Hemostasis seal

A hemostasis seal configured for use in a splittable hemostasis valve, hub, or introducer sheath to permit passage of a medical device therethrough. The seal provides a substantially fluid-tight seal around the medical device without causing excessive frictional resistance that would otherwise unduly restrict movement of the medical device through the seal. In one embodiment, the seal includes first and second resilient seal portions each having a contoured mating surface to provide a first fluid seal with respect to the medical device. The seal also may include one or more projecting portions and one or more mating receiving portions which interact to provide a second fluid seal with respect to the medical device.

TECHNICAL FIELD

The present invention relates generally to the field of medical instruments, and more particularly to hemostasis seals for use during medical procedures.

BACKGROUND

Various medical procedures require the introduction of one or more medical instruments into arteries or veins so that the medical instruments may be advanced to a body location requiring diagnosis or treatment. For example, a guide catheter may be advanced through the patient's vasculature to a desired treatment location, such as the right atrium of the patient's heart, for delivery of a cardiac lead. A mechanism (e.g., a hemostasis valve) including a hemostasis seal may be located at the proximal end of the guide catheter to control or inhibit the flow of blood out of the guide catheter lumen. A cardiac lead or other device (e.g., a guide wire) may be inserted through the seal and the guide catheter lumen and into the patient's vasculature, and the seal inhibits blood flow around the lead.

The seal should accommodate medical devices (e.g., leads, catheters and guide wires) of varying diameters without unduly restricting the movement of the device, yet still effectively seal against the flow of bodily fluids. In addition, the seal may advantageously be designed to be splittable to facilitate removal of the guide catheter while leaving the inner medical device (e.g., guide wire or lead) in place in the patient's body.

Accordingly, there is a need for a splittable or cuttable hemostasis seal which effectively seals against leakage of bodily fluids without unduly resisting the insertion and retraction of elongated cylindrical medical devices of varying diameters.

SUMMARY

The present invention, according to one embodiment, is a hemostasis seal configured to permit passage of a medical device. The seal includes a first resilient seal portion having a first proximal seal member with a first mating surface, a first projecting portion, and a first receiving portion. The seal also includes a second resilient seal portion having a second proximal seal portion with a second mating surface, a second projecting portion, and a second receiving portion. The first mating surface is configured to mate with the second mating surface to form a first fluid seal with respect to the medical device. In addition, the first and second projecting portions are adapted to mate with and sealingly engage the second and first receiving portions, respectively, to form a second fluid seal with respect to the medical device.

In another embodiment, the present invention is a hemostasis seal configured to permit passage of a medical device, and includes a first resilient seal portion with a first mating surface that includes a projecting portion; and a second resilient seal portion with a second mating surface configured to mate with the first mating surface. The second mating surface includes a receiving portion adapted to mate with the projecting portion. The seal is configured such that the first and second seal portions seal around substantially the entire circumferential surface of the medical device when it is passed between the first and second seal portions.

The present invention, in yet another embodiment, is a hemostasis seal configured to permit passage of a medical device. The seal includes a pair of mating seal portions each having a proximal sealing member, a distal projecting member, and a distal receiving portion. The distal receiving portion of each seal portion is sized and shaped to sealingly receive the projecting member of the mating seal portion, and the proximal sealing members and the distal projecting members are configured to sealingly and slidably engage the medical device about substantially an entire circumferential surface thereof when the medical device is passed through the seal.

DETAILED DESCRIPTION

FIG. 1depicts, schematically, a hub assembly10for use in a medical procedure, such as a catheterization procedure, according to one embodiment of the present invention. As can be seen inFIG. 1, the hub assembly10includes a body12having a lumen16therethrough, and a seal50according to one embodiment of the present invention. The lumen16is sized to permit passage of a medical device18such as, for example, a therapy lead, guiding catheter, or a guide wire. The seal50is retained within the hub body12, and is adapted to maintain a substantially positive fluid seal around the medical device18that is passed through the lumen16. The hub10may be coupled to another medical device51such as a catheter or introducer sheath.

FIGS. 2A and 2Bshow proximal and distal perspective views of an assembled seal50according to one embodiment of the present invention. As shown inFIGS. 2A and 2B, the seal50is, in one embodiment, generally cylindrical with a longitudinal axis52and a perimeter53, and is composed of a first seal portion56and a mating second seal portion58. The seal portions56and58are substantially equivalent in overall size and join at a proximal joint64and a distal joint66to form a proximal entrance area70and a distal exit area76. Because the seal50, in one embodiment, is composed of two, separate seal elements, it is particularly adaptable for use in splittable or cuttable medical devices such as splittable hemostasis or bleedback control valves or splittable introducer sheaths. In one embodiment, the seal portions56and58may be attached at or near the seal perimeter using an attachment method that permits the seal50to be readily split or cut.

In general, the shape of the seal50will be dictated by the configuration and requirements of the hemostasis valve, hub, or introducer sheath into which the seal50is inserted. In one embodiment, the seal50is generally cylindrical with an outer diameter D of from about 0.250 inches to about 0.750 inches. In one embodiment, the diameter D is about 0.600 inches. In another embodiment, the diameter D is about 0.450 inches. AlthoughFIGS. 2A and 2Bdepict a cylindrical seal50, this is not a requirement. To the contrary, other shapes (e.g., rectangular, elliptical) are within the scope of the present invention.

In one embodiment, the seal50may be made of polyisoprene. In other embodiments, other resilient materials may be used to form the seal50, including, without limitation, silicone, latex, neoprene, and other rubber-based compounds as will be understood by those of ordinary skill in the art.

In one embodiment, shown inFIGS. 2A and 2B, the proximal entrance area70is generally conical and has an apex78near the longitudinal axis52, and the distal exit area76is concave and may include a generally circular planar portion82disposed about and generally perpendicular to the longitudinal axis52. In one embodiment, the planar portion82has a diameter d of from about 0.030 inches to about 0.100 inches. In one embodiment, the planar portion82has a diameter d of about 0.070 inches. In another embodiment, the planar portion82has a diameter d of about 0.050 inches. In other embodiments, the planar portion82may have a non-circular shape (e.g., rectangular, elliptical)

In one embodiment, the planar portion82may be centered about the longitudinal axis52and, in turn, the apex78of the proximal entrance area70. In another embodiment, either or both of the planar portion82and the apex78of the proximal entrance area70may be offset from the longitudinal axis52.

The seal50may optionally include means for facilitating retention of the seal50within another medical device such as, for example, a hemostasis valve or an introducer sheath. Such means may include a proximal retaining ring90and/or a distal retaining ring92.

FIG. 3shows perspective views of the first and second seal portions56and58, respectively. Additionally,FIGS. 4 and 5are proximal (FIG. 4) and distal (FIG. 5) plan views of the seal portions56and58. As shown inFIGS. 3,4and5, the first seal portion56includes a first proximal sealing member114having a first mating surface118, a first projection132, a first distal wall134defining a first recess136, and a first planar subportion140. The second seal portion58includes a second proximal sealing member146having a second mating surface150, a second projection162, a second distal wall164defining a second recess166, and a second planar subportion170.

In one embodiment, the mating surfaces118and150are each contoured to generally form an ‘S’-shape. Accordingly, in this embodiment, the proximal joint64in the assembled seal50is also ‘S’-shaped (SeeFIG. 2A). In one embodiment, each half of the ‘S’ of the contoured mating surfaces118and150may have a radius of curvature of from about 0.125 inches to about 0.250 inches. In one embodiment, the radius of curvature is about 0.150 inches. In another embodiment, the radius of curvature is about 0.187 inches. In other embodiments, the mating surfaces118and150may be configured in other shapes. When the seal portions56and58are assembled to form the seal50, the proximal sealing members114and146form the proximal entrance area70(SeeFIG. 2A).

In one embodiment, the projections132and162are generally sized and shaped to be inserted into and to sealingly mate with and engage the recesses166and136, respectively, when the seal portions56and58are assembled to form the seal50. When so engaged, the projections132and162generally form the distal exit area76(SeeFIG. 2B). In the assembled seal50, the planar subportions140and170join to form the generally planar portion82(seeFIG. 2B).

The recesses136and166are sized and shaped to receive the projections132and162. In one embodiment, when the seal50is assembled, substantially all of the adjacent surfaces of the projections132and162and the recesses166and136are in sealing contact with one another.

In one embodiment, as shown inFIGS. 3,4and5, the projections132and162and, accordingly, the recesses136and166, are curved, although this is not a requirement of the present invention. In other embodiments, for example, the projections132and162may be substantially triangular or rectangular, and the recesses166and136are shaped to sealingly receive the projections.

As shown inFIGS. 4 and 5, in one embodiment, the first proximal sealing member114intersects the first projection132, and the second proximal sealing member146intersects the second projection162, at approximately 90 degree angles and at approximately the longitudinal axis52. As a result, the proximal sealing members114and146overlap the distal joint66(seeFIG. 2B), and the projections132and162overlap the proximal joint64, at substantially all points other than the longitudinal axis52. As discussed below, this results in sealing around substantially the entire circumferential surface of a medical device (e.g., a cardiac lead) that is inserted through the seal.

FIG. 6is a partial cross-sectional view of the first seal portion56taken along the line X-X inFIG. 4. It should be understood that, although not shown inFIG. 6, the features of the second seal portion58are generally configured to have the same size and shape as the corresponding features of the first seal portion56. For example, the second proximal sealing member146, the second projection162, the second recess166, and the second planar subportion170have generally the same dimensions and shape as the first proximal sealing member114, the first projection132, the first recess136, and the first planar subportion140, respectively.

Thus, as shown inFIG. 6, the proximal sealing members114and146are tapered radially inward, having a thickness t1near the seal perimeter53and a thickness t2near the apex78. In one embodiment, the thickness t1may range from about 0.075 inches to about 0.175 inches, and the thickness t2may range from about 0.005 inches to about 0.025 inches. In one embodiment, the thickness t1is about 0.125 inches and the thickness t2is about 0.0075 inches.

As further shown inFIG. 6, the projections132and162are also thicker near the seal perimeter53than near the longitudinal axis52, and transition into the planar subportions140and170. In one embodiment, the projections132and136have a thickness t3near the perimeter53that may range from about 0.075 inches to about 0.175 inches, and a thickness t4of the planar subportions140and170of from about 0.005 inches to about 0.025 inches. In one embodiment, the thickness t3is about 0.125 inches and the thickness t4is about 0.0075 inches.

In the embodiment shown inFIG. 6, the projections132and162each have a contoured distal face180, although in other embodiments, the projections132and162may have different shapes (e.g., concave) or may have a straight taper similar to the proximal sealing members114and146.

In one embodiment, the thickness t2of the proximal sealing members114and146near the apex78is thicker than the thickness t4of the planar subportions140and170. In one such exemplary embodiment, the thickness t2is about 0.010 inches and the thickness t4is about 0.005 inches.

Table 1 below shows the dimensions, in inches, discussed above for various exemplary embodiments of a seal50according to the present invention.

FIG. 7is a perspective view of the seal50according to one embodiment of the present invention, showing the seal portions56and58partially separated to show how the projections132and162effectively interlock.

FIG. 8is a partial perspective view, andFIG. 9is a partial proximal plan view, of the seal50according to one embodiment of the present invention, with a medical device, such as a therapy lead200, passing therethrough. For clarity, only the second seal portion58is shown inFIGS. 8 and 9. Exemplary medical devices that may be accommodated by the seal50according to one embodiment of the present invention include, without limitation, guide wires, therapy leads, and guide catheters, with outer diameters ranging from about 0.010 inches to about 0.170 inches. As will be apparent to those of ordinary skill in the art, the foregoing types of medical devices and the corresponding ranges of diameters are merely exemplary, and the seal50of the present invention may be adapted to accommodate larger or smaller diameter medical devices as may be required for a particular procedure.

As shown inFIGS. 8 and 9, the proximal sealing members114and146and the projections132and162interact to substantially fully encapsulate the lead200as it is passed between the seal portions56and58. The contoured shape of the mating surfaces118and150tends to cause the proximal sealing members114and146to wrap around the lead200. Similarly, in one embodiment, the projections132and162tend to wrap around the lead200as it passes through the seal50. Working together, the proximal sealing members114and146and projections132and162substantially fully encapsulate a generally cylindrical medical device that is passed between the seal portions56and58.

Additionally, the orientation of the mating surfaces118and150to the projections132and162result in at least the proximal sealing members114and146, or the projections132and162, being in sealing contact with the medical device200around the entire surface of the device. With a seal lacking projections132and162, insertion of a medical device between the seal elements would result in leakage at points approximately 180 degrees apart where the two seal member join. As is apparent inFIGS. 4-7, however, the projections132and162overlap the proximal joint64at all points other than the longitudinal axis52and accordingly, in one embodiment, the apex78, which is the point of entry of the medical device through the seal50. Thus, the projections132and162seal around the medical device immediately distal to any areas of separation that may occur in the proximal joint64. Similarly, the proximal sealing members114and146overlap the distal joint66at all points other than the apex78. This has the resulting effect of sealing around the regions on the medical device proximal of the points of corner separation in the distal joint66. Thus, the inserted medical device, the overlapping proximal sealing members114and146, and the projections132and162interact to eliminate any pathways for leakage of bodily fluids through the seal50.

The projections132and162also operate to stabilize and hold the seal portions56and58in alignment when the lead200or other medical device is inserted through the seal50. A seal without such projections may tend to become misaligned due to, for example, relative translation of the two separate seal components along their joint line, when a device is inserted into or removed from the seal. In the present invention, however, according to one embodiment, the walls128and158in the recesses136and166restrict displacement of the projections132and162, respectively. This in turn restricts relative movement of the seal portions56and58. In addition, the interlocking design of the projections132and162and the recesses136and166, respectively, similarly restricts rotational movement of the seal elements70and76relative to each other.

The stabilizing effect of the projections132and162is further promoted by their profiles. Near the longitudinal axis52, the projections132and162are relatively thin, which promotes effective sealing while at the same time reduces resistance to movement of the lead200or other medical device through the seal50. This provides a beneficial combination of effective sealing without unduly restricting the travel of the medical device through the seal50. At the same time, the thicker portions of the projections132and162near the perimeter of the seal50beneficially stiffens the projections which further inhibits misalignment of the seal portions56and58.

In addition, the geometry of the seal50advantageously promotes centering the medical device, such as the lead200, as it is passed through the seal50. The orientation of the projections132and162at approximately 90 degrees relative to the proximal joint64inhibits the lead200from sliding along the proximal joint64, as would tend to occur if the projections132and162were not present. Accordingly, the projections132and162operate to maintain the lead200or other medical device at a position at or near the longitudinal axis52(seeFIG. 2A).