Apparatus and method for measuring portal vein pressure

Abstract

A system for measuring pressure in a vein includes a needle sized and shaped to be inserted through a working channel of an endoscope. The needle extends longitudinally and includes a channel extending longitudinally therethrough. The system also includes a pressure sensing device including a longitudinally extending body sized and shaped to be slidably inserted through the channel of the needle, and a sensor mounted at a distal end of the body and connected to a proximal end of the pressure sensing device via a wired cable. The sensor provides detection information corresponding to the pressure of the blood flow passing through the vein.

Description

(Division of 201980052106.7) Priority declaration

[0001] This disclosure claims priority to U.S. Provisional Patent Application Serial No. 62 / 728,528, filed on September 7, 2018; the disclosure of which is incorporated herein by reference. Background Art

[0002] Portal pressure is used to understand and control high blood pressure, for example in patients with cirrhosis. Currently, the measurement of portal pressure is extrapolated by calculating the patient's hepatic venous pressure gradient (HVPG). Balloon catheters with sensing capabilities are used to measure the hepatic venous free pressure and the hepatic venous wedge pressure. The HVPG is calculated by taking the difference between the hepatic venous free pressure and the hepatic venous wedge pressure. However, the procedure for placing a balloon catheter is an invasive transvenous approach that only provides an approximation of portal pressure. Summary of the invention

[0003] An embodiment of the present disclosure relates to a system for measuring pressure in a vein, the system comprising a needle and a pressure sensing device; the needle is sized and shaped to be inserted through a working channel of an endoscope, and the needle extends longitudinally and includes a channel extending longitudinally therethrough, the pressure sensing device comprising a longitudinally extending body sized and shaped to be slidably inserted through the channel of the needle, and a sensor mounted at a distal end of the body and connected to a proximal end of the pressure sensing device via a wiring cable, the sensor being used to detect information corresponding to the pressure of blood flow through the vein.

[0004] In one embodiment, the pressure sensing device is longitudinally movable relative to the needle between an insertion configuration, in which the sensor is covered by a portion of the needle, and a pressure sensing configuration, in which the distal end of the body of the pressure sensing device extends distally beyond the distal end of the needle to expose the sensor to fluid flow inside the vein.

[0005] In one embodiment, the distal end of the needle may include a sharp tip for piercing the portal vein wall and the distal end of the body of the pressure sensing device may include a blunt end so that in the insertion configuration the distal end of the body is positioned relative to the sharp tip of the needle to prevent the sharp tip from damaging the working channel of the endoscope.

[0006] In one embodiment, the pressure sensing device is movable proximally relative to the needle so that the sharp tip is exposed to pierce the wall of the vein.

[0007] In one embodiment, the distal end of the body of the pressure sensing device may include a sharp tip and the distal end of the needle may be blunt, such that in the insertion configuration the sharp tip of the pressure sensing device is contained within the channel of the needle, and in the pressure sensing configuration the pressure sensing device is moved distally relative to the needle, exposing the sharp tip of the body to pierce the wall of the portal vein.

[0008] In one embodiment, in the pressure sensing configuration, the distal end of the body can be moved distally beyond the distal end of the needle by a predetermined distance. The pressure sensing device can include fins coupled to the body such that the fins are movable between a first configuration in which the fins are constrained toward an outer surface of the body in the insertion configuration and a second configuration in which the fins move radially outward in the pressure sensing configuration to engage a portion of the needle.

[0009] In one embodiment, the system may further include a stylet sized and shaped to be inserted through the passage of the needle, the stylet being longitudinally movable relative to the needle between an insertion configuration and a piercing configuration.

[0010] In one embodiment, the distal end of the stylet may include a sharp tip and the distal end of the needle may be blunt such that in the insertion configuration the sharp tip of the stylet is received within the channel of the needle and in the piercing configuration the sharp tip of the stylet is moved distally beyond the distal end of the needle.

[0011] In one embodiment, the distal end of the needle may include a sharp tip and the distal end of the stylet may be blunt, such that in the insertion configuration the distal end of the stylet is positioned relative to the distal end of the needle to prevent the sharp tip of the needle from damaging the working channel of the endoscope, and in the piercing configuration the stylet is pulled proximally relative to the needle to expose the sharp tip of the needle for piercing the portal vein wall.

[0012] In one embodiment, the sensor may be mounted in a recess that extends laterally into the body of the pressure sensing device along a distal end of the body of the pressure sensing device.

[0013] In one embodiment, the body of the pressure sensing device may include a through hole extending laterally through the distal end of the body such that the distal face of the sensor is exposed to fluid flow through the through hole.

[0014] An embodiment of the present invention also relates to a device for measuring the internal pressure of a vein; the device includes a main body extending longitudinally from the proximal end to the distal end and a sensor located at the distal end of the main body, the size and shape of the main body being designed to be inserted through a working channel of an endoscope and one of the channels of an endoscope needle, the sensor being connected to the proximal end of the device via a cable connection, and the sensor being used to detect information corresponding to the blood flow pressure passing through the vein.

[0015] In one embodiment, the device may further include a working channel extending longitudinally through the body.

[0016] In one embodiment, the sensor is movable relative to the body between a first configuration and a second configuration, wherein a portion of the sensor blocks a distal opening of a working channel extending through the body, and wherein the sensor is moved in a direction away from a central axis of the body so that a tool inserted through the working channel of the body has an unobstructed path for insertion into a vein.

[0017] In one embodiment, the device may further include a cautery needle blade slidably received within the body for forming a hole in the wall of the portal vein through which the body may be inserted to measure the pressure of the vein.

[0018] Embodiments of the present disclosure also relate to a method for measuring pressure in a vein, the method comprising inserting a needle through a working channel of an endoscope to a target area near the vein and piercing the wall of the portal vein to insert a distal end of a pressure sensing device into the vein to measure its pressure, the pressure sensing device comprising a sensor mounted at the distal end and connected to the proximal end of the device via a wiring cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of a system according to an exemplary embodiment of the present disclosure is shown;

[0020] Figure 2 Shows Figure 1 a longitudinal side view of a distal portion of a pressure sensing device of a system;

[0021] Figure 3 shows a longitudinal side view of a distal portion of a pressure sensing device according to an alternative embodiment;

[0022] Figure 4 shows a schematic diagram of a system according to another exemplary embodiment of the present disclosure;

[0023] Figure 5 A schematic diagram showing a system according to yet another exemplary embodiment of the present disclosure is shown;

[0024] Figure 6 shows a schematic diagram of a system according to another exemplary embodiment of the present disclosure;

[0025] Figure 7 A pressure sensing device according to an alternative embodiment of the present disclosure is shown. Figure 6 Schematic diagram of the system.

[0026] Figure 8 A pressure sensing device according to another alternative embodiment of the present disclosure is shown. Figure 6 Schematic diagram of the system;

[0027] Fig. 9 shows a longitudinal side view of a distal portion of a system in a first configuration according to another exemplary embodiment of the present disclosure;

[0028] Fig.10 The second configuration is shown Fig. 9 A longitudinal side view of a distal portion of the system;

[0029] Fig.11 The third configuration is shown Fig. 9 A longitudinal side view of a distal portion of the system;

[0030] Fig.12 showing a longitudinal side view of a distal portion of a system in a first configuration according to an alternative embodiment of the present disclosure;

[0031] Fig.13 The second configuration is shown Fig.12 A longitudinal side view of a distal portion of the system;

[0032] Fig.14 shows a longitudinal side view of a distal portion of a system in a first configuration according to yet another exemplary embodiment of the present disclosure;

[0033] Fig.15 The second configuration is shown Fig.14 A longitudinal side view of a distal portion of the system;

[0034] Fig.16 shows a schematic diagram of a system according to another exemplary embodiment of the present disclosure;

[0035] Fig.17 shows a longitudinal side view of a pressure sensing device according to another exemplary embodiment of the present disclosure;

[0036] Fig.18 Shows Fig.17 A cross-sectional view of a pressure sensing device;

[0037] Fig.19 shows a longitudinal side view of a pressure sensing device according to an alternative embodiment;

[0038] Fig. 20 Shows Fig.19 A cross-sectional view of a pressure sensing device;

[0039] Fig.21A schematic diagram showing a system according to yet another exemplary embodiment of the present disclosure is shown;

[0040] Fig. 22 shows a longitudinal side view of a system in a first configuration according to another exemplary embodiment of the present disclosure;

[0041] Fig.23 The second configuration is shown Fig. 22 A longitudinal side view of the system;

[0042] Fig.24 Shows Fig. 22 An enlarged side view of a sensor of the system;

[0043] Fig.25 Shows Fig.24 An enlarged end view of the sensor;

[0044] Fig.26 shows a schematic diagram of a passive sensor according to an exemplary embodiment of the present disclosure;

[0045] Fig. 27 A schematic diagram of a passive sensor according to another exemplary embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0046] The present disclosure can be further understood with reference to the following description and accompanying drawings, in which similar elements are marked with the same reference numerals. The present disclosure relates to a system and method for measuring portal vein pressure, specifically describing the insertion of a pressure sensing device into the portal vein via a needle guided to the portal vein under endoscopic ultrasound guidance. The pressure sensing device is directly inserted into the portal vein to measure the portal vein pressure. Therefore, the present disclosure provides a non-invasive system and method for providing accurate measurement of portal vein pressure. Although these exemplary embodiments specifically illustrate and describe the pressure sensing device as including a sensor for measuring the internal pressure of the portal vein, the sensor can also measure other information in addition to pressure. Therefore, it should be understood by those skilled in the art that the following systems and methods can also be used to obtain and measure information in addition to portal vein pressure. It should be noted that the terms "proximal" and "distal" as used herein are intended to refer to the direction toward (proximal direction) and away from (distal direction) the user of the device.

[0047] like Figure 1 As shown in , a system 100 for measuring pressure inside a portal vein 10 according to an exemplary embodiment of the present disclosure includes a needle 102 as well as a stylet 104 and a pressure sensing device 106 , each of which can be passed through a channel 108 of the needle 102 . Figure 1Further illustrated are steps 1-4 of obtaining access to the portal vein 10 using the system 100. Initially, the needle 102, with the stylet 104 received within the channel 108 to prevent tissue from entering the channel 108 during insertion, may be positioned proximate to the patient's portal vein 10 through the working channel of a flexible endoscope, as shown in step 1. Once the needle 102 has been placed at a desired location proximate to the vein, the stylet 104 may be removed from the needle, as shown in step 2, and the sharp distal tip 110 of the needle 102 may be advanced to pierce the wall 12 of the portal vein 10 so as to position the distal opening of the needle 102 within the vein 10, as shown in step 3. When access to the portal vein 10 is obtained, the pressure sensing device 106 is inserted into the portal vein 10 through the channel 108, as shown in step 4, such that the pressure sensor 112 at the distal end 114 of the pressure sensing device 106 is exposed to blood flow through the portal vein 10 to measure the pressure in the vein 10.

[0048] The needle 102 extends longitudinally from a proximal end (not shown) to a distal end 116 and includes a channel 108 extending therethrough. The needle 102 is preferably flexible and sized and shaped to be inserted through a working channel of a flexible endoscope, and is specifically visible under ultrasound guidance so that the needle 102 can be guided to a desired location proximate to the portal vein 10. In the present embodiment, the distal end 116 of the needle 102 includes a sharp distal tip 110 to facilitate puncture of the portal vein 10.

[0049] The stylet 104 extends longitudinally from a proximal end (not shown) to a distal end 118 and is sized and shaped to slide within the channel 108 of the needle 102. The distal end 118 is blunt so that in the inserted configuration the stylet 104 is received within the channel of the needle 102 and the blunt distal end 118 is aligned with or extends slightly distally beyond the distal end 116 of the needle 102 to minimize damage to non-target tissue when the tip 110 of the needle 102 is moved to a target site adjacent to the vein 10 (i.e., to prevent the needle 102 from inadvertently piercing or damaging tissue near the path along which the needle is inserted into the target site, and to prevent tissue from being collected within the channel 108 during the insertion of the needle 102 into the target site).

[0050] In this embodiment, the pressure sensing device 106 includes a flexible body 120 and a pressure sensor 112 positioned along its distal end 114. It will be appreciated by those skilled in the art that the body 120 is preferably flexible enough to allow the body 120 to pass through the working channel of a flexible endoscope as the endoscope traverses a tortuous path to a target site adjacent to the vein 10. The body 120 extends from a proximal end (not shown) to a distal end 122 and is sized and shaped to be slidably inserted into the channel 108 of the needle 102. The pressure sensor 112 may be connected to the proximal end of the device 106 via, for example, a wiring cable 124 or via other data transmission media extending proximally through the pressure sensor 112 and along the length of the body 120. The pressure sensor 112 may be an optical sensor or an electrical sensor. As will be appreciated by those skilled in the art, an optical sensor may require a fluid to flow through it, which may be analyzed to calculate a corresponding pressure value, while an electrical sensor may only require contact with the blood inside the vein to measure its blood pressure. However, it will be appreciated by those skilled in the art that any sensor capable of measuring the pressure within the vein 10 may be used and the sensor may transmit data to a data processing device in any known manner, including, for example, wireless, fiber optic, and wired connections. The pressure sensor 112 may be housed within the body 120 or mounted along the body 120 in any of a number of configurations, as will be appreciated by those skilled in the art.

[0051] In such Figure 2 In one embodiment shown in , the distal end 114 of the body 120 includes a groove 126 extending laterally therein, and the sensor 112 is positioned in the groove. In the case where the sensor 112 is, for example, a diaphragm-based optical sensor, the sensor 112 may include a diaphragm 113 disposed at an angle to allow sufficient flow therethrough. In the case where the sensor 112 is an electrical sensor, this configuration also allows for sufficient fluid contact. In the case of Figure 3 In another embodiment shown in , the distal end 114' of the body 120' of the pressure sensing device 106' includes a hole 126' that extends transversely therethrough so that fluid flows through the hole 126' through the distal face 113' of the sensor 112' housed within the distal end 114'. In this embodiment, the sensor 112' can be, for example, an optical sensor having a distally facing diaphragm. This embodiment can be particularly suitable for reducing / preventing the formation of air bubbles near the pressure sensor 112', which can result in inaccurate pressure readings. A positioning ring can be housed within the interior of the distal end 114' to secure the pressure sensor 112' therein so that the pressure sensor 112' does not contact any portion of the body 120', which can result in damage to the pressure sensing device 106' during insertion through the tortuous path of the patient's body.

[0052] According to one exemplary technique of using the system 100, the needle 102 with the stylet 104 received therein in an insertion configuration is inserted through the working channel of the endoscope to a target area proximate to the portal vein 10. As will be appreciated by those skilled in the art, the needle 102 may be guided to the portal vein 10 under, for example, endoscopic ultrasound (EUS) guidance through, for example, the stomach or duodenum. Once the needle 102 is in a desired location proximate to the portal vein 10, the stylet 104 may be withdrawn from the channel of the needle 102, exposing the sharp distal end of the needle 102 and the needle 102 may be moved distally to penetrate the portal vein 10. When access to the portal vein 10 is obtained through the needle 102, a pressure sensing device may then be inserted through the channel 108 of the needle 102 until the pressure sensor 112 extends distally inside the portal vein 10 beyond the distal end 116 of the needle 102. The pressure sensor 112 inside the portal vein 10 then provides its blood pressure measurement. For example, as described above, blood flow inside the portal vein 10 flows along the septum of the pressure sensor 112 or contacts the fluid, so that the pressure sensor 112 provides a reading of the pressure measurement. Once the pressure of the portal vein 10 has been obtained, the needle 102 and the pressure sensing device 106 can be removed from the patient's body. If desired, the pressure sensing device can be optionally removed from the needle 102, and the stylet 104 can be reinserted into the insertion configuration when the needle 102 is withdrawn proximally and backward into the endoscope for removal from the body.

[0053] Although the system 100 is illustrated and described as including a pressure sensing device 106 including a pressure sensor 112 along a distal end 114 of an elongated body 120 thereof so that the pressure sensing device 106 can be immediately removed from the body when a pressure measurement is obtained, according to another exemplary embodiment, the system 100 can include a pressure sensing device that is disposed within the portal vein 10 to provide periodic monitoring of portal vein pressure. Fig.26 In the present embodiment shown in , the pressure sensing device includes a pressure sensor 112 ″, which can be pushed through the needle 102 and into the portal vein 10 via, for example, a stylet 104 or any other delivery device. The pressure sensor 112 ″ can be a wireless passive sensor that includes a resonant tank circuit with a parallel inductor and capacitor. In the example Fig.26 In one embodiment shown in FIG. 1 , the passive sensor can be formed into a 1 mm x 1 mm format using micro-machined traces for two parallel inductors sandwiching an insulating substrate. These parallel inductor traces can be used to form a parallel plate capacitor for the sensor. The passive sensor can be secured inside the portal vein 10 using, for example, a nickel titanium alloy anchor cable that can function as an inductor or a portion of an inductor of a resonant tank circuit sensor. In FIG. Fig. 27In another embodiment shown in , the capacitor can be micromachined on a polymer substrate attached to a loop wire.

[0054] In one embodiment, the induction line or induction coil trace can be designed (trace engineer) to several 10 seconds of nH. In a specific example, the inductance can be 47nH. The capacitance should be as large as possible to ensure a lower resonant frequency under a given physical constraint and can have a minimum value of 1pF in an example. In one embodiment, the polymer substrate acting as an insulator can be composed of a polymer that will provide pressure below while maintaining a relative permittivity greater than 4. According to an example, the polymer substrate can have a thickness of 10um. In one embodiment, high Q (quality factor) is ideal and can be achieved by increasing the number of turns and evenly dividing the coil from the top and bottom layers to maintain the ratio of L / C at a high value. In one embodiment, the resonant frequency should be sufficiently low to allow coupling from outside the body (e.g., below 1GHz) and keep the waveform factor sufficiently small so as not to interfere with blood flow. In one embodiment, the resonant frequency can range between 800MHz and 1000MHz.

[0055] According to one example, the dielectric constant of a flexible laminate made of a polymer (e.g., 9 or 10) can allow a passive resonant circuit to have a high Q and a small size. Nitinol wire that can be used to fix the passive sensor can allow for more flexible fixation. Controlling the length of the anchor wire will allow an inductor with an inductance value in the range of 33-47nH, so that the capacitance value of the parallel plate capacitor sensor on the end is between 0.8pF and 1.2pF within the spatial constraints of a disk with a size of less than 1mm, so as to resonate in the MHz range of 800MHz to 1000.

[0056] For example, the passive sensor 112" may be read using a near field communication device which, when deployed from the subject, may be tuned to the resonant frequency of the passive circuit. The resonant frequency will shift in response to changes in pressure, and thus an extrapolation of pressure is achieved by tracking changes in pressure employed in the system relative to its neutral state prior to introduction into the system. In one embodiment, the near field communication device may be applied using a smartphone. A device comprising a deformation of a loop antenna multiplexed from transmit to receive with a voltage controlled oscillator and receiver would be attached to the smartphone and controlled by an application running on the phone. The application would detect the peak output from the passive sensor and read the frequency setting at the peak. When the passive sensor is manufactured, there will be a linear correlation with frequency and pressure. A calibration of the baseline frequency and sensitivity will be established during initial testing of the application for the smartphone. Readings may be taken from the subject by placing the smartphone near the target area until, for example, optimal signal strength is displayed on the phone. Periodic readings of the frequency may be required to monitor changes in pressure.

[0057] like Figure 4 As shown in FIG. 1 , a system 200 according to another exemplary embodiment of the present disclosure is generally similar to the system 100 described above, including a needle 202 and a pressure sensing device 206. However, the system 200 does not require a stylet to gain access to the interior of the portal vein 20, such as Figure 4 Instead, during the insertion of the needle 202 through the working channel of the endoscope to the target area near the portal vein 20, the pressure sensing device 206 including the blunt distal end 222 is received inside the channel 208 of the needle 202. Similar to the stylet 104 of the system 100, the pressure sensing device 206 of the present embodiment is positioned inside the channel 208 of the needle 202 so that the blunt distal end 222 of the pressure sensing device 206 prevents tissue from entering the channel 208 and / or prevents the sharp tip 210 of the needle 202 from damaging the working channel of the endoscope during the insertion of the needle 202 through the working channel of the endoscope and also prevents damage to non-target tissue when the needle 202 is extended distally from the endoscope.

[0058] The needle 202 and pressure sensing device 206 are generally similar to the needle 102 and pressure sensing device 106 of the system 100. As described above, the pressure sensing device 206 includes a blunt distal end 222 and prevents the sharp distal tip 210 of the needle 202 from damaging the working channel of the endoscope during insertion. Therefore, in the insertion configuration, the pressure sensing device 206 is positioned inside the needle 202 so that the blunt distal end 222 is positioned to align with or protrude slightly distally beyond the sharp distal tip 210 of the needle 202. Therefore, in this embodiment, the pressure sensor 212 must be positioned along the distal end 214 of the longitudinal body 220 of the pressure sensing device 206 so that when the pressure sensing device 206 is in the insertion configuration relative to the needle 202, the pressure sensor 212 is covered by a portion of the needle 202. In other words, where the sharp distal tip 210 of the needle 202 is formed by forming a taper at the distal end 216 of the needle 202, the pressure sensor 212 should be a sufficient distance from the distal end 222 of the body 220 so that the pressure sensor 212 is completely covered by a portion of the needle 202 regardless of the rotational orientation of the pressure sensing device 206 inside the needle 202.

[0059] System 200 may be used in a manner generally similar to system 100. However, needle 202 is inserted into a target area with pressure sensing device 206 received inside needle 202 in an inserted configuration, as shown in step 1. Once needle 202 has reached the target area, pressure sensing device 206 may be pulled proximally relative to needle 202 such that sharp distal tip 210 of needle 202 is exposed, as shown in step 2. Needle 202 is then advanced distally such that wall 22 of portal vein 20 is pierced by sharp distal tip 210 and needle 202 extends into the interior of portal vein, as shown in step 3. When access to the interior of portal vein 20 is obtained, pressure sensing device 206 is moved distally relative to needle 202 until pressure sensor 212 extends distally beyond distal end 216 of needle 202 to measure pressure inside portal vein 20, as shown in step 4.

[0060] like Figure 5 As shown in , a system 300 according to another exemplary embodiment may be substantially similar to the system 100 described above, including a needle 302 , a stylet 304 , and a pressure sensing device 306 . Figure 5 Steps 1 to 5 are shown for gaining access to portal vein 30 using system 300. Similar to system 100, in the insertion configuration, with stylet 304 received in needle 302, needle 302 can be inserted through the working channel of an endoscope to a target area proximate portal vein 30. However, in this embodiment, portal vein 30 is pierced using sharp distal tip 318 of stylet 304 rather than needle 302.

[0061] Needle 302 can be generally similar to needle 102 described above. However, distal end 316 of needle 302 need not include a sharp tip. Distal end 316 can, for example, include a distal face extending generally orthogonally to the longitudinal axis of needle 302, since needle 302 is not required to pierce portal vein 30.

[0062] In this embodiment, the stylet 304 can be substantially similar to the stylet 104 described above with respect to the system 100. However, the stylet 304 includes a sharp distal tip 318. The sharp distal tip 318 can be formed in any of a number of configurations. In one example, the sharp distal tip 318 can be formed by a tapered distally facing surface extending at a non-perpendicular angle relative to the longitudinal axis of the stylet 304.

[0063] In the insertion configuration, the stylet 304 is received within the channel 308 of the needle 302 such that the distal tip 318 is aligned with or slightly proximal to the distal end 316 of the needle 302, as shown in step 1. This prevents the sharp distal tip 318 of the stylet 304 from damaging the working channel of the endoscope while also preventing any unintentional collection of tissue within it. However, once the needle 302 and stylet 304 have reached the target area near the portal vein 30, the needle 302 is pulled proximally relative to the stylet 304 such that the sharp distal tip 318 of the stylet 304 is exposed in the puncture configuration, as shown in step 2. In the puncture configuration, the needle 302 and stylet 304 are moved distally until the sharp distal tip 318 of the stylet 302 penetrates the portal vein 30, as shown in step 3. After the stylet 304 has pierced the portal vein 30, the needle 302 is advanced distally over (down the stylet 304) to enter the portal vein 30. After the distal end 316 of the needle 302 has been positioned inside the portal vein 30 as desired, the stylet 304 can be removed, as shown in step 4, and the pressure sensing device 306 can then be inserted through the needle 302, as shown in step 5, until the pressure sensor 312 mounted and / or positioned along the body 320 of the pressure sensing device 306 is exposed to the fluid flowing through the portal vein 30 to achieve portal vein pressure measurement.

[0064] like Figure 6 As shown in , system 400 can be generally similar to systems 200, 300 described above. Similar to system 200, system 400 includes a needle 402 and a pressure sensing device 406, which can be used to access portal vein 40, such as Figure 6402 is shown in steps 1 and 2 of . Similar to system 200, when needle 402 is inserted through the working channel of the endoscope to the target area near portal vein 40 and pressure sensing device 406 is received inside needle 402 in the insertion configuration, system 400 does not require a separate stylet. However, in this embodiment, the portal vein 40 is pierced using the sharp distal tip 422 of pressure sensing device 406 rather than the distal end 416 of needle 402. Therefore, needle 402 is generally similar to needle 302 that does not include a sharp distal tip, as described above with respect to system 300.

[0065] The pressure sensing device 406 can be generally similar to the pressure sensing device 206 described above, including a longitudinally extending body 420 and a pressure sensor 412 positioned along a distal end 414 thereof. However, rather than a blunt distal end, the distal end 422 of the body 420 includes a sharp tip 428, which can be formed by a tapered distal end 422. The sharp tip 428 can have any of a number of configurations. In one example, the sharp tip 428 can be formed by a tapered distal-facing surface extending at a non-perpendicular angle relative to the longitudinal axis of the body 420. In an embodiment, the sharp tip 428 can be formed by a tapered distal-facing surface extending at a non-perpendicular angle relative to the longitudinal axis of the body 420. Figure 7 In another example shown in , the distal end 422' of the body 420' of the pressure sensing device 406' can be generally tapered to form a sharp tip 428'. Figure 8 In yet another example shown in FIG. 4 , the distal end 422″ of the body 420″ may include a blunt edge 430″ and a sharp tip 428″ extending distally therefrom. The sharp tip 428″ may be generally conical. Figure 7 and Figure 8 In the two examples shown in , the sharp tips 428', 428" are generally centered relative to the longitudinal axis of the body 420', 420", respectively. Because the sharp tips 428', 428" are centered, the possibility of the sharp tips 428', 428" damaging the working channel of the endoscope is reduced, and thus, if necessary, the force sensing device including the sharp tips 428', 428" can be inserted directly through the working channel of the endoscope without using the needle 402 to gain access to the portal vein.

[0066] like Figure 9-11As shown in , a system 500 according to another exemplary embodiment of the present disclosure may be substantially similar to the systems 200, 400 described above, including a needle 502 and a pressure sensing device 506. However, the needle 502 and the pressure sensing device 506 include additional features that allow the needle 502 and the pressure sensing device 506 to interact so that the distal end 522 of the pressure sensing device 506 moves distally beyond the distal end 516 of the needle 502 by a predetermined distance when moving from the insertion configuration to the pressure sensing configuration. It should be understood by those skilled in the art that this feature can be used to measure the pressure inside the portal vein because the portal vein is relatively small compared to other veins. Therefore, a predetermined distance between the distal end 522 of the pressure sensing device 506 and the distal end 516 of the needle 502 can be set in the pressure sensing configuration so that when the system is in the working position (i.e., in the portal vein) in the pressure sensing configuration, the distal end 522 of the pressure sensing device 506 does not contact and / or pierce the distal wall of the portal vein into which it has been inserted, thereby preventing damage to the portal vein.

[0067] Needle 502 can be generally similar to needle 202 or needle 402, including a channel 508 through which pressure sensing device 506 can be inserted. Pressure sensing device 506 can be generally similar to pressure sensing device 206 or 406, including a body 520 with a pressure sensor (not shown) positioned along its distal end. The distal end of needle 502 or body 520 can include a sharp tip for puncturing and gaining access to the portal vein. To prevent pressure sensing device 506 from moving relative to needle 502 beyond a predetermined distance, body 520 includes fins 532 that are movable between a constrained configuration, in which fins 532 move toward an outer surface 534 of body 520 of pressure sensing device 506, and an outwardly biased configuration, in which fins 532 move radially outward in a direction away from outer surface 534 of body 520. When the fins 532 are in the constrained configuration, the pressure sensing device 506 can be received within the channel 508 of the needle 502, so that the system 500 is in the insertion configuration. When the pressure sensing device 506 is moved distally relative to the needle 502 toward the pressure sensing configuration, the fins 532 return to their outwardly biased configuration to engage with a portion of the needle 502, thereby preventing the pressure sensing device 506 from further distally moving relative to the needle 502.

[0068] When in the insertion configuration, the fins 532 are constrained by the inner surface of the channel 508 of the needle 502. When the pressure sensing device 506 is moved distally relative to the needle 502, the fins 532 are released to return to their outwardly biased configuration, thereby engaging with the distal end of the needle 502 (e.g., a groove or groove along the distal end of the inner surface of the channel 508) when in the pressure sensing configuration. In this embodiment, the movement of the fins 532 can be controlled by one or more pull wires 536, so that if it is desired to pull the pressure sensing device 506 back into the needle 502 toward the insertion configuration, the pull wire 536 can be pulled proximally relative to the pressure sensing device 506, so that the fins 532 move toward the constrained configuration, and the pressure sensing device 506 can be pulled back into the channel 508.

[0069] According to Figure 12-13 In another example shown in , system 500' can be substantially similar to system 500, including needle 502' and pressure sensing device 506', with features that include features such that when in the pressure sensing configuration, the pressure sensing device interacts with these features to cause the distal end 522' of the pressure sensing device 506' to move distally beyond the distal end 516' of the needle 502' by a predetermined distance. Similar to pressure sensing device 506, body 520' of pressure sensing device 506' includes fins 532' that can move between a constrained configuration and an outwardly biased configuration, wherein the fins 532' engage corresponding portions of the needle 502' when in the pressure sensing configuration. However, in this embodiment, the fins 532' cannot be controlled by a pull wire. Rather, the fin 532' is connected to the body 520' and is configured such that, when it is desired to move the system 500' from the pressure sensing configuration to the insertion configuration, moving the pressure sensing device 506 proximally relative to the needle 502' causes the fin 532' to be constrained toward the constrained configuration so that the pressure sensing device 506' can be pulled into the channel 508' of the needle 502'.

[0070] For example, the proximal end 538' of the fin 532' can be connected to the body 520' so that the distal end 540' of the fin 532' can be moved in a direction toward and away from the inner surface 534' of the body 520' in the insertion configuration and the pressure sensing configuration, respectively. The fin 532' can be configured to engage with a groove 542' having a corresponding size and shape along the distal end of the channel 508' in the pressure sensing configuration. The groove 542' can include, for example, an inclined surface 544' that extends proximally from the groove 542', so that when the fin 532' is slid proximally against the inclined surface 544', the fin 532' is moved toward the constrained configuration, thereby pulling the pressure sensing device 506' proximally into the channel 508' of the needle 502'.

[0071] like Figure 14-15 As shown in , the system 500" can be generally similar to the systems 500, 500' described above, including a needle 502" and a pressure sensing device 506", which includes a body 520", which has a fin 532" to allow the distal end 522" of the pressure sensing device 506" to move distally beyond the distal end 516" of the needle 502" to a predetermined distance. However, in this embodiment, the fin 532" is not movable. Instead, the system 500" is configured so that the distal end 540" of the fin 532" abuts against the radially inwardly extending protrusion 542" of the channel 508" of the needle 502", thereby preventing any further distal movement of the pressure sensing device 506" relative to the needle 502". Therefore, the radially inwardly extending protrusion 542" of the needle 502" acts as a stopper, thereby preventing the fin 532" of the pressure sensing device 506" from moving distally beyond the stopper.

[0072] Although system 500 (along with systems 500' and 500") specifically illustrates and describes fins 532 for controlling the distance that the distal end 522 of the body 520 of the pressure sensing device 506 extends distally from the distal end 516 of the needle 502, it will be appreciated by those skilled in the art that the system may include any of a variety of other features for controlling the distance that the distal end 522 of the pressure sensor 506 extends beyond the distal end 516 of the needle. For example, a handle assembly of system 500 may include a feature (e.g., a spring-loaded slider, a slider with a twist lock, or a button) that causes the distal end 522 of the pressure sensing device 506 to protrude a predetermined distance from the needle 502.

[0073] like Fig.16 As shown in , a system 600 according to another exemplary embodiment includes a pressure sensing device 606 similar to the pressure sensing device described above, including a longitudinally extending body 620 with a pressure sensor 612 positioned along its distal end 614. However, the pressure sensing device 606 further includes a retractable needle knife 646 that is longitudinally movably housed within the body 620 for cutting a small hole 622 through the wall of the portal vein 60 to gain access to the portal vein. Because the pressure sensing device 606 in this embodiment includes the needle knife 646 for gaining access to the portal vein 60, a separate needle and / or stylet is not required.

[0074] The pressure sensing device 606 may include a lumen 650 extending longitudinally through the body 620, which lumen 650 may slidably receive a needle knife 646 therein. The needle knife 646 may be movable between an insertion configuration, in which a distal end 648 of the needle knife 646 does not extend distally beyond the distal end 622 of the body 620 of the pressure sensing device 606, and a cutting configuration, in which the needle knife 646 is moved distally relative to the body 620 such that the distal end 648 of the needle knife 646 extends distally beyond the distal end 622 of the body 620 to cut a small hole through the wall 62 of the portal vein 60. In one embodiment, the distal end 648 of the needle knife 646 may be sharp enough to form a small hole through the vein through which the body 620 of the pressure sensing device 606 may be inserted. In another embodiment, the needle knife 646 may utilize thermal cautery to form a small hole through the wall 62 of the portal vein 60. Needle knife 646 is capable of forming a smaller hole in the wall 62 of the portal vein than a hole formed using a conventional needle, which may be advantageous depending on the extent of disease experienced by the patient.

[0075] Fig.16 Steps 1 to 4 of gaining access to the portal vein 60 using the pressure sensing device 606 are shown. The pressure sensing device 606 can be inserted directly through the working channel of the endoscope into the target area inside the patient's body in the insertion configuration with the needle knife 646 contained inside the body 620. As shown in step 1, the distal end 622 of the body 620 of the pressure sensing device 606 is located at the target location near the wall 62 of the portal vein 60. Once the pressure sensing device 506 is at the target location, the needle knife 646 is moved from the insertion configuration to the cutting configuration, as shown in step 2. The distal end 648 of the needle knife 646 can then be used to form a small hole in the wall 62 of the portal vein 60, and the distal end 622 of the body 620 can follow through the small hole, as shown in step 3. As shown in step 4, the body 620 is inserted through the small hole until the pressure sensor 612 is exposed to blood flow passing through the portal vein 60. Once the body 620 has entered the portal vein 60, the needle knife 646 can be retracted into the body toward the insertion configuration to prevent damage to the portal vein 60 while taking pressure readings.

[0076] Although the pressure sensing device 600 is illustrated and described as being inserted through the working channel of an endoscope to gain access to the portal vein 60, it will be appreciated by those skilled in the art that the pressure sensing device 606 may also be used with a needle, generally as described above with respect to the systems 200, 400. Inserting the pressure sensing device 606 with the needle may be particularly useful in situations where access to the portal vein through the stomach or duodenum is contemplated. Once the needle is in the liver, a needle knife 646 may be used to gain access to the vein, thereby reducing potential bleeding.

[0077] like Figure 17-Figure 18As shown in , a pressure sensing device 706 according to another exemplary embodiment can be applied to any of the systems 100-500, as described above. The pressure sensing device 706 can be generally similar to the pressure sensing devices 106-506, including a longitudinally extending body 720, the body 720 including a pressure sensor 712, the pressure sensor 712 is positioned along the distal end 714 of the body 720 and connected to the proximal end of the pressure sensing device 706 via a wiring cable 724 (e.g., conductive fiber, optical fiber) extending proximally from the pressure sensor 712 along the length of the body 720. However, the pressure sensing device 706 further includes a working channel 752 extending through the body 720 so that other diagnostic tools and / or therapeutic tools can be inserted into the portal vein through the working channel 752. The working channel 752 can extend along a longitudinal center axis generally parallel to the body 720.

[0078] The pressure sensor 712 may also be offset from the longitudinal center axis of the body 720 such that the patch cable 724 extends generally parallel to the longitudinal center axis of the body 720. In one embodiment, the pressure sensor 712 may have a distally facing septum 713 and / or reading surface such that the pressure sensor is mounted inside the distal end 722 of the body 720 such that the distally facing septum is generally flush with the distal end 722. The pressure sensing device 706 may be used in generally the same manner as described above with respect to the systems 100-500 (e.g., inserted through a channel of a needle) to gain access to the portal vein and obtain pressure measurements therein.

[0079] According to Figure 19-20 In an alternative embodiment shown in , pressure sensing device 706' can be substantially similar to pressure sensing device 706, including a longitudinal body 720' including a pressure sensor 712' connected to the proximal end of device 706' via a wiring cable 724' and a working channel 752' extending longitudinally through body 720'. However, pressure sensor 712' can be mounted within a recess 726' extending laterally through distal end 714' of body 720', similar to that described with respect to Figure 2 1 and 10. In this embodiment, because the pressure sensor 712' is spaced from the distal end 722' of the body 720', the distal end 722' can be blunt (as shown) or can alternatively include a sharp tip for piercing the portal vein. Similar to the pressure sensing device 706, the pressure sensing device 706' can be used in a manner generally similar to the sensing devices 106-506, as described above with respect to the systems 100-500.

[0080] like Fig.21As shown in , system 800 can be substantially similar to the systems described above (eg, systems 200 , 400 ), including a needle 802 and a pressure sensing device 806 , which can be substantially similar to pressure sensing device 706 . Fig.21 Steps 1 and 2 are shown for measuring pressure inside the portal vein and / or providing treatment to the portal vein with a pressure sensing device 806 inserted therein. Needle 802 may be substantially similar to needles 202, 402, including a longitudinal channel 808 that may slidably receive pressure sensing device 806. Pressure sensing device 806 may be substantially similar to pressure sensing device 706, including a working channel 852 that extends through a longitudinally extending body 820 of pressure sensing device 806 for passage of another tool 860 (e.g., a diagnostic tool and / or a therapeutic tool). However, pressure sensor 812 is not fixed within or along body 820. Rather, the pressure sensor 812 is movably housed within the body 820 between a first configuration (step 1) in which the pressure sensor 812 is received within the distal end 822 of the body 820 and a second configuration (step 2) in which the pressure sensor 812 is moved distally from the distal end 822, such that the pressure sensor 812, which is connected to the proximal end of the pressure sensor device via the patch cable 824, also moves laterally away from the distal end 822 as it extends distally from the distal end 822. Although the distal end 822 of the body 820 is illustrated as including a sharp tip while the distal end 816 of the needle 802 is illustrated as being blunt, it should be understood by those skilled in the art that the needle 802 or the pressure sensing device 806 may include a sharp tip for piercing the wall of the portal vein to gain access to the portal vein, as previously described with respect to the systems 200 and 400.

[0081] In the first configuration, a portion of the pressure sensor 812 partially blocks the distal opening 854 of the working channel 852. In one embodiment, when it is desired to insert an additional tool 860 through the working channel 852, the physician or other user may utilize a mechanism coupled to the handle portion of the pressure sensing device 806 (e.g., a pull wire or spring-loaded mechanism connected to the wiring cable 824) to control the movement of the pressure sensor 812 from the first configuration to the second configuration. Alternatively, a mechanical switch or sensor extending along the working channel 852 may be utilized to automatically move the pressure sensor 812 from the first configuration toward the second configuration (or vice versa), such that when the additional tool 860 is moved distally through the working channel 852, the mechanical switch or sensor is triggered to cause the pressure sensor 812 to move distally beyond the distal end 822 toward the second configuration by distal movement of the wiring cable 824 relative to the body 820. In the second configuration, the pressure sensor 812 is moved distally beyond the distal end 822 of the body 820, thereby extending laterally relative to the longitudinal axis of the pressure sensing device 806. In other words, when the pressure sensor 812 is moved distally beyond the distal end 822, the patch cable 824 bends, causing the pressure sensor 812 to fall in a direction away from the longitudinal axis of the pressure sensing device 806, thereby providing an unobstructed path into the portal vein for the additional tool 860. In one embodiment, the patch cable 824 can have shape memory properties such that when the pressure sensor 812 is pushed out of the body 820, the patch cable 824 bends toward a predetermined configuration.

[0082] When the additional tool 860 is removed from the working channel 852, the pressure sensor 812 can be manually pulled backward into the body 820 toward the first configuration, or alternatively, the pressure sensor 812 can be automatically pulled backward into the body 820 using a mechanical switch or sensor that is triggered when the additional tool 860 is moved proximally through the working channel 852.

[0083] like Figure 22-Figure 25As shown in , a system 900 according to another exemplary embodiment of the present disclosure may be substantially similar to system 800, including a needle 902 and a pressure sensing device 906. As described above, the portal vein may be punctured using one of the needle 902 and the pressure sensing device 906, and thus the pressure of the portal vein may be measured using the sensor 912 of the pressure sensing device 906 inserted into the portal vein. The pressure sensing device 906 may be substantially similar to the pressure sensing device 806, including a body 920 having a working channel 952 extending longitudinally therefrom to allow an additional tool 960 to be inserted therethrough to access the portal vein. Similar to the pressure sensing device 806, in a first configuration, the pressure sensor 912 blocks a portion of the distal opening 954 of the working channel 952, and thus the pressure sensor 912 must be moved toward the second configuration to allow the additional tool 960 to pass through the working channel 952 and enter the portal vein. However, in the second configuration, rather than being moved distally beyond the distal end 922 of the body 920 , the pressure sensor 912 is positioned within a correspondingly sized and shaped cavity 956 formed along the inner surface of the body 920 and positioned accordingly.

[0084] Specifically, Figure 22-Figure 23 As shown in , the pressure sensing device 906 is formed by a longitudinally extending body 920, and a working channel 952 extends through the body 920 in a manner generally parallel to the longitudinal center axis of the body 920. The pressure sensor 912 is located at the distal end 922 of the body 920 and is connected to the proximal end of the pressure sensing device 906 via a wiring cable 924 that extends longitudinally through the body 920. The wiring cable 924 may also extend in a manner generally parallel to the longitudinal center axis of the body 920. The wiring cable 924 and the pressure sensor 912 are in a longitudinally fixed position relative to the body 920. However, the pressure sensor 912 is laterally movable relative to the longitudinal center axis of the body 920. Specifically, the body 920 includes a cavity 956 that is sized and shaped to correspond to the pressure sensor 912. The cavity 956 is axially aligned with the pressure sensor 912 so that when the pressure sensor 912 is moved toward the second configuration, the pressure sensor 912 falls into the cavity 956 and / or is pushed into the cavity 956 to provide an unobstructed path for inserting an additional tool 960 into the portal vein via the working channel 952.

[0085] In one embodiment, the pressure sensor 912 may include a housing or shell 958 that is movably connected to the wiring cable 924. The housing 958 can slide laterally relative to the wiring cable 924 between a first configuration and a second configuration. Specifically, the housing 958 may include a groove or track 959, such as Fig.25As shown in FIG. 1 , the distal end 925 of the wiring cable 924 can slide within the groove or track to allow the pressure sensor 912 to move between the first configuration and the second configuration, as shown in FIG. Fig.24 The distal end 925 may include an enlarged end that is received within the track 959 to prevent the patch cable 924 from being inadvertently separated from the housing 958.

[0086] In one embodiment, the pressure sensor 912 can be biased toward the first configuration. When the additional tool 960 is inserted distally through the working channel 952 of the body 920, the distal end 962 of the additional tool 960 can be pushed against the rounded edge of the housing 958, thereby pushing the pressure sensor 912 toward the second configuration into the cavity 956, thereby allowing the additional tool 960 to move distally beyond the cavity 956 into the portal vein. When the additional tool 960 is removed, the pressure sensor 912 can return to its biased first configuration.

[0087] As discussed above with respect to system 100-900, the pressure sensing device can be guided to the portal vein under the guidance of endoscopic ultrasound (EUS). In some cases, the above-mentioned portal vein pressure sensing device may also include another sensor capable of magnetically driven tracking and / or mapping. This feature can be particularly useful if the pressure measuring device 606 is used without ultrasound, or for the purpose of training, the spatial position of the line in the anatomical structure is verified during endoscopic ultrasound surgery. Alternatively or in addition, a magnetically driven or fiber optic 3D shaping sensor can be added as an additional control to track the sharp top of the pressure sensing device, needle, or stylet for obtaining access to the portal vein during surgery. The information provided to the user (e.g., a doctor) can be used as a safety feedback to ensure that the opposite side of the vein (i.e., the far wall of the portal vein) will not be accidentally pierced.

[0088] It will be apparent to those skilled in the art that various modifications can be made in the present disclosure without departing from the scope of the disclosure.

Claims

1. A system for measuring pressure in a vein, comprising: a needle sized and shaped to be inserted through a working channel of an endoscope, the needle extending longitudinally and including a channel extending longitudinally therethrough; as well as a pressure sensing device comprising a longitudinally extending body sized and shaped to be slidably inserted through the passage of the needle and a sensor mounted at a distal end of the body and connected to a proximal end of the pressure sensing device via a wiring cable, the sensor being configured to detect information corresponding to the pressure of blood flow through the vein, wherein the pressure sensing device is longitudinally movable relative to the needle between an insertion configuration in which the sensor is covered by a portion of the needle and a pressure sensing configuration in which a distal end of the body of the pressure sensing device extends distally beyond the distal end of the needle to expose the sensor to fluid flow inside a vein, and Wherein the distal end of the body includes a fin, the fin being configured to engage with an engagement feature of the needle to define a maximum distance that the body can extend from the distal end of the needle in the pressure sensing configuration.

2. The system of claim 1, further comprising a stylet sized and shaped to be inserted through the channel of the needle, the stylet being movable longitudinally relative to the needle between the insertion configuration and the piercing configuration.

3. The system of claim 1, wherein: The sensor is mounted in a recess that extends laterally into the body of the pressure sensing device along a distal end of the body of the pressure sensing device.

4. The system of claim 1, wherein: The body of the pressure sensing device includes a through hole extending laterally through a distal end of the body such that a distal face of the sensor is exposed to fluid flow through the through hole.

5. The system of claim 1, wherein: When in the pressure sensing configuration, the distal end of the body is configured to move distally beyond the distal end of the needle a predetermined distance, and the fin is configured to engage a portion of the needle to prevent the body from being pulled proximally into the needle.

6. The system of claim 1, wherein: The sensor is connected to the pressure sensing device via the connection cable such that the sensor is configured to move distally beyond the distal end of the body when the pressure sensing device is in the pressure sensing configuration.

7. The system of claim 6, wherein: When in the pressure sensing configuration, the pressure sensor is configured to be offset from a longitudinal axis of the pressure sensing device.

8. The system of claim 1, wherein: The fin is configured to move from a first configuration in which the fin is constrained toward the outer surface of the body to a second configuration in which the fin moves radially outward to engage with a portion of the needle when the body moves distally a predetermined distance beyond the distal end of the needle.

9. The system of claim 8, wherein: The engagement feature is configured to engage the fin when the fin is in the second configuration, and the position of the engagement feature is selected to ensure that the body does not extend distally beyond the needle beyond the predetermined distance.

10. The system of claim 9, wherein: The engagement feature is one of a groove or a channel formed in the needle.

11. The system of claim 8, wherein: The fin is movable from the second configuration to the first configuration by a pull wire connected to the fin.

12. The system of claim 8, wherein: The interior of the needle is configured to interact with the fin such that the fin is movable from the second configuration to the first configuration when the body is proximally withdrawn into the needle.

13. The system of claim 12, wherein: The inner surface of the needle includes an inclined surface at a distal end thereof, the inclined surface configured to move the fins from the second configuration to the first configuration when the body is withdrawn proximally into the needle.

14. The system of claim 1, wherein: The needle is flexible.

15. The system of claim 1, wherein: The patch cable extends proximally from the sensor through the length of the body.

16. The system of claim 1, wherein: The fin includes two fins, which are respectively located on two sides of the main body of the pressure sensing device.

17. The system of claim 1, wherein: The fin is located on an outer surface of the body of the pressure sensing device and the engagement feature is located on an inner surface of the channel of the needle.

Images