Patent Description:
Patients with cardiac ailments are sometimes treated with a percutaneous mechanical irculatory support device, also commonly referred to as a heart pump, configured to assist the natural cardiac pump function or to replace natural cardiac pump function by a continuous pumping operation. These heart pump assemblies can be introduced surgically or percutaneously during a cardiac procedure through the vascular system, such as through blood vessels. In one common approach, pump assemblies are inserted via a catheterization procedure through the femoral artery using an introducer sheath.

The introducer sheath can provide a reliable access point for the introduction of heart pump assemblies as well as a wide range of diagnostic and therapeutic interventional catheter-based devices. The introducer sheath can be inserted into an artery or vein, and the pump can be advanced through the introducer sheath into the patient. The introducer sheath can then be separated into two halves along a break wall and peeled away while the pump, catheter, and/or guidewire is left in place. This allows physicians to perform clinical procedures that require separation/removal of the introducer sheath without disturbing the position of a pump, catheter, guidewire, and/or other device that has been introduced into and should remain positioned inside of the body.

As percutaneous heart pumps have become larger and more sophisticated, the introducer sheaths for introduction of the pumps into the body have also necessarily become larger. The larger introducer sheath and hub assembly require a greater breaking force to split the hub of the introducer sheath (e.g., because the thickness of the break wall is greater). The increased break force can make fracturing the hub difficult and less reliable. Furthermore, the increased break force can lead to abrupt breaks of the hub which may undesirably jostle, dislodge, or damage the pump, and/or may in some cases cause discomfort or injury to the healthcare physician administering treatment. Prior art introducer assemblies are for instance disclosed in documents <CIT> and <CIT>.

According to the invention, an introducer assembly comprising the technical features of claim <NUM> is provided. Disclosed herein is an introducer sheath having a multi-layer hub for percutaneous insertion of a heart pump. The hub can include two or more hub portions formed of different materials so as to reduce the break force required to split the peel-away introducer. The hub has a first hub portion and a second hub portion partially surrounding the first hub portion. The first hub portion includes one or more notches along which the hub is configured to split. The second hub portion includes wings or tabs positioned on either side of the hub which are used as leverage for applying the break force. The first hub portion may be formed of a soft material having a low ultimate strength, while the second hub portion may be formed of a relatively stiff material having an ultimate strength higher than that of the first hub portion. In such a configuration, the soft first hub portion allows the hub to be easily split along the notches in the first material, while the stiff second hub portion has stiff wings which provide improved leverage during breaking. The stiff wings do not bend or flex excessively when a force is applied, but instead transfer applied loads to the notches, thereby facilitating splitting of the introducer. The stiffer wings also reduce the amount of elastic energy that is stored when force is applied to the wings during splitting of the introducer hub. This reduces the sudden release of elastic energy when the hub is split, thereby reducing the risk of displacing or damaging the pump, or causing discomfort or injury to the patient or physician. Thus, by using two hub portions of differing material properties, the systems, methods, and devices described herein can facilitate splitting of the peel-away introducer sheath. By maintaining a low break force, the multilayer hub enables use of wider bore introducer sheathes which would otherwise be too difficult to split.

The second hub portion may be over-molded on the first hub portion. The overmolding may form a hemostatic bond between the first hub portion and the second hub portion. To strengthen the bond between the two portions, the first hub portion may also include ridges or grooves over which the second hub portion is molded. This can increase the amount of torque that the second hub portion can transmit to the first hub portion without failure of the bond. Additionally, the second hub portion may include an opening above the one or more notches in the first hub portion. This opening allows the first hub portion to easily split in the region of the notch or notches, thus preserving the low break force of the hub.

In one aspect, an introducer assembly comprises an elongate sheath and a hub. The elongate sheath is sized for insertion into a blood vessel of a patient and includes a longitudinal axis. The hub is coupled to a proximal portion of the sheath and comprises a first hub portion and a second hub portion. The first hub portion comprises a first notch. The second hub portion partially surrounds the first hub portion and comprises two wings and an opening disposed above the first notch. The first hub portion comprises a first material and the second hub portion comprises a second material, wherein the first material differs from the second material. The first material has a first ultimate strength and the second material has a second ultimate strength. The second ultimate strength is greater than the first ultimate strength. In some implementations, the first material has a first stiffness and the second material has a second stiffness, the second stiffness being greater than the first stiffness.

In some implementations, the first notch is oriented parallel to the longitudinal axis of the elongate sheath. In certain implementations, the hub is configured to break at the first notch along the direction of the longitudinal axis of the elongate sheath. In some implementations, the elongate sheath has a longitudinal scoring parallel to the longitudinal axis of the elongate sheath. The elongate sheath may be configured to tear along the longitudinal scoring parallel to the longitudinal axis of the elongate sheath.

In some implementations, the first hub portion includes ridges. In some implementations, the first hub portion and the elongate sheath form a hemostatic bond. In certain implementations, the wings comprise a wide face and a narrow face and the wide face is normal to the longitudinal axis of the elongate sheath. In some implementations, the narrow face of the wings is normal to the longitudinal axis of the elongate sheath. In some implementations, the first hub portion further includes a second notch. In some implementations, the first hub portions include a first ridge and a second ridge which define edges of the first notch.

In some implementations, the first material has a hardness of about <NUM> Shore D. In certain implementations, the second material has a hardness of about <NUM>-<NUM> Shore D. In some implementations, the introducer hub has a minimum diameter of about <NUM> Fr. In other implementations, the introducer hub has a minimum diameter of about <NUM> Fr. In certain implementations, the first hub portion has a minimum thickness of about <NUM> at the first notch. In some implementations, the first hub portion has a maximum thickness of about <NUM> at the first notch.

In some implementations, the thickness of the first hub portion at the first notch is variable along a length of the notch. In some implementations, the thickness of the first hub portion at the first notch is greatest at a proximal end portion of the first notch. In some implementations, the thickness of the first hub portion at the first notch is between about <NUM> inches (<NUM> inch = <NUM>. ) and <NUM> inches at the proximal end of the first hub. In some implementations, the thickness of the first hub portion at the first notch is between about <NUM> inches and <NUM> inches at a distal end portion of the first hub.

To provide an overall understanding of the systems, methods, and devices described herein, certain illustrative embodiments will be described. Although the embodiments and features described herein are specifically described for use in connection with introducer sheaths for percutaneous insertion of heart pumps, it will be understood that all the components and other features outlined below may be combined with one another in any suitable manner and may be adapted and applied to other types of introducer sheaths, other types of cardiac assist devices, or for the delivery of any suitable catheter, guide wire, surgical tool, or medical device.

The apparatus described herein includes an introducer and a hub assembly for the introducer (where the introducer can be used, e.g., for percutaneous insertion of a heart pump). In an embodiment of the invention, the hub has a first hub portion and a second hub portion partially surrounding the first hub portion. In an example not according to the invention, the hub does not have a first hub portion and a second hub portion partially surrounding the first hub portion. In an embodiment of the invention, the first hub portion includes a notch along which the hub can be configured to fracture or split. In an example not according to the invention, the first hub portion does not include a notch along which the hub can be configured to fracture or split. In an embodiment of the invention, the second hub portion includes wings or tabs which are positioned on opposite sides of the hub and may be used as leverage for applying the break force. In an example not according to the invention, the second hub portion does not include wings or tabs which are positioned on opposite sides of the hub and may be used as leverage for applying the break force. The first hub portion can be formed of a soft material having a low ultimate strength, while the second hub portion can be formed of a relatively stiff material having an ultimate strength that is higher than an ultimate strength of the first hub portion. In such a configuration, the soft first hub portion can allow the hub to be easily fractured or split along the notch in the first material, while the wings of the stiff second hub portion provide improved leverage during breaking. The stiffness of the wings is selected so that the wings do not bend or flex excessively when pressure is applied and instead transfer applied loads to the notches, thereby facilitating splitting of the introducer. The stiffer wings can also reduce the amount of elastic energy that is stored when force is applied to the wings during splitting of the introducer hub. This reduces the sudden release of elastic energy when the hub is split, thereby reducing the risk of displacing or damaging the pump, and/or injuring the patient or physician. Thus, by using two hub portions with differing material properties, the systems, methods, and devices described herein can facilitate splitting of the introducer sheath. By maintaining a low break force, the multilayer hub enables use of introducer sheathes having larger dimensions and/or a larger bore which would otherwise be too difficult to split.

The hub assembly can be manufactured in various ways and can include different combinations of features. For example, the second hub portion can be over-molded on the first hub portion. The over-molding can form a bond between the first hub portion and the second hub portion that prevents blood from passing through the interface between the first hub portion and the second hub portion. In particular, the bond formed by the over-molding may be a chemical and/or molecular bond. If the first hub portion is formed of a polymer similar to a polymer from which the second hub portion is formed, the polymer chains of the two materials may cross-link at the interface between the first hub portion and second hub portion. -<NUM>-
55227759_1
Alternatively, the first and second hubs can be molded separately and then bonded together using any technique known in the art, such as using chemical adhesive. In either instance, the first hub portion may also include ridges or grooves to strengthen the bonding between the first and second hub portions by increasing the surface area for polymer cross-linking and/or to provide a mechanical interlock between the first and second hub portions. This can increase the amount of force that the second hub portion can transmit to the first hub portion without failure of the bond. For another example, the second hub portion may include an opening above the one or more notches in the first hub portion. This opening allows the first hub portion to easily split in the region of the notch, thus preserving the low break force of the hub. By maintaining a low break force, the systems, methods, and devices described herein thus allow introducer hubs to be made larger to accommodate large heart pumps while still breaking apart with application of a reasonable amount of force.

<FIG> shows a top-down view of the introducer hub assembly <NUM> including an elongate sheath <NUM> and a hub <NUM>. The elongate sheath <NUM> is sized for insertion into a blood vessel of a patient and has a longitudinal axis <NUM>. The hub <NUM> includes a first hub portion <NUM> having a first notch <NUM>, and a second hub portion <NUM> having an opening <NUM> and two wings 18a and 18b. The opening <NUM> is disposed above the first notch <NUM>. The first notch <NUM> in the first hub portion <NUM> is in some implementations aligned with or at least partially parallel to the longitudinal axis <NUM> of the elongate sheath <NUM>. The second hub portion <NUM> partially covers the first hub portion <NUM>. In some implementations, the second hub portion <NUM> is over-molded onto the first hub portion <NUM>. The second hub portion <NUM> includes an opening <NUM> above the first notch <NUM> which exposes the first notch <NUM>.

The first notch <NUM> formed in the first hub portion <NUM> provides a break wall at which a crack may be initiated in the hub <NUM> by applying force to the wings 18a and 18b. The first notch <NUM> may be formed in a first material having a relatively low ultimate strength break force. Furthermore, the first notch <NUM> may be formed such that a thickness of the first material at the bottom of the first notch <NUM> permits breaking of the hub <NUM> at the first notch <NUM> at a reasonably low force. Additionally, the shape of the notch <NUM> may concentrate stress to facilitate splitting of the hub <NUM> along the notch <NUM>. In some implementations, the first hub portion <NUM> has a minimum thickness at the first notch <NUM> of <NUM>. In some implementations, the first hub portion <NUM> has a maximum thickness of <NUM> at the first notch <NUM>. In some implementations the first hub portion <NUM> has a thickness at the first notch <NUM> of <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or any other suitable thickness.

The second hub layer <NUM> partially surrounding the first hub layer <NUM> allows the wings 18a and 18b to be formed from a stiffer material. The stiff wings 18a and 18b allow a healthcare professional to apply force, such as a manual force, to break the hub <NUM> at the first notch <NUM>. After the hub is broken, the wings 18a and 18b can be pulled apart and used to peel away the introducer hub assembly <NUM> from the patient and any devices or guidewires extending through the vessel. In some implementations, the second hub portion <NUM> can be over-molded over the first hub assembly <NUM>.

During use, the introducer hub assembly <NUM> facilitates insertion of a heart pump or other medical object into a blood vessel of a patient. The introducer hub assembly <NUM> is designed as a peel-away introducer. The elongate sheath <NUM> is inserted into a blood vessel of the patient and the heart pump is advanced through the hub <NUM> and through the elongate sheath <NUM> into the patient. During removal of the introducer hub assembly <NUM>, the wings 18a and 18b can be grasped and a first force is applied by a user, e.g. a healthcare professional, toward the user to break the hub <NUM> along the first notch <NUM>. A second force may then be applied in a direction opposite the first force to break the hub <NUM> along a second notch (not shown). The introducer hub assembly <NUM>. including the hub <NUM> and elongate sheath <NUM>, is then peeled away, leaving the heart pump or other medical object undisturbed within the blood vessel of a patient.

<FIG> shows a perspective view of an illustrative introducer hub assembly <NUM>. The introducer hub assembly <NUM> includes an elongate sheath <NUM> and a hub <NUM>. The hub <NUM> includes a first hub portion <NUM> and a second hub portion <NUM>. The first hub portion <NUM> includes a first notch <NUM>, a proximal end portion <NUM>, and a distal end portion <NUM>. The second hub portion <NUM> includes an opening <NUM> above the first notch <NUM> and two wings 118a and 118b. The elongate sheath <NUM> includes a longitudinal axis <NUM> and an internal diameter <NUM> which is sized to allow a heart pump or medical device to be inserted through the elongate sheath <NUM> and into a blood vessel of a patient. The internal diameter <NUM> of the elongate sheath may be <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or any other suitable diameter. In some implementations, the inner diameter of the elongate introducer body <NUM> is compatible with devices that are <NUM> French (<NUM>), <NUM> French (<NUM>), <NUM> French (<NUM>), <NUM> French (<NUM>), <NUM> French (<NUM>), <NUM> French (<NUM>), <NUM> French (<NUM>), <NUM> French (<NUM>), <NUM> French (<NUM>), <NUM> French (<NUM>), <NUM> French (<NUM>), <NUM> French (<NUM>), <NUM> French (<NUM>), <NUM> French ( <NUM>), <NUM> French (<NUM>), <NUM> French (<NUM>), or any other suitable diameter. The first hub portion <NUM> lies closest to an outer surface <NUM> of the elongate sheath <NUM>. The first hub portion <NUM> includes a first notch <NUM> which is oriented to be parallel to the longitudinal axis <NUM> of the elongate sheath <NUM>. The first hub portion <NUM> also includes a first ridge 128a and a second ridge 128b which extend up from surface of the elongate sheath <NUM>, defining the first notch <NUM>. The second hub portion <NUM> partially surrounds the first hub portion <NUM> except at an opening <NUM> over the first notch <NUM>. In some implementations, the opening <NUM> is also over the first ridge 128a and second ridge 128b of the first hub portion <NUM> defining the first notch <NUM>. The second hub portion <NUM> includes two wings <NUM>18a and <NUM>18b which extend outward on either side of the hub <NUM>. Each of the two wings <NUM>18a and <NUM>18b is constructed to include a wide face 124a and 124b and a narrow face 125a and 125b. The two wings <NUM>18a and <NUM>18b may be oriented in a variety of directions. In some implementations, a wide face 124a and 124b of the wings 118a and 118b may be positioned to be normal to the longitudinal axis <NUM> of the elongate sheath <NUM>. In other implementations, a narrow face 125a and 125b of the wings 118a and <NUM>18b may be positioned to be normal to the longitudinal axis <NUM> of the elongate sheath <NUM>.

After the heart pump or medical device has been inserted into the patient, the introducer hub assembly <NUM> can be separated at the hub <NUM> along the length of the first notch <NUM> and at the elongate sheath <NUM> along the length of the longitudinal scoring <NUM>. The wings 118a and 118b are designed to be gripped by a healthcare professional for removal. The healthcare professional applies force to the first and second wings 118a and 118b to part (e.g. "peel-away") the introducer assembly <NUM>. This separates the hub <NUM> at the first notch <NUM> and the longitudinal scoring <NUM>, fracturing/breaking the hub <NUM> and elongate sheath <NUM> in half. In some implementations, the wings 118a and 118b are designed to be pressed in a downward motion toward the elongate sheath <NUM> to break the hub <NUM> at the first notch <NUM>. In such implementations, the wide face 124a and 124b of the wings 118a and 118b may be oriented to be normal to the longitudinal axis <NUM> of the elongate sheath <NUM>. In other implementations, the narrow face 125a and 125b of the wings 118a and 118b may be oriented to be normal to the longitudinal axis <NUM> of the elongate sheath <NUM> and may be designed such that forcing the two wings 118a and 118b toward each other facilitates the breaking of the first notch <NUM>. Once the hub <NUM> has been broken at the first notch <NUM>, each of the wings 118a and 118b may be peeled away from each other to remove the hub <NUM>. The elongate sheath <NUM> may also include a longitudinal scoring <NUM> parallel to the longitudinal axis <NUM> in line with the first notch <NUM> in the hub <NUM>. The elongate sheath <NUM> may be configured to tear along the longitudinal scoring <NUM> in order to peel-away when the hub <NUM> is broken and peeled away by pulling the wings 118a and <NUM>18b away from each other. The first hub portion <NUM> may include a second notch (e.g., <NUM> in <FIG>) opposite the first notch <NUM>. In such cases, the second notch is also fractured by pulling the wings 118a and 118b away from each other. The elongate sheath <NUM> may further include a second longitudinal scoring (not shown) at which the hub <NUM> may be broken and torn.

The first hub portion <NUM> and the second hub portion <NUM> may be comprised of material having different material properties. The first hub portion <NUM> may have different surface properties, durometer, ultimate or tensile strength, modulus of elasticity or other material properties than the second hub portion <NUM>. The second hub portion <NUM> may be more rigid, stiffer, tougher, or harder, relative to the first hub portion <NUM>. The different material properties of the first hub portion <NUM> relative to the second hub portion <NUM> allow the hub <NUM> to be increased in size to accommodate larger pumps and medical devices while still able to be efficiently broken by the medical personnel's hands. In an embodiment of the invention, the material forming the second hub portion <NUM> has an ultimate strength that is greater than an ultimate strength of the material forming the first hub portion <NUM>. In an example not according to the invention, the material forming the second hub portion <NUM> does not have an ultimate strength that is greater than an ultimate strength of the material forming the first hub portion <NUM>. In some implementations, the material forming the second hub portion <NUM> has a rigidity that is greater than a rigidity of the material forming the first hub portion <NUM>. In certain implementations, the first material forming the first hub portion <NUM> has a hardness of <NUM> Shore D. In some implementations, the first material may have a hardness of <NUM> Shore D, <NUM> Shore D, <NUM> Shore D, <NUM> Shore D, <NUM> Shore D, or any other suitable hardness. In some implementations, the second material forming the second hub portion <NUM> has a hardness of <NUM> Shore D, <NUM> Shore D, <NUM> Shore D, <NUM> Shore D, <NUM> Shore D, <NUM> Shore D, or any other suitable hardness.

<FIG> shows a perspective view of the first hub portion <NUM> of the introducer hub assembly <NUM> of <FIG>. The first hub portion <NUM> is attached to the elongate sheath <NUM> at a proximal end of the elongate sheath <NUM> and includes a first notch <NUM> defined by a first ridge128a and a second ridge 128b, and ridges <NUM>. The first notch <NUM> may be aligned with a longitudinal scoring <NUM> on the elongate sheath <NUM> parallel to the longitudinal axis <NUM> of the elongate sheath <NUM>. The first hub portion <NUM> may define the first notch <NUM> with a minimum thickness <NUM> of the first hub portion <NUM> at the first notch <NUM>. The first notch <NUM> may be further described by the first ridge 128a and the second ridge 128b. The ridges <NUM> may be constructed as ribbed features or grooves oriented in a direction or many directions on the first hub portion <NUM>. The ridges <NUM> allow the first hub portion <NUM> to more securely interface with an over-molded layer, promoting rigidity of the structure during breaking of the introducer hub assembly <NUM>. The ridges <NUM> provide a mechanical interlock between the first hub portion <NUM> and the second hub portion (e.g., <NUM> in <FIG>) to transmit torque applied to the wings (e.g., 118a and 118b in <FIG>) to the first hub portion <NUM>. The force applied to the wings (e.g., 118a and 118b in <FIG>) is thus transmitted to a break wall of the first notch <NUM>. The first hub portion <NUM> may form a hemostatic bond with the elongate sheath <NUM>, in particular if the first hub portion <NUM> and the elongate sheath <NUM> are both comprised of a same material.

<FIG> shows a perspective view of the introducer hub assembly <NUM> according to certain embodiments. The introducer hub assembly <NUM> includes an elongate sheath <NUM>, the first hub portion <NUM> having a first notch <NUM> and a second notch <NUM>, and the second hub portion <NUM> having two wings 118a and 118b. The first hub portion <NUM> has a proximal end portion <NUM> and a distal end portion <NUM>. The first hub portion <NUM> is connected to the elongate sheath <NUM> at the distal end portion <NUM>. The second hub portion <NUM> partially covers the first hub portion <NUM>. In some implementations, the second hub portion <NUM> covers the first hub portion <NUM> in near entirety except at an opening <NUM> above the first notch <NUM>. In some implementations, the second hub portion may cover a smaller portion of the first hub portion <NUM>. As described above, the first and second hub portions can be formed using various techniques (e.g., over-molding the second hub portion <NUM> onto the first hub portion <NUM> or molding the first and second hub portions <NUM>, <NUM> separately and then fixing them together using adhesives).

The first notch <NUM> is oriented parallel to a longitudinal axis <NUM> of the elongate sheath <NUM> and is in line with a longitudinal scoring <NUM> of the elongate sheath <NUM> such that the hub assembly <NUM> may function as a peel-away introducer upon breaking of the hub <NUM> at the first notch <NUM> and tearing of the elongate sheath <NUM> along the longitudinal scoring <NUM>. The hub <NUM> has a second notch <NUM> in the first hub portion <NUM> shown on an opposite side of the hub <NUM> as the first notch <NUM>. The second notch <NUM> further facilitates breaking of the hub <NUM> for removal of the hub assembly <NUM>. The second notch <NUM> may be defined in a similar way as the first notch <NUM> and may also be oriented to be parallel to the longitudinal axis <NUM> of the elongate sheath <NUM>. The longitudinal sheath <NUM> may include a second longitudinal scoring (not shown) which is aligned with the second notch <NUM> and is opposite the longitudinal scoring <NUM>.

During removal of the introducer assembly <NUM> a force is applied to the wings 118a and 118b pushing the wide faces 124a and 124b of the wings 118a and 118b toward each other. As the force is transferred through the material and applied toward the first notch <NUM>, there is a compressive force in the hub at the first notch <NUM> and a tension at the second notch <NUM> such that both the first notch <NUM> is broken. Application of a force to the wings in the opposite direction breaks the second notch <NUM>. The first notch <NUM> in the first hub portion <NUM> and the minimum thickness <NUM> of the first hub portion <NUM> at the first notch <NUM> and second notch <NUM> allows the hub <NUM> to be easily broken at the first notch <NUM> and second notch <NUM>. The first hub portion may comprise a material having a low ultimate strength to further facilitate the breaking of the hub <NUM> at the first notch <NUM> and the second notch <NUM>. In an embodiment of the invention, the second hub portion <NUM> comprises a material having a higher ultimate strength than the material of the first hub portion <NUM>. In an example not according to the invention, the second hub portion <NUM> does not comprise a material having a higher ultimate strength than the material of the first hub portion <NUM>. In some implementations, the first hub portion <NUM> and the second hub portion <NUM> may be comprised of polyether block amide (e.g., PEBAX® manufactured by Arkema Group) or similar material. The second hub portion <NUM> includes the wings 118a and 118b which are able to withstand the force required to break the hub <NUM> without flexing, facilitating breaking of the hub. Further, the second hub portion <NUM> may have an increased thickness <NUM> where it covers the first hub portion <NUM> in order to provide rigidity to the hub <NUM>.

<FIG> shows a perspective view of the first notch <NUM> in the introducer hub assembly <NUM> of <FIG> and <FIG>. The first notch <NUM> is formed in the first hub portion <NUM> having a minimum thickness <NUM> at the first notch <NUM>. The first notch <NUM> runs the length of the first hub portion <NUM> from the proximal end portion <NUM> to the distal end portion <NUM>. The first notch <NUM> is further defined by a first and second ridge 128a and 128b formed in the first hub portion <NUM>. The second hub portion <NUM> partially covers the first hub portion <NUM> and includes an opening <NUM> over the first notch <NUM>. The second hub portion <NUM> may have an associated thickness <NUM>. In some implementations the first hub portion <NUM> has a minimum thickness <NUM> of <NUM> at the first notch <NUM>. In some implementations, the first hub portion <NUM> has a maximum thickness of <NUM> at the first notch <NUM>. In certain implementations, the first hub portion <NUM> has a thickness <NUM> at the first notch <NUM> of <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or any other suitable thickness.

In some implementations, the first hub portion <NUM> has a variable thickness <NUM> at the first notch <NUM> along the length of the first notch <NUM>. In certain implementations, the first hub portion <NUM> has a greater thickness <NUM> at the proximal end portion <NUM> of the first hub portion <NUM> than at the distal end portion <NUM>. The distal end portion <NUM> of the notch <NUM> nearest the connection between the hub <NUM> and the elongate sheath <NUM> can have the maximum stress concentration during fracture and may therefore be the intended initiation point of the break. Thus, a relatively thin break wall of the notch <NUM> at the distal end portion <NUM> reduces the force required to start the break.

In some implementations, a hemostatic valve (not shown) is included in the hub <NUM><NUM> at the proximal end portion <NUM>. The proximal end portion <NUM> in which the valve is disposed must be strong enough to support the hoop stress induced in the hub <NUM> from compression of the valve. This is especially important when objects, such as catheters, are inserted through the hub, increasing the hoop stress. In some implementations, the thickness <NUM> of the notch <NUM> at the proximal end portion <NUM> is greater than the thickness of the notch <NUM> at the distal end portion <NUM>. The increased notch thickness at the proximal end portion <NUM> reinforces the hub <NUM> in the area of increased hoop stress. In some implementations, the thickness of the notch <NUM> at the distal end portion <NUM> is around <NUM>" - <NUM>". In some implementations, the thickness of the notch <NUM> at distal end portion <NUM> is <NUM>", <NUM>", <NUM>", <NUM>", <NUM>", <NUM>", <NUM>", <NUM>" or any other suitable thickness. In some implementations, the thickness of the notch <NUM> at the proximal end portion <NUM> of the first hub portion <NUM> is around <NUM>" - <NUM>". In some implementations, the thickness of the notch <NUM> at the proximal end portion <NUM> of the first hub portion <NUM> is <NUM>", <NUM>", <NUM>", <NUM><NUM>", <NUM>", <NUM>", <NUM>" or any other suitable thickness. In some implementations, the change in thickness may occur over a smooth transition. In some implementations, the change in thickness may occur via a series of steps of increased thickness.

The use of the softer material to form the first hub portion <NUM> allows the variation in the thickness of the notch <NUM> along its length. This is because the thickness of the notch <NUM> is constrained on the upper end by the maximum allowable break force and on the lower end by manufacturing tolerances. If the notch <NUM> is too thick, it cannot be broken. But if it is too thin, it cannot be easily manufactured by traditional processes (e.g., injection molding). The use of a softer material for the first hub portion <NUM> increases the upper limit for the notch thickness because it enables sufficiently low break force at greater notch thicknesses. This increase in the upper limit of the notch thickness affords a range within which the notch thickness can vary, thereby enabling variation in the notch thickness along the length of the notch. Thus, the use of a different material for the first hub portion <NUM> compared to the second hub portion <NUM> enables varying the thickness of the notch along the length of the notch.

<FIG> shows a perspective view along the longitudinal axis <NUM> of the elongate sheath <NUM> of an introducer hub assembly <NUM> according to certain embodiments. The introducer hub assembly <NUM> includes the elongate sheath <NUM> sized to fit a heart pump or medical device and to be inserted into a blood vessel of a patient. The elongate sheath <NUM> is surrounded by the first hub portion <NUM> including a first notch <NUM> at which point the thickness of the first hub portion <NUM> may be at a minimum thickness <NUM>. A second hub portion <NUM> surrounds the first hub portion <NUM> and includes an opening <NUM> over the first notch <NUM>. In some implementations, the first notch <NUM> may be further defined by a ridge or extension of the first hub portion <NUM> (shown as 128a and 128b in <FIG>). In some implementations, a base of the first notch <NUM> may be defined by the first hub portion <NUM> and the second hub portion <NUM> may further define an upper portion of the first notch <NUM>. The second hub portion <NUM> also includes a first wing 118a and a second wing <NUM>18b.

<FIG> shows a perspective view of an alternative embodiment of the introducer hub assembly <NUM> with wings 218a and 218b having a transverse orientation. The introducer hub assembly <NUM> includes an elongate sheath <NUM> having an inner diameter <NUM> sized to allow the passage of a heart pump into a blood vessel of a patient and a longitudinal axis <NUM>, a first hub portion <NUM> having a first notch <NUM>, and a second hub portion <NUM> having an opening <NUM> over the first notch <NUM> and first and second wings 218a and 218b.

The first wing 218a and the second wing 218b are oriented such that wide faces 224a and 224b of the wings 218a and 218b are normal to the longitudinal axis <NUM> of the elongate sheath <NUM>. In this embodiment, the introducer hub assembly <NUM> is fractured and separated from the patient using a different technique than for the embodiment of <FIG>. More specifically, to break the hub <NUM> at the first notch <NUM>, the wide faces 224a and 224b of the wings 218a and 218b are forced toward the elongate sheath <NUM>. The hub <NUM> fractures along the first notch <NUM> and along a second notch (not shown) opposite the first notch <NUM>. Additionally, the elongate sheath <NUM> tears at a longitudinal scoring <NUM> and at a second longitudinal scoring (not shown) which is opposite the longitudinal scoring <NUM>. The introducer hub assembly <NUM> is now broken in half and can be removed, leaving the device, catheter or guidewire in place in a blood vessel of a patient.

<FIG> shows the introducer hub assembly <NUM> of <FIG>, <FIG> and <FIG> inserted into a blood vessel of a patient <NUM> with a percutaneous pump <NUM> extending partially therethrough. The percutaneous pump <NUM> can include various features, such as a pump head <NUM> and a catheter body <NUM>. The percutaneous pump <NUM> may be an intravascular heart pump, a heart pump driven by a flexible shaft and a motor positioned external to the patient's body, a heart pump including an implantable motor, a heart pump having an expandable pump rotor, or any other suitable pump. The introducer hub assembly <NUM> is advanced into the blood vessel <NUM> through the blood vessel aperture <NUM> in the direction indicated by arrow <NUM> and then the percutaneous pump <NUM> is inserted through the introducer hub assembly <NUM> and into the blood vessel <NUM>. The blood vessel <NUM> may be a femoral artery, and the blood vessel aperture <NUM> may be an arteriotomy.

After the percutaneous pump <NUM> has been advanced through the introducer hub assembly <NUM> the introducer hub assembly <NUM> may be removed and in some implementations replaced by a device appropriate for longer-term use. To remove the introducer hub assembly, a healthcare professional may grasp the first and second wings 118a and 118b and apply a force to the wings 118a and 118b in a direction either toward the elongate sheath <NUM> or a direction radial to the elongate sheath <NUM> forcing a first wing 118a toward the second wing 118b depending on the orientations of the first and second wings 118a and 118b relative to the elongate sheath <NUM>. In the orientation of wings 118a and 118b shown, the healthcare professional applies a radial force (radial with respect to the elongate sheath <NUM>) to the wings 118a and 118b to move them toward each other. The first and second wings 118a and 118b are formed of a stiff material of the second hub portion <NUM> and do not flex when force is applied. The applied force is transmitted from the wings 118a and 118b to the first notch <NUM> and the second notch <NUM> (not shown). The minimum thickness <NUM> of the first hub portion <NUM> at the first notch <NUM> and second notch <NUM> allows the hub <NUM> to be broken at the first notch <NUM> and second notch <NUM>. In some implementations, the healthcare professional applies a second radial force in an opposite direction in order to break the second notch <NUM>. The longitudinal scoring <NUM> on the elongate sheath <NUM> allows the sheath to separate along the longitudinal axis <NUM>, and the hub <NUM> and elongate sheath <NUM> may be peeled away in two pieces leaving the percutaneous pump <NUM> in place in the blood vessel <NUM>.

The foregoing is merely illustrative of the principles of the disclosure, and the apparatuses can be practiced by other than the described embodiments, which are presented for purposes of illustration and not of limitation. It is to be understood that the apparatuses disclosed herein, while shown for use in percutaneous insertion of heart pumps, may be applied to apparatuses in other applications requiring hemostasis.

Claim 1:
An introducer assembly (<NUM>, <NUM>, <NUM>) comprising:
an elongate sheath (<NUM>, <NUM>, <NUM>) sized for insertion into a blood vessel of a patient, the sheath having a longitudinal axis (<NUM>, <NUM>, <NUM>);
a hub (<NUM>, <NUM>, <NUM>) coupled to a proximal portion of the elongate sheath (<NUM>, <NUM>, <NUM>), the hub (<NUM>, <NUM>, <NUM>) comprising:
a first hub portion (<NUM>, <NUM>, <NUM>) having a first notch (<NUM>, <NUM>, <NUM>);
a second hub portion (<NUM>, <NUM>, <NUM>) partially surrounding the first hub portion (<NUM>, <NUM>, <NUM>), the second hub portion (<NUM>, <NUM>, <NUM>) comprising:
two wings (18a, 18b, 118a, 118b, 218a, 218b); and
an opening (<NUM>, <NUM>, <NUM>) disposed above the first notch (<NUM>, <NUM>, <NUM>); and
wherein the first hub portion (<NUM>, <NUM>, <NUM>) comprises a first material and the second hub portion (<NUM>, <NUM>, <NUM>) comprises a second material, the first material differing from the second material,
characterized in that the first material has a first ultimate strength and the second material has a second ultimate strength, the second ultimate strength being greater than the first ultimate strength.