Patent Description:
Clot retrieval devices are used in mechanical thrombectomy for endovascular intervention, often in cases where patients are suffering from conditions such as acute ischemic stroke (AIS), myocardial infarction (MI), and pulmonary embolism (PE). Acute obstructions may include clot, misplaced devices, migrated devices, large emboli and the like. Thromboembolism occurs when part or all of a thrombus breaks away from the blood vessel wall. This clot (now called an embolus) is then carried in the direction of blood flow. An ischemic stroke may result if the clot lodges in the cerebral vasculature. A pulmonary embolism may result if the clot originates in the venous system or in the right side of the heart and lodges in a pulmonary artery or branch thereof. Clots may also develop and block vessels locally without being released in the form of an embolus-this mechanism is common in the formation of coronary blockages. There are significant challenges associated with designing clot removal devices that can deliver high levels of performance. First, there are a number of access challenges that make it difficult to deliver devices. In cases where access involves navigating the aortic arch (such as coronary or cerebral blockages) the configuration of the arch in some patients makes it difficult to position a guide catheter. These difficult arch configurations are classified as either type <NUM> or type <NUM> aortic arches with type <NUM> arches presenting the most difficulty.

The tortuousity challenge is even more severe in the arteries approaching the brain. For example it is not unusual at the distal end of the internal carotid artery that the device will have to navigate a vessel segment with a <NUM>° bend, a <NUM>° bend and a <NUM>° bend in quick succession over a few centimeters of vessel. In the case of pulmonary embolisms, access is through the venous system and then through the right atrium and ventricle of the heart. The right ventricular outflow tract and pulmonary arteries are delicate vessels that can easily be damaged by inflexible or high profile devices. For these reasons it is desirable that the clot retrieval device be compatible with as low profile and flexible a guide catheter as possible.

Second, the vasculature in the area in which the clot may be lodged is often fragile and delicate. For example neurovascular vessels are more fragile than similarly sized vessels in other parts of the body and are in a soft tissue bed. Excessive tensile forces applied on these vessels could result in perforations and hemorrhage. Pulmonary vessels are larger than those of the cerebral vasculature, but are also delicate in nature, particularly those more distal vessels.

Third, the clot may comprise any of a range of morphologies and consistencies. Long strands of softer clot material may tend to lodge at bifurcations or trifurcations, resulting in multiple vessels being simultaneously occluded over significant lengths. More mature and organized clot material is likely to be less compressible than softer fresher clot, and under the action of blood pressure it may distend the compliant vessel in which it is lodged. Furthermore the inventors have discovered that the properties of the clot may be significantly changed by the action of the devices interacting with it. In particular, compression of a blood clot causes dehydration of the clot and results in a dramatic increase in both clot stiffness and coefficient of friction.

The challenges described above need to be overcome for any devices to provide a high level of success in removing clot and restoring flow. Existing devices do not adequately address these challenges, particularly those challenges associated with vessel trauma and clot properties.

The disclosure of <CIT> provides a clot removal device for removing clot from a body vessel comprising an expandable structure and an elongate member. <CIT> relates to clot retrieval devices with an outer member with tubular collars and segments attached to these tubular collars.

It is an object of the present design to provide devices to meet the above-stated needs. It is therefore desirable for a clot retrieval device to remove clot from cerebral arteries in patients suffering AIS, from coronary native or graft vessels in patients suffering from MI, and from pulmonary arteries in patients suffering from PE and from other peripheral arterial and venous vessels in which clot is causing an occlusion. The invention relates to a clot retrieval device for retrieving a clot from a blood vessel as defined in independent claim <NUM>. Further embodiments have been specified in the dependent claims.

In some examples, the device includes pinch features along at the site of an occlusion (e.g., in the mid internal carotid artery (ICA)). The device can be configured to reperfuse a vessel and/or remove a clot that has a fibrin core. In some examples, the fibrin core can be in a mid- or distal-position in the clot surrounded by relatively soft thrombus.

In some examples, the device can be configured to remove a clot in the M1 bifurcation.

In some examples, the device can be configured to remove a clot in the M2 bifurcation.

According to the invention, the device includes a caged portion which includes a distal end; a proximal end; an inner cage having a network of inner struts; and an outer cage having a network of outer struts. The inner cage and the outer cage include a delivery configuration within a microcatheter and a deployed configuration distal of the microcatheter operable to retrieve at least a portion of the clot. The device includes a distal pinching portion located proximate the distal end of the caged portion, and a proximal pinching portion located proximate the proximal end of the caged portion, each pinching portion includes at least one pinching cell comprising a collapsed state and an expanded state distal of the microcatheter operable to tweeze at least a portion of the clot. Each pinching cell includes a plurality of strut members configured to actuate and pinch the clot between the plurality of strut members. The plurality of strut members are positioned about a central strut member of the plurality of strut members, each strut member joined at common respective proximal and distal ends.

In some examples, each pinching cell can be operable to tweeze the clot on movement from the collapsed state to a clot pinching state of the expanded state until a portion of the clot can be compressed between the plurality of strut members.

In some examples, each pinching cell can include a ratio of diameters of each pinching cell between the collapsed state and the expanded state can be from approximately <NUM>:<NUM> to <NUM>:<NUM>.

In some examples, each pinching cell can include a radiopaque marker disposed on the plurality of strut members.

In some examples, each pinching cell can include a pinching structure having a plurality of strut members and a central strut member of the plurality of strut members; a first collar having a first collar lumen; and a second collar having a second collar lumen; wherein the plurality of strut members and the central strut member connect the first collar to the second collar.

In some examples, the inner cage can be a plurality of pinching cells operable to tweeze at least a portion of the clot.

In some examples, each cell of the plurality of pinching cells can include a pinching structure having a plurality of strut members and a central strut member of the plurality of strut members; a first collar having a first collar lumen; and a second collar having a second collar lumen; wherein the plurality of strut members and the central strut member connect the first collar to the second collar.

In some examples, the plurality of pinching cells can include at least one radiopaque marker disposed on the pinching structure.

In some examples, each cell of the plurality of pinching cells can include the collapsed state and the expanded state distal of the microcatheter operable to tweeze at least a portion of the clot.

In some examples, the device can include an elongated member can include a distal end connected to a proximal end of the proximal pinching portion, the elongated member operable to move the clot retrieval device in a distal or proximal direction.

In some examples, the network of struts can be connected to the network of inner struts.

In some examples, the pinching portion can include a pinching structure having a plurality of strut members and a central strut member of the plurality of strut members; a first collar having a first collar lumen; and a second collar having a second collar lumen; wherein the plurality of strut members and the central strut member connect the first collar to the second collar.

In some examples, the device includes a proximal pinching portion located proximate the proximal end of the caged portion. The proximal pinching portion can include a proximal end; and an elongated member can include a distal end connected to the proximal end of the pinching portion. The elongated member can be operable to move the clot retrieval device in a distal direction or proximal direction.

In some examples, the pinching portion can include a pinching structure having a plurality of strut members and a central strut member of the plurality of strut members; a first collar having a first collar lumen; and a second collar can include a second collar lumen; wherein the plurality of strut members and the central strut member connect the first collar to the second collar.

Other aspects and features of the present disclosure will become apparent to those of ordinary skill in the art, upon reviewing the following detailed description in conjunction with the accompanying figures.

The above and further aspects of this disclosure are further discussed with the following description of the accompanying drawings, in which like numerals indicate like structural elements and features in various figures. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating principles of the disclosure. The figures depict one or more implementations of the inventive devices, by way of example only, not by way of limitation. It is expected that those of skill in the art can conceive of and combining elements from multiple figures to better suit the needs of the user.

Specific examples of the present disclosure are now described in detail with reference to the Figures, where identical reference numbers indicate elements which are functionally similar or identical. The examples address many of the deficiencies associated with traditional catheters, such as inefficient clot removal and inaccurate deployment of catheters to a target site.

Accessing the various vessels within the vascular, whether they are coronary, pulmonary, or cerebral, involves well-known procedural steps and the use of a number of conventional, commercially-available accessory products. These products, such as angiographic materials and guidewires are widely used in laboratory and medical procedures. When these products are employed in conjunction with the system of this disclosure in the description below, their function and exact constitution are not described in detail.

Although the description of the disclosure is in many cases in the context of treatment of intracranial arteries, the disclosure may also be used in other body passageways as previously described.

Specific embodiments of the present disclosure are now described in detail with reference to the figures, wherein identical reference numbers indicate identical or functionality similar elements. The terms "distal" or "proximal" are used in the following description with respect to a position or direction relative to the treating physician. "Distal" or "distally" are a position distant from or in a direction away from the physician. "Proximal" or "proximally" or "proximate" are a position near or in a direction toward the physician.

Accessing cerebral, coronary and pulmonary vessels involves the use of a number of commercially available products and conventional procedural steps. Access products such as guidewires, guide catheters, angiographic catheters and microcatheters are described elsewhere and are regularly used in catheter lab procedures. It is assumed in the descriptions below that these products and methods are employed in conjunction with the device of this disclosure and do not need to be described in detail.

A common theme across many of the disclosed designs is a multi-layer construction in which the device in certain instances can include an outer cage within which, at times, can include an inner cage, both cages being directly or indirectly connected to an elongate member. Turning to <FIG>, one example device <NUM> according to this invention is illustrated. Device <NUM> can include a caged portion <NUM> having a distal end <NUM> and a proximal end <NUM>. The caged portion <NUM> can include an outer cage <NUM> made of a network of outer struts <NUM>. The caged portion <NUM> can include an inner cage <NUM> made of a network of inner struts <NUM>. Device <NUM> can include a distal pinching portion 116a positioned distal of the caged portion <NUM> and having a distal end 118a and a proximal end 120a. The proximal end 120a of the distal pinching portion 116a can be attached at the distal end <NUM> of the caged portion <NUM>. Device <NUM> can include a proximal pinching portion 116b positioned proximal of the caged portion <NUM> and having a distal end 118b and a proximal end 120b. The distal end 118b of the proximal pinching portion 116b can be attached at the proximal end <NUM> of the caged portion <NUM>. In some examples, the one or more pinching portions 116a, 116b can be pinching cells operable to pinch, grip, or tweeze a clot, as will be discussed in detail in <FIG>. As discussed herein, the term "tweeze" or "tweezing" is intended to refer to the sheathing of the pinching cells that causes respective struts to come together and tweeze or grip at least a portion of clot. In this respect, while the numbers of struts in a respective cell need not be limited, at least two strut surfaces must be included so as to tweeze corresponding clot material.

Device <NUM> can also include an elongated member <NUM> having a distal end <NUM>. The distal end <NUM> of the elongated member <NUM> can be attached to the proximal end 120b of the proximal pinching portion 116b. Additionally or alternatively, the distal end <NUM> of the elongated member <NUM> can be attached to the caged portion <NUM>. Device <NUM> can include a delivery configuration within a lumen of a microcatheter, as discussed in <FIG>, and a deployed configuration distal of the microcatheter, as shown.

The elongated member <NUM> can be a tapered wire shaft, and may be made of stainless steel, MP35N, Nitinol or other material of a suitably high modulus and tensile strength. The caged portion <NUM> and the pinching portions 116a, 116b are desirably made from a material capable of recovering its shape automatically once released from a highly strained delivery configuration. A superelastic material such as Nitinol or an alloy of similar properties is particularly suitable. The material could be in many forms such as wire or strip or sheet or tube. A particularly suitable manufacturing process is to laser cut a Nitinol tube and then heat set and electropolish the resultant structure to create a framework of struts and connecting elements. This framework can be any of huge range of shapes as disclosed herein and may be rendered visible under fluoroscopy through the addition of alloying elements (e.g., Platinum) or through a variety of other coatings or marker bands.

<FIG> depicts a close-up view of an example pinching cell <NUM>. Pinching cells <NUM> can be configured embed and/or engage with and grip the clot to retain it securely for retraction. It is understood that each of the herein described pinching cells can be used interchangeably with clot retrieval devices as needed or required. Pinching cell <NUM> can include a first collar <NUM>, a first lumen <NUM>, a second collar <NUM>, and a second lumen <NUM> between which a pinching structure <NUM> is positioned (e.g., between the first and second collar). The pinching structure <NUM> can include strut members 212a, 212b, and 212c. One or more of strut members 212a, 212b, and 212c can be configured as bowed or otherwise including tensioned flex so as to be capable of embedding in a clot and then being actuated to grip and/or pinch the clot during use. The terms "bowed" is intended to refer to a strut that is generally a shape of an arc, while "tension flex" is intended to refer to a strut that has been placed in tension and plastically deformed into a desired shape. Pinching cell <NUM> can include radiopaque markers <NUM> disposed on the one or more strut members.

In some examples, pinching cell <NUM> can be actuated into the pinched state by being unsheathed from a sheath (e.g., a microcatheter), by being pulled, or actuated by one or more pull members, delivering an electric current to one or more of strut members 212a, 212b, and 212c to cause at least a first portion of the one or more of strut members 212a, 212b, and 212c to change from a collapsed state to pinch state. The pinching cell <NUM> can be configured to embed and grip, pinch, and/or "tweeze" the clot, as shown and described more particularly in <FIG>. One or more of strut members 212a, 212b, and 212c can also have one or more radiopaque bands to indicate to the user when the pinching cell <NUM> is pinched, since the distance between struts is decreased when the pinching cell <NUM> is in a pinched state of the expanded state.

The diameter of pinching cell <NUM> can range between approximately <NUM>-<NUM> millimeters, as need or required. One preferred diameter can be approximately <NUM> millimeters. In some examples, pinching cells <NUM> can be small enough to fit in a <NUM> millimeter (<NUM> inch) or <NUM> millimeter (<NUM> inch) ID microcatheter. The pinching cell <NUM> can be constructed from a superelastic material such as Nitinol or an alloy of similar properties. The material could be in many forms such as wire or strip or sheet or tube. A particularly suitable manufacturing process is to laser cut a Nitinol tube and then heat set and electropolish the resultant structure to create a framework of struts. This framework can be any of huge range of shapes as disclosed herein and may be rendered visible under fluoroscopy through the addition of alloying elements (e.g., Platinum) or through a variety of other coatings or marker bands.

Turning to <FIG>, device <NUM> is shown in a delivery configuration collapsed within the delivery system <NUM>. In particular, device <NUM> is in a delivery configuration within a lumen <NUM> of the microcatheter <NUM>. The microcatheter <NUM> can have a distal end <NUM>. Further, the pinching cells <NUM>, can be in a collapsed state, as discussed in detail in <FIG>.

<FIG> is a flow diagram illustrating an exemplary method of removing a clot from a blood vessel of a patient. The method steps in <FIG> can be implemented by any of the example means described herein or by similar means, as will be appreciated. Referring to method <NUM> as outlined in <FIG>, in step <NUM>, deploying a pinching portion of a clot retrieval device into an expanded state from a collapsed state within a blood vessel and proximate the clot, the clot retrieval device can include a caged portion. The caged portion having a distal end, a delivery configuration within a microcatheter and a deployed configuration distal of the microcatheter operable to retrieve at least a portion of the clot. The pinching portion can be located proximate the distal end of the caged portion, and can include the collapsed state and the expanded state distal of the microcatheter operable to pinch at least a portion of the clot. Additionally or alternatively, step <NUM> can include deploying the caged portion of the clot retrieval device into the deployed configurations from the delivery configuration within the clot such that the caged portion is operable to capture at least a portion of the clot. In step <NUM>, advancing a lumen of the microcatheter over the pinching portion such that the pinching portion at least partially collapses into the lumen of the microcatheter.

In step <NUM>, pinching the pinching portion in contact with the portion of the clot on movement from the collapsed state to a clot pinching state of the expanded state until a portion of the clot is compressed between the pinching portion and the microcatheter. The method can further include determining whether the clot is pinched. Determining that the clot is pinched, the method can include withdrawing the microcatheter, the clot retrieval device, and the clot from the blood vessel while maintaining the clot in the clot pinching state of the pinching portion. Determining that the clot is not pinched, the method can include deploying the caged portion of the clot retrieval device into the deployed configurations from the delivery configuration within the clot such that the caged portion is operable to capture at least a portion of the clot; and retracting the microcatheter, the clot retrieval device, and the clot from the blood vessel while the clot remains entangled is the caged portion. Method <NUM> can end after step <NUM>. In other embodiments, additional steps according to the examples described above can be performed.

<FIG> illustrates an example clot removal device. Device <NUM> can include an inner cage <NUM> of the caged portion <NUM> comprised of one or more pinching cells <NUM>. Cells <NUM> can be sequentially arranged end-to-end along a common axis of shaft <NUM>. Cells <NUM> can be in contact with each other (e.g., distal end of a first cell <NUM> touching a proximal end of a second cell <NUM>, and so forth). In other examples, cells <NUM> can each be separated a predetermined distance and/or positioned in a one-to-one ratio with caged portions of device <NUM>. In some examples, more than one cell <NUM> can be included per caged portion. The inner cage <NUM> can be within an outer cage <NUM>. The proximal end <NUM> of the caged portion <NUM> can be operable to attach to an elongated member <NUM> as discussed in detail above.

<FIG> depicts a close-up view of another example pinching cell 600a with strut members 602a, 604a, and 606a now shown with undulating edges. These undulations can be formed by being heat-set, crimped, or otherwise formed as needed or required. <FIG> depicts a close-up view of another example pinching cell 600b with strut members 602b, 604b, and 606b each including one or more eyelets. <FIG> depicts a close-up view of another example pinching cell 600c with strut members 602c, 604c, and 606c now shown with relatively straight, non-curved strut members. <FIG> depicts a close-up view of another example pinching cell 600d with strut members 602d, 604d, and 606d each including one or more notches or indentation. These notches or indentations can be formed by being heat-set, crimped, or otherwise formed as needed or required.

<FIG> illustrate pinching cell states. An example expanded state of the pinching cell <NUM> is depicted in <FIG>. The pinching structure <NUM> has an expanded diameter D1 which can be realized distal of the distal end <NUM> of the microcatheter <NUM>. An example collapsed state of the pinching cell <NUM> is depicted in <FIG>. The pinching structure <NUM> has a collapsed diameter D2 which can be realized within the lumen <NUM> of the microcatheter <NUM>. An example pinched state of the expanded state of the pinching cell <NUM> is depicted in <FIG>. The pinching structure <NUM> having a diameter less than the expanded diameter D1, but greater than the collapsed diameter D2. A ratio of diameters can be calculated by dividing the expanded diameter D1 by the collapsed diameter D2. Alternatively, a ratio can be computed by dividing the collapsed diameter D1 by the expanded diameter D2.

<FIG> illustrates an example clot removal device. Device <NUM> can include a caged portion <NUM>, an elongated member <NUM> having a distal end <NUM>, wherein the distal end <NUM> of the elongated member <NUM> can connect to a proximal end <NUM> of the caged portion <NUM>. The elongated member <NUM> operable to move at least the caged portion <NUM> in a distal or proximal direction upon moving the elongated member <NUM>, whereby such features of device <NUM> can be understood as including features, features, and designs described in <CIT>; <CIT>; <CIT>; <CIT>; and <CIT>.

The device <NUM> of <FIG> can also include a pinching portion <NUM> located adjacent a distal end <NUM> of the caged portion <NUM>. The pinching portion <NUM>, which can be elongated in certain examples, has a distal end <NUM> and a proximal end <NUM>. The proximal end <NUM> of the elongated pinching portion <NUM> connected to the distal end <NUM> of the caged portion <NUM>. The elongated pinching portion <NUM> can be a network of struts in a tubular shape and operable to grip a clot. Similar to the pinching cell <NUM>, the pinching portion <NUM> can have an expanded state, a collapsed state and a clot pinching state of the expanded state, whereby caged portion <NUM> can include a variety of shapes and designs configured for pinching fibrin rich clots, including those described in <CIT>; <CIT>; <CIT>; <CIT>; and <CIT>.

The disclosure is not limited to the examples described, which can be varied in construction and detail. The terms "distal" and "proximal" are used throughout the preceding description and are meant to refer to a positions and directions relative to a treating physician. As such, "distal" or distally" refer to a position distant to or a direction away from the physician. Similarly, "proximal" or "proximally" refer to a position near to or a direction towards the physician.

In describing examples, terminology is resorted to for the sake of clarity. It is intended that each term contemplates its broadest meaning as understood by those skilled in the art and includes all technical equivalents that operate in a similar manner to accomplish a similar purpose. It is also to be understood that the mention of one or more steps of a method does not preclude the presence of additional method steps or intervening method steps between those steps expressly identified. Steps of a method can be performed in a different order than those described herein. It is to be understood that the mention of one or more components in a device or system does not preclude the presence of additional components or intervening components between those components expressly identified.

As discussed herein, a "patient" or "subject" can be a human or any animal. It should be appreciated that an animal can be a variety of any applicable type, including, but not limited to, mammal, veterinarian animal, livestock animal or pet-type animal, etc. As an example, the animal can be a laboratory animal specifically selected to have certain characteristics similar to a human (e.g., rat, dog, pig, monkey, or the like).

Ranges can be expressed herein as from "about" or "approximately" one particular value and/or to "about" or "approximately" another particular value. When such a range is expressed, other exemplary embodiments include from the one particular value and/or to the other particular value.

By "comprising" or "containing" or "including" or "having" is meant that at least the named compound, element, particle, or method step is present in the composition or article or method, but does not exclude the presence of other compounds, materials, particles, method steps, even if the other such compounds, material, particles, method steps have the same function as what is named.

It must also be noted that, as used in the specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

Claim 1:
A clot retrieval device (<NUM>) for retrieving a clot from a blood vessel, comprising:
a caged portion (<NUM>) comprising:
a distal end (<NUM>);
a proximal end (<NUM>);
an inner cage (<NUM>) comprising a network of inner struts (<NUM>); and
an outer cage (<NUM>) comprising a network of struts (<NUM>),
the inner cage and outer cage comprising a delivery configuration within a microcatheter (<NUM>) and a deployed configuration distal of the microcatheter operable to retrieve at least a portion of the clot; and
a distal pinching portion (116a) located proximate the distal end of the caged portion, and
a proximal pinching portion (116b) located proximate the proximal end of the caged portion,
each pinching portion comprising at least one pinching cell (<NUM>) comprising a collapsed state and an expanded state distal of the microcatheter operable to tweeze at least a portion of the clot, wherein each pinching cell further comprises:
a plurality of at least three strut members (212a, 212b, 212c) configured to actuate and pinch the clot from the blood vessel between the plurality of strut members, wherein the plurality of strut members are positioned about a central strut member of the plurality of strut members, each strut member joined at common respective proximal and distal ends only.