Patent Description:
During cardiac procedures, blood pressure is often measured and monitored at different areas of the heart to aid in initial diagnosis, to confirm procedural safety, and to verify procedural efficacy. For example, in the context of a mitral valve repair or replacement procedure, right-atrial pressure, left-atrial pressure, and pressure gradients across the mitral valve can be measured during and after the procedure.

Typically, such pressure monitoring is achieved through the use of a pressure wire or fractional flow reserve ("FFR") wire that is inserted into the targeted treatment area of the heart. For example, an operator can introduce a pressure wire into a pulmonary vein to monitor left atrial pressure during a mitral valve repair or replacement procedure. In some circumstances, indirect imaging-based methods are also used to calculate pressure.

Although some degree of intra-procedural pressure monitoring is enabled through these methods, there remains a need for continued improvement. For example, the use of a pressure wire or FFR wire in conjunction with guidewires, catheters, and other components of the procedure can be cumbersome and can increase procedure time. Additionally, in procedures that involve crossing of the septum, monitoring pressure at the targeted area using conventional techniques can require a larger septal puncture, or a second puncture to provide access for a pressure wire to the targeted area.

Accordingly, in many circumstances, the potential benefits of monitoring cardiac pressure intra-procedurally are negated and offset by the foregoing problems. International Application <CIT> describes intra-procedural cardiac pressure monitoring systems for delivering a pressure monitoring sensor to the heart using routing lumens or grooves in a delivery catheter. Such systems can eliminate the need for a second septal puncture to deliver the pressure sensor to the heart. However, there remains a continued need for alternative pressure measurement systems.

The subject matter disclosed herein is not limited to embodiments that solve any issues or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where embodiments described herein can be practiced.

<CIT> discloses delivery devices and interventional devices configured to enable monitoring of pressure and other hemodynamic properties before, during, and/or after a cardiac procedure. A guide catheter includes a routing lumen or a routing groove for routing a sensor wire to a desired location during a cardiac procedure. A guide catheter includes one or more pressure sensors positioned to provide desired pressure measurements when the guide catheter is deploying an interventional device. An interventional device may also include one or more associated sensors for providing hemodynamic information before, during, and/or after deployment.

<CIT> discloses an endovascular device for partitioning the ascending aorta and a system for arresting the heart to facilitate the performance of procedures such as heart valve replacement or coronary artery bypass grafting without the need for a thoracotomy.

The extent of protection is defined by the scope of the claims.

It should be noted that <NUM> inch (in) corresponds to <NUM>.

The purpose and advantages of the disclosed subject matter will be set forth in and apparent from the description that follows, as well as will be learned by practice of the disclosed subject matter. For purpose of illustration and not limitation, the various embodiments described herein relate to interventional delivery systems configured for delivering an interventional device (such as, a valve repair or replacement device, annuloplasty ring, chord replacement or repair device, spacer device, occlusion device, suturing device, or other cardiac interventional device) to a targeted treatment area. The delivery systems are configured to enable the monitoring of hemodynamic properties before, during, and/or after deployment of the interventional device. Additional advantages of the disclosed subject matter will be realized and attained by the methods and systems particularly pointed out in the written description and claims hereof, as well as from the appended drawings.

To achieve these and other advantages, and in accordance with the purpose of the disclosed subject matter, as embodied and broadly described, the disclosed subject matter includes a delivery system for a fixation device, the delivery system including a guide catheter with a proximal end portion having a proximal end port, a distal end portion having a distal end port, and an inner surface defining an inner lumen extending in fluid communication between the proximal end port and the distal end port. The system further includes a delivery catheter extending through the inner lumen of the guide catheter to define an annular space between an outer surface of the delivery catheter and the inner surface of the guide catheter. The system further includes a pressure sensor proximate the proximal end portion of the guide catheter in fluid communication with the annual space to monitor fluid pressure within the annular space. The distal end portion of the guide catheter includes a distal tip member having the distal end port defined therein; the distal tip member comprising a plurality flow passages in fluid communication between an exterior of the distal end portion of the guide catheter and the annular space, the plurality of flow passages comprising a number of flow channels defined in the distal tip member and spaced about a perimeter of the distal end port.

In accordance with an aspect of the disclosed subject matter, the plurality of flow passages collectively can have a total flow area between the exterior of the distal end portion and the annular space of between about <NUM> in<NUM> and <NUM> in<NUM>. Additionally, the delivery system can include a fixation device removably coupled to a distal end of the delivery catheter and configured for fixation to leaflets of a native valve.

The number of flow channels can be spaced equally about the perimeter of the distal end port. For example, the number of flow channels can be four flow channels. For purpose of example and not limitation, each flow channel can have a width of about <NUM> to <NUM> inches. As embodied herein, each flow channel can have a width of about <NUM> inches. Furthermore, each flow channel can have a depth from the perimeter of the distal end port. For purpose of example and not limitation, the depth can be between about <NUM> to about <NUM> inches. As embodied herein, each flow channel can have a depth of about <NUM> inches.

The distal end port can have an inner diameter substantially equal to an outer diameter along a distal end portion of the delivery catheter. For purpose of example and not limitation, the inner diameter can be between about <NUM> and about <NUM> inches. As embodied herein, the inner diameter can be about <NUM> inches. The distal end portion of the guide catheter can include a distal tip member having the distal end port and the flow channels defined therein. The distal tip member can have a durometer hardness measurement of 40D up to 55D or greater. Additionally, or alternatively, the distal tip member can be made of a Pebax material.

In accordance with another aspect, the guide catheter can be a steerable guide catheter. The steerable guide catheter can include a steering mechanism with a plurality of cables extending a length of the guide catheter. The steering mechanism can be adapted to bend the distal end portion of the guide catheter in at least one reference plane. Each flow channel can be offset circumferentially about the perimeter of the distal end port from the reference plane. For purpose of example, and as embodied herein, each flow channel can be offset circumferentially by about <NUM>° from the reference plane.

As embodied herein, the proximal end portion of the guide catheter can include a luer connector in fluid communication with the annular space. The pressure sensor can be removably connectable to the luer connector. The pressure sensor can be a pressure transducer. Furthermore, the proximal end portion can include a hemostasis valve to seal a proximal end of the annual space.

Furthermore, the distal end portion of the guide catheter can include a braided reinforcement.

It is to be understood that both the foregoing general description and the following detailed description are exemplary.

Reference will now be made in detail to the various exemplary embodiments of the disclosed subject matter, which are illustrated in the accompanying drawings. The structure and corresponding method of operation of the disclosed subject matter will be described in conjunction with the detailed description of the system.

The disclosed subject matter is directed to devices, systems, and methods enabling intra-procedural monitoring of cardiac pressure and related hemodynamics. As embodied herein, pressure monitoring can be enabled before, during, and/or after a cardiac procedure. Although the embodiments described herein are directed to a mitral valve repair procedure for purpose of illustration and not limitation, it will be understood that the related principles and/or components can also be applied within the context of another cardiac procedure, such as a mitral valve replacement, tricuspid valve repair or replacement, chordae tendineae repair or replacement, septal defect repair, occlusion, leaflet modification, leaflet plication, or other cardiac procedure where the monitoring of blood pressure or other hemodynamic properties is desired.

In addition, although reference is made to "intra-procedural" pressure monitoring, pre and/or post-procedural pressure monitoring also is contemplated.

Further, although reference is made to various components for measuring blood pressure, it will be understood that such pressure monitoring can, alternatively or additionally, include blood flow monitoring and/or the monitoring of other hemodynamic properties. Accordingly, the terms "sensor," "sensor wire," "transducer," and the like, as user herein, typically refer to pressure-sensing devices, but in other embodiments, can additionally or alternatively refer to flow sensing devices and/or devices configured for measuring other hemodynamic properties. In addition, although various descriptions make reference to "sensor" in the singular, it will be understood that alternative embodiments include one or more sensor arrays having multiple different sensors arranged together as a sensor array unit.

Delivery systems in accordance with the disclosed subject matter generally include a guide catheter with a proximal end portion having a proximal end port, a distal end portion having a distal end port, and an inner surface defining an inner lumen extending in fluid communication between the proximal end port and the distal end port. The system further includes a delivery catheter extending through the inner lumen of the guide catheter to define an annular space between an outer surface of the delivery catheter and the inner surface of the guide catheter. The system further includes a pressure sensor proximate the proximal end portion of the guide catheter in fluid communication with the annual space to monitor fluid pressure within the annular space. The distal end portion of the guide catheter includes a plurality flow passages in fluid communication between an exterior of the distal end portion of the guide catheter and the annular space. In accordance with an aspect of the disclosed subject matter, the plurality of flow passages can collectively have a total flow area between the exterior of the distal end portion and the annular space of between about <NUM> in<NUM> and <NUM> in<NUM>. In accordance with another aspect of the disclosed subject matter, a fixation device can be removably coupled to a distal end of the delivery catheter and configured for fixation to leaflets of a native valve can be provided.

The accompanying figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the disclosed subject matter.

For purpose of illustration, and not limitation, reference is made to the exemplary embodiment of a delivery system shown in <FIG>. The illustrated delivery system <NUM> can be configured as a multi-catheter guiding system for delivering an interventional device <NUM> to a targeted treatment area (e.g., through transapical, transfemoral, or transthoracic introduction). By way of example, the interventional device <NUM> can be a replacement valve (e.g., mitral, tricuspid, aortic, or pulmonary valve), tissue fixation device (e.g., valve clip), chordae tendineae (i.e., chord) replacement or repair device, annuloplasty ring, occluding device, septal defect repair device, spacer, suture device, or other interventional device suitable for use in a structural heart procedure. For purpose of illustration and not limitation, reference is made herein to a delivery system for a tissue fixation device.

The delivery system <NUM> has proximal end <NUM> and a distal end <NUM>. The system <NUM> includes a guide catheter <NUM> having a proximal end portion <NUM>, and a distal end portion <NUM>. As described further herein, the proximal end portion <NUM> includes a proximal end port <NUM> and the distal end portion <NUM> includes a distal end port <NUM>, and an inner lumen extends in fluid communication between the proximal end port <NUM> and the distal end port <NUM>. In accordance with another aspect of the disclosed subject matter, and as described further below, the guide catheter <NUM> can be a steerable guide catheter.

The system <NUM> further includes a delivery catheter <NUM> extending through the inner lumen <NUM> of the guide catheter <NUM>. For purpose of example, and as embodied herein, the delivery catheter <NUM> can include a steerable sleeve <NUM> with an inner shaft <NUM> disposed therein, as described further herein. The steerable sleeve <NUM> can be positioned radially within the guide catheter <NUM>, and inner shaft <NUM> can be positioned radially within the sleeve <NUM>, as shown. An annular space <NUM> is defined between an outer surface <NUM> of the delivery catheter <NUM> and an inner surface <NUM> of the guide catheter <NUM>. As embodied herein, outer surface <NUM> of the deliver catheter <NUM> can be an outer surface of the steerable sleeve <NUM>. The inner shaft <NUM> can be translatable within the steerable sleeve <NUM>, and the steerable sleeve <NUM> can be translatable within the guide catheter <NUM>.

While the system <NUM> is depicted with a guide catheter <NUM> and a delivery catheter <NUM> having a steerable sleeve <NUM> and inner shaft <NUM> disposed therein, those of skill in the art will recognize that delivery systems in accordance with the disclosed subject matter can have alternate configurations. For purpose of example and not limitation, delivery systems can include multiple guide catheters, such as an outer guide catheter and one or more inner guide catheters disposed therein. Alternatively, the delivery system can be a single integral component.

For purpose of example, and as described further below, a fixation device <NUM> can be removably coupled to a distal end of the delivery catheter and configured for fixation to leaflets of a native valve. Manipulation of the guide catheter <NUM> and/or sleeve <NUM> can enable the fixation device <NUM> to be directed through a patient's vasculature to a targeted treatment area of the patient's heart. As embodied herein, angling of the guide catheter <NUM> and the inner sleeve <NUM> can be achieved using the guide catheter handle <NUM> and the sleeve handle <NUM> attached to the proximal ends of the guide catheter <NUM> and the sleeve <NUM>, respectively. As shown, the guide catheter handle <NUM> is coupled to the proximal end of the guide catheter <NUM>, and the sleeve handle <NUM> is coupled to the proximal end of the sleeve <NUM>. The sleeve <NUM> is inserted through the guide catheter handle <NUM> to position the sleeve <NUM> radially within the guide catheter <NUM>. The inner shaft <NUM> is inserted through the sleeve handle <NUM> to position the inner shaft <NUM> radially within the sleeve <NUM> and the guide catheter <NUM>. As embodied herein, an inner shaft can be assembled within a sleeve to limit translation within the sleeve. For example, an inner shaft can have a larger profile than the sleeve at sections of the inner shaft proximal and/or distal to the sleeve according to the order of construction/assembly.

For purpose of illustration, and not limitation, reference is made to the exemplary embodiment of a guide catheter <NUM> shown in <FIG> and <FIG>. The guide catheter <NUM> includes a proximal end portion <NUM> having a proximal end port <NUM> and a distal end portion <NUM> having a distal end port <NUM>. An inner surface <NUM> of the guide catheter <NUM> defines an inner lumen extending in fluid communication between the proximal end port <NUM> and the distal end port <NUM>. The distal end portion <NUM> of the guide catheter <NUM> includes a plurality flow passages <NUM> as described further herein.

As embodied herein, guide catheter <NUM> can have a generally tubular shape, and can be comprised of a material which provides hoop strength while maintaining flexibility and kink resistance, such as a braided laminated material. Such material can include stainless steel braided or coiled wire embedded in a polymer such as polyurethane, polyester, Pebax, Grilamid TR55, and AESNO to name a few. At least a length of the guide catheter <NUM> can include a braided reinforcement. For purpose of example and not limitation, a distal end portion of the guide catheter can include a braided reinforcement. To provide further support and hoop strength, a support coil can be disposed within the lumen of the guide catheter <NUM>.

With reference to <FIG>, guide catheter <NUM> and/or the sleeve <NUM> can be a steerable guide catheter and can include steering mechanisms to position the distal end <NUM> of the guide catheter <NUM> and/or sleeve <NUM> in desired directions. The guide catheter <NUM> can include a steering mechanism having a plurality of cables <NUM>, <NUM> extending a length of the guide catheter. As shown, the guide catheter <NUM> can include a first cable <NUM> slidably disposed in a lumen within the wall of the guide catheter <NUM> and extending a length of the guide catheter to the distal end portion <NUM>. By applying tension to the cable <NUM> in the proximal direction, the distal end <NUM> curves in the direction of the cable <NUM> as illustrated by arrow <NUM>. Likewise, placement of a second cable <NUM> along the opposite side of the guide catheter <NUM> will allow the distal end <NUM> to be curved in the opposite direction, as illustrated by arrow <NUM>, when tension is applied to the second cable <NUM>.

Thus, the opposed cables <NUM> and <NUM> within the walls of the guide catheter <NUM> can enable the distal end <NUM> to be steered or bent in opposite directions. As embodied herein, the steering mechanism can include one or more steering knobs <NUM> and <NUM> for controlling the tensioning of one or more of the cables <NUM>, <NUM> running the length of the guide catheter <NUM> and/or the sleeve <NUM>. This can provide a means of correcting or adjusting a curvature of the guide catheter <NUM> and/or sleeve <NUM> within one or more reference planes. For example, if tension is applied to one cable to create a curvature, the curvature can be lessened by applying tension to the diametrically opposite cable. The illustrated embodiment includes two opposing cables. Other embodiments can include a single cable, or can include more than two cables. In addition, cables and associated lumens can be placed in any arrangement, singly or in pairs, symmetrically or non-symmetrically, to enable desired curvature capabilities. Cables can be fixed at any location along the length of the guide catheter <NUM> by any suitable method, such as gluing, tying, soldering, and the like. When tension is applied to the cable, the curvature forms from the point of attachment of the cable toward the proximal direction. Typically, however, cables are attached near the distal end <NUM> of the guide catheter <NUM>. Additionally, or alternatively, one or more of the guide catheter <NUM> or the sleeve <NUM> can be precurved to provide a desired angling for properly traversing a patient's vasculature in the context of a particular procedural approach.

For example, precurvature or steering of the guide catheter <NUM> can direct the distal end of the guide catheter <NUM> to form a first curve, while precurvature or steering of the sleeve <NUM> can direct the distal end of the sleeve <NUM> to form a second curve. In this manner, the first curve can differ from that of the second curve so that together the curves form a compound curve. For example, for a mitral valve procedure using a transfemoral approach, the primary curve can have a radius of curvature in the range of <NUM> to <NUM> inches and the secondary curve often has a radius of curvature in the range of <NUM> to <NUM> inches. Advancement of the inner shaft <NUM> through the sleeve <NUM> thereby guides the inner shaft <NUM> through the resulting compound curve, and enables the fixation device <NUM> to be delivered to the targeted treatment area in a desired orientation. The interventional device <NUM> can then be actuated, deployed, and/or released through manipulation of the delivery handle <NUM>. As embodied herein, a guide catheter can be configured with precurvature and/or steering functionality so as to accommodate transjugular delivery or other vascular delivery. Alternatively, curvature of both the guide catheter <NUM> and the sleeve <NUM> can be oriented in the same direction to provide an even higher angular curvature about a single axis.

The dimensions of the guide catheter <NUM> can be selected based on the desired use and performance characteristics of the guide catheter <NUM>. For example, smaller outer diameters of the guide catheter <NUM> can be desirable to facilitate navigation through a patient's vasculature. Additionally, the inner diameter of the guide catheter <NUM> can be selected, for example, to accommodate the delivery catheter <NUM> and fixation device <NUM> within the inner lumen of the guide catheter. The inner diameter of the guide catheter can be varied along the length of the guide catheter. For example, and as described further herein, the distal end portion of the guide catheter can be tapered, and the distal end port can have a smaller inner diameter than an inner diameter of a proximal portion of the guide catheter. For purpose of example, and not limitation, the inner diameter of the distal end port <NUM> of the guide catheter <NUM> can be between about <NUM> inches and <NUM> inches. As embodied herein, the inner diameter of the distal end port <NUM> can be about <NUM> inches. The inner diameter of the distal end port <NUM> can be selected such that the distal end port <NUM> has an inner diameter substantially equal to an outer diameter of the delivery catheter <NUM> along a distal end portion of the delivery catheter <NUM>. As embodied herein, the distal end port <NUM> can have an inner diameter substantially equal to an outer diameter of the steerable sleeve <NUM> of the delivery catheter <NUM> along a distal end portion of the delivery catheter <NUM>.

In accordance with the disclosed subject matter, the system <NUM> further includes a pressure sensor <NUM> proximate the proximal end portion <NUM> of the guide catheter <NUM>. The pressure sensor <NUM> is in fluid communication with the annular space <NUM> to monitor fluid pressure within the annular space, as described further herein. The pressure sensor can be placed in fluid communication with the annular space <NUM> using any suitable means. For purpose of example, and as embodied herein, the proximal end portion <NUM> of the guide catheter <NUM> can include a luer connector <NUM> in fluid communication with the annular space. The pressure sensor <NUM> can be removably connectable to the luer connector <NUM>, for example, using tubing <NUM>. For purpose of example, the length of tubing <NUM> can be selected such that the pressure sensor can be positioned at the same height as the patient's heart. Additionally or alternatively, the pressure sensor <NUM> can be removably connected to the luer connector <NUM> without tubing <NUM>. A pressure offset can be applied if the pressure sensor <NUM> is positioned at a different vertical height from the patient's heart to account for changes in pressure due to gravitational forces. The tubing <NUM> used can have a lumen cross sectional area greater than the minimum flow area of the annular space <NUM>.

Those of skill in the art will recognize that various pressure sensors are known in the art. Any suitable pressure sensor can be used with the delivery systems described herein. For purpose of example, and as embodied herein, the pressure sensor can be a pressure transducer. As described further herein, a pressure sensor capable of detecting changes in pressure as small as about <NUM> mmHg can be selected. As described further herein, the pressure sensor <NUM> proximate the proximal end portion of the guide catheter <NUM> can detect changes in pressure transmitted through the annular space <NUM> from exterior of the distal end <NUM> of the guide catheter.

For purpose of example, and as embodied herein, the proximal end portion <NUM> of the guide catheter <NUM> can include a hemostasis valve <NUM> to seal a proximal end of the annular space. The hemostasis valve <NUM> can be configured to reduce the risk of air introduction and to prevent back bleeding during use of the system. As embodied herein, the hemostasis valve <NUM> can form a seal between the proximal end <NUM> of the guide catheter <NUM> and an outer surface of the delivery catheter <NUM>.

With reference to <FIG> and <FIG>, the guide catheter <NUM> includes a plurality of flow passages <NUM> in fluid communication between an exterior of the distal end portion <NUM> of the guide catheter <NUM> and an annular space <NUM> defined between an outer surface <NUM> of the delivery catheter <NUM> and an inner surface <NUM> of the guide catheter <NUM>. In accordance with an aspect of the disclosed subject matter, the plurality of flow passages <NUM> can collectively have a total flow area between the exterior of the distal end portion <NUM> and the annular space <NUM> of between about <NUM> in<NUM> and <NUM> in<NUM>. For purpose of example, and as embodied herein, the flow passages can include four flow channels <NUM> spaced about a perimeter of the distal end port <NUM>. Additionally, or alternatively, the plurality of flow passages <NUM> can include a number of flow openings defined through a wall of the guide catheter, as described further herein.

The configuration of the flow passages <NUM> can be selected to provide the desired total flow area in communication with the annular space <NUM> of sufficient size to accurately monitor pressure exterior of the distal end portion, such as an atrial pressure, using a pressure sensor proximate the proximal end portion of the guide catheter, as described further herein. For example, and for purpose of measuring atrial pressure, it has been determined that a fluid column equivalent to that of a <NUM> Fr catheter is sufficient to obtain accurate atrial pressure measurements.

The flow passages <NUM> can have any suitable shape in end view, including an arcuate shape, substantially triangular shape, or square shape. For purpose of example, and as embodied herein, the flow passages can include four flow channels <NUM>, each having a generally rectangular shape in end view. The dimensions of the flow passages <NUM> can be selected to provide the desired total flow area, as noted above. For example, and with four flow channels <NUM> forming the flow passages, each channel can have a width <NUM> of between about <NUM> inches and <NUM> inches, and a depth measured from the perimeter of the distal port <NUM> of between about <NUM> inches and <NUM> inches. For purpose of example, and with reference to <FIG>, the depth of each flow channel can be calculated by subtracting the guide catheter inner diameter <NUM> from the channelto-channel dimension <NUM> and dividing the difference by two. As embodied herein, each flow channel can have a width <NUM> of about <NUM> inches and a depth of about <NUM> inches.

As will be understood by those of skill in the art, the number of flow passages <NUM>, shape of flow passages <NUM>, and dimensions of the flow passages <NUM> can be selected to achieve the desired total flow area. For example, as the number of flow passages <NUM> increases, the dimensions of each respective flow passage <NUM> can decrease such that the total flow area between the exterior of the distal end portion and the annular space is between about <NUM> in<NUM> and <NUM> in<NUM>.

With reference to <FIG>, the steering mechanism described above having a plurality of cables <NUM> extending a length of the guide catheter <NUM> can be seen within the sidewall of the guide catheter <NUM>. As described above, applying tension to cables <NUM> can cause the distal end portion of guide catheter <NUM> to bend or curve in direction X within reference plane P. For purpose of example and not limitation, each flow channel <NUM> can be offset circumferentially about the perimeter of the distal end port <NUM> from the reference plane P. As embodied herein, each flow channel can be offset circumferentially by about <NUM> degrees from the reference plane P. The circumferential offset of the flow channels <NUM> can help maintain adequate flow area in the annular space during insertion and manipulation of the delivery system.

The flow passages <NUM>, including flow channels <NUM>, can be formed or incorporated into the wall of the guide catheter <NUM>, such as by extrusion, or can be a separate layer positioned within the guide catheter <NUM>. Furthermore, the flow passages <NUM> can extend the entire length of the guide catheter <NUM> or can extend along one or more portions of the length of the catheter. For purpose of example and as embodied herein, the flow passages <NUM> can extend along a length of the distal end portion of the guide catheter.

With reference to <FIG>, the distal end <NUM> of the guide catheter <NUM> can be tapered. As embodied in the claimed invention, the distal end <NUM> includes a distal tip member <NUM> having the distal end port <NUM> and flow channels <NUM> defined therein. As embodied herein, the flow channels <NUM> can run the length of the distal tip member <NUM>. Additionally or alternatively, the flow channels <NUM> can extend any suitable length from the exterior of the distal end portion <NUM> proximally along the length of the distal end portion and/or along at least a portion of the intermediate length of the guide catheter <NUM>. The length and location of the flow channels <NUM> along the length of the guide catheter can be selected to maintain sufficient flow area in communication with the annular space along the length of the guide catheter <NUM>.

The material properties of the distal tip member <NUM> can be selected based on the desired performance characteristics of the distal tip. For purpose of example and not limitation, the distal tip member <NUM> can have a durometer hardness measurement of between about 40D and about 55D or greater. The distal tip can be made of any suitable material, including polyurethane, polyester, Pebax, Grilamid TR55, and AESNO, or various composite materials used in the construction of catheters. For purpose of example, and as embodied herein, the distal tip can be made of Pebax material having a durometer hardness measurement of 55D.

The material properties, including hardness, of the distal tip member <NUM> and/or distal end <NUM> can be selected to maintain the desired stiffness and other performance characteristics of the distal tip member <NUM> and/or distal end <NUM>. For example, including flow channels in the distal tip member <NUM> can reduce the stiffness of the distal tip member <NUM> as compared to other distal tip members of similar dimensions and construction but without flow channels, as material is removed from the distal tip to define the flow channels therein. A stiffer material having a higher durometer hardness measurement can be used to compensate for the change in stiffness that can be caused by the use of flow channels in the distal tip.

In accordance with another aspect of the disclosed subject matter, and with reference to <FIG>, the plurality of flow passages <NUM> can include a number of flow openings <NUM> defined through a wall of the guide catheter in fluid communication between the exterior of the distal end portion and the annular space. Flow openings <NUM> can be used in addition to, or as an alternative not claimed to, the flow channels described above. For purpose of example, and as embodied herein, the flow openings <NUM> can be generally circular in plan view. The flow openings <NUM> can be defined along a desired length of the guide catheter <NUM>. For example, and as embodied herein, the flow openings can be defined along a length of the guide catheter proximal to the distal tip member <NUM>. As described above, the shape, size, and number of flow openings <NUM> can be selected such that the total flow area between the exterior of the distal end portion and the annular space is between about <NUM> in<NUM> and <NUM> in<NUM>.

Additional examples and details related to delivery devices for directing an interventional device to a targeted treatment area, including steering systems, fixation devices, valves, handles, and deployment mechanisms, are described in <CIT>, <CIT>, <CIT> and <CIT>.

As described above, systems in accordance with the disclosed subject matter can be used in a variety of cardiac procedures, such as a mitral valve replacement, tricuspid valve repair or replacement, chordae tendineae repair or replacement, septal defect repair, occlusion, leaflet modification, leaflet plication, or other cardiac procedure where the monitoring of blood pressure or other hemodynamic properties is desired. <FIG> illustrates a transfemoral approach using a delivery system <NUM> in a procedure requiring access to the left side of the heart, such as a mitral valve repair or replacement procedure. As shown, an interventional device <NUM> is delivered through the femoral vein by passing an inner shaft <NUM>, to which the interventional device <NUM> is coupled, through a guide catheter <NUM> and a sleeve <NUM>. The interventional device <NUM> is passed through the inferior vena cava <NUM>, into the right atrium <NUM>, through the inter-atrial septum <NUM> via a puncture, and into the left atrium <NUM>. When necessary or desired, the interventional device <NUM> can then be directed across the mitral annulus <NUM> and into the left ventricle <NUM> via translation of the inner shaft <NUM>. As shown, the steering functionality of the guide catheter <NUM> and/or sleeve <NUM>, combined with the translatability of the sleeve <NUM> through the guide catheter <NUM> and the translatability of the inner shaft <NUM> through the sleeve <NUM>, enables positioning of the interventional device <NUM> at the targeted treatment area.

<FIG> illustrates an embodiment of a fixation device that can be adapted for use in systems in accordance with the disclosed subject matter. The fixation device, or clip, <NUM> includes a coupling member <NUM> and a pair of opposed distal elements <NUM>, the distal elements <NUM> being formed as elongate arms rotatably connected to the coupling member <NUM>. The engagement surfaces <NUM> of the distal elements <NUM> have a cupped or concave shape to surface area in contact with tissue and to assist in grasping and holding valve leaflets when deployed.

In an embodiment suitable for mitral valve repair, the transverse width across engagement surfaces <NUM> (which determines the width of tissue engaged) is at least about <NUM>, usually <NUM>-<NUM>, and preferably about <NUM>-<NUM>. The distal elements <NUM> are configured to engage a length of tissue of about <NUM>-<NUM>, and preferably about <NUM>-<NUM> along the longitudinal axis of the distal elements <NUM>. The distal elements <NUM> can include a plurality of openings to enhance grip and to promote tissue ingrowth following implantation.

When deployed, valve leaflets are grasped between the distal elements <NUM> and a set of proximal elements <NUM>, which are resiliently cantilevered from coupling member <NUM>. The proximal elements <NUM> are resiliently biased toward the distal elements <NUM>. Each of the proximal elements <NUM> is shaped and positioned to be at least partially recessed within the concavity of the corresponding distal element <NUM> when no tissue is present. The proximal elements <NUM> include a plurality of openings <NUM> and scalloped side edges <NUM> to increase grip on tissue.

The clip <NUM> also includes an actuation mechanism <NUM> formed from two linking legs each rotatably joined with one of the distal elements <NUM> and rotatably joined at an opposite end to a stud <NUM>. As the stud <NUM> is moved axially, the legs of the actuation mechanism <NUM> are rotated, which also rotates the distal elements <NUM> between closed, open and inverted positions. Likewise, immobilization of the stud <NUM> holds the legs of the actuation mechanism <NUM> in place to lock the distal elements <NUM> in a desired position.

In the open position, the clip <NUM> can engage the tissue to be approximated. During deployment in a mitral valve repair procedure, the distal elements <NUM> are oriented to be perpendicular to the line of coaptation, and are then positioned so that the engagement surfaces <NUM> contact the ventricular surface of the valve leaflets. The proximal elements <NUM> remain on the atrial side of the valve leaflets so that the leaflets can be grasped between the proximal elements <NUM> and distal elements <NUM>. Once the clip <NUM> has been properly positioned, the proximal elements <NUM> are lowered toward the engagement surfaces <NUM> (e.g., by releasing tension on attached control lines) so that the leaflets are held therebetween.

After the leaflets have been captured between the proximal elements <NUM> and distal elements <NUM> in a desired arrangement, the distal elements <NUM> can be rotatably moved toward a closed position, and the clip <NUM> can be decoupled from a shaft and/or any other delivery mechanisms. Embodiments of tissue fixation clips are further described in <CIT> and <CIT>.

Systems of the disclosed subject matter have demonstrated desired performance characteristics, including adequate configuration and flow area of the annular space such that pressure waves originating exterior of the distal end portion of the guide catheter can be transmitted through the annular space along the length of the guide catheter and can be monitored by the pressure sensor proximate the proximal end of the guide catheter. For purpose of understanding and not limitation, data is provided to demonstrate various operational characteristics achieved by the systems disclosed herein. For purpose of understanding, laboratory measurements were collected to demonstrate the performance of systems in accordance with the disclosed subject matter under laboratory conditions, as described below.

<FIG> depicts dimensions of the delivery systems tested. The Lo test group included <NUM> systems with the dimensions shown. The inner diameter <NUM> of the distal end port, or "Soft Tip ID," was measured as <NUM> inches for the five Lo samples tested. The "Channel to Channel" dimension <NUM> was measured as <NUM> inches for the five Lo samples tested, which corresponds with a flow channel depth of <NUM> inches. The flow channel width <NUM> was measured as <NUM> inches for the five Lo samples tested.

Likewise, the inner diameter <NUM> of the distal end port, or "Soft Tip ID," was measured as <NUM> inches for the five Nominal samples tested. The "Channel to Channel" dimension <NUM> was measured as <NUM> inches for the five Nominal samples tested, which corresponds with a flow channel depth of <NUM> inches. The flow channel width <NUM> was measured as <NUM> inches for the five Nominal samples tested.

The flow channels <NUM> were offset circumferentially by about <NUM> degrees from the guide catheter bend reference plane for each of the samples tested in both the Nominal and Lo groups.

A <NUM> Fr reference catheter was tested with each test unit as a control. Reference catheters were inspected before use. If kinked or damaged, a new catheter was used. 5Fr diagnostic catheters are an acceptable control per current industry standards for invasive left atrial hemodynamic monitoring.

Five sample units per group were tested under three test conditions, simulating <NUM> BPM, <NUM> BPM, and <NUM> BPM, respectively. Thus, each test group included a total of <NUM> data points used for statistical analysis. Tolerance interval analysis was used, and the one-sided upper tolerance limit was calculated and compared to an acceptance limit. The use of a tolerance interval (also referred to as a confidence and reliability interval) is a conservative choice for a coverage interval compared to a confidence interval. This is because it makes an inference on the proportion of individual values within the population at a specified confidence level, as opposed to making an inference on just the location of the average value.

Data outputs from the testing include pressure profiles from the <NUM> Fr reference catheter and the tested guide catheter across five cardiac cycles for each test configuration /condition. Descriptive statistics (i.e. mean ± standard deviation of the waveform maximum, mean, and minimum) from the average of the five cardiac cycles was calculated for both the reference catheter and tested guide catheter. Max, Mean, and Min values can be clinically relevant values for assessment. The minimum value can be used to ensure the overall amplitude of the waveform is not dampened.

Test Model: With reference to <FIG>, the atrial pressure testing model is comprised of three main components: a preload chamber, rigid atrial chamber, and pulsatile pump. The pre-load chamber serves as a fluid reservoir to passively fill the simulated atrium (LA) of heart and most importantly simulates pre-load pressures into LA from pulmonary flow. The rigid atrial chamber is <NUM>-D printed to include several access points for secure entry of SGC device, reference catheter and endoscope. the atrium is connected to a pulsatile pump, which controls the stroke volume, flow rate, and output phase ratio.

To ensure the test model produced waveforms appropriate for assessment of LAP monitoring devices, pressure waveforms from the model were compared to human LAP waveforms. Waveforms were downloaded Fast Fourier transform (FFT) analysis was conducted to break down the pressure signals, as a function of time, into the frequency domain such that the two signals could be compared in a similar format. The analysis resulted in the model producing waveforms of equal frequency to clinical data; therefore, the afore described model is appropriate for use.

Results: Under all test conditions, the LAP (max, mean, and min values) measured by the Nominal and Lo samples are < <NUM> mmHg of the LAP measured by the reference catheter.

With reference to <FIG>, the results of the Shapiro-Wilk W test show the P-values for SGC07-Nominal max, mean, and min groups are <NUM>, <NUM>, and <NUM>, respectively. Since the P values are ≥ <NUM>, there is insufficient evidence to reject the assumption that the data were drawn from a normal distribution. Therefore, it is acceptable compare the one-sided upper tolerance limit at <NUM>/<NUM> confidence and reliability to the acceptance limit of <NUM> mmHg. All calculated upper tolerance limits are less than <NUM> mmHg.

With reference to <FIG>, the results of the Shapiro-Wilk W test show the P-values for SGC07-Low max, mean, and min groups are <NUM>, <NUM>, and <NUM>, respectively. Since the P values are ≥ <NUM>, there is insufficient evidence to reject the assumption that the data were drawn from a normal distribution. Therefore, it is acceptable compare the one-sided upper tolerance limit at <NUM>/<NUM> confidence and reliability to the acceptance limit of <NUM> mmHg. All calculated upper tolerance limits are less than <NUM> mmHg.

Accordingly, systems according to the disclosed subject matter demonstrated adequate configuration and size to enable pressure monitoring capability as compared to a 5Fr reference catheter under the laboratory test conditions described above.

In addition to the specific embodiments claimed below, the disclosed subject matter is also directed to other embodiments having any other possible combination of the dependent features claimed below and those disclosed above. As such, the particular features presented in the dependent claims and disclosed above can be combined with each other in other manners within the scope of the disclosed subject matter such that the disclosed subject matter should be recognized as also specifically directed to other embodiments having any other possible combinations. Thus, the foregoing description of specific embodiments of the disclosed subject matter has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosed subject matter to those embodiments disclosed.

Claim 1:
A delivery system (<NUM>) for a fixation device, comprising:
a guide catheter (<NUM>) comprising a proximal end portion (<NUM>) having a proximal end port (<NUM>), a distal end portion (<NUM>) having a distal end port (<NUM>), and an inner surface defining an inner lumen (<NUM>) extending in fluid communication between the proximal end port and the distal end port;
a delivery catheter (<NUM>) extending through the inner lumen (<NUM>) of the guide catheter (<NUM>) to define an annular space (<NUM>) between an outer surface (<NUM>) of the delivery catheter (<NUM>) and the inner surface (<NUM>) of the guide catheter (<NUM>); and
a pressure sensor (<NUM>) proximate the proximal end portion (<NUM>) of the guide catheter (<NUM>) in fluid communication with the annular space (<NUM>) to monitor fluid pressure within the annular space (<NUM>),
wherein the distal end portion (<NUM>) of the guide catheter includes a distal tip member (<NUM>) having the distal end port (<NUM>) defined therein; the system is characterized in that the distal tip member (<NUM>) comprises a plurality flow passages (<NUM>) in fluid communication between an exterior of the distal end portion (<NUM>) of the guide catheter (<NUM>) and the annular space(<NUM>), the plurality of flow passages (<NUM>) comprising a number of flow channels (<NUM>) defined in the distal tip member (<NUM>) and spaced about a perimeter of the distal end port (<NUM>).