Patent Description:
Chronic heart failure is known as a heart disease. Chronic heart failure is broadly classified into systolic and diastolic dysfunctions based on cardiac function indicators. The myocardium of a patient suffering from diastolic dysfunction is enlarged, which results in an increase in Stiffness (hardness), an increase in left atrial blood pressure, and a decline in the pump function of his or her heart. As a result, the patient exhibits a heart failure symptom such as pulmonary edema.

As for some other heart diseases, the blood pressure on the right atrium side increases due to pulmonary hypertension or the like and a decline in the pump function of the heart arises to result in a heart failure symptom.

In recent years, shunt treatment for heart failure patients for forming a shunt (through-hole) in the atrial septum has attracted attention as a treatment method by which heart failure symptoms can be alleviated. The shunt serves as an escape route for an increased atrial pressure.

For example, during the shunt treatment described in PTL <NUM> below, a medical instrument for shunt formation is delivered to the atrial septum by a transvenous approach and a shunt is formed in the atrial septum. Further, during the shunt treatment described above, treatment for denaturing biological tissue around the shunt is performed by means of, for example, an ablation catheter provided with an electrode (maintenance treatment element) so that the shunt is maintained at a desired size for a predetermined period after the shunt formation in the atrial septum.

It may become difficult to maintain the shunt at the desired size and a decline in therapeutic effect may arise when the electrode provided on the catheter is displaced during the ablation for the shunt treatment described above.

The invention has been made to solve the above-described problems and an object of the invention is to provide a medical device capable of preventing a maintenance treatment element imparting energy to biological tissue from being displaced from a treatment target site and to be usable in a treatment method performed on a heart failure patient.

In order to solve this problem, the present invention provides a medical device according to independent claim <NUM>. The dependent claims relate to advantageous embodiments. Methods per sé do not form part of the claimed subject matter.

The device of the present invention can be used for an expansion process of expanding a through-hole formed in an atrial septum so as to allow a right atrium and a left atrium of a heart failure patient to communicate with each other, a confirmation process of confirming hemodynamics in a vicinity of the through-hole, and a process of performing maintenance treatment for maintaining a size of the through-hole.

The medical device is capable of preventing the maintenance treatment element disposed in the concave portion from being displaced from a treatment target site by the concave portion formed when the expansion body is expanded to deform being disposed at the treatment target site (such as the edge portion of the through-hole formed in the atrial septum). As a result, a surgeon such as a doctor using the medical device can perform an appropriate treatment by means of the maintenance treatment element.

The non claimed treatment method includes the confirmation process of confirming the hemodynamics in the vicinity of the through-hole formed in the atrial septum. Accordingly, a surgeon such as a doctor can obtain a determination index during his or her procedure as to whether or not the through-hole formed in the atrial septum is formed in a desired size and can improve the therapeutic effect of heart failure treatment.

Hereinafter, an embodiment of the invention will be described with reference to the accompanying drawings. Note that the following description does not limit the technical scope and the meaning of terms used in the claims. In addition, the dimensional ratios in the drawings are exaggerated for [to be used in an alternative medical device not falling under the scope of the claims. ] <to be used in a medical device falling under the scope of the claims. > convenience of description and may differ from actual ratios.

As illustrated in <FIG>, <FIG>, generally, a medical device <NUM> according to the present embodiment is configured as a device that can be used in a treatment method for alleviating or treating a heart failure symptom by expanding a through-hole Hh formed in an atrial septum HA of a patient's heart H to a predetermined size and maintaining the through-hole Hh at the predetermined size.

<FIG> are diagrams illustrating each portion of the medical device <NUM>. <FIG> is a perspective view illustrating an overall configuration of the medical device <NUM>, <FIG> are perspective views illustrating the distal portion side of the medical device <NUM> in an enlarged manner, and <FIG> are front views illustrating the storage form of an expansion body <NUM>.

In addition, <FIG> are diagrams illustrating a treatment method using the medical device <NUM>. <FIG> is a diagram illustrating a flowchart schematically illustrating each process of the treatment method, <FIG> are diagrams schematically illustrating some of the processes of the treatment method together with the patient's heart H, and <FIG> are cross-sectional views illustrating each process of the treatment method.

In the description of the specification, the side of the medical device <NUM> that is inserted into a living body (side where the expansion body <NUM> is disposed) is referred to as the distal side, the hand operation unit <NUM> side of the medical device <NUM> is referred to as the proximal side, and the direction in which a shaft portion <NUM> stretches is referred to as the axial direction. In addition, the distal portion in the description of the specification means a predetermined range from the distal end (the most distal end) to the proximal side and the proximal portion in the description of the specification means a predetermined range from the proximal end (the most proximal end) to the distal side.

Hereinafter, the medical device <NUM> and the treatment method will be described in detail.

As illustrated in <FIG>, the medical device <NUM> includes the elongated shaft portion <NUM>, the expandable and contractible expansion body <NUM> provided on the distal side of the shaft portion <NUM>, and a maintenance treatment element (energy transmission element) <NUM> disposed in the expansion body <NUM> and imparting energy to biological tissue.

The expansion body <NUM> will be described.

As illustrated in <FIG>, the expansion body <NUM> includes a plurality of expansion portions <NUM>, <NUM>, <NUM>, and <NUM> disposed at different positions in the circumferential direction of the shaft portion <NUM> (R direction in the drawings).

Each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> is configured so as to be expandable and contractible. In the present embodiment, a state where the expansion body <NUM> is expanded means that each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> is in an expanded state and a state where the expansion body <NUM> is contracted means that each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> is in a contracted state. Note that a state at a time when the expansion body <NUM> is expanded is illustrated in <FIG>.

In addition, in the following description of the specification, the expansion portion <NUM> is referred to as the first expansion portion and, similarly, the expansion portion <NUM>, the expansion portion <NUM>, and the expansion portion <NUM> are respectively referred to as the second expansion portion, the third expansion portion, and the fourth expansion portion for convenience. Note that the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> have substantially the same configuration and thus a specific configuration will be described with the first expansion portion <NUM> used as an example and description of the other expansion portions <NUM>, <NUM>, and <NUM> omitted as appropriate.

The first expansion portion <NUM> forms a predetermined concave portion <NUM> in an expanded and deformed state. The concave portion <NUM> has a shape recessed in a concave shape in a direction intersecting with the axial direction of the shaft portion <NUM> (in the up-down direction illustrated in <FIG>). The maintenance treatment element <NUM>, which imparts energy to an edge portion Hhe of the through-hole Hh formed in the atrial septum HA, is disposed in the concave portion <NUM> (see <FIG>).

The concave portion <NUM>, which is formed in the expansion body <NUM> (each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM>), may be formed at least in a state where the expansion body <NUM> is expanded. For example, the concave portion <NUM> may be formed in both a state where the expansion body <NUM> is not expanded and a state where the expansion body <NUM> is expanded. In addition, the size of the concave portion <NUM> (amount by which the concave portion <NUM> is recessed with respect to the axial direction) with respect to the degree of expansion (expansion amount) of the expansion body <NUM> is not particularly limited insofar as the concave portion <NUM> can be disposed with respect to a treatment target site (such as the edge portion Hhe of the through-hole Hh formed in the atrial septum HA) during treatment by means of the maintenance treatment element <NUM>. In addition, the expansion portions provided in the expansion body <NUM> can be appropriately changed in terms of number, shape, and so on.

The concave portion <NUM> is formed in each of the plurality of expansion portions <NUM>, <NUM>, <NUM>, and <NUM> included in the expansion body <NUM>. The maintenance treatment element <NUM> is disposed in the concave portion <NUM> formed in each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM>. Accordingly, in performing treatment with the medical device <NUM>, a surgeon such as a doctor can simultaneously perform the treatment at four locations via the maintenance treatment element <NUM> disposed in each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> (see <FIG>).

As illustrated in <FIG>, a linear member shaped in advance so as to form the concave portion <NUM> when expanded to deform constitutes each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> included in the expansion body <NUM>.

The expansion body <NUM> is configured such that the four expansion portions <NUM>, <NUM>, <NUM>, and <NUM> disposed on the distal side expand and contract as a pulling shaft <NUM> (see <FIG>, described later) is pushed and pulled.

As illustrated in <FIG>, a base portion <NUM> to which each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> is integrally connected is formed on the respective proximal sides of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM>. In addition, a distal portion <NUM> to which each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> is integrally connected is formed on the respective distal sides of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM>.

The linear member that constitutes each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> can be made of, for example, a metal material having a circular cross-sectional shape and a relatively small diameter. In a case where the linear member is made of the metal material, it is possible to use, for example, an alloy having spring properties such as a titanium-based (Ti-Ni, Ti-Pd, Ti-Nb-Sn, or the like) alloy, a copper-based alloy, stainless steel (SUS304), β titanium steel, a Co-Cr alloy, and a nickel-titanium alloy. However, the linear member is not particularly limited in terms of material, cross-sectional shape, outer diameter, and so on and any material, cross-sectional shape, outer diameter, and so can be selected.

In addition, as will be described later, positioning during the treatment by means of the maintenance treatment element <NUM> is performed on each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> by the concave portion <NUM> being fitted (engaged) with respect to the edge portion Hhe of the through-hole Hh formed in the atrial septum HA (see <FIG>). At this time, it is preferable that each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> has a certain degree of hardness such that each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> is not displaced from the edge portion Hhe of the through-hole Hh. From this perspective, it is preferable that each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> has a wire diameter of <NUM> to <NUM> and is formed of a material such as a Ni-Ti alloy in a case where, for example, a wire having a circular cross section is used.

In addition, as for the expansion portions <NUM>, <NUM>, <NUM>, and <NUM>, a dimension L1 of the maximum outer shape during contraction (dimension in the up-down or left-right direction from a central axis C1 of the shaft portion <NUM> illustrated in <FIG>) can be, for example, <NUM> to <NUM> and a dimension L2 of the maximum outer shape during expansion (dimension in the up-down or left-right direction from the central axis C1 of the shaft portion <NUM> illustrated in <FIG>) can be, for example, <NUM> to <NUM>.

An enlarged view of the expansion body <NUM> that is expanded is illustrated in <FIG>.

As illustrated in <FIG>, the first expansion portion <NUM> includes a distal side inclined portion <NUM> inclined obliquely toward the axial center side of the shaft portion <NUM>, a proximal side inclined portion <NUM> inclined obliquely toward the axial center side of the shaft portion <NUM>, and the concave portion <NUM> extending between the distal side inclined portion <NUM> and the proximal side inclined portion <NUM>.

The concave portion <NUM> includes a bottom portion 115a extending along the axial direction (left-right direction in <FIG>), a distal side standing portion 115b formed on the distal side in the axial direction as compared with the bottom portion 115a (to the right of the bottom portion 115a in <FIG>) and rising in a direction intersecting with the axial direction (upward in <FIG>) from the bottom portion 115a, and a proximal side standing portion 115c formed on the proximal side in the axial direction as compared with the bottom portion 115a (to the left of the bottom portion 115a in <FIG>) and rising in a direction intersecting with the axial direction (upward in <FIG>) from the bottom portion 115a. Note that the distal side standing portion 115b and the proximal side standing portion 115c are formed so as to have substantially the same length dimension in the direction of expansion (height direction intersecting with the axial direction) in the expanded state.

The maintenance treatment element <NUM> is disposed in the bottom portion 115a of the concave portion <NUM>. Accordingly, when the concave portion <NUM> is disposed with respect to the edge portion Hhe of the through-hole Hh formed in the atrial septum HA as illustrated in <FIG>, the maintenance treatment element <NUM> disposed in the bottom portion 115a of the concave portion <NUM> comes into contact with the edge portion Hhe of the through-hole Hh. In addition, the first expansion portion <NUM> holds the relative positions of the maintenance treatment element <NUM> and the edge portion Hhe of the through-hole Hh and prevents displacement between the maintenance treatment element <NUM> and the edge portion Hhe of the through-hole Hh by containing a part of the edge portion Hhe of the through-hole Hh in the concave portion <NUM>.

As illustrated in <FIG>, a dimension (width dimension) W1 of the concave portion <NUM> of the first expansion portion <NUM> along the axial direction can be formed larger than, for example, a dimension W2 of the edge portion Hhe of the through-hole Hh along the axial direction. Note that the width dimension W1 of the concave portion <NUM> is the length of a straight line segment interconnecting the part where the distal side standing portion 115b rises most and the part where the proximal side standing portion 115c rises most in the present embodiment. In a case where the concave portion <NUM> has the width dimension described above, the edge portion Hhe of the through-hole Hh can be more reliably contained in the concave portion <NUM>, and thus it is possible to suitably prevent the edge portion Hhe of the through-hole Hh from being displaced from the concave portion <NUM>. The width dimension W1 of the concave portion <NUM> can be, for example, <NUM> to <NUM>.

The maintenance treatment element <NUM> can be formed in, for example, the entire concave portion <NUM> (entire region including the bottom portion 115a, the distal side standing portion 115b, and the proximal side standing portion 115c). In addition, the maintenance treatment element <NUM> can be disposed in, for example, the entire region of the bottom portion 115a that is in contact with the edge portion Hhe of the through-hole Hh (entire region of the bottom portion 115a in the axial direction). By the maintenance treatment element <NUM> being disposed as in each of the disposition examples described above, the maintenance treatment element <NUM> can be more reliably brought into contact with the edge portion Hhe of the through-hole Hh, and thus heat can be suitably imparted to the edge portion Hhe of the through-hole Hh. In addition, the concave portion <NUM> may be formed at least in the expanded state of the expansion body <NUM> and the concave portion <NUM> may not be formed in the expansion body <NUM> that is yet to be expanded (that is in the contracted state).

In addition, in a case where the plurality of expansion portions <NUM>, <NUM>, <NUM>, and <NUM> constitute the expansion body <NUM> as in the present embodiment, the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> may have different positions where the maintenance treatment element <NUM> is disposed and the maintenance treatment element <NUM> may be disposed at the same position or a different position for each expansion portion. Further, the maintenance treatment element <NUM> can be disposed at, for example, any position for each expansion portion also in a case where the maintenance treatment element <NUM> is disposed at a position other than the bottom portion 115a of the concave portion <NUM> as will be described later (see <FIG>).

As illustrated in <FIG> and <FIG>, the expansion body <NUM> includes a circulation portion <NUM> allowing blood flow (indicated by an arrow b in each of the drawings) via the through-hole Hh in a state where the concave portion <NUM> is disposed in the through-hole Hh formed in the atrial septum HA of the patient.

As illustrated in <FIG> and <FIG>, when each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> is expanded, that is, when the expansion body <NUM> is expanded, the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> form gaps (spaces) along the circumferential direction. As illustrated in <FIG> and <FIG>, the expansion body <NUM> that is inserted in the through-hole Hh allows blood to flow from a left atrium HLa to a right atrium HRa via the circulation portion <NUM> that the gaps constitute.

In a case where the expansion body <NUM> is provided with four expansion portions as in the present embodiment, four circulation portions (gaps) <NUM> having substantially the same size are formed between the expansion portions. Note that the circulation portion <NUM> is not particularly limited in terms of shape, size, structure, number, and so on. For example, a hole formed in the expansion body, a notch formed in the expansion body, or the like is capable of constituting the circulation portion <NUM> as will be described later (see <FIG>, <FIG>, and so on).

The expansion body <NUM> (such as each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM>) can be provided with an X-ray contrast marker. The X-ray contrast marker can be formed at, for example, a location indicating the position of the maintenance treatment element <NUM> in the expansion body <NUM>. It is possible to form the X-ray contrast marker by using, for example, a radiopaque material, examples of which include metals such as platinum, gold, silver, titanium, and tungsten and alloys of the metals.

The maintenance treatment element <NUM> disposed in the expansion body <NUM> is capable of including, for example, a heating element (electrode chip) generating heat by receiving high-frequency electric energy from an external energy supply device (not illustrated). The maintenance treatment element <NUM> and the energy supply device are interconnected by a conductive wire (lead wire) coated with an insulating coating material (not illustrated). The conductive wire is electrically connected to the maintenance treatment element <NUM> disposed in each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> with a lumen 105a (described later) inserted. The lumen 105a is formed in the base portion <NUM> of the expansion body <NUM>.

A known high-frequency power source device incorporating a CPU having a function as a control unit or the like is capable of constituting the energy supply device. High-frequency energy supply to the maintenance treatment element <NUM>, stopping of the energy supply, and the like can be controlled via a CPU or the like.

The maintenance treatment element <NUM> can be configured as a monopolar electrode or the like. In this case, a counter electrode plate (not illustrated) or the like is used when treatment is performed by means of the medical device <NUM>. During the treatment by means of the medical device <NUM>, an electric current can be applied to the edge portion Hhe of the through-hole Hh formed in the atrial septum HA by the counter electrode plate being attached to a patient's body surface and a pseudo current circuit being formed between the maintenance treatment element <NUM>, the patient, and the counter electrode plate.

The maintenance treatment element <NUM> may include, for example, a bipolar electrode that allows an electric current to flow between the expansion portions <NUM>, <NUM>, <NUM>, and <NUM>. In addition, although the maintenance treatment element <NUM> of the medical device <NUM> is configured to be capable of performing ablation by means of high-frequency electric energy, an energy transmission element capable of imparting energy to the edge portion Hhe of the through-hole Hh, examples of which include one that performs heating or cooling by means of microwave energy, ultrasound energy, coherent light such as laser, a heated fluid, a cooled fluid, or a chemical medium, one that generates frictional heat, and a heater provided with an electric wire or the like, is capable of constituting the maintenance treatment element <NUM> and specific forms of the maintenance treatment element <NUM> are not particularly limited.

Next, the shaft portion <NUM> will be described.

As illustrated in <FIG>, <FIG>, the shaft portion <NUM> includes a storage sheath <NUM> capable of storing the expansion body <NUM> that is contracted, an outer shaft <NUM> inserted through the storage sheath <NUM>, an inner shaft <NUM> inserted through the outer shaft <NUM>, the pulling shaft <NUM> inserted through the inner shaft <NUM>, and a distal tip <NUM> disposed at the distal end of the shaft portion <NUM>.

The storage sheath <NUM> stores the expansion body <NUM> that is contracted. The storage sheath <NUM> is configured to be capable of moving forward and backward along the axial direction of the shaft portion <NUM>. When the expansion body <NUM> is expanded, the storage sheath <NUM> is moved to the proximal side with respect to the expansion body <NUM>, and then the expansion body <NUM> is exposed (protrudes) from the distal end of the storage sheath <NUM>.

A surgeon such as a doctor grasps the storage sheath <NUM> with his or her fingers or the like and moves the storage sheath <NUM> forward and backward, and then the storage sheath <NUM> can be moved along the axial direction of the shaft portion <NUM>. In addition, a liquid supply section (such as a three-way stopcock) <NUM> for supplying a priming liquid or the like between the storage sheath <NUM> and the outer shaft <NUM>, a tube <NUM> connected to the liquid supply section <NUM>, and the like can be provided as illustrated in <FIG>.

The outer shaft <NUM> is configured such that the distal side of the outer shaft <NUM> is capable of protruding from the storage sheath <NUM> and the proximal side of the outer shaft <NUM> is connected to a hand operation unit <NUM>. As illustrated in <FIG>, the base portion <NUM> of the expansion body <NUM> is inserted through the lumen of the outer shaft <NUM>.

A tubular member stretching in the axial direction constitutes the base portion <NUM> of the expansion body <NUM>. As illustrated in <FIG>, the inner shaft <NUM> is inserted through the base portion <NUM> of the expansion body <NUM>. In addition, the pulling shaft <NUM> is inserted through the lumen of the inner shaft <NUM>.

As illustrated in <FIG>, the inner shaft <NUM> protrudes to the distal side of the outer shaft <NUM>. The pulling shaft <NUM> has a proximal side led out to the proximal side of the hand operation unit <NUM> (see <FIG>) and a distal side led out to the distal side of the inner shaft <NUM>. In addition, the distal end of the pulling shaft <NUM> is connected to the distal portion <NUM> of the expansion body <NUM>. The pulling shaft <NUM> is configured such that the pulling shaft <NUM> can be moved forward and backward along the axial direction by an operation dial <NUM> (described later).

As illustrated in <FIG>, the expansion body <NUM> is configured to be expandable and deformable in a state of being exposed from the storage sheath <NUM> and disposed between the storage sheath <NUM> and the distal tip <NUM>. A surgeon can move the distal portion <NUM> of the expansion body <NUM> connected to the pulling shaft <NUM> to the proximal side by moving the pulling shaft <NUM> to the proximal side. This operation results in a decrease in the distance between the distal portion <NUM> of the expansion body <NUM> and the base portion <NUM> of the expansion body <NUM>. And as illustrated in <FIG>, the expansion body <NUM> expands in a direction intersecting with the axial direction (in the up-down or left-right direction in <FIG>) while contracting in the axial direction.

As illustrated in <FIG>, a guide wire lumen <NUM> extending in the axial direction is formed in the pulling shaft <NUM>, the distal portion <NUM> of the expansion body <NUM> disposed on the distal side of the pulling shaft <NUM>, and the distal tip <NUM> disposed on the distal side of the distal portion <NUM> of the expansion body <NUM>. As illustrated in <FIG>, during treatment by means of the medical device <NUM>, movements of the shaft portion <NUM> and the expansion body <NUM> can be guided by a guide wire <NUM> by the guide wire <NUM> being inserted through the guide wire lumen <NUM>.

As illustrated in <FIG> and <FIG>, the lumen 105a is formed in the base portion <NUM> of the expansion body <NUM>. The conductive wire (not illustrated) connected to the maintenance treatment element <NUM> is inserted through the lumen 105a. The conductive wire can be disposed along, for example, the inside of each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM>. As a result of the disposition described above, it is possible to prevent the conductive wire from hindering a smooth treatment by being disposed on the concave portion <NUM> during treatment by means of the expansion body <NUM>. Note that the conductive wire is, for example, led out from the proximal side of the hand operation unit <NUM> and electrically connected to an energy supply source (not illustrated) as an external device via a predetermined connector or the like similarly to the pulling shaft <NUM>.

As illustrated in <FIG>, the distal tip <NUM> has a tapered shape having an outer shape becoming smaller toward the distal side. An opening portion <NUM> for leading the guide wire <NUM> out to the distal side is formed at the distal end of the distal tip <NUM>. The distal tip <NUM> has a function of preventing a biological tissue injury or the like when the medical device <NUM> is moved into a living body and a function of assisting insertion of the medical device <NUM> through the through-hole Hh formed in the atrial septum HA during the insertion. Note that X-ray contrast properties or the like can be given to the distal tip <NUM>.

In a case where the expansion body <NUM> is provided with the four expansion portions <NUM>, <NUM>, <NUM>, and <NUM> as in the present embodiment, each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> can be stored in, for example, the storage sheath <NUM> as illustrated in <FIG>.

Specifically, each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> can be disposed so as not to overlap the central axis C1 of the shaft portion <NUM> in the up-down direction and the left-right direction when viewed from the front. In other words, the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> are not disposed at circumferentially facing positions with respect to the central axis C1. For example, the first expansion portion <NUM> and the third expansion portion <NUM> facing each other in the up-down direction can be disposed so as to be displaced in the left-right direction in <FIG> with respect to the central axis C1 of the shaft portion <NUM>. In addition, the second expansion portion <NUM> and the fourth expansion portion <NUM> facing each other in the left-right direction can be disposed so as to be displaced in the up-down direction in <FIG> with respect to the central axis C1 of the shaft portion <NUM>. As illustrated in <FIG>, when the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> are disposed in this manner and the expansion body <NUM> is stored in the storage sheath <NUM>, the respective contraction directions of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> do not overlap each other in the up-down and left-right directions when viewed from the front, and thus the shape of the expansion body <NUM> during contraction becomes small. As a result, the expansion body <NUM> can be stored in the storage sheath <NUM> more compactly and the diameter of the storage sheath <NUM> can be reduced.

The storage sheath <NUM>, the outer shaft <NUM>, and the inner shaft <NUM> can be made of, for example, a resin material generally used for a catheter or the like. As an example, polyethylene, polypropylene, an ethylene-propylene copolymer, and the like, a polyolefin such as an ethylene-vinyl acetate copolymer, a thermoplastic resin such as soft polyvinyl chloride, various types of rubber such as silicone rubber and latex rubber, various elastomers such as a polyurethane elastomer, a polyamide elastomer, and a polyester elastomer, and crystalline plastics such as polyimide, crystalline polyethylene, and crystalline polypropylene can be used. In addition, a mesh structure or the like woven from stainless steel or the like can be added as a reinforcement body.

The pulling shaft <NUM> can be made of what is configured by an elongated wire, examples of which include a superelastic alloy such as a nickel-titanium alloy and a copper-zinc alloy, a metal material such as stainless steel, and a resin material having a relatively high rigidity, being coated with a resin material such as polyvinyl chloride, polyethylene, polypropylene, and an ethylene-propylene copolymer.

The distal tip <NUM> can be formed of, for example, a polymer material such as a polyolefin, polyvinyl chloride, a polyamide, a polyamide elastomer, polyurethane, a polyurethane elastomer, polyimide, and fluororesin or a mixture of the polymer materials or a multilayer tube of the two or more polymer materials.

Next, the hand operation unit <NUM> will be described.

As illustrated in <FIG>, the hand operation unit <NUM> includes a housing <NUM>, the operation dial <NUM> disposed in the housing <NUM>, and a conversion mechanism <NUM> converting the rotational operation of the operation dial <NUM> into a forward and backward movement of the pulling shaft <NUM>.

A case that can be grasped with fingers or the like constitutes the housing <NUM>. The conversion mechanism <NUM> illustrated in a simplified manner is disposed in the housing <NUM>. The operation dial <NUM> is disposed with a part of the operation dial <NUM> exposed from the housing <NUM> and can be rotated in the r1-r2 direction in <FIG> by being operated via fingers or the like. The pulling shaft <NUM>, which operates the expansion and contraction of the expansion body <NUM>, is connected to the operation dial <NUM> via the conversion mechanism <NUM>.

When the operation dial <NUM> is rotated in the arrow r1 direction, the medical device <NUM> moves the pulling shaft <NUM> to the proximal side and expands the expansion body <NUM> in conjunction with the movement. In addition, when the operation dial <NUM> is rotated in the arrow r2 direction, the medical device <NUM> moves the pulling shaft <NUM> to the distal side and contracts the expansion body <NUM> in conjunction with the movement. The conversion mechanism <NUM> is capable of including, for example, a rack and pinion mechanism converting the rotation of the operation dial <NUM> into a forward and backward movement (linear movement) of the pulling shaft <NUM>.

Note that the combination between the direction of rotation of the operation dial <NUM> and the direction of movement of the pulling shaft <NUM> can be changed as appropriate. In addition, the hand operation unit <NUM> can be provided with a mechanism moving the pulling shaft <NUM> forward and backward not in conjunction with the rotary operation of the operation dial <NUM> or the like.

As illustrated in <FIG>, the hand operation unit <NUM> can be provided with a tube <NUM> for supplying a priming liquid or the like between the inner shaft <NUM> and the pulling shaft <NUM>. A valve body or the like that prevents the priming liquid supplied via the tube <NUM> from flowing into the proximal side of the housing <NUM> can be appropriately disposed in the housing <NUM>.

A hard resin material, a metal material, or the like is capable of constituting the housing <NUM> of the hand operation unit <NUM>.

Next, a treatment method in which the present embodiment may be employed will be described.

The treatment method includes various treatments performed on a patient suffering from heart failure (left heart failure). More specifically, the treatment method is treatment performed on a patient suffering from chronic heart failure in which the blood pressure of the left atrium HLa increases as the myocardium of a left ventricle HLw of the heart H is enlarged to result in an increase in stiffness (hardness) as illustrated in <FIG>.

Referring to <FIG>, the treatment method includes in summary a process of forming the through-hole Hh in the atrial septum HA (S11), a process of disposing the expansion body <NUM> in the through-hole Hh (S12), a process of expanding the through-hole Hh (S13), a process of confirming the hemodynamics in the vicinity of the through-hole Hh (S14), a process of performing maintenance treatment for maintaining the size of the through-hole Hh (S15), and a process of confirming the hemodynamics in the vicinity of the through-hole Hh after the maintenance treatment (S16). Hereinafter, each process will be described.

In forming the through-hole Hh, a surgeon such as a doctor delivers an introducer <NUM>, in which a guiding sheath 220a and a dilator 220b are combined, to the vicinity of the atrial septum HA as illustrated in <FIG>. The introducer <NUM> can be delivered to the right atrium HRa via, for example, an inferior vena cava Iv. In addition, the introducer <NUM> can be delivered by means of the guide wire <NUM> known in the medical field. The surgeon can deliver the introducer <NUM> along the guide wire <NUM> by inserting the guide wire <NUM> through the dilator 220b.

Note that the insertion of the introducer <NUM> into a living body, the insertion of the guide wire <NUM>, and the like can be performed by a method known in the medical field (method using, for example, an introducer for blood vessel introduction).

Next, the surgeon performs the process (S11) of forming the through-hole Hh in the atrial septum HA.

As illustrated in <FIG>, the through-hole Hh is formed in the atrial septum HA by the surgeon by a predetermined puncture device <NUM> penetrating the atrial septum HA from the right atrium HRa side toward the left atrium HLa side. A device such as a wire having a sharp distal end can be used as the puncture device <NUM>. The puncture device <NUM> is inserted through the dilator 220b illustrated in <FIG> and delivered to the atrial septum HA. The puncture device <NUM> can be delivered to the atrial septum HA instead of the guide wire <NUM> after the guide wire <NUM> is removed from the dilator 220b.

After the through-hole Hh is formed by the puncture device <NUM>, the surgeon widens the through-hole Hh by inserting the dilator 220b through the through-hole Hh. Next, the surgeon removes the puncture device <NUM> from the dilator 220b. After removing the puncture device <NUM>, the surgeon delivers the guide wire <NUM> to the left atrium HLa through the introducer <NUM>. Subsequently, the dilator 220b and the guiding sheath 220a are removed with the guide wire <NUM> left.

The surgeon may perform the process (S11) of forming the through-hole Hh in the atrial septum HA by using the medical device <NUM> instead of the introducer <NUM>. In this case, the storage sheath <NUM> of the medical device <NUM> can be used in place of the guiding sheath 220a and the distal tip <NUM> of the medical device <NUM> can be used in place of the dilator 220b. In a case where the medical device <NUM> is used instead of the introducer <NUM> as described above, it is possible to proceed to the next process without removing the medical device <NUM> after the through-hole Hh is widened by the distal tip <NUM>. In addition, the distal end of the medical device <NUM> can be provided with, for example, a function of puncturing the atrial septum HA. As a result, the atrial septum HA can be punctured by the medical device <NUM> and the through-hole Hh can be widened.

Note that the specific structure of the puncture device <NUM> used for the penetration of the atrial septum HA, the specific procedure for forming the through-hole Hh, and the like are not limited to the content described above.

Next, the surgeon performs the process (S12) of disposing the expansion body <NUM> in the through-hole Hh.

The surgeon delivers the medical device <NUM> along the guide wire <NUM> as illustrated in <FIG>. At this time, the surgeon inserts the distal side of the medical device <NUM> (distal side of the shaft portion <NUM>) through the through-hole Hh. The through-hole Hh is widened by the medical device <NUM> being inserted.

As illustrated in <FIG>, the surgeon exposes the expansion body <NUM> by retracting the storage sheath <NUM> after inserting the medical device <NUM> through the through-hole Hh. The expansion body <NUM> is disposed so as to extend in a direction substantially orthogonal to the opening direction of the through-hole Hh (up-down direction in the drawing). At this time, the concave portion <NUM> of each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> included in the expansion body <NUM> is disposed inside the through-hole Hh.

Next, the surgeon performs the process (S13) of expanding the through-hole Hh.

As illustrated in <FIG>, the surgeon expands the expansion body <NUM> in a state where the expansion body <NUM> is disposed inside the through-hole Hh. The expansion body <NUM> widens the through-hole Hh so as to exceed the diameter of the dilator 220b or the diameter of the storage sheath <NUM> as the expansion body <NUM> is expanded to deform. During the expansion of the expansion body <NUM>, each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> comes into contact with four points of the edge portion Hhe of the through-hole Hh. Accordingly, the through-hole Hh is widened such that the shape of the through-hole Hh forms a substantially polygonal shape (quadrangular shape in the illustrated example) in the plan view illustrated in <FIG>. In the process (S13) of expanding the through-hole Hh, the expansion and contraction of the expansion body <NUM> may be repeated once or a plurality of times in a state where the expansion body <NUM> is disposed inside the through-hole Hh. By the expansion and contraction of the expansion body <NUM> being repeated, the biological tissue of the atrial septum HA around the edge portion Hhe of the through-hole Hh is loosened and becomes likely to be elastically deformed. As a result, the surgeon can more accurately expand the through-hole Hh to a desired size during the treatment using the expansion body <NUM>. As illustrated in <FIG>, the maintenance treatment element <NUM> included in each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> satisfactorily maintains contact with the edge portion Hhe of the through-hole Hh contained inside the concave portion <NUM> (biological tissue in the vicinity of the edge portion Hhe) before and after the expansion of the expansion body <NUM>.

During the expansion of the expansion body <NUM>, the blood flow from the left atrium HLa toward the right atrium HRa is maintained via the circulation portion <NUM> formed in the expansion body <NUM>. As for the patient suffering from the chronic heart failure attributable to the enlargement of the myocardium of the left ventricle HLw, the left atrium HLa becomes higher in blood pressure than the right atrium HRa, and thus the blood that passes through the through-hole Hh flows from the left atrium HLa toward the right atrium HRa.

Next, the surgeon performs the process (S14) of confirming the hemodynamics in the vicinity of the through-hole Hh.

As illustrated in <FIG>, the surgeon delivers a hemodynamic confirmation device <NUM> to the right atrium HRa via, for example, the inferior vena cava Iv. A known echo catheter or the like can be used as the hemodynamic confirmation device <NUM>. The surgeon can cause a display apparatus such as a display to display an echo image acquired by the hemodynamic confirmation device <NUM> and confirm the rate of the blood flow through the through-hole Hh based on the result of the display. Note that the process of confirming the hemodynamics may be started at any of timings before, during, and after the expansion of the through-hole Hh. In addition, the process of confirming the hemodynamics may be ended at any timing following the expansion of the through-hole Hh by the expansion body <NUM>.

By performing the process described above, the surgeon can confirm whether or not the hemodynamics is an assumed one (whether or not the rate of the blood flow from the left atrium HLa to the right atrium HRa is a desired rate). In a case where the surgeon determines based on the result of the hemodynamic confirmation that the blood flow rate is less than the desired rate, the surgeon can increase the amount of expansion of the expansion body <NUM>. This is because the post-maintenance treatment blood flow rate to be described later may become insufficient. In contrast, in a case where the surgeon determines based on the result of the hemodynamic confirmation that the blood flow rate exceeds the desired rate, the surgeon can decrease the amount of expansion of the expansion body <NUM>. This is because the post-maintenance treatment blood flow rate may excessively increase.

In addition, the surgeon can, for example, expand the expansion body <NUM> by a relatively small amount of expansion, confirm the hemodynamics, and then increase the amount of expansion of the expansion body <NUM> in stages. By increasing the size of the through-hole Hh in stages, it is possible to prevent a sudden and significant deformation of the through-hole Hh. As a result, burden on the atrial septum HA can be reduced. Further, it is possible to prevent the biological tissue in the vicinity of the through-hole Hh of the atrial septum HA from undergoing, for example, an injury such as tearing. Note that the process of confirming the hemodynamics can be appropriately performed every time the expansion process is finished.

In addition, the surgeon can, for example, expand the expansion body <NUM> by a relatively large amount of expansion, confirm the hemodynamics, and then decrease the amount of expansion of the expansion body <NUM> in stages. By expanding the through-hole Hh so as to become relatively large in the early stage of the expansion as described above, it is possible to suitably suppress a post-maintenance treatment contraction of the through-hole Hh attributable to an elastic biological tissue deformation.

Next, the surgeon performs the process (S15) of performing the maintenance treatment for maintaining the size of the through-hole Hh.

As illustrated in <FIG> and <FIG>, the surgeon cauterizes the edge portion Hhe of the through-hole Hh with high-frequency energy (heating cauterization) by imparting the high-frequency energy to the edge portion Hhe of the through-hole Hh through the maintenance treatment element <NUM> in a state where the maintenance treatment element <NUM> disposed in the concave portion <NUM> of the expansion body <NUM> is disposed in the vicinity of the edge portion Hhe of the through-hole Hh. During the cauterization through the maintenance treatment element <NUM>, the contact between the maintenance treatment element <NUM> disposed in the concave portion <NUM> and the edge portion Hhe of the through-hole Hh is maintained well. When the biological tissue in the vicinity of the edge portion Hhe of the through-hole Hh is cauterized through the maintenance treatment element <NUM>, a denatured portion Hd in which the biological tissue is denatured is formed in the vicinity of the edge portion Hhe. The biological tissue in the denatured portion Hd loses elasticity, and thus the through-hole Hh is capable of maintaining the shape at a time when the through-hole Hh is widened by the expansion body <NUM>.

When heat is imparted from the maintenance treatment element <NUM> to the edge portion Hhe of the through-hole Hh, each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> comes into contact with the edge portion Hhe and maintains a widened state. Accordingly, the through-hole Hh has a substantially polygonal shape in plan view after the maintenance treatment as illustrated in <FIG>. In addition, the part excluding the part where the denatured portion Hd is formed by the heat being imparted by the maintenance treatment element <NUM> (part extending substantially linearly between the denatured portions Hd in the plan view illustrated in <FIG>) is affected little by the heat imparted from the maintenance treatment element <NUM>, and thus the degree of cauterization (degree of denaturation) is smaller at the part than in the denatured portion Hd. It is possible to prevent thrombus generation around the through-hole Hh by a plurality of locations being locally cauterized without cauterization over the entire circumference of the edge portion Hhe of the through-hole Hh as described above.

Note that the maintenance treatment may be performed while, for example, the expansion body <NUM> is expanded. In addition, the maintenance treatment may be performed while, for example, the expansion body <NUM> is rotated (see the arrows illustrated in <FIG>). At this time, the direction of rotation of the expansion body <NUM> is not particularly limited.

After the cauterization by means of the maintenance treatment element <NUM> is performed, the periphery of the edge portion Hhe of the through-hole Hh is quickly cooled by the blood that passes through the through-hole Hh. Accordingly, it is possible to inhibit the effect of the heat imparted from the maintenance treatment element <NUM> from spreading around the denatured portion Hd.

The maintenance treatment is not limited to the heating by means of the maintenance treatment element <NUM> (heating by means of high-frequency energy). The maintenance treatment can be performed by, for example, a method for performing heating or cooling by means of microwave energy, ultrasound energy, coherent light such as laser, a heated fluid, a cooled fluid, or a chemical medium, a method using a heater provided with an electric wire or the like, a frictional heat generation method, a method using an indwelling tool (described later, see <FIG>), a method based on incision (described later, see <FIG>), or a method in which the methods are combined in any manner.

Next, the surgeon performs the process (S16) of confirming the hemodynamics in the vicinity of the through-hole Hh after the maintenance treatment is performed.

The process of confirming the hemodynamics can be performed by means of the hemodynamic confirmation device <NUM> as described above. The surgeon removes the medical device <NUM> from the through-hole Hh in a case where the rate of the blood flow through the through-hole Hh is the desired rate as a result of the confirmation of the hemodynamics in the vicinity of the through-hole Hh after the maintenance treatment. In removing the medical device <NUM>, the surgeon stores the expansion body <NUM> in the storage sheath <NUM> by contracting the expansion body <NUM>. Subsequently, the medical device <NUM> is removed from the living body along the guide wire <NUM>.

As illustrated in <FIG>, the blood flow through the through-hole Hh is suitably maintained even after the medical device <NUM> is removed from the through-hole Hh. As described above, the blood flow dynamics in the vicinity of the through-hole Hh is confirmed before and after the maintenance treatment with respect to the through-hole Hh, and thus the post-treatment blood flow rate can be adjusted to a desired rate. As a result, the rate of the blood flow from the patient's left atrium HLa toward the patient's right atrium HRa becomes appropriate, heart failure treatment effects can be further improved, and the patient's post-treatment burden can be reduced.

The surgeon can, for example, expand the through-hole Hh again or perform the maintenance treatment with respect to the through-hole Hh again in a case where the blood flow rate is lower than the desired rate as a result of the confirmation of the hemodynamics in the vicinity of the through-hole Hh after the maintenance treatment. By performing these treatments again, it is possible to adjust the size of the through-hole Hh such that the blood flow rate in the through-hole Hh reaches the desired rate. Note that the hemodynamic confirmation, the maintenance treatment, and the expansion of the through-hole Hh can be performed with the expansion body <NUM> disposed in the through-hole Hh during the treatment by means of the medical device <NUM> according to the present embodiment, and thus each of the work processes described above can be, for example, performed at any timing without the medical device <NUM> being replaced. By performing the processes in combination, the surgeon can more accurately adjust the size of the through-hole Hh such that desired hemodynamics can be realized.

For example, in a case where the maintenance treatment is performed again, it is also possible to rotate the expansion body <NUM> and dispose the maintenance treatment element <NUM> in a displaced manner such that the denatured portion Hd is formed at a different site. By performing the treatment in this manner, it is possible to form the denatured portion Hd at a different position in the edge portion Hhe of the through-hole Hh, and thus the post-maintenance treatment shape of the through-hole Hh can be more suitably maintained. In addition, for example, the temperature that is imparted by the maintenance treatment element <NUM> can be changed for each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> or the temperature that is imparted by the maintenance treatment element <NUM> can be changed every time the maintenance treatment is performed.

As described above, the treatment method includes (i) an expansion process of expanding the through-hole Hh formed in the atrial septum HA such that the right atrium HRa and the left atrium HLa of a heart failure patient communicate with each other, (ii) a confirmation process of confirming the hemodynamics in the vicinity of the through-hole Hh, (iii) a process of performing the maintenance treatment for maintaining the size of the through-hole Hh, and (iv) a confirmation process of confirming the hemodynamics in the vicinity of the through-hole Hh after the maintenance treatment.

The medical device <NUM> according to the present embodiment includes the shaft portion <NUM>, the expandable and contractible expansion body <NUM> provided on the distal side of the shaft portion <NUM>, and the maintenance treatment element <NUM> disposed in the expansion body <NUM> and imparting energy to biological tissue. The expansion body <NUM> that is expanded and deformed includes the concave portion <NUM> recessed in a direction intersecting with the axial direction of the shaft portion <NUM>. The maintenance treatment element <NUM> is disposed in the concave portion <NUM>.

The medical device <NUM> is capable of preventing the maintenance treatment element <NUM> disposed in the concave portion <NUM> from being displaced from a treatment target site by the concave portion <NUM> formed when the expansion body <NUM> is expanded to deform being disposed at the treatment target site (such as the edge portion Hhe of the through-hole Hh formed in the atrial septum HA). As a result, a surgeon using the medical device <NUM> can perform an appropriate treatment by means of the maintenance treatment element <NUM>.

In addition, the expansion body <NUM> included in the medical device <NUM> includes the circulation portion <NUM> allowing blood flow via the through-hole Hh in a state where the concave portion <NUM> is disposed in the through-hole Hh formed in the atrial septum HA of a patient.

With the medical device <NUM> described above, a surgeon can dispose the expansion body <NUM> in the through-hole Hh and prevent the blood flow through the through-hole Hh from being suppressed during, for example, the expansion by means of the expansion body <NUM> or the treatment by means of the maintenance treatment element <NUM>. Accordingly, the patient's bodily burden or the like attributable to blocking of the through-hole Hh can be reduced. In addition, the surgeon can confirm the blood flow dynamics in the vicinity of the through-hole Hh in a state where the expansion body <NUM> is disposed in the through-hole Hh, and thus the size of the through-hole Hh can be appropriately adjusted.

In addition, the expansion body <NUM> included in the medical device <NUM> has the concave portions <NUM> at a plurality of different positions in the circumferential direction of the expansion body <NUM> in the expanded and deformed state and the maintenance treatment element <NUM> is disposed in each of the plurality of concave portions <NUM>.

With the medical device <NUM>, the surgeon can simultaneously impart heat to the biological tissue as a treatment target site from the maintenance treatment element <NUM> disposed in each of the plurality of concave portions <NUM> included in the expansion body <NUM>, and thus the surgeon can perform his or her procedure with efficiency. In addition, each of the plurality of concave portions <NUM> included in the expansion body <NUM> is suitably positioned with respect to the treatment target site. Accordingly, treatment can be more reliably performed on a desired site even in a case where heat is simultaneously imparted to a plurality of locations.

In addition, the linear member shaped in advance so as to form the concave portion <NUM> when expanded to deform constitutes the expansion body <NUM> included in the medical device <NUM>.

With the medical device <NUM>, the surgeon can form the concave portion <NUM> in the expansion body <NUM> by expanding and deforming the expansion body <NUM>. Accordingly, the surgeon can smoothly and easily perform the treatment by means of the expansion body <NUM>.

In addition, the concave portion <NUM> of the expansion body <NUM> includes the bottom portion 115a, the distal side standing portion 115b formed on the distal side in the axial direction as compared with the bottom portion 115a and rising in a direction intersecting with the axial direction from the bottom portion 115a, and the proximal side standing portion 115c formed on the proximal side in the axial direction as compared with the bottom portion 115a and rising in a direction intersecting with the axial direction from the bottom portion 115a. And the maintenance treatment element <NUM> is disposed in the bottom portion 115a of the concave portion <NUM>.

With the medical device <NUM>, the maintenance treatment element <NUM> disposed in the bottom portion 115a of the concave portion <NUM> can be more reliably brought into contact with the treatment target site and the surgeon can smoothly perform the procedure by the expansion body <NUM> being disposed such that the concave portion <NUM> contains the treatment target site (such as the edge portion Hhe of the through-hole Hh formed in the atrial septum HA).

In addition, the shaft portion <NUM> of the medical device <NUM> includes the storage sheath <NUM> capable of storing the expansion body <NUM> that is contracted and the distal tip <NUM> disposed on the distal side of the storage sheath <NUM> and having an outer diameter decreasing toward the distal side. And the expansion body <NUM> is configured to be expandable and deformable in a state of being exposed from the storage sheath <NUM> and disposed between the storage sheath <NUM> and the distal tip <NUM>.

With the medical device <NUM>, the surgeon can store the expansion body <NUM> that is contracted in the storage sheath <NUM> until the expansion body <NUM> is delivered to the treatment target site (such as the edge portion Hhe of the through-hole Hh formed in the atrial septum HA), and thus the delivery work can be smoothly performed. And the surgeon can easily position the expansion body <NUM> with respect to the treatment target site by delivering the expansion body <NUM> to the treatment target site and exposing the expansion body <NUM> from the storage sheath <NUM> in a state where the distal tip <NUM> is disposed on the back side (distal side) as compared with the treatment target site. Further, the surgeon can position the maintenance treatment element <NUM> disposed in the concave portion <NUM> of the expansion body <NUM> at the treatment target site by expanding the expansion body <NUM> in a state where the expansion body <NUM> is positioned at the treatment target site.

In addition, the treatment method includes the expansion process of expanding the through-hole Hh formed in the atrial septum HA such that the right atrium HRa and the left atrium HLa of a heart failure patient communicate with each other, the confirmation process of confirming the hemodynamics in the vicinity of the through-hole Hh, and the process of performing the maintenance treatment for maintaining the size of the through-hole Hh.

By the treatment method, a surgeon can obtain a determination index during his or her procedure as to whether or not the through-hole Hh is formed in a desired size by confirming the hemodynamics in the vicinity of the through-hole Hh formed in the atrial septum HA. As a result, the surgeon can improve the therapeutic effect of heart failure treatment.

Next, a treatment method according to a modification example will be described.

As illustrated in <FIG>, the treatment method according to the modification example includes a first expansion process (S23) and a second expansion process (S25) as through-hole expansion processes. The processes other than the processes (S23 and S25) are respectively and substantially the same as the processes described above and thus will not be described. In addition, unless otherwise noted, it is assumed that the processes can be performed in the same procedure as in the above description. Note that a hemodynamic confirmation process (S24) can be omitted as appropriate in the present modification example.

As illustrated in <FIG>, in the first expansion process (preliminary expansion process), a surgeon expands the expansion body <NUM> by a predetermined amount of expansion with the expansion body <NUM> disposed in the through-hole Hh. The surgeon confirms the hemodynamics in the vicinity of the through-hole Hh with the expansion body <NUM> expanded. At this time, the surgeon confirms whether or not the hemodynamics has a desired magnitude. As a result, the surgeon can obtain a determination index as to how much he or she should expand the expansion body <NUM> and the through-hole Hh in the following second expansion process (overexpansion process).

Next, the surgeon performs the second expansion process as illustrated in <FIG>. In the second expansion process, the expansion body <NUM> is expanded such that the amount of expansion becomes larger than when the expansion body <NUM> is expanded in the first expansion process. The standard of the expansion amount of the expansion body <NUM> is adjusted to a size that assumes the amount by which the through-hole Hh contracts due to the elastic deformation of biological tissue after the next process (S26) of performing maintenance treatment. Specifically, in the second expansion process, the amount of contraction at a time when membranous tissue such as the atrial septum is expanded (physically widened) is assumed and the expansion amount (expansion diameter) of the expansion body <NUM> is set such that the size (inner diameter) of the through-hole Hh is substantially the same as the size at the time of the expansion in the first expansion process after the maintenance treatment is finished.

After performing the second expansion process, the surgeon performs the maintenance treatment as illustrated in <FIG>. As in the case described above, the denatured portion Hd is formed in the edge portion Hhe of the through-hole Hh by the maintenance treatment being performed. After performing the maintenance treatment, the expansion body <NUM> is removed from the through-hole Hh as illustrated in <FIG>. When the expansion body <NUM> is removed from the through-hole Hh, the through-hole Hh contracts due to the elastic deformation of the biological tissue. The size of the through-hole Hh becomes substantially the same as the size at the time of the expansion in the first expansion process.

Next, the surgeon confirms the hemodynamics in the vicinity of the through-hole Hh and confirms whether or not the flow rate of the blood that flows from the left atrium HLa to the right atrium HRa is a desired blood flow rate.

As described above, in the treatment method according to the present modification example, the overexpansion process by means of the expansion body <NUM> is performed before the maintenance treatment is performed, and thus it is possible to suppress a decrease in blood flow rate entailed by an elastic biological tissue contraction. Accordingly, hemodynamics substantially the same as the hemodynamics confirmed in the first expansion process is maintained even after the expansion body <NUM> is removed from the through-hole Hh. Accordingly, the flow rate of the blood from the left atrium HLa toward the right atrium HRa of a patient becomes appropriate, heart failure treatment effects can be further improved, and the patient's post-treatment burden can be reduced.

Note that it is possible to perform the maintenance treatment while, for example, overexpanding the expansion body <NUM> in the treatment method according to the modification example. In addition, it is possible to perform the maintenance treatment while, for example, rotating the expansion body <NUM>. In addition, it is possible to overexpand the expansion body <NUM> again after the maintenance treatment and subsequently re-perform the maintenance treatment. At this time, the surgeon may perform the maintenance treatment at a position different from the position where the denatured portion Hd is already formed by rotating the expansion body <NUM> and adjusting the position of the maintenance treatment element <NUM>. In addition, the rotation of the expansion body <NUM>, the overexpansion of the expansion body <NUM>, the maintenance treatment, and the like can be, for example, performed a plurality of times in this order and with this order appropriately changed.

As described above, the treatment method according to the present modification example includes (i) the first expansion process of expanding the through-hole Hh formed in the atrial septum HA such that the right atrium HRa and the left atrium HLa of a heart failure patient communicate with each other, (ii) the second expansion process of expanding the through-hole Hh more than in the first expansion process (increasing the expansion diameter), and (iii) the process of performing the maintenance treatment on the through-hole Hh after the second expansion process.

Next, a medical device according to a modification example, another exemplary treatment method, and so on will be described. Note that treatment using each device, member, and the like described below can be appropriately incorporated into each treatment method described above (<FIG> and <FIG>) and can be appropriately replaced with each corresponding treatment.

A medical device according to Modification Example <NUM> is illustrated in <FIG>.

As illustrated in <FIG>, in the medical device according to the present modification example, the maintenance treatment element <NUM> is disposed in a distal side standing portion 315b included in a concave portion <NUM> of an expansion body <NUM>. Note that the maintenance treatment element <NUM> is also disposed in the distal side standing portion 315b of the concave portion <NUM> of each of expansion portions <NUM>, <NUM>, and <NUM> other than a first expansion portion <NUM> of the expansion body <NUM> although this is illustrated in a simplified manner in <FIG>.

The distal side standing portion 315b is formed so as to have a dimension in the height direction (dimension in the up-down direction in <FIG>) larger than the height-direction dimension of a proximal side standing portion 315c. A bottom portion 315a extends between the distal side standing portion 315b and the proximal side standing portion 315c.

As illustrated in <FIG>, when maintenance treatment is performed with respect to the through-hole Hh, the maintenance treatment element <NUM> is disposed with respect to the edge portion Hhe of the through-hole Hh (edge portion on the distal side in the insertion direction of the expansion body <NUM>). During the disposition, a surgeon can dispose the maintenance treatment element <NUM> in the edge portion Hhe of the through-hole Hh by, for example, moving the expansion body <NUM> to the proximal side (left side in the drawing) after temporarily disposing the maintenance treatment element <NUM> disposed in the concave portion <NUM> on the distal side as compared with the through-hole Hh (right side in the drawing).

It is possible to increase the contact area between the maintenance treatment element <NUM> and the edge portion Hhe of the through-hole Hh by disposing the maintenance treatment element <NUM> in the distal side standing portion 315b of the concave portion <NUM> as illustrated in the present modification example. Accordingly, the post-maintenance treatment size of the through-hole Hh can be suitably maintained.

Note that the maintenance treatment element <NUM> can be disposed in, for example, the proximal side standing portion 315c. In this case, the proximal side standing portion 315c can be formed so as to have, for example, a dimension in the height direction (dimension in the up-down direction in <FIG>) larger than the height-direction dimension of the distal side standing portion 315b. In addition, when the maintenance treatment element <NUM> is disposed in the edge portion Hhe of the through-hole Hh in the case of this configuration, the surgeon can dispose the maintenance treatment element <NUM> in the edge portion Hhe of the through-hole Hh by, for example, moving the expansion body <NUM> to the distal side (right side in the drawing) after temporarily disposing the maintenance treatment element <NUM> disposed in the concave portion <NUM> on the proximal side as compared with the through-hole Hh (left side in the drawing).

Note that the position described in relation to the expansion body <NUM> (see <FIG>) described above, the above-described position of disposition in the distal side standing portion 315b or the proximal side standing portion 315c, and the like can be appropriately combined as to the disposition of the maintenance treatment element <NUM>. For example, in a case where the expansion body is provided with a plurality of expansion portions, it is possible to constitute one expansion body by appropriately combining the disposition forms described above.

In the medical device <NUM> according to the above-described embodiment, each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> is disposed so as not to overlap the central axis C1 of the shaft portion <NUM> in the up-down direction and the left-right direction when viewed from the front (see <FIG>). In contrast, in the present modification example, each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> is disposed such that the expansion portions that face each other overlap in the up-down direction or the left-right direction when viewed from the front. Even in a case where each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> is disposed in this manner, treatment by means of the expansion body <NUM> can be smoothly performed although it is difficult to reduce the size of the storage sheath <NUM>.

A modification example of the maintenance treatment is illustrated in <FIG>.

Although the maintenance treatment is performed by a thermal effect being imparted to the biological tissue by the maintenance treatment element <NUM> disposed in the expansion body <NUM> and the denatured portion Hd (see <FIG>) being formed as a result as described above, specific methods for the maintenance treatment are not limited insofar as the through-hole Hh can be maintained at a desired size. For example, the size of the through-hole Hh can be maintained by means of a predetermined indwelling object or the like as illustrated in the present modification example.

As illustrated in <FIG>, during the maintenance treatment, the size of the through-hole Hh can be maintained by a predetermined member <NUM> being disposed in the edge portion Hhe of the through-hole Hh. A clip-type member made of a biocompatible material, a coil-shaped member, a stent-type member inserted into the entire through-hole Hh, or the like can be used as the member <NUM>.

As illustrated in <FIG>, in another example of the maintenance treatment, the size of the through-hole Hh may be maintained by materials <NUM> such as an adhesive and gel made of a biodegradable material being disposed in the edge portion Hhe of the through-hole Hh. Note that a known biodegradable material can be used as the biodegradable material. In addition, the size of the through-hole Hh may be maintained by, for example, the edge portion Hhe of the through-hole Hh being sutured by means of a suture thread made of a biocompatible or biodegradable material.

Note that the member <NUM> indwelled so that the size of the through-hole Hh is maintained, the various materials <NUM> indwelled in the edge portion Hhe of the through-hole Hh, and the like can be, for example, mounted in the concave portion <NUM> (see <FIG>) of the expansion body <NUM> and delivered to the through-hole Hh.

In addition, as illustrated in <FIG>, the maintenance treatment can be performed by means of, for example, the expansion body <NUM> that is provided with a predetermined cutting unit <NUM>.

The expansion body <NUM> illustrated in <FIG> is provided with the cutting unit <NUM> disposed in the distal side standing portion 115b of the concave portion <NUM>. For example, it is possible to form an incision Hc in the edge portion Hhe of the through-hole Hh as illustrated in <FIG> by moving the expansion body <NUM> to the proximal side (left side in the drawing) from a state where the distal side standing portion 115b is disposed on the distal side of the through-hole Hh (right side in the drawing) as illustrated in <FIG>. The incision Hc formed by the cutting unit <NUM> is likely to cause no elastic biological tissue contraction, and thus the through-hole Hh can be maintained in the shape illustrated in <FIG>.

Note that a cutter having a blade surface formed in a sharp shape, an electric knife, a laser cutter, or the like is capable of constituting the cutting unit <NUM>. In addition, the cutting unit <NUM> can be provided in one expansion body <NUM> in combination with, for example, the maintenance treatment element <NUM> described above. In addition, the cutting unit <NUM> can be disposed in, for example, the proximal side standing portion 115c of the concave portion <NUM>. In the case of such a configuration, it is possible to form the incision Hc in the edge portion Hhe of the through-hole Hh by, for example, moving the expansion body <NUM> to the distal side.

A modification example of the hemodynamic confirmation process is illustrated in <FIG>.

Although an example in which the hemodynamic confirmation in the vicinity of the through-hole Hh is performed by means of the hemodynamic confirmation device <NUM> (such as an echo catheter) disposed in the right atrium HRa has been described above, the hemodynamic confirmation can be performed by means of, for example, pressure measurement catheters <NUM> and <NUM>. Specifically, as illustrated in <FIG>, the pressure measurement catheter <NUM> is delivered to the right atrium HRa via the inferior vena cava Iv and the pressure measurement catheter <NUM> is delivered to the left atrium HLa via the inferior vena cava Iv, the right atrium HRa, and the through-hole Hh. A surgeon acquires the pressure (blood pressure) of the right atrium HRa by using the pressure measurement catheter <NUM>, acquires the pressure (blood pressure) of the left atrium HLa by using the pressure measurement catheter <NUM>, and causes a monitor or the like to display the acquired pressures. The surgeon can confirm the pressure difference between the right atrium HRa and the left atrium HLa based on the display content of the monitor and can grasp the hemodynamics.

A known catheter device can be appropriately used for the pressure measurement catheters <NUM> and <NUM>. In addition, the pressure measurement catheter <NUM> delivered to the left atrium HLa can be delivered via, for example, the guide wire lumen <NUM> of the medical device <NUM> (see <FIG>). Note that it is possible to perform the hemodynamic confirmation by, for example, inserting an echo catheter into the esophagus and acquiring an echo image of the heart H from the esophagus side.

Next, an example of an expansion body that expands the through-hole Hh will be described.

The expansion bodies described below have a function of expanding the through-hole Hh and a function of not suppressing the blood flow through the through-hole Hh in a state of being disposed in the through-hole Hh. Accordingly, by using each of the expansion bodies described below, it is possible to confirm the hemodynamics in the vicinity of the through-hole Hh with the expansion body inserted in the through-hole Hh.

An expansion body <NUM> illustrated in <FIG> includes an expandable skeleton (strut) <NUM> and a circulation portion <NUM> including a gap formed in the skeleton <NUM>. The expansion body <NUM> can be manufactured by, for example, a notch that has a predetermined pattern being formed in a metallic pipe material or the like.

An expansion body <NUM> illustrated in <FIG> includes a main body portion <NUM> including a plurality of wires and a circulation portion <NUM> including a hole portion allowing the inside and the outside of the main body portion <NUM> to communicate with each other.

An expansion body <NUM> illustrated in <FIG> includes a main body portion <NUM> including a plate-shaped member (such as a flat plate-shaped member) and a circulation portion <NUM> including a gap formed in the main body portion <NUM>.

An expansion body <NUM> illustrated in <FIG> includes a main body portion <NUM> including a plate-shaped member and a circulation portion <NUM> including a hole portion formed in the main body portion <NUM>. The distal portion (right side in <FIG>) of the main body portion <NUM> is formed in a tapered shape that tapers toward the distal side.

An expansion body <NUM> illustrated in <FIG> includes a plurality of expansion portions <NUM>, <NUM>, <NUM>, and <NUM> formed of plate-shaped members. The expansion body <NUM> that is contracted is disposed such that each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> is wound in the circumferential direction of the shaft portion <NUM> (state indicated by a broken line in <FIG>). Gaps that form circulation portions <NUM> between the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> are formed when the expansion body <NUM> is expanded.

An expansion body <NUM> illustrated in <FIG> includes a plurality of expansion portions <NUM>, <NUM>, <NUM>, and <NUM> including balloons. The expansion body <NUM> that is contracted is disposed such that each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> is wound in the circumferential direction of the shaft portion <NUM> (state indicated by a broken line in <FIG>). Each of the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> is expanded as illustrated in <FIG> and the through-hole Hh is widened when, for example, a fluid is supplied to the expansion body <NUM> via the shaft portion <NUM> or the like. In addition, gaps that form circulation portions <NUM> between the expansion portions <NUM>, <NUM>, <NUM>, and <NUM> are formed when the expansion body <NUM> is expanded. Note that the specific shape and the like of the expansion portion (balloon) <NUM> are not particularly limited to the illustration.

As described above, the expansion body that is used for the expansion of the through-hole Hh is not particularly limited in terms of shape, material, specific structure, and so on insofar as the expansion body can be inserted into the through-hole Hh and does not hinder the blood flow through the through-hole Hh. For example, the expansion body can be expanded by fluid supply insofar as the balloon structure illustrated in <FIG> is used. In addition, in a case where the expansion body is configured by means of a self-expanding material or the like as another structure, the expansion body can be expanded and contracted by expansion body exposure and protrusion from a sheath or the like. In another example, the expansion body can be configured to be detachable from a shaft portion or the like or can be configured to be indwellable in a through-hole.

Although the medical device according to the invention has been described through the plurality of embodiment and modification examples as described above, the invention is not limited to the content described in the embodiment and can be appropriately changed based on the description of the claims.

For example, the applications of the medical device are not limited to heart failure treatment and the medical device can be applied to various procedures for the purpose of treatment by means of a maintenance treatment element. In addition, omission of an additional member described in the embodiment, addition of an additional member not particularly described, and the like can be appropriately performed.

In addition, one form of the example treatment method may include at least the expansion process of expanding a through-hole formed in the atrial septum, the confirmation process of confirming the hemodynamics in the vicinity of the through-hole, and the process of performing the maintenance treatment in order to maintain the size of the through-hole. In addition, another form of the treatment method may include at least the first expansion process of expanding a through-hole formed in the atrial septum, the second expansion process of expanding the through-hole more than in the first expansion process, and the process of performing the maintenance treatment with respect to the through-hole after the second expansion process.

Claim 1:
A medical device (<NUM>) for maintaining a through-hole (Hh) in an atrial septum (HA) comprising:
a shaft portion (<NUM>);
an expandable and contractible expansion body (<NUM>) disposed distal of the shaft portion (<NUM>); and
a maintenance treatment element (<NUM>) disposed in the expansion body (<NUM>) and performing a predetermined maintenance treatment on biological tissue for maintaining a size of the through-hole (Hh),
wherein the expansion body (<NUM>) includes a concave portion (<NUM>) recessed in a direction intersecting with an axial direction of the shaft portion (<NUM>),
wherein the maintenance treatment element (<NUM>) is an energy transmission element imparting energy to biological tissue, characterised in that
the energy transmission element is disposed in the concave portion (<NUM>) and capable of imparting energy to an edge portion of the through-hole (Hh) formed in the atrial septum (HA) of a patient in a state where the concave portion (<NUM>) is disposed in the through-hole (Hh), and the expansion body (<NUM>) includes a circulation portion (<NUM>) allowing blood flow via the through-hole (Hh) in a state where the concave portion (<NUM>) is disposed in the through-hole (Hh),
wherein a linear member or plate-shape member shaped in advance so as to form the concave portion (<NUM>) when expanded to deform constitutes the expansion body (<NUM>).