SENSOR DEVICE AND METHODS OF OPERATION FOR A CATHETER BASED TREATMENT OF MYOCARDIAL MICROVASCULAR OBSTRUCTION

Abstract

Sensor devices and methods of operating for use with catheter-based treatments of microcardial microvascular obstruction by infusion of fluids having protective agents into vasculature are provided herein. Such catheter devices can include a first lumen configured for advancement over a guidewire and for passage of fluid having protective agents after removal of the guidewire and a second lumen for inflation of an angioplasty balloon and can further include a temperature and/or pressure sensor mounted on the catheter body. Such catheter devices can further include use of a distal occlusive membrane between the angioplasty balloon and distal end to facilitate infusion into microvasculature. The occlusive membrane can be deployed by relative movement of concentric channels, thereby reducing the need for additional lumen while optimizing the size of the catheter device and lumens.

Claims

1. A pressure sensor device comprising: a pressure sensor configured for monitoring a pressure within a coronary artery during a treatment of myocardial microvascular obstruction in a patient, wherein the pressure sensor device is configured for mounting at or near a distal end of a working channel of a catheter through which a fluid having protective agents is injected during the treatment.

2. The pressure sensor device of claim 1, wherein the pressure sensor comprises a pressure sensor element, and the pressure sensor device further comprises: a holder configured to support the pressure sensing element, wherein the holder is configured to fixedly couple the pressure sensor to a distal end of a catheter suitable for treatment of myocardial microvascular obstruction; and an electrical connector that receives a signal from the pressure sensing element corresponding to a pressure detected by the pressure sensing element.

3. The pressure sensor device of claim 2, wherein the holder is substantially rigid such that the pressure sensing element is held in a substantially fixed position at the distal end of the catheter.

4. The pressure sensor device of claim 2, wherein the pressure sensor is configured for operation in a fluid-filled vascular environment.

5. The pressure sensor device of claim 2, wherein the pressure sensor is configured for detection of whether a systolic blood pressure drops below 90 mm Hg.

6. The pressure sensor device of claim 2, wherein the pressure sensor is configured to detect at least a range of pressures between 50-200 mm Hg.

7. The pressure sensor device of claim 2, wherein the pressure sensor is of a size suitable for mounting on the distal end of a catheter sized for vascular delivery through a coronary artery.

8. The pressure sensor device of claim 7, wherein the pressure sensor has a cross-section width perpendicular to the axis of the catheter when the pressure sensor is mounted thereon, wherein the width is 3 mm or less so as to facilitate detection of a pressure within the vascular without blocking a working channel of the catheter to allow inhibited flow of fluid having protective agents therethrough.

9. The pressure sensor device of claim 2, wherein the pressure sensor is also a temperature sensor.

10. A treatment catheter for treatment of myocardial microvascular obstruction comprising: a working channel; an occlusion membrane; a balloon inflation lumen; a balloon; a pressure sensor as in claim 1 mounted at or close to the distal end of the working channel; two concentric channels configured to control the occlusion membrane; and a pressure seal distal to the balloon.

11. The catheter of claim 10 wherein any of or combination of: the working channel is configured and sized to accommodate a guidewire and serve as a working channel for drug delivery; a stent is disposed over the balloon; the pressure sensor is also a temperature sensor; and a space between the two concentric channels that control the sealing membrane serves as a gas transmission space for controlling the inflation of the balloon.

12. The catheter of claim 10 further comprising: a controller operably coupled to the sensor device and operably coupled to the catheter, the controller having programmable instructions recorded on a memory thereof configured for controlling operation of the catheter based on a sensor output received from the sensor.

13. The catheter of claim 10 further comprising: an electrical cable connected to the pressure sensor and extending to a proximal end of the catheter, wherein the electrical cable extends through the working channel or extends along an outer surface of the working channel.

14. A method of operating a pressure sensor for treatment of myocardial obstruction of a patient, the method comprising: obtaining a first signal from a pressure sensor disposed at or near a distal end of a catheter disposed in a coronary artery advanced beyond an ischemic lesion in response to a first input that faciliates inflating of a balloon of the catheter, wherein the first signal corresponds to a first pressure after inflating a balloon of the catheter to confirm complete blocking of the coronary artery; obtaining a second signal from the pressure sensor in response to a second input that facilitates injecting a therapeutic agent into the coronary artery between the balloon and the myocardium; and obtaining a third signal from the pressure sensor during continued injecting of the therapeutic agent into the coronary artery between the balloon and the myocardium thereby facilitating injection of the therapeutic agent at a controlled pressure.

15. The method of claim 14, further comprising: obtaining one or more additional signals from the pressures sensor over time in response to the second input injecting the therapeutic agent into the coronary artery between the balloon and the myocardium thereby facilitating injection of the therapeutic agent at a controlled pressure.

16. The method of claim 14, wherein obtaining the third signal is based on a third input adjusting a rate or pressure of injection of the therapeutic agent in response to the pressure determined from the second signal.

17. The method of claim 16, wherein the first and second signals are obtained automatically with a controller communicatively coupled to the pressure sensor in response to the first and second inputs.

18. The method of claim 17, wherein the wherien the first and second inputs are automatically controlled by the controller.

19. The method of claim 14, further comprising: obtaining a fourth signal from the pressure sensor based on a fourth input that facilitates deflating the balloon and restoring blood flow through the artery.

20. A catheter device for delivering and infusing protective agent delivery into microvasculature, the device comprising: an elongate catheter body having a proximal end and a distal end; a first lumen extending between from a proximal opening to a distal opening, the proximal opening being at or near the proximal end and the distal opening being at or near the distal end, wherein the first lumen configured for delivery of a guidewire and delivery of the protective agent after guidewire removal; a distal angioplasty balloon disposed on a distal portion of the catheter body proximal of the distal end; a second lumen extending between the proximal end and the distal portion, the second lumen being communicatively coupled with the distal angioplasty balloon to facilitate inflation of the distal angioplasty balloon; a sensor mounted on the elongate catheter body and disposed at or along the distal portion of the elongate catheter body; and a control unit configured to control operation of the catheter device based on a sensor output received from the sensor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG. 1 shows an exemplary catheter device in accordance with some embodiments.

[0022] FIGS. 2A-2C shows detail cross-section view of exemplary catheter devices in accordance with some embodiments.

[0023] FIG. 3 shows a detail view of the occlusion membrane deployed in accordance with some embodiments.

[0024] FIG. 4 shows a schematic of a catheter control system with pressure sensor in accordance with some embodiments.

DESCRIPTION OF THE INVENTION

[0025] In a first aspect, the invention pertains to an improved sensor integrated within a catheter configuration that reduces the size of the catheter, improving its ability to reach the target area, while at the same time increasing the bore size through which the infusate is supplied, allowing a reduction in infusion pressure to achieve the same volume infusion. In another aspect, the invention utilizes a flexible pressure-sealing membrane to isolate the blood flow from the primary feeder vessel to the microvasculature. This maintains a pressure gradient down which the infusate flows, ensuring its delivery to the microvasculature.

[0026] Starting with the first aspect, some conventional catheters include three lumens, an inflation lumen, infusion lumen and Rx lumen, while other conventional catheters utilize four lumens. In some treatment methods using such catheters, the guidewire is first inserted through the coronary artery lesion and into the space between the lesion and the heart wall. Then, the guidewire is threaded into the infusion lumen and advanced to the end of the guidewire, at which time infusate is introduced into the anatomy distal to the stent balloon and/or occlusion balloon via the Rx lumen. In order to reach the affected vasculature, the entire catheter is of necessity quite small; commercial drug-infusing microcatheters are often one millimeter in diameter or less. Some conventional catheters utilize three or four lumens to accommodate one or two balloon inflation lines, the guidewire and infusion. It is thus clear that the infusion port in a four-lumen system would have to be quite small in diameter.

[0027] Although some conventional methods make use of a temperature and/or pressure sensing guidewire, with the sensors placed distal to the angioplasty and/or occlusion balloon, In one aspect of this invention, the catheter makes use of a pressure and/or temperature sensor mounted on or near the distal tip of the catheter, specifically adjacent the working channel where the fluid having protective agents is dispensed from, rather than in the guidewire. While some have suggested catheter-mounted sensors, the manner in which the sensors are attached, positioned and operated is not well described and is in need of further improvements. Such improvements are described further below.

[0028] In some embodiments, the method includes first steering a standard guidewire, without embedded sensors, to correct placement within the coronary feeder vessel. The catheter is guided into place after threading the guidewire onto the lumen. Then the guidewire is withdrawn, followed by inflating the angioplasty balloon (with or without a stent as required). While this balloon or the separate occlusion balloon is inflated, the cardioprotective agent is then introduced through the same lumen that accommodated the guidewire.

[0029] The advantages of this method are twofold. First, standard guidewires are both less expensive and, by reputation, easier to steer than pressure and temperature-sensing guidewires. Second, by using the method in which the guidewire is withdrawn before infusion, the need for an additional, specific infusion lumen is avoided, because the guidewire lumen can be used to inject the infusate after the guidewire has been withdrawn. Thus each of the lumens can be made larger, reducing the amount of pressure required to achieve a desired level of flow. The second aspect of the invention pertains to an improved catheter sensor configuration that allows a superior pressure profile to be achieved within the coronary artery during infusion.

[0030] The present invention further provides an alternative, less expensive means of controlling pressure in between the occlusion balloon and the myocardium. In some embodiments, the occlusion balloon described in the existing literature remains as a component in the invention described here, but can be supplemented with additional hardware to improve the safety and efficacy of the drug delivery system.

[0031] Some conventional catheters include a separate occlusion balloon in addition to the stent balloon. By implication, a separate balloon, with different properties than the stent balloon, is better suited to performing the desired occlusion than using the stent balloon for this purpose. In one aspect of the invention, this specific occlusion balloon is replaced with a filter membrane. Utilizing a membrane occlusion system provides marked benefits over a balloon occlusion system. Briefly, the flexible membrane, in contrast to the balloon, provides a flexing motion in response to arterial movement and thus maintains an advantageous pressure gradient between the delivery port of the catheter and the microvasculature to be served. This helps to force open the microvessels during diastole, improving uptake of the cardioprotective agent.

[0032] In another aspect, the pressure driving against the myocardium can be adjusted by adjusting the degree of occlusion by the occlusion balloon. In some embodiments, this can be accomplished either by an open-loop system in which the practitioner simply reads out the pressure from the pressure sensor on the distal end of the catheter or by a closed-loop system in which a targeted pressure is achieved by a balloon inflation controller that reads out the information from the pressure sensor.

[0033] FIG. 1 shows an exemplary catheter 100 that includes a working channel 3, which both accommodates a guidewire (not shown) as well as allowing infusion of a therapeutic fluid having cardioprotective agents distal of the occlusion membrane 8. The catheter can further include a balloon inflation lumen (e.g., a space 2 between channel 4 and channels 5, 6) in fluid communication with a balloon 7, and optionally a stent 9 over the balloon 7 (if necessary for a given procedure).

[0034] The catheter contains a distal pressure sensor 10 mounted close to the distal end of the working channel 3. The term close can be interpreted to mean within any of: 4 or less, 2 or less, 1 or less, 0.5 or less, 0.2 or less, or 0.1 or less. The pressure sensor 10 can be disposed just within the working channel, just outside of the working channel or precisely at the distal end. The pressure sensor 10 is powered and communicatively coupled through an electrical cable 11 that extends from the pressure sensor to a proximal end of the catheter. As can be seen in the cross-sections A-A shown in FIGS. 2A-2C, the electrical cable can extend within the working channel 3 (see FIG. 2A), can extend along the outer surface of the channel or catheter (both alternate positions shown in FIG. 2B), or can be embedded within a wall of a component of the catheter (see FIG. 2C). In some embodiments, the pressure sensor 10 can also be a temperature sensor. Control of the membrane 8 can be achieved using two concentric channels 3 and 4; in this case, the space between the channels 4 and channels 5,6 can serve as the inflation channel for balloon inflation. It is appreciated that the membrane can be deployed by any suitable approach. A pressure seal 2 distal to the balloon between 4 and 6 maintains the pressure in the balloon 7. It is appreciated that, in some embodiments, the pressure seal could be disposed elsewhere, such as within the balloon or proximal of the balloon, or any suitable location.

[0035] Pressure sensor 10 includes a pressure sensing element 10A that can include a pressure sensing means (e.g. deformable membrane) and a signal detector that detects variations in electrical signals from the pressure sensing means in response to changes in pressure. The pressure sensing element 10A is supported by holder 10B, which is suited or configured to be mounted to the catheter at or near the distal end of the working channel without increasing the delivery profile of the catheter and without inhibiting fluid flow through the working channel. In some embodiments, the holder 10B is rigid or semi-rigid so as to secure the pressure sensing element 10 adjacent the working channel during injection of the fluid having protective agents. In some embodiments, the holder 10B is specially shaped (e.g. curved, notched, angled) and/or configured to suspend the pressure sensing element 10A at or near the distal end opening of the working channel and inhibit lateral movement of the sensor from fluid flow during injection of the therapeutic agent. In some embodiments, holder 10B can be a substrate of the pressure sensing element. Pressure sensor 10 further includes an electrical connector 10C having electrical contacts that is electrically connected to the signal detection means of the pressure sensor 10 and can be connected to electrical cable 11 to facilitate control and communication of the pressure sensor 10 from a proximal end of the catheter, typically by a controller operably coupled to the catheter device.

[0036] FIG. 4 shows an exemplary system setup by which the sensor device 10 described above can be utilized in a catheter system to facilitate treatment of myocardial microvascular obstruction. Controller 20 is operably connected to a catheter device 23 and a sensor 21 incorporated into the catheter device 23, for example as described above. Controller 20 is configured to obtain sensor input signals 22 from the pressure sensor by which the controller operates the catheter device (e.g. inflation/deflation of balloon, deployment of a seal, adjustment of fluid injection, etc.). In some embodiments, controller 20 is configured to initiate injection of a therapeutic agent through the working channel of the catheter device 23 and adjust injection based on the pressure sensor input signals 22 obtained from the pressure sensor 21. In some embodiments, the injection utilizes sensor feedback to ensure an appropriate range of pressure is maintained during injection.

[0037] The methods to use these device includes first steering a standard guidewire, without embedded sensors, to correct placement within the coronary feeder vessel. The catheter is guided into place after threading the guidewire onto the lumen 3. Then the guidewire is withdrawn, followed by inflating the angioplasty balloon 7 (with or without a stent 9 as required) through the inlet 1, which directs pressurized fluid via the space between channels 4 and 5 to the balloon 7. The membrane 8 is then manipulated via relative motion of channels 3 and 4 into its open, deployed configuration, as shown in FIG. 3, so as to contact the inside of the vasculature V. The balloon 7 is then deflated, allowing systolic pressure to reach the proximal side of membrane 8. The therapeutic agent TA having cardioprotective agents is then introduced through working channel 3. As the heart beats, the deformation of the deployed membrane 8 pushes the infusate towards the myocardium.

[0038] In the foregoing specification, the invention is described with reference to specific embodiments thereof, but those skilled in the art will recognize that the invention is not limited thereto. Various features, embodiments and aspects of the above-described invention can be used individually or jointly. Further, the invention can be utilized in any number of environments and applications beyond those described herein without departing from the broader spirit and scope of the specification. The specification and drawings are, accordingly, to be regarded as illustrative rather than restrictive. It will be recognized that the terms comprising, including, and having, as used herein, are specifically intended to be read as open-ended terms of art. Each of the references cited herein are incorporated herein by reference for all purposes.