Regulation of pressure differentials in interventional medical devices

Abstract

Devices to minimize the passage of air across a introducer's hemostasis valve when a medical device is inserted therethrough. A kit includes a sheath (12) and a sheath hub (20) attached to the proximal end of the sheath. The sheath hub includes a housing (26), a proximal cap (28) that defines an aperture (29) into the housing, and a hemostasis valve gasket (30) within the housing. The kit also includes a straightener (32) with a cross-section that prevents advancement of the straightener through the aperture of the sheath hub far enough to breach the gasket. The sheath can also include a pressure equalizer configured to equalize a pressure within the sheath lumen ahead of a leading edge of the medical device moving therethrough with a pressure within the sheath lumen behind the leading edge of the medical device moving therethrough without drawing air through the hemostasis valve assembly.

Description

REGULATION OF PRESSURE DIFFERENTIALS ININTERVENTIONAL MEDICAL DEVICESCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of United States provisional application no. 63 / 610,636, filed 15 December 2023, which is hereby incorporated by reference in its entirety as though fully set forth herein.FIELD

[0002] The present disclosure relates generally to medical procedures that involve introducing interventional medical devices into a patient’s vasculature through an introducer. In particular, the instant disclosure relates to devices and techniques that regulate pressure differentials that may arise when an interventional medical device is inserted into and moving through an introducer.BACKGROUND

[0003] 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 Seidinger technique, are known.

[0004] The Seidinger 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, an introducer (sometimes also referred to as a “sheath” or “introducer sheath”) can be inserted over the directing guidewire, followed by the advancement of the introducer along the guidewire into the vasculature until the distal end of the introducer reaches the target location of the vasculature or anatomical structure e.g., the heart) for an intended medical procedure. Steerable introducers, such as the Agilis™ NxT steerable introducer (Abbott Laboratories; Abbott Park, IL), which can be advanced through the vasculature without the use of a guidewire, are also known.

[0005] In any event, the central lumen of the introducer establishes a safe 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. To minimize blood loss or leakage from the introducer, and to reduce the risk of introducing air, introducers typically include a hub (or “cannula”) incorporating a hemostasis valve system at their proximal end. The hemostasis valve system typically includes one or more valve gaskets contained within a housing.

[0006] Those of skill in the art will appreciate that, as the interventional medical device moves through the lumen of the introducer, it can create a plunger effect, where the pressure on one side of the leading edge of the interventional medical device differs from the pressure on the opposite side of the leading edge of the interventional medical device (in this context, the term “leading edge” refers to the distal end of the interventional medical device). For instance, as the interventional medical device is advanced into the introducer, the pressure ahead of the leading edge (e.g, distal of the distal end of the interventional medical device) may be higher than the pressure behind the leading edge (e.g, proximal of the distal end of the interventional medical device). Conversely, as the interventional medical device is withdrawn from the introducer, the pressure ahead of the leading edge (e.g, distal of the distal end of the interventional medical device) may be lower than the pressure behind the leading edge (e.g., proximal of the distal end of the interventional medical device).

[0007] It is also known to use a straightener to facilitate passage of interventional medical devices, particularly those having complex distal geometries, into the proximal end of the introducer. Extant straighteners are typically designed to bypass the hemostasis valve system by physically opening the gasket(s), such that the interventional medical device can pass through the straightener and into the central lumen of the introducer unimpeded.BRIEF SUMMARY

[0008] Disclosed herein is a kit for access to a patient’s vasculature. The kit includes a sheath having a proximal end; a sheath hub attached to the proximal end of the sheath, the sheath hub including a housing, a proximal cap, and a hemostasis valve gasket disposed within the housing, wherein the proximal cap defines an aperture into the housing; and a straightener,wherein the straightener includes a transverse cross-sectional configuration that prevents advancement of the straightener through the aperture of the sheath hub to an extent sufficient to breach the hemostasis valve gasket.

[0009] The transverse cross-sectional configuration of the straightener may not be congruent to a shape of the aperture. For instance, the aperture can include a circular aperture, the straightener can include a cylindrical body, and an outer diameter of the cylindrical body can exceed a diameter of the circular aperture. As another example, the aperture can include a circular aperture, the straightener can include a frustoconical segment, a minimum outer diameter of the frustoconical segment can be smaller than a diameter of the circular aperture, and the outer diameter of the frustoconical segment can expand from the minimum outer diameter to an interfering outer diameter that is larger than the diameter of the circular aperture.

[0010] Also disclosed herein is a sheath for vascular access. The sheath includes: a shaft defining a lumen therethrough; a sheath hub attached to a proximal end of the shaft, the sheath hub comprising a hemostasis valve assembly; a pressure equalizer configured to equalize a pressure within the lumen ahead of a leading edge of an elongate medical device moving through the lumen with a pressure within the lumen behind the leading edge of the elongate medical device moving through the lumen without drawing air through the hemostasis valve assembly.

[0011] According to aspects of the disclosure, the pressure equalizer includes a fluid inlet through a wall of the shaft, wherein the fluid inlet is positioned distally of the hemostasis valve assembly and behind the leading edge of the elongate medical device moving through the lumen. A fluid reservoir, which can include a low-friction syringe filled with a fluid or a reservoir constructed of a flexible material (e.g., a saline bag), is optionally coupled to the fluid inlet.

[0012] In other aspects of the disclosure, the pressure equalizer includes an irrigation flow controller configured to adjust a flow rate of an irrigation fluid into the lumen through the sheath hub distal of the hemostasis valve assembly. The irrigation flow controller may be configured to adjust the flow rate of the irrigation fluid responsive to a rate of change in position of the elongate medical device relative to the sheath. For instance, a first position sensor may be coupled to the elongate medical device, a second position sensor may be coupled to the sheath, and the rate of change in position of the elongate medical device relative to the sheath may bedetermined using an output of the first position sensor and an output of the second position sensor.

[0013] Alternatively or additionally, the irrigation flow controller may be configured to adjust the flow rate of the irrigation fluid responsive to a measured pressure difference between the pressure within the lumen ahead of the leading edge of the elongate medical device and the pressure within the lumen behind the leading edge of the elongate medical device. For instance, a first pressure sensor can be positioned within the lumen ahead of the leading edge of the elongate medical device, a second pressure sensor can be positioned within the lumen behind the leading edge of the elongate medical device, and the measured pressure difference can be measured using an output of the first pressure sensor and an output of the second pressure sensor.

[0014] The instant disclosure also provides a method of regulating pressure differentials across a leading edge of an elongate medical device moving through a lumen of a sheath. The method includes: facilitating introduction of a fluid behind the leading edge of the elongate medical device as it moves through the lumen to equalize a pressure within the lumen ahead of the leading edge of the elongate medical device with a pressure within the lumen behind the leading edge of the elongate medical device, wherein the fluid is not air drawn into the lumen through a hemostasis valve assembly coupled to a proximal end of the sheath.

[0015] One contemplated approach to facilitating introduction of a fluid behind the leading edge of the elongate medical device includes forming a fluid inlet into the lumen, wherein the fluid inlet is positioned distally of the hemostasis valve assembly and behind the leading edge of the elongate medical device moving through the lumen. It is desirable for the fluid inlet to be positioned at a point along the sheath that will be within a patient’s vasculature during use of the sheath.

[0016] Another contemplated approach to facilitating introduction of a fluid behind the leading edge of the elongate medical device includes coupling a fluid reservoir to the fluid inlet. In certain aspects, the fluid reservoir includes a low-friction syringe or a reservoir constructed of a flexible material (e.g., a saline bag).

[0017] It is also regarded as within the scope of the disclosure to provide an irrigation flow controller configured to adjust a flow rate of an irrigation fluid from the fluid reservoir into the lumen through the fluid inlet. The irrigation flow controller can be configured to adjust the flowrate of the irrigation fluid responsive to a rate of change in position of the elongate medical device relative to the sheath and / or responsive to a measured pressure difference between the pressure within the lumen ahead of the leading edge of the elongate medical device and the pressure within the lumen behind the leading edge of the elongate medical device.

[0018] Also disclosed herein is a sheath for vascular access. The sheath includes: a shaft defining a lumen therethrough; a sheath hub attached to a proximal end of the shaft, the sheath hub including a hemostasis valve assembly; a flush chamber between the hemostasis valve assembly and the lumen of the shaft, the flush chamber including an outlet port; a first valve between the flush chamber and the lumen of the shaft; and a second valve positioned at the outlet port of the flush chamber, the second valve comprising a one-way valve oriented to permit fluid outflow from the flush chamber.

[0019] 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.BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a side, partially cut-away view illustration of the Seidinger technique for vascular access.

[0021] Figure 2 is a cross-sectional view of a representative introducer comprising a hub within which an integral hemostasis valve system is disposed.

[0022] Figures 3 A through 3C depict the use of a straightener to collapse the distal end of an electrophysiology catheter for introduction through an introducer.

[0023] Figure 4 is a schematic illustration of the interaction between a straightener according to aspects of the instant disclosure and an introducer.

[0024] Figure 5A illustrates negative pressure transients that may arise as an interventional medical device is advanced through an introducer.

[0025] Figure 5B illustrates negative pressure transients that may arise as an interventional medical device is withdrawn from an introducer.

[0026] Figure 6 depicts passive approaches to pressure equalization to mitigate negative pressure transients.

[0027] Figure 7 depicts active approaches to pressure equalization to mitigate negative pressure transients.

[0028] Figure 8 is a perspective view of an exemplary steerable introducer according to additional aspects of the instant disclosure.

[0029] Figure 9 is a partially cut-away view of the handle of the steerable introducer of Figure 8 that makes various internal features thereof visible.

[0030] 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. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive.DETAILED DESCRIPTION

[0031] The instant disclosure provides apparatus and methods for regulating pressure differentials that may arise during introduction and / or withdrawal of an interventional medical device via an introducer sheath. 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.

[0032] Referring now to the drawings, Figure 1 depicts the introduction of various medical devices, including guidewire 10, cardiovascular introducer 18, and dilator 14, into a blood vessel 16 using the Sei dinger technique. Insofar as the ordinarily-skilled artisan will be familiar with the Seidinger technique, it need not be described in further detail herein. Likewise, those of ordinary skill in the art will be familiar with other approaches to introducing medical devices into blood vessel 16, including the use of steerable introducers.

[0033] As Figure 1 illustrates, cardiovascular introducer 18 includes an introducer sheath 12, a hub 20, a hemostasis valve system 30, and a side-port fluid tubing 22 with an associated stopcock assembly 24. As shown in Figure 2, hub 20 includes a cap 28 and a housing 26 circumferentially sealed together, within which an integral hemostasis valve system 30 (including, by way of example only, two hemostasis valve gaskets 30a, 30b) is disposed at its proximal end. Side-port fluid tubing 22 and associated stopcock assembly 24 are also coupled tohub 20 or housing 26 to enable the introduction of medical fluids (e.g, saline) through cardiovascular introducer 18 or introducer sheath 12 for an intended clinical procedure.

[0034] Figure 2 is a cross-sectional view of cardiovascular introducer 18 incorporating an integral hemostasis valve system 30 within a circumferentially-sealed hub 20. Various details of hub 20, including housing 26 and cap 28, will be familiar to those of ordinary skill in the art; thus, hub 20 will only be described herein to the extent necessary to understand the instant disclosure.

[0035] The exterior of hub 20 is defined by housing 26 and cap 28. Cap 28 defines an aperture 29 into housing 26 (e.g, an opening through which various interventional medical devices may be inserted through hub 20, into introducer sheath 20, and thus into blood vessel 16.

[0036] Contained within circumferentially sealed housing 26 by cap 28 are one or more hemostasis valve gaskets, such as a first (or proximal) valve gasket 30a and a second (or distal) valve gasket 30b as described in international patent application publication no. WO 2022 / 245598, which is hereby incorporated by reference as though fully set forth herein. Of course, other hemostasis valve gasket configurations and arrangements are regarded as within the spirit and scope of the present disclosure, and the foregoing reference is merely exemplary rather than limiting. As fully assembled and constrained within housing 26, first and second valve gaskets 30a, 30b may be collectively referred to as a hemostasis valve system 30.

[0037] Figures 3A-3C illustrate the use of a straightener 32 to prepare an electrophysiology catheter 34 for insertion into cardiovascular introducer 18 through hub 20. As shown in Figure 3A, electrophysiology catheter 34 includes a shaft 36 and a basket electrode 38 surrounding a balloon 40 at the distal end thereof. Of course, this particular configuration of the distal end of electrophysiology catheter 34 is merely illustrative, such that the teachings herein can be applied to good advantage in connection with any complex distal shape of electrophysiology catheter 34 (e.g, various curves and spirals, paddle shapes, and the like).

[0038] As shown in Figure 3B, by advancing straightener 32 over shaft 36, basket electrode 38 and balloon 40 can be collapsed into a lower-profile, generally cylindrical shape similar to that of shaft 36. This lower-profile shape may be more conducive to inserting electrophysiology catheter 34 into cardiovascular introducer 18 through hub 20, as shown in Figure 3C, bymitigating the difficulty that would attend inserting basket electrode 38 into aperture 29 in the expanded configuration shown in Figure 3A.

[0039] Figure 4 schematically depicts the interaction between straightener 32 and hub 20 of cardiovascular introducer 18. As shown in Figure 4, straightener 32 includes a transverse cross- sectional configuration that prevents advancement of straightener 32 through aperture 29 of cap 28 to an extent sufficient to breach hemostasis valve system 30 (e.g., it will not go far enough to penetrate valve gasket 30a, 30b).

[0040] To this objective, the transverse cross-section of straightener 32 can be configured to be non-congruent to the shape of aperture 29. For example, in some embodiments of the disclosure, the transverse cross-sectional configuration of straightener 32 can have a different shape than aperture 29.

[0041] In other embodiments of the disclosure, straightener 32 includes a cylindrical body, and therefore has a generally circular transverse cross-sectional configuration. The outer diameter of straightener 32 can, however, exceed the diameter of a circular aperture 29, which prevents straightener 32 from being inserted into hub 20 far enough to breach hemostasis valve system 30.

[0042] As shown to good advantage in Figure 4, straightener 32 can include a frustoconical segment 42. The minimum outer diameter of frustoconical segment 42 may be small enough to pass through a circular aperture 29. The outer diameter of frustoconical segment 42 expands from this point, however, to an interfering outer diameter that is larger than the diameter of a circular aperture 29, which stops straightener 32 from further insertion.

[0043] Once straightener 32 is placed as far into hub 20 as possible, electrophysiology catheter 34 can be advanced forward, across hemostasis valve system, and through introducer sheath 12 to the desired destination within the patient’s vasculature.

[0044] As briefly mentioned above, as electrophysiology catheter 34 is advanced through introducer sheath 12, a transient negative pressure can be induced on the trailing (that is, proximal) side 50 of the distal end of electrophysiology catheter 34. This phenomenon is illustrated in Figure 5A (straightener 32 is omitted from Figure 5A for the sake of clarity of illustration).

[0045] Similarly, as electrophysiology catheter 34 is withdrawn from introducer sheath 12, a transient negative pressure can be induced on the trailing (that is, distal) side 52 of the distal end of electrophysiology catheter 34, particularly if the distal end 54 of introducer sheath 12, and any vent holes 56 thereon, are occluded by tissue 58 (which would prevent blood from flowing into trailing side 52 to equalize the pressure). This phenomenon is illustrated in Figure 5B (once again, straightener 32 is omitted for the sake of clarity of illustration).

[0046] Those of ordinary skill in the art will appreciate that higher rates of insertion or withdrawal of electrophysiology catheter 34 will result in larger negative pressure transients. If the negative pressure transient exceeds the limits of hemostasis valve system 30, a fluid can cross hemostasis valve system 30 to equalize the pressure, which may be undesirable.

[0047] Accordingly, aspects of the instant disclosure relate to a pressure equalizer that is configured to mitigate negative pressure transients by allowing the pressure within the lumen of introducer sheath 12 on opposite sides of the distal end of electrophysiology catheter 34 as it moves within introducer sheath 12 to equalize without a fluid crossing hemostasis valve system 30. For the sake of explanation, various pressure equalizers will be described with reference to ameliorating negative pressure transients that occur behind (that is, proximally of) the distal end of electrophysiology catheter 34 as it is advanced through introducer sheath 12 (e.g., the scenario illustrated in Figure 5A). Those of ordinary skill in art will understand how to adapt the ensuing teachings herein to ameliorate negative pressure transients that arise during withdrawal of electrophysiology catheter 34 from introducer sheath 12 (e.g., the scenario illustrated in Figure 5B)

[0048] In certain aspects of the instant disclosure, the pressure equalizer facilitates introduction of a fluid, other than a fluid drawn across hemostasis valve system 30, into the lumen 62 of introducer sheath 12. For example, one or more fluid inlets into lumen 62, such as vent holes 60 formed in the wall of introducer sheath 12, may be provided. Vent holes 60 may be placed distally of hemostasis valve system 30, but proximal of the distal end of electrophysiology catheter 34 moving through lumen 62. Moreover, it is desirable for vent holes 60 to be positioned such that they are within the patient’s vasculature during use (e.g., they are sufficiently far away from the distal end of handle 64 of cardiovascular introducer 18 that they lie within the body during a procedure). With vent holes 60 positioned in this manner, negativepressure transients that arise behind the moving distal end of electrophysiology catheter 34 may be ameliorated via the introduction of blood through vent holes 60.

[0049] In certain aspects of the disclosure, vent holes 60 are positioned more than about 1 inch away from distal vent holes 56, such as about 3 inches away from distal vent holes 56, in a proximal direction.

[0050] Alternatively, a fluid reservoir 66 may be coupled to supply a fluid, such as saline, through vent holes 60 to ameliorate negative pressure transients that arise behind the moving distal end of electrophysiology catheter 34. It is contemplated that a low-friction syringe or a fluid container constructed of a flexible material, such as a saline bag, can be used as fluid reservoir 66.

[0051] The foregoing approaches to pressure equalization within lumen 62 may generally be referred to as “passive approaches,” in that the pressure-equalizing fluid is permitted to flow passively as necessary to relieve negative pressure transients. Active approaches, where the flow of the pressure-equalizing fluid is affirmatively controlled by an irrigation flow controller 70 (see Figure 7), are also contemplated.

[0052] As shown in Figure 7, irrigation flow controller 70 is coupled to fluid reservoir 66 to control the delivery of fluid from reservoir 66 to lumen 62 through side-port fluid tubing 22.That is, irrigation flow controller 70 can control the flow of irrigant into cardiovascular introducer 18.

[0053] In an aspect of the instant disclosure, flow controller 70 is configured to adjust the flow rate of irrigant into cardiovascular introducer 18 in response to a rate of change in position of electrophysiology catheter 34 relative to introducer sheath 12, thus allowing the irrigant flow rate to be matched to the rate of insertion of electrophysiology catheter 34. For instance, electrophysiology catheter 34 and introducer sheath 12 may each carry one or more position sensors (e.g., electrodes and / or magnetic coils) to enable the relative positions thereof to be determined by an electroanatomical mapping system 72 (e.g., Abbott Laboratories’ EnSite Precision™ Cardiac Mapping System). The position information determined by electroanatomical mapping system 72 may be input to flow controller 70 and used by flow controller 70 to increase or decrease the irrigant flow rate to mitigate negative pressure transients according to the rate of insertion of electrophysiology catheter 34 through introducer sheath 12.(Those of ordinary skill in the art will appreciate that flow controller 70 could equally well be integrated into the electroanatomical mapping system as into a stand-alone controller as shown in Figure 7.)

[0054] In another aspect of the instant disclosure, flow controller 70 is configured to adjust the flow rate of irrigant into cardiovascular introducer 18 in response to measured pressure differentials on opposite sides of the moving distal end of electrophysiology catheter 34. For instance, two pressure sensors 74a, 74b may be provided within lumen 62, with one positioned relatively near the proximal end of lumen 62 (to measure pressure proximally of the moving distal end of electrophysiology catheter 34) and the other positioned relatively near the distal end of lumen 62 (to measure pressure distally of the moving distal end of electrophysiology catheter 34). Flow controller 70 can use the differential between the pressures measured by sensors 74a, 74b to increase or decrease the irrigant flow rate to mitigate negative pressure transients. For instance, in some embodiments of the disclosure, flow controller 70 is configured to mitigate negative pressure in excess of about 4 psi (e.g., it is configured to increase or decrease the irrigant flow rate to ensure that the pressure differential between sensors 74a, 74b does not exceed about 4 psi).

[0055] Additional aspects of the disclosure relate to a steerable introducer including a flush chamber. Figure 8, for instance, depicts a steerable introducer 80, such as the Agilis™ NxT steerable introducer mentioned above. Those of ordinary skill in the art will be familiar with steerable introducers and will appreciate that such devices typically include various features in common with cardiovascular introducer 18 discussed above, such as introducer sheath 12, hub 20 (including hemostasis valve system30 therein), side-port tubing 22, and stopcock assembly 24.

[0056] Those of ordinary skill in the art will also be familiar with various handles 82 that may be used in connection with steerable introducer 80 (e.g., attached to the proximal end of introducer sheath 12). Handle 82 typically includes one or more actuators, such as knob 84, that, when actuated (e.g., rotated about the longitudinal axis of handle 82), deflect the distal end of introducer sheath 12 to facilitate navigation of introducer sheath 12 through a patient’s vasculature.

[0057] The foregoing and other well-understood aspects of cardiovascular introducer 18 need not be further described herein.

[0058] Figure 9 is a partial cut-away view of handle 82 to show various internal features thereof. In particular, Figure 9 a flush chamber 86 within handle 82. Flush chamber 86 is proximally accessible through hemostasis valve system 30 and is distally in fluid communication with lumen 62 of introducer sheath 12. A one-way valve 88, which has its outlet outside of handle 82, is also in fluid communication with flush chamber 86. An additional valve 90, such as a ball valve, is disposed between flush chamber 86 and lumen 62 of introducer sheath 12.

[0059] In use, an interventional medical device, such as electrophysiology catheter 34, is inserted through hub 20 and into handle 82 with valve 90 closed. With the distal end of electrophysiology catheter 34 positioned within flush chamber 86, flush chamber 86 is filled with a flushing fluid (e.g., saline) via stopcock assembly 34 and side-port tubing 22.

[0060] Once flush chamber 86 is purged of any other fluids, the flushing fluid will begin to exit one-way valve 88 (the flushing fluid is prevented from exiting the proximal end of flush chamber 86 by hemostasis valve system 30 and from exiting the distal end of flush chamber 86 by valve 90). The practitioner can then open valve 90 and advance electrophysiology catheter 34 into lumen 62 of sheath 12 and further into the patient’s vasculature. In this manner, the combination of flush chamber 86 and valve 90 operates in a manner similar to an airlock.

[0061] The following are numbered clauses of the invention:

[0062] Clause 1: A kit for access to a patient’s vasculature, comprising: a sheath having a proximal end; a sheath hub attached to the proximal end of the sheath, the sheath hub comprising a housing, a proximal cap, and a hemostasis valve gasket disposed within the housing, wherein the proximal cap defines an aperture into the housing; and a straightener, wherein the straightener includes a transverse cross-sectional configuration that prevents advancement of the straightener through the aperture of the sheath hub to an extent sufficient to breach the hemostasis valve gasket.

[0063] Clause 2: The kit according to clause 1, wherein the transverse cross-sectional configuration of the straightener is not congruent to a shape of the aperture.

[0064] Clause 3: The kit according to clause 2, wherein: the aperture comprises a circular aperture; the straightener comprises a cylindrical body; and an outer diameter of the cylindrical body exceeds a diameter of the circular aperture.

[0065] Clause 4: The kit according to clause 2, wherein: the aperture comprises a circular aperture; the straightener comprises a frustoconical segment; a minimum outer diameter of the frustoconical segment is smaller than a diameter of the circular aperture; and the outer diameter of the frustoconical segment expands from the minimum outer diameter to an interfering outer diameter that is larger than the diameter of the circular aperture.

[0066] Clause 5: A sheath for vascular access, comprising: a shaft defining a lumen therethrough; a sheath hub attached to a proximal end of the shaft, the sheath hub comprising a hemostasis valve assembly; a pressure equalizer configured to equalize a pressure within the lumen ahead of a leading edge of an elongate medical device moving through the lumen with a pressure within the lumen behind the leading edge of the elongate medical device moving through the lumen without drawing air through the hemostasis valve assembly.

[0067] Clause 6: The sheath according to clause 5, wherein the pressure equalizer comprises a fluid inlet through a wall of the shaft, wherein the fluid inlet is positioned distally of the hemostasis valve assembly and behind the leading edge of the elongate medical device moving through the lumen.

[0068] Clause 7: The sheath according to clause 6 or 7, further comprising a fluid reservoir coupled to the fluid inlet.

[0069] Clause 8: The sheath according to clause 7, wherein the fluid reservoir comprises a low-friction syringe filled with a fluid.

[0070] Clause 9: The sheath according to any of clauses 5 to 8, wherein the pressure equalizer comprises an irrigation flow controller configured to adjust a flow rate of an irrigation fluid into the lumen through the sheath hub distal of the hemostasis valve assembly.

[0071] Clause 10: The sheath according to clause 9, wherein the irrigation flow controller is configured to adjust the flow rate of the irrigation fluid responsive to a rate of change in position of the elongate medical device relative to the sheath.

[0072] Clause 11 : The sheath according to clause 10, further comprising: a first position sensor coupled to the elongate medical device; and a second position sensor coupled to the sheath, wherein the rate of change in position of the elongate medical device relative to the sheath is determined using an output of the first position sensor and an output of the second position sensor.

[0073] Clause 12: The sheath according to clause 9, wherein the irrigation flow controller is configured to adjust the flow rate of the irrigation fluid responsive to a measured pressure difference between the pressure within the lumen ahead of the leading edge of the elongate medical device and the pressure within the lumen behind the leading edge of the elongate medical device.

[0074] Clause 13: The sheath according to clause 12, further comprising: a first pressure sensor positioned within the lumen ahead of the leading edge of the elongate medical device; and a second pressure sensor positioned within the lumen behind the leading edge of the elongate medical device, wherein the measured pressure difference is measured using an output of the first pressure sensor and an output of the second pressure sensor.

[0075] Clause 14: A method of regulating pressure differentials across a leading edge of an elongate medical device moving through a lumen of a sheath, comprising: facilitating introduction of a fluid behind the leading edge of the elongate medical device as it moves through the lumen to equalize a pressure within the lumen ahead of the leading edge of the elongate medical device with a pressure within the lumen behind the leading edge of the elongate medical device, wherein the fluid is not air drawn into the lumen through a hemostasis valve assembly coupled to a proximal end of the sheath.

[0076] Clause 15: The method according to clause 14, wherein facilitating introduction of a fluid behind the leading edge of the elongate medical device comprises forming a fluid inlet intothe lumen, wherein the fluid inlet is positioned distally of the hemostasis valve assembly and behind the leading edge of the elongate medical device moving through the lumen.

[0077] Clause 16: The method according to clauses 15, wherein the fluid inlet is positioned at a point along the sheath that will be within a patient’s vasculature during use of the sheath.

[0078] Clause 17: The method according to any of clauses 15 to 16, wherein facilitating introduction of a fluid behind the leading edge of the elongate medical device comprises coupling a fluid reservoir to the fluid inlet.

[0079] Clause 18: The method according to clause 17, wherein the fluid reservoir comprises a low-friction syringe.

[0080] Clause 19: The method according to clause 17 or 18, wherein facilitating introduction of a fluid behind the leading edge of the elongate medical device comprises providing an irrigation flow controller configured to adjust a flow rate of an irrigation fluid from the fluid reservoir into the lumen through the fluid inlet.

[0081] Clause 20: The method according to clause 19, wherein the irrigation flow controller is configured to adjust the flow rate of the irrigation fluid responsive to a rate of change in position of the elongate medical device relative to the sheath.

[0082] Clause 21 : The method according to clause 19, wherein the irrigation flow controller is configured to adjust the flow rate of the irrigation fluid responsive to a measured pressure difference between the pressure within the lumen ahead of the leading edge of the elongate medical device and the pressure within the lumen behind the leading edge of the elongate medical device.

[0083] Clause 22: A sheath for vascular access, comprising: a shaft defining a lumen therethrough; a sheath hub attached to a proximal end of the shaft, the sheath hub comprising a hemostasis valve assembly; a flush chamber between the hemostasis valve assembly and the lumen of the shaft, the flush chamber including an outlet port; a first valve between the flush chamber and the lumen of the shaft; and a second valve positioned at the outlet port of the flushchamber, the second valve comprising a one-way valve oriented to permit fluid outflow from the flush chamber.

[0084] 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 without departing from the spirit or scope of this invention.

[0085] For instance, rather than responding to changes in relative position or pressure differentials, as described above, flow controller 70 can simply increase the irrigant flow rate to a constant high rate of between about 20 ml / min and about 60 ml / min during insertion and / or withdrawal of electrophysiology catheter 34.

[0086] 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.

[0087] It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not limiting. Changes in detail or structure may be made without departing from the spirit of the invention as defined in the appended claims.

Claims

CLAIMSWhat is claimed is:

1. A kit for access to a patient’ s vasculature, comprising: a sheath having a proximal end; a sheath hub attached to the proximal end of the sheath, the sheath hub comprising a housing, a proximal cap, and a hemostasis valve gasket disposed within the housing, wherein the proximal cap defines an aperture into the housing; and a straightener, wherein the straightener includes a transverse cross-sectional configuration that prevents advancement of the straightener through the aperture of the sheath hub to an extent sufficient to breach the hemostasis valve gasket.

2. The kit according to claim 1, wherein the transverse cross-sectional configuration of the straightener is not congruent to a shape of the aperture.

3. The kit according to claim 2, wherein: the aperture comprises a circular aperture; the straightener comprises a cylindrical body; and an outer diameter of the cylindrical body exceeds a diameter of the circular aperture.

4. The kit according to claim 2, wherein: the aperture comprises a circular aperture; the straightener comprises a frustoconical segment; a minimum outer diameter of the frustoconical segment is smaller than a diameter of the circular aperture; and the outer diameter of the frustoconical segment expands from the minimum outer diameter to an interfering outer diameter that is larger than the diameter of the circular aperture.

5. A sheath for vascular access, comprising:a shaft defining a lumen therethrough; a sheath hub attached to a proximal end of the shaft, the sheath hub comprising a hemostasis valve assembly; a pressure equalizer configured to equalize a pressure within the lumen ahead of a leading edge of an elongate medical device moving through the lumen with a pressure within the lumen behind the leading edge of the elongate medical device moving through the lumen without drawing air through the hemostasis valve assembly.

6. The sheath according to claim 5, wherein the pressure equalizer comprises a fluid inlet through a wall of the shaft, wherein the fluid inlet is positioned distally of the hemostasis valve assembly and behind the leading edge of the elongate medical device moving through the lumen.

7. The sheath according to claim 6, further comprising a fluid reservoir coupled to the fluid inlet.

8. The sheath according to claim 7, wherein the fluid reservoir comprises a low-friction syringe fdled with a fluid.

9. The sheath according to claim 5, wherein the pressure equalizer comprises an irrigation flow controller configured to adjust a flow rate of an irrigation fluid into the lumen through the sheath hub distal of the hemostasis valve assembly.

10. The sheath according to claim 9, wherein the irrigation flow controller is configured to adjust the flow rate of the irrigation fluid responsive to a rate of change in position of the elongate medical device relative to the sheath.

11. The sheath according to claim 10, further comprising: a first position sensor coupled to the elongate medical device; and a second position sensor coupled to the sheath, wherein the rate of change in position of the elongate medical device relative to the sheath is determined using an output of the first position sensor and an output of the second position sensor.

12. The sheath according to claim 9, wherein the irrigation flow controller is configured to adjust the flow rate of the irrigation fluid responsive to a measured pressure difference between the pressure within the lumen ahead of the leading edge of the elongate medical device and the pressure within the lumen behind the leading edge of the elongate medical device.

13. The sheath according to claim 12, further comprising: a first pressure sensor positioned within the lumen ahead of the leading edge of the elongate medical device; and a second pressure sensor positioned within the lumen behind the leading edge of the elongate medical device, wherein the measured pressure difference is measured using an output of the first pressure sensor and an output of the second pressure sensor.

14. A method of regulating pressure differentials across a leading edge of an elongate medical device moving through a lumen of a sheath, comprising: facilitating introduction of a fluid behind the leading edge of the elongate medical device as it moves through the lumen to equalize a pressure within the lumen ahead of the leading edge of the elongate medical device with a pressure within the lumen behind the leading edge of the elongate medical device, wherein the fluid is not air drawn into the lumen through a hemostasis valve assembly coupled to a proximal end of the sheath.

15. The method according to claim 14, wherein facilitating introduction of a fluid behind the leading edge of the elongate medical device comprises forming a fluid inlet into the lumen, wherein the fluid inlet is positioned distally of the hemostasis valve assembly and behind the leading edge of the elongate medical device moving through the lumen.

16. The method according to claim 15, wherein the fluid inlet is positioned at a point along the sheath that will be within a patient’s vasculature during use of the sheath.

17. The method according to claim 15, wherein facilitating introduction of a fluid behind the leading edge of the elongate medical device comprises coupling a fluid reservoir to the fluid inlet.

18. The method according to claim 17, wherein the fluid reservoir comprises a low-friction syringe.

19. The method according to claim 17, wherein facilitating introduction of a fluid behind the leading edge of the elongate medical device comprises providing an irrigation flow controller configured to adjust a flow rate of an irrigation fluid from the fluid reservoir into the lumen through the fluid inlet.

20. The method according to claim 19, wherein the irrigation flow controller is configured to adjust the flow rate of the irrigation fluid responsive to a rate of change in position of the elongate medical device relative to the sheath.

21. The method according to claim 19, wherein the irrigation flow controller is configured to adjust the flow rate of the irrigation fluid responsive to a measured pressure difference between the pressure within the lumen ahead of the leading edge of the elongate medical device and the pressure within the lumen behind the leading edge of the elongate medical device.

22. A sheath for vascular access, comprising: a shaft defining a lumen therethrough; a sheath hub attached to a proximal end of the shaft, the sheath hub comprising a hemostasis valve assembly; a flush chamber between the hemostasis valve assembly and the lumen of the shaft, the flush chamber including an outlet port; a first valve between the flush chamber and the lumen of the shaft; and a second valve positioned at the outlet port of the flush chamber, the second valve comprising a one-way valve oriented to permit fluid outflow from the flush chamber.

Images