Pressure sensing guidewires, and systems and methods for structural heart procedures

Abstract

To provide structural heart guidewires for enabling a cardiovascular specialist to improve structural heart procedures.SOLUTION: A pressure guidewire is provided that includes an outer tube, a connector tube positioned radially inward of the outer tube, a pressure sensor assembly, and / or a distal tip at the distal end of the outer tube. A core wire may be positioned distal to the connector tube. The core wire may have a reduced diameter portion such as a tapered portion. The pressure sensor assembly may include a pressure sensor positioned distal to the connector tube, e.g., radially between a coil portion of the outer tube and the core wire. The pressure sensor assembly may also include one or more pressure wires leads extending from the pressure sensor through the connector tube lumen.SELECTED DRAWING: Figure 2A

Description

Technical Field

[0001] Incorporation by reference to priority applications This application claims the benefit of U.S. Provisional Patent Application No. 62 / 849,768, filed May 17, 2019, and U.S. Provisional Patent Application No. 62 / 926,737, filed October 28, 2019, and all of those patent applications are hereby incorporated by reference in their entirety herein.

[0002] Any and all applications in which foreign or domestic priority claims are identified in the application data sheet filed herewith are hereby incorporated by reference herein under 37 C.F.R. § 1.57.

[0003] This application is directed to a structural heart guidewire configured to sense blood pressure to provide information about blood flow through a heart valve before, during, and / or immediately after a structural heart procedure.

Background Art

[0004] Guidewires are known for delivering catheters to many vascular sites in the body. Access to the vascular site is facilitated by a combination of mechanical properties such as flexibility, pushability, and torqueability. It is known that coronary artery procedures include pressure sensors to enable measurement of blood flow through a static occlusion to assist a cardiologist in determining whether to treat a patient.

[0005] Pressure sensing around static obstructions in the coronary vasculature is known, but such concepts have not been applied to structural heart procedures such as for the treatment of heart valves and for improving the pumping function of the heart. The pumping function has been addressed with various types of mechanical pumps. Heart valves have historically been treated by open heart surgery. However, currently, heart valves are increasingly being replaced by cardiologists using percutaneous heart valves and catheters through which such valves are delivered.

Summary of the Invention

Problems to be Solved by the Invention

[0006] Coronary guidewires for measuring pressure have been described and commercially available for many years, but structural heart guidewires have not been developed. Therefore, there is a need for a structural heart guidewire to enable cardiologists to improve structural heart procedures.

Means for Solving the Problems

[0007] During structural heart procedures, the downstream pressure curve and the upstream pressure curve can be used to determine the state of the heart valve and the situation of blood flow through the heart valve, and in some cases, to determine how and when to treat the patient. Depending on the valve and technique being treated, in some embodiments, the downstream pressure curve can be provided by a pressure sensor in the guiding catheter, a pressure guidewire, or other device capable of sensing pressure. The upstream pressure curve can be provided by a pressure guidewire or other device capable of sensing the pressure upstream of the downstream pressure measurement. In other embodiments, the upstream pressure curve can be provided by a guiding catheter pressure sensor, a pressure guidewire, or other device capable of sensing pressure. The downstream pressure curve can be provided by a pressure guidewire or other device capable of sensing the pressure downstream of the upstream pressure measurement.

[0008] For example, some methods for evaluating a heart valve include accessing the patient's blood flow path at an access location. The access location can be the femoral artery, radial artery, femoral vein, radial vein, left ventricular apex, or other locations. A pressure guide wire can be advanced through the access location to a location adjacent to the patient's treatment site, such as, for example, a heart valve to be evaluated, treated, or replaced. A pressure sensing device separate from the pressure guide wire can be advanced to the opposite side of the treatment site, such as, for example, to the side of the heart valve opposite the side of the valve, where a pressure sensing device is positioned toward the distal tip of the pressure guide wire. The pressure sensing device can comprise, or be disposed in, a pigtail catheter of the aorta, a guiding catheter, a pressure guide wire, or other devices capable of sensing pressure. A treatment device, such as a balloon or replacement heart valve, can be advanced over the pressure guide wire. In some implementations, the pressure sensing device can sense pressure on a first side of the heart valve, such as, for example, in the aorta or atrium, and the pressure guide wire can sense pressure on a second side of the heart valve, such as, for example, in the left ventricle or right ventricle. In some implementations, the pressure sensing device can sense pressure in a heart chamber, and the pressure guide wire can sense pressure in the opposite blood flow path of the heart valve, such as, for example, in a second heart chamber or the aorta. Specific examples include positioning a pressure sensing device in the left ventricle to sense pressure in the left ventricle and positioning the pressure guide wire in the aorta to sense pressure in the aorta and evaluate the aortic valve from a transapical approach to access the heart. Another specific example includes positioning a pressure sensing device in the left ventricle to sense pressure in the left ventricle and positioning the pressure guide wire in the left atrium to sense pressure in the left atrium and evaluate the mitral valve from a transapical approach to access the heart. The pressure measurements can be used to measure the condition of the valve, such as the pressure gradient across the heart valve and / or valve regurgitation.

[0009] The methods described herein may include steps for equalizing pressure measurements between a pressure sensing device and a pressure guide wire. Equalization of pressure can be performed anywhere, such as in the aorta or left ventricle. The step of equalizing pressure measurements may include automatically or manually adjusting the phase delay between a pressure curve generated from the pressure sensing device and a pressure curve generated from the pressure guide wire.

[0010] Some of the methods described herein are directed to addressing and / or treating cardiac and / or cardiovascular conditions. In some cases, the method includes treating a structural cardiac condition. For example, the method may include accessing the patient's blood flow path at an access location, advancing an access catheter through the access location to a location in the heart, advancing a pressure guide wire through the access catheter, and / or sensing pressure using the pressure guide wire. The method may also include inducing high-frequency pacing through the pressure guide wire. For example, current may be sent from the proximal segment of the pressure guide wire through the core wire of the pressure guide wire to the distal segment of the pressure guide wire. The access catheter or other delivery catheter can insulate the patient from the current in the pressure guide wire for high-frequency pacing. In some configurations, the pressure guide wire may include an insulator along at least a portion of the pressure guide wire. For example, a polymer layer such as a PTFE layer can insulate the patient from the pressure guide wire for high-frequency pacing when application of current is not desired. By combining pressure sensing with the ability for high-frequency pacing, these methods eliminate the need for a separate pacing device and / or the need to exchange such a device for continuous application of these capabilities.

[0011] A variety of pressure guide wire configurations are suitable for the pressure sensing methods described herein. These pressure guide wires can guide other catheters that are advanced over the pressure guide wire. The distal segment of the catheter may include a curvature to provide a non-traumatic tip. The pressure guide wire may include a distal tip for surrounding the distal end of the pressure guide wire, for example, to prevent fluid flow or structural passage through the distal end of the pressure guide wire.

[0012] For example, the guide wire may include a connector tube and a core wire extending distally from the distal end of the connector tube. The guide wire may include a sensor assembly having a sensor (e.g., a pressure sensor) and a sensor housing positioned over the sensor. An insulating portion may cover at least a portion of the connector tube and may extend proximally to the sensor housing. The connector tube and / or the core wire may have a uniform diameter or may have a reduced diameter portion, such as a tapered portion. Optionally, the guide wire may include a distal tip at the distal end of the guide wire.

[0013] In some configurations, a coil portion may at least partially surround the core wire. The insulating portion and the coil portion may have the same outer diameter.

[0014] In some configurations, at least one (e.g., one, two, three, or more) conductive regions of the connector tube may be exposed from the insulating portion. At least one conductive region may be positioned external to the patient during the procedure. At least one conductive region may include spaced apart first and second conductive regions. For example, the first conductive region may be positioned at the proximal end of the guide wire and the second conductive region may be positioned distally of the first conductive region.

[0015] Some of the pressure guidewires described herein may include an outer tube having a lumen extending therethrough. At least a portion of the outer tube includes a coil portion and / or a connector tube. The pressure guidewire may also include a core wire extending through at least a portion of the lumen of the outer tube. In some configurations, the core wire may extend for substantially the entire length or the entire length of the lumen of the outer tube. The core wire may include a reduced diameter portion, such as a tapered portion. The pressure guidewire may also include a pressure sensor assembly having a pressure sensor and one or more pressure wire leads extending from the pressure sensor toward the proximal end of the pressure guidewire. For example, the pressure sensor may be an optical sensor, an electrical sensor, a MEMS sensor, or a membrane-based sensor, and the pressure wire leads may be optical fibers or electrical wires. The pressure sensor may be positioned radially between the reduced diameter portion of the core wire and the coil portion of the outer tube. The pressure sensor may be disposed within a sensor housing, or the outer tube itself may provide the sensor housing. The pressure sensor may be exposed to the blood flow outside the pressure guidewire through the space in the coil portion and / or through one or more openings in the sensor housing, or may be in pressure communication with the blood flow outside the pressure guidewire.

[0016] At least a portion of at least one pressure wire lead may not be concentric with the outer tube. For example, a first region of the pressure wire lead may be concentric with the outer tube, and a second region of the pressure wire lead may be non - coaxial with the longitudinal axis of the outer tube. The second region may be positioned radially outside the core wire. For example, in the distal region of a pressure guide wire where the core wire has a reduced diameter, there may be a space between the core wire and the outer tube to position the pressure sensor non - coaxially with respect to the longitudinal axis of the outer tube. When the pressure sensor is positioned in the distal region of the pressure guide wire, the pressure guide wire can measure pressure at a position that is more centrally located in the heart cavity, while the core wire maintains structural integrity in the distal region. However, it may be beneficial for at least a portion of the pressure wire lead to be concentric with the outer tube to facilitate connection to an optical connector or other connector at the proximal end of the pressure guide wire.

[0017] The outer tube may comprise an opening configured to allow at least one pressure wire lead to transition from a first region that is concentric with the outer tube to a second region that is not concentric with the outer tube. The opening may be a cut - out partial thickness or may extend through the entire thickness of the outer tube. If the opening extends through the entire thickness of the outer tube, the opening may be sealed, for example, using an adhesive, to prevent fluid from flowing through the opening to the pressure guide wire.

[0018] In some implementations, to induce high-frequency pacing, current can be sent through the core wire to a conductive surface outside the guide wire. When the core wire extends substantially or entirely along the working length of the pressure guide wire, the current generator can send the current directly to the core wire or to an exposed conductor that is in direct or indirect contact with the proximal portion of the core wire. Additionally or alternatively, the current can be sent to a conductive tube and / or coil and then transmitted directly or indirectly to the core wire, for example, through another conductive connector. In some configurations, the outer tube of the pressure guide wire may include an insulator, such as a polymer layer like PTFE, along at least a portion of the pressure guide wire to insulate the patient from the core wire.

[0019] Some portions of the pressure guide wire described herein include a connector tube, a core wire, a coil portion, and / or a pressure sensor assembly. The connector tube can extend from the proximal end of the pressure guide wire such that a current generator can be coupled to the connector tube. The core wire can extend distally beyond the distal end of the connector tube, for example, through the distal end of the connector tube, or can extend distally beyond the distal end of the connector tube. The core wire may include a reduced-diameter portion, such as a tapered portion. In some implementations, current can be sent directly or indirectly from the connector tube to the core wire for high-frequency pacing. For example, when using optical sensing, the current can be sent from the connector tube to the core wire through a connector separate from the connector for the optical connection.

[0020] The coil portion can be positioned distally beyond the distal end of the connector tube and can surround at least a portion of the core wire. The coil portion may include a sensor housing region that is more rigid than other regions or the remainder of the coil portion, such as a tube or weld. The pressure sensor of the pressure sensor assembly can be disposed within the sensor housing region of the coil portion. In this configuration, the sensor housing region of the coil portion can include one or more apertures to allow blood or other fluid in pressure communication with the blood to reach the pressure sensor.

[0021] The pressure sensor assembly can include a pressure sensor and one or more pressure wire leads extending from the pressure sensor toward the proximal end of the pressure guide wire. For example, the pressure sensor can be an optical sensor, an electrical sensor, a MEMS sensor, or a membrane-based sensor. The pressure sensor can be positioned radially between the reduced-diameter portion of the core wire and the coil portion such that fluid can flow through the space in the coil portion to the pressure sensor. In some configurations, the pressure sensor assembly may include another pressure housing disposed over the pressure sensor.

[0022] The pressure wire leads can be optical fibers or electrical wires. A first region of at least one pressure wire lead can be concentric with the connector tube, and a second region of the pressure wire lead can be non-concentric with the longitudinal axis of the connector tube. The second region of the pressure wire lead can be positioned radially outside the core wire. The wall of the connector tube can include an opening such that the pressure wire lead can transition from a first region that is concentric with the connector tube to a second region that is non-concentric with the longitudinal axis of the connector tube. The opening can be a cut-away partial thickness or can extend through the entire thickness of the connector tube. If the opening extends through the entire thickness of the connector tube, the opening can be sealed to prevent fluid from flowing through the opening to the pressure guide wire. In other configurations, the pressure guide wire can include another connector with an opening such that the pressure wire lead can transition from a first region that is concentric with the connector tube to a second region that is non-concentric with the longitudinal axis of the connector tube.

[0023] Some of the pressure guidewires contemplated herein include an outer tube, a connector tube positioned radially inward of the outer tube, a pressure sensor assembly, and / or a distal tip at the distal end of the outer tube. The outer tube may have a uniform or substantially uniform diameter. A core wire may be positioned distally of the connector tube. The core wire may have a reduced diameter portion, such as a tapered portion. The pressure sensor assembly may include a pressure sensor positioned distally of the connector tube, for example, radially between a coil portion of the outer tube and the core wire. The pressure sensor assembly may also include one or more pressure wire leads extending from the pressure sensor through the lumen of the connector tube.

[0024] The pressure guidewire may include a sensor housing, for example, in the outer tube or over the pressure sensor but within the outer tube. The sensor housing may include at least one opening to allow blood or other fluid to flow to the pressure sensor. In this configuration, the pressure guidewire may include a second coil portion extending proximally from the sensor housing towards the proximal end of the pressure guidewire. The coil portion of the outer tube may extend along most of the working length of the pressure guidewire or along substantially the entire working length of the pressure guidewire. The proximal end of the connector tube may be exposed from the proximal end of the second coil portion to facilitate high-frequency pacing. For example, less than 10 percent or less than 5 percent of the length of the connector tube may be exposed from the proximal end of the second coil portion.

[0025] These and other features, aspects, and advantages are described below with reference to the drawings, which are intended for purposes of illustration only and should not be construed as limiting the scope of the embodiments. Further, the various features of the different disclosed embodiments may be combined to form additional embodiments, which are part of this disclosure. In the drawings, like reference numerals consistently refer to corresponding features throughout the similar embodiments. The following is a brief description of each of the drawings.

Brief Description of the Drawings

[0026]

Fig. 1A

Fig. 1B

Fig. 1C

Fig. 1D

Fig. 1E

Fig. 1F

Fig. 2A

Fig. 2B

Fig. 2C

Fig. 2D

Fig. 2E

Fig. 2F

Fig. 3

Fig. 4

Fig. 5

Fig. 6

Fig. 7

Fig. 8

Fig. 9

Fig. 10A

Fig. 10B

Fig. 10C

DETAILED DESCRIPTION OF THE INVENTION

[0027] The present application is directed to systems and methods for providing pressure curves during surgical heart procedures, including valve formation procedures, transcatheter aortic valve replacement (TAVR) procedures, also sometimes referred to as transcatheter aortic valve implantation (TAVI) procedures, and transcatheter mitral valve replacement (TAMR) procedures. The systems and methods can be used to assist cardiologists when completing critical aspects of structural heart procedures. Embodiments herein can be used to convey, e.g., graphically, the status of a heart valve to a user interface output before, during, and / or immediately after deployment of a structural heart device such as an aortic valve, mitral valve, or other heart valve. Embodiments herein can be used to convey the nature of blood flow through a heart valve before, during, and / or immediately after deployment of a structural heart device such as an aortic valve, mitral valve, or other heart valve. The novel display device provides an intuitive and / or immediate perception of the patient's condition to streamline the procedure, facilitate the procedure, and increase the success of the procedure.

[0028] The pressure measurements obtained from the systems and methods described herein can be used to calculate indices of heart valves or blood flow, such as an index of valvular regurgitation or a pressure gradient across a native heart valve, a previously placed prosthetic heart valve, or a currently implanted prosthetic heart valve. The indices of valvular regurgitation and pressure gradients enable a cardiologist to properly evaluate the heart valve. During cardiac systole, a larger pressure gradient across the aortic valve (or a lower pressure in the aorta) can indicate greater valvular calcification. A smaller index of regurgitation at the end of diastole can indicate greater regurgitation.

[0029] I. Example Methodology Figures 1A - 1F illustrate various ways of accessing the heart during a structural heart procedure. Either a pressure guidewire 30 or a pressure sensing device (e.g., pigtail catheter 10 or access catheter 20) can be used to calculate an upstream pressure curve (with respect to flow), and the other of the pressure guidewire 30 or pressure sensing device can be used to calculate a downstream pressure curve (with respect to flow). Specific methods are described below with respect to specific heart valves and access techniques, but similar systems may be used to evaluate other valves such as the tricuspid or pulmonary valves.

[0030] Figure 1A shows a system and method for measuring the performance of an existing or replacement aortic heart valve. The existing heart valve can be a native valve with a congenital disease that is accessed in a later procedure, or a previously implanted replacement heart valve. As shown, a pigtail catheter 10 can be positioned downstream of the treatment site, such as downstream of the aortic valve in the aorta A, to provide a downstream pressure curve. The pigtail catheter 10 may be used to deliver a contrast agent to facilitate visualization of the treatment site. An access catheter 20 can be delivered to the heart from the same or a different access site as the pigtail catheter 10. The access catheter 20, or another delivery catheter exchanged with the access catheter 20, can be used to advance a valve inflation balloon, a replacement valve, and / or other devices to the treatment site. A pressure guidewire 30 can extend through the access catheter 20 to a position upstream of the treatment site, such as in the left ventricle LV, for example, to provide an upstream pressure curve. The pressure guidewire 30 can include a pressure sensor 40 at any location along the distal segment of the pressure guidewire 30, such as within a non-invasive bend, at the transition to the non-invasive bend, or proximal to the non-invasive bend (see Figure 2B). Access is provided using an arterial approach, such as a femoral or radial approach, before entering the heart. Figure 1B shows a configuration similar to Figure 1A, except that one or both of the pigtail catheter 10 and / or the access catheter 20 can be used to provide pressure readings using external pressure sensing. The catheter 20 can be capable of measuring the downstream pressure, similar to the pressure read by the pressure guidewire 30. This configuration can be used to equate an external pressure sensor to the pressure guidewire. Alternatively, any other delivery catheter exchanged with the access catheter can be used to provide a downstream pressure curve. In some cases, the output of the downstream pressure can be received by a console that can combine it with the pressure signal of either or both of the pigtail catheter 10 and the access catheter 20.

[0031] It may be important to equalize pressure readings between a downstream pressure sensing device and an upstream pressure sensing device. Equalization may be done in terms of pressure accuracy (gain and offset), or it may be done in terms of phase lag between two pressure curves. For example, pressure readings may be taken from a downstream pressure sensing device and an upstream pressure sensing device in the same general anatomical region, and the pressure measurements may be adjusted manually or automatically for phase lag between the two pressure curves. As shown in FIG. 1B, pressure measurements for equalization may be taken from the left ventricle LV. In this technique, the output of the downstream pressure is provided by the access catheter 20, and the output of the upstream pressure is provided by the pressure guide wire 30. The sensing feature of the access catheter 20 (e.g., the distal end of the column of fluid in catheter 20) is advanced adjacent to the sensing feature of the pressure guide wire 30. The sensing feature of the access catheter 20 and the sensing feature of the pressure guide wire 30 may be secured to be disposed in the left ventricle LV. The sensing feature of the access catheter 20 and the sensing feature of the pressure guide wire 30 may be secured to be in similar positions in the left ventricle LV.

[0032] FIG. 1C shows a configuration similar to FIG. 1A, except that the pressure sensor 40 is positioned proximal to the non-invasive bend of the pressure guide wire 30. For example, the sensing feature of the pigtail catheter 10 (e.g., the distal end of the column of fluid in catheter 10) is advanced adjacent to the sensing feature of the pressure guide wire 30. The sensing feature of the pigtail catheter 10 and the sensing feature of the pressure guide wire 30 may be secured to be disposed in the aorta A. In this configuration, pressure equalization may be performed in the aorta A. After pressure equalization, the pressure guide wire 30 may be advanced to the left ventricle LV to provide the upstream pressure curve, while the pigtail catheter 10 remains in the aorta A to provide the downstream pressure curve.

[0033] In FIG. 1D, the pigtail catheter 10 can be positioned in the aorta A to provide a downstream pressure curve. The pressure guide wire 30 extends through the pigtail catheter 10 in this embodiment to provide an upstream pressure curve. In this configuration, pressure equalization can be performed in the aorta A. For example, the sensing feature of the pressure guide wire 30 can be advanced to the end of the fluid column in the pigtail catheter 10, or immediately distal to that end. The signal from the sensing feature of the pressure guide wire 30 and the fluid column can be compared to equalize them. After pressure equalization, the pressure guide wire 30 can be withdrawn from the aortic pigtail as is normally done and inserted into the left ventricle via an access catheter, while the pigtail catheter 10 remains in the aorta A to provide a downstream pressure curve.

[0034] The systems described herein may be used to measure the performance of existing or replacement mitral valves. For example, as shown in FIG. 1E, the access catheter 20 can be advanced to the right atrium RA through the venous vasculature, such as from a femoral approach, through the inferior or superior vena cava VC. Next, the access catheter 20 can be advanced through the atrial septum to a position in the left atrium LA. In some variations, the access catheter 20 can be configured to provide access through the patient's foramen ovale, or to track a guide wire or device that provides such access. The access catheter 20, or another delivery catheter exchanged for the access catheter 20, can be used to advance a valve inflation balloon, replacement valve, and / or other devices to the treatment site. The pressure guide wire 30 may extend through the access catheter 20 into the left ventricle LV. The access catheter 20 can provide a pressure signal that can be used to generate an upstream pressure curve, while the pressure guide wire 30 provides a pressure signal that can be used to generate a downstream pressure curve. Alternatively, any other delivery catheter exchanged for the access catheter may be used to provide an upstream pressure curve.

[0035] A similar system may be used in an apical approach for the treatment of the aorta or mitral valve. For example, as shown in FIG. 1F, an access catheter 20 can access the left ventricle LV through the apex P of the heart. Another device (not shown) can be used to create a path through the apex P. The access catheter 20 can be advanced through a device or the like. The access catheter 20, or another delivery catheter exchanged with the access catheter 20, can be used to advance a valve inflation balloon, replacement valve, and / or other device to the treatment site. A pressure guide wire 30 can extend through the access catheter 20 to the aorta A in the treatment of the aortic valve. The access catheter 20 can provide a pressure signal that can be used to calculate an upstream pressure curve, while the pressure guide wire 30 can provide a signal that can be used to calculate a downstream pressure curve. Alternatively, any other delivery catheter exchanged with the access catheter may be used to provide the upstream pressure curve.

[0036] FIG. 1F shows the evaluation or treatment of the aortic valve through the apex P of the heart, but the pressure guide wire 30 can be advanced through the mitral valve M such that its sensing feature is in the left atrium. In this method, the pressure guide wire can provide a pressure signal that can be used to calculate a left atrial pressure curve (from the perspective of flow, a proximal or upstream pressure curve). The access catheter 20 can generate a pressure signal that can be used to calculate a left ventricular pressure curve (from the perspective of flow, a distal or downstream pressure curve).

[0037] During a valve inflation procedure, sometimes called a valvuloplasty or valve implantation procedure, native circulation through the heart valve can be obstructed by a valvuloplasty balloon, valve replacement delivery system, or other treatment device. However, when the heart is pumping, pressure from the left ventricle LV or myocardial compression can drive the treatment device back towards the aorta A, making it difficult to properly position the treatment device. High frequency pacing, or defibrillating the left ventricle LV, can also reduce the pressure gradient between the aorta A and the left ventricle LV, reduce myocardial force, and allow the clinician to complete the procedure. Conventional high frequency pacing can involve introducing a temporary pacemaker into the heart, which typically requires another access location, such as a venous access location. A temporary pacemaker can also burn the heart and cause other complications. Instead, a pressure guidewire 30 may be used to perform high frequency pacing. As previously explained, the pressure guidewire 30 can be introduced through the same access location as the access catheter 20 or other delivery device, which reduces the overall number of access locations. Current can be sent to the proximal section of the pressure guidewire and transmitted to the distal section of the pressure guidewire via a connector tube and / or core wire, as will be explained in more detail later. The access catheter 20 or other delivery catheter can insulate at least the middle section of the pressure guidewire for high frequency pacing from the patient to prevent burning. Alternatively or additionally, the pressure guidewire 30 may include an insulating portion to isolate the pressure guidewire 30. As shown in Figure 2B, the distal section of the pressure guidewire can include a curvature that contacts current at multiple locations on the ventricular wall.

[0038] II. Overview of the Pressure Wire System and Its Use Figure 2A shows a diagnostic system 200 that can be used in a patient's vasculature. The diagnostic system 200 is configured to determine whether the degree of valve damage indicates the severity such that balloon inflation (e.g., valvuloplasty), valve replacement, or other catheter intervention should be performed.

[0039] Diagnostic system 200 may include a monitor assembly 204 configured to be coupled to a pressure guide wire 208. Diagnostic system 200 may include a connection portion (indicated by the dotted line) that facilitates connection of the monitor assembly 204 to the pressure guide wire 208 and disconnection of the pressure guide wire 208 from the monitor assembly 204. Connecting to and disconnecting from the monitor assembly 204 is useful when allowing a clinician to initially use the pressure guide wire 208 to evaluate the effects of heart valve damage. The pressure guide wire 208 may be used to deliver a treatment device such as a balloon catheter or a valve delivery system.

[0040] An optical fiber interface cable 202 may be used to couple the pressure guide wire 208 to the monitor assembly 204 using a handle 207. In some embodiments, system 200 receives an input from a tubular catheter body used to access the vasculature. For example, access catheter 20 may be an access catheter. The pressure sensing distal tip of access catheter 20, or the pressure sensing distal tip in access catheter 20, may be positioned adjacent to the treatment site such that a pressure signal corresponding to the pressure on the first side of the treatment site, such as in the aorta, is obtained. This pressure measurement may also be referred to herein as Pa. In other configurations, system 200 may include a pressure sensing device such as a pigtail catheter that is delivered separately from the pressure guide wire to obtain Pa.

[0041] The pressure guide wire 208 can take any suitable form. For example, the pressure guide wire 208 can include a proximal segment having a proximal end positioned outside the patient and a distal end that can be advanced into the vasculature through the access catheter 20. The pressure guide wire 208 can be configured to be flexible to pass through a tortuous vasculature while maintaining structural integrity for pushability and torqueability. For example, at least the proximal region of the pressure guide wire 208 can be supported by a connector tube and / or a core for structural integrity, while the distal region of the pressure guide wire 208 can be formed to provide greater flexibility and include a non-invasive bend 250, such as the coiled tip shown in FIG. 2B, to prevent puncture. In other configurations, a curved distal region may be coupled to the pressure guide wire 208 to provide the non-invasive bend 250.

[0042] Any sensing modality can be used. For example, an optical sensor can be configured to sense pressure when exposed to blood. The optical sensor can be disposed within the internal space of the pressure guide wire 208 that is in fluid communication with the exterior of the pressure guide wire 208. The sensor can be an optical or electrical pressure sensor. The sensor can be selectively disposed in communication with the monitor assembly 204 by a pressure wire lead disposed between the sensor and the proximal end of the pressure guide wire 208. The pressure wire lead can be an optical fiber or an electrical wire.

[0043] As shown in FIG. 2B, the pressure sensor can be positioned at any location along the distal region of the pressure guide wire 208. For example, the pressure sensor can be near the most distal tip of the guide wire at location 206D, along the curvature 250 of the guide wire at location 206C, at the transition to the curvature 250 of the guide wire at location 206B, or proximal to the curvature 250 of the guide wire at location 206A. For example, location 206C may be approximately 270 degrees around the curvature 250 from the straight region of the pressure guide wire (around location 206A), and location 206D may be approximately 540 degrees around the curvature from the straight region of the pressure guide wire. However, the pressure sensor can be positioned at any location in the curved distal region of the pressure guide wire, such as between, for example, about 0 degrees and about 90 degrees, between about 90 degrees and about 180 degrees, between about 180 degrees and about 270 degrees, between about 270 degrees and about 360 degrees, between about 360 degrees and about 450 degrees, or between about 450 degrees and about 540 degrees, inclusive, from the straight region of the pressure guide wire.

[0044] When the distal region is rounded, the pressure sensor can be positioned approximately 270 degrees along the curved portion 250 from the straight region of the pressure guide wire 208. The location of the pressure sensor within the distal region of the guide wire can affect the accuracy of pressure measurement. For example, when the pressure sensor is at more distal locations 206C, 206D, the pressure sensor can be positioned more centrally within a chamber of the heart, such as the left ventricle LV, and displaced from the chamber wall. Also, at the more distal locations 206C, 206D, the pressure sensor is less likely to be obstructed by an access catheter or other delivery catheter during valve formation or heart replacement procedures. At the more proximal locations 206A, 206B, pressure measurements are taken closer to the heart valve, and it is possible to perform equalization in the aorta A while maintaining the distal tip of the pressure guide wire 208 within the left ventricle LV. In some procedures, performing equalization in the aorta A requires less manipulation of a pigtail catheter or requires other pressure sensing devices. For example, during aortic valve procedures, a pigtail catheter is already positioned in the aorta. The pressure sensor can be proximal to the curved portion 250, but the pressure sensor is distal enough to take pressure measurements distal to the heart valve. By leaving the distal tip of the pressure guide wire 208 within the left ventricle LV, access to the left ventricle LV is maintained.

[0045] Figure 2C shows a cross-section of the TAVR system in the patient's descending aorta, with biological structures removed for clarity. The TAVR system can be used in connection with a monitor display device 204. For example, a pressure guide wire 208 extends through an access catheter 210. The same access catheter 210 can be used to advance a delivery system 212 over the pressure guide wire 208. The delivery system 212 can be used to advance a valve replacement or other treatment device. Other configurations are possible. For example, a catheter for the access catheter 210 can be exchanged for the delivery system 212 and then advanced over the pressure guide wire 208. As shown, the pressure sensing device used to provide a pressure signal about the pressure of blood in the aorta can be an aortic pigtail catheter 214 that is delivered separately from the access catheter 210 but from the same access location.

[0046] In other configurations, the access catheter 210 or the delivery system 212 can be used to obtain a pressure signal about the pressure of blood in the aorta and thus can be a pressure sensing device for the pressure in the aorta. As shown in Figure 2D, for mitral valve replacement, the access catheter 211 can be a pressure sensing device. A pressure guide wire 208 extends through the access catheter 211 and a delivery system 213 can be advanced over the pressure guide wire 208. The delivery system 213 can be used to deliver a mitral valve or other replacement or treatment device.

[0047] As previously explained, a pressure guide wire can be used to induce a fast heart beat, for example by high frequency pacing. Current can be sent to a biological structure through a conductor in the guide wire, such as through a core wire for example. The pressure guide wire may comprise an insulator, such as a polymer layer like a PTFE layer, along at least a portion of the pressure guide wire, or along a plurality of portions of the pressure guide wire, to insulate the patient from the current. One or more electrically conductive portions of the pressure guide wire (such as a core wire or a conductive connector tube) can be exposed through the insulator such that a pacemaker or other electrical stimulator can be attached to the electrically conductive portion of the pressure guide wire. The one or more exposed portions can be located at any location along the length of the pressure guide wire, for example at the proximal end of the pressure guide wire and / or spaced apart from the proximal end of the pressure guide wire.

[0048] For example, as shown in FIG. 2E, the core wire (or other electrically conductive portion) can expose at least a first conductive region 217a and a second conductive region 217b spaced apart from the first conductive region 217a from the insulator. The first conductive region 217a can be located at the proximal portion of the pressure guide wire or near the proximal portion of the pressure guide wire closer than the distal portion of the pressure guide wire. The second conductive region 217b can be positioned between the distal end of the pressure guide wire and the first conductive region 217a. The pressure guide wire 208 may include a smaller or larger number of exposed conductive regions. When viewed in another way, the pressure guide wire can include at least a first insulator region 234a and a second insulator region 234b spaced apart from the first insulator region 234a. The first insulator region 234a can be positioned at the distal portion of the pressure guide wire or closer to the distal end of the pressure guide wire compared to the proximal end of the pressure guide wire. The second insulator region 234b can extend between the first insulator region 234a and the proximal end of the pressure guide wire. The plurality of exposed conductive regions 217a, 217b provides the physician with the option of connecting the pacemaker 201 near the proximal end of the pressure guide wire (FIG. 2F) or near the distal end of the pressure guide wire (FIG. 2E). One of the exposed conductive regions may be positioned more favorably compared to the other exposed conductive region. For example, when the connection of the pacemaker needs to be placed near the groin, the clinician may desire to connect the pacemaker to the exposed conductive region closer to the distal end of the pressure guide wire. On the other hand, the clinician may prefer to connect the pacemaker to the exposed conductive region closer to the proximal end of the pressure guide wire to avoid as much interference as possible with the delivery system.

[0049] The features of high-frequency pacing described with respect to FIGS. 2E and 2F can be applied to any of the pressure guide wires described herein.

[0050] a. Wire-based pressure guide wire Figures 3 and 4 show different pressure guide wires 308, 408 that can be used in any of the methods described above. The reference numerals used to identify the features of pressure guide wire 308 are increased by a factor of one hundred (100) to identify similar features of pressure guide wire 408. This numbering convention generally applies to the remainder of the figures. Any component of the pressure guide wires described herein is replaceable.

[0051] Generally, pressure guide wires 308, 408 include outer tubes 310, 410 that define a lumen, core wires 316, 416 that extend at least partially through the lumens of outer tubes 310, 410, pressure sensor assemblies 318, 418 disposed within the lumens of outer tubes 310, 410, and / or distal tips 432. Pressure guide wire 308 may also include a distal tip that may be the same or similar to tip 432, or any of the other tips disclosed herein. The outer diameters of pressure guide wires 308, 408 may be uniform or substantially uniform along substantially the entire or the entire working length of pressure guide wires 308, 408. For example, the outer diameter of pressure guide wire 308 may be uniform or substantially uniform along the entire working length, excluding distal tip 432 or non-traumatic bend 250. Pressure guide wires 308, 408 may include an outer diameter of up to 0.035 inches, such as between 0.018 inches and 0.035 inches. In some configurations, the distal portion of pressure guide wires 308, 408 may form a non-traumatic bend 250, such as the coiled portion shown in Figure 2B. In other configurations, the distal portion of pressure guide wires 308, 408 may remain straight from at least the pressure sensor of the pressure sensor assembly to the distal tip of the pressure guide wire.

[0052] FIG. 3 is a schematic view of one variation of the pressure sensing guidewire 308. As shown, at least the distal portion of the outer tube 310 can be coiled. For example, the coil portion 312 can be a flat ribbon-like coil or a round coil. The coil portion 312 can extend along most of the working length of the pressure guidewire 308, substantially along the entire working length of the pressure guidewire 308, or along the entire working length of the pressure guidewire 308. When the substantial length of the outer tube 310 that is coiled, the coil portion 312 provides sufficient flexibility and softness to avoid any trauma (such as perforation and / or incision) during use. The coil portion 312 also promotes safety in the event of distal tip failure. During high-frequency pacing, the coil portion 312 can also ensure electrical contact with the heart.

[0053] As shown in FIG. 3, at least the proximal portion 328 of the core wire 316 can be concentric with the outer tube 310 and can extend through at least a portion of the lumen of the outer tube 310. For example, the core wire 316 can extend along most of the working length of the pressure guidewire 308, substantially along the entire working length of the pressure guidewire 308, or along the entire working length of the pressure guidewire 308. The core wire 316 provides sufficient rigidity to the pressure guidewire 308 for pushability and to prevent entanglement. The core wire 316 also provides sufficient rigidity to support the delivery catheter during valve implantation.

[0054] At least a portion of the core wire 316 may include a reduced-diameter portion 326 to provide space in the lumen of the outer tube 310 for the pressure sensor 322. For example, as shown in FIG. 3, the reduced-diameter portion 326 may be tapered toward the distal end of the pressure guide wire 308. The transition between the proximal portion 328 and the reduced-diameter portion 326 of the core wire 316 may be positioned proximal to at least a portion or all of the atraumatic bend 250 in the distal region of the pressure guide wire 308 to facilitate a flexible transition to the atraumatic bend 250 of the pressure guide wire 308 (shown in FIG. 2B). The core wire 316 continues to extend through at least a portion of the atraumatic bend 250. This flexible transition acts as a force absorber and ensures that no kink is formed in the proximal region of the atraumatic bend 250 of the pressure guide wire 308. A kink can complicate procedures such as advancing another catheter over the guide wire 308 or removing the guide wire 308 from the patient without trauma.

[0055] The proximal portion 328 of the core wire 316 may include an outer diameter of up to 0.03 inches, such as between 0.015 inches and 0.03 inches. The reduced-diameter portion 326 of the core wire 316 may include an outer diameter that is less than one-third or less than one-fourth of the outer diameter of the proximal portion 328 of the core wire 316. For example, the reduced-diameter portion 326 of the core wire 316 may include an outer diameter of less than 0.01 inches or less than 0.0075 inches.

[0056] The core wire 316 may include a conductive material such as stainless steel to provide a conductive path for the current applied to the guide wire 308 in connection with high-frequency pacing techniques, as described previously. The proximal end of the core wire 316 may be exposed from the proximal end of the outer tube 310 for connection to the monitor display device 204 and / or for connection to a current generator. Less than 10 percent or less than 5 percent of the length of the core wire 316 may be exposed from the proximal end of the outer tube 310 for connection to a current source for high-frequency pacing.

[0057] The pressure sensor assembly 318 may include a pressure sensor 322 and one or more pressure wire leads 320 extending from the pressure sensor 322. The pressure wire leads 320 may extend along the core wire 316. For example, the pressure sensor 322 may be an optical sensor, an electrical sensor, a membrane-based sensor, a MEMS sensor, or other device capable of generating a signal in response to a pressure level or pressure variation. The one or more pressure wire leads 320 may be optical fibers or electrical wires. As shown in FIG. 3, the pressure sensor assembly 318 may also include a sensor housing 324 disposed across the pressure sensor 322 and positioned between the outer tube 310 and the core wire 316. The sensor housing 324 may include an annular or short tubular member or cylinder on which the membrane is supported. The sensor housing 324 can improve handling during assembly in the coil portion 312.

[0058] The pressure sensor assembly 318 may be disposed between the core wire 316 and the outer tube 310 in a radial direction with the pressure sensor 322 between the reduced diameter portion 326 of the core wire 316 and the coiled portion 312 of the outer tube 310 in the radial direction. At least a portion of the pressure sensor assembly 318 may be non-coaxial with the longitudinal axis L of the pressure guide wire 308. In some configurations, the entire pressure sensor assembly 318 may be non-coaxial with the longitudinal axis of the pressure guide wire 308.

[0059] The pressure sensor 322 can be exposed to blood or other fluids through the space or gap 314 in the coil portion 312. In other variations, the outer tube 310 may include a sensor housing area with one or more openings to expose the pressure sensor 322 to blood or other fluids. The sensor housing area may be more rigid than the remaining portion of the coil portion 312. For example, the sensor housing area can be a metal tube that divides the coil portion 312 into two areas. The sensor housing area can be mounted to the distal portion of the first coil area of the coil portion 312 and the proximal portion of the second coil area of the coil portion 312. As another example, the coil portion 312 may include two integrally welded coils to create a stiffened area.

[0060] At least a portion of the pressure guide wire 308 can be covered by a smooth insulator such as a polymer layer, e.g., PTFE. The insulator can hold one or more wire leads 320 in place. When high-frequency pacing is induced through the core wire 316, the insulator can also electrically isolate the core wire 316 from the patient along the length of the insulator. The insulator can replace the need for another catheter to electrically isolate the pressure guide wire 308.

[0061] Figure 4 shows another variation of the pressure guide wire 408. The pressure guide wire 408 may include any of the features described with respect to the pressure guide wire 308. In this variation, the distal portion of the outer tube 410 may be formed by the coil portion 412. For example, the coil portion 412 may be a flat ribbon coil or a round coil. The proximal portion of the outer tube 410 may be formed by the connector tube 430. The connector tube 430 may include a conductive material to facilitate high-frequency pacing. For example, the connector tube 430 may be formed of a metal structure such as a stainless steel tube. The connector tube 430 is not covered with a coating or other insulator to enable high-frequency pacing. In some configurations, current may flow additionally or alternatively through one or more pressure wire leads 420. The connector tube 430 may be directly or indirectly connected to the coil portion 412 and / or the distal tip 432. For example, the coil portion 412 may be indirectly connected to the connector tube 430 by an insulated portion. The insulated portion can provide a length that is insulated from the patient and can thus be the insulation portion 434 in some embodiments. The insulation portion 434 can insulate the patient from the core wire 416. In some configurations, the insulation portion 434 may comprise a polymer layer such as PTFE.

[0062] At least the non-reduced diameter portion of the core wire 416 can be concentric with the outer tube 410. The core wire 416 can extend through at least the coil portion 412, but may also extend through the insulation portion 434 of the outer tube 410 and / or at least a portion of the connector tube 430. For example, the proximal end of the core wire 416 may be sealed to the distal end of the connector tube 430 using, for example, an adhesive 436 and may extend distally from the distal end of the connector tube 430.

[0063] The core wire 416 may include any of the features of the core wire 316. For example, the distal portion of the core wire 416 may include a reduced-diameter portion 426. The proximal end of the coil portion 412 may be distal to the transition between the non-reduced-diameter portion 428 and the reduced-diameter portion 426 of the core wire 416.

[0064] The pressure sensor assembly 418 may be disposed between the core wire 416 and the outer tube 410 in the radial direction with the pressure sensor 422 positioned radially between the reduced-diameter portion 426 of the core wire 416 and the coil portion 412. At least a portion of the pressure sensor assembly 418 may be non-coaxial with the longitudinal axis L of the pressure guide wire 408. For example, a first region 438a of at least one pressure wire lead 420 may be concentric with the outer tube 410, and a second region 438b of the pressure wire lead 420 may be non-coaxial with the longitudinal axis of the outer tube 410. The outer tube 410 may include an opening 440 so as to transition the pressure wire lead 420 from a first region 438a that is concentric with the outer tube 410 to a second region 438b that is non-coaxial with the longitudinal axis of the outer tube 410. The opening 440 may be a cut-away partial thickness or may extend through the entire thickness of the outer tube 410. When the opening 440 extends through the entire thickness of the outer tube 410, the opening 440 may be sealed, for example, with an adhesive 436 to prevent blood or other fluid from flowing through the opening 440 to the pressure guide wire. As shown in FIG. 4, the opening 440 is disposed in the connector tube 430. However, in other configurations, the opening 440 may be disposed in the insulating portion 434.

[0065] Instead of the opening 440, the core wire 416 can shift the pressure wire lead 420 from a first region 438a that is concentric with the outer tube 410 to a second region 438b that is non - coaxial with the longitudinal axis of the outer tube 410. The core wire 416 may be sized or shifted relative to the longitudinal axis of the pressure guide wire 408 such that the lead can transition from the first region 438a to the second region 438b. The core wire 416 may have a groove on one side configured to receive the spread of the pressure wire lead 420 such that the lead can transition from the first region 438a to the second region 438b.

[0066] The pressure guide wire 408 may comprise a distal tip 432 that is rounded to form a non - traumatic tip. For example, the distal tip 432 may have a hemispherical shape. The tip 432 may be tapered or flattened to prevent the entry of unwanted foreign objects through the distal end of the pressure guide wire 408.

[0067] In some configurations, the distal tip 432 is another component attached, welded, and / or otherwise coupled to the coil portion 412 and / or the core wire 416. The distal tip can be coupled to the inner surface of the coil portion 412 and / or the most distal edge of the coil portion 412. The core wire 416 may be bent up to 180 degrees within the outer tube 410 to strengthen the adhesive bond to the distal tip 432. In other configurations, the distal tip 432 can be the enlarged distal end of the core wire 416 that is distal to a reduced - diameter portion 426. The distal end of the core wire 416 can be attached, welded, and / or otherwise coupled to the inner surface and / or the most distal edge of the coil portion 412. In one method, the distal tip 432 is formed by deforming an enlarged section of the core wire 416 into a hemispherical member. The enlarged section may be melted to form the hemispherical member. The hemispherical member can be coupled to the distal portion of the coil portion 412. In any of these configurations, the non - traumatic portion of the distal tip 432 may be formed from the core wire 416, adhesive, and / or weld.

[0068] b. Tube - based pressure guide wire Figures 5 - 10C show further variations of the pressure guide wire that can be used in any of the methods described above. The pressure guide wires described below may include any of the features of the pressure guide wires 308, 408 described above. Generally, the pressure guide wires shown in Figures 5 - 10C include an outer tube defining a lumen, a connector tube positioned radially inward of the outer tube, a pressure sensor assembly disposed within the lumen of the outer tube, and / or a distal tip. The outer diameter of the pressure guide wire can be uniform or substantially uniform along substantially the entire or the entire working length of the pressure guide wire. For example, the outer diameter of the pressure guide wire can be uniform or substantially uniform along the entire working length except at the distal tip or the worn - out curved portion. The pressure guide wire can include an outer diameter of up to 0.035 inches, such as between 0.018 inches and 0.035 inches. In some configurations, the distal portion of the pressure guide wire can be formed with a non - traumatic curved portion 250 as shown in Figure 2B. In other configurations, the distal portion of the pressure guide wire can remain straight.

[0069] The connector tube can include an inner diameter that is less than one - third or less than one - fourth of the outer diameter of the connector tube. For example, the connector tube can have an outer diameter of up to 0.035 inches, such as between 0.018 inches and 0.035 inches, and an inner diameter of less than 0.01 inches, such as less than 0.007 inches. The connector tube can have a uniform outer diameter (see Figure 5) or a non - uniform diameter (see Figure 6). In a non - uniform configuration, the reduced - diameter portion of the connector tube can have an outer diameter of about 0.027 inches or less. The connector tube can extend along most or substantially the entire working length of the pressure guide wire. For example, the connector tube can extend for at least 80 percent, or at least 90 percent, of the working length of the pressure guide wire.

[0070] The connector tube can be constructed from a conductive metal. For example, the connector tube can be a stainless steel tube. The proximal end of the connector tube can be exposed from the proximal end of the outer tube for connection to a monitor display device and / or connection to a current generator. Thus, at least the proximal end of the connector tube may not be coated.

[0071] The pressure guide wire may include a core wire distal to the connector tube. In the application of the aortic valve for venous or apical cross-section, a portion with the core wire can be disposed in the blood flow downstream of the portion with the connector tube. In the application of the mitral valve for arterial or apical cross-section, a portion with the core wire can be disposed in the blood flow upstream of the portion with the connector tube. The core wire can include an outer diameter of up to 0.03 inches, such as between 0.018 inches and 0.03 inches. The reduced diameter portion of the core wire can include an outer diameter that is less than one-third or less than one-fourth of the outer diameter of the remaining portion of the core wire. For example, the reduced diameter portion of the core wire can include an outer diameter of less than 0.01 inches or less than 0.0075 inches. The core wire can extend along only the distal portion of the pressure guide wire, for example, less than 20 percent, less than 10 percent, or less than 5 percent of the working length of the pressure guide wire.

[0072] FIG. 5 is a schematic view of another variation of the pressure sensing guidewire 508. As shown, at least the distal portion of the outer tube 510 can be coiled. For example, the coiled portion can be a flat ribbon coil or a round coil. As shown in FIG. 5, the coiled portion can include two coiled regions 512a, 512b separated from each other by the sensor housing 542. Together, the coiled portions 512a, 512b can extend along most of the working length of the pressure guidewire 508, or along substantially the entire working length of the pressure guidewire 508. For example, together, the coiled portions 512a, 512b can extend at least 80 percent, or at least 90 percent, of the working length of the pressure guidewire 508. With the substantial length of the outer tube 510 being coiled, the coiled portions 512a, 512b provide sufficient flexibility to pass through a tortuous vasculature. The distal coiled portion 512a also promotes safety in the event of a defect along the coiled portion, such as a distal tip defect. When used for high frequency pacing, the distal coiled portion 512a can also ensure electrical contact with the inner wall of the patient's heart, such as the inner wall of the left ventricle.

[0073] As shown in FIG. 5, at least the proximal portion 528 of the core wire 516 can be concentric with the outer tube 510 and can extend through at least a portion of the lumen of the outer tube 510. The diameter of the proximal portion 528 of the core wire 516 can be the same as the outermost diameter of the connector tube 530. At least a portion of the core wire 516 can include a reduced-diameter portion 526, such as a tapered portion that tapers toward the distal end of the pressure guide wire 508. The transition between the proximal portion 528 and the reduced-diameter portion 526 of the core wire 516 can be positioned proximal to the non-traumatic bend 250 in the distal region of the pressure guide wire 508 to facilitate a flexible transition to the non-traumatic bend 250 of the pressure guide wire 508. This flexible transition acts as a force absorber and ensures that no kink is formed in the proximal region of the non-traumatic bend 250 of the pressure guide wire 508. A kink can complicate the procedure, such as advancing another catheter over the guide wire 508 or removing the guide wire 508 from the patient without trauma. The core wire 516 can include a conductive material, such as stainless steel, to provide high-frequency pacing, as described previously.

[0074] The pressure sensor assembly 518 can include a pressure sensor 522 and one or more pressure wire leads 520 extending from the pressure sensor 522. For example, the pressure sensor 522 can be an optical sensor, an electrical sensor, a membrane-based sensor, or others. The pressure wire leads 520 can be optical fibers or electrical wires. The pressure wire leads 520 can extend through the lumen of the connector tube 530. The connector tube 530 positions the pressure force wire leads 520 along the central longitudinal axis L of the pressure guide wire 508. The pressure force wire leads 520 can be fixed to the connector tube 530 and, in some cases, can be sealed to the connector tube 530, for example, using an adhesive. In some cases, the adhesive provides a seal to prevent fluid from flowing proximally through the connector tube 530. The adhesive can be used at the proximal end of the connector tube 530 to concentrically fix the optical fiber 520 to the connector tube 530.

[0075] As shown in FIG. 5, the pressure sensor 522 can be disposed within the pressure sensor housing 542 of the outer tube 510. The sensor housing 542 protects the pressure sensor 522, but also provides a connection between the coil portions 512a, 512b. The pressure sensor 522 can be exposed to blood or other fluid through at least one opening 544 in the sensor housing 542. As shown, the sensor housing 542 can be a metal tube that joins the two coil portions 512a, 512b, but in other variations, the sensor housing 542 can be formed by welding several coils together to form a welded portion that joins the coil portions 512a, 512b.

[0076] The sensor housing 542 and the pressure sensor 522 can be positioned proximal to the non-invasive bend 250 shown in FIG. 2B, such as at location 206A for example. However, as previously described, the pressure sensor can be positioned at any location along the bend 250 in the distal region of the pressure guide wire 508.

[0077] At least a portion of the pressure guide wire 508 can be covered by a smooth insulator such as a polymer layer, e.g., PTFE. The insulator can electrically isolate a portion of the pressure guide wire 508 when high-frequency pacing is induced through the connector tube 530 and / or the core wire 516. The insulator can replace the requirement for another catheter body to electrically isolate the pressure guide wire 508.

[0078] Figure 6 is a cross-sectional view of another variation of the pressure sensing guidewire 608. The pressure sensing guidewire 608 is similar to the pressure sensing guidewire 508, except as described differently later. The disclosure in connection with Figure 6 may be seen as supplementing the disclosure of Figure 5. The pressure sensing guidewire 608 includes a distal tip 632. The distal tip 632 is similar to the distal tip 432, except as described differently later. The distal tip 632 provides non-invasive interaction with blood vessels, valves, and heart wall chambers. The tip 632 can also reduce or prevent the intrusion of foreign objects, such as components or fluids, through the distal end of the pressure guidewire 608. The distal tip 632 may have a hemispherical shape.

[0079] In some configurations, the distal tip 632 is another component attached, welded, and / or otherwise coupled to the coil portion 612a and / or the core wire 616. The distal tip 632 can be coupled to the inner surface of the coil portion 612a and / or the most distal edge of the coil portion 612a. The core wire 616 may be bent up to 180 degrees within the outer tube 610 to strengthen the adhesive bond to the distal tip 632. In other configurations, the distal tip 632 can be the enlarged distal end of the core wire 616 that is distal to the reduced-diameter portion 626. The distal end of the core wire 616 can be attached, welded, and / or otherwise coupled to the inner surface and / or the most distal edge of the coil portion 612a. In any of these configurations, the non-invasive portion of the distal tip 632 can be formed from the core wire 616, such as by dissolving or reforming the enlarged section of the core wire 616 to create the desired shape.

[0080] FIG. 7 is a schematic diagram of another variation of the pressure sensing guidewire 708. The pressure sensing guidewire 708 is similar to the pressure sensing guidewire 508, except that the sensor housing 742 and the pressure sensor 722 can be positioned more distally within the distal curvature 250 of the pressure guidewire 708, such as at location 206B or 206C shown in FIG. 2B for example. However, as previously discussed, it may be beneficial to reduce the diameter of the inner core wire in order to facilitate flexibility at the transition to the distal curvature 250. Thus, the sensor housing 742 and the pressure sensor 722 can be positioned in the region where the connector tube 730 and / or the core wire 716 transition to a reduced diameter. For example, as shown in FIG. 7, the connector tube 730 may have a reduced diameter section 746 at the distal end of the connector tube 730. Optionally, the connector tube 730 may taper towards the reduced diameter section 746 at the tapered portion 754. The diameter of the proximal end of the core wire 716 can also be made smaller than the outermost diameter of the connector tube 730, for example at the distal end or distal region of the connector tube 730. In this configuration, the outer diameter of the sensor housing 742 can also be reduced compared to the sensor housing 542. The outer diameter of the proximal portion of the connector tube 730 can be less than or equal to the inner diameter of the coil portion 712b and / or greater than the inner diameter of the sensor housing 742. As shown, the proximal portion of the connector tube 730 can be positioned within the coil portion 712b, but the reduced diameter section 746 can be positioned within the sensor housing 742. In this configuration, the inner diameter of the coil portion 712a and / or the coil portion 712b can be different from the inner diameter of the sensor housing 742, such as larger than the inner diameter of the sensor housing 742 for example. The outer diameters of the coil portions 712a, 712b may be approximately the same as the outer diameter of the sensor housing 742. In other configurations, the inner diameter of the coil portion 712a and / or the coil portion 712b can be the same as the inner diameter of the sensor housing 742 (similar to the guidewire 608).

[0081] FIG. 8 is a schematic diagram of another variation of the pressure sensing guidewire 808. The pressure sensing guidewire 808 is similar to the pressure sensing guidewire 708, except that the sensor housing 842 and the pressure sensor 822 can be positioned more distally into the distal curvature 250 of the pressure guidewire 808, such as at location 206D shown in FIG. 2B, for example. However, as previously discussed, it may be beneficial to reduce the diameter of the inner core wire to facilitate flexibility at the transition to the distal curvature 250. Thus, in the region of sign 206D at the distal curvature 250, the reduced diameter portion 826 of the core wire 816 can have a diameter reduced sufficiently to allow positioning of the sensor 822 between the distal coil portion 812a in the radial direction and the reduced diameter portion 826 of the core wire 816. As shown in FIG. 8, the sensor 822 can have another sensor housing 842 positioned around the sensor 822.

[0082] Instead of a sensor housing along the outer tube 810, the pressure guidewire 808 includes a connector 848 that extends between coil portions 812a, 812b. The connector 848 can include an opening 852 so that at least one pressure wire lead 820 can be transitioned from a first region 838a that is concentric with the outer tube 810 and within the connector tube 830 to a second region 838b that is non - coaxial with the longitudinal axis L of the outer tube 810. The opening 852 can be a cut - out partial thickness or can extend through the entire thickness of the outer tube 810. If the opening 852 extends through the entire thickness of the outer tube 810, the opening 852 may be sealed, for example with an adhesive, to prevent fluid from flowing through the opening 852 into the pressure guidewire.

[0083] FIG. 9 is a cross - sectional view of another variation of the pressure sensing guidewire 908. The pressure sensing guidewire 908 is similar to the pressure sensing guidewire 808, except that FIG. 9 includes a distal tip 932. The distal tip 932 can include any of the features of the distal tip 632 shown in FIG. 6.

[0084] The outer tube 910 comprises an insulating portion 934 and a coil portion 912 coupled by a connector 948. The coil portion 912 can be a flat ribbon-shaped coil or a round coil. The insulating portion 934 surrounds at least a portion of the connector tube 930. The insulating portion 934 can comprise a polymer layer such as PTFE to electrically isolate the connector tube 930 from the patient during high-frequency pacing. The proximal end 956 of the connector tube 930 can be exposed from the proximal end of the insulating portion 934 for connection to a monitor and / or a current generator. Thus, at least the proximal end of the connector tube 930 may not be coated.

[0085] As shown, the connector 948 can be a metal tube that connects the insulating portion 934 and the coil portion 912, but in other variations, the connector 948 can be a welded portion that joins the insulating portion 934 and the coil portion 912.

[0086] One or more pressure wire leads 920 can be sealed within the inner lumen of the connector tube 930, for example using an adhesive, to prevent fluid from flowing proximally and to ensure the concentricity of the optical fiber for signal transmission.

[0087] The pressure sensor 922 can be exposed to blood or other fluid through an interval or gap in the coil portion 912. The outer tube 910 can also comprise a sensor housing region 924. The sensor housing region may be more rigid than the remainder of the coil portion 912. For example, the sensor housing region 924 can be a metal tube that divides the coil portion 912 into two regions. The sensor housing region 924 can be mounted to the distal portion of the first coil region of the coil portion 912 and the proximal portion of the second coil region of the coil portion 912. The sensor housing region 924 can comprise one or more openings to expose the pressure sensor 922 to blood or other fluid. As another example, the coil portion 912 can comprise two integrally welded coils that create a stiffened region that acts as the sensor housing region 924.

[0088] Figures 10A - 10C show cross - sectional views of the deformation of the pressure - sensing guidewire 1008. The pressure - sensing guidewire 1008 is similar to the pressure - sensing guidewire 608 or 708, except that the insulating portion 1034 may surround at least a portion of the conductive connector tube 1030 and / or the pressure wire lead 1020. As shown in FIGS. 10A and 10B, the connector tube 1030 may have a uniform diameter. However, in other configurations (see FIG. 10C), the distal portion of the connector tube 1030 may have a reduced diameter. Optionally, the connector tube 1030 may be tapered towards the distal portion of the connector tube 1030. The insulating portion 1034 may form at least a portion of the outer tube 1010. For example, as shown in FIG. 10A, the insulating portion 1034 may extend proximally from the sensor housing 1042 towards the proximal end 1056 of the pressure guidewire 1008. The proximal end 1056 of the connector tube 1030 may be exposed from the insulating portion 1034 for connection to a monitor and / or connection to a current generator for high - frequency pacing. The insulating portion 1034 electrically insulates the portion of the pressure guidewire 1008 to enable high - frequency pacing as described above. The insulating portion 1034 also provides lubricity so that the delivery system can be provided over the pressure guidewire 1008. The insulating portion 1034 may comprise a polymer layer such as PTFE. As shown in FIGS. 10A and 10B, the inner diameter of the insulating portion 1034 may be approximately the same as the inner diameter of the sensor housing 1042, and / or the outer diameter of the connector tube 1030 may be less than or equal to the inner diameter of the sensor housing 1042. However, in other configurations (see FIG. 10C), the inner diameter of the insulating portion 1034 may be different from the inner diameter of the sensor housing 1042, for example, larger than the inner diameter of the sensor housing 1042. The outer diameter of the insulating portion 1034 may be approximately the same as the outer diameter of the sensor housing 1042. The outer diameter of the proximal portion of the connector tube 1030 may be less than or equal to the inner diameter of the insulating portion 1034 and / or larger than the inner diameter of the sensor housing 1042. The outer diameter of the distal portion of the connector tube 1030 may be less than or equal to the inner diameter of the sensor housing 1042. Optionally, the connector tube 1030 may comprise a tapered portion between the proximal and distal portions of the connector tube 1030.The proximal portion of the connector tube 1030 can be positioned within the insulating portion 1034, while the distal portion of the connector tube 1030 can be positioned within the sensor housing 1042. The coil portion may surround the core wire 1016. The inner diameter of the coil portion may be the same as or different from the inner diameter of the sensor housing 1042, for example, larger than the inner diameter of the sensor housing 1042. The outer diameter of the coil portion may be approximately the same as the sensor housing 1042.

[0089] As shown in FIG. 10A, the insulating portion 1034 may extend continuously from the sensor housing 1042 to the exposed proximal end 1056 of the pressure guide wire 1008. However, as shown in FIG. 10B, the electrically conductive portion 1017 of the pressure guide wire 1008 may be exposed from the insulating portion 1034 to allow for different connection positions for the current generator, as previously described in connection with FIGS. 2E - 2F. The electrically conductive portion 1017 may be, for example, proximal to the sensor housing 1042 and / or distal to the exposed proximal end 1056, which may be spaced apart from the sensor housing 1042. For example, the electrically conductive portion 1017 may be positioned between the proximal and distal ends of the insulating portion 1034. As shown, the electrically conductive portion 1017 is part of the connector tube 1030, but the electrically conductive portion 1017 may expose a portion of the core wire 1026 or any other conductive component of the pressure guide wire 1008. The electrically conductive portion 1017 may be additional or alternative to the exposed proximal end 1056. Additional electrically conductive portions 1017 may be exposed along the length of the pressure guide wire 1008. Term

[0090] Term As used herein, relative terms such as "proximal" and "distal" are to be determined from the perspective of the user of the system. Thus, proximal refers to the direction towards the user of the system, and distal refers to the direction away from the user of the system.

[0091] As used herein, relative terms such as "upstream" and "downstream" are to be defined from the perspective of blood flow. Thus, downstream refers to the direction from the left ventricle towards the aorta.

[0092] Conditional words such as "can", "may", "is possible", or "may be" are generally intended, when not otherwise explicitly stated or otherwise understood in the context in which they are used, to convey that a particular feature, element, and / or step is included in a particular embodiment but not in other embodiments. Thus, such conditional words are generally not intended to mean that a feature, element, and / or step is required in any way for one or more embodiments.

[0093] Terms such as "comprising", "including", "having", etc. are synonyms and are used inclusively in an open-ended form and do not exclude additional elements, features, acts, operations, etc. Also, the term "or", when used, for example, to connect a listing of elements, is used in its inclusive sense (not in its exclusive sense) to mean one, some, or all of the elements in the listing.

[0094] Terms such as "approximately", "about", "generally", and "substantially" as used herein represent an amount close to the stated amount that still performs the desired function or still achieves the desired result. For example, the terms "approximately", "about", "generally", and "substantially" can refer to an amount within less than 5% of the stated amount, as the context may indicate.

[0095] The ranges disclosed in this specification cover any and all overlaps, subranges, and combinations thereof. Words such as "up to", "at least", "greater than", "less than", "between...and..." include the recited numbers. Numbers preceded by terms such as "about" or "approximately" include the recited numbers. For example, "about 4" includes "4".

[0096] Any method disclosed in this specification need not be performed in the recited order. The methods disclosed in this specification include the specific actions taken by the implementer, but may also include, either explicitly or implicitly, any third-party instructions for those actions. For example, an action such as "move the locking element distally" includes "instruct the distal movement of the locking element".

[0097] Although specific embodiments and examples are described herein, it will be understood by those skilled in the art that many aspects of the humeral assembly illustrated and described in this disclosure can still be combined and / or modified differently to form further embodiments or acceptable examples. All such improvements and variations are intended to be included within the scope of this disclosure herein. A wide variety of designs and techniques are possible. None of the features, structures, or steps disclosed in this specification are essential or indispensable.

[0098] Some embodiments are described in connection with the accompanying drawings. However, it should be understood that the figures are not drawn to scale. Distances, angles, etc. are merely illustrative and do not necessarily have an exact relationship to the actual dimensions and arrangements of the devices shown. Components may be added, removed, and / or rearranged. Further, the disclosure herein of any specific features, aspects, methods, properties, characteristics, qualities, attributes, elements, etc. in connection with various embodiments can be used in all other embodiments described herein. Also, it is recognized that any method described herein can be implemented using any device suitable for performing the recited steps.

[0099] For purposes of the present disclosure, certain aspects, advantages, and novel features are described herein. It is understood that not necessarily all such advantages can be achieved in accordance with any particular embodiment. Thus, for example, one of ordinary skill in the art will recognize that the present disclosure can be embodied or carried out in a manner that achieves one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.

[0100] Furthermore, although exemplary embodiments are described herein, the scope of any and all embodiments having equivalent elements, variations, omissions, combinations (e.g., combinations of aspects across various embodiments), adaptations, and / or modifications will be understood by those skilled in the art in the technology based on this disclosure. The limitations in the claims are to be broadly construed based on the language used in the claims and are not limited to the examples described herein or the examples described during the examination of this application, and those examples are to be construed as non-exclusive. Further, the acts of the disclosed processes and methods may be varied in any manner, including reordering the acts, and / or inserting additional acts, and / or deleting acts. Accordingly, this specification and the examples are to be considered as illustrative only, and it is intended that the true scope and spirit be indicated by the claims and the full scope of their equivalents.

Description of Reference Numerals

[0101] 10 Pigtail catheter 20 Access catheter 30 Pressure guide wire 40 Pressure sensor 200 Diagnostic system 202 Fiber optic interface cable 204 Monitor assembly, monitor display device 206A, 206B, 206C, 206D Locations 207 Handle 208 Pressure guide wire 210 Access catheter 211 Access catheter 212 Delivery system 213 Delivery system 214 Aortic pigtail catheter 217a First conductive region 217b Second conductive region 234a First insulator region 234b Second insulator region 250 Non-traumatic bend 308 Pressure guide wire 310 Outer tube 312 Coil portion 314 Spacing, gap 316 Core wire 318 Pressure sensor assembly 320 Pressure wire lead 322 Pressure sensor 324 Sensor housing 326 Reduced diameter portion 328 Proximal portion 408 Pressure guide wire 410 Outer tube 412 Coil portion 416 Core wire 418 Pressure sensor assembly 420 Pressure wire lead 422 Pressure sensor 426 Reduced diameter portion 428 Non-reduced diameter portion 430 Connector tube 432 Distal tip 434 Insulating portion 436 Adhesive 438a First region 438b Second region 440 Opening 508 Pressure sensing guide wire 510 Outer tube 512a, 512b Coiled region, coil portion, coiled portion 516 Core wire 518 Pressure sensor assembly 520 Pressure wire lead, optical fiber 522 Pressure sensor 526 Reduced diameter portion 528 Proximal portion 530 Connector tube 542 Pressure sensor housing 544 Opening 608 Pressure sensing guide wire 612a Coil portion 616 Core wire 626 Reduced-diameter portion 632 Distal tip 708 Pressure-sensing guide wire 712a, 712b Coil portions 716 Core wire 722 Pressure sensor 730 Connector tube 742 Sensor housing 746 Reduced-diameter region 754 Tapered portion 808 Pressure-sensing guide wire, pressure guide wire 810 Outer tube 812a, 812b Coil portions 816 Core wire 820 Pressure wire lead 822 Pressure sensor 826 Reduced-diameter portion 830 Connector tube 838a First region 838b Second region 842 Sensor housing 848 Connector 852 Opening 908 Pressure-sensing guide wire, pressure guide wire 910 Outer tube 912 Coil portion 922 Pressure sensor 924 Sensor housing region 930 Connector tube 932 Distal tip 934 Insulating portion 948 Connector 956 Proximal end 1008 Pressure-sensing guide wire, pressure guide wire 1010 Outer tube 1016 Core wire 1017 Electrically conductive portion 1020 Pressure wire lead 1026 Core wire 1030 Conductive connector tube 1034 Insulating portion 1042 Sensor housing 1056 Proximal end A Aorta L Longitudinal axis LA Left atrium LV Left ventricle M Mitral valve P Apex RA Right atrium

Claims

1. A guidewire comprising: a connector tube extending from a proximal end of the guidewire, the connector tube having a tube wall and a lumen extending therethrough; a core wire extending distally of the distal end of the connector tube; Sensors, and a sensor housing positioned over the sensor; a sensor assembly comprising: an insulating portion surrounding at least a portion of the connector tube, extending proximally of the sensor housing, and having a proximal end and a distal end; A guidewire comprising:

2. The guidewire of claim 1 , wherein the connector tube comprises a conductive material.

3. The guidewire of claim 1 , wherein at least one conductive section of the connector tube is exposed from the insulating portion, and wherein, during use, the at least one conductive section is located external to the patient.

4. The guidewire of claim 3 , wherein the at least one conductive section comprises a first conductive section and a second conductive section, the second conductive section being spaced from the first conductive section.

5. The guidewire of claim 4 , wherein the first conductive section is located at a proximal end of the guidewire and the second conductive section is located distal to the first conductive section.

6. The guidewire of claim 5 , wherein the second conductive section is positioned between the proximal end of the insulating portion and the distal end of the insulating portion.

7. The guidewire of claim 1 , wherein the sensor is a pressure sensor.

8. The guidewire of claim 1 further comprising a coil portion at least partially surrounding the core wire.

9. The guidewire of claim 8 , wherein the insulated portion and the coil portion have the same outer diameter.

10. The guidewire of claim 1 , wherein a distal portion of the connector tube is tapered.

11. The guidewire of claim 1 , wherein the core wire comprises a reduced diameter portion.

12. The guidewire of claim 1 , wherein the sensor is coaxial with the core wire.

13. The guidewire of claim 1 , further comprising a distal tip at a distal end of the guidewire.

14. The guidewire of claim 1 , further comprising a wire lead extending from the sensor toward a proximal end of the guidewire, the wire lead extending at least partially through the lumen of the connector tube.

15. The guidewire of claim 14 , wherein the wire lead is sealed to the connector tube to prevent fluid from flowing proximally to the proximal end of the guidewire.

16. 1. A pressure guidewire, comprising: an outer tube comprising a sensor housing and a coil portion; a connector tube positioned radially inward of the outer tube, the connector tube comprising a tube wall and a lumen extending therethrough; and a core wire positioned radially inward of the outer tube and spaced longitudinally from a distal end of the connector tube, the core wire including a reduced diameter portion; a pressure sensor assembly including a pressure sensor and a pressure wire lead extending from the pressure sensor toward a proximal end of the pressure guidewire, the pressure sensor being distal to the distal end of the connector tube and the pressure wire lead extending at least partially through the lumen of the connector tube; a distal tip at a distal end of the outer tube; A pressure guidewire comprising:

17. The pressure guidewire of claim 16 , wherein the outer tube comprises a uniform diameter.

18. The pressure guidewire of claim 16 , wherein the pressure wire lead is sealed to the connector tube to prevent fluid from flowing proximally to the proximal end of the pressure guidewire.

19. The pressure guidewire of claim 16 , wherein the pressure sensor is positioned radially between the outer tube and the core wire.

20. The pressure guidewire of claim 16 , wherein the connector tube comprises a conductive material.

21. The pressure guidewire of claim 16 , wherein at least a portion of the pressure wire lead is offset from the longitudinal axis of the connector tube.

22. 22. The pressure guidewire of claim 21, wherein the pressure wire lead is configured to transition from a first section that is concentric with the connector tube to a second section that includes the portion of the pressure wire lead that is offset from the longitudinal axis of the connector tube.

23. The pressure guidewire of claim 16 , wherein the pressure sensor is positioned within the coil portion.

24. The pressure guidewire of claim 16 , wherein the outer tube further comprises a sensor housing having at least one opening.

25. 25. The pressure guidewire of claim 24, wherein the at least one opening allows fluid to flow in a space between the connector tube and the core wire.

26. The pressure guidewire of claim 24 , wherein the pressure sensor is positioned within the sensor housing.

27. The pressure guidewire of claim 24 , wherein the pressure guidewire comprises a second coil portion extending proximally from the sensor housing.

28. 28. The pressure guidewire of claim 27, wherein the second coil portion extends from the sensor housing toward a proximal end of the pressure guidewire.

29. The pressure guidewire of claim 16 , wherein the outer tube further comprises an insulating portion extending proximally of the coil portion.

30. The pressure guidewire of claim 16 , wherein the distal tip is attached to a distal section of the core wire.

31. The pressure guidewire of claim 16 , wherein the distal tip is welded to the coil portion.

32. The pressure guidewire of claim 16 , wherein the distal tip is an enlarged distal end of the core wire.

33. The pressure guidewire of claim 16 , wherein the pressure wire lead is optical fiber.

34. The pressure guidewire of claim 16 , wherein the pressure wire lead is an electrical wire.

35. The pressure guidewire of claim 16, wherein at least a first conductive section of the connector tube and a second conductive section of the connector tube are exposed from the outer tube, and the second conductive section is spaced from the first conductive section.

36. 1. A pressure guidewire, comprising: a connector tube extending from a proximal end of the pressure guidewire, the connector tube having a tube wall and a lumen extending therethrough; a core wire extending distally of the distal end of the connector tube; Pressure sensors, a pressure wire lead extending from the pressure sensor toward the proximal end of the pressure guidewire; and a sensor housing positioned over the pressure sensor; a pressure sensor assembly comprising: an insulating portion surrounding at least a portion of the connector tube, extending proximally of the sensor housing, and having a proximal end and a distal end; Equipped with A pressure guidewire, wherein at least a first conductive section of the connector tube and a second conductive section of the connector tube are exposed from the insulating portion, and the second conductive section is spaced from the first conductive section.

37. 37. The pressure guidewire of claim 36, wherein the pressure sensor is coaxial with the core wire.

38. 37. The pressure guidewire of claim 36, wherein the first conductive section is located at a proximal end of the pressure guidewire and the second conductive section is located distal to the first conductive section.

39. 39. The pressure guidewire of claim 38, wherein the second conductive section is positioned between the proximal end of the insulating portion and the distal end of the insulating portion.

40. 1. A pressure guidewire, comprising: an insulated outer tube having a lumen extending therethrough; a pressure sensor assembly including a pressure sensor and a pressure wire lead extending from the pressure sensor toward a proximal end of the pressure guidewire; a first electrically conductive portion within the lumen and exposed from the insulated outer tube; a second electrically conductive portion within the lumen and exposed from the insulated outer tube, the second electrically conductive portion spaced apart from the first electrically conductive portion; A pressure guidewire comprising:

41. The pressure guidewire of claim 40, wherein the first conductive section is located at a proximal end of the pressure guidewire and the second conductive section is located distal to the first conductive section.

42. 1. A pressure guidewire, comprising: a connector tube extending from a proximal end of the pressure guidewire, the connector tube having a tube wall and a lumen extending therethrough; a core wire extending distally of the distal end of the connector tube and including a reduced diameter section; a coil portion positioned distal to the distal end of the connector tube and surrounding at least a portion of the core wire; a pressure sensor assembly including a pressure sensor and a pressure wire lead extending from the pressure sensor toward a proximal end of the pressure guidewire, the pressure sensor being positioned radially between the reduced diameter portion of the core wire and the coil portion such that fluid can flow through a space in the coil portion to the pressure sensor; Equipped with A pressure guidewire, wherein a first section of the pressure wire lead is concentric with the connector tube, a second section of the pressure wire lead is non-coaxial with respect to a longitudinal axis of the connector tube, and the second section of the pressure wire lead is positioned radially outward of the core wire.

43. The pressure guidewire of claim 42, wherein a proximal end of the coil portion is positioned radially outside of the reduced diameter section of the core wire.

44. 43. The pressure guidewire of claim 42, wherein the core wire is concentric with the connector tube.

45. The pressure guidewire of claim 42 , wherein the coil portion is longitudinally displaced from the distal end of the connector tube.

46. 43. The pressure guidewire of claim 42, wherein the pressure wire lead is sealed to the connector tube to prevent fluid from flowing proximally to the proximal end of the pressure guidewire.

47. The pressure guidewire of claim 42 , wherein the connector tube comprises a conductive material.

48. 43. The pressure guidewire of claim 42, further comprising an insulating portion forming an outer surface of at least a portion of the pressure guidewire.

49. 43. The pressure guidewire of claim 42, further comprising an insulating portion extending longitudinally between the distal end of the connector tube and the coil portion.

50. 43. The pressure guidewire of claim 42, wherein the tube wall of the connector tube includes an opening configured to allow the pressure wire lead to transition from the first section that is concentric with the connector tube to the second section that is non-coaxial with respect to the longitudinal axis of the connector tube.

51. 51. The pressure guidewire of claim 50, wherein the opening is sealed to prevent fluid from passing through the opening to the pressure guidewire.

52. The pressure guidewire of claim 42 , wherein at least a portion of the core wire is disposed in the lumen of the connector tube.

53. 43. The pressure guidewire of claim 42, further comprising a connector extending between the connector tube and the coil portion, the connector having an opening configured to allow the pressure wire lead to transition from the first section, which is concentric with the connector tube, to the second section, which is non-coaxial with respect to the longitudinal axis of the connector tube.

54. 54. The pressure guidewire of claim 53, wherein the pressure guidewire comprises a second coil portion extending proximally from the connector.

55. 55. The pressure guidewire of claim 54, wherein the second coil portion extends along a majority of the working length of the pressure guidewire.

56. The pressure guidewire of claim 42, wherein the pressure guidewire comprises a substantially uniform outer diameter.

57. 43. The pressure guidewire of claim 42, wherein the pressure wire lead is optical fiber.

58. 43. The pressure guidewire of claim 42, wherein the pressure wire lead is an electrical wire.

59. 43. The pressure guidewire of claim 42, further comprising a sensor housing positioned over the pressure sensor and positioned radially between the core wire and the coil portion.

60. 60. The pressure guidewire of claim 59, wherein the sensor housing is glued or welded to the core wire.

61. 43. The pressure guidewire of claim 42, wherein the coil portion includes a sensor housing section that is stiffer than other sections of the coil portion, and the pressure sensor is disposed within the sensor housing section of the coil portion.

62. 62. The pressure guidewire of claim 61, wherein the sensor housing section of the coil portion includes one or more openings for allowing fluid to reach the pressure sensor.

63. The pressure guidewire of claim 42, further comprising a distal tip positioned at a distal end of the pressure guidewire.

64. 64. The pressure guidewire of claim 63, wherein the distal tip is attached to a distal section of the core wire.

65. 64. The pressure guidewire of claim 63, wherein the distal tip is welded to the coil portion.

66. 64. The pressure guidewire of claim 63, wherein the distal tip is an enlarged distal end of the core wire.

67. an outer tube having a lumen extending therethrough and including a coil portion; a core wire positioned in the lumen of the outer tube and including a reduced diameter portion; a pressure sensor assembly including a pressure sensor and a pressure wire lead extending from the pressure sensor toward a proximal end of the pressure guidewire, the pressure sensor being positioned radially between the reduced diameter portion of the core wire and the coil portion; Equipped with A pressure guidewire, wherein at least a portion of said pressure wire lead is not concentric with said outer tube.

68. 68. The pressure guidewire of claim 67, wherein the outer tube includes an opening configured to allow the pressure wire lead to transition from a first section that is concentric with the outer tube to a second section that includes the portion of the pressure wire lead that is not concentric with the outer tube.

69. 69. The pressure guidewire of claim 68, wherein the opening is sealed to prevent fluid from passing through the opening to the pressure guidewire.

70. 68. The pressure guidewire of claim 67, wherein the pressure guidewire is configured to induce high frequency pacing.

71. 68. The pressure guidewire of claim 67, wherein a proximal end of the coil portion is positioned radially outside of the reduced diameter section of the core wire.

72. 68. The pressure guidewire of claim 67, wherein the outer tube comprises an insulating portion proximal to the coil portion.

73. 68. The pressure guidewire of claim 67, wherein the outer tube comprises a connector tube comprising a conductive material.

74. 68. The pressure guidewire of claim 67, wherein the pressure wire lead is sealed to another tube to prevent fluid from flowing proximally to the proximal end of the pressure guidewire.

75. 68. The pressure guidewire of claim 67, wherein the outer tube comprises a proximal portion comprising a conductive tube, an intermediate portion comprising an insulating portion, and a distal portion comprising the coil portion.

76. 68. The pressure guidewire of claim 67, wherein the outer tube comprises a substantially uniform diameter.

77. 68. The pressure guidewire of claim 67, wherein the core wire extends throughout the lumen of the outer tube.

78. 68. The pressure guidewire of claim 67, wherein the pressure sensor assembly further comprises a sensor housing positioned over the pressure sensor.

79. 68. The pressure guidewire of claim 67, wherein the entire outer tube is the coil portion.

80. 68. The pressure guidewire of claim 67, wherein the coil portion extends along a majority of the working length of the pressure guidewire.

81. 68. The pressure guidewire of claim 67, wherein the coil portion extends along substantially the entire working length of the pressure guidewire.

82. 68. The pressure guidewire of claim 67, wherein the coil portion is a flat ribbon coil.

83. 68. The pressure guidewire of claim 67, wherein the pressure wire lead is optical fiber.

84. 68. The pressure guidewire of claim 67, wherein the pressure wire lead is an electrical wire.

85. 68. The pressure guidewire of claim 67, further comprising a distal tip positioned at a distal end of the pressure wire.

86. 86. The pressure guidewire of claim 85, wherein the distal tip is attached to a distal section of the core wire.

87. The pressure guidewire of claim 85, wherein the distal tip is welded to the coil portion.

88. 86. The pressure guidewire of claim 85, wherein the distal tip is an enlarged distal end of the core wire.

89. 1. A method of deploying a replacement heart valve, comprising: accessing a blood flow passageway of a patient at an access location; advancing a pressure guidewire through the access location to a location adjacent the patient's heart valve to be replaced; advancing a pressure sensing device, separate from the pressure guidewire, adjacent the heart valve of the patient; advancing a delivery device having a replacement heart valve coupled thereto over the pressure guidewire; sensing pressure with the pressure sensing device on a first side of the heart valve to be replaced; sensing pressure with the pressure guidewire on a second side of the heart valve to be replaced; deploying the replacement heart valve over the heart valve to be replaced; The method includes:

90. 90. The method of claim 89, wherein the heart valve being replaced is an aortic valve.

91. 90. The method of claim 89, wherein the first side is in the aorta and the second side is in the left ventricle.

92. 90. The method of claim 89, wherein the first side is in the left ventricle and the second side is in the aorta.

93. 90. The method of claim 89, wherein the heart valve being replaced is the mitral valve.

94. 90. The method of claim 89, wherein the first side is in the left atrium and the second side is in the left ventricle.

95. 90. The method of claim 89, wherein the first side is in the left ventricle and the second side is in the left atrium.

96. 90. The method of claim 89, wherein the pressure sensing device is a pigtail catheter.

97. 90. The method of claim 89, further comprising the step of calculating a pressure gradient across the replacement heart valve.

98. 90. The method of claim 89, further comprising the step of calculating valve regurgitation of the replacement heart valve.

99. 90. The method of claim 89, further comprising the step of equalizing pressure measurements between the pressure sensing device and the pressure guidewire.

100. 100. The method of claim 99, wherein the step of equalizing pressure measurements is performed in the ventricle.

101. 100. The method of claim 99, wherein the step of equalizing pressure measurements is performed in the aorta.

102. 100. The method of claim 99, wherein the step of equalizing pressure measurements includes automatically adjusting a phase lag between a pressure curve generated from the pressure sensing device and a pressure curve generated from the pressure guidewire.

103. 100. The method of claim 99, wherein the step of equalizing pressure measurements includes the step of manually adjusting a phase lag between a pressure curve generated from the pressure sensing device and a pressure curve generated from the pressure guidewire.

104. 90. The method of claim 89, further comprising the step of directing high frequency pacing through the pressure guidewire.

105. 1. A method of assessing and / or treating a cardiac condition, comprising: advancing an access catheter through the patient's vascular system; advancing a delivery system through the access catheter and into the patient's heart; advancing a pressure sensing catheter to a first location; advancing a pressure guidewire through the access catheter to a second location different from the first location; A method comprising:

106. 106. The method of claim 105, wherein the delivery system delivers a replacement valve to the patient's heart.

107. 106. The method of claim 105, wherein the delivery system delivers an inflation balloon to the patient's heart.

108. 106. The method of claim 105, wherein the first location is in the aorta and the second location is in the left ventricle.

109. 106. The method of claim 105, wherein the first location is in the left atrium and the second location is in the left ventricle.

110. 106. The method of claim 105, wherein the pressure sensing catheter is a pigtail catheter.

111. 106. The method of claim 105, wherein the delivery system comprises a pressure sensing catheter.

112. 106. The method of claim 105, further comprising the step of guiding high frequency pacing with the pressure guidewire.

113. 106. The method of claim 105, further comprising the step of equalizing pressure measurements between the pressure sensing catheter and the pressure guidewire.

114. 114. The method of claim 113, wherein the step of equalizing pressure measurements is performed in the ventricle.

115. 114. The method of claim 113, wherein the step of equalizing pressure measurements is performed in the aorta.

116. 114. The method of claim 113, wherein the step of equalizing pressure measurements includes automatically adjusting a phase lag between a pressure curve generated from a pressure sensing device and a pressure curve generated from the pressure guidewire.

117. 114. The method of claim 113, wherein the step of equalizing pressure measurements includes manually adjusting a phase lag between a pressure curve generated from a pressure sensing device and a pressure curve generated from the pressure guidewire.

118. 1. A method of treating a structural heart condition, comprising: accessing a blood flow passageway of a patient at an access location; advancing an access catheter through the access site to a location in the heart; advancing a pressure guidewire through the access catheter; sensing pressure with said pressure guidewire; directing high frequency pacing through said pressure guidewire; A method comprising:

119. 119. The method of claim 118, further comprising the step of delivering a replacement valve through the access catheter to the heart.

120. 119. The method of claim 118, further comprising the steps of advancing a pressure sensing device and sensing pressure using the pressure sensing device.

121. 119. The method of claim 118, further comprising the step of coupling an electrical current generator to the pressure guidewire.

122. 122. The method of claim 121, wherein the step of coupling the current generator comprises the step of coupling the current generator to a proximal end of the pressure guidewire.

123. 122. The method of claim 121, wherein coupling the current generator comprises coupling the current generator to the pressure guidewire at a location spaced distally from a proximal end of the pressure guidewire.

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