusion 43 within groove 36 rotationally locks cutting element-housing leg 40 with respect to tissue-stabilizing tool 30.

[0172] Fig. 4 shows laceration of first and second native leaflets 102a and 102b in order to expose coronary arteries 152 and 154, in accordance with some applications of the invention. For some applications, laceration of native leaflets 102a and 102b removes any obstruction of the coronary arteries in cases in which a prosthetic valve is subsequently implanted. It is to be noted that any number of slits may be made in each leaflet.

[0173] Typically, tissue-laceration devices, or other cutting devices known in the art, form an excised gap in the tissue being cut. For example, a section of tissue is removed from the body of the patient following the cutting. This could leave behind a gap in the tissue in any shape, e.g., a triangular slot. Tissue-laceration device 22 described herein is used to form a slit without excising a portion of tissue.

[0174] Following laceration of leaflets 102, leg portion 47 of cutting element- housing leg 40 is brought in alignment with elongate shaft 24 as described hereinabove, and radially-expandable stabilizing legs 32 are radially collapsed, e.g., by distal advancement of steerable tube 80 over legs 32. Tissue-laceration device 22 is then withdrawn from the body of the patient.

[0175] Fig. 5 shows a system 120 for laceration of prosthetic leaflets 202 of a prosthetic valve 200 already implanted at a native aortic valve 100, in accordance with some applications of the invention. For some applications, laceration of prosthetic leaflets 202 removes any obstruction of the coronary arteries in cases in which a second prosthetic valve is subsequently implanted, e.g., in a valve-in-valve procedure. System 120 is similar to system 20 described hereinabove and like reference numeral relate to like parts. That is, device 22 is used for laceration of native leaflets, as described in Figs. 2A-J, 3, and 4, as well as for laceration of prosthetic leaflets, as described in Fig. 5.

[0176] Following laceration of leaflets 202, leg portion 47 of cutting element-housing leg 40 is brought in alignment with elongate shaft 24 as described hereinabove, and radially-expandable stabilizing legs 32 are radially collapsed, e.g., by distal advancement of steerable tube 80 over legs 32. Tissue-laceration device 22 is then withdrawn from the body of the patient.

[0177] Reference is now made to Figs. 1A-5. It is to be noted that although tissue-laceration device 22 described herein are described as being configured for use at a native or prosthetic aortic valve of the patient, the tissue-laceration device may also be configured, mutatis mutandis, to be used at other native or prosthetic cardiac valves of the patient, e.g., the pulmonary valve, the mitral valve and the tricuspid valve. Additionally, it is to be noted that tissue-laceration device 22 described herein may be used to lacerate any cardiac or vascular tissue within the body of the patient. Further additionally, it is to be noted that tissue-laceration device 22 described herein may be used to lacerate any suitable tissue within the body of the patient. It is to be further noted that tissue-laceration device 22 described herein may be used in a stand-alone procedure for lacerating tissue, i.e., without performing a subsequent procedure such as implanting a prosthetic valve, for example. That is, tissue-laceration device 22 may be used in the heart to alleviate any blood flow obstruction, e.g., by lacerating tissue blocking the left ventricular outflow tract.

[0178] It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof that are not in the prior art, which would occur to persons skilled in the art upon reading the foregoing description.

Claims

CLAIMS1. A tissue-laceration device, comprising: an elongate shaft having a distal end; a tissue-stabilizing tool comprising:(a) a proximal tubular portion, and(b) two or more radially-expandable stabilizing legs extending from the proximal tubular portion and configured to expand radially away from a central longitudinal axis of the tissue-laceration device, the tissue-stabilizing tool shaped so as to define a lumen for longitudinal movement of the elongate shaft along the central longitudinal axis of the tissue-laceration device and with respect to the tissue-stabilizing tool; a cutting element-housing leg coupled to the elongate shaft and movable toward and away from each one of the two or more radially-expandable stabilizing legs in order to trap tissue between the cutting element-housing leg and each one of the two or more radially-expandable stabilizing legs; a retractable cutting element disposed within the cutting element-housing leg and movable with respect to the cutting element-housing leg; and one or more adjusting bars coupled between the elongate shaft and the cutting element-housing leg, the adjusting bar facilitating movement of the cutting element-housing leg toward and away from the two or more radially-expandable stabilizing legs and toward and away from the elongate shaft.

2. The tissue-laceration device according to claim 1, wherein the cutting element comprises a blade.

3. The tissue-laceration device according to claim 1, further comprising a steerable tube, and wherein the elongate shaft and the tissue-stabilizing tool are axially advanceable within the steerable tube.

4. The tissue-laceration device according to claim 1, wherein the cutting element is configured to be exposed from within the cutting element-housing leg once the tissue has been trapped between the cutting element-housing leg and each one of the two or more radially-expandable stabilizing legs.

5. The tissue-laceration device according to claim 1, wherein the cutting element is configured to be exposed from within the cutting element-housing leg prior to the tissue has been trapped between the cutting element-housing leg and each one of the two or more radially-expandable stabilizing legs,and wherein the cutting element is brought in contact with the tissue by movement of the cutting element-housing leg toward the radially-expandable stabilizing leg.

6. The tissue-laceration device according to any one of claims 1-5, wherein: the cutting element-housing leg is shaped so as to define a slit for movement of the cutting element along the slit, the cutting element-housing leg is deliverable to a first leaflet of a native valve (1) such that a distal base of the cutting element-housing leg is disposed distal to a distal surface of the leaflet at a base of the leaflet, and (2) the cutting element is disposed at a distal portion of the slit, the cutting element-housing leg is subsequently movable proximally to bring the first leaflet toward a first one of the two or more radially-expandable stabilizing legs, and the cutting element is movable proximally, axially along the slit in order to lacerate the leaflet.

7. The tissue-laceration device according to claim 6, wherein a distal end of a first one of the two or more radially-expandable stabilizing legs is configured to be disposed against a proximal surface of the leaflet at the base of the leaflet while the distal base of the cutting element-housing leg is disposed against the distal surface of the leaflet at the base of the leaflet.

8. The tissue-laceration device according to claim 6, wherein the cutting element is movable while the cutting element-housing leg remains stationary.

9. The tissue-laceration device according to any one of claims 1-5, wherein: the cutting element-housing leg is shaped so as to define a slit for movement of the cutting element along the slit, the cutting element-housing leg is deliverable to a first leaflet of a prosthetic valve (1) such that a distal base of the cutting element-housing leg is disposed distal to a distal surface of the leaflet at a base of the leaflet, and (2) the cutting element is disposed at a distal portion of the slit, the cutting element-housing leg is subsequently movable proximally to bring the first leaflet toward a first one of the two or more radially-expandable stabilizing legs; and the cutting element is movable proximally, axially along the slit in order to lacerate the leaflet.

10. The tissue-laceration device according to claim 9, wherein a distal end of a first one of the two or more radially-expandable stabilizing legs is configured to be disposed against a proximal surface of the leaflet at the base of the leaflet while the distal base of the cutting element-housing leg is disposed against the distal surface of the leaflet at the base of the leaflet.

11. The tissue-laceration device according to claim 9, wherein the cutting element is movable while the cutting element-housing leg remains stationary.

12. The tissue-laceration device according to any one of claims 1-5, wherein the cutting elementhousing leg is revolvable around the central longitudinal axis of the tissue-laceration device such that the cutting element-housing leg is positionable opposite each one of the two or more radially - expandable stabilizing legs.

13. The tissue-laceration device according to claim 12, wherein the cutting element-housing leg comprises a tubular element that surrounds the elongate shaft, the tubular element is longitudinally slidable with respect to the elongate shaft and revolvable around the central longitudinal axis.

14. The tissue-laceration device according to claim 13, wherein the two or more radially - expandable stabilizing legs comprise three radially-expandable stabilizing legs, and wherein the cutting element-housing leg is revolvable in 30 - 120 degree increments so as to align the cutting element-housing leg with each of the three radially-expandable stabilizing legs.

15. The tissue-laceration device according to claim 13, wherein: the tubular element of the cutting element-housing leg is shaped so as to define a lateral protrusion, and wherein the proximal tubular portion of the tissue-stabilizing tool is shaped so as to define two or more lateral grooves for receiving the lateral protrusion, and positioning of the protrusion within each one of the two or more lateral grooves enables alignment between the cutting element-housing leg and each one of the two or more radially- expandable stabilizing legs.

16. The tissue-laceration device according to claim 15, further comprising a cutting elementhousing leg movement tube which facilitates axial movement of the tubular element of the cutting element-housing leg and revolving of the tubular element of the cutting element-housing leg such that (1) distal axial movement of the movement tube distally moves the protrusion out of a first one of the lateral grooves; (2) revolving of the movement tube revolves the cutting element-housing leg; and (3) proximal axial movement of the movement tube proximally moves the protrusion within a second one of the lateral grooves.

17. The tissue-laceration device according to claim 16, wherein the cutting element-housing leg movement tube has a lumen for passage therethrough of the elongate shaft.

18. The tissue-laceration device according to claim 16, wherein the cutting element-housing leg movement tube is welded to the tubular element of the cutting element-housing leg.

19. The tissue- laceration device according to claim 16, further comprising a steerable tube, and wherein the cutting element-housing leg movement tube is axially advanceable within the steerable tube.

20. A tissue-laceration device, comprising: an elongate shaft having a distal end; a tissue-stabilizing tool comprising:(a) a proximal tubular portion, and(b) two or more radially-expandable stabilizing legs extending from the proximal tubular portion and configured to expand radially away from a central longitudinal axis of the tissue-laceration device, the tissue-stabilizing tool shaped so as to define a lumen for longitudinal movement of the elongate shaft along the central longitudinal axis of the tissue-laceration device and with respect to the tissue-stabilizing tool; a cutting element-housing leg coupled to the elongate shaft and movable toward and away from each one of the two or more radially-expandable stabilizing legs in order to trap tissue between the cutting element-housing leg and each one of the two or more radially-expandable stabilizing legs, cutting element-housing leg being revolvable around the central longitudinal axis of the tissuelaceration device such that the cutting element-housing leg is positionable opposite each one of the two or more radially-expandable stabilizing legs; and a retractable cutting element disposed within the cutting element-housing leg and movable with respect to the cutting element-housing leg.

21. The tissue-laceration device according to claim 20, wherein the cutting element comprises a blade.

22. The tissue-laceration device according to any one of claims 20-21, wherein the cutting element-housing leg comprises a tubular element that surrounds the elongate shaft, the tubular element is longitudinally slidable with respect to the elongate shaft and revolvable around the central longitudinal axis.

23. The tissue-laceration device according to claim 22, wherein the two or more radially- expandable stabilizing legs comprise three radially-expandable stabilizing legs, and wherein thecutting element-housing leg is revolvable in 30 - 120 degree increments so as to align the cutting element-housing leg with each of the three radially-expandable stabilizing legs.

24. The tissue-laceration device according to claim 22, wherein: the tubular element of the cutting element-housing leg is shaped so as to define a lateral protrusion, and wherein the proximal tubular portion of the tissue-stabilizing tool is shaped so as to define two or more lateral grooves for receiving the lateral protrusion, and positioning of the protrusion within each one of the two or more lateral grooves enables alignment between the cutting element-housing leg and each one of the two or more radially- expandable stabilizing legs.

25. The tissue-laceration device according to claim 24, further comprising a cutting elementhousing leg movement tube which facilitates axial movement of the tubular element of the cutting element-housing leg and revolving of the tubular element of the cutting element-housing leg such that (1) distal axial movement of the movement tube distally moves the protrusion out of a first one of the lateral grooves; (2) revolving of the movement tube revolves the cutting element-housing leg; and (3) proximal axial movement of the movement tube proximally moves the protrusion within a second one of the lateral grooves.

26. The tissue-laceration device according to claim 25, wherein the cutting element-housing leg movement tube has a lumen for passage therethrough of the elongate shaft.

27. The tissue-laceration device according to claim 25, wherein the cutting element-housing leg movement tube is welded to the tubular element of the cutting element-housing leg.

28. The tissue-laceration device according to claim 25, further comprising a steerable tube, and wherein the cutting element-housing leg movement tube is axially advanceable within the steerable tube.

29. The tissue-laceration device according to any one of claims 20-21, further comprising a steerable tube, and wherein the elongate shaft and the tissue-stabilizing tool are axially advanceable within the steerable tube.

30. The tissue-laceration device according to any one of claims 20-21, wherein the cutting element is configured to be exposed from within the cutting element-housing leg once the tissue has been trapped between the cutting element-housing leg and each one of the two or more radially-expandable stabilizing legs.

31. The tissue-laceration device according to any one of claims 20-21 , wherein the cutting element is configured to be exposed from within the cutting element-housing leg prior to the tissue has been trapped between the cutting element-housing leg and each one of the two or more radially-expandable stabilizing legs, and wherein the cutting element is brought in contact with the tissue by movement of the cutting element-housing leg toward the radially-expandable stabilizing leg.

32. The tissue-laceration device according to any one of claims 20-21, wherein: the cutting element-housing leg is shaped so as to define a slit for movement of the cutting element along the slit, the cutting element-housing leg is deliverable to a first leaflet of a native valve (1) such that a distal base of the cutting element-housing leg is disposed distal to a distal surface of the leaflet at a base of the leaflet, and (2) the cutting element is disposed at a distal portion of the slit, the cutting element-housing leg is subsequently movable proximally to bring the first leaflet toward a first one of the two or more radially-expandable stabilizing legs; and the cutting element is movable proximally, axially along the slit in order to lacerate the leaflet.

33. The tissue-laceration device according to claim 32, wherein a distal end of a first one of the two or more radially-expandable stabilizing legs is configured to be disposed against a proximal surface of the leaflet at the base of the leaflet while the distal base of the cutting element-housing leg is disposed against the distal surface of the leaflet at the base of the leaflet.

34. The tissue-laceration device according to claim 32, wherein the cutting element is movable while the cutting element-housing leg remains stationary.

35. The tissue-laceration device according to any one of claims 20-21, wherein: the cutting element-housing leg is shaped so as to define a slit for movement of the cutting element along the slit, the cutting element-housing leg is deliverable to a first leaflet of a prosthetic valve (1) such that a distal base of the cutting element-housing leg is disposed distal to a distal surface of the leaflet at a base of the leaflet, and (2) the cutting element is disposed at a distal portion of the slit, the cutting element-housing leg is subsequently movable proximally to bring the first leaflet toward a first one of the two or more radially-expandable stabilizing legs; and the cutting element is movable proximally, axially along the slit in order to lacerate the leaflet.

36. The tissue-laceration device according to claim 35, wherein a distal end of a first one of the two or more radially-expandable stabilizing legs is configured to be disposed against a proximalsurface of the leaflet at the base of the leaflet while the distal base of the cutting element-housing leg is disposed against the distal surface of the leaflet at the base of the leaflet.

37. The tissue-laceration device according to claim 35, wherein the cutting element is movable while the cutting element-housing leg remains stationary.

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