Patent Description:
Lately there has been a move toward the use of peripheral vessels to access the cardiovascular system in order to avoid traumatic open chest surgery. The move toward the use of peripheral vessels instead of central cardiovascular vessels has been accompanied by the development of a large number of specific devices and tools that are specifically designed for peripheral use. Vascular introducers are the most common devices that have been developed to allow peripheral vascular access. For providing access to a vessel, an introducer sheath usually is directly pierced into a vessel, in particular with the help of a dilator.

Once a medical device, such as a catheter, has been inserted through the introducer sheath into a patient's vessel, the introducer sheath usually is no longer needed and it is desired to remove it. However, since the medical device may be connected to a device external to the patient's body, such as a power source, the introducer sheath cannot be simply retracted but has to be peeled away from the medical device. Commonly, the introducer sheath is separated along its length in a longitudinal direction so that the resulting pieces can be removed from the patient. In order to assist in splitting the introducer sheath, handles may be provided that can be gripped by a user, for example a surgeon, to apply a breaking force. Examples for such introducer sheaths are disclosed in <CIT> and <CIT>. Usually, a hemostatic valve at the distal portion of the introducer sheath has to be broken, which requires a high initial force. This cumbersome procedure can cause difficulties and harm to the patient, for instance if the medical device is inadvertently retracted when the handles are actuated to apply the breaking force.

<CIT> discloses an introducer system including a reclosable, split sheath introducer. The sheath is a two-part sheath that can be assembled around an implanted lead body and advanced into an existing venous entry point over an implanted lead. The introducer may alternatively include a one-part sheath having curvilinear overlapping flaps that enclose the sheath lumen but may be parted to allow assembly of the introducer over an implanted lead. Handle parts are provided at the sheath parts to facilitate positioning of the sheath parts.

<CIT> discloses an introducer sheath having a flexible tube-shaped sheath body and a hub into which the base end of the sheath body is inserted. The hub takes up the base end of the sheath body into the hub by means of take-up shafts while tearing the base end of the sheath body by cutting blades, and thus the length of extension of the sheath body from the hub can be shortened.

It is an objective of the present invention to provide an introducer sheath for providing access to a patient's body that can be separated along its length, wherein handling is improved and in particular a breaking force that has to be applied by a user to split the introducer sheath is reduced.

The invention is described in the accompanying independent claim, with preferred embodiments being specified in the dependent claims.

According to the invention, an introducer sheath for providing access in a patient's body is provided, in particular transcutaneous access, more specifically vascular access. The introducer sheath comprises a tubular body with a distal portion and a proximal portion, the proximal portion being configured to be inserted into the patient's body, such as a vessel or other body cavity, to allow a medical device to be inserted through the introducer sheath into the patient's body. For instance, the medical device may be inserted into a patient's vessel and may be a catheter that may be connected to an axial blood pump. In other cases, the introducer sheath may be a cannula of a trocar. The introducer sheath is structured to facilitate separation along its length in a longitudinal direction. For example, at least the distal portion of the tubular body may comprise a structure, such as a longitudinal notch, forming a predetermined breaking line. It is to be understood that the term "proximal" refers to directions towards the heart, while the term "distal" refers to directions away from the heart.

The introducer sheath further comprises at least one handle which is pivotable about a fulcrum, the handle having a first end portion and a free second end portion so as to form a lever. Pivoting the handle about the fulcrum causes a contacting portion of the handle to act on a respective counter portion that is operatively connected to the distal portion of the tubular body, thereby creating a breaking force that causes the distal portion of the tubular body to break, split or crack. Due to the lever principle, the pivotable handle allows for a reduction of the force that has to be applied by a user to break the introducer sheath. Not only is the force reduced, the general handling during separation of the introducer sheath is also improved, in particular with respect to ergonomic aspects, for instance movement and position of the hands and arms of a user. This results from the fact that, in contrast to a handle that is fixedly and directly attached to the tubular body of the introducer sheath, a pivotable handle transmits the force applied by a user to the introducer sheath indirectly.

In an embodiment, the fulcrum is disposed eccentrically in the first end portion of the handle and the contacting portion is disposed at an edge of the first end portion, wherein a distance between the contacting portion and the fulcrum is less than a distance between the free second end portion of the handle and the fulcrum to utilize the lever principle. Preferably, a distance between the fulcrum and the contacting portion is larger than a distance between the fulcrum and a portion of the edge of the first end portion adjacent the contacting portion. The edge of the first end portion of the handle may be specifically shaped, for example curved. In other words, pivoting the handle moves the contacting portion of the handle towards the counter portion and pushes away the counter portion when pivoting, i.e. in particular pushing or pulling, of the handle is continued. The contacting portion may already contact the counter portion in a neutral position, i.e. in an unstressed condition, or may come into contact only when the handle is pivoted. Due to the shape of the contact portion, the counter portion is pushed away until the distal portion of the introducer sheath breaks.

In an alternative embodiment, the fulcrum is disposed between the first and second end portions and the contacting portion is disposed at an edge of the first end portion. In another alternative embodiment, the contacting portion is disposed between the first and second end portions and the fulcrum is disposed in the first end portion.

Generally, it is sufficient if only a single handle is provided to create the breaking force. However, handling may be improved if another handle is provided. Thus, the introducer sheath may comprise at least one further handle, wherein - if two handles are provided - the two handles are preferably diametrically opposed with respect to the tubular body. The further handle may be fixedly attached to the distal portion of the tubular body, or both handles may be pivotably attached to the distal portion of the tubular body. Possibly, more than two handles, for example three or four handles, may be provided that can be arranged symmetrically about the tubular body of the introducer sheath. It will be appreciated that an asymmetrical arrangement is possible, too. It shall be understood that all features described for a single handle or one of the handles may also apply to the further handle or all handles in embodiments where two or more handles are provided.

The counter portion may be disposed on and particularly be part of the distal portion of the introducer sheath. Alternatively, in embodiments having two handles, the counter portion associated with one of the handles may be the contacting portion of the other one of the handles and preferably vice versa. In other words, the contacting portions of the two handles may act on each other such that a breaking force is applied to the distal portion of the introducer sheath.

The handle or handles may be pivotably attached to the distal portion of the tubular body via a hinge, wherein the hinge preferably comprises at least one pin arranged along the fulcrum and at least one cavity that receives the pin. It will be appreciated that the handles may be pivotably attached to the tubular body of the introducer sheath in other ways.

The handle, in an unstressed condition, i.e. in a neutral condition without application of an external force, may extend from the distal portion of the tubular body of the introducer sheath at different angles. In case two handles are provided, the handles may extend from the introducer sheath symmetrically, i.e. at same angles. However, the two handles may also extend at different angles. The handle may extend from the introducer sheath at an angle between <NUM>° and <NUM>° or at an angle less than <NUM>°. Preferably, the angle ranges between <NUM>° and <NUM>° or between <NUM>° and <NUM>°. In case the angle is unequal to <NUM>°, the handle may point towards either the distal end or the proximal end of the body of the introducer sheath.

The handle may be either pushed or pulled by a user. In other words, the handle may be pivotably attached to the distal portion of the tubular body such that pivoting in a direction towards or away from the proximal portion of the tubular body causes the distal portion to break. Pushing the handle, that is to say, pivoting the handle towards the proximal end portion, may be advantageous because pulling the handle could lead to an inadvertent retraction of the introducer sheath from the patient's vessel, which might cause problems because the introducer sheath cannot be pushed back into the vessel.

In a preferred embodiment, the handle or handles may be secured or locked to prevent inadvertent actuation. For this purpose, the handle may comprise an engagement portion configured to engage a locking member such that the handle is prevented from pivoting. The locking member may be provided separately or may be comprised in the introducer sheath, wherein the locking member can be manipulated to be in or out of engagement with the engagement portion of the handle. The locking member may be engageable with the engagement portion of the handle by means of threads, a hook, a clip or any other appropriate engagement means. The locking member may be a locking cap. For example, the locking member may be rotated to secure or release the handle. It will be appreciated that the locking member may also be part of a dilator that is inserted into the introducer sheath.

According to the invention, the introducer sheath comprises a hemostatic valve in the distal portion of the tubular body. The hemostatic valve provides hemostasis. In other words, it seals the distal end of the introducer sheath to prevent blood from flowing through the valve during insertion of a medical device, such as a catheter. The valve may include a membrane that may be constructed as a flexible disk or in another configuration providing the function of a check valve. The at least one handle preferably is attached to the hemostatic valve such that the breaking force can be applied directly to the valve so as to split the valve. Splitting the valve usually requires the highest force during separation of the introducer sheath.

The foregoing summary, as well as the following detailed description of preferred embodiments, are better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, reference is made to the drawings. The scope of the disclosure is not limited, however, to the specific embodiments disclosed in the drawings. In the drawings:.

Referring to <FIG>, an introducer sheath <NUM> according to an embodiment is shown assembled on a dilator <NUM>. A tapered tip <NUM> of the dilator <NUM> extends proximally of the introducer sheath <NUM>. A distal end portion <NUM> of the dilator can be gripped to manipulate the assembly and may include a port <NUM> for example for a guide wire. The dilator and introducer sheath assembly can be inserted into a patient's vessel that has been accessed for example by means of the Seldinger technique. In other embodiments, the assembly could be a trocar having a cannula and an obturator for providing access to other body cavities. The introducer sheath <NUM> has a tubular body <NUM> with the distal portion <NUM> and a proximal portion <NUM>. A hemostatic valve <NUM> is arranged in the distal portion <NUM> of the tubular body <NUM> to provide hemostasis, i.e. to prevent blood from flowing out of the introducer sheath <NUM> when inserted in a patient's vessel. In one embodiment the hemostasis valve may be made of two or more separate pieces that, when assembled inside a hemostasis shell, will create a fluidic tight seal preventing blood from flowing back. The hemostasis valve may be a "silicone gland".

Once a medical device, such as a catheter, has been inserted through the introducer sheath <NUM> after retraction of the dilator <NUM>, it is desired to remove the introducer sheath <NUM> from the patient. Due to the presence of the medical device, however, the introducer sheath <NUM> cannot be retracted but has to be separated and peeled away from the medical device. While the tubular body <NUM> of the introducer sheath <NUM> can be torn along its length with a relatively low force, the hemostasis valve <NUM> has to be cracked with a relatively high force. In order to allow splitting of the hemostasis valve <NUM>, the valve <NUM> is provided with longitudinal notches <NUM> (only one being visible in <FIG>; a single notch may also be possible) on opposing sides of the hemostasis valve <NUM>, forming predetermined breaking lines. Handles <NUM> and <NUM> are provided to apply a breaking force to the hemostasis valve <NUM> to initiate splitting of the valve <NUM>. A locking cap or safety cap <NUM> is provided to prevent the handles <NUM> and <NUM> from inadvertent actuation, as described in more detail below. While it is preferred in this embodiment that both handles <NUM>, <NUM> are pivotable, one of the handles may be fixed, or even only a single handle may be provided.

<FIG> show a side view of the distal portion <NUM> of the introducer sheath <NUM> of <FIG> including the hemostasis valve <NUM>, the handles <NUM> and <NUM> and the locking cap <NUM>. The handles <NUM> and <NUM> have respective first end portions <NUM> and <NUM> and free second end portions <NUM> and <NUM>. They extend from the hemostasis valve <NUM> at an angle of about <NUM>° and point away from the proximal portion <NUM> of the body <NUM> of the introducer sheath <NUM>. The handles <NUM> and <NUM> are pivotably attached to the hemostasis valve <NUM>, for example by means of a hinge, as described in more detail below with respect to <FIG>. The handles <NUM> and <NUM> each form a lever and are pivotable about a fulcrum <NUM> and <NUM>, respectively, in particular pivotable towards the proximal portion <NUM> of the body <NUM> of the introducer sheath <NUM> as indicated by the arrows in <FIG>.

The handles <NUM> and <NUM> have an engagement portion <NUM>, such as a hook, that is engageable with the locking cap <NUM>. For instance, the locking cap <NUM> may have inner threads that engage the hooks <NUM> or may engage the hooks like a bayonet coupling. The locking cap <NUM> particularly prevents inadvertent actuation of the handles <NUM> and <NUM> during insertion of the introducer sheath <NUM> when assembled on a dilator <NUM> as shown in <FIG>. During this stage of the procedure the handles <NUM> and <NUM> may be used to assist in insertion of the assembly and it would not be desirable but harmful to split the hemostasis valve <NUM> at this point of time.

When the surgeon decides to remove the introducer sheath <NUM> from the patient, the introducer sheath <NUM> has to be separated into two pieces and peeled away from a medical device that has been inserted through the introducer sheath <NUM>. The surgeon may then release the locking cap <NUM> such that the handles <NUM> and <NUM> are operable. In this embodiment, the handles <NUM> and <NUM> can be pushed down to the proximal portion <NUM> of the tubular body <NUM> of the introducer sheath <NUM>. The actuated position is shown in <FIG>. The handles <NUM> and <NUM> are pivoted about the respective fulcrum <NUM> and <NUM> such that the contact portions <NUM> and <NUM> act on each other to cause a breaking force that cracks the hemostasis valve <NUM>. The location where the contacting portions <NUM> and <NUM> act on each other is indicated at reference number <NUM> in <FIG>. In this embodiment, the contacting portions <NUM> and <NUM> function as respective counter portions. The contacting portion <NUM> of the handle <NUM> functions as the counter portion for the contacting portion <NUM> of the handle <NUM>, while the contacting portion <NUM> of the handle <NUM> functions as the counter portion for the contacting portion <NUM> of the handle <NUM>. Because of the eccentric positions of the fulcrums <NUM> and <NUM> in the end portions <NUM> and <NUM> of the handles <NUM> and <NUM> and the specifically shaped edges of the end portions <NUM> and <NUM>, the contacting portions <NUM> and <NUM> are forced away from each other as the handles <NUM> and <NUM> are pivoted to create a breaking force that cracks the hemostasis valve <NUM> along the notch <NUM>. Due to the lever principle the force that has to be applied by the surgeon to create the breaking force is reduced. The pivotable handles facilitate handling compared to fixedly attached handles.

<FIG> show another embodiment of the handles <NUM>' and <NUM>' which is similar to the above-described embodiment with the exception that the handles <NUM>' and <NUM>' are pivotable away from the proximal portion <NUM> of the body <NUM> of the introducer sheath <NUM> to create the breaking force. As shown in <FIG>, the initial position is substantially the same as in the embodiment of <FIG>. However, <FIG> shows that the handles <NUM>' and <NUM>' are pivoted about the fulcrums <NUM>' and <NUM>' in the opposite direction compared to the embodiment of <FIG> and act on each other at point <NUM>' to create the breaking force that cracks the hemostasis valve <NUM> along the notch <NUM>.

Another embodiment is shown in <FIG> which is similar to the above-described embodiments. As in the embodiment of <FIG>, the handles <NUM>" and <NUM>" are pivotable about respective fulcrums <NUM>" and <NUM>" towards the proximal portion <NUM> of the body <NUM> of the introducer sheath <NUM> to create a breaking force that cracks the hemostasis valve <NUM>. However, in an unstressed condition the handles <NUM>" and <NUM>" extend from the hemostasis valve <NUM> at a different angle compared to the other embodiments, namely a smaller angle where the handles <NUM>" and <NUM>" are closer to the tubular body <NUM>. In this "low-profile configuration" the handles <NUM>" and <NUM>" only have to be pressed together to crack the hemostasis valve <NUM>. In this embodiment, the handles <NUM>" and <NUM>" are moved only by a short distance compared to the other embodiments. This, however, is sufficient to at least initially split the hemostasis valve <NUM>, and may be advantageous because the risk of retracting the introducer sheath <NUM> can be reduced. The surgeon can complete separation of the introducer sheath <NUM> by manually tearing and peeling away the introducer sheath <NUM> from an inserted medical device.

<FIG> shows another embodiment of an introducer sheath <NUM>' which is similar to the embodiment of <FIG>. The only difference is the shape of the engagement portion <NUM>' that can be engaged by the locking cap <NUM> (not shown) to secure the handles <NUM> and <NUM> and prevent them from pivoting. In the embodiment of <FIG>, the engagement portions <NUM>' have a semicircular shape and are formed as pieces separate from the handles <NUM> and <NUM>, for instance injection molded pieces. In the embodiment of the introducer sheath <NUM>" shown in <FIG>, the engagement portions <NUM>" are formed integrally with the handles <NUM> and <NUM>.

<FIG> show details of the hinge connection between the handles <NUM> and <NUM> and the hemostasis valve <NUM>. Generally, the hinge comprises a pin <NUM> that is rotatably received in a cavity <NUM> to allow the handles <NUM> and <NUM> to be pivoted about the fulcrums <NUM> and <NUM>, respectively. The hinge further comprises a base portion <NUM> that has an elongated shape and supports the pin <NUM>. As shown in <FIG>, the base portions <NUM> prevent the handles <NUM> and <NUM> from falling off the hemostasis valve <NUM>. Slots <NUM> are provided to access the cavities <NUM>. The slots <NUM> have a width corresponding to the width of the base portions <NUM> to allow the base portions <NUM> to be inserted into the slots <NUM> only in a certain orientation in which the elongate base portions <NUM> are aligned with the slots <NUM>.

Another embodiment of an introducer sheath <NUM> is shown in <FIG>, <FIG>. The introducer sheath <NUM> has a tubular body <NUM> and a hemostasis valve <NUM> disposed at the distal portion <NUM> of the body <NUM>. Handles <NUM> and <NUM> are pivotably attached to the hemostasis valve <NUM> to aid in splitting the hemostasis valve <NUM>. In contrast to the previously described embodiments, the handles <NUM> and <NUM> do not contact each other and do not act on each other to create a breaking force. Instead, the handles <NUM> and <NUM> are pivotably attached to a fixed frame portion <NUM> by means of hinges that form respective fulcrums <NUM> and <NUM>. In this embodiment, the fulcrums <NUM> and <NUM> are disposed between first end portions <NUM> and <NUM> and second end portions <NUM> and <NUM> of the handles <NUM> and <NUM>, respectively. The first end portions <NUM> and <NUM> are bent, with contact portions <NUM> and <NUM> contacting respective counter portions <NUM> and <NUM> that are disposed in the hemostasis valve <NUM>. Pulling the handles <NUM> and <NUM> in a direction away from the proximal portion <NUM> of the body <NUM> of the introducer sheath <NUM> creates a force that pushes the respective counter portions <NUM> and <NUM> away from the frame portion <NUM> to crack the hemostasis valve <NUM>. In this embodiment, both handles <NUM> and <NUM> act independently.

An example of an introducer sheath <NUM> having a tubular body <NUM> and a hemostasis valve <NUM> that can be separated by means of handles <NUM> and <NUM> is disclosed in <FIG>. In this embodiment, the handles <NUM> and <NUM> are used to apply a torsional force to crack the hemostasis valve <NUM>, as indicated by the arrows in <FIG>. Longitudinal notches <NUM> and <NUM> facilitate splitting of the hemostasis valve into two pieces. As becomes apparent from <FIG>, the handles extend from the hemostasis valve at an angle of <NUM>° and are designed asymmetrically in top view to facilitate handling, in particular to provide a space between the patient's body and the handles <NUM> and <NUM> for gripping the handles <NUM> and <NUM>.

<FIG> disclose another example of an introducer sheath <NUM> having a tubular body <NUM> and a hemostasis valve <NUM> that can be separated by means of handles <NUM> and <NUM>. Each of the handles <NUM> and <NUM> has wings 75a, 75b and 76a, 76b, respectively. In order to apply a breaking force to the hemostasis valve <NUM> a user grips the handles <NUM> and <NUM> and twists them in opposite directions, as indicated by the arrows in <FIG>. Twisting of the handles <NUM> and <NUM> is facilitated by providing each handle with two wings, wherein the handles <NUM> and <NUM> are twisted about an axis of rotation that runs perpendicular to the longitudinal axis of the tubular body <NUM> and between the wings 75a and 75b, and 76a and 76b, respectively. For instance, referring to <FIG>, wing 75a may be moved "downwards", while wing 75b is moved "upwards", whereas at the same time wing 76a is moved "upwards" and wing 76b is moved "downwards" to create a twisting movement. After an initial breaking force has been applied, the user pulls at the handles <NUM> and <NUM> further to completely separate the introducer sheath <NUM> into two pieces.

Claim 1:
An introducer sheath (<NUM>) for providing access in a patient's body, comprising a tubular body (<NUM>) with a distal portion (<NUM>) and a proximal portion (<NUM>), the proximal portion (<NUM>) being configured to be inserted into the patient's body to allow a medical device (<NUM>) to be inserted through the introducer sheath (<NUM>) into the patient's body, the introducer sheath (<NUM>) being structured to facilitate separation along its length in a longitudinal direction,
wherein the introducer sheath (<NUM>) further comprises a hemostatic valve (<NUM>) in the distal portion (<NUM>) of the tubular body (<NUM>) and at least a first handle (<NUM>) which is pivotable about a fulcrum (<NUM>),
wherein the first handle (<NUM>) has a first end portion (<NUM>) and a free second end portion (<NUM>) so as to form a lever, such that pivoting the handle (<NUM>) about the fulcrum (<NUM>) causes a contacting portion (<NUM>) of the handle to act on a respective counter portion (<NUM>) that is operatively connected to the distal portion (<NUM>) of the tubular body (<NUM>), thereby creating a breaking force that causes the hemostatic valve (<NUM>) and the distal portion (<NUM>) of the tubular body (<NUM>) to break.