Mechanical Thrombectomy Device for Occlusion Capture and Removal

Abstract

A nested mechanical thrombectomy assembly deliverable as a single assembled unit including an outermost mechanical thrombectomy device and at least one inner mechanical thrombectomy device, wherein each mechanical thrombectomy device is operable from a radially compressed state to a radially expanded state. In the radially compressed state, at least one inner mechanical thrombectomy device is disposed within an inner channel of the outermost mechanical thrombectomy device. Each of the outermost mechanical thrombectomy device and the at least one inner mechanical thrombectomy device is operable / deployable independently of each other.

Description

Technical Field

[0001] The present invention relates to a mechanical thrombectomy device used for intravascular thrombectomy treatment to capture and remove occlusions. Specifically, the present invention is directed to a nested mechanical thrombectomy assembly that is deliverable as a single assembled unit and includes two or more mechanical thrombectomy devices that are operable independently of each other for intravascular treatment of occlusions (s). Further, the present invention also relates to a mechanical thrombectomy device, the distal section of which branches into a plurality of secondary self-expanding cage structures to capture tandem vascular occlusions in respective branched blood vessels at a bifurcation site (e.g., a branch). The present invention also includes mechanical thrombectomy devices that are divisible, separable, or splittable.

Background Art

[0002] Arteries or blood vessels in the brain can become blocked, potentially causing acute ischemic stroke (AIS). Endovascular treatment procedures or therapies include mechanical thrombectomy devices that are navigated through the vasculature to capture and retrieve the target occlusion. The occlusion can be identified in various areas of the brain's vasculature. For example, the occlusion can typically be in the aorta of the brain's anatomical structure, which is a blood vessel with a smaller diameter than the main arteries of the brain (e.g., the Internal Carotid Artery (ICA), the ICA terminus (T-lesion, T-occlusion), the Middle Cerebral Artery (MCA), the M1 MCA vertebral artery, or the basilar artery), or in the blood vessels distal downstream thereof (hereinafter, "distal vessels"). These distal vessels are often occluded due to distal embolization resulting from unintended fragments and / or deviation from the retrieval device during the manipulation of the original / primary occlusion that is more proximal to them. To achieve the greatest benefit, it is desirable to capture and retrieve such distal occlusions to achieve recanalization of these distal vessels, but current techniques are insufficient and have several drawbacks and health risks. When treating occlusions in distal vessels, there are additional challenges. One aspect is that distal vessels are often very tortuous and require longer devices to access, which increases the difficulty of navigating and tracking catheters to these positions as the catheter often loses pushability. Additionally, the tissue surrounding these vessels is delicate / fragile, and the brain structure undergoes significant movement that is possible during retrieval. Occlusions in these distal vessels are typically treated using conventional mechanical thrombectomy devices (e.g., conventional stent retrievers). When using conventional mechanical thrombectomy devices (e.g., conventional stent retrievers) in the treatment of emboli located in distal vessels, there is a substantial risk of vessel injury, rupture or perforation, vasospasm, and even hemorrhage. Summary of the Invention Problems to be Solved by the Invention

[0003] It is desirable to develop an improved mechanical thrombectomy device that reduces these risks and thereby improves the overall outcome of capturing and completely removing all occlusions, including those located in distal vessels. Further, it is desirable to develop an improved mechanical thrombectomy device that provides a longer working length than conventional devices suitable for reaching and capturing occlusions located in distal vessels. It is further desirable to develop an improved mechanical thrombectomy device having an enhanced grip on the captured occlusion that minimizes unwanted release that can occur during retrieval through tortuous paths of the distal vessels while reducing the frictional forces imparted to the fragile vessel wall, thereby minimizing the risk of complications due to bleeding.

Means for Solving the Problems

[0004] One aspect of the present invention is directed to a nested mechanical thrombectomy assembly that reduces these risks and thereby improves the overall outcome of capturing and removing one or more occlusions, including those located in distal vessels.

[0005] Another aspect of the present invention relates to a nested mechanical thrombectomy assembly that includes an outermost mechanical thrombectomy device and at least one inner mechanical thrombectomy device. The at least one inner mechanical thrombectomy device has a smaller distal section suitable for retrieving occlusions located in smaller distal vessels while minimizing the frictional forces imparted to the fragile vessel wall, thereby minimizing the risk of complications due to bleeding. Further, the reduced outer diameter / profile of the actuated inner mechanical thrombectomy device forms a more secure grip on the captured distal embolus, thereby reducing the risk of unwanted release while navigating the tortuous path of the distal vessel during retrieval of the captured blood clot.

[0006] Yet another aspect of the present invention relates to a nested mechanical thrombectomy assembly with a maximized axial / longitudinal working length.

[0007] Yet another aspect of the present invention is directed to a nested mechanical thrombectomy device having a larger outer diameter / outer profile mechanical thrombectomy device and at least one smaller outer diameter / outer profile mechanical thrombectomy device, each being operable independently of the other.

[0008] Yet another aspect of the present invention relates to a nested mechanical thrombectomy assembly including two self-expanding cage structures (e.g., stent retrievers) deliverable and retrievable as a single assembled unit to a target site within a blood vessel via a single microcatheter.

[0009] In yet another aspect of the present invention, a nested mechanical thrombectomy assembly is provided for optimizing the complete or total removal of a blood clot (including potential debris) in a single pass.

[0010] Another aspect of the present invention relates to a nested mechanical thrombectomy assembly comprising a single assembled unit of two or more mechanical thrombectomy devices including an outermost mechanical thrombectomy device and at least one inner mechanical thrombectomy device. All mechanical thrombectomy devices can be actuated / deployed independently of each other (i.e., during treatment of an occlusion, all mechanical thrombectomy devices are actuated / deployed independently of each other but in a complete actuation / deployment). Alternatively, less than all mechanical thrombectomy devices can be actuated / deployed independently of each other (i.e., a partial actuation / deployment where one or more mechanical thrombectomy devices are never actuated / deployed during treatment of an occlusion). For example, only the outermost mechanical thrombectomy device, or only the inner mechanical thrombectomy device, but not both, can be actuated / deployed during treatment.

[0011] In one aspect, yet another aspect of the present invention is directed to a nested mechanical thrombectomy assembly that can be delivered as a single assembled unit. The nested mechanical thrombectomy assembly includes an outermost mechanical thrombectomy device that is operable to move from a radially compressed state to a radially expanded state. The outermost mechanical thrombectomy device forms an axially extending inner channel. Additionally, the nested mechanical thrombectomy device further includes a proximal shaft having a lumen that extends axially therethrough. The distal end of the proximal shaft is connected to the proximal end of the outermost mechanical thrombectomy device such that the inner channel communicates with the lumen of the proximal shaft. Further, the nested mechanical thrombectomy device includes at least one inner mechanical thrombectomy device that is operable to move from a radially compressed state to a radially expanded state. In the radially compressed state, the at least one inner mechanical thrombectomy device is disposed within the inner channel of the outermost mechanical thrombectomy device. The nested mechanical thrombectomy device also includes a wire that extends through the lumen of the proximal shaft and is connected to the proximal end of the at least one inner mechanical thrombectomy device. Each of the outermost mechanical thrombectomy device and the at least one inner mechanical thrombectomy device is operable independently of one another.

[0012] Yet another aspect of the present invention relates to a mechanical thrombectomy device that includes a proximal section and a distal section, wherein the proximal section is a single primary self-expanding cage structure, and the distal section is a plurality of secondary self-expanding cage structures that are connected to each other and releasably fixable together in direct physical contact only at the interface with the single primary self-expanding cage structure. Each of the single primary self-expanding cage structure and the plurality of secondary self-expanding cage structures is operable to move from a radially compressed state to a radially expanded state.

[0013] Another aspect of the present invention is directed to a branched microcatheter including a proximal section having a single tubular structure that is integral with, or fixed to, a branched distal section having a plurality of distinct branched tubular structures. The single tubular structure of the proximal section and each of the plurality of distinct branched tubular structures of the branched distal section have associated lumens that are in fluid communication with each other at an interface between the proximal section and the branched distal section.

[0014] Yet another aspect of the present invention relates to a method for using a nested mechanical thrombectomy assembly, the nested mechanical thrombectomy assembly including an outermost mechanical thrombectomy device operable from a radially compressed state to a radially expanded state, the outermost mechanical thrombectomy device forming an axially extending inner channel. The nested mechanical thrombectomy assembly further includes a proximal shaft having a lumen extending axially therethrough. The proximal shaft is connected to the proximal end of the outermost mechanical thrombectomy device such that the inner channel communicates with the lumen of the proximal shaft. Further, the nested mechanical thrombectomy assembly also includes at least one inner mechanical thrombectomy device operable from a radially compressed state to a radially expanded state, the at least one inner mechanical thrombectomy device being disposed within the inner channel of the outermost mechanical thrombectomy device. In addition, the nested mechanical thrombectomy assembly also includes a wire disposed within the lumen of the proximal shaft and connected to the proximal end of the at least one inner mechanical thrombectomy device. Each of the outermost mechanical thrombectomy device and the at least one inner mechanical thrombectomy device is operable independently of each other. The method for using the nested mechanical thrombectomy assembly includes navigating a guide wire through a blood vessel to a target site. Next, a single microcatheter is tracked over the guide wire. Thereafter, the guide wire is withdrawn proximally from the single microcatheter. The nested mechanical thrombectomy assembly is advanced through the single microcatheter while each of the single outermost mechanical thrombectomy device and the at least one inner mechanical thrombectomy device is in a radially compressed state. At least one occlusive mass is captured in the nested mechanical thrombectomy assembly by (i) operating the single outermost mechanical thrombectomy device and / or (ii) operating the at least one inner mechanical thrombectomy device independently. Simultaneously, the single microcatheter and the nested mechanical thrombectomy assembly are withdrawn from the blood vessel together with at least one occlusive mass captured therein.

[0015] In yet another aspect, the present invention relates to a method for capturing a blood clot within a blood vessel. A guide wire is navigated through the blood vessel to a bifurcation site where a single blood vessel branches into a plurality of branch vessels. Next, a single microcatheter is tracked on the guide wire to the bifurcation site, the single microcatheter comprising a proximal section having a single lumen and a bifurcated distal section of a plurality of branch lumens, and while tracking on the guide wire, the plurality of separate branch lumens of the bifurcated distal section of the single microcatheter are releasably fixed together. The guide wire is withdrawn proximally from the single microcatheter. Thereafter, the plurality of branch lumens of the bifurcated distal section of the single microcatheter are It is liberated and can be separated. At the same time, the separated multiple branch lumens of the branched distal section of a single microcatheter are advanced distally into their respective branch blood vessels at the branch site. Next, a mechanical thrombectomy device including a proximal section and a distal section is advanced through the single microcatheter to a position proximal to the branched distal section, the proximal section being a single primary self-expanding cage structure, and the distal section being a plurality of secondary self-expanding cage structures connected to each other only at the interface with the primary self-expanding cage structure, and the plurality of secondary self-expanding cage structures being releasably fixable together in direct physical contact axially while advancing through the single microcatheter to the branched distal section. The plurality of secondary self-expanding cage structures of the mechanical thrombectomy device are liberated and separable while being positioned proximal to the branched distal section within the single microcatheter. The separated plurality of secondary self-expanding cage structures of the mechanical thrombectomy device are advanced distally into each of the separated multiple branch lumens of the branched distal section of the single microcatheter positioned in their respective multiple branch blood vessels at the branch site. Next, the separate plurality of secondary self-expanding cage structures exposed from each of the separate multiple branch lumens of the branched distal section of the single microcatheter are actuated, and in the actuated separate plurality of secondary self-expanding cage structures, at least one occlusive substance disposed in the branch blood vessels at the branch site is traversed and captured in series. Next, the plurality of secondary self-expanding cage structures are retracted into the branch lumen of the single microcatheter together with at least one occlusive substance captured therein. At the same time, the branched microcatheter and the mechanical thrombectomy device, together with the occlusive substance captured therein, are then withdrawn proximally.

[0016] Another aspect of the present invention is directed to a method for capturing blood clots in a blood vessel by navigating a guide wire through a blood vessel to a bifurcation site where a single blood vessel branches into a plurality of branched blood vessels, and then tracking a single microcatheter along the guide wire to the bifurcation site. In the proximal direction, the guide wire is withdrawn from the single microcatheter. A mechanical thrombectomy device including a proximal section and a distal section is advanced through the single microcatheter. The proximal section is a single primary self-expanding cage structure, and the distal section is a plurality of secondary self-expanding cage structures that are connected to each other only at the interface with the primary self-expanding cage structure, and the plurality of secondary self-expanding cage structures can be releasably fixed together in direct physical contact while advancing through the single microcatheter. Next, the plurality of secondary self-expanding cage structures can be released and separated. Next, the separate plurality of secondary self-expanding cage structures are advanced distally into each of the plurality of branched blood vessels at the bifurcation site that traverses at least one occlusion therein. The single primary self-expanding cage structure and the separate plurality of secondary self-expanding cage structures exposed from the single microcatheter are actuated to capture at least one occlusion therein in series. The single primary self-expanding cage structure and the plurality of secondary self-expanding cage structures are withdrawn into the single microcatheter together with at least one occlusion captured therein. Simultaneously or successively one after another, the single microcatheter and the mechanical thrombectomy device are withdrawn in the proximal direction together with at least one occlusion captured therein.

Brief Description of the Drawings

[0017] The above and other features of the present invention will become more readily apparent from the following detailed description of the invention and the drawings that illustrate the invention, and like reference numerals refer to like elements throughout the several views.

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[0018] In the description, the terms "distal" or "proximal" are used in the following description with respect to the position or direction relative to the treating physician or medical interventionalist. "Distal" or "distally" is a position that is far from or in a direction away from the physician or interventionalist. "Proximal" or "proximally" or "proximate" is a position that is close to or in a direction toward the physician or medical interventionalist. The terms "occlusion", "blood clot", "obstruction", or "embolus" are used interchangeably.

[0019] The advantages of the nested mechanical thrombectomy assembly of the present invention can be described herein with respect to the capture and retrieval of distal occlusions (i.e., occlusions (if any) located distally downstream of the aorta), but nevertheless, it is suitable for occlusions in other locations. Various configurations or designs for the capture and retrieval of occlusions are presented.

[0020] In a first exemplary configuration, the nested mechanical thrombectomy assembly of the present invention may comprise two or more mechanical thrombectomy devices that are operable independently of one another. As a single assembled unit, the nested mechanical thrombectomy assembly is deliverable via a single microcatheter (having a non-branching cylindrical tube configuration) for the capture and retrieval of one or more vascular occlusions. Generally, the nested mechanical thrombectomy assembly includes a single primary mechanical thrombectomy device, and one or more secondary mechanical thrombectomy devices are disposed or nested within the inner axial / longitudinal channel of the single primary mechanical thrombectomy device, and each mechanical thrombectomy device is operable independently of one another. When all mechanical thrombectomy devices are in a non-operating / undeployed state, the single primary thrombectomy device is disposed (nested) radially outward with respect to one or more secondary mechanical thrombectomy devices within the inner axial / longitudinal channel of the single primary mechanical thrombectomy device. Based on their arrangement relative to one another while in the non-operating / undeployed state, the single primary mechanical thrombectomy device is hereinafter referred to as the "outermost mechanical thrombectomy device", while one or more secondary mechanical thrombectomy devices may be hereinafter referred to as one or more "inner mechanical thrombectomy devices". Alternative terms may be used to distinguish mechanical thrombectomy devices such as a single "larger mechanical thrombectomy device" having a larger outer diameter / outer profile compared to one or more "smaller mechanical thrombectomy devices" each having a smaller outer diameter / outer profile when each is in an operating / deployed state. Once actuated / deployed, further alternative terms may be used to distinguish the mechanical thrombectomy devices from one another. Specifically, when all mechanical thrombectomy devices are actuated / deployed within a blood vessel, each of one or more distal thrombectomy devices extends further distally with respect to a single proximal mechanical thrombectomy device, so that a single "proximal mechanical thrombectomy device" and one or more "distal thrombectomy devices" may be used.Any of these terms or alternative terms may be used to distinguish an independently operable mechanical thrombectomy device comprising a nested mechanical thrombectomy assembly according to the present invention.

[0021] The exemplary nested mechanical thrombectomy assembly depicted in FIGS. 1A - 1C includes a single outermost mechanical thrombectomy device 105 having an inner mechanical thrombectomy device 110 nested or assembled therein, with each mechanical thrombectomy device 105, 110 being operable independently of the other. The descriptive terms "outermost" and "inner" refer to the radial arrangement of the independently operable mechanical thrombectomy devices that are "nested" together in a compressed, non - operative state. That is, the term "outermost" refers to the radial placement of the mechanical thrombectomy device 105 (i.e., no other mechanical thrombectomy device is disposed radially outward of the outermost mechanical thrombectomy device 105). The single outermost mechanical thrombectomy device 105 has a proximal end 102, an opposite distal end 103, and an axial / longitudinal channel 120 defined therethrough.

[0022] In the exemplary configurations of FIGS. 1A - 1C, the outermost mechanical thrombectomy device 105 has an articulated segmented design that includes three scaffold sections 125a, 125b, 125c (i.e., cells) arranged in series axially / longitudinally in sequence. The first scaffold section 125a is connected at its proximal end to a proximal shaft 130 (e.g., a tube) having an axially / longitudinally defined lumen 135 therethrough. The self - expanding cage structures of each of the scaffold sections 125a, 125b, 125c are formed by one or more struts that are attached to each other via connection points that form a central body 123 that forms an inner axially / longitudinally channel 120 therein. The present invention is not limited to a particular design of the self - expanding cage structure that functions as the outermost mechanical thrombectomy device 105. The drawings depict the self - expanding cage structure of the outermost mechanical thrombectomy device 105 as including a plurality of articulated segmented scaffold sections connected in series axially / longitudinally in sequence, but alternatively, a single - section self - expanding cage structure may be used. When the self - expanding cage structure of the outermost mechanical thrombectomy device is configured as a plurality of articulated segmented scaffold sections, the number of scaffold sections, as well as the number, arrangement, and connection points associated therewith of the struts for each scaffold section, may be modified as desired.

[0023] Inserted or disposed within the inner axial / longitudinal channel 120 of the single outermost mechanical thrombectomy device 105 is the inner mechanical thrombectomy device 110, and each mechanical thrombectomy device 105, 110 is operable independently of the other. The outer diameter / outer profile of the inner mechanical thrombectomy device 110 is radially compressed (i.e., non-operative / undeployed state) when nested, assembled, or coated within the inner axial or longitudinal channel 120 of the single outermost mechanical thrombectomy device 105. The single outermost mechanical thrombectomy device 105 is actuated or deployed (i.e., transitions from a radially compressed non-operative / undeployed state to a radially self-expanding operative or deployed state) by being exposed (i.e., pulled proximally or withdrawn) from the microcatheter 745. Independently thereof, actuation or deployment of the inner mechanical thrombectomy device 110 (i.e., transition from a radially compressed non-operative / undeployed state to a radially expanded operative or deployed state) is achieved when exposed from the outermost mechanical thrombectomy device 105. For example, by pushing the inner mechanical thrombectomy device 110 out from the distal end or tip of the outermost mechanical thrombectomy device 105, the outermost mechanical thrombectomy device remains stationary at a predetermined position within the device.

[0024] In the exemplary configuration of FIG. 1A, the nested mechanical thrombectomy assembly includes two mechanical thrombectomy devices 105, 110 that are concentrically arranged with one inside the other. Specifically, a single inner mechanical thrombectomy device 110 is concentrically arranged within the inner axial / longitudinal channel 120 of a single outermost mechanical thrombectomy device 105. FIG. 8A is a radial cross-sectional view along line VIII(A)-VIII(A) through the nested mechanical thrombectomy assembly of FIG. 1A. As previously mentioned, the present invention contemplates that two or more independently operable inner mechanical thrombectomy devices can be nested within the inner axial / longitudinal channel of the outermost mechanical thrombectomy device. In such a design, within the inner axial / longitudinal channel of the outermost mechanical thrombectomy device, the plurality of inner mechanical thrombectomy devices can be (i) concentrically arranged (e.g., a second inner mechanical thrombectomy device 110b is disposed within the axial / longitudinal passage of a first inner mechanical thrombectomy device 110a) (FIG. 8B), or (ii) arranged parallel to each other in the axial / longitudinal direction (e.g., the first and second inner mechanical thrombectomy devices 110a, 110b are arranged parallel to each other in the axial / longitudinal direction), and both are accommodated within the inner axial / longitudinal channel 120 of a single outermost mechanical thrombectomy device 105 (FIG. 8C).

[0025] To prevent premature or unintentional actuation (i.e., movement in the distal direction) of the inner mechanical thrombectomy device 110 relative to the outermost mechanical thrombectomy device 105, a mechanical structure such as a mechanical restraint device may optionally be used. Any type of mechanical restraint device that allows movement of the inner mechanical thrombectomy device in the distal direction relative to the outer mechanical thrombectomy device may be used only when a deliberately applied force sufficient to overcome the force applied by the mechanical restraint device is received. The mechanical restraint device 975 is depicted in FIG. 9A as a fixed ring that physically crimps around the proximal shaft 130 of the nested mechanical thrombectomy assembly by applying a radially inward force to the proximal shaft 130 that clamps the wire 140 disposed therein. When the nested mechanical thrombectomy assembly is delivered to the target site through the microcatheter as a single assembled unit, the fixed ring 975 prevents unintentional actuation / deployment of the inner mechanical thrombectomy device 110. Actuation or deployment of the inner mechanical thrombectomy device 110 requires the deliberate application of a distal force on the wire 140 sufficient to overcome (i.e., exceed) the restraining force applied by the fixed ring 975.

[0026] The mechanical restraint device 975 of FIG. 9A is disposed proximal to the assembled mechanical thrombectomy devices 105, 110. Alternatively, the mechanical restraint device can be disposed between the inner mechanical thrombectomy device 110 and the outermost inner thrombectomy device 105. For example, in FIG. 9B, the mechanical restraint device is clamped around the inner mechanical thrombectomy device 110 that is radially compressed while in the undeployed / non-operating state within the inner axial / longitudinal channel 120, and is an auxiliary wire 975' that is connected, fixed, or attached to the outermost mechanical thrombectomy device 105. The application of a predetermined distal force on the wire 140 advances the inner mechanical thrombectomy device 110, but the outermost mechanical thrombectomy device 105 remains in place, breaking, snapping, or cutting the auxiliary wire 975' that inhibits the movement of the inner mechanical thrombectomy device 110 relative to the outermost mechanical thrombectomy device 105. When no longer fixed together (i.e., released), the continued application of a distal force on the wire 140 exposes the inner mechanical thrombectomy device 110 from the outermost mechanical thrombectomy device 105 and activates the inner mechanical thrombectomy device.

[0027] Note that the use of the mechanical restraint device is optional and can be completely eliminated, whereby it should be noted that the inner mechanical thrombectomy device 110 is always axially / longitudinally freely movable relative to the outermost mechanical thrombectomy device 105 when within the microcatheter. In such an example where the mechanical restraint device is eliminated, the inner mechanical thrombectomy device 110 is operable by the operator applying a distal force (e.g., pushing) on the wire 140 fixed to its proximal end.

[0028] Figures 1A - 1C depict the sequential stages or steps that occur in the use of the nested mechanical thrombectomy assembly, and all mechanical thrombectomy devices (e.g., the single outermost and innermost mechanical thrombectomy devices 105, 110) are operated independently of one another (hereinafter referred to as the "complete deployment or full activation" of the nested mechanical thrombectomy device). Specifically, the activation of the single outermost mechanical thrombectomy device 105 occurs first, followed by the subsequent activation of one or more inner mechanical thrombectomy devices (s) 110. Using the nested mechanical thrombectomy assembly of the present invention in this manner serves multiple functional purposes. The initial activation of the outermost mechanical thrombectomy device 105 can function as an anchor within the blood vessel during the subsequent activation or deployment of one or more inner mechanical thrombectomy devices (s) 110 and their navigation distally to capture and retrieve distal occlusions.

[0029] Figure 7 depicts the preparatory steps in endovascular treatment or procedure for all mechanical thrombectomy devices of the present invention described herein. Typically, upon entry into the body through the femoral artery in the thigh near the groin, a guidewire 755 is navigated through the blood vessel to the target site. Subsequently, a single microcatheter 745 is tracked over the guidewire 755. With the distal end of the single microcatheter 745 properly positioned at the target site within the blood vessel, the guidewire 755 is withdrawn in the proximal direction. While both the single outermost and innermost mechanical thrombectomy devices 105, 110 are in the non - operative / non - deployed state (i.e., radially compressed), a distal - directed force is applied to the proximal shaft 130 to advance the single assembled unit 100 through the single microcatheter 745 to the target site within the blood vessel (Figure 1A).

[0030] When a single microcatheter 745 is withdrawn (i.e., pulled in the proximal direction as depicted by the arrow in FIG. 1B), a single outermost mechanical thrombectomy device 105 is exposed. Due to the memory shape material from which it is manufactured, when exposed from the microcatheter 745, the single outermost mechanical thrombectomy device 105 self-expands radially outward (e.g., the outer diameter / outer shape increases). When actuated / deployed, the single outermost mechanical thrombectomy device 105 physically contacts directly against the inner wall of the blood vessel and anchors it in place (FIG. 1B). In this pre-state, some but not all of the mechanical thrombectomy devices are actuated / deployed (FIG. 1B). Specifically, the single outermost mechanical thrombectomy device 105 is actuated / deployed independently, while the inner mechanical thrombectomy device 110 is maintained in a non-actuated / non-deployed state (i.e., radially constrained / compressed within the inner axial / longitudinal channel 120 of the outermost mechanical thrombectomy device 105).

[0031] With the single outermost mechanical thrombectomy device 105 actuated / deployed and tethered at a predetermined location within a blood vessel, the inner mechanical thrombectomy device 110 is then actuated / deployed independently. This is achieved by the interventionalist applying a distal force to wire 140 attached to the proximal end to expose the inner mechanical thrombectomy device 110 from the outermost mechanical thrombectomy device 105 at its opposite distal end (Figure 1C). Since the inner mechanical thrombectomy device 110 is no longer radially constrained / compressed within the inner axial / longitudinal channel 120 of the outermost mechanical thrombectomy device 105, the actuated / deployed inner thrombectomy device 105 self-expands radially. Continuing its forward movement distally, the actuated / deployed inner thrombectomy device 110 engages the target distal occlusion embedded therein. Following capture, the interventionalist applies a proximal force (e.g., pull) to wire 140 to radially compress the inner mechanical thrombectomy device (along with the captured occlusion therein) such that it returns (i.e., is pulled back) into the inner axial / longitudinal channel 120 of the outermost mechanical thrombectomy device 105. Next, the interventionalist draws the proximal shaft 130 towards and back into the microcatheter 745 while radially compressing (i.e., reducing the outer diameter or outer profile) the outermost mechanical thrombectomy device 105 and the nested inner mechanical thrombectomy device 110 therein. Thus, during retrieving an occlusion captured using the nested mechanical thrombectomy assembly of the present invention, the interventionalist does not sequentially operate or actuate two separate and different mechanical thrombectomy devices using only a single microcatheter, but rather only operates or actuates a single device (i.e., a single assembled unit comprising the nested mechanical thrombectomy assembly).

[0032] The first independent actuation / deployment of the outermost mechanical thrombectomy device 105 may have advantages that outweigh the advantage of functioning as an anchor within the blood vessel while navigating through tortuous paths of the distal blood vessel during deployment of the inner mechanical thrombectomy device 110. This additional advantage is exerted by using the nested mechanical thrombectomy assembly of the present invention during capture of a target occlusion within a bifurcated blood vessel at a bifurcation site (i.e., where a single blood vessel bifurcates into multiple branched blood vessels). FIG. 3A depicts the fully deployed nested mechanical thrombectomy assembly of the present invention at a bifurcation site (i.e., the site where a single blood vessel divides or splits into two or more branched blood vessels). The single outermost mechanical thrombectomy device 105 that is actuated / deployed is moored at a predetermined position proximal to / on the bifurcation site. Next, the subsequent actuation or deployment of the inner mechanical thrombectomy device 110 when exposed from the outermost mechanical thrombectomy device 105 is advanced into one of the bifurcated blood vessels to capture a blood clot therein. FIG. 3B depicts the retrieval of a blood clot embedded within the inner mechanical thrombectomy device 110 that is radially compressed together while being retrieved / pulled back into the inner axial / longitudinal channel 120 of the single outermost mechanical thrombectomy device 105 in response to an operator pulling the wire 140 in the proximal direction. In comparison, FIGS. 4A and 4B illustrate a similar operation using a conventional single-cage mechanical thrombectomy device with a smaller outer diameter at the same bifurcation site. Referring to FIG. 4B, during retrieval using a conventional single-cage mechanical thrombectomy device with a smaller outer diameter, as a result of relatively low juxtaposition with the blood vessel wall, there is an increased risk that the captured blood clot will be released, which, along with any free debris or fragments (f2, f3), may undesirably enter another bifurcated blood vessel at the bifurcation site. However, the independently operable nested mechanical thrombectomy device 100 of the present invention eliminates this potential risk, whereby any free debris or fragments (f1, f2) are captured within the previously actuated / deployed single outermost mechanical thrombectomy device 105 (FIG. 3B) positioned proximal to / on the bifurcation site.

[0033] Since each mechanical thrombectomy device equipped with a nested mechanical thrombectomy assembly is operable independently of each other, in certain situations, it may be desirable to initiate only a partial actuation / partial deployment of less than all of the mechanical thrombectomy devices. For example, either the single outermost mechanical thrombectomy device 105 or the inner mechanical thrombectomy device 110 may never be actuated / deployed (i.e., remain non-actuated / non-deployed). In one such example, the outer thrombectomy device 105 is maintained in a non-actuated / non-deployed state (i.e., radially compressed while being covered within the lumen of the microcatheter 745), and access to its distal occlusion is achieved by actuating / deploying only the inner mechanical thrombectomy device 110 nested therein. Referring again to FIG. 7, typically, when entering the body through the femoral artery in the thigh near the groin, the guidewire 755 is navigated through the blood vessel to the target site. Thereafter, a single microcatheter 745 is tracked over the guidewire 755. With the distal end of the single microcatheter 745 properly positioned at the target site within the blood vessel, the guidewire 755 is withdrawn in the proximal direction. While both the outermost and inner mechanical thrombectomy devices 105, 110 are in a non-actuated / non-deployed state (i.e., radially compressed), a distal force is applied to the proximal shaft 130 to advance the nested mechanical thrombectomy assembly 100 as a single assembled unit through the single microcatheter 745 to the target site within the blood vessel (FIG. 2A). In contrast to FIGS. 1A-1C, the outermost mechanical thrombectomy device 105 in FIGS. 2A-2C is never actuated / deployed. That is, throughout the treatment or procedure, the outermost mechanical thrombectomy device 105 is maintained in a non-actuated / deployed state covered by the lumen 750 of the microcatheter 745. While the outer thrombectomy device 105 is maintained in a non-actuated state covered within the lumen 750 of the microcatheter 745, independently thereof, the inner mechanical thrombectomy device 105 is actuated / deployed to capture and retrieve the distal occlusion.Specifically, to capture the occlusion, the operator applies a force (e.g., pushes) in the distal direction to the wire 140, thereby advancing the inner mechanical thrombectomy device 110 fixed thereto (FIG. 2B). When exiting from the distal end of the inner axial / longitudinal channel 120 of the outer mechanical thrombectomy device 105, the inner mechanical thrombectomy device 110 automatically transitions to an actuated / deployed state (i.e., radially expanded) (FIG. 2B). The actuated / deployed inner mechanical thrombectomy device 110 preferably has an outer diameter / outer profile that is smaller than the outer diameter / outer profile of the non-actuated / non-deployed outermost mechanical thrombectomy device 105, which can navigate through the distal blood vessel having a smaller diameter where the occlusion is located. FIG. 2C shows the actuated / deployed inner mechanical thrombectomy device 110 exposed from the distal end of the microcatheter 745 as it moves through the distal blood vessel until it reaches the occlusion. Following capture, when the non-actuated / non-deployed outermost mechanical thrombectomy device 105, still covered by the microcatheter 745, returns (i.e., is retracted) into the inner axial / longitudinal channel 120, the operator applies a proximal force (e.g., pulls) to the wire 140 to radially compress the inner mechanical thrombectomy device 110 (along with the captured occlusion therein). Next, the operator pulls the proximal shaft 130 in the proximal direction and returns / pulls the outermost mechanical thrombectomy device 105, along with the nested inner mechanical thrombectomy device and the captured blood clot therein, through the microcatheter 745 as a single assembled unit.

[0034] In the exemplary illustrative view of FIG. 2A, note that the nested mechanical thrombectomy assembly, as a single assembled unit, does not advance to the distal end / tip of the microcatheter 745, but rather stops at a predetermined distance in its proximal direction. Thus, in FIG. 2B, when exposed from the outermost mechanical thrombectomy device 105, the inner mechanical thrombectomy device 110 then moves a predetermined distance through the microcatheter 745 while in the actuated / deployed state. As an alternative thereto, the nested mechanical thrombectomy assembly, as a single assembled unit, can be advanced to the distal end of the microcatheter 745, whereby, when exposed from the outermost mechanical thrombectomy device 105, the actuated / deployed inner mechanical thrombectomy device 110 does not need to move through the microcatheter 745.

[0035] The nested mechanical thrombectomy assembly can be specifically configured to be used at a bifurcation site (i.e., where a single blood vessel bifurcates into multiple distal branched blood vessels) to capture tandem distal thrombus formations / obstructions in two or more distal branched blood vessels (Figs. 5A - 5E). Again, a nested mechanical thrombectomy assembly comprising an inner mechanical thrombectomy device 510 nested within the inner axial / longitudinal channel 520 of the outermost mechanical thrombectomy device 505 can be advanced as a single assembled unit through a single microcatheter 745 (configured as an unbranched cylindrical tube) to a target site within a blood vessel. In this particular design, the inner mechanical device 510 comprises two sections, namely, a proximal section 565 (including the proximal end / tip) and a distal section 575 (including the distal end / tip). The proximal section 565 comprises a primary self - expanding cage structure, while the distal section 575 can be branched, split, divided, or separated into two or more axially / longitudinally extending secondary self - expanding cage structures 585a, 585b and can be releasably fixed together (e.g., twisted). In the example depicted in Figs. 5A - 5E, the inner mechanical device 510 has a bifurcated distal section with two secondary self - expanding cage structures 585a, 585b. The proximal ends of each of the secondary self - expanding cage structures 585a, 585b are fixed to or integral with the distal end of the primary self - expanding cage structure 565. Although nested / accommodated within the inner axial / longitudinal channel 520 of the outermost mechanical thrombectomy device 505, the non - operative / undeployed (i.e., radially compressed) secondary self - expanding cage structures 585a, 585b are preferably held together releasably (e.g., twisted) in direct physical contact with each other axially / longitudinally. Then, when the inner mechanical thrombectomy device 510 emerges from the distal end of the outermost mechanical thrombectomy device 505, it automatically activates / deploys. When exposed from the outermost mechanical thrombectomy device 505, the secondary self - expanding cage structures 585a, 585b automatically disengage / releases from each other (e.g., untwist) such that the secondary self - expanding cage structures 585a, 585b no longer have direct physical contact with each other axially / longitudinally.When they separate from each other, the secondary self-expanding cage structures 585a, 585b automatically return to their original radially self-expanding configuration (i.e., the actuated / deployed state).

[0036] In FIGS. 5A-5E, when exposed from the outermost thrombus removal device 505, the secondary self-expanding cage structures 585a, 585b automatically disengage or separate from each other, enabling each to expand radially on its own. Under certain circumstances, it may be beneficial to maintain the secondary self-expanding cage structures 585a, 585b engaged / fixed together even when exposed from the outermost mechanical thrombus removal device. In such cases, disengagement, release, or separation of the secondary cage structures 585a, 585b occurs only in response to a positive action (e.g., pulling a release wire) by an operator at a desired location within the blood vessel.

[0037] A particular design of a nested mechanical thrombus removal assembly comprising two secondary self-expanding cage structures 585a, 585b (FIGS. 5A-5E) is particularly well-suited for capturing thrombi located within one or more branched blood vessels at a bifurcation site, but such an assembly can nevertheless be used to capture a single thrombus within a single unbranched blood vessel (e.g., by fixing and maintaining the secondary self-expanding cage structures together).

[0038] To reach an embolism located in a distal blood vessel, the axial / longitudinal length of the inner mechanical thrombectomy device can be intentionally designed to exceed the length of the inner axial / longitudinal channel 520 of the outermost mechanical thrombectomy device 505 in which it is nested (hereinafter referred to as "extra, extended, or supplemental length"). Before assembly within the inner axial / longitudinal channel 520 of the outermost mechanical thrombectomy device 510, the secondary self-expanding cage structures 585a, 585b of the inner mechanical thrombectomy device 505 are fixed / held together (e.g., twisted) in direct physical contact with each other axially / longitudinally while in a non-activated / undeployed state (i.e., radially compressed). To accommodate the extra, extended, or supplemental axial / longitudinal length of the inner mechanical thrombectomy device 510 within the inner axial / longitudinal channel 520 of the outermost mechanical thrombectomy device 505, the distal portion is folded onto itself. Specifically, while the non-activated / undeployed secondary self-expanding cage structures 585a, 585b are fixed / held together (e.g., twisted), the distal end / tip is pulled back proximally onto itself until the axial / longitudinal length of the inner mechanical thrombectomy device 510 is less than that of the inner axial / longitudinal channel 520 of the outermost mechanical thrombectomy device 505. The inner mechanical thrombectomy device 510 is depicted as having a bifurcated (i.e., split or divided) distal section comprising two secondary self-expanding cage structures 585a, 585b that are releasably fixed together (e.g., twisted) and folded onto itself. Folding the secondary self-expanding cage structures onto itself while fixed together is an optional feature that can be used as desired.

[0039] Figures 5A - 5E depict successive steps in the deployment of the nested mechanical thrombectomy device of the present invention. As an illustrative example, the distal section 575 of the inner mechanical thrombectomy device 510 comprises two secondary self - expanding cage structures 585a, 585b that extend axially / longitudinally. The distal section 575 of the inner mechanical thrombectomy device 510 can be designed to have any number of two or more secondary self - expanding cage structures that extend axially / longitudinally, as desired. Further, between the secondary self - expanding cage structures, the configuration (e.g., number of struts, arrangement, and connection points) can be the same but does not necessarily have to be the same. In the example depicted in Figure 5A, to ensure reaching / capturing the target occlusion(s), the axial / longitudinal length of the inner mechanical device in the actuated / deployed state exceeds the axial / longitudinal length of the inner axial / longitudinal channel 520 of the outermost mechanical thrombectomy device 505. Thus, the non - actuated / non - deployed secondary self - expanding cage structures 585a, 585b are releasably fixed / held together (e.g., twisted together) in direct physical contact with each other axially / longitudinally, but the distal ends / tips are pulled back / folded onto themselves in the proximal direction so that the extra length does not exceed the length of the inner axial / longitudinal channel 520 of the outermost mechanical thrombectomy device 505 (hereinafter referred to as the "folded - back portion").

[0040] As described above with respect to the previous embodiments of the present invention, the guide wire 755 is first navigated through the blood vessel to the target site, e.g., a bifurcation site. Next, a single microcatheter 745 (having a non-branched cylindrical tube configuration) having a lumen 750 is tracked over the guide wire 755. Thereafter, the guide wire 755 is withdrawn proximally from the microcatheter 745 remaining at a predetermined location within the blood vessel. The outermost mechanical thrombectomy device 505 and the inner mechanical thrombectomy device 510 nested therein are each in a non-activated / undeployed state, but the nested mechanical thrombectomy assembly is advanced as a single assembled unit through the lumen 750 of the microcatheter 745 to the proximal side / surface of the target bifurcation site (FIG. 5A). Next, the microcatheter 745 is withdrawn proximally to expose the outermost mechanical thrombectomy device 505, which automatically expands radially, while the inner mechanical thrombectomy device 510 nested therein remains non-activated / undeployed (i.e., radially compressed), and the distal portion of the distal section is pulled back / folded over itself (FIG. 5B). As mentioned previously, the folded section 580 of the inner mechanical thrombectomy device 505 is optionally used in situations where the axial / longitudinal extra / extended length provided to reach / capture the occlusion(s) within the distal branched blood vessel is not accommodated within the inner axial / longitudinal channel 520 of the outermost mechanical thrombectomy device 510.

[0041] When the wire 540 is pushed in the proximal direction, the inner mechanical thrombectomy device 510 emerges from the distal end of the outermost mechanical thrombectomy device 505. Once exposed from the outermost mechanical thrombectomy device 505, the folded distal section 580 of the inner mechanical thrombectomy device 510 made of shape memory material automatically returns to its original unfolded / expanded configuration (i.e., is fully extended axially / longitudinally) (Figure 5C). Once exposed and unfolded / expanded, the secondary self-expanding cage structures 585a, 585b expand radially (Figure 5C). Next, the secondary self-expanding cage structures 585a, 585b disengage or separate, either automatically (e.g., by unwinding a twist) or in response to a positive action by the intervenor (e.g., disengaging by pulling on a release wire), and return to their original configuration that is branched, divided, split, or separated from each other (e.g., V-shaped, fork-shaped, extended fingers, etc.) (Figure 5D). At this point, the separated secondary self-expanding cage structures 585a, 585b are simultaneously advanced distally into their respective branch vessels, where they are aligned in series to capture the distal occlusion (Figure 5E). Again, any removed debris or fragments of the blood clot can be captured by the activated / deployed outermost mechanical thrombectomy device 505 disposed proximal to / at the face of the bifurcation site.

[0042] Distal embolization within two or more branched blood vessels at a bifurcation site can be retrieved and captured in series using a specifically designed branched microcatheter 745' that includes a proximal single tubular structure 745'a that is integral with or fixed to a branched distal section having two or more separable branched tubular structures 745'b (Figs. 6A - 6D). Each tubular structure 745'a, 745'b has its own associated lumen that is in fluid communication with each other at the interface where they come together. In Figs. 6A - 6D, the branched distal section includes two separable branched tubular structures 745'b arranged in a Y - shaped or V - shaped configuration. However, the branched distal section of the microcatheter can be modified to include more than two separable branched tubular structures, as desired, with each branched tubular structure having its own associated lumen that is in fluid communication with each other at the interface with the proximal single tubular structure. The branched microcatheter is used to deliver a mechanical thrombectomy device to a blood vessel bifurcation site, and its distal section branches, divides, splits, or separates into a plurality of secondary self - expanding cage structures.

[0043] In use, the guidewire 755 is first navigated through the blood vessel to a position proximal to / above the branch site on the side. The separate branched tubular structures 745'b are preferably fixedly attached together releasably, enabling the branched microcatheter 745' to be tracked unobstructed over the guidewire 755 to the target branch site. Thereafter, the guidewire 755 is withdrawn proximally from the branched microcatheter 745' remaining at a predetermined location within the blood vessel. Next, the branched tubular structures 585a, 585b of the branched microcatheter 745' are released, enabling them to return to their original branched, split, divided, or separated state. Each branched tubular section 745'b of the microcatheter can be held together by any type of releasable fixation mechanism (e.g., via a mechanical latch device that unlatches when twisted or when subjected to a pulling force in the proximal direction by the intervenor). When released, each branched tubular section 745'b of the branched microcatheter 745' returns to its original separated configuration. Further pushing in the proximal direction simultaneously advances the separated branched tubular structures 745'b of the microcatheter 745' together into their respective branched blood vessels (as depicted in FIG. 6A).

[0044] Next, the mechanical thrombus removal device is introduced into the proximal end of the bifurcated microcatheter 745' while the secondary self-expanding cage structures 585a, 585b are fixed together (e.g., by a twisted or mechanical latch mechanism). Before reaching the separated bifurcated tubular structure 745'b of the microcatheter 745', the secondary self-expanding cage structures 585a, 585b of the mechanical thrombus removal device are released (e.g., in response to an active action by an intervenor such as pulling a wire, untwisting or releasing a mechanical latch mechanism) to return to their original separated arrangement (FIG. 6B). By continuously pushing the mechanical thrombus removal device distally via a pull wire, the separated secondary self-expanding cage structures 585a, 585b are exposed from the bifurcated tubular structure 745'b of the microcatheter into the associated bifurcated blood vessels (FIG. 6C). In FIG. 6C, when their distal portions of the secondary self-expanding cage structures 585a, 585b emerge from the distal end / tip of each bifurcated tubular structure 745'b of the microcatheter, they automatically expand radially and capture the blood clots in each of the bifurcated blood vessels in tandem. The secondary self-expanding cage structures with the blood clots captured therein are simultaneously pulled back into each of the bifurcated tubular sections 745'b of the microcatheter 745'. Finally, in FIG. 6D, the microcatheter 745' is withdrawn from the blood vessel together with the mechanical thrombus removal device and the blood clots captured therein. As illustrated in FIGS. 6A-6D, on the proximal side / face of the bifurcation site, each of the secondary self-expanding cage structures 585a, 585b automatically activates / deploys (i.e., expands radially) when exposed from each of the bifurcated tubular structures 745'b of the microcatheter 745'. Alternatively, the secondary self-expanding cage structures 585a, 585b may cross / intersect the blood clots before being activated / deployed in response to an active action by an intervenor (e.g., pulling a wire to release a locking mechanism).

[0045] The final configuration shown in FIGS. 10A and 10B depicts the capture and retrieval of distal emboli in two or more branch vessels at a vertical column bifurcation site. Similar to those in FIGS. 6A-6D, the mechanical thrombectomy device of the present invention in FIGS. 10A and 10B includes a proximal section 565' having a primary self-expanding cage structure with a distal section that is branched, divisible, splittable or separable into a plurality of secondary self-expanding cage structures 585'a, 585'b. Again, the distal section of the exemplary mechanical thrombectomy device in FIGS. 10A and 10B branches into two secondary self-expanding cage structures, although more than two secondary self-expanding cage structures are also possible. Instead of the branched microcatheter 745' used in FIGS. 6A-6D, in FIGS. 10A and 10B, a single microcatheter 745 having a non-branched single tube configuration is used to deliver the mechanical thrombectomy device to the target site within the blood vessel. The secondary self-expanding cage structures 585'a, 585'b in FIGS. 10A and 10B are releasably fixed together (e.g., twisted) so as to allow unobstructed advancement when tracked through the microcatheter 745. When exposed from the microcatheter 745, the secondary self-expanding cage structures 585'a, 585'b automatically separate (e.g., unwind the twist), such that each can be advanced across the clot in its respective branch vessel. Alternatively, the release or separation of the self-expanding cage structures 585'a, 585'b can be in response to some positive action by the operator (e.g., pulling a release wire in the proximal direction). While in the position to cross the clot, the secondary self-expanding cage structures 585'a, 585'b are actuated / deployed in response to a positive action by the operator (e.g., pulling a deployment wire in the proximal direction) to capture that portion of the clot in its respective branch vessel, as shown in FIG. 10B. Preferably, the proximal primary self-expanding cage structure 565' is also exposed from the microcatheter 745 and actuated / deployed (automatically when exposed from the microcatheter or in response to a positive action by the operator such as pulling a wire) to capture that portion of the clot disposed proximal to / on the face of the bifurcation site and debris / fragments from the captured clot therein.During retrieval, the mechanical thrombectomy device, along with the captured blood clot therein, is withdrawn and returned into the microcatheter 745.

[0046] The distal sections of the inner mechanical thrombectomy devices of FIGS. 5A-5E, as well as the distal sections of the mechanical thrombectomy devices of FIGS. 6A-6D and 10A-10B, each comprise two secondary self-expanding cage structures. However, any desired number of two or more secondary self-expanding cage structures is possible. Further, the plurality of secondary self-expanding cage structures can advance distally into each of the branched blood vessels at the branch site and capture the occlusions therein in series. For delivery of the mechanical thrombectomy device configured as a nested mechanical thrombectomy assembly, various configurations for capture and retrieval of distal occlusions at the vascular branch site have been illustrated and described using a single microcatheter having a plurality of branched lumens or a single microcatheter having a non-branched cylindrical tube configuration. Any particular feature in any one configuration of the mechanical thrombectomy device illustrated and described above can be used in any other configuration or embodiment.

[0047] Accordingly, while the basic novel features of the present invention as applied to the preferred embodiments of the present invention have been illustrated, described, and pointed out, it will be understood by those skilled in the art that various omissions, substitutions, and changes in the form and details of the illustrated system / devices, as well as in their operation, can be made without departing from the spirit and scope of the present invention. For example, it is clearly intended that all combinations of elements and / or steps that perform substantially the same function in substantially the same way to achieve the same result are included within the scope of the present invention. Substitution of elements from one described embodiment to another is also fully intended and within the scope of what is contemplated. It should also be understood that the drawings are not necessarily drawn to scale and are merely conceptual. Accordingly, it is intended to be limited only by what is indicated by the appended claims.

[0048] All issued patents, pending patent applications, publications, papers, books, or other references cited are hereby incorporated by reference in their entirety into this specification, each as if set forth herein in full.

[0049] 〔Embodiments〕 (1) A nested mechanical thrombectomy assembly deliverable as a single assembled unit, comprising: The outermost mechanical thrombectomy device operable from a radially compressed state to a radially expanded state, forming an axially extending inner channel; and A proximal shaft having a lumen extending axially therethrough, the distal end of the proximal shaft being connected to the proximal end of the outermost mechanical thrombectomy device such that the inner channel communicates with the lumen of the proximal shaft; and At least one inner mechanical thrombectomy device operable from a radially compressed state to a radially expanded state, the at least one inner mechanical thrombectomy device being disposed within the inner channel of the outermost mechanical thrombectomy device in the radially compressed state; and A wire extending through the lumen of the proximal shaft and connected to the proximal end of the at least one inner mechanical thrombectomy device. The nested mechanical thrombectomy assembly, wherein each of the outermost mechanical thrombectomy device and the at least one inner mechanical thrombectomy device is operable independently of the other. (2) The nested mechanical thrombectomy assembly according to Embodiment 1, wherein the at least one inner mechanical thrombectomy device comprises a plurality of inner thrombectomy devices disposed within the inner channel of the outermost mechanical thrombectomy device. (3) The nested mechanical thrombectomy assembly according to Embodiment 2, wherein the plurality of inner thrombectomy devices are arranged (i) parallel to each other within the inner channel of the outermost mechanical thrombectomy device, or (ii) concentrically within the inner channel of the outermost mechanical thrombectomy device. (4) The nested mechanical thrombectomy assembly according to Embodiment 1, wherein the at least one inner mechanical thrombectomy device further comprises a proximal section and a distal section, the proximal section being a single primary self-expanding cage structure, and the distal section being a plurality of secondary self-expanding cage structures that are connected to each other only at the interface with the single primary self-expanding cage structure and are directly physically in contact and releasably fixable together, and each of the single primary self-expanding cage structure and the plurality of secondary self-expanding cage structures is operable from a radially compressed state to a radially expanded state. (5) The nested mechanical thrombectomy assembly according to Embodiment 1, further comprising a mechanical restraint device comprising (i) a fixing ring that applies a predetermined force to the wire crimped around the proximal shaft and disposed therein, or (ii) an auxiliary wire that connects the outermost mechanical thrombectomy device and the at least one inner mechanical thrombectomy device.

[0050] (6) The nested mechanical thrombectomy assembly according to Embodiment 1, wherein the at least one inner mechanical thrombectomy device disposed within the inner channel of the outermost mechanical thrombectomy device has a distal section that is folded back proximally on itself. (7) A mechanical thrombectomy device, A mechanical thrombectomy device comprising a proximal section and a distal section, wherein the proximal section is a single primary self-expanding cage structure, and the distal section is a plurality of secondary self-expanding cage structures that are connected to each other and in direct physical contact and releasably fixable only at the interface with the single primary self-expanding cage structure, and each of the single primary self-expanding cage structure and the plurality of secondary self-expanding cage structures is operable from a radially compressed state to a radially expanded state. (8) A branched microcatheter, comprising a proximal section having a single tubular structure that is integral with or fixed to a branched distal section having a plurality of separate branched tubular structures, and the single tubular structure of the proximal section and each of the plurality of separate branched tubular structures of the branched distal section have associated lumens that are in fluid communication with each other at the interface between the proximal section and the branched distal section. (9) A method for using a nested mechanical thrombectomy assembly, the nested mechanical thrombectomy assembly comprising an outermost mechanical thrombectomy device operable to move from a radially compressed state to a radially expanded state, the outermost mechanical thrombectomy device forming an axially extending inner channel, a proximal shaft having a lumen extending axially therethrough, the distal end of the proximal shaft being connected to the proximal end of the outermost mechanical thrombectomy device such that the inner channel communicates with the lumen of the proximal shaft, at least one inner mechanical thrombectomy device operable to move from a radially compressed state to a radially expanded state, the at least one inner mechanical thrombectomy device being disposed within the inner channel of the outermost mechanical thrombectomy device, and a wire disposed within the lumen of the proximal shaft and connected to the proximal end of the at least one inner mechanical thrombectomy device, each of the outermost mechanical thrombectomy device and the at least one inner mechanical thrombectomy device being operable independently of each other, the method comprising navigating a guide wire through a blood vessel to a target site; tracking a single microcatheter over the guide wire; withdrawing the guide wire proximally from the single microcatheter; advancing the nested mechanical thrombectomy assembly through the single microcatheter while each of the single outermost mechanical thrombectomy device and the at least one inner mechanical thrombectomy device is in the radially compressed state; capturing at least one occlusive substance within the nested mechanical thrombectomy assembly by independently operating (i) the single outermost mechanical thrombectomy device and / or (ii) the at least one inner mechanical thrombectomy device; A method comprising the step of simultaneously withdrawing the single microcatheter and the nested mechanical thrombus removal assembly from the blood vessel, together with the at least one occlusion captured therein. (10) The capturing step comprises independently actuating the single outermost mechanical thrombus removal device when it is exposed from the single microcatheter withdrawn in the proximal direction while the at least one inner mechanical thrombus removal device remains non-operational, the actuated single outermost thrombus removal device transitioning to the radially expanded state where it is physically in direct contact with and tethered to a predetermined location on the inner wall of the blood vessel, the method according to embodiment 9.

[0051] (11) The at least one inner mechanical thrombus removal device is never actuated and is maintained in the radially compressed state disposed within the inner channel of the outermost mechanical thrombus removal device, and the at least one occlusion is captured within the actuated single outermost mechanical thrombus removal device, the method according to embodiment 10. (12) The capturing step further comprises independently actuating the at least one inner mechanical thrombus removal device to capture the at least one occlusion therein when it is advanced distally out of the inner channel of the single outermost mechanical thrombus removal device following actuation of the single outermost mechanical thrombus removal device tethered to a predetermined location within the blood vessel, the method according to embodiment 10. (13) The capturing step comprises independently actuating the at least one inner mechanical thrombus removal device to capture the at least one occlusion therein when it is advanced distally out of the inner channel of the single outermost mechanical thrombus removal device while the outermost mechanical thrombus removal device is never actuated, the method according to embodiment 9. (14) The method according to embodiment 9, wherein the at least one inner mechanical thrombectomy device is at least two inner mechanical thrombectomy devices disposed within the inner channel of the outermost mechanical thrombectomy device. (15) The method according to embodiment 14, wherein the at least two inner mechanical thrombectomy devices are arranged (i) parallel to each other within the inner channel of the outermost mechanical thrombectomy device, or (ii) concentrically within the inner channel of the outermost mechanical thrombectomy device.

[0052] (16) The target site is at a bifurcation site where a single blood vessel bifurcates into a plurality of branched blood vessels, and the capturing step comprises independently actuating the single outermost mechanical thrombectomy device exposed from the single microcatheter withdrawn in the proximal direction to transition to the radially expanded state in which it is directly physically contacted with and moored at a predetermined location against the inner wall of the single blood vessel proximal to the bifurcation site; while the single outermost mechanical thrombectomy device is independently actuated and moored at a predetermined position, independently actuating the at least one inner mechanical thrombectomy device advanced distally from the inner channel of the single outermost mechanical thrombectomy device into one of the plurality of branched blood vessels to capture the at least one occlusive substance by the actuated at least one inner mechanical thrombectomy device; capturing any fragments of the at least one occlusive substance within the actuated single outermost mechanical thrombectomy device during the step of withdrawing the nested mechanical thrombectomy assembly. The method according to embodiment 9. (17) While in the radially compressed state within the inner channel of the single outermost mechanical thrombectomy device, the at least one inner mechanical thrombectomy device has a distal portion folded proximally over itself, and the step of actuating includes actuating the at least one inner mechanical thrombectomy device when exposed from the inner channel of the single outermost mechanical thrombectomy device so that the distal portion folded proximally over itself is expanded distally. The method according to embodiment 9. (18) The step of actuating includes overcoming a predetermined restraining force that prevents unintentional actuation of the nested mechanical thrombectomy assembly, the predetermined restraining force being generated by a mechanical restraint device comprising (i) a fixing ring that crimps around the proximal shaft and applies a predetermined force to the wire disposed therein, or (ii) an auxiliary wire connecting the outermost mechanical thrombectomy device and the at least one inner mechanical thrombectomy device. The method according to embodiment 9. (19) A method for capturing a blood clot within a blood vessel, navigating a guide wire through the blood vessel to a bifurcation site where a single blood vessel bifurcates into a plurality of branched blood vessels; tracking a single microcatheter over the guide wire to the bifurcation site, the single microcatheter comprising a proximal section having a single lumen and a branched distal section having a plurality of branched lumens, and while tracking over the guide wire, the plurality of separate branched lumens of the branched distal section of the single microcatheter being releasably fixed together; tracking; pulling the guide wire proximally out of the single microcatheter; enabling the plurality of branched lumens of the branched distal section of the single microcatheter to be released and separated; Advancing, in a distal direction and simultaneously within the respective branched blood vessels at the branching site, the plurality of separated branched lumens of the branched distal section of the single microcatheter; Advancing, through the single microcatheter, a mechanical thrombectomy device including a proximal section and a distal section to a position proximal to the branched distal section, wherein the proximal section is a single primary self-expanding cage structure, the distal section is a plurality of secondary self-expanding cage structures that are connected to each other only at an interface with the primary self-expanding cage structure, and the plurality of secondary self-expanding cage structures are axially directly physically contactable and releasably fixable together while advancing through the single microcatheter to the branched distal section; Enabling the release and separation of the plurality of secondary self-expanding cage structures of the mechanical thrombectomy device while the branched distal section of the single microcatheter is positioned proximal thereto; Advancing the plurality of separate secondary self-expanding cage structures of the mechanical thrombectomy device in a distal direction and inserting them into respective ones of the plurality of separated branched lumens of the branched distal section of the single microcatheter positioned in the respective branched blood vessels at the branching site; Actuating the plurality of separate secondary self-expanding cage structures exposed from respective ones of the separate branched lumens of the branched distal section of the single microcatheter and, in the actuated plurality of separate secondary self-expanding cage structures, transversely crossing and capturing at least one occlusive substance disposed in the branched blood vessels at the branching site in series; Retracting the plurality of secondary self-expanding cage structures, together with the at least one occlusive substance captured therein, into the branched lumen of the single microcatheter; A method comprising simultaneously withdrawing the branched microcatheter and the mechanical thrombectomy device, together with the occlusive substance captured therein, in the proximal direction. (20) A method for capturing a blood clot within a blood vessel, comprising: navigating a guide wire through the blood vessel to a bifurcation site where a single blood vessel branches into a plurality of branch vessels; tracking a single microcatheter along the guide wire to the bifurcation site; withdrawing the guide wire proximally from the single microcatheter; advancing, through the single microcatheter, a mechanical thrombectomy device including a proximal section and a distal section, wherein the proximal section is a single primary self-expanding cage structure and the distal section is a plurality of secondary self-expanding cage structures that are connected to each other only at an interface with the primary self-expanding cage structure, and wherein the plurality of secondary self-expanding cage structures are directly physically contactable and releasably fixable together while advancing through the single microcatheter; enabling the plurality of secondary self-expanding cage structures to be released and separated; advancing, in a distal direction, each of the plurality of separate secondary self-expanding cage structures into a respective one of the plurality of branch vessels at the bifurcation site that traverses at least one occlusion; actuating the single primary self-expanding cage structure and the plurality of separate secondary self-expanding cage structures exposed from the single microcatheter to capture the at least one occlusion therein in series; retracting the single primary self-expanding cage structure and the plurality of secondary self-expanding cage structures, together with the at least one occlusion captured therein, into the single microcatheter; withdrawing the single microcatheter and the mechanical thrombectomy device, together with the at least one occlusion captured therein, in the proximal direction, either simultaneously or sequentially.

Claims

**Claim 1** A nested mechanical thrombectomy assembly that can be delivered as a single assembled unit, The outermost mechanical thrombectomy device that can be actuated from a radially compressed state to a radially expanded state, forming an axially extending inner channel, the outermost mechanical thrombectomy device, A proximal shaft having a lumen that extends axially through the interior, the distal end of the proximal shaft being connected to the proximal end of the outermost mechanical thrombectomy device such that the inner channel communicates with the lumen of the proximal shaft, the proximal shaft, At least one inner mechanical thrombectomy device that can be actuated from a radially compressed state to a radially expanded state, in the radially compressed state, the at least one inner mechanical thrombectomy device being disposed within the inner channel of the outermost mechanical thrombectomy device, at least one inner mechanical thrombectomy device, A wire that extends through the lumen of the proximal shaft and is connected to the proximal end of the at least one inner mechanical thrombectomy device, and A nested mechanical thrombectomy assembly in which each of the outermost mechanical thrombectomy device and the at least one inner mechanical thrombectomy device can be actuated independently of each other. **Claim 2** The nested mechanical thrombectomy assembly according to claim 1, wherein the at least one inner mechanical thrombectomy device comprises a plurality of inner thrombectomy devices disposed within the inner channel of the outermost mechanical thrombectomy device. **Claim 3** The nested mechanical thrombectomy assembly according to claim 2, wherein the plurality of inner thrombectomy devices are arranged (i) parallel to each other within the inner channel of the outermost mechanical thrombectomy device, or (ii) concentrically within the inner channel of the outermost mechanical thrombectomy device. **Claim 4** The nested mechanical thrombectomy assembly of claim 1, wherein the at least one inner mechanical thrombectomy device further comprises a proximal section and a distal section, the proximal section being a single primary self-expanding cage structure, the distal section being a plurality of secondary self-expanding cage structures that are connected to each other and directly physically contact only at the interface with the single primary self-expanding cage structure and are releasably fixable together, and each of the single primary self-expanding cage structure and the plurality of secondary self-expanding cage structures is operable from a radially compressed state to a radially expanded state.

5. The nested mechanical thrombectomy assembly of claim 1, further comprising a mechanical restraint device comprising (i) a fixing ring that presses against the proximal shaft and applies a predetermined force to the wire disposed therein, or (ii) an auxiliary wire that connects the outermost mechanical thrombectomy device and the at least one inner mechanical thrombectomy device.

6. The nested mechanical thrombectomy assembly of claim 1, wherein the at least one inner mechanical thrombectomy device disposed in the inner channel of the outermost mechanical thrombectomy device has a distal section folded proximally onto itself.

7. A mechanical thrombectomy device, comprising a proximal section and a distal section, the proximal section being a single primary self-expanding cage structure, the distal section being a plurality of secondary self-expanding cage structures that are connected to each other and directly physically contact only at the interface with the single primary self-expanding cage structure and are releasably fixable together, and each of the single primary self-expanding cage structure and the plurality of secondary self-expanding cage structures is operable from a radially compressed state to a radially expanded state.

8. A bifurcated microcatheter, A branched microcatheter comprising a proximal section having a single tubular structure that is integral with or fixed to a branched distal section having a plurality of separate branched tubular structures, wherein the single tubular structure of the proximal section and each of the plurality of separate branched tubular structures of the branched distal section have associated lumens that are in fluid communication with each other at an interface between the proximal section and the branched distal section.

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