Introducer sheath and method for using the same

A primary lumen and a secondary lumen, which is formed so as to be expandable, are formed inside a sheath main body having a deformation portion which is disposed so as to include at least a part of the outer peripheral portion of the sheath main body. The deformation portion is deformed so as to be expanded outwardly in accordance with the expansion of the secondary lumen.

TECHNICAL FIELD

The invention relates to an introducer sheath and a method for using the same, and more particularly to an introducer sheath for introducing a plurality of catheters into a biological lumen and a method for using the same.

BACKGROUND DISCUSSION

In the medical field, a catheter which can be inserted into a lesion area along a biological lumen, for example, blood vessels, bile ducts, trachea, esophagus, or urethra in order to treat the lesion area generated in the biological lumen has been used. In general, the catheter is introduced into a biological lumen from an approach site which is formed by puncturing a living body. An introducer sheath which internally has a lumen is disposed on the approach site, and a catheter is introduced into a biological lumen through this introducer sheath. Accordingly, it is possible to insert a catheter into a biological lumen without directly causing friction between the catheter and biological tissues when treating a lesion area.

In recent years, the method of treating a lesion area in a biological lumen has become complicated. For example, in some cases, when treating chronic total occlusion (CTO) occurring in a blood vessel or the like, two catheters are simultaneously inserted into the blood vessel from both sides of the lesion area to treat the lesion area by the combined operation of the two catheters. At this time, it is necessary to form approach sites by puncturing two sites in order to insert the two catheters into the blood vessel and this has become a great burden on a person to be treated.

For example, JP-A-1-94863 discloses a catheter introducer for simultaneously inserting a plurality of catheters into a biological lumen from one approach site. The catheter introducer has one introducer sheath and a plurality of hubs which communicate with a lumen of the introducer sheath through an introduction passage. Accordingly, a plurality of catheters which have been respectively inserted into the plurality of hubs are guided into the one introducer sheath and are introduced into a biological lumen through the lumen in the introducer sheath. For this reason, only one approach site is formed in a person to be treated, and therefore, it is possible to reduce the burden on the person to be treated.

However, the lumen of the introducer sheath is formed to have a size that allows simultaneous insertion of a plurality of catheters, and therefore, it is also necessary to form the outer peripheral portion of the introducer sheath to be large in accordance with the size of the lumen. For this reason, even when using a small number of catheters with respect to the number of catheters which can be inserted into the introducer sheath, and for example, even when using only one catheter, the outer peripheral portion of the introducer sheath has the same size as that when using the set number of catheters. An approach site which is formed in a person to be treated through puncturing is formed in accordance with the size of this introducer sheath. Thus, even when using a small number of catheters, it is necessary to form the approach site having the same size as that when using the set number of catheters. Therefore, there is a disadvantage in that the size of the approach site is formed to be unnecessarily large.

SUMMARY

The disclosure herein provides an introducer sheath which can form an approach site having a size in accordance with the number of catheters to be inserted into a biological lumen and a method for using the same.

Hereinafter, the disclosure will be described using an introducer sheath having two lumens into which two catheters can be simultaneously inserted, as an example.

An introducer sheath for introducing a plurality of catheters into a biological lumen according to the disclosure, includes a sheath main body having a deformation portion which is disposed so as to include at least a part of an outer peripheral portion of the sheath main body; a primary lumen which is formed in the sheath main body; and a secondary lumen which is formed so as to be expandable in the sheath main body, in which the deformation portion is deformed so as to be expanded outwardly in accordance with the expansion of the secondary lumen. With such a configuration, it is possible to change the size of the outer peripheral portion of the introducer sheath in accordance with the number of catheters to be inserted into a blood vessel. Therefore, it is unnecessary to form a larger than necessary approach site in a person to be treated through puncturing, and thus, it is possible to reduce the burden on the person to be treated.

It is preferable that the secondary lumen is formed in the sheath main body in a state of being contracted into a small shape and is expanded by the inner peripheral surface being pressed outwardly. With the formation of the secondary lumen in a sheath main body in a state of being contracted into a small shape, it is possible to reduce the size of the outer peripheral surface of an introducer and to reduce the burden on a person to be treated when inserting the introducer into a blood vessel. In addition, it is possible to expand the secondary lumen with a simple operation, for example, insertion of a dilator, a balloon catheter, or the like into the secondary lumen.

In addition, the deformation portion may be configured so as to be deformed in accordance with the expansion of the secondary lumen and to maintain the expanded state of the secondary lumen. Accordingly, the expanded state of the secondary lumen is maintained even after the pressing for expanding the secondary lumen is released. Therefore, it is easy to introduce a diagnostic device, a therapeutic device, or the like into a lumen in a living body through the introducer sheath.

In addition, the sheath main body has a rigidity portion which is disposed in the vicinity of the primary lumen. The rigidity portion preferably has rigidity so as to maintain a predetermined diameter of the primary lumen. With such a configuration, it is possible to suppress kinking or the like of the introducer during insertion by enhancing the rigidity of the introducer and to suppress the influence of the expansion of the secondary lumen on the size of the diameter of the primary lumen. That is, it is possible to employ a configuration such that only the secondary lumen is deformed without deforming the primary lumen at all times. In such configuration, it is possible to dispose the rigidity portion so as to completely surround the periphery of the primary lumen.

In addition, it is possible to dispose the rigidity portion so as to surround a portion other than a boundary portion between the primary lumen and the secondary lumen, and the boundary portion can thus be deformed so as to be moved into the primary lumen in accordance with the expansion of the secondary lumen.

The deformation portion has a folding portion, which is constituted such that at least a part of the inner peripheral portion of the secondary lumen is folded, and may be deformed so as to be expanded outwardly through release of the folding of the folding portion in accordance with the expansion of the secondary lumen. Accordingly, it is possible to set the maximum diameter during the expansion of the secondary lumen and to prevent the diameter of the secondary lumen from unnecessarily increasing during the expansion.

The deformation portion may be configured such that at least a part of the outer peripheral portion of the sheath main body is folded, and be deformed so as to be expanded outwardly through release of the folding in accordance with the expansion of the secondary lumen. Accordingly, it is possible to set the maximum outer diameter during the expansion of the sheath main body and to suppress an increase in burden on a person to be treated due to an unnecessarily increased outer diameter of the sheath main body during the expansion. In addition, it is possible to reduce the size of the outer peripheral surface of the sheath main body by folding the outer peripheral portion of the sheath main body and to reduce the burden on a person to be treated when inserting the sheath main body into a blood vessel.

In addition, a separation film crossing the inside of the sheath main body may be provided along the sheath main body, and the primary lumen and the secondary lumen may be respectively formed in spaces which are divided by the separation film. The shape of the separation film may be either a linear shape or a curved shape in a cross-sectional portion of the sheath main body, and the primary lumen and the secondary lumen can be formed in the sheath main body with a simple configuration, for example, by provision of the separation film.

In addition, a cylindrical member is disposed along the inner peripheral surface of the sheath main body, the primary lumen is formed in an internal space of the cylindrical member which is disposed along the sheath main body, and the secondary lumen is formed in a space between the inner peripheral surface of the sheath main body and the outer peripheral surface of the cylindrical member. Accordingly, it is easy to set the size of the diameter of the primary lumen and it is possible to form the primary lumen and the secondary lumen with a simple configuration.

A method of using an introducer sheath according to the disclosure herein, includes indwelling the introducer sheath as described above into a biological lumen; introducing a first catheter into the biological lumen through a primary lumen which is formed in a sheath main body; expanding a secondary lumen which is formed so as to be expandable in the sheath main body; deforming a deformation portion, which is disposed so as to include at least a part of the outer peripheral portion of the sheath main body, so as to be expanded outwardly in accordance with the expansion of the secondary lumen; and introducing a second catheter into the biological lumen through the expanded secondary lumen.

According to the disclosure, the deformation portion which is disposed so as to include at least a part of the outer peripheral portion of the sheath main body is deformed so as to be expanded outwardly in accordance with the expansion of the secondary lumen. Therefore, it is possible to form an approach site having a size in accordance with the number of catheters to be inserted into a biological lumen.

DETAILED DESCRIPTION

Hereinafter, embodiments of the disclosure will be described based on the accompanying drawings. Note that, common features are identified by the same reference numerals throughout and so detailed descriptions of already described features will not be repeated. In some cases, dimensional ratios in the drawings are exaggerated and are different from the actual ratios for the convenience of description.

The introducer sheath is a device for securing an access route into a lumen in a living body. Note that, in the description below, the hand operation unit side of the device will be referred to as a “proximal side”, and the side through which the device is inserted into the lumen in a living body will be referred to as a “distal side”.

FIG. 1shows an introducer sheath1according to a first exemplary embodiment of the disclosure herein. The introducer sheath1has a sheath main body6for inserting two catheters into a blood vessel; two hubs2and3which are disposed at a proximal end of the sheath main body6; and three-way stopcocks4and5which are provided in the hubs2and3.

The sheath main body6has an elongated shape, and as shown inFIG. 2, a primary lumen7and a secondary lumen8, which extend from a proximal end to a distal end, are formed inside the sheath main body6.

The primary lumen7communicates with a port9which is formed in the hub2, and therefore, it is possible to insert a catheter into the primary lumen7by introducing the catheter through the port9. In addition, the secondary lumen8communicates with a port10which is formed in the hub3. In addition, a hemostatic valve (not shown), which is formed of an elastic member is liquid-tightly fixed to the hub2and the hub3, and is configured such that blood does not leak from the port9and the port10after indwelling an introducer sheath in a blood vessel.

The three-way stopcock4is connected to the port9of the hub2, and therefore, it is possible to inject heparin or a physiological salt solution using a syringe or the like and to fill the primary lumen7with these solutions. Similarly, a three-way stopcock5is connected to the port10of the hub3, and therefore, it is possible to inject heparin or a physiological salt solution into the secondary lumen8.

Next, the configuration of the sheath main body6will be described in detail.

The primary lumen7and the secondary lumen8are disposed in the sheath main body6so as to be adjacent to each other as shown inFIG. 2. The primary lumen7has a size that allows insertion of one catheter thereinto, and is formed so as to occupy most of the cross-sectional area in the sheath main body6. In contrast, the secondary lumen8is formed in a state of being contracted into a small shape so as not to affect the size of the outer peripheral portion of the sheath main body6. For example, the secondary lumen8can be formed to have a size small (diameter of about 0.5 mm) enough to pass a guide wire therethrough. In this manner, it is possible to make the outer peripheral portion of the sheath main body6have a size approximately the same as that in a case of forming only the primary lumen7therein by forming the secondary lumen8in a state of being contracted into a small shape.

In addition, a rigidity portion11is disposed in the sheath main body6so as to completely surround the periphery of the primary lumen7, and a deformation portion12is further disposed so as to cover the rigidity portion11. The rigidity portion11has rigidity so as to support the sheath main body6from inside and to maintain a predetermined diameter of the primary lumen7. Note that the rigidity portion11preferably has flexibility to some degree so as to be bent along a blood vessel. The rigidity portion11can be formed of, for example, a metal, such as, pseudoelastic alloy, shape memory alloy, and stainless steel, or a resin, such as, polyolefin, polyvinyl chloride, and polyamide.

In contrast, the deformation portion12constitutes the entirety of the outer peripheral portion of the sheath main body6and the secondary lumen8is disposed inside the deformation portion. The deformation portion12is formed to have sufficient flexibility for being deformed in accordance with the expansion of the secondary lumen8and slidability between the inner surface of the secondary lumen8and the outer surface of a medical instrument, for example, a dilator or a catheter when the medical instrument is inserted into the secondary lumen8. Accordingly, the secondary lumen8is expanded only when a medical instrument is inserted into the secondary lumen8, and therefore, the burden on a patient decreases. With the insertion of the medical instrument into the secondary lumen8, the deformation portion12is deformed so as to be expanded outwardly as shown inFIG. 2, and accordingly, the outer peripheral portion of the sheath main body6is pressed and expanded outwardly. As shown inFIG. 3, the secondary lumen8can be expanded until the secondary lumen has a size substantially the same as that of the primary lumen7. Note that the deformation portion12can be formed of a flexible member, for example, natural rubber or synthetic rubber. At this time, a coating may be applied to the inner peripheral surface of the secondary lumen8in order to improve the slidability.

The deformation portion12may have flexibility for being deformed in accordance with the expansion of the secondary lumen8and plasticity for maintaining the expanded state of the secondary lumen8. Accordingly, the secondary lumen8is expanded by the inner peripheral surface being pressed outwardly, and it is possible to maintain the expanded state to some degree even after the pressing is released. The deformation portion12is deformed so as to be expanded outwardly in accordance with the expansion of the secondary lumen8, and accordingly, the outer peripheral portion of the sheath main body6is pressed and expanded outwardly. The secondary lumen8can be expanded until the secondary lumen has a size substantially the same as that of the primary lumen7. The deformation portion12can have, for example, a folding portion which is configured such that at least a part of the inner peripheral portion of the secondary lumen8is folded. Accordingly, the secondary lumen8can be formed in the sheath main body in a state of being contracted into a small shape. For example, as shown inFIG. 4, in the deformation portion12, a plurality of folding portions8a, which are folded with the inner peripheral surface of the secondary lumen8facing the inside, can be formed over the entire periphery of the secondary lumen8. With such a configuration, it is possible to expand the secondary lumen8while releasing the folding of the folding portions8adue to pressing from the inside by inserting a medical instrument into the secondary lumen8. In this manner, it is possible to maintain the expanded state of the enlarged secondary lumen8to some degree even after the pressing from the inside due to a medical instrument is released. By way of example, the deformation portion12can be formed of a synthetic resin, for example, polyolefin, polyvinyl chloride, and polyamide. In addition, even in a case where the deformation portion12does not have the folding portions8a, by disposing a wire having malleability in the deformation portion12in the vicinity of the secondary lumen8which is expanded by the inner peripheral surface being pressed outwardly, it is possible to maintain the expanded state of the secondary lumen8even after the pressing is released.

Next, the operation of exemplary embodiment one will be described.

First, only one predetermined site of a person to be treated is punctured to form an approach site S, and a guide wire Wo1(mini guide wire) is inserted into a blood vessel V through the approach site S. A dilator D1is inserted into the introducer sheath1shown inFIG. 1through the port9which is formed in the hub2, and a distal portion of the dilator D1protrudes from a distal end of the introducer sheath1through the primary lumen7. The introducer sheath1in which the dilator D1has been installed in this manner is then inserted into a blood vessel V as shown inFIG. 5along the guide wire Wo1which has been previously inserted into the blood vessel V.

When the introducer sheath1is inserted into a predetermined position in the blood vessel V along the guide wire Wo1, the introducer sheath1is indwelled in the blood vessel and the dilator D1and the guide wire Wo1are pulled out from the introducer sheath1. Subsequently, another guide wire Wa is introduced through the port9of the hub2and a distal portion of the guide wire Wa is delivered to the vicinity of a target lesion area. Then, a first catheter Ka is introduced through the port9of the hub2. The introduced first catheter Ka is led out from the distal end of the introducer sheath1through the primary lumen7as shown inFIGS. 6aand 6band is inserted into a blood vessel V along the guide wire Wa.

Here, the primary lumen7has a size that allows insertion of one catheter, but the secondary lumen8maintains a state of being contracted into a small shape so as not to affect the size of the sheath main body6. For this reason, the outer peripheral portion of the sheath main body6has a size substantially the same as that when only the primary lumen7is formed therein, that is, a size substantially the same as that of a sheath for inserting one catheter. Accordingly, when inserting only the first catheter Ka into a blood vessel V, it is unnecessary to form a large approach site S into which two catheters are inserted, and it is possible to form the approach site S at a size L1approximately the same as that when inserting one catheter.

In this manner, it is possible to deliver a distal portion of the first catheter Ka to a target lesion area by inserting the first catheter Ka into the blood vessel V along the guide wire Wa and to treat the lesion area using the first catheter Ka. Note that it is possible to fill the primary lumen7by injecting a solution, for example, heparin through the three-way stopcock4, and thus, it is possible to suppress solidification of blood which has flowed into the primary lumen7by filling the primary lumen7with heparin.

Subsequently, in a case of treating the lesion area in the blood vessel V using two catheters, a guide wire Wo2(mini guide wire) is inserted into the secondary lumen8of the introducer sheath1from the port10which has been formed in the hub3of the sheath assembly, a dilator D2is inserted thereinto along the guide wire Wo2, and then, the guide wire Wo2and the dilator D2are led out from the distal end of the introducer sheath1as shown inFIG. 7. At this time, the dilator D2is inserted into the introducer sheath1while pressing the inner peripheral surface of the sheath main body6so as to press and expand the secondary lumen8. Accordingly, the secondary lumen8is expanded so as to have a size substantially the same as that of the primary lumen7, the deformation portion12is deformed so as to be expanded outwardly in accordance with the expansion of the secondary lumen8, and the outer peripheral portion of the sheath main body6is pressed and expanded outwardly. For this reason, the outer peripheral portion of the sheath main body6is significantly deformed and the approach site S which has been formed in a person to be treated is also expanded in accordance with the deformation.

Note that the dilator D2has been used in order to expand the secondary lumen8. However, an expansion device, for example, a balloon catheter may be used as long as it is possible to expand the secondary lumen8.

The dilator D2is pulled out from the inside of the introducer sheath1when the secondary lumen8in the introducer sheath1is expanded in this manner. Then, another guide wire Wb is introduced through the port10of the hub3and a distal portion of the guide wire Wb is delivered to the vicinity of a target lesion area. Subsequently, a second catheter Kb is introduced through the port10of the hub3. At this time, the secondary lumen8is flexible and has high slidability on the inner peripheral surface thereof. Therefore, it is possible to smoothly insert the second catheter Kb even after the dilator D2is removed. That is, the second catheter Kb which has been introduced through the port10of the hub3can be smoothly inserted into the secondary lumen8without receiving a large amount of pressure from the inner peripheral surface of the deformation portion12constituting the secondary lumen8. In this manner, the second catheter Kb is led out from the distal end of the introducer sheath1through the expanded secondary lumen8as shown inFIGS. 8aand 8band is inserted into a blood vessel V along the guide wire Wb.

In this instance, the outer peripheral portion of the introducer sheath1is pressed and expanded outwardly by the amount equivalent to the expansion of the secondary lumen8. Therefore, the size of the outer peripheral portion of the introducer sheath becomes substantially the same as that of a sheath for inserting two catheters without significantly expanding the outer peripheral portion more than necessary. For this reason, the approach site S formed in a person to be treated is formed at a size L2substantially the same as that when inserting the two catheters, and therefore, it is unnecessary to expand the size larger than the size L2.

In this manner, it is possible to deliver a distal portion of the second catheter Kb to a target lesion area by inserting the second catheter Kb into the blood vessel V along the guide wire Wb and to treat the lesion area using the two catheters of the first catheter Ka and the second catheter Kb. Note that it is possible to suppress solidification of blood which has flowed in terms of the secondary lumen8by injecting a solution, for example, heparin through the three-way stopcock5.

According to the first exemplary embodiment, the size of the outer peripheral portion of the introducer sheath1can be changed in accordance with the number of catheters to be inserted into the blood vessel V. For this reason, the approach site S which is formed in a person to be treated through puncturing can be formed to have a size of one catheter when inserting one catheter thereinto and a size of two catheters when inserting two catheters. Therefore, it is unnecessary to form a larger than necessary approach site S, and thus, it is possible to reduce the burden on the person to be treated.

Note that, in the aforesaid exemplary embodiment, the deformation portion12is formed so as to constitute the entirety of the outer peripheral portion of the sheath main body6. However, the deformation portion12may be formed to include only a part of the outer peripheral portion of the sheath main body6as long as it is possible to expand the outer peripheral portion of the sheath main body6outwardly in accordance with the expansion of the secondary lumen8.

In addition, in the aforesaid exemplary embodiment, one primary lumen7and one secondary lumen8are formed inside the sheath main body6. However, a plurality of lumens can be formed in accordance with the number of catheters to be used for treating a lesion area in a blood vessel. For example, a plurality of secondary lumens8can be formed with respect to one primary lumen7.

In addition, in the aforesaid exemplary embodiment, the rigidity portion11is disposed so as to completely surround the periphery of the primary lumen7. However, the disclosure herein is not limited thereto as long as it is possible to maintain the size that allows insertion of the first catheter Ka through the primary lumen7.

For example, as shown inFIG. 9a, it is possible to dispose a rigidity portion14along a portion of the periphery of the primary lumen7, instead of the rigidity portion11of the first embodiment, so as to surround a portion which does not include a boundary portion13between the primary lumen7and the secondary lumen8. A deformation portion15is disposed so as to cover the rigidity portion14and to include the boundary portion13. Accordingly, when the secondary lumen8is expanded by inserting a dilator D2into the secondary lumen, the outer peripheral portion of the sheath main body6is deformed so as to be expanded outwardly in accordance with the expansion, and the boundary portion13is deformed so as to be moved into the primary lumen7. That is, the boundary portion13is deformed so as to reduce the size of the primary lumen7by also being expanded to the primary lumen7side while being deformed so as to be expanded outwardly in accordance with the expansion of the secondary lumen8. As shown inFIG. 9b, it is possible to insert the second catheter Kb into the expanded secondary lumen8and to insert the second catheter Kb which is led out from the introducer sheath1through the secondary lumen8into the blood vessel V.

In this manner, the boundary portion13is expanded to the primary lumen7side as well as the outer peripheral portion of the sheath main body6being outwardly expanded in accordance with the expansion of the secondary lumen8. Therefore, it is possible to further reduce the outer peripheral portion of the introducer sheath1when inserting the two catheters. For this reason, it is possible to reduce the size of the approach site S to be formed in a person to be treated and to further reduce the burden on the person to be treated.

In the first exemplary embodiment, the flexible deformation portion12which is deformed in accordance with the expansion of the secondary lumen8is disposed in the sheath main body6. However, the disclosure herein is not limited thereto as long as it is possible to expand the outer peripheral portion of the sheath main body6outwardly in accordance with the expansion of the secondary lumen8.

For example, as shown in the second exemplary embodiment ofFIG. 10a, a sheath main body21has a deformation portion22in which a part of the outer peripheral portion is folded. It is possible to expand the outer peripheral portion of the sheath main body21outwardly by releasing the folding of the deformation portion22in accordance with the expansion of the secondary lumen8. Specifically, a rigidity portion23is disposed so as to surround the entirety of the outer peripheral portion of the sheath main body21and the deformation portion22is disposed on a part of the rigidity portion23. The rigidity portion23has rigidity so as to support the sheath main body21from outside when inserting the sheath main body21into a blood vessel. The rigidity portion can be formed of, for example, a metal, such as, pseudoelastic alloy, shape memory alloy, and stainless steel, or a resin, such as, polyolefin, polyvinyl chloride, and polyamide. Note that the rigidity portion23preferably has flexibility to some degree so as to be bent along a blood vessel.

The deformation portion22is formed by folding the rigidity portion23inwardly so as to overlap the folded portions of the rigidity portion with each other. The overlapping portions of the rigidity portion23are bonded to each other such that the folding is held in place. The folding of the deformation portion22can be released by disengaging the bonding by pressing the inner peripheral surface of the rigidity portion23outwardly with a predetermined amount of pressure.

In addition, a separation film24crossing the inside of the rigidity portion23is formed along the sheath main body21such that the inside is divided by the separation film24into the primary lumen7and the secondary lumen8. That is, the primary lumen and the secondary lumen are respectively formed in spaces which are divided by the separation film24. In a state where the deformation portion22is folded, the primary lumen7has a size that allows insertion of the first catheter Ka, and is formed so as to occupy most of the inside of the sheath main body21. In contrast, through the folding of the deformation portion22, the secondary lumen8is formed in a state of being contracted into a small shape so as not to affect the size of the outer peripheral portion of the sheath main body21. For example, the secondary lumen8can be formed to have a size small (diameter of about 0.5 mm) enough to pass a guide wire therethrough.

Note that the size of the primary lumen7and the secondary lumen8in a state where the folding of the deformation portion22is released can be changed depending on the position of the separation film24. For example, in a cross section of the sheath main body21, in a case where a linear separation film24which passes a middle point of the shape of the cross section thereof is provided, the sizes of the primary lumen7and the secondary lumen8in the state where the folding is released become substantially the same as each other. Note that the separation film24may have enough strength or flexibility to avoid any damage due to insertion of a medical instrument, for example, a dilator or a catheter and can be formed of resin, for example, polyolefin, polyvinyl chloride, and polyamide.

The separation film24has enough strength or flexibility to avoid any damage due to expansion of the secondary lumen8. Therefore, the folding of the deformation portion22is released when the inner peripheral surface of the rigidity portion23is pressed outwardly with a predetermined amount of pressure by a medical instrument which has been inserted into the secondary lumen8and the secondary lumen is then expanded. The deformation portion22is deformed so as to be expanded outwardly in accordance with the expansion of the secondary lumen8and the outer peripheral portion of the sheath main body21is pressed and expanded outwardly. Accordingly, it is possible to press and expand the outer peripheral portion of the sheath main body21outwardly in accordance with the expansion of the secondary lumen8.

For example, in a cross section of the sheath main body21, in a case where a linear separation film24passes a middle point of the shape of the cross section thereof, as shown inFIG. 10b, it is possible to expand the size of the secondary lumen8to be substantially the same as that of the primary lumen7and to insert the second catheter Kb having the same size as that of the first catheter Ka which is inserted into the primary lumen7, into the expanded secondary lumen8.

According to the disclosure herein, it is possible to change the size of the outer peripheral portion of the introducer sheath1in accordance with the number of catheters to be inserted into the blood vessel V. Therefore, it is unnecessary to form a large approach site S which is formed in a person to be treated through puncturing, and thus, it is possible to reduce the burden on the person to be treated. In addition, the rigidity portion23is disposed so as to surround the entirety of the outer peripheral portion of the sheath main body21. Therefore, it is possible to improve piercing properties of the introducer sheath1and to smoothly insert the introducer sheath1into a blood vessel through the approach site S.

In addition, with reference toFIG. 11a, it is possible to configure an introducer sheath which can form two lumens through which catheters can be inserted by expansion of the secondary lumen8without using the separation film24in the introducer sheath as in the second exemplary embodiment described above.

InFIG. 11a, the separation film24is removed from the sheath main body21of the second embodiment, and a cylindrical member25is provided instead inside the rigidity portion23along the inner peripheral surface of the sheath main body21, and the primary lumen7is formed in an internal space of the cylindrical member25. Moreover, the secondary lumen8is formed by a space which can be formed between the outer periphery of the cylindrical member25and the inner periphery of the rigidity portion23.

In the third embodiment ofFIGS. 11aand 11b, when the deformation portion22is in a state of being folded, the rigidity portion23is disposed so as to cover the outer periphery of the cylindrical member25. For this reason, even if the deformation portion22is in a state of being folded, the primary lumen7has a size that allows insertion of the first catheter Ka, and is formed so as to occupy most of the cross-sectional area in the sheath main body21. The secondary lumen8is formed in a state of being contracted into a small shape so as not to affect the size of the outer peripheral portion of the sheath main body21, through the folding of the deformation portion22. For example, the secondary lumen8can be formed to have a size small (diameter of about 0.5 mm) enough to pass a guide wire therethrough.

Note that the cylindrical member has enough rigidity to avoid crushing in accordance with the expansion of the secondary lumen8and can be formed of, for example, a metal, such as, pseudoelastic alloy, shape memory alloy, and stainless steel, or a resin, such as, polyolefin, polyvinyl chloride, and polyamide. Note that the rigidity portion23preferably has flexibility to some degree so as to be bent along a blood vessel.

The cylindrical member has enough rigidity to avoid crushing due to expansion of the secondary lumen8. Therefore, the folding of the deformation portion22is released when the inner peripheral surface of the rigidity portion23is pressed outwardly with a predetermined amount of pressure by a medical instrument which has been inserted into the secondary lumen8which is then expanded. The deformation portion22is deformed as shown inFIG. 11bso as to be expanded outwardly in accordance with the expansion of the secondary lumen8and the outer peripheral portion of the sheath main body21is pressed and expanded outwardly. Accordingly, it is possible to press and expand the outer peripheral portion of the sheath main body21outwardly in accordance with the expansion of the secondary lumen8.

According to the third exemplary embodiment, similar to the second embodiment, it is possible to change the size of the outer peripheral portion of the introducer sheath1in accordance with the number of catheters to be inserted into the blood vessel V. Therefore, it is unnecessary to form an approach site S larger than necessary in a person to be treated through puncturing, and thus, it is possible to reduce the burden on the person to be treated. In addition, the rigidity portion23is disposed so as to surround the entirety of the outer peripheral portion of the sheath main body21. Therefore, it is possible to improve piercing properties of the introducer sheath1and to smoothly insert the introducer sheath1into a blood vessel through the approach site S.

Note that the rigidity portion23of the second and third exemplary embodiments may be configured such that the folding of the deformation portion22is released by the inner peripheral surface being pressed outwardly, and can be formed of a material with low rigidity to some degree so as to facilitate the folding of the deformation portion22.

Note that, in the aforesaid first, second and third embodiments, the introducer sheath1is used in order to introduce a catheter into a blood vessel of a person to be treated. However, the introducer sheath can also be used in order to introduce a catheter into biological lumens, for example, bile ducts, trachea, esophagus, and urethra.

The detailed description above describes an introducer sheath and a method of using the same. The disclosure is not limited, however, to the precise embodiments and variations described. Various changes, modifications and equivalents can be effected by one skilled in the art without departing from the spirit and scope of the invention as defined in the accompanying claims. It is expressly intended that all such changes, modifications and equivalents which fall within the scope of the claims are embraced by the claims.