Patent Description:
When a thrombus is formed in a blood vessel, blood becomes difficult to flow to a periphery side of the thrombus. This prevents oxygen and nutrition from sufficiently reaching the periphery, and there is a danger of necrosis of a cell tissue that has become depleted of oxygen. Therefore, for example, PTL <NUM> describes a device that aspirates and removes thrombi by a sheath connected to an aspirating pump. This device is provided with a separator that can protrude from a tip opening of the sheath. The separator is provided to a distal portion of a wire that penetrates through the sheath, and has an outer diameter larger than that of the wire. An operator causes the separator to protrude from the tip opening of the sheath and moves the separator in the front-back direction to allow the thrombi to be led into the sheath.

PTL <NUM> and PTL <NUM> disclose further prior art thrombus removal devices with rearward cutting members.

However, in a case where a thrombus is hard and large, the device described in PTL <NUM> cannot lead the thrombus into the sheath.

This invention is made in order to solve the above-described problem, and an object thereof is to provide a removal device and a removal system that can effectively remove an object in a body lumen while suppressing damage to another device.

The above mentioned problem is solved by a removal device according to claim <NUM> and a removal system according to claim <NUM>, with further embodiments disclosed by the dependent claims.

The removal device includes at least an elongated shaft part, and an cutting part that is fixed to a distal portion of the shaft part, in which a proximal portion of the cutting part includes a ring-shaped cutting blade, and a surface on which the cutting blade is positioned is inclined relative to a center axis of the shaft part at an angle of less than <NUM> degrees.

The removal system includes a sheath with a lumen being formed on which an aspiration force is caused to act; and a removal device capable of inserting into the sheath, in which the removal device includes at least: an elongated shaft part; and a cutting part that is fixed to a distal portion of the shaft part, a proximal portion of the cutting part includes a ring-shaped cutting blade, and a surface on which the cutting blade is positioned is inclined relative to a center axis of the shaft part at an angle of less than <NUM> degrees.

The removal device and the removal system configured as claimed in claims <NUM> and <NUM> insert the cutting part into the body lumen and then pull the shaft part to allow the cutting blade to cut an object in the body lumen. The cutting blade having a ring shape receives a part of an object having a three-dimensional shape in an inside of the ring, and is thus easy to be caught by the object. Therefore, the removal device and the removal system can effectively cut and remove the object by the cutting blade that is difficult to slip with respect to the object. The surface on which the cutting blade is positioned is inclined relative to the center axis of the shaft part at an angle of less than <NUM> degrees, so that the cutting blade is difficult to damage another device, for example, the sheath, when moving to the proximal side.

Hereinafter, embodiments of this disclosure will be described with reference to the drawings. Note that, the size ratios in the drawings may be exaggerated for convenience of explanation, and may be different from the actual ratios in some cases.

A removal system <NUM> according to a first embodiment of this invention is used to aspirate and remove an object such as a thrombus, a plaque, or a calcified lesion in a blood vessel. Note that, in the present description, a side of the device to be inserted into a blood vessel is referred to as a "distal side", and a hand-side where the device is operated is referred to as a "proximal side". Moreover, an object to be removed is not necessarily limited to a thrombus, a plaque, or a calcified lesion, but all the objects that can exist in a body lumen can be corresponded. Moreover, in the present description, a source side of a flow in the blood vessel is referred to as an "upstream side", and a side toward which the flow of blood is headed is referred to as a "downstream side".

The removal system <NUM> is provided with a removal device <NUM> that cuts an object in the blood vessel, and a sheath <NUM> capable of storing therein the removal device <NUM>, as illustrated in <FIG>. The removal device <NUM> is provided with an elongated shaft part <NUM>, and a main cutting body <NUM> that is fixed to a distal portion of the shaft part <NUM>.

The shaft part <NUM> is an elongated wire that extends from a hand side to the main cutting body <NUM>. The distal portion of the shaft part <NUM> is fixed to the main cutting body <NUM>.

A constituent material for the shaft part <NUM> is not specially limited but preferably has a tensile strength to some extent, and for example, stainless steel, a shape memory alloy, and the like can be suitably used. As for a shape memory alloy, Ni-Ti-based, Cu-Al-Ni-based, Cu-Zn-Al-based shape memory alloys, combinations thereof, and the like are preferably used. The shaft part <NUM> is not limited to a solid wire, but may be a hollow tubular body, for example.

The main cutting body <NUM> is an approximately cylindrical member having an outer diameter larger than that of the shaft part <NUM>. In the main cutting body <NUM>, a concave portion <NUM> that is closed at the distal side and is opened toward the proximal side is formed. An end portion on the proximal side of the main cutting body <NUM> includes a slope <NUM> that is inclined at an angle θ of less than <NUM> degrees relative to a center axis X of the shaft part <NUM>. In other words, a proximal portion of the main cutting body <NUM> has a shape in which a cylinder having an inner diameter and an outer diameter that are constant in an axial direction is obliquely cut. The inclined angle θ exceeds <NUM> degrees and less than <NUM> degrees, is preferably between <NUM> degrees and <NUM> degrees, and is more preferably between <NUM> degrees and <NUM> degrees. The main cutting body <NUM> and the shaft part <NUM> are arranged such that a site that is positioned at the most proximal side of the slope <NUM> is adjacent to the shaft part <NUM>. In the concave portion <NUM>, the slope <NUM> is opened. A ring-shaped site that surrounds the concave portion <NUM> of the slope <NUM> forms a cutting part <NUM>. The cutting part <NUM> includes an outer edge <NUM> that is positioned at an outer peripheral surface side of the main cutting body <NUM>, and an inner edge <NUM> that is positioned at an inner peripheral surface side thereof. The outer edge <NUM> and/or the inner edge <NUM> functions as a sharp cutting blade. Accordingly, the slope <NUM> is a surface on which the cutting blade is positioned. An end portion on the distal side of the main cutting body <NUM> includes a distal surface <NUM>. An outer peripheral portion 28A that is positioned radially outward of the distal surface <NUM> is subjected to curved surface processing, and is smoothly connected to an outer peripheral surface of the main cutting body <NUM>. The shape of the ring of the slope <NUM> may be an ellipse or a circle. A part of the surface (surface sandwiched between the outer edge and the inner edge) of the ring may be partially thinned.

The outer peripheral surface of the main cutting body <NUM> is fixed to the shaft part <NUM> by a fixing part <NUM>. The fixing part <NUM> is formed, for example, by welding, soldering, brazing, an adhesive, or the like. The shaft part <NUM> is fixed to a position spaced in the radial direction from a center axis Y of the main cutting body <NUM> and the cutting part <NUM>. Note that, the shaft part <NUM> does not need to be fixed to the outer peripheral surface of the main cutting body <NUM>. For example, the shaft part <NUM> may be fixed to an inner peripheral surface of the main cutting body <NUM>. Alternatively, the shaft part <NUM> may be fitted into a fitting hole (not illustrated) that is formed in the slope <NUM> of the main cutting body <NUM> toward the distal side. In this case, the shaft part <NUM> is positioned between the inner peripheral surface and the outer peripheral surface of the main cutting body <NUM>. When the fixing part <NUM> abuts on a distal surface of the sheath <NUM>, the cutting part <NUM> is positioned outward in a radial direction of the sheath <NUM>. At this time, the contact with the distal surface of the sheath <NUM> can be further reduced with the fixing part <NUM>. Accordingly, the cutting part <NUM> can be smoothly led into a lumen (a lumen <NUM>, which is described later) of the sheath <NUM>.

A constituent material for the main cutting body <NUM> is preferably hard to the extent that makes it difficult to damage a biological tissue, such as a blood vessel wall, and the sheath <NUM> and allows an object such as a thrombus to be cut, and for example, engineering plastics such as polyether ether ketone (PEEK), polyamide (PA), polycarbonate (PC), polysulfone (PSU), and polyamideimide (PAI) can be suitably used.

The sheath <NUM> is provided with a sheath main body <NUM>, a hub <NUM>, and an anti-kink protector <NUM>, as illustrated in <FIG>. The sheath main body <NUM> is provided with the lumen <NUM> capable of accommodating therein the removal device <NUM>. The sheath main body <NUM> includes a sheath opening portion <NUM> in an end portion on the distal side. The hub <NUM> is fixed to an end portion on the proximal side of the sheath main body <NUM>. The hub <NUM> is provided with a hub opening portion <NUM> that communicates with the lumen <NUM>. The hub opening portion <NUM> can be connected with an aspirating device that generates an aspiration force via a Y connector (not illustrated) or the like. The aspirating device is, for example, a syringe, a pump, or the like. The hub opening portion <NUM> is connected with the Y connector to allow the aspirating device in a state of an elongated device (for example, the shaft part <NUM>) being inserted to be connected thereto. Moreover, the hub opening portion <NUM> can also be connected with a syringe, the Y connector, or the like with which a thrombolytic agent and the like are supplied. The anti-kink protector <NUM> is a flexible member that covers an interlock site of the sheath main body <NUM> and the hub <NUM>. The anti-kink protector <NUM> suppresses a kink of the sheath main body <NUM>.

A constituent material for the sheath main body <NUM> is not specially limited, and for example, polyolefin such as polyethylene, polypropylene, ethylene-propylene copolymer, or ethylene-vinyl acetate copolymer, polyvinyl chloride, polystyrene, polyamide, polyimide, or a combination thereof can be suitably used. The sheath main body <NUM> may include a plurality of materials, or a reinforcing member such as a wire rod may be embedded therein.

Next, a use method of a removal device <NUM> according to the present disclosure will be described using a case where a thrombus (object) in a blood vessel (body lumen) is aspirated and removed as an example. Methods of using the removal device or removal system do not form part of the claimed invention.

Firstly, an operator percutaneously inserts an introducer sheath (not illustrated) into a blood vessel, at the upstream side (proximal side) from a thrombus in the blood vessel. Next, the operator inserts a guide wire (not illustrated) into the blood vessel through this introducer sheath. Subsequently, the operator inserts a proximal side end portion of the guide wire that is positioned in outside the body into the sheath opening portion <NUM> of the sheath <NUM>. Subsequently, the operator causes the sheath <NUM> to reach the vicinity of the thrombus while causing the guide wire to go ahead.

Subsequently, the operator extracts the guide wire from the sheath <NUM>. Subsequently, the operator connects the Y connector to the hub opening portion <NUM>, and inserts the removal device <NUM> from the hub opening portion <NUM> to the lumen <NUM>. Subsequently, the operator operates the shaft part <NUM> that is positioned in outside the body to move the main cutting body <NUM> to the distal side, as illustrated in <FIG>.

Subsequently, the operator operates the shaft part <NUM> that is positioned in outside the body to protrude the main cutting body <NUM> from the sheath <NUM>. Note that, in order to cause the removal device <NUM> to reach a distal side of a thrombus <NUM>, a separately prepared support catheter can also be used.

Subsequently, the operator operates the shaft part <NUM> to alternately move the main cutting body <NUM> to the distal side and to the proximal side along the blood vessel. When the main cutting body <NUM> moves to the distal side, as illustrated in <FIG>, the smooth outer peripheral portion 28A comes into contact with the thrombus <NUM>. Therefore, the main cutting body <NUM> can excellently move in a clearance of the thrombus <NUM> to the distal side. When the main cutting body <NUM> moves to the proximal side, as illustrated in <FIG>, the cutting part <NUM> comes into contact with the thrombus <NUM>. The cutting part <NUM> having a ring shape receives a part of the thrombus <NUM> having a three-dimensional shape in an inside thereof, and is thus easy to be caught by the thrombus <NUM>. Therefore, the outer edge <NUM> and/or the inner edge <NUM> that each functions as a cutting blade of the cutting part <NUM> becomes difficult to slip with respect to the thrombus <NUM>, and can effectively cut the thrombus <NUM>. In particular, the inner edge <NUM> that configures the cutting blade in the cutting part <NUM> that is provided at a position distant from the shaft part <NUM> (a position at an opposite side in the peripheral direction) is effectively caught with respect to the thrombus <NUM>, and can effectively cut the thrombus <NUM>. Cut thrombi <NUM> float in the blood vessel. Subsequently, the aspirating device that is connected to the hub opening portion <NUM> via the Y connector causes a negative pressure to act on the lumen <NUM> of the sheath main body <NUM>. Accordingly, the sheath <NUM> aspirates the floating thrombi <NUM> from the sheath opening portion <NUM>. The aspirated thrombi <NUM> are discharged to an outside of the living body through the lumen <NUM> and the hub opening portion <NUM>.

When the thrombus <NUM> floating in the blood vessel is larger than the sheath opening portion <NUM>, the thrombus <NUM> does not enter the lumen <NUM> but is caught by the sheath opening portion <NUM>. Accordingly, the sheath opening portion <NUM> is blocked by the large thrombus <NUM>. For solving this blockage, the operator can repeat, by operating the shaft part <NUM>, an operation to lead the cutting part <NUM> into the sheath opening portion <NUM> and an operation to expose the cutting part <NUM> from the sheath opening portion <NUM>. When the cutting part <NUM> moves to the proximal side and is led into the sheath opening portion <NUM>, the large thrombus <NUM> that blocks the sheath opening portion <NUM> is sandwiched between the sheath opening portion <NUM> and the cutting part <NUM>. The cutting part <NUM> having a ring shape receives a part of the thrombus <NUM> having a three-dimensional shape in the inside thereof, and is thus easy to be caught by the thrombus <NUM>. Therefore, as illustrated in <FIG>, the outer edge <NUM> and/or the inner edge <NUM> that each functions as the cutting blade of the cutting part <NUM> can effectively sandwich the thrombus <NUM> that blocks the sheath opening portion <NUM> between the outer edge <NUM> and/or the inner edge <NUM> and the sheath opening portion <NUM>, and cut the thrombus <NUM>. The sandwiched thrombus <NUM> receives a shear force from the sheath opening portion <NUM> and the cutting part <NUM>, and is effectively cut. A site at which the shear force of the cutting part <NUM> is caused to act can be both of or either one of the outer edge <NUM> and the inner edge <NUM> that function as the cutting blade. The thrombi <NUM> having been cut and led into the lumen <NUM> are aspirated by the aspirating device, and are discharged to outside the body.

Meanwhile, the cutting part <NUM> is inclined relative to the center axis X of the shaft part <NUM>. Therefore, the cutting part <NUM> does not come into strong contact with the sheath opening portion <NUM> but can smoothly enter the sheath opening portion <NUM>. Therefore, the cutting part <NUM> is difficult to damage the sheath opening portion <NUM>.

When the cutting part <NUM> moves to the distal side and is exposed from the sheath opening portion <NUM>, the circulation of the lumen <NUM> having been partially blocked by the thrombi <NUM> and the main cutting body <NUM> is increased. This recovers the aspiration force of the sheath opening portion <NUM>. Accordingly, the sheath <NUM> can excellently aspirate the floating thrombus <NUM> from the sheath opening portion <NUM>. The aspirated thrombi <NUM> are discharged to outside the living body through the lumen <NUM> and the hub opening portion <NUM>. Subsequently, when the thrombus <NUM> that is larger than the sheath opening portion <NUM> is aspirated, the thrombus <NUM> does not enter the lumen <NUM> but is caught by the sheath opening portion <NUM>. When the cutting part <NUM> is again led into the sheath opening portion <NUM>, the large thrombus <NUM> that blocks the sheath opening portion <NUM> is cut by being sandwiched between the sheath opening portion <NUM> and the cutting part <NUM>, and removed.

Subsequently, the operator alternately moves the main cutting body <NUM> to the distal side and to the proximal side along the blood vessel. This enables the operator to cut, aspirate, and remove the thrombus <NUM> that is caught by the sheath opening portion <NUM> while causing the thrombus <NUM> adhered on the blood vessel to fall off by the cutting part <NUM>.

After the aspiration and the removal of the thrombi <NUM> has been completed, the operator stops the aspiration by the aspirating device. Thereafter, the operator extracts the removal device <NUM> through the sheath <NUM> to outside the body, and extracts the sheath <NUM>. Accordingly, the procedure of removing the thrombi <NUM> and <NUM> is completed.

As in the foregoing, the removal device <NUM> in the first example includes: the elongated shaft part <NUM>; and the cutting part <NUM> that is fixed to the distal portion of the shaft part <NUM>, and the proximal portion of the cutting part <NUM> includes a ring-shaped cutting blade, and a surface on which the cutting blade is positioned is inclined relative to the center axis of the shaft part <NUM> at an angle of less than <NUM> degrees.

The removal device <NUM> configured as the above is inserted into a body lumen and then pulled to allow the cutting blade to cut an object such as the thrombus <NUM>. The cutting blade having a ring shape receives a part of an object having a three-dimensional shape in an inside of the ring, and is thus easy to be caught by the object. Therefore, the removal device <NUM> can effectively cut and remove the object by the cutting blade that is difficult to slip with respect to the object. Moreover, the surface on which the cutting blade is positioned is inclined relative to the center axis of the shaft part <NUM> at an angle of less than <NUM> degrees, so that the cutting blade is difficult to damage the sheath <NUM> when moving to the proximal side. Accordingly, the removal device <NUM> can suppress damage to another device such as the sheath <NUM>. Note that, the cutting blade can be either one or both of the outer edge <NUM> and the inner edge <NUM>. Accordingly, for example, each of the outer edge and the inner edge does not need to have a ring shape, but a combination of the outer edge and the inner edge may configure the ring shape. Moreover, the surface on which the cutting blade is positioned is inclined relative to the center axis of the shaft part <NUM> at an angle of less than <NUM> degrees, so that in a case where the cutting blade abuts on the distal surface of the sheath <NUM>, the cutting part <NUM> is positioned radially outward of the sheath <NUM>. At this time, the contact with the distal surface of the sheath <NUM> can be further reduced by the surface on which the cutting blade is positioned. Accordingly, the cutting part <NUM> can be smoothly led into the lumen (the lumen <NUM>, which is described later) of the sheath <NUM>.

Moreover, in the cutting part <NUM>, the concave portion <NUM> is formed from the proximal end toward the distal side. Therefore, the cutting part <NUM> has a ring shape, receives a part of the object having a three-dimensional shape in the concave portion <NUM>, and is easy to be caught by the object.

Moreover, the shaft part <NUM> is fixed to a position spaced in the radial direction from the center axis Y of the cutting part <NUM>. Accordingly, a maximum distance from the center axis X of the shaft part <NUM> to the cutting part <NUM> becomes larger than that in a case where the shaft part <NUM> is positioned at the center axis Y of the main cutting body <NUM>. Accordingly, the cutting part <NUM> having a high cut effect can be effectively disposed in the main cutting body <NUM> the size of which is limited in order to be inserted into the body lumen. Note that, the position spaced from the center axis Y of the cutting part <NUM> may be, for example, on the outer peripheral surface of the cutting part <NUM>, but may be on the inner peripheral surface thereof or between the outer peripheral surface and the inner peripheral surface.

Moreover, the shaft part <NUM> is fixed to the proximal end of the cutting blade (the outer edge <NUM> and the inner edge <NUM>). Accordingly, when the cutting part <NUM> that penetrates through the sheath <NUM> and protrudes to the distal side from the sheath <NUM> moves to the proximal side by being pulled by the shaft part <NUM>, the cutting part <NUM> can smoothly enter the sheath opening portion <NUM> because the cutting blade is inclined. Accordingly, the cutting part <NUM> is not caught by the distal end of the sheath <NUM>, thereby improving the operability of the removal device <NUM>.

Moreover, the removal system <NUM> according to the first example includes: the sheath <NUM> in which a lumen to cause a aspiration force to act is formed; and the removal device <NUM> capable of being inserted into the sheath <NUM>, and in the removal system <NUM>, the removal device <NUM> includes the elongated shaft part <NUM>, and the cutting part <NUM> that is fixed to the distal portion of the shaft part <NUM>; the proximal portion of the cutting part <NUM> includes the ring-shaped cutting blade; and a surface on which the cutting blade is positioned is inclined relative to the center axis of the shaft part <NUM> at an angle of less than <NUM> degrees.

The removal system <NUM> configured as the above, by protruding the cutting part <NUM> to the distal side from the sheath <NUM> and then pulling the shaft part <NUM> to the proximal side, can effectively cut an object such as the thrombus <NUM> by being sandwiched between the sheath opening portion <NUM> and the cutting blade. The cutting blade having a ring shape receives a part of an object having a three-dimensional shape in an inside of the ring, and is thus easy to be caught by the object. Therefore, the removal system <NUM> can effectively cut the object by the cutting blade that is difficult to slip with respect to the object. Accordingly, the removal system <NUM> can continuously aspirate and remove the object without clogging the sheath <NUM> with the object. Moreover, the slope <NUM> on which the cutting blade is positioned is inclined relative to the center axis of the shaft part <NUM> at an angle of less than <NUM> degrees, so that the cutting blade is difficult to damage the sheath <NUM> when moving to the proximal side. Accordingly, the removal system <NUM> can suppress damage to another device such as the sheath <NUM>. Note that, the cutting blade can be either one or both of the outer edge <NUM> and the inner edge <NUM>.

Note that, the form of a main cutting body <NUM> is not limited to the abovementioned example. For example, as in a removal device <NUM> serving as a first modification example illustrated in <FIG>, the main cutting body <NUM> may be surrounded by the cutting part <NUM>, and a through-hole <NUM> that penetrates from the distal end to the proximal end may be formed. In other words, the concave portion that is formed in the cutting part <NUM> is formed by being penetrated. This allows the object cut by the cutting part <NUM> to come out from both sides of the through-hole <NUM>, so that the object is difficult to remain in the through-hole <NUM>. Therefore, the removal device <NUM> can maintain the cut effect long. Moreover, even in a case where the through-hole <NUM> is clogged with the object, when the main cutting body <NUM> enters an inside of the sheath <NUM>, the aspiration force acts on the through-hole <NUM>. Therefore, the object having clogged up the through-hole <NUM> is moved to the proximal side, and removed. Therefore, the removal device <NUM> can maintain the cut effect long. Note that, same reference numerals are assigned to parts having the similar functions as those in the aforementioned embodiment, and explanations thereof are omitted.

Moreover, as in a removal device <NUM> serving as a second modification example illustrated in <FIG>, a main cutting body <NUM> may include a tubular body having an approximately central portion in the axial direction the outer diameter of which is large. The shaft part <NUM> may be fixed to an inner peripheral surface of the main cutting body <NUM>, instead of an outer peripheral surface thereof. An outer diameter of a distal portion of the main cutting body <NUM> decreases toward the distal side, and substantially coincides with an inner diameter thereof at the distal end. In other words, the thickness of the distal portion of the main cutting body <NUM> becomes thinner toward the distal side. Therefore, the main cutting body <NUM> can smoothly proceed to the distal side while widening a clearance of a stenosed site of the body lumen.

Moreover, as in a removal device <NUM> serving as a third modification example illustrated in <FIG>, two or more main cutting bodys <NUM> each having a structure similar to that in the abovementioned first modification example may be provided. The plurality of the main cutting bodys <NUM> are arranged so as to surround the shaft part <NUM>. The removal device <NUM> can improve the ability to cut the thrombi <NUM> and <NUM> because the removal device <NUM> is provided with the plurality of the main cutting bodys <NUM>.

Moreover, as in a removal device <NUM> serving as a fourth modification example illustrated in <FIG>, but not falling within the scope of the claimed invention, a main cutting body <NUM> may include a sharp cutting blade <NUM> that protrudes to the proximal side. Accordingly, the cutting blade <NUM> can be formed sharper than a case where the cutting blade <NUM> is formed by obliquely cutting the cylinder. In the fourth modification example, the cutting blade <NUM> is formed on the outer edge <NUM> that is positioned at an outer peripheral surface side of the main cutting body <NUM>. Accordingly, an inner diameter of the cutting part <NUM> spreads in a tapered shape toward the proximal side. This expands a cross-sectional area of the through-hole that is surrounded by the cutting part <NUM>, so that an object serving as a cut target is easy to enter. Accordingly, the cutting part <NUM> can excellently cut the object. Moreover, a slope <NUM> on which the ring-shaped cutting blade <NUM> is positioned does not need to be a plane, but may be a curved surface, for example. An inclined angle θ of the slope <NUM> relative to the center axis X of the shaft part <NUM> may become larger as being apart from the shaft part <NUM> in a direction orthogonal to the center axis X of the shaft part <NUM>. Accordingly, the cutting part <NUM> becomes easy to catch an object, and can excellently cut the object.

Moreover, as in a removal device <NUM> serving as a fifth modification example illustrated in <FIG>, not falling within the scope of the claimed invention, a cutting blade <NUM> of a main cutting body <NUM> may be formed on the inner edge <NUM> that is positioned at an inner peripheral surface side of the main cutting body <NUM>. Accordingly, the outer diameter of the cutting part <NUM> decreases in a tapered shape toward the proximal side. This makes the cutting blade <NUM> difficult to come into contact with the sheath opening portion <NUM>, so that it is possible to suppress damage to the sheath <NUM>. Note that, the cutting blade may be disposed at a position (for example, between the inner peripheral surface and the outer peripheral surface) different from the inner peripheral surface and the outer peripheral surface of the main cutting body.

A removal system <NUM> according to a second embodiment of this invention is different from the first embodiment in that, as illustrated in <FIG>, an expandable part <NUM> capable of expandable in a radial direction (a direction orthogonal to the center axis X of the shaft part <NUM>) is provided at the distal side from a cutting part <NUM>. Note that, same reference numerals are assigned to parts having the similar functions as those in the aforementioned embodiment, and explanations thereof are omitted.

The removal system <NUM> according to the second embodiment is provided with a removal device <NUM> and the sheath <NUM> (see <FIG>). The removal device <NUM> is provided with the expandable part <NUM> and the shaft part <NUM>.

The expandable part <NUM> is a filter that collects an object such as the thrombi <NUM> flowing with the blood. The expandable part <NUM> is provided with a plurality of linear bodies <NUM> that are braided in a net shape so as to configure a tubular body and are flexibly deformable, a distal side interlock portion <NUM>, and a proximal side interlock portion <NUM> (main cutting body) that is interlocked to the shaft part <NUM>. The plurality of the linear bodies <NUM> include gaps <NUM> among the linear bodies <NUM> by being braided.

The distal side interlock portion <NUM> pinches and fixes distal ends of the plurality of the linear bodies <NUM> between the coaxially overlapping two tubular bodies. In the distal side interlock portion <NUM>, a distal side through-hole <NUM> that penetrates from the distal end to the proximal end is formed. The distal side through-hole <NUM> may allow the guide wire to be inserted thereinto. Note that, the distal side through-hole <NUM> does not need to be formed.

The proximal side interlock portion <NUM> pinches and fixes proximal ends of the plurality of the linear bodies <NUM> and the distal end of the shaft part <NUM> between the coaxially overlapping two tubular bodies. In the proximal side interlock portion <NUM>, a proximal side through-hole <NUM> that penetrates from the distal end to the proximal end is formed. The proximal side through-hole <NUM> may allow the guide wire to be inserted thereinto. An end portion of the proximal side interlock portion <NUM> on the proximal side includes a slope <NUM> that is inclined at an angle θ of less than <NUM> degrees relative to the center axis X of the shaft part <NUM>. A ring-shaped site that surrounds the proximal side through-hole <NUM> of the slope <NUM> forms the cutting part <NUM>. Accordingly, the slope <NUM> is a surface on which the cutting blade is positioned.

In a natural state where no external force acts, the expandable part <NUM> becomes in a turned back state where the expandable part <NUM> is turned back in the axial direction by the self elastic force (restoring force) of the linear bodies <NUM>. When the expandable part <NUM> becomes in the turned back state, the proximal side interlock portion <NUM> and the distal side interlock portion <NUM> approach to each other. In turned back state, the expandable part <NUM> is provided with a first site <NUM> that is interlocked to the distal side interlock portion <NUM>, and a second site <NUM> that is interlocked to the proximal side interlock portion <NUM>. The second site <NUM> has entered an interior of the first site <NUM>. In an interior of the expandable part <NUM>, an internal space <NUM> is formed. The second site <NUM> has a concave shape that is open to the proximal side to form a collecting space <NUM> in which the thrombus <NUM> or the like is collected. The first site <NUM> includes a large-diameter portion <NUM> having an approximately constant outer diameter within a prescribed range in the axial direction, in the vicinity of the second site <NUM>. The large-diameter portion <NUM> is a site having an approximately maximum outer diameter of the expandable part <NUM>. A gap 127B in the first site <NUM> is larger than a gap 127A in the second site <NUM>.

The number of the linear bodies <NUM> is not specially limited, and is <NUM> to <NUM>, for example. Moreover, the condition of the braiding of the linear bodies <NUM> is not specially limited. The outer diameter of the linear body <NUM> is selectable as appropriate in accordance with the material of the linear body <NUM> and the usage purpose of the expandable part <NUM>, and is <NUM> to <NUM>, for example.

A constituent material for the linear bodies <NUM> is preferably a material having the flexibility, and for example, a shape memory alloy to which the shape memory effect and the super elasticity are applied by thermal treatment, stainless steel, tantalum (Ta), titanium (Ti), white silver (Pt), gold (Au), tungsten (W), polyolefin such as polyethylene or polypropylene, polyamide, polyester such as polyethylene terephthalate, fluorinated polymer such as tetrafluoroethylene-ethylene copolymer (ETFE), polyether ether ketone (PEEK), polyimide, and the like can be suitably used.

Constituent materials for the distal side interlock portion <NUM> and the proximal side interlock portion <NUM> are not specially limited. For example, stainless steel, polyether ether ketone (PEEK), and the like can be suitably used.

The expandable part <NUM> is elastically deformed by being accommodated in the sheath <NUM> as illustrated in <FIG> to become in a collapsed state in which the outer diameter is small. When the expandable part <NUM> becomes in the collapsed state, the proximal side interlock portion <NUM> and the distal side interlock portion <NUM> are apart from each other.

When the expandable part <NUM> is released from the sheath <NUM>, the expandable part <NUM> is indwelt in the blood vessel in a shape close to the natural state as illustrated in <FIG>. At this time, the large-diameter portion <NUM> comes into contact with the blood vessel wall. The expandable part <NUM> is actually indwelt in the blood vessel wall in a state of being collapsed to more extent in the radial direction than the natural state so as to generate a pressing force with respect to the blood vessel wall by a self expandable force. The large-diameter portion <NUM> comes into contact with the blood vessel wall in a wide area because the large-diameter portion <NUM> has a length to some extent in the axial direction. Therefore, the large-diameter portion <NUM> is firmly fixed to the blood vessel wall.

Note that, the expandable part <NUM> does not need to be in a turned back state immediately after having been released from the sheath main body <NUM> in the blood vessel. In this case, after the expandable part <NUM> has been indwelt in the blood vessel, the sheath main body <NUM> may push the expandable part <NUM> to the distal side. Moreover, a dilator or another sheath is used to push the expandable part <NUM> to the distal side. Accordingly, the second site <NUM> of the expandable part <NUM> has entered an inner side of the first site <NUM>, and becomes in a turned back state.

The expandable part <NUM> that is a filter collects, as illustrated in <FIG>, the thrombi <NUM> having been destroyed by a device that is separately provided in the blood vessel. The thrombi <NUM> are collected in the collecting space <NUM> and the internal space <NUM>. Subsequently, the aspirating device that is connected to the sheath <NUM> causes a negative pressure to act on the lumen <NUM> of the sheath main body <NUM>. Accordingly, the sheath <NUM> aspirates the thrombi <NUM> collected in the collecting space <NUM> from the sheath opening portion <NUM>. The aspirated thrombi <NUM> are discharged to outside the living body through the lumen <NUM>.

In addition, the operator operates the shaft part <NUM> to alternately move the proximal side interlock portion <NUM> to the proximal side and the distal side along the blood vessel. Accordingly, the second site <NUM> of the expandable part <NUM> moves to the distal side and to the proximal side with respect to the first site <NUM>. Therefore, the thrombi <NUM> having been adhered to the expandable part <NUM> by the blood flow are separated from the expandable part <NUM>. Accordingly, the sheath <NUM> can effectively aspirate the thrombi <NUM>.

Moreover, the expandable part <NUM> is in a turned back state, so that the second site <NUM> that is positioned at the inner side is easy to move to the proximal side and the distal side with respect to the first site <NUM> fixed to the blood vessel. This makes it easy to move the proximal side interlock portion <NUM> to the proximal side and the distal side. Moreover, when the range where the first site <NUM> and the second site <NUM> overlap with each other is long in the axial direction, the proximal side interlock portion <NUM> is capable of moving long to the proximal side and the distal side. When the proximal side interlock portion <NUM> moves to the proximal side, the cutting part <NUM> cuts the large thrombus <NUM> that blocks the sheath opening portion <NUM>, and leads the cut thrombi <NUM> into the sheath <NUM>. Accordingly, the sheath <NUM> can excellently continue the aspirating of the thrombi <NUM>.

Moreover, the operator may not only operate the shaft part <NUM> but also may alternately move the sheath <NUM> to the proximal side and the distal side along the blood vessel. The sheath <NUM> moves to the distal side to allow the cutting part <NUM> of the proximal side interlock portion <NUM> to enter the sheath opening portion <NUM> while cutting the thrombus <NUM>.

After the aspirating of the thrombus <NUM> by the sheath <NUM> has been completed, the operator pushes the sheath <NUM> down to the distal side while holding the position of the shaft part <NUM>. Accordingly, the proximal side interlock portion <NUM> is separated from the distal side interlock portion <NUM> while entering an interior of the sheath <NUM>. Further, the expandable part <NUM> becomes in a collapsed state illustrated in <FIG>. Thereafter, the operator extracts the removal device <NUM> together with the sheath <NUM> from the blood vessel, and completes the procedure.

As in the foregoing, the removal device <NUM> in the second embodiment includes the expandable part <NUM> capable of expandable, and the expandable part <NUM> is positioned at the distal side from the cutting part <NUM>. Accordingly, the removal device <NUM> can aspirate and remove the thrombus <NUM> while suppressing the object flowing in the body lumen from flowing downstream by the inflated expandable part <NUM>. The expandable part <NUM> may be directly interlocked to the shaft part <NUM>, or may be interlocked to the shaft part <NUM> via the cutting part <NUM>.

Moreover, the expandable part <NUM> includes the gaps 127A at the proximal side, and the gaps 127B at the distal side larger than the gaps 127A at the proximal side. This allows the small thrombus <NUM> having passed through the gap 127A at the proximal side to be released downstream from the gap 127B at the distal side. Accordingly, the expandable part <NUM> can suppress the thrombi <NUM> from remaining in the internal space <NUM>, and is easy to be collapsed and recovered into the sheath <NUM>.

Moreover, the expandable part <NUM> can be turned back, and the first site <NUM> that is not turned back includes the gaps 127B larger than the gaps 127A of the turned-back second site <NUM>. This allows the small thrombus <NUM> having passed through the gap 127A of the turned-back second site <NUM> to be released downstream from the gap 127B of the first site <NUM> that is not turned back. Accordingly, the expandable part <NUM> can suppress the thrombi <NUM> from remaining in the internal space <NUM>, and is easy to be collapsed and recovered into the sheath <NUM>.

Note that, the form of the expandable part is not limited to the abovementioned example. For example, as in a removal device <NUM> serving as a sixth modification example illustrated in <FIG>, an expandable part <NUM> including the plurality of the linear bodies <NUM> may be provided with at least one release opening portion <NUM> having a gap of the mesh larger than the gaps 127A and the gaps 127B, at the distal side. Therefore, the thrombi <NUM> having passed through the gaps 127A and entered the internal space <NUM> of the expandable part <NUM> can be released from the release opening portion <NUM>, as illustrated in <FIG>. Note that, the thrombi <NUM> having entered the internal space <NUM> are the small thrombi <NUM> having passed through the gaps 127A, so that the thrombi <NUM> flows downstream to hardly affect the living body. The expandable part <NUM> releases the thrombi <NUM> in the internal space <NUM>, and is easy to be collapsed and recovered into the sheath <NUM>.

Moreover, for example, as in a removal device <NUM> serving as a seventh modification example illustrated in <FIG>, an expandable part <NUM> does not need to have a turned back shape in the natural state in which no external force is acted.

Moreover, for example, as in a removal device <NUM> serving as an eighth modification example illustrated in <FIG>, an expandable part <NUM> may be a balloon capable of expandable by a fluid being supplied from a balloon hub <NUM>. The fluid having flowed from the balloon hub <NUM> flows into the expandable part <NUM> through a lumen of a hollow shaft part <NUM>. The expandable part <NUM> closes the blood vessel, and suppresses the thrombi <NUM> from flowing downstream. Accordingly, after the expandable part <NUM> is indwelt in the blood vessel wall, by using the deformation of the expandable part <NUM>, the main cutting body <NUM> including the cutting part <NUM> can be moved in the axial direction.

Note that, this invention is not limited to the above-described embodiments, but various changes by those skilled in the art can be made within the technical scope of this invention. Methods of using the removal device or removal system are not part of the claimed invention. For example, in the abovementioned embodiments, a structure in which the removal system is accessed to a target lesion from the upstream side of the target lesion is employed, however, a structure in which the removal system is accessed to a target lesion from the downstream side thereof may be employed. Moreover, the body lumen into which the removal device is inserted is not limited to the blood vessel, but may be the vessel, the ureter, the bilary duct, the oviduct, or the hepatic duct, for example.

Moreover, in the ring-shaped cutting part, no blade may be formed on a part in the peripheral direction (for example, a site to which the shaft part is fixed). Moreover, the ring-shaped cutting part does not need to be a perfect ring over <NUM> degrees, but a slit that extends in the axial direction may be formed, for example. Moreover, The blade of the cutting part may include saw-like asperities, for example.

Claim 1:
A removal device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), comprising:
an elongated shaft part (<NUM>, <NUM>);
a main cutting body (<NUM>) being an approximately cylindrical member having an outer diameter larger than that of the shaft part (<NUM>, <NUM>); and
a cutting part (<NUM>, <NUM>) that is fixed to a distal portion of the shaft part (<NUM>, <NUM>);
wherein an end portion of the distal side of the main cutting body (<NUM>) includes a distal surface (<NUM>) and an outer peripheral portion (28A) that is positioned radially outward of the distal surface (<NUM>) is subjected to curved surface processing and is smoothly connected to an outer peripheral surface of the main cutting body (<NUM>),
wherein a proximal portion of the cutting part (<NUM>, <NUM>) includes a ring-shaped cutting blade (<NUM>, <NUM>, <NUM>, <NUM>), characterized in that a surface (<NUM>, <NUM>, <NUM>) on which the cutting blade (<NUM>, <NUM>, <NUM>, <NUM>) is positioned is inclined relative to a center axis (X) of the shaft part (<NUM>, <NUM>) at an angle of less than <NUM> degrees, wherein a proximal portion of the main cutting body (<NUM>) is obliquely cut.