Patent Description:
Examples of a treatment method of a stenosed site caused by a plaque, a thrombus, and the like in a blood vessel can include a method of dilating the blood vessel by a balloon and a method of indwelling a mesh-like or coil-like stent in the blood vessel as a support for the blood vessel. However, it is difficult by these methods to treat a stenosed site that is hardened due to calcification, and a stenosed site that occurs in a bifurcated portion of the blood vessel. Examples of a method that allows treatment in such cases include an atherectomy that cuts a stenotic matter such as a plaque or a thrombus.

As a device for the atherectomy, for example, <CIT> describes a catheter that is provided with a mechanism for conveying a cut object. This catheter includes an elongated rotation axis in the interior of a pipe body, and spiral-shaped concave and convex portions are formed on an outer circumference of the rotation axis. The rotation axis is rotatable in the interior of the catheter. When the rotation axis rotates in the catheter, an object located in the spiral-shaped concave portion is conveyed in the axis direction in the interior of the catheter while being pushed by the convex portion.

When an object is conveyed by the catheter described in <CIT>, the object that receives a force from the rotation axis rotates in the interior of the catheter. Accordingly, the object in the interior of the catheter moves to the proximal side while drawing spirals in the interior of the catheter. Therefore, the conveyance distance of the object being conveyed in the interior of the catheter becomes long to decrease the conveyable amount. According to document <CIT>, a second cutting part is formed by a solid spiral carrier. A thrombus is transported via spiral channels between the inner wall of a tube and the spiral carrier.

The invention is made in order to solve the above-described problem, and the object thereof is to provide a medical device that can effectively remove an object in a body lumen. The object of the invention is achieved by a medical device according to claim <NUM>. Advantageous embodiments are carried out according to the dependent claims.

The medical device according to the invention is a medical device for removing an object in a body lumen that includes: a rotatable tubular driving shaft; a cylindrical-shaped first cutting part that is provided on a distal side of the driving shaft, and that rotates together with the driving shaft, and cuts the object; and a second cutting part that is disposed and near the distal side of the driving shaft, inward of the first cutting part.

The treatment method using the medical device is a treatment method of removing an object of a lesion area in a body lumen using the medical device, that includes: a step of inserting the medical device into the body lumen; a step of cutting the object in the body lumen by rotating the first cutting part and second cutting part by the driving shaft, and guiding the cut object to a lumen of the driving shaft; a step of conveying and removing the object to the proximal side, in the lumen of the rotating driving shaft; and a step of extracting the medical device from an interior of the body lumen.

The medical device configured as above can smoothly guide the object cut by the first cutting part and the second cutting part to the lumen of the driving shaft that rotates together with the cutting part. In this process, the cutting part and second cutting part having different characteristics cut the thrombus, so that it is possible to effectively cut and remove the object in the body lumen.

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

A medical device <NUM> according to a first embodiment is inserted into a blood vessel and is used in a treatment of destroying and removing a thrombus, in acute limb ischemia and deep venous thrombosis. In the present description, a side of the device to be inserted into the blood vessel is referred to a "distal side", and a hand-side where the device is operated is referred to as a "proximal side". Note that, an object to be removed is not necessarily limited to a thrombus, a plaque, and a calcified lesion, but all the objects that can exist in a body lumen can be corresponded.

The medical device <NUM> is provided with, as illustrated in <FIG>, an elongated driving shaft <NUM> that is rotationally driven, an outer tube <NUM> that contains the driving shaft <NUM>, a cutting part <NUM> that cuts a thrombus, and a resistive body <NUM> that is disposed in the driving shaft <NUM>. The medical device <NUM> is further provided with an operation unit <NUM> that is provided on a proximal side end portion of the outer tube <NUM>, a rotary drive unit <NUM> that rotates the driving shaft <NUM>, an aspiration pipe body <NUM> that is interlocked with the driving shaft <NUM> in an interior of the operation unit <NUM>, and a syringe <NUM> that is connected to the operation unit <NUM>.

The driving shaft <NUM> is a part for transmitting a rotation force to the cutting part <NUM>, and conveying an object to enter a lumen of the driving shaft <NUM> to the proximal side. The driving shaft <NUM> is provided with, as illustrated in <FIG>, an elongated tubular driving tube <NUM>, a spiral-shaped carrier <NUM> that is provided on an inner peripheral surface of the driving tube <NUM>, and a connection shaft <NUM> that connects the driving tube <NUM> to the rotary drive unit <NUM>.

The driving tube <NUM> penetrates through the outer tube <NUM>, and has a distal portion to which the cutting part <NUM> is fixed. A proximal portion of the driving tube <NUM> is located in an accommodation space <NUM> in the interior of the operation unit <NUM>. The driving tube <NUM> is rotationally driven by the rotary drive unit <NUM> via the connection shaft <NUM>. The driving tube <NUM> includes a leading-out hole <NUM> on a side surface of the proximal portion located in the accommodation space <NUM>. The driving tube <NUM> includes an inlet part <NUM> into which a thrombus enters, in a distal side end portion thereof. In a proximal side end portion of the driving tube <NUM>, the lumen is blocked and the connection shaft <NUM> is fixed. The leading-out hole <NUM> is an outlet from which the thrombus having been entered an interior of the driving tube <NUM> from the inlet part <NUM> is discharged.

The driving tube <NUM> is flexible, and has a characteristic capable of transmitting the power of rotation that is acted from the proximal side to the distal side. The driving tube <NUM> includes, for example, a distal side driving tube 21A in which multiple wires are arranged and interlocked by being wound in a spiral shape, and a proximal side driving tube 21B that is a pipe body interlocked with a proximal side of the distal side driving tube 21A (see <FIG>). The distal side driving tube 21A has a slit (space) between adjacent wires that penetrates from an inner peripheral surface thereof to an outer peripheral surface thereof. The winding direction of the spiral of the wires is preferably a reverse direction of the winding direction of the spiral of the carrier <NUM>, but is not limited thereto. When the winding direction of the spiral of the wires is a reverse direction of the winding direction of the spiral of the carrier <NUM>, the different spirals are reinforced with each other to improve the intensity and to reduce the anisotropy of operations, thereby improving the operability. Note that, the configuration of the driving tube is not specially limited. For example, the driving tube may be a pipe body in which spiral-shaped slits are formed by laser processing or the like.

As for the constituent material for the driving tube <NUM>, for example, stainless steel, Ta, Ti, Pt, Au, W, polyolefin such as polyethylene or polypropylene, polyester such as polyamide or polyethylene terephthalate, fluorinated polymers such as ETFE, PEEK (polyether ether ketone), and polyimide, can be used suitably. Moreover, the constituent material for the driving tube <NUM> may include multiple materials, or a reinforcing member such as a wire may be embedded therein.

The inside diameter of the driving tube <NUM> can be set as appropriate, and is <NUM> to <NUM>, for example. The outside diameter of the driving tube <NUM> can be set as appropriate, and is <NUM> to <NUM>, for example. The length of the driving tube <NUM> in the axis direction can be set as appropriate, and is <NUM> to <NUM>, for example.

The connection shaft <NUM> includes a distal side end portion, which is fixed to the driving tube <NUM>. The connection shaft <NUM> includes an interlock axis 23A on the proximal side that is interlocked with the rotary drive unit <NUM> and receives the power of rotation. A constituent material for the connection shaft <NUM> is not specially limited as long as the rotation power can be transmitted, and is stainless steel, for example. The rotary drive unit <NUM> may be directly connected to the driving tube <NUM>. In that case, the proximal side of the driving tube <NUM> includes a notch, and the notch is interlocked with the rotary drive unit <NUM>. In this process, the lumen on the proximal side of the driving tube <NUM> is sealed with the leading-out hole <NUM>.

The carrier <NUM> is a spiral-shaped part that is provided on the inner peripheral surface of the driving tube <NUM>, and is rotationally driven by the driving tube <NUM>. The carrier <NUM> rotates to cause a force to direct toward the proximal side to act on a thrombus having entered the lumen of the driving tube <NUM>, and to move the thrombus to the proximal side. Moreover, the lumen of the driving tube <NUM> also has a role as a lumen for causing an aspiration force acting from the proximal side to act on the distal side. The carrier <NUM> includes a first carrier <NUM> that is disposed in the interior of the distal portion of the driving tube <NUM>, and a second carrier <NUM> that is disposed closer to the proximal side than the first carrier <NUM> in the interior of the driving tube <NUM>. The first carrier <NUM> has an inter-pitch distance of the spiral longer than that of the second carrier <NUM>. The inter-pitch distance is a movement distance in the axis direction when the spiral is wound at <NUM> degrees in the circumferential direction. The first carrier <NUM> having an inter-pitch distance longer than that of the second carrier <NUM> allows a long distance for conveyance by one rotation, and thus has a large amount of conveyance of the thrombus. Accordingly, the first carrier <NUM> having a long inter-pitch distance is provided in the distal portion of the driving tube <NUM> to allow the lumen on an inlet side (distal side) into which the thrombus enters to be maintained all the time in a state where the lumen is not clogged up with the thrombus. In addition, the first carrier <NUM> having such a long inter-pitch distance receives a large reaction force received from the thrombus being conveyed, and is required to have intensity to some extent. Accordingly, in the present embodiment, the first carrier <NUM> is manufactured by laser processing but is not a coil in which the wires are wound. Note that, the first carrier may be manufactured by winding the wires as long as the first carrier can secure the intensity and is rotatable in the outer tube <NUM>. Alternatively, the carrier <NUM> includes the second carrier <NUM> that is disposed in the interior of the distal portion of the driving tube <NUM>, and the first carrier <NUM> that is disposed closer to the proximal side than the second carrier <NUM> in the interior of the driving tube <NUM>. Accordingly, the second carrier <NUM> having a distance between pitches shorter than that of the first carrier <NUM> is located on the distal side. This makes the distal portion of the driving shaft <NUM> flexible, thereby improving the accessibility of the medical device <NUM> to an object to be cut.

The first carrier <NUM> includes a spiral-shaped spiral part 26A, a distal side ring part 26B that is located on a distal side from the spiral part 26A, and a proximal side ring part 26C that is located on a proximal side from the spiral part 26A. Each of the distal side ring part 26B and the proximal side ring part 26C is a pipe body that is continuous over <NUM> degrees. The first carrier <NUM> is fixed to the inner peripheral surface of the driving tube <NUM> with the distal side ring part 26B and the proximal side ring part 26C. The first carrier <NUM> is fixed with respect to the driving tube <NUM> by welding or bonding, for example. Alternatively, the first carrier <NUM> may be fixed with respect to the driving tube <NUM> by fitting (frictional force). The first carrier <NUM> is partially fixed with respect to the driving tube <NUM>, so that a portion being not fixed (the spiral part 26A in the present embodiment) can be flexibly deformed. This allows the first carrier <NUM> to temporarily deform by a force received from a thrombus being conveyed, so that the breakage can be suppressed. Note that, the fixed position and the number of fixed places of the first carrier <NUM> relative to the driving tube <NUM> are not specially limited. For example, the entire outer peripheral surface of the first carrier <NUM> may be fixed to the driving tube <NUM>. Alternatively, only either one of the distal side and the proximal side of the first carrier <NUM> may be fixed to the driving tube <NUM>. The inside diameters and the outside diameters of the spiral part 26A, the distal side ring part 26B, and the proximal side ring part 26C are respectively correspond to one another. The distal side ring part 26B and the proximal side ring part 26C provide a smooth inner peripheral surface over <NUM> degrees at end portions of the first carrier <NUM>. Accordingly, the distal side ring part 26B and the proximal side ring part 26C come into smooth contact with but do not interfere with the resistive body <NUM> that is located in the interior and relatively rotates, so that the breakage can be suppressed. No distal side ring part 26B may be provided. In this case, the spiral-shaped spiral part 26A further extends in a spiral shape toward the distal side. In this case, the vicinity of a distal side end portion of the spiral-shaped spiral part 26A is joined to the driving tube <NUM> by welding or the like. This can reduce the occupied volume of the first carrier <NUM>, and make a space in the lumen of the driving shaft <NUM> wide. Accordingly, it is possible to more smoothly guide many objects into the lumen of the driving shaft <NUM>, and convey the objects. When the spiral-shaped spiral part 26A configures a distal side end portion of the first carrier <NUM>, the distal side end portion of the spiral part 26A is disposed near a position of a distal side end portion of the cutting part <NUM>. This can continuously guide the objects cut by the cutting part <NUM> to the spiral part 26A. Accordingly, a thrombus T is easily sent to the proximal side in the lumen of the driving shaft <NUM>, and the lumen hardly clogs up.

The second carrier <NUM> is a spiral-shaped member having an inter-pitch distance shorter than that of the first carrier <NUM>. The second carrier <NUM> is a coil, for example. Parts (for example, a distal side end portion and a proximal side end portion) of the second carrier <NUM> are fixed to the inner peripheral surface of the driving tube <NUM>. The second carrier <NUM> is fixed with respect to the driving tube <NUM> by welding or bonding, for example. Alternatively, the second carrier <NUM> may be fixed with respect to the driving tube <NUM> by fitting (frictional force). The second carrier <NUM> is partially fixed with respect to the driving tube <NUM>, so that a portion being not fixed can be flexibly deformed. This allow the second carrier <NUM> to temporarily deform by a force received from a thrombus being conveyed, so that the breakage can be suppressed. Note that, the fixed position and the number of fixed places of the second carrier <NUM> relative to the driving tube <NUM> are not specially limited. For example, the entire outer peripheral surface of the second carrier <NUM> may be fixed to the driving tube <NUM>. Alternatively, only either one of the distal side and the proximal side of the second carrier <NUM> may be fixed to the driving tube <NUM>. The second carrier <NUM> that is a coil is easily manufactured although it is long, so that the cost can be reduced. Moreover, the second carrier <NUM> that is a coil is easily inserted into the interior of the driving tube <NUM> and disposed. The shape of a cross section vertical to the central axis of the second carrier <NUM> is not specially limited, but is a square, a rectangle, a parallelogram, a trapezoid, a circle, or an ellipse, for example.

Constituent materials for the first carrier <NUM> and the second carrier <NUM> preferably have the intensity to some extent so as to allow an object to be conveyed, and for example, a shape memory alloy to which the shape memory effect and the super elasticity are assigned by thermal treatment, stainless steel, Ta, Ti, Pt, Au, W, polyolefin such as polyethylene or polypropylene, polyester such as polyamide or polyethylene terephthalate, fluorinated polymers such as ETFE, PEEK (polyether ether ketone), and polyimide, can be used suitably. As for the shape memory alloy, a Ni-Ti-based, Cu-Al-Ni-based, or Cu-Zn-Al-based alloy, any combination thereof, or the like is preferably used. When the first carrier <NUM> and the second carrier <NUM> are made of a shape memory alloy, the first carrier <NUM> and the second carrier <NUM> can be excellently returned to original shapes after having temporarily deformed by a reaction force received from the thrombus, and thus can maintain the function while suppressing the breakage. The constituent materials for the first carrier <NUM> and the second carrier <NUM> may be different from each other.

An inclined angle α of the spiral relative to the central axis of the first carrier <NUM> can be set as appropriate, and is, for example, <NUM> to <NUM> degrees, preferably <NUM> to <NUM> degrees, and more preferably <NUM> to <NUM> degrees. An inclined angle β (torsion angle) of the spiral relative to the central axis of the second carrier <NUM> is larger than the inclined angle α of the spiral of the first carrier <NUM>, and is, for example, <NUM> to <NUM> degrees, preferably <NUM> to <NUM> degrees, and more preferably <NUM> to <NUM> degrees. The large inclined angle results in the short inter-pitch distance and the short conveyance distance by one rotation, however, can reduce a force necessary for conveyance and suppress the breakage, thereby improving the safety. The small inclined angle results in the long inter-pitch distance and the long conveyance distance by one rotation, however, a force necessary for conveyance becomes large, and enhancing the rigidity and the flexibility is required in order to suppress the breakage.

The inside diameters of the first carrier <NUM> and the second carrier <NUM> can be selected as appropriate, and are <NUM> to <NUM>, for example. The outside diameters of the first carrier <NUM> and the second carrier <NUM> preferably have a prescribed clearance with respect to the inner peripheral surface of the driving tube <NUM> such that the first carrier <NUM> and the second carrier <NUM> can come into contact with an inner wall surface of the driving tube <NUM>, and can be inserted into the driving tube <NUM>. The outside diameters of the first carrier <NUM> and the second carrier <NUM> are <NUM> to <NUM>, for example. The inside diameter of the first carrier <NUM> may be different from the inside diameter of the second carrier <NUM>. Moreover, the outside diameter of the first carrier <NUM> may be different from the outside diameter of the second carrier <NUM>.

The length of the first carrier <NUM> in the axis direction can be selected as appropriate, and is <NUM> to <NUM>, for example. The length of the second carrier <NUM> in the axis direction can be selected as appropriate, and is <NUM> to <NUM>, for example. The carrier <NUM> may include only the first carrier <NUM>. In that case, the length of the first carrier <NUM> in the axis direction may be <NUM> to <NUM>.

The outer tube <NUM> is provided with an outer sheath <NUM> that rotatably contains the driving shaft <NUM>, an extension part <NUM> that is fixed to an outer peripheral surface of a distal portion of the outer sheath <NUM>, a fixing part <NUM> that fixes the extension part <NUM> and the resistive body <NUM>, and a tip tube <NUM> that is fixed to the extension part <NUM>.

The outer sheath <NUM> is a tubular body, and includes a proximal side end portion, which is fixed to the operation unit <NUM>. The distal side end portion of the outer sheath <NUM> is position on a proximal side of the cutting part <NUM>. A cross-sectional area of a gap between the outer sheath <NUM> and the driving tube <NUM> is preferably sufficiently smaller than a cross-sectional area in an interior of the aspiration pipe body <NUM>. This can suppress an aspiration force that acts on the interior of the driving tube <NUM> from the aspiration pipe body <NUM> from diffusing in a space between the outer sheath <NUM> and the driving tube <NUM> through slits between the wires of the driving tube <NUM>.

The extension part <NUM> is fixed to a part of the outer peripheral surface of the distal portion of the outer sheath <NUM>, and extends closer to the distal side than the outer sheath <NUM>. The extension part <NUM> is a member for fixing the resistive body <NUM> and the tip tube <NUM> with respect to the outer sheath <NUM>. The extension part <NUM> is provided only to a part in the circumferential direction of the outer peripheral surface of the outer sheath <NUM> so as not to hinder the cutting part <NUM> from cutting a thrombus. The extension part <NUM> is a plate material, for example, but may be a wire, for example, because the shape thereof is not limited.

The fixing part <NUM> is a member for fixing a part on a distal side of the extension part <NUM> to the resistive body <NUM>. The fixing part <NUM> is located closer to the distal side than the cutting part <NUM> of the extension part <NUM>. The fixing part <NUM> plays a role in bridging a distance between the extension part <NUM> and the resistive body <NUM> that are located away from each other. Accordingly, the fixing part <NUM> has a size that allows the resistive body <NUM> to be disposed to a suitable position with respect to the extension part <NUM>. The fixing part <NUM> is a wire, for example, but the shape thereof is not limited. The fixing part <NUM> may be integrally configured with the extension part <NUM> and the resistive body <NUM>, for example.

The tip tube <NUM> is fixed to the extension part <NUM>. The tip tube <NUM> includes a guide wire lumen <NUM> into which a guide wire can be inserted.

A constituent material for the outer sheath <NUM> is not specially limited, and for example, polyolefin such as polyethylene or polypropylene, polyester such as polyamide or polyethylene terephthalate, or various kinds of elastomers, fluorinated polymers such as ETFE, PEEK (polyether ether ketone), and polyimide, can be used suitably. Moreover, the outer sheath <NUM> may include multiple materials, or a reinforcing member such as a wire may be embedded therein.

The inside diameter of the outer sheath <NUM> can be selected as appropriate, and is, for example, <NUM> to <NUM>, more preferably <NUM> to <NUM>. The outside diameter of the outer sheath <NUM> can be selected as appropriate, and is, for example, <NUM> to <NUM>, more preferably <NUM> to <NUM>.

Constituent materials for the extension part <NUM> and the fixing part <NUM> preferably have the intensity to some extent, and for example, a shape memory alloy to which the shape memory effect and the super elasticity are assigned by thermal treatment, stainless steel, Ta, Ti, Pt, Au, W, polyolefin such as polyethylene or polypropylene, polyester such as polyamide or polyethylene terephthalate, fluorinated polymers such as ETFE, PEEK (polyether ether ketone), and polyimide, can be used suitably. As for the shape memory alloy, a Ni-Ti-based, Cu-Al-Ni-based, or Cu-Zn-Al-based alloy, any combination thereof, or the like is preferably used.

The length in the axis direction of the extension part <NUM> can be selected as appropriate, and is, for example, <NUM> to <NUM>, more preferably <NUM> to <NUM>. The thickness (length along the radial direction of the outer sheath <NUM>) of the extension part <NUM> can be selected as appropriate, and is, for example, <NUM> to <NUM>. The width (length along the circumferential direction of the outer sheath <NUM>) of the extension part <NUM> can be selected as appropriate, and is, for example, <NUM> to <NUM>.

A constituent material for the tip tube <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, or polyimide, or a combination thereof can be used suitably.

The inside diameter of the tip tube <NUM> can be selected as appropriate, and is, for example, <NUM> to <NUM>. The outside diameter of the tip tube <NUM> can be selected as appropriate, and is, for example, <NUM> to <NUM>. The length in the axis direction of the tip tube <NUM> can be selected as appropriate, and is, for example, <NUM> to <NUM>.

The cutting part <NUM> is a part for cutting a thrombus, and is fixed to the outer peripheral surface of the distal portion of the driving tube <NUM>. The cutting part <NUM> is a cylinder that protrudes closer to the distal side than the driving tube <NUM>. The distal side end portion of the cutting part <NUM> is provided with a ring-like sharp blade <NUM> obtained by reducing an outside diameter thereof toward the distal side until the outside diameter coincides with an inside diameter thereof.

A constituent material for the cutting part <NUM> preferably has the intensity to the extent that allows a thrombus to be cut, and for example, stainless steel, Ta, Ti, Pt, Au, W, or a shape memory alloy can be used suitably. As for a constituent material for the cutting part <NUM>, a resin including engineering plastic such as polyether ether ketone (PEEK) may be employed. The cutting part <NUM> may include a surface that is subjected to coating processing.

The inside diameter of the cutting part <NUM> preferably substantially coincides with the outside diameter of the driving tube <NUM> to be contacted, and is, for example, <NUM> to <NUM>. The outside diameter of the cutting part <NUM> preferably substantially coincides with the outside diameter of the outer sheath <NUM>, and is, for example, <NUM> to <NUM>. The length in the axis direction of the cutting part <NUM> can be selected as appropriate, and is, for example, <NUM> to <NUM>.

The resistive body <NUM> is a long part that is disposed in the lumen of the driving shaft <NUM>, and can be rotated relative to the driving shaft <NUM>. The resistive body <NUM> suppresses a thrombus having entered the interior of the driving shaft <NUM> from rotating with the driving shaft <NUM>. The shape of a cross section that is vertical to at least a part of the central axis of the resistive body <NUM> is a non-true circle. The resistive body <NUM> is provided with a first resistive body <NUM> that is located on a distal side of the resistive body <NUM>, and a second resistive body <NUM> that is located on the proximal side of the resistive body <NUM>. The first resistive body <NUM> and the second resistive body <NUM> respectively have cross sections of different shapes that are vertical to the central axis. The shape of the cross section vertical to the central axis of the first resistive body <NUM> is a perfect circle, and the shape of the cross section vertical to the central axis of the second resistive body <NUM> is an approximate rectangle. Such the resistive body <NUM> can be easily manufactured in such a manner that a part of a wire having a cross-sectional shape of a perfect circle remains without any change to obtain the first resistive body <NUM>, and the other parts are crushed by being sandwiched between dies to obtain the flat plate-shaped second resistive body <NUM>. The flat plate means a shape that is relatively long in one direction in two directions where cross-sectional shapes are orthogonal to each other, and has two surfaces generally facing opposite directions. Note that, the first resistive body <NUM> and the second resistive body <NUM> may be manufactured by joining different members. A distal side end portion of the resistive body <NUM> is fixed to the fixing part <NUM> closer to the distal side than the cutting part <NUM>. The first resistive body <NUM> having a cross section of a perfect circular shape that is vertical to the central axis in a distal portion of the resistive body <NUM> is provided, so that an outer surface thereof has a small resistance, and the thrombus is easy to enter the cutting part <NUM> and the interior of the driving shaft <NUM>. An interlock portion between the first resistive body <NUM> and the second resistive body <NUM> is located in an interior of the carrier <NUM>. Accordingly, a thrombus can be guided to the interior of the carrier <NUM> along the first resistive body <NUM> having the outer surface with a small resistance. An end portion on a proximal side of the second resistive body <NUM> is located closer to the proximal side than the carrier <NUM>. This allows the second resistive body <NUM> to suppress a thrombus together with the driving shaft <NUM> from rotating to the end portion on the proximal side of the carrier <NUM>, and to maintain a high conveyance force. The end portion on the proximal side of the carrier <NUM> is located in the interior of the aspiration pipe body <NUM>, but may not be located in the interior of the aspiration pipe body <NUM>. An end portion on the proximal side of the resistive body <NUM> may be located closer to the proximal side than the first carrier <NUM>, and closer to the distal side than the proximal side end portion of the second carrier <NUM>. This can maintain a high conveyance force at a position of the first carrier <NUM> on the distal side where a high conveyance force is required.

The shape of the cross section vertical to the central axis of the second resistive body <NUM> is a non-true circle, so that the second resistive body <NUM> certainly includes a second space with an inner peripheral surface of the driving shaft <NUM> that relatively rotates. Moreover, the first resistive body <NUM> also includes a first space with the inner peripheral surface of the driving shaft <NUM>, and with an inner peripheral surface of the cutting part <NUM>. The space between the resistive body <NUM> and the driving shaft <NUM> and the space between the resistive body <NUM> and the cutting part <NUM> effectively act in order to cause an aspiration force from the proximal side to act. Moreover, the first space and the second space have different shapes. The first space has a cross section that is vertical to the central axis of the medical device <NUM> and has a ring-like shape having a width in the radial direction and an outer circumference and an inner circumference that are respectively concentric circles and perfect circles. The second space has a cross section that is vertical to the central axis of the medical device <NUM> and has a ring-like shape having a width in the radial direction, and an outer circumference that is a circle partially recessed to an inner side in the radial direction and an inner circumference that is a rectangle.

The first resistive body <NUM> has cross sections of the same shape that are vertical to the central axis within the entire range in the axis direction. Accordingly, the first resistive body <NUM> has a surface, which is smooth along the axis direction. This can smoothly slide the thrombus and the like along the first resistive body <NUM>. The second resistive body <NUM> has cross sections of the same shape that are vertical to the central axis within the entire range in the axis direction. Accordingly, the second resistive body <NUM> has a surface, which is smooth along the axis direction. This can smoothly slide the thrombus and the like along the second resistive body <NUM>.

A constituent material for the resistive body <NUM> preferably has the intensity to the extent that can suppress the rotation of a thrombus, and for example, stainless steel, Ta, Ti, Pt, Au, W, or a shape memory alloy such as Nitinol (registered trademark) can be used suitably.

The operation unit <NUM> is a part that is gripped and operated by an operator. The operation unit <NUM> is provided with, as illustrated in <FIG>, a casing <NUM> that includes the accommodation space <NUM> in an interior thereof, a first seal part <NUM> that comes into contact with an outer peripheral surface of the driving shaft <NUM>, and a second seal part <NUM> that comes into contact with an outer peripheral surface of the connection shaft <NUM>.

The casing <NUM> provided with a distal side through-hole <NUM> through which the driving tube <NUM> penetrates, a proximal side through-hole <NUM> through which the connection shaft <NUM> penetrates, and an aspiration hole <NUM> into which the syringe <NUM> can be interlocked. A proximal side opening portion <NUM> of the aspiration pipe body <NUM> is located in the accommodation space <NUM> in the interior of the casing <NUM>. The aspiration pipe body <NUM> is a pipe body for guiding a negative pressure acted from the syringe <NUM> to a prescribed position in the interior of the driving tube <NUM>. A distal side opening portion <NUM> of the aspiration pipe body <NUM> is located on the proximal side of the second carrier <NUM> in the interior of the driving tube <NUM>. Accordingly, the syringe <NUM> is aspirated to allow a negative pressure to be applied to the interior of the driving tube <NUM> via the aspiration pipe body <NUM>.

The rotary drive unit <NUM> is provided with a drive source <NUM>, such as a motor, as illustrated in <FIG>, and is a part for the rotating driving shaft <NUM>. The rotary drive unit <NUM> is provided with a rotatable rotation axis <NUM> to which the connection shaft <NUM> is connected. Note that, the rotary drive unit <NUM> is an external device that can be interlocked with and detached from the operation unit <NUM> in the present embodiment, but may be fixed to the operation unit <NUM>. The rotary drive unit <NUM> is further provided with a switch, a battery, and the like, which are not illustrated.

Next, a usage method of the medical device <NUM> according to the first embodiment will be described using a case where an intravascular thrombus, a calcified lesion, and the like are destroyed and aspirated as an example while referring to a flowchart in <FIG>.

Firstly, the medical device <NUM> in which the rotary drive unit <NUM> is interlocked with the operation unit <NUM>, and the connection shaft <NUM> is interlocked with the rotation axis <NUM>, is prepared (see <FIG>). In the medical device <NUM>, the rotary drive unit <NUM> is operated to make the driving shaft <NUM> be in a rotatable state. Next, a proximal side end portion of a guide wire <NUM> is inserted into the guide wire lumen <NUM> of the medical device <NUM>. Thereafter, the medical device <NUM> is caused to reach a distal side of the thrombus T using the guide wire <NUM> as a guide (Step S10).

Next, the rotary drive unit <NUM> is operated to rotate the driving shaft <NUM> (Step S11). Thereafter, the driving shaft <NUM> is moved to the distal side. As illustrated in <FIG> and <FIG>, this causes the blade <NUM> of the cutting part <NUM> to come into contact with the thrombus T, and the thrombus T to be cut by the rotating blade <NUM> (Step S12). The cut thrombus T enters the interior of the driving tube <NUM> through a lumen of the tubular cutting part <NUM>. In this process, in the interior of the cutting part <NUM>, the first resistive body <NUM> having a cross section of a perfect circular shape that is vertical to the central axis is located. Accordingly, the thrombus T is smoothly guided to the driving tube <NUM> along the outer surface with a small resistance of the first resistive body <NUM>. It is also possible to make the cut thrombus T easy to enter the interior of the driving tube <NUM> through the lumen of the tubular cutting part <NUM> by pushing the medical device <NUM> in.

The thrombus T guided by the driving tube <NUM> comes into contact with the rotating first carrier <NUM>. This causes the thrombus T to receive a force to direct toward a proximal direction and a force to direct toward a rotation direction, from the first carrier <NUM>. In this process, the thrombus T is suppressed from rotating together with the first carrier <NUM> by the second resistive body <NUM> that penetrates through an interior of the first carrier <NUM> and does not rotate. Accordingly, the thrombus T linearly moves with high efficiency along the second resistive body <NUM> to the proximal side, by the force received from the rotating first carrier <NUM> and the reaction force received from the second resistive body <NUM>. This allows the thrombus T to be conveyed to the proximal side by the first carrier <NUM> (Step S13). Moreover, the first carrier <NUM> having an inter-pitch distance longer than that of the second carrier <NUM> has a large amount of conveyance by one rotation. Accordingly, it is possible to maintain the lumens of the cutting part <NUM> and the driving shaft <NUM> on an inlet side into which the thrombus T enters to a state where the thrombus T is not clogged at all times.

When a plunger of the syringe <NUM> interlocked with the aspiration hole <NUM> is pulled, the accommodation space <NUM> of the operation unit <NUM> becomes in a negative pressure, and the interior of the aspiration pipe body <NUM> becomes in a negative pressure via the proximal side opening portion <NUM> of the aspiration pipe body <NUM>. As a generation source of the negative pressure, the syringe <NUM> can be used, but the operation unit <NUM> can be also connected to an aspiration pump and the like.

When the interior of the aspiration pipe body <NUM> becomes in the negative pressure, the interior of the driving tube <NUM> communicated with the aspiration pipe body <NUM> also becomes in the negative pressure. In this process, the aspiration pipe body <NUM> is disposed in an interior of the proximal portion of the driving tube <NUM>. Accordingly, it is possible to suppress the negative pressure from escaping from the slit that is a gap between the wires of the driving tube <NUM>. Note that, in a region on the distal side from the aspiration pipe body <NUM>, the carrier <NUM> can convey the thrombus, so that no aspiration pipe body <NUM> is provided and the slight escape of the negative pressure causes no problem. This can cause the negative pressure to excellently act in the range where the carrier <NUM> of the driving tube <NUM> is provided. When the negative pressure acts on the interior of the driving tube <NUM>, the thrombus T in the interior of the driving tube <NUM> moves to the proximal side. In this manner, the negative pressure is caused to act on the interior of the driving tube <NUM> to allow the thrombus T to be conveyed to the proximal side (Step S14). In this process, the rotating driving shaft <NUM> is located outward of a space serving as a conveyance path. Moreover, the resistive body <NUM> that is located inward of the rotating carrier <NUM> has a cross section of a non-true circular shape that is vertical to the central axis, so that a space is formed between an inner peripheral surface of the carrier <NUM> and the resistive body <NUM>. Accordingly, it is possible to cause an aspiration force in the interior of the driving tube <NUM> that is generated due to the negative pressure to effectively act on the thrombus T. In this manner, the thrombus T linearly moves toward the proximal side and is effectively conveyed, by both of the force by the first carrier <NUM> and the aspiration force. Note that, the aspiration by the syringe <NUM> may not be performed. Moreover, the first carrier <NUM> is partially fixed to the driving tube <NUM> and is deformable, so that the first carrier <NUM> can be deformed even in a case where the thrombus T is large, for example, which suppresses the breakage and obtains high safety. Moreover, the first carrier <NUM> can be returned to an original shape after having been deformed when the first carrier <NUM> includes an elastically deformable material, such as a shape memory alloy, and thus can maintain the performance thereof.

The thrombus T having moved closer to the proximal side than the first carrier <NUM> reaches a position at which the second carrier <NUM> in the interior of the driving tube <NUM> is provided. This causes the thrombus T to receive a force to direct toward the proximal direction and a force to direct toward the rotation direction, from the second carrier <NUM>. In this process, the thrombus T is suppressed from rotating together with the second carrier <NUM> by the second resistive body <NUM> that penetrates through an interior of the second carrier <NUM> and does not rotate. Accordingly, the thrombus T linearly moves with high efficiency along the second resistive body <NUM> to the proximal side, by the force received from the rotating second carrier <NUM> and the reaction force received from the second resistive body <NUM>.

Moreover, the thrombus T having reached a position at which the second carrier <NUM> in the interior of the driving tube <NUM> is provided receives an aspiration force from the aspiration pipe body <NUM>, similar to the case where having reached at the position where the first carrier <NUM> is provided. This causes the thrombus T to linearly move toward the proximal side, and to be effectively conveyed by both of the force by the second carrier <NUM> and the aspiration force. Note that, the aspiration by the syringe <NUM> may not be performed. Moreover, the second carrier <NUM> is partially fixed to the driving tube <NUM> and is deformable, so that the second carrier <NUM> can be deformed even in a case where the thrombus T is large, for example, which suppresses the breakage and obtains high safety. Moreover, the second carrier <NUM> can be returned to an original shape after having been deformed when the first carrier <NUM> includes an elastically deformable material, such as a shape memory alloy, and thus can maintain the performance thereof. Further, the resistive body <NUM> is located closer to the proximal side than the first carrier <NUM> and the second carrier <NUM>, so that the conveyance by the first carrier <NUM> and the second carrier <NUM> is excellently performed.

The thrombus T having reached closer to the proximal side than the second carrier <NUM> is aspirated in the interior of the aspiration pipe body <NUM>, and moves to the proximal side in the interior of the aspiration pipe body <NUM>. Thereafter, the thrombus T in the interior of the aspiration pipe body <NUM> is discharged into an interior of the syringe <NUM> via the accommodation space <NUM>.

Moreover, a cross-sectional area of the gap between the outer sheath <NUM> and the driving tube <NUM> is sufficiently smaller than a cross-sectional area of the interior of the aspiration pipe body <NUM>, so that it is possible to suppress an aspiration force that acts on the interior of the driving tube <NUM> from the aspiration pipe body <NUM> from escaping into a space between the outer sheath <NUM> and the driving tube <NUM>.

Moreover, when the syringe <NUM> causes the negative pressure to be generated in the accommodation space <NUM>, the accommodation space <NUM> is sealed by the first seal part <NUM> and the second seal part <NUM>, so that it is possible to cause the negative pressure to effectively act on the interior of the driving tube <NUM>.

Further, the thrombus T is cut by moving the cutting part <NUM> while being reciprocated in the axis direction, and is continuously conveyed and aspirated, so that it is possible to rapidly remove the thrombus T. In this process, an aspiration force acts on the inlet of the cutting part <NUM>, so that it is possible to aspirate the cut thrombus T without being escaped as much as possible.

After the cutting, the conveyance, and the aspiration of the thrombus T have been completed, the rotation movement of the driving shaft <NUM> is stopped (Step S15). Next, the medical device <NUM> is extracted from the blood vessel, and the treatment is completed (Step S16).

As in the foregoing, the medical device <NUM> according to the first embodiment is the medical device <NUM> for removing the thrombus T (object) in the blood vessel (body lumen), and includes the rotatable tubular driving shaft <NUM> in which the spiral-shaped carrier <NUM> is provided on an inner surface thereof, the cutting part <NUM> that is provided on the distal side of the driving shaft <NUM>, rotates together with the driving shaft <NUM>, and cuts the thrombus T, and the elongated resistive body <NUM> that is disposed in the lumen of the driving shaft <NUM> and can be rotated relative to the driving shaft <NUM>. The medical device <NUM> configured as the above can smoothly guide the thrombus T cut by the rotating cutting part <NUM> to the lumen of the driving shaft <NUM> that rotates together with the cutting part <NUM>. In this process, a force is caused to act on the thrombus T by the carrier <NUM> that is provided to an inner peripheral surface of the driving shaft <NUM> while suppressing the rotation of the thrombus T by the resistive body <NUM>, so that it is possible to move the thrombus T into a desired direction along the resistive body <NUM>. Accordingly, it is possible to cut and effectively remove the intravascular thrombus T.

Moreover, the cutting part <NUM> has a cylindrical shape, and has a sharp edge of an opening portion that is located on the distal side. This linearly pushes down the medical device <NUM> to the distal side to allow the thrombus T to be cut by the first cutting part <NUM>. Accordingly, it is possible to rapidly cut the thrombus T by the first cutting part <NUM>, and convey the thrombus T with high efficiency by the carrier <NUM>.

Moreover, the medical device <NUM> includes the outer sheath <NUM> that rotatably contains the driving shaft <NUM>, and the resistive body <NUM> is directly or indirectly fixed to the outer sheath <NUM>. This can excellently maintain the relative rotation of the driving shaft <NUM> to which the cutting part <NUM> is fixed and the resistive body <NUM>, and can maintain the excellent cutting by the cutting part <NUM>.

Moreover, a treatment method of removing the thrombus T (object) of a lesion area in the blood vessel (body lumen) uses the aforementioned medical device <NUM>. The treatment method includes: a step of inserting the medical device <NUM> into a blood vessel (Step S10); a step of cutting the intravascular thrombus T by rotating the cutting part <NUM> by the driving shaft <NUM>, and guiding the cut thrombus T to the lumen of the driving shaft <NUM> (Step S12); a step of conveying the thrombus T to the proximal side by acting a force on the thrombus T by the carrier <NUM> that is provided in the rotating driving shaft <NUM> while suppressing the rotation of the thrombus T by the resistive body <NUM> (Step S13); and a step of extracting the medical device <NUM> from the interior of the blood vessel (Step S16). The treatment method configured as above can cut the thrombus T by the rotating cutting part <NUM>, and smoothly guide the thrombus T to the lumen of the driving shaft <NUM> that rotates together with the cutting part <NUM>. In this process, a force is caused to act on the thrombus T by the carrier <NUM> that is provided to an inner peripheral surface of the driving shaft <NUM> while suppressing the rotation of the thrombus T by the resistive body <NUM>, so that it is possible to convey the thrombus T into a desired direction along the resistive body <NUM>. Accordingly, it is possible to cut and effectively remove the intravascular thrombus T.

A medical device according to a second embodiment is different from the medical device <NUM> according to the first embodiment only in that a second cutting part <NUM> is provided. Note that, same reference numerals are assigned to parts having the similar functions as those in the first embodiment, and explanations thereof are omitted.

The second cutting part <NUM> is fixed to an outer peripheral surface of the distal side ring part 26B of the first carrier <NUM>, as illustrated in <FIG> and <FIG>. The second cutting part <NUM> includes two spiral-shaped cutting blades <NUM>. The two cutting blades <NUM> have rotationally symmetrical shapes with respect to the central axis of the first carrier <NUM>. Each cutting blade <NUM> includes a concave-like inner surface <NUM> that heads toward the central axis of the first carrier <NUM>, and a convex-like outer surface <NUM> that is an opposite surface of the inner surface <NUM>, and includes a first end face <NUM> and a second end face <NUM> between the inner surface <NUM> and the outer surface <NUM>. The first end face <NUM> is a surface that directs to the proximal side, and is inclined at the same angle as (or different angle from) the spiral of the first carrier <NUM>. The second end face <NUM> is a surface that directs to the distal side, and is inclined with respect to the central axis of the first carrier <NUM> at an angle that is larger than that of the spiral of the first end faces <NUM> and an angle equal to or less than <NUM> degrees. The first end faces <NUM> and the second end face <NUM> intersect on the distal side to constitute a sharp second blade <NUM>. The second cutting part <NUM> is disposed inward of the cutting part <NUM> (first cutting part). The outer surface <NUM> of the second cutting part <NUM> comes into contact with the inner peripheral surface of the cutting part <NUM>. The second blade <NUM> that is located on the most distal side of the second cutting part <NUM> is located closer to the proximal side than the blade <NUM> of the cutting part <NUM>. Accordingly, the second cutting part <NUM> can finely destroy the thrombus T having been cut by the first cutting part, and guide it to the interior of the driving tube <NUM>. Moreover, the second cutting part <NUM> can cut also the thrombus T before being cut by the cutting part <NUM>.

The second blade <NUM> of the second cutting part <NUM> is inclined with respect to the central axis of the first carrier <NUM>, so that the second blade <NUM> can cut into the thrombus T by rotation, and scrape off the thrombus T. Accordingly, the second cutting part <NUM> is different from the cutting part <NUM> that acts so as to cut off the thrombus T by being pushed into the distal side. The cutting part <NUM> cuts off the thrombus T by being pushed down, so that the cutting part <NUM> can cut a large amount of comparatively soft thrombi T. In contrast, the second cutting part <NUM> scrapes the thrombus T off by the rotation force, so that the second cutting part <NUM> can destroy the hard thrombus T. In this manner, the medical device is provided with both of the cutting part <NUM> and the second cutting part <NUM> to allow a variety of the thrombi T to be cut.

The first carrier <NUM> may include no distal side ring part 26B. In this case, the spiral-shaped spiral part 26A further extends to the distal side, and constitutes the distal side end portion of the first carrier <NUM>. In this case, the distal side end portion of the spiral part 26A is disposed so as to follow an inner peripheral surface of the second cutting part <NUM>. This can continuously guide the object cut by the second cutting part <NUM> to the spiral part 26A. Accordingly, the thrombus T is easily sent to the proximal side in the lumen of the driving shaft <NUM>, and the lumen hardly clogs up.

Moreover, the second cutting part <NUM> is provided with the spiral-shaped first end faces <NUM>, so that it is possible to smoothly guide the cut thrombus T to the first carrier <NUM>. When an inclined angle of the first end faces <NUM> is identical with an inclined angle of the spiral of the first carrier <NUM>, it is possible to guide the thrombus T more smoothly to the first carrier <NUM>. Accordingly, the second cutting part <NUM> also functions as a carrier. Note that, the second cutting part <NUM> also functions as a carrier, so that the second cutting part <NUM> has an effect even when having no second blade <NUM> for cutting the thrombus T.

Moreover, the second cutting part <NUM> is located in a gap between an inner peripheral surface of the first carrier <NUM> and an inner peripheral surface of the cutting part <NUM>. Accordingly, as compared with a case where no second cutting part <NUM> is provided, the thrombus T is easy to smoothly enter the interior of the first carrier <NUM>.

As in the foregoing, the medical device according to the second embodiment is the medical device <NUM> for removing the thrombus T (object) in the blood vessel (body lumen), and includes the rotatable tubular driving shaft <NUM>, the cutting part <NUM> that is provided on the distal side of the driving shaft <NUM>, rotates together with the driving shaft <NUM>, and cuts the thrombus T, and the second cutting part <NUM> that is disposed near the distal side of the driving shaft <NUM>, inward of the cutting part <NUM>. The medical device configured as the above can smoothly guide the thrombus T cut by the rotating cutting part <NUM> and the second cutting part <NUM> to the lumen of the driving shaft <NUM> that rotates together with the cutting part <NUM>. In this process, the cutting part <NUM> and the second cutting part <NUM> having different characteristics can cut the thrombus T, so that it is possible to excellently cut and remove the various thrombi T having different characteristics, such as the material, the hardness, the viscosity, and the shape, by one device.

Moreover, the cutting part <NUM> has a sharp edge of an opening portion that is located on the distal side. This linearly pushes down the medical device <NUM> to distal side to allow the thrombus T to be cut by the first cutting part <NUM>. Accordingly, it is possible to rapidly cut the thrombus T by the first cutting part <NUM>, and convey the thrombus T with high efficiency by the carrier <NUM>.

Moreover, the second cutting part <NUM> includes the second blade <NUM> that cuts the thrombus toward the rotation direction by rotation. This causes the second cutting part <NUM> to cut the thrombus T by a rotation force, so that it is possible to generate a higher cutting force, as compared with a case where the thrombus T is cut by the first cutting part <NUM> being pushed down. Accordingly, for example, it is possible to effectively cut even the hard thrombus T by the second cutting part <NUM>.

Moreover, the second blade <NUM> is inclined with respect to the central axis of the second cutting part <NUM>. This allows the second blade <NUM> to cut the thrombus T toward the rotation direction by rotation, and move the cut thrombus T to the proximal side.

Moreover, the second blade <NUM> of the second cutting part <NUM> is located closer to the proximal side than the blade <NUM> of the first cutting part <NUM>. This allows the thrombus T that can be cut by the first cutting part <NUM> being pushed down to be rapidly cut by the first cutting part <NUM>, and the thrombus T that has been cut by the cutting part <NUM> to be cut more finely by the rotating second cutting part <NUM>. Accordingly, it is possible to make the thrombus T easily enter the lumen of the driving shaft <NUM>.

Moreover, a treatment method of removing the thrombus T (object) of a lesion area in the blood vessel (body lumen) using the medical device according to the second embodiment will be described. The treatment method includes: a step of inserting a medical device into a blood vessel; a step of cutting the intravascular thrombus T by rotating the cutting part <NUM> and the second cutting part <NUM> by the driving shaft <NUM>, and guiding the cut thrombus T to the lumen of the driving shaft <NUM>; a step of conveying the thrombus T to the proximal side by the rotating driving shaft <NUM>; and a step of extracting the medical device from the interior of the blood vessel. The treatment method configured as above can cut the thrombus T by the cutting part <NUM> and the second cutting part <NUM> that are rotating, and smoothly guide the thrombus T to the lumen of the driving shaft <NUM> that rotates together with the cutting part <NUM> and the second cutting part <NUM>. In this process, the cutting part <NUM> and the second cutting part <NUM> having different characteristics can cut the thrombus T, so that it is possible to excellently cut and remove the various thrombi T having different characteristics, such as the material, the hardness, the viscosity, and the shape, by one device.

A medical device according to a third embodiment is different from the medical device according to the second embodiment only in the structure of a resistive body <NUM>. Note that, same reference numerals are assigned to parts having the similar functions as those in the first and second embodiments, and explanations thereof are omitted.

In the third embodiment, as illustrated in <FIG>, a first resistive body <NUM> having a perfect circular shape of a cross section vertical to the central axis of the resistive body <NUM> is located closer to the distal side than the second cutting part <NUM>. In other words, a distal side end portion of a second resistive body <NUM> having a cross section of a non-circular shape vertical to the central axis is located closer to the proximal side than the blade <NUM> of the first cutting part <NUM> and closer to the distal side than the second blade <NUM> of the second cutting part <NUM>. Accordingly, the second resistive body <NUM> that suppresses the rotation of the thrombus T is located in the interior of the second cutting part <NUM>. The second cutting part <NUM> cuts the thrombus T by the rotation force, so that the second cutting part <NUM> can excellently cut the thrombus T by the rotation of the thrombus T in the interior of the second cutting part <NUM> being suppressed. Moreover, the second cutting part <NUM> is also a carrier that is provided with the spiral-shaped first end faces <NUM>, so that the second cutting part <NUM> can smoothly guide the thrombus T to the lumen of the driving tube <NUM> by the rotation of the thrombus T in the interior thereof being suppressed by the second resistive body <NUM>.

A medical device according to a fourth embodiment is different from the medical device according to the third embodiment only in the length in the axis direction of a second cutting part <NUM>. Note that, same reference numerals are assigned to parts having the similar functions as those in the first to third embodiments, and explanations thereof are omitted.

In the fourth embodiment, as illustrated in <FIG>, the second blade <NUM> that is located on the most distal side of the second cutting part <NUM> is located closer to the distal side than the blade <NUM> of the cutting part <NUM>. Accordingly, the second cutting part <NUM> can effectively cut the thrombus T before the cutting part <NUM> is used to cut the thrombus T. Accordingly, it is possible to effectively cut the hard thrombus T by the second cutting part <NUM> and to guide it into the interior of the driving tube <NUM>. Therefore, the medical device according to the fourth embodiment is effective in cutting multiple hard thrombi T. Note that, the position of the second blade <NUM> of the second cutting part <NUM> may be the same in the axis direction as the position of the blade <NUM> of the cutting part <NUM>. In this case, the medical device can cause both of the first cutting part <NUM> and the second cutting part <NUM> to simultaneously act on the thrombus T to allow a variety of the thrombi T to be cut with a good balance.

In the fourth embodiment, the second blade <NUM> of the second cutting part <NUM> is located closer to the distal side than the blade <NUM> of the cutting part <NUM> (first cutting part). Accordingly, it is possible to cut the thrombus T by the rotating second cutting part <NUM> before the cutting part <NUM> is used for cutting. Accordingly, it is possible to effectively cut, by the second cutting part <NUM>, the thrombus T that is difficult to be cut only by the cutting part <NUM> being pushed down. Accordingly, it is possible to cut with a good balance a variety of the thrombi T including a hard thrombus, for example.

A medical device according to a fifth embodiment is different from the medical device according to the fourth embodiment only in the shape of a second cutting part <NUM>. Note that, same reference numerals are assigned to parts having the similar functions as those in the first to fourth embodiments, and explanations thereof are omitted.

In the fifth embodiment, as illustrated in <FIG>, an inside diameter of the second cutting part <NUM> becomes large in a tapered shape toward a blade on the distal side. In other words, the second blade <NUM> of the second cutting part <NUM> becomes thinner toward the distal side. Accordingly, a cutting force received by the thrombus T that enters the interior of the second cutting part <NUM> gradually becomes larger toward the distal side with respect to the second cutting part <NUM>. Accordingly, it is possible to smoothly guide the thrombus T to the interiors of the second cutting part <NUM> and the cutting part <NUM> with low resistance.

A medical device according to a sixth embodiment is different from the medical device according to the second embodiment only in the structure of a first cutting part <NUM>. Note that, same reference numerals are assigned to parts having the similar functions as those in the first and second embodiments, and explanations thereof are omitted.

In the sixth embodiment, as illustrated in <FIG>, a distal side end portion of the tubular first cutting part <NUM> is formed in a saw-tooth shape by convex portions <NUM> and concave portions <NUM> being arranged in the circumferential direction. The convex portion <NUM> is provided with sharp blades <NUM> in an end portion that is tapered toward the distal side. Moreover, the convex portion <NUM> is provided with grinding particles <NUM> on a surface thereof. Note that, no grinding particles may be provided. The second cutting part <NUM> is disposed in an interior of the first cutting part <NUM>. The blade <NUM> is located closer to the distal side than the second blade <NUM> of the second cutting part <NUM>, but the position is not limited thereto.

In the treatment using the medical device according to the sixth embodiment, when a stenosed site such as the thrombus T is formed of comparatively hard tissues, it is possible to efficiently cut the stenosed site due to the rotation of the first cutting part <NUM>, by the blades <NUM> and the grinding particles <NUM> of the first cutting part <NUM>. In contrast, when the stenosed site is formed of the comparatively soft tissues, it is possible to effectively cut the stenosed site by pushing down the first cutting part <NUM> into the stenosed site due to the movement of the first cutting part <NUM> in the axis direction. In addition, when this medical device is used in treatment for a mixed lesion in which the stenosed site includes both of a hard tissue and a soft tissue, this medical device can simultaneously conduct cutting by the blades <NUM> and the grinding particles <NUM>, and cutting with the movement of the first cutting part <NUM> in the axis direction. Accordingly, this medical device can effectively cut the stenosed site. The mixed lesion that has been cut by the first cutting part <NUM> is further finely cut by the rotating second cutting part <NUM>, and is effectively conveyed to the proximal side by the second cutting part <NUM>. The second cutting part <NUM> is disposed in the interior of the first cutting part <NUM>. The number of blades in the first cutting part <NUM> is more than the number of blades in the second cutting part <NUM>. This makes it easy to secure the lumen of the driving shaft <NUM>, thereby allowing easy aspiration.

When the hard tissue is cut by the first cutting part <NUM>, a powdered cutting fragment may be generated in some cases. In this process, the second cutting part <NUM> is rotated to generate a flow in the proximal direction to make it easy to aspirate the powdered cutting fragments in the proximal direction.

A convex portion <NUM> according to a modification example may include, as illustrated in <FIG>, a smooth outer surface part <NUM> formed outward of a distal end blade <NUM> of the convex portion <NUM>. Grinding particles <NUM> are provided in the vicinity of the blade <NUM> on a distal end of the convex portion <NUM>. Note that, no grinding particles <NUM> may be provided. The outer surface part <NUM> is located radially outward of the first cutting part <NUM> from the blade <NUM>. The outer surface part <NUM> is subjected to R processing, for example, and is formed as a curved surface that is curved in a convex shape. Accordingly, even when the blade <NUM> comes into contact with a blood vessel wall, a vascular wall, or a guiding sheath, the outer surface part <NUM> can smoothly slide on the blood vessel wall, the vascular wall, or the guiding sheath. Accordingly, it is possible to preferably suppress the blood vessel wall, the vascular wall, or the guiding sheath from being damaged.

Note that, the invention is not limited to the above-described embodiment, but various changes by those skilled in the art can be made within the technical scope of the present invention. For example, the body lumen into which the medical 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. Accordingly, the object to be destroyed may be an object other than the thrombus.

Moreover, the resistive body may not include a part having a cross section of a perfect circular shape vertical to the central axis. For example, as in a modification example illustrated in <FIG>, both of a first resistive body <NUM> and a second resistive body <NUM> in a resistive body <NUM> respectively have cross sections of rectangular shapes vertical to the central axis, and elongated axes of the respective cross sections may be orthogonal to each other.

Moreover, as in another modification example illustrated in <FIG>, a resistive body <NUM> may be twisted. The rotation direction of the torsion may be the same as or different from the rotation direction of the spiral of the carrier. The inter-pitch distance of the torsion is preferably longer than the inter-pitch distance of the carrier. This allows the thrombus T that receives the rotation force from the carrier to be conveyed in the axis direction while the thrombus T is released to some extent in the rotation direction along the resistive body <NUM>. Accordingly, it is possible to transmit the force to the thrombus T with high efficiency, and covey the thrombus T with an optimal route.

Moreover, although the carrier <NUM> in the above-described embodiments includes both of the first carrier <NUM> and the second carrier <NUM>, the carrier <NUM> may include either one. Moreover, the carrier may further include one or more other carriers different from the first carrier <NUM> and the second carrier <NUM>.

Claim 1:
A medical device (<NUM>) for removing an object (T) in a body lumen, the medical device (<NUM>) comprising:
a rotatable tubular driving shaft (<NUM>);
a cylindrical-shaped first cutting part (<NUM>, <NUM>) that is provided on a distal side of the driving shaft (<NUM>), and that rotates together with the driving shaft (<NUM>), and cuts the object (T); and
a second cutting part (<NUM>) that is disposed near the distal side of the driving shaft (<NUM>), inward of the first cutting part (<NUM>, <NUM>), wherein
a distal end of the second cutting part (<NUM>) is located proximal to a distal end of the first cutting part (<NUM>, <NUM>),
characterized in that
the second cutting part (<NUM>) is fixed to a spiral shaped carrier (<NUM>) contacting an inner surface of the rotatable tubular driving shaft (<NUM>), and
a lumen of the second cutting part (<NUM>) extends through the spiral shaped carrier (<NUM>).