Patent Description:
A variety of cardiovascular procedures, such as electrophysiology (EP) mapping and ablation, delivery and implantation of implantable cardioverter defibrillator (ICD) leads, percutaneous transluminal coronary angiography (PTCA), angioplasty, and the like, require vascular access for corresponding interventional medical devices (e.g., EP catheters, ICD leads, PTCA balloon catheters, etc.). Several techniques for introducing such devices into a patient's vasculature, such as the cut-down method and the Seldinger technique, are known.

The Seldinger technique involves surgically opening a vasculature of a patient with a relatively small incision and a needle, followed by inserting a guidewire into the vein or artery through the lumen of the needle. After removing the needle, a cylindrical dilator associated with a cylindrical introducer is inserted over the directing guidewire, followed by the advancement of the introducer along the directing dilator or guidewire into the vasculature until the distal end of the introducer sheath reaches the targeted location of the vasculature or anatomical structure (e.g., the heart) for an intended medical procedure. After removing the guidewire and dilator, the central lumen of the introducer sheath will establish a safe cardiovascular passageway of access to the blood vessel or anatomical structure, thus allowing for repetitive insertion and withdrawal of various interventional medical devices into and from the patient's vasculature, respectively.

To minimize blood loss or leakage from the distal opening of an introducer sheath, and to reduce the risk of air embolism during and after the Seldinger process, such an introducer sheath can be fit with a hemostasis valve system at the front of the proximal opening of the introducer sheath. The hemostasis valve system typically includes one or more valve gaskets contained within an introducer housing, also referred to as a cannula. For example, valve gaskets are disclosed in <CIT>, <CIT>, <CIT> and <CIT>. <CIT> describes a vascular sheath device and a matching structure of the vascular sheath and a pre-expander, the blood vessel sheath device comprises a shell, a hemostatic valve and an expansion tube, the expansion tube comprises at least one deformation part, and the deformation part is distributed in an S-shaped bending mode from the first end to the second end in the circumferential direction of the expansion tube, so that deformation part does not deform when not subjected to radial expansion force of the expansion tube. <CIT> describes valves for intravenous (IV) catheter assemblies for controlling fluidic flow. A thinner area of the valve around a slit is provided. <CIT> describes a self-sealing catheter valve that includes a flexible tubular part having a distal opening and an opposite proximal opening, and a proximal valve part. The proximal valve part has a curved self-sealing flexible diaphragm disposed inside the flexible tubular part and has a base perimeter united with a circumferential wall of the flexible tubular part. The curved self-sealing flexible diaphragm has a concave surface facing towards the proximal opening, and a convex surface facing towards the distal opening, and a flexible diaphragm wall of the curved self-sealing flexible diaphragm has a traverse slit. <CIT> describes a hemostasis valve assembly adapted for use within a catheter introducer. The valve assembly includes first, second and third sealing members wherein the second sealing member comprises a guide wire seal. The guide wire seal includes a plurality of lip members defining a pair of perpendicularly disposed slits and an aperture intersecting at least one of the slits. Two pairs of diametrically opposed pre-load ribs extend radially towards the aperture for pressing the lip members together in sealing engagement.

Disclosed herein is a valve gasket, including: an annular wall; a plurality of ligaments attached to and extending radially inward from the annular wall, wherein each ligament of the plurality of ligaments includes a ligament slit that divides the ligament into two ligament segments; and a membrane surrounded by the annular wall and attached to the plurality of ligaments and to the annular wall, wherein the membrane includes at least one membrane slit that divides the membrane into a plurality of flaps, wherein the plurality of ligaments are positioned with the plurality of ligament slits aligned with the at least one membrane slit, such that each flap is bounded along a circumferential edge by the annular wall, along a first radial edge by a first ligament segment, and along a second radial edge by a second ligament segment.

The valve gasket may also include a central protrusion positioned on the membrane, wherein the plurality of ligaments connect to the central protrusion. The central protrusion also includes a plurality of central protrusion slits that are aligned with the plurality of ligament slits, and thus the at least one membrane slit. In some embodiments of the disclosure, the central protrusion includes a guiding recess to facilitate insertion of an interventional medical device through the membrane.

According to aspects of the disclosure, the annular wall includes: a cylindrical portion; a beveled portion; a plurality of positioning protrusions extending axially from an exit surface of the cylindrical portion; and a plurality of positioning recesses extending radially into a circumferential surface of the beveled portion.

It is contemplated for the plurality of positioning recesses to be complementary to the plurality of positioning protrusions.

It is also contemplated for the plurality of positioning recesses to be aligned with the at least one membrane slit.

Still further, it is contemplated for the plurality of positioning protrusions to be alternately disposed with the plurality of positioning recesses around a circumference of the annular wall.

The at least one membrane slit may include any number of slits that divide the membrane into any number of flaps. For instance, in certain embodiments of the disclosure, the at least one membrane slit is a single membrane slit that divides the membrane into two symmetrical flaps, while in an alternative embodiment of the disclosure, the at least one membrane slit includes three membrane slits that divide the membrane into three congruent flaps.

Each ligament slit can form an angle between <NUM> degrees and <NUM> degrees with the membrane.

Also disclosed herein is a hemostasis valve, including a first valve gasket and a second valve gasket. The first valve gasket includes: an annular wall; a plurality of ligaments attached to and extending radially inward from the annular wall, wherein each ligament of the plurality of ligaments includes a ligament slit that divides the ligament into two ligament segments; and a membrane surrounded by the annular wall and attached to the plurality of ligaments and to the annular wall, wherein the membrane includes at least one membrane slit that divides the membrane into a plurality of flaps, wherein the plurality of ligaments are positioned with the plurality of ligament slits aligned with the at least one membrane slit, such that each flap is bounded along a circumferential edge by the annular wall, along a first radial edge by a first ligament segment, and along a second radial edge by a second ligament segment. The second valve gasket likewise includes: an annular wall; a plurality of ligaments attached to and extending radially inward from the annular wall, wherein each ligament of the plurality of ligaments includes a ligament slit that divides the ligament into two ligament segments; and a membrane surrounded by the annular wall and attached to the plurality of ligaments and to the annular wall, wherein the membrane includes at least one membrane slit that divides the membrane into a plurality of flaps, wherein the plurality of ligaments are positioned with the plurality of ligament slits aligned with the at least one membrane slit, such that each flap is bounded along a circumferential edge by the annular wall, along a first radial edge by a first ligament segment, and along a second radial edge by a second ligament segment. A rear surface of the first valve gasket is placed against a rear surface of the second valve gasket with the membrane of the first valve gasket pressed against the membrane of the second valve gasket.

The first valve gasket of the hemostasis valve may further include a central protrusion positioned on the membrane of the first valve gasket, wherein the plurality of ligaments of the first valve gasket connect to the central protrusion of the first valve gasket. The second valve gasket of the hemostasis valve may similarly include a central protrusion positioned on the membrane of the second valve gasket, wherein the plurality of ligaments of the second valve gasket connect to the central protrusion of the second valve gasket. At least one of the central protrusion of the first valve gasket and the central protrusion of the second valve gasket can include a guiding recess.

According to aspects of the disclosure, the annular wall of the first valve gasket includes: a cylindrical portion; a beveled portion; a plurality of positioning protrusions extending from an exit surface of the cylindrical portion; and a plurality of positioning recesses extending radially into the beveled portion. The annular wall of the second valve gasket can likewise include: a cylindrical portion; a beveled portion; a plurality of positioning protrusions extending from an exit surface of the cylindrical portion; and a plurality of positioning recesses extending radially into the beveled portion. Within the hemostasis valve, the first valve gasket is placed against the second valve gasket such that the positioning protrusions of the annular wall of the first valve gasket fit within the positioning recesses of the annular wall of the second valve gasket and the positioning protrusions of the annular wall of the second valve gasket fit within the positioning recesses of the annular wall of the first valve gasket. To facilitate such assembly, the positioning protrusions of the annular wall of the first valve gasket can be complementary to the positioning recesses of the annular wall of the second valve gasket, and the positioning protrusions of the annular wall of the second valve gasket can be complementary to the positioning recesses of the annular wall of the first valve gasket.

To improve sealing characteristics of the hemostasis valve, it is further contemplated that the positioning recesses of the first valve gasket can be aligned with the at least one membrane slit of the first valve gasket, and the positioning recesses of the second valve gasket can be aligned with the at least one membrane slit of the second valve gasket, such that, when the rear surface of the first valve gasket is placed against the rear surface of the second valve gasket, the at least one membrane slit of the first valve gasket is rotationally offset from the at least one membrane slit of the second valve gasket.

The first and second valve gaskets may be disposed within a rigid valve housing.

The first valve gasket can be structurally identical to the second valve gasket.

The instant disclosure also provides a valve gasket, including an annular wall and a sealing assembly disposed within the annular wall, wherein the sealing assembly includes: a central protrusion; a plurality of ligaments connected to the central protrusion, wherein each ligament of the plurality of ligaments extends radially away from the central protrusion towards the annular wall and is connected to the annular wall; a membrane connected to the central protrusion, to the plurality of ligaments, and to the annular wall; and at least one slit through the membrane, the central protrusion, and the plurality of ligaments, wherein the at least one slit separates the sealing assembly into a plurality of flaps, wherein each flap of the plurality of flaps is bounded on an outer circumferential edge by the annular wall, on an inner circumferential edge by the central protrusion, on a first radial edge by a first ligament of the plurality of ligaments, and on a second radial edge by a second ligament of the plurality of ligaments.

The central protrusion can include a guiding recess.

The valve gasket can also include a plurality of spaced-apart positioning protrusions extending axially from a first (e.g., cylindrical) portion of the annular wall and a plurality of positioning recesses set into a circumferential surface of a second (e.g., beveled) portion of the annular wall, wherein the plurality of positioning protrusions are alternately disposed with the plurality of positioning recesses around a circumference of the annular wall.

The foregoing and other aspects, features, details, utilities, and advantages of the present invention will be apparent from reading the following description and claims, and from reviewing the accompanying drawings.

While multiple embodiments are disclosed, still other embodiments of the present disclosure will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments.

The instant disclosure provides various valve gaskets as well as hemostasis valve systems and cardiovascular introducers with cannula units incorporating the same. For purposes of illustration, aspects of the disclosure will be described with reference to the introduction of an interventional medical device into a patient's vasculature. Those of ordinary skill in the art, however, will appreciate that the instant teachings may be applied to good advantage in other contexts.

<FIG> depicts the introduction of various medical devices, including guidewire <NUM>, cardiovascular introducer <NUM>, and dilator <NUM>, into a blood vessel <NUM> using the Seldinger technique. Insofar as the ordinarily skilled artisan will be familiar with the Seldinger technique, it need not be described in further detail herein.

As <FIG> illustrates, cardiovascular introducer <NUM> includes an introducer sheath <NUM>, a cannula unit <NUM>, a hemostasis valve system <NUM>, and a side-port fluid tubing <NUM> with an associated stopcock assembly <NUM>. As shown in <FIG>, cannula unit <NUM> is comprised of a cap <NUM> and a housing <NUM> circumferentially sealed together, within which integral hemostasis valve system <NUM> (e.g., a fully assembled unit of two valve gaskets 30a and 30b as described herein), is disposed at its proximal end. Side-port fluid tubing <NUM> and associated stopcock assembly <NUM> are also coupled to cannula unit <NUM> or housing <NUM> to enable the introduction of medical fluids (e.g., saline) through introducer <NUM> or introducer sheath <NUM> for an intended clinical procedure.

<FIG> is a cross-sectional view of cardiovascular introducer <NUM> incorporating an integral hemostasis valve system <NUM> within a circumferentially sealed cannula unit <NUM>. Various details of cannula unit <NUM>, including housing <NUM> and cap <NUM>, will be familiar to those of ordinary skill in the art; thus, cannula unit <NUM> will only be described herein to the extent necessary to understand the instant disclosure.

The exterior of cannula unit <NUM> is defined by a housing <NUM> and a cap <NUM>. Contained within circumferentially sealed housing <NUM> by cap <NUM> are a first (or proximal) valve gasket 30a and a second (or distal) valve gasket 30b, the structures and arrangements of which are described in greater detail below. As fully assembled and constrained within housing <NUM>, first and second valve gaskets 30a, 30b collectively constitute a hemostasis valve system <NUM>.

In embodiments of the disclosure, first and second valve gaskets 30a, 30b are structurally identical to each other and are oriented back-to-back within housing <NUM>. Accordingly, it should be understood that the descriptions of various valve gasket embodiments herein are equally applicable to either, or both, of valve gaskets 30a, 30b.

Each of valve gaskets 30a, 30b has two axial faces, one facing proximally and one facing distally. For convenience and ease of reference, the first (e.g., proximally-facing) axial face of a valve gasket will be referred to herein as the "entry face," while the second (e.g., distally-facing) axial face of a valve gasket will be referred to herein as the "exit face. " This same naming convention will be utilized to refer to the various surfaces of the valve gasket embodiments described herein (that is, proximally-facing surfaces will be referred to as "entry faces," while distally-facing surfaces will be referred to as "exit faces"). It will become apparent to those of ordinary skill in the art from reviewing this disclosure, however, that this naming convention follows from the orientation of first valve gasket 30a, and would be reversed when referring to second valve gasket 30b, the orientation of which is reversed relative to first valve gasket 30a as mentioned above and described in greater detail below.

<FIG> are various views of a valve gasket <NUM> according to a first embodiment disclosed herein. For reasons that will be clear upon reviewing the following disclosure, the embodiment of <FIG> can be referred to as a "biomimetic bicuspid valve gasket" (or simply a "bicuspid valve gasket"). <FIG> are perspective views of bicuspid valve gasket <NUM>, with <FIG> emphasizing the entry face of bicuspid valve gasket <NUM> and <FIG> emphasizing the exit face of bicuspid valve gasket <NUM>. <FIG> is a planar view looking towards the entry face of bicuspid valve gasket <NUM>. <FIG> is a planar view looking towards the exit face of bicuspid valve gasket <NUM>. <FIG> is a cross-sectional view taken along line E-E in <FIG>.

Bicuspid valve gasket <NUM> includes an annular wall <NUM>, a central protrusion <NUM>, a plurality of ligaments <NUM>, and a disc-shaped valve membrane <NUM>. Ligaments <NUM> extend radially from central protrusion <NUM> to annular wall <NUM>, and are attached to both. Likewise, valve membrane <NUM> is attached to annular wall <NUM>, central protrusion <NUM>, and ligaments <NUM>. In some embodiments of the disclosure, bicuspid valve gasket <NUM> may be formed as a unitary assembly, such as by reactive injection molding, or reactive compression molding, with use of a liquid or gum-like silicone rubber material. And, although all elements may be integrally formed, the term "sealing assembly" will be used herein as a shorthand to refer collectively to valve membrane <NUM>, central protrusion <NUM>, and ligaments <NUM>.

Central protrusion <NUM> is centrally located within annular wall <NUM> and protrudes from the entry face of valve membrane <NUM>. That is, central protrusion <NUM> is positioned on valve membrane <NUM> and has an axial centerline that is substantially coincident with the axial centerline of the annulus defined by annular wall <NUM>. Central protrusion <NUM> may be cylindrical, hemispherical, or any other shape suitable to the interconnection of ligaments <NUM> as described below (e.g., a square-shaped central protrusion could be used in a four-ligament configuration).

To aid in the insertion of an interventional medical device (e.g., guidewire <NUM> and/or dilator <NUM>) through a hemostasis valve system <NUM>, central protrusion <NUM> can include a guiding recess <NUM>, which can be formed in the nature of a depression into the entry face of central protrusion <NUM>. Guiding recess <NUM> may be conical, cylindrical, or any other suitable shape to help guide an interventional medical device towards the center of bicuspid valve gasket <NUM> during insertion. For instance, guiding recess <NUM> may have walls that slope conically inward, such that they are highest along the perimeter of guiding recess <NUM> and lowest near the center point of the annulus defined by annular wall <NUM>.

As mentioned above, each ligament <NUM> is geometrically connected to both central protrusion <NUM> and annular wall <NUM> and extends generally along a radius of the annulus defined by annular wall <NUM> on the entry face of valve membrane <NUM> (e.g., in the nature of a wheel spoke). Each ligament <NUM> extends above the entry face of membrane <NUM> to an upper surface <NUM>. Upper surface <NUM> may be parallel or inclined to the entry face of valve membrane <NUM>; where upper surface <NUM> is inclined relative to the entry face of valve membrane <NUM>, it is contemplated that the highest point of upper surface <NUM> will be where it meets annular wall <NUM> and that the lowest point of upper surface <NUM> will be where it meets central protrusion <NUM> (e.g., upper surface <NUM> of ligament <NUM> slopes downward towards central protrusion <NUM>). This latter configuration is shown to good advantage in <FIG>.

As also mentioned above, valve membrane <NUM> is geometrically attached to annular wall <NUM>, to central protrusion <NUM>, and to each ligament <NUM>. As explained in further detail below, these attachments support valve membrane <NUM>, bias valve membrane <NUM> into a closed position (e.g., to prevent fluid leakage through bicuspid valve gasket <NUM>), permit resilient, radial compression, or opening, under insertion forces imposed on the entry face (e.g., as an interventional medical device is inserted), and resist axial distension of valve membrane <NUM> under pressure (e.g., blood pressure) imposed on the exit face.

At least one slit <NUM> is formed through valve membrane <NUM>. In the case of bicuspid valve gasket <NUM>, slit <NUM> divides valve membrane <NUM>, as well as central protrusion <NUM>, into two substantially symmetrical flaps (also referred to as "segments," "valve flaps," or "leaflets").

Each ligament <NUM> likewise includes a slit therethrough. For example, as best illustrated in <FIG> and <FIG>, each ligament <NUM> includes a ligament slit <NUM> that divides the respective ligament into two relatively symmetrical ligament segments.

In some embodiments of the disclosure, each ligament slit <NUM> can be perpendicular to valve membrane <NUM>. In alternative embodiments, ligament slits <NUM> may be non-normal to valve membrane <NUM>. Thus, it is contemplated that any given ligament slit <NUM> can form an angle of between about <NUM> degrees and about <NUM> degrees, and, more desirably, an angle of between about <NUM> degrees and about <NUM> degrees, with valve membrane <NUM>. Where ligament slits <NUM> are non-normal to valve membrane <NUM>, it is contemplated that they will be generally centered on the entry face of ligaments <NUM>.

Ligaments <NUM> are arranged on valve membrane <NUM> such that their respective ligament slits <NUM> are planarly aligned with membrane slit(s) <NUM> (best illustrated in <FIG>). Indeed, ligament slits <NUM> can be formed at the same time as membrane slit(s) <NUM> by cutting through both valve membrane <NUM> and ligaments <NUM> at once.

As shown in <FIG>, bicuspid valve gasket <NUM> includes two ligaments <NUM> positioned about <NUM> degrees from each other (e.g., along slit <NUM>). Thus, each of the two flaps of bicuspid valve gasket <NUM> is bounded along its outer circumferential edge by annular wall <NUM>, along its inner circumferential edge by central protrusion <NUM>, and on its radial edges by segments of ligaments <NUM>.

As illustrated to good advantage in <FIG>, annular wall <NUM> includes a first, more proximal, generally cylindrical portion 42a and a second, more distal, beveled (or frustoconical) portion 42b. A plurality of positioning protrusions <NUM> extend in an axial direction from the exit face of generally cylindrical portion 42a. Correspondingly, a plurality of positioning recesses <NUM> are set radially into a circumferential surface of beveled portion 42b, in between respective positioning protrusions <NUM> and beveled surfaces <NUM>. According to aspects of the disclosure, positioning protrusions <NUM> alternate with positioning recesses <NUM> around the circumference of annular wall <NUM>.

In some embodiments of the disclosure, the plurality of positioning recesses <NUM> are geometrically complementary to the plurality of positioning protrusions <NUM>. For example, each positioning recess <NUM> can include a convex surface that is configured to mate with a corresponding concave surface on a respective positioning protrusion <NUM>.

According to aspects of the disclosure, the plurality of positioning recesses <NUM> are substantially aligned with membrane slit(s) <NUM>. Thus, for example, bicuspid valve gasket <NUM> includes two positioning protrusions <NUM> and two positioning recesses <NUM>, alternately disposed around annular wall <NUM> at about <NUM>-degree intervals. As described further below, this configuration helps ensure that a hemostasis valve system <NUM> including two bicuspid valve gaskets <NUM> arranged back-to-back will achieve a good seal. Of course, the same result could be achieved equally well with the plurality of positioning protrusions <NUM> aligned with the membrane slit(s) <NUM>.

<FIG> are various views of a valve gasket <NUM> according to a second embodiment disclosed herein. For reasons that will be clear upon reviewing the following disclosure, the embodiment of <FIG> can be referred to as a "biomimetic tricuspid valve gasket" (or simply a "tricuspid valve gasket"). <FIG> are perspective views of tricuspid valve gasket <NUM>, with <FIG> emphasizing the entry face of tricuspid valve gasket <NUM> and <FIG> emphasizing the exit face of tricuspid valve gasket <NUM>. <FIG> is a planar view looking towards the entry face of tricuspid valve gasket <NUM>. <FIG> is a planar view looking towards the exit face of tricuspid valve gasket <NUM>. <FIG> is a cross-sectional view taken along line E-E in <FIG>.

Tricuspid valve gasket <NUM> shares many structural features in common with bicuspid valve gasket <NUM>. For example, tricuspid valve gasket <NUM> includes an annular wall <NUM> (having both a generally cylindrical portion 42a and a beveled or frustoconical portion 42b), a central protrusion <NUM> with guiding recess <NUM>, a plurality of ligaments <NUM>, and a valve membrane <NUM>. Likewise, central protrusion <NUM> and valve membrane <NUM> include slits <NUM> therethrough, with ligaments <NUM> similarly including ligament slits <NUM>.

Tricuspid valve gasket <NUM> also includes a plurality of positioning protrusions <NUM>, beveled surfaces <NUM>, and positioning recesses <NUM> therebetween. In particular, tricuspid valve gasket <NUM> includes three positioning protrusions <NUM> and three positioning recesses <NUM>, alternately disposed around annular wall <NUM> at about <NUM>-degree intervals.

Tricuspid valve gasket <NUM> differs, however, in the number of ligaments <NUM>, membrane slits <NUM>, and ligament slits <NUM>. Specifically, tricuspid valve gasket <NUM> includes three ligaments <NUM> with corresponding ligament slits <NUM> and three slits <NUM> through membrane <NUM> and central protrusion <NUM>. Ligaments <NUM> and slits <NUM> are disposed at about <NUM> degree intervals, thus dividing sealing assembly <NUM> of tricuspid valve gasket <NUM> into three substantially congruent flaps. As with bicuspid valve gasket <NUM>, each flap is bounded along its outer circumferential edge by annular wall <NUM>, along its inner circumferential edge by central protrusion <NUM>, and along its radial edges by segments of ligaments <NUM>.

<FIG> illustrate a hemostasis valve system <NUM> as an assembly of two bicuspid valve gaskets 40a, 40b. <FIG> illustrate a hemostasis valve system <NUM> as another assembly of two tricuspid valve gaskets 70a, 70b.

In either case (and, indeed, in general in accordance with the instant teachings), the two valve gaskets 40a, 40b or 70a, 70b are positioned back-to-back (that is, exit face-to-exit face) such that the positioning protrusions 60a of the first gasket 40a, 70a mate into the positioning recesses 62b of the second gasket 40b, 70b, and vice versa, with tight interfacial contact between the respective valve membranes <NUM>. Because valve membrane and ligament slits <NUM>, <NUM> on each gasket 40a, 40b or 70a, 70b are aligned with the positioning recesses 62a, 62b, the slits <NUM>, <NUM> on one valve gasket 40a, 70a will be rotationally offset from the slits <NUM>, <NUM> on other valve gasket 40b, 70b when assembled together as shown and described.

For instance, slits <NUM>, <NUM> on one valve gasket 40a will be rotationally offset by about <NUM> degrees from slits <NUM>, <NUM> on the other valve gasket 40b when the two are assembled together with tight interfacial contact between the exit faces of their respective valve membranes. Similarly, slits <NUM>, <NUM> on one valve gasket 70a will be rotationally offset by about <NUM> degrees from slits <NUM>, <NUM> on the other valve gasket 70b when the two are assembled together with tight interfacial contact between the exit faces of their respective membranes.

Thus, any gap that forms between a flap of one valve gasket 40a or 70a and an interventional medical device inserted therethrough will be misaligned with any gap that forms between a flap of the other valve gasket 40b or 70b and the same interventional medical device. This ensures that a hemostasis valve system <NUM> achieves a good seal and prevents fluid passage through both valve gaskets 40a, 40b or 70a, 70b.

Likewise, the back-to-back configuration for assembling two valve gaskets and use of ligaments <NUM> on individual valve gaskets advantageously renders hemostasis valve system <NUM> according to the instant disclosure self-sealing. In particular, ligaments <NUM> will result in valve membranes <NUM> exhibiting a greater resistance to axial stretching than to radial or transverse compression when an interventional medical device is inserted or withdrawn through hemostasis valve system <NUM>. This, in turn, will minimize axial deformation of the valve gaskets, and desirably reduce the potential for air embolism during the insertion and withdrawal of an interventional medical device.

That is, when an interventional medical device is inserted through the entry face of a valve gasket according to the instant disclosure, ligaments <NUM> will permit axial distension of the flaps. If, on the other hand, the interventional medical device is inserted through the exit face of the valve gasket, ligaments <NUM> will resist axial distension. Instead, both valve gaskets, as an integral hemostasis valve system <NUM>, will be compressed radially, resulting in improved conformance to the outer profile of the interventional medical device and, in turn, a tighter seal against the interventional medical device.

Therefore, when two valve gaskets as disclosed herein are assembled in back-to-back arrangement, it does not matter from which direction an interventional medical device is inserted through hemostasis valve system <NUM>. In either insertion direction, the ligaments <NUM> of one valve gasket will permit axial distension while the ligaments <NUM> of the other valve gasket will resist axial distension in favor of radial compression, thus minimizing the risk of air embolism.

Suitable materials for valve gaskets as disclosed herein include various compliant and highly elastic polymeric materials, as well as polymeric foams with high resiliency. These include, without limitation, silicone rubber, urethane rubber, natural rubber (isoprene), and other synthetic hydrocarbon rubber materials (e.g., ethylene-propylene-diene elastomer, styrenebutadiene rubber, neoprene rubber, nitrile or Buna-N rubber, butyl rubber, fluoroelastomers and the like). Certain thermoplastic elastomers (e.g., styrenic, olefinic, polyester-based, and polyamide-based block copolymers and the like) and/or thermoplastic vulcanizates (e.g., thermoplastic polypropylene with vulcanized silicone rubber, thermoplastic polyurethane with vulcanized silicone rubber, and the like) may also be suitable.

Although several embodiments have been described above with a certain degree of particularity, those skilled in the art could make numerous alterations to the disclosed embodiments.

For example, although biomimetic bicuspid and tricuspid valve gasket embodiments have been described in detail above, it should be understood that the teachings herein can be applied to a valve gasket with any number of flaps (or segments), including configurations that may not be biomimetic.

In this regard, <FIG> depict a valve gasket <NUM> that includes four substantially congruent flaps, and a hemostasis valve assembly <NUM> utilizing two such gaskets 75a, 75b, while <FIG> depict a valve gasket <NUM> that includes five substantially congruent flaps, and a hemostasis valve assembly <NUM> utilizing two such gaskets 80a, 80b. It should be understood that valve gaskets <NUM> and <NUM> share many structural features in common with bicuspid valve gasket <NUM> and tricuspid valve gasket <NUM>, and differ primarily in the number of flaps and the number and placement of ligaments, slits, positioning protrusions, and positioning recesses.

As another example, the flaps (or segments) need not be substantially equal in size, as results from regular spacing of the ligaments and slits around the central protrusion. Instead, the ligaments and slits can be positioned at irregular intervals around the central protrusion, yielding some flaps (or segments) that are larger than others.

All directional references (e.g., upper, lower, upward, downward, left, right, leftward, rightward, top, bottom, above, below, vertical, horizontal, clockwise, and counterclockwise) are only used for identification purposes to aid the reader's understanding of the present invention, and do not create limitations, particularly as to the position, orientation, or use of the invention. Joinder references (e.g., attached, coupled, connected, and the like) are to be construed broadly and may include intermediate members between a connection of elements and relative movement between elements. As such, joinder references do not necessarily infer that two elements are directly connected and in fixed relation to each other.

Claim 1:
A valve gasket (30a, 30b, <NUM>, 40a, 40b, <NUM>, 70a, 70b, <NUM>, 80a, 80b), comprising:
an annular wall (<NUM>);
a plurality of ligaments (<NUM>) attached to and extending radially inward from the annular wall (<NUM>), wherein each ligament (<NUM>) of the plurality of ligaments (<NUM>) includes a ligament slit (<NUM>) that divides the ligament into two ligament segments; and
a membrane (<NUM>) surrounded by the annular wall (<NUM>) and attached to the plurality of ligaments (<NUM>) and to the annular wall (<NUM>), wherein the membrane (<NUM>) includes at least one membrane slit (<NUM>) that divides the membrane (<NUM>) into a plurality of flaps,
wherein the plurality of ligaments (<NUM>) are positioned with the plurality of ligament slits (<NUM>) aligned with the at least one membrane slit (<NUM>), such that each flap is bounded along a circumferential edge by the annular wall (<NUM>), along a first radial edge by a first ligament segment, and along a second radial edge by a second ligament segment.