FLUID INJECTION LINE CONTAMINATION INHIBITOR FOR INTRAVASCULAR CATHETER SYSTEM

RELATED APPLICATION

[0001 ] This application claims priority on U.S. Provisional Application Serial No. 62/523,650, filed on June 22, 2017, and entitled "REFRIGERANT PATH CONTAMINATION INHIBITOR SYSTEM FOR CRYOGENIC BALLOON CATHETER ASSEMBLY." As far as permitted, the contents of U.S. Provisional Application Serial No. 62/523,650 are incorporated herein by reference.

BACKGROUND

[0002] Cardiac arrhythmias involve an abnormality in the electrical conduction of the heart and are a leading cause of stroke, heart disease, and sudden cardiac death. Treatment options for patients with arrhythmias include medications, implantable devices, and catheter ablation of cardiac tissue.

[0003] Catheter ablation involves delivering ablative energy to tissue inside the heart to block aberrant electrical activity from depolarizing heart muscle cells out of synchrony with the heart's normal conduction pattern. The procedure is performed by positioning a portion, such as a tip, of an energy delivery catheter adjacent to diseased or targeted tissue in the heart. One form of energy that is used to ablate diseased heart tissue includes cryogenics (also referred to herein as "cryoablation"). During this procedure, the tip of the catheter is positioned adjacent to targeted cardiac tissue, at which time energy is delivered to create tissue necrosis, rendering the ablated tissue incapable of conducting electrical signals.

[0004] The dose of the energy delivered is an important factor in increasing the likelihood that the treated tissue is permanently incapable of conduction. At the same time, delicate collateral tissue, such as the esophagus, the bronchus, and the phrenic nerve surrounding the ablation zone can be damaged and can lead to undesired complications. Thus, the operator must finely balance delivering therapeutic levels of energy to achieve intended tissue necrosis while avoiding excessive energy leading to collateral tissue injury.

[0005] Atrial fibrillation is one of the most common arrhythmias treated using cryoablation. In the earliest stages of the disease, paroxysmal atrial fibrillation, the treatment strategy involves isolating the pulmonary veins from the left atrial chamber. Recently, the use of techniques known as "balloon cryotherapy" catheter procedures to treat atrial fibrillation have increased. During the balloon cryotherapy procedure, a cryogenic fluid (such as nitrous oxide, or any other suitable fluid) is delivered under pressure to an interior of one or more cryogenic balloons which are positioned against the targeted tissue. Using this method, the extremely frigid cryogenic fluid causes necrosis of the targeted tissue, thereby rendering the ablated tissue incapable of conducting unwanted electrical signals.

[0006] Cryoablation procedures use high pressure cryogenic fluid injected into the catheter from a control console to create cooling at the targeted cardiac tissue. In order to ensure that the cryogenic fluid is in liquid state, it passes through a fluid injection line, including small diameter tubes, and one or more subcoolers. Since the subcoolers operate at temperatures that are subzero degrees Celsius, any humidity in the fluid injection line from the environment or any other source can freeze and cause blockages in the intravascular catheter system obstructing the path of the cryogenic fluid. For example, the intravascular catheter system generally includes fluid injection lines and/or connection ports with very small diameters. Any debris or contaminates that enter the fluid injection line at the control console or connection ports, or any other location, will likely be injected into the catheter, causing blockages which can result in either a fully blocked or partially blocked path. Under these conditions, the procedure cannot be executed and the intravascular catheter system must be shut down until the subcooler warms up and the ice buildup melts. This delay causes interrupted procedures, which increases risk to the patient.

SUMMARY

[0007] The present invention is directed toward a fluid injection line contamination inhibitor (sometimes referred to herein as "contamination inhibitor") for an intravascular catheter system (sometimes referred to herein as "catheter system"). The catheter system is used during a cryoablation procedure. The catheter system can include a fluid source, a subcooler that is downstream from the fluid source and a fluid injection line. In certain embodiments, the contamination inhibitor can include a first check valve that is in fluid communication with the fluid source. In some embodiments, the first check valve can be positioned along the fluid injection line downstream from the subcooler. The first check valve can be configured to inhibit contaminants in the fluid injection line from moving upstream to near the subcooler.

[0008] In various embodiments, the catheter system can further include a handle assembly that is in fluid communication with the fluid source. The first check valve can be positioned between the handle assembly and the subcooler.

[0009] In certain embodiments, the catheter system can include a connection port that is positioned between the handle assembly and the subcooler. The first check valve can be positioned between the connection port and the subcooler. In one embodiment, the first check valve can be positioned near the connection port. In another embodiment, the first check valve can be positioned at the connection port.

[0010] In some embodiments, the contamination inhibitor can also include a second check valve that is in fluid communication with the fluid source. In some embodiments, the second check valve can be positioned along the fluid injection line downstream from the subcooler and the first check valve. The second check valve can also be configured to inhibit contaminants in the fluid injection line from moving upstream to near the subcooler.

[0011 ] In certain embodiments, the second check valve can be positioned between the handle assembly port and the subcooler. In one embodiment, the second check valve can be positioned between the handle assembly and the connection port. In another embodiment, the second check valve can be positioned at the connection port and the subcooler.

[0012] The present invention is also directed toward a method for inhibiting contaminants from moving upstream in a fluid injection line of a catheter system to near a subcooler by positioning a first check valve along the fluid injection line downstream from the subcooler. In one embodiment, the step of inhibiting can include positioning the first check valve between the subcooler and a handle assembly. In another embodiment, the step of inhibiting can include positioning the first check valve near a connection port. The connection port can be positioned between the handle assembly and the subcooler. In still another embodiment, the step of inhibiting can include positioning the first check valve at the connection port.

[0013] In some embodiments, the method can further comprise the step of inhibiting contaminants from moving upstream in the fluid injection line to near the subcooler by positioning a second check valve along the fluid injection line downstream from the subcooler and the first check valve. In one embodiment, the step of inhibiting can include positioning the second check valve between the handle assembly and the connection port. In an alternative embodiment, the step of inhibiting can include positioning the second check valve between the connection port and the subcooler.

[0014] The present invention can also be directed toward a contamination inhibitor for a catheter system. The catheter system can include a fluid source, a handle assembly, a subcooler that is downstream from the fluid source, a fluid injection line and a connection port that is positioned between the handle assembly and the subcooler. In various embodiments, the contamination inhibitor can include a first check valve and a second check valve that are in fluid communication with the fluid source. In some embodiments, the first check valve can be positioned along the fluid injection line between the subcooler and the connection port. In other embodiments, the second check valve can be positioned along the fluid injection line downstream from the subcooler and the first check valve. Both the first check valve and the second check valve can be configured to inhibit contaminants in the fluid injection line from moving upstream to near the subcooler.

[0015] In one embodiment, the first check valve can be positioned near the connection port and the second check valve can be positioned at the connection port. In another embodiment, first check valve can be positioned near the connection port and the second check valve can be positioned between the handle assembly and the connection port. In still another embodiment, the first check valve can be positioned at the connection port and the second check valve can be positioned between the handle assembly and the connection port.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The novel features of this invention, as well as the invention itself, both as to its structure and its operation, will be best understood from the accompanying drawing, taken in conjunction with the accompanying description, in which similar reference characters refer to similar parts, and in which:

[0017] Figure 1 is a schematic side view of a patient and one embodiment of an intravascular catheter system including a fluid injection line contamination inhibitor having features of the present invention.

DESCRIPTION

[0018] Embodiments of the present invention are described herein in the context of a fluid injection line contamination inhibitor. Those of ordinary skill in the art will realize that the following detailed description of the present invention is illustrative only and is not intended to be in any way limiting. Other embodiments of the differential pressure limiter will readily suggest themselves to such skilled persons having the benefit of this disclosure. Reference will now be made in detail to implementations of the present invention as illustrated in the accompanying drawings.

[0019] In the interest of clarity, not all of the routine features of the implementations described herein are shown and described. It will, of course, be appreciated that in the development of any such actual implementation, numerous implementation-specific decisions must be made in order to achieve the developer's specific goals, such as compliance with application-related and business-related constraints, and that these specific goals will vary from one implementation to another and from one developer to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking of engineering for those of ordinary skill in the art having the benefit of this disclosure.

[0020] Although the disclosure provided herein focuses mainly on cryogenics, it is understood that various other forms of energy can be used to ablate diseased heart tissue. These can include radio frequency (RF), ultrasound and laser energy, as non-exclusive examples. The present invention is intended to be effective with any or all of these and other forms of energy.

[0021 ] Figure 1 is a schematic side view of one embodiment of an intravascular catheter system 10 (also sometimes referred to herein as a "catheter system") for use with a patient 12, which can be a human being or an animal. Although the catheter system 10 is specifically described herein with respect to an intravascular catheter system, it is understood and appreciated that other types of catheter systems and/or ablation systems can equally benefit by the teachings provided herein. For example, in certain non-exclusive alternative embodiments, the present invention can be equally applicable for use with any suitable types of ablation systems and/or any suitable types of catheter systems. Thus, the specific reference herein to use as part of the intravascular catheter system is not intended to be limiting in any manner.

[0022] The design of the catheter system 10 can be varied. In certain embodiments, such as the embodiment illustrated in Figure 1 , the catheter system 10 can include one or more of a control system 14, a fluid source 16, a balloon catheter 18, a handle assembly 20, a control console 22, a graphical display 24, one or more subcoolers 26 (only one subcooler 26 is illustrated in Figure 1 for clarity), a fluid injection line 28 and a fluid injection line contamination inhibitor 30 (also sometimes referred to herein as a "contamination inhibitor"). It is understood that although Figure 1 illustrates the structures of the catheter system 10 in a particular position, sequence and/or order, these structures can be located in any suitably different position, sequence and/or order than that illustrated in Figure 1 . It is also understood that the catheter system 10 can include fewer or additional components than those specifically illustrated and described herein. [0023] In various embodiments, the control system 14 is configured to monitor and control the various processes of a cryoablation procedure. More specifically, the control system 14 can control release and/or retrieval of a cryogenic fluid 31 to and/or from the balloon catheter 18. In certain embodiments, the control system 14 can control various structures described herein that are responsible for maintaining and/or adjusting a flow rate and/or fluid pressure of the cryogenic fluid 31 that is released to the balloon catheter 18 during the cryoablation procedure. In such embodiments, the catheter system 10 delivers ablative energy in the form of the cryogenic fluid 31 to cardiac tissue of the patient 12 to create tissue necrosis, rendering the ablated tissue incapable of conducting electrical signals. Additionally, in various embodiments, the control system 14 can control activation and/or deactivation of one or more other processes of the balloon catheter 18 described herein. Further, or in the alternative, the control system 14 can receive data and/or other information (hereinafter sometimes referred to as "sensor output") from various structures within the catheter system 10. In some embodiments, the control system 14 can assimilate and/or integrate the sensor output, and/or any other data or information received from any structure within the catheter system 10. Additionally, or in the alternative, the control system 14 can control positioning of portions of the balloon catheter 18 within the body of the patient 12, and/or can control any other suitable functions of the balloon catheter 18.

[0024] The fluid source 16 contains the cryogenic fluid 31 , which is delivered to the balloon catheter 18 with or without input from the control system 14 during the cryoablation procedure. The type of cryogenic fluid 31 that is used during the cryoablation procedure can vary. In one non-exclusive embodiment, the cryogenic fluid 31 can include liquid nitrous oxide. In another non-exclusive embodiment, the cryogenic fluid 31 can include liquid nitrogen. However, any other suitable cryogenic fluid 31 can be used. It is understood that although the embodiment illustrated in Figure 1 focuses on delivery of the cryogenic fluid 31 to the balloon catheter 18 (as indicated by directional arrows 32A-E), the cryogenic fluid 31 is also retrieved, vented or exhausted (typically in a gaseous state). However, the retrieval of the cryogenic fluid 31 is not shown in Figure 1 for the sake of clarity.

[0025] The design of the balloon catheter 18 can be varied to suit the specific requirements of the catheter system 10. As shown, the balloon catheter 18 is inserted into the body of the patient 12 during the cryoablation procedure. In one embodiment, the balloon catheter 18 can be positioned within the body of the patient 12 using the control system 14. Stated in another manner, the control system 14 can control positioning of the balloon catheter 18 within the body of the patient 12. Alternatively, the balloon catheter 18 can be manually positioned within the body of the patient 12 by a health care professional (also sometimes referred to herein as an "operator"). As used herein, health care professional and/or operator can include a physician, a physician's assistant, a nurse and/or any other suitable person and/or individual. In certain embodiments, the balloon catheter 18 is positioned within the body of the patient 12 utilizing at least a portion of the sensor output received from the balloon catheter 18. For example, in various embodiments, the sensor output is received by the control system 14, which can then provide the operator with information regarding the positioning of the balloon catheter 18. Based at least partially on the sensor output feedback received by the control system 14, the operator can adjust the positioning of the balloon catheter 18 within the body of the patient 12 to ensure that the balloon catheter 18 is properly positioned relative to targeted cardiac tissue. While specific reference is made herein to the balloon catheter 18, as noted above, it is understood that any suitable type of medical device and/or catheter may be used.

[0026] The handle assembly 20 is handled and used by the operator to operate, position and/or control the balloon catheter 18. The design and specific features of the handle assembly 20 can vary to suit the design requirements of the catheter system 10. In the embodiment illustrated in Figure 1 , the handle assembly 20 is separate from, but in electrical and/or fluid communication with the control system 14, the fluid source 16, the graphical display 24, the subcooler(s) 26 and/or the contamination inhibitor 30. In some embodiments, the handle assembly 20 can integrate and/or include at least a portion of the control system 14 within an interior of the handle assembly 20. It is understood that the handle assembly 20 can include additional components than those specifically illustrated and described herein.

[0027] The control console 22 can contain one or more of the other structures of the catheter system 10. In the embodiment illustrated in Figure 1 , the control console 22 includes at least a portion of the control system 14, the fluid source 16, the graphical display 24, the subcooler(s) 26, the fluid injection line 28 and the contamination inhibitor 30. However, in alternative embodiments, the control console 22 can contain additional structures not shown or described herein. Still alternatively, the control console 22 may not include various structures that are illustrated within the control console 22 in Figure 1 . For example, in one embodiment, the control console 22 does not include the graphical display 24.

[0028] In various embodiments, the graphical display 24 is electrically connected to the control system 14. Additionally, the graphical display 24 provides the operator of the catheter system 10 with information that can be used before, during and after the cryoablation procedure. For example, the graphical display 24 can provide the operator with information based on the sensor output, and any other relevant information that can be used before, during and after the cryoablation procedure. The specifics of the graphical display 24 can vary depending upon the design requirements of the catheter system 10, or the specific needs, specifications and/or desires of the operator.

[0029] In one embodiment, the graphical display 24 can provide static visual data and/or information to the operator. In addition, or in the alternative, the graphical display 24 can provide dynamic visual data and/or information to the operator, such as video data or any other data that changes over time. Further, in various embodiments, the graphical display 24 can include one or more colors, different sizes, varying brightness, etc., that may act as alerts to the operator. Additionally, or in the alternative, the graphical display 24 can provide audio data or information to the operator.

[0030] The subcooler 26 maintains the cryogenic fluid 31 in a liquid state during delivery of the cryogenic fluid 31 to the balloon catheter 18. The subcooler 26 is in fluid communication with the fluid source 16. The design or type of subcooler 26 can be varied depending upon the design requirements of the catheter system 10. The subcooler 26 may utilize any suitable process and/or method to maintain the cryogenic fluid 31 in the liquid state. In certain embodiments, the subcooler 26 operates at relatively cold temperatures, e.g., less than zero degrees Celsius, in order to maintain the cryogenic fluid 31 in the liquid state. Consequently, any water, e.g., from humidity, or other undesirable particles, compounds, etc. (sometimes collectively referred to herein as "contaminants") that may be located within the fluid injection line 28 during any portion of the cryoablation procedure could likely be subject to freezing, thereby potentially blocking the fluid injection line 28, either partially or fully. Additionally, the subcooler 26 may be positioned at any location downstream from the fluid source 16.

[0031 ] The fluid injection line 28 is a conduit that allows the cryogenic fluid 31 to move from the fluid source 16 to the balloon catheter 18. In this embodiment, the cryogenic fluid 31 can move from the fluid source 16 to the balloon catheter 18 in a direction of directional arrows 32A-E. The fluid injection line 28 can be an uninterrupted line that extends from the fluid source 16 to the balloon catheter 18. Alternatively, the fluid injection line 28 can be interrupted, e.g., the fluid injection line 28 can have two or more delivery line segments (not shown), each of which connects one structure to another along the path from the fluid source 16 to the balloon catheter 18. For example, the handle assembly 20 may be connected to the control console 22 via one such delivery line segment. In embodiments where delivery line segments connect one structure to another, there is a potential that contaminants may enter at various connection points potentially causing clogs or blockages within the fluid injection line 28. Furthermore, the fluid injection line 28 can include a relatively small diameter tube, which may be more susceptible to potential clogging or blocking by the presence of contaminants.

[0032] The contamination inhibitor 30 inhibits or prevents contaminants from moving upstream, e.g., in a direction opposite of directional arrows 32A-E, through the fluid injection line 28 to a location near the subcooler 26 where such contaminants can freeze. Stated another way, "near the subcooler 26" can include any position along the fluid injection line 28 within the control console 22, wherein any contaminants within the fluid injection line 28 are not a sufficient distance from the subcooler 26, such that the contaminants can be subject freezing and/or clogging or blocking the fluid injection line 28.

[0033] The design or type of contamination inhibitor 30 can be varied depending upon the design requirements of the catheter system 10. In one embodiment, the contamination inhibitor 30 can include one or more check valves 34A, 34B that are in fluid communication with the fluid source. For example, Figure 1 illustrates a first check valve 34A and a second check valve 34B that is downstream from the first check valve 34A. While the embodiment illustrated in Figure 1 shows the first check valve 34A and the second check valve 34B, it is understood that the contamination inhibitor can include any number of check valves 34A, 34B, i.e., one check valve, two check valves, three check valves, etc. It is further understood that the first check valve 34A and the second check valve 34B can be used interchangeably. In other words, either check valve 34A, 34B can be referred to as the "first check valve 34A" or the "second check valve 34B." Alternatively, the contamination inhibitor 30 can include any other suitable valve or type of device that can regulate, direct or control the flow of the cryogenic fluid 31 to prevent contaminants from moving upstream through the fluid injection line 28 to a location near the subcooler(s) 26.

[0034] The design or type of the check valves 34A, 34B can also vary. The check valves 34A, 34B can include a design or type of valve that allows the cryogenic fluid 31 to flow in only one direction, e.g., in the direction of directional arrows 32A-E, but inhibits or prevents the cryogenic fluid 31 from flowing upstream. The check valves 34A, 34B can allow the cryogenic fluid 31 to flow through the fluid injection line 28 in only one direction via any suitable manner or method, such as mechanically or electrically, for example. Accordingly, the check valves 34A, 34B can be configured to inhibit contaminants within the fluid injection line 28 from moving upstream to near the subcooler(s) 26.

[0035] In various embodiments, the control console 22 and/or catheter system can include a connection port 36. As used herein, the connection port 36 can be a port that directly or indirectly connects the handle assembly 20 to the control console 22, the control system 14 or other structures of the catheter system 10. In some embodiments, the catheter system 10 may also include one or more delivery line segments. The connection port 36 can be positioned at any location between the handle assembly 20 and the subcooler(s) 26. In one embodiment, the check valves 34A, 34B can be positioned along the fluid injection line 28 at the connection port 36. As referred to herein, "at" the connection port 36 can include any position along the fluid injection line 28 within the control console 22 that is immediately adjacent to or neighboring the connection port 36. In another embodiment, the check valve 34 can be positioned along the fluid injection line 28 near the connection port 36. As referred to herein, "near the connection port 36" can include along the fluid injection line 28 within the control console 22, but away from the subcooler(s) 26, such that contaminants may be a sufficient distance from the subcooler(s) 26 to not be subject freezing, clogging or blocking the fluid injection line 28.

[0036] With this configuration, the cryogenic fluid 31 can flow through the fluid injection line 28 in one direction, while contaminants are inhibited from flowing upstream through the fluid injection line 28 between the connection port 36 and the subcooler(s) 26 and/or the control system 14. In alternative embodiments, the check valves 34A, 34B can be positioned at one or more locations other than near the connection port 36, or in addition to near the connection port 36. For example, check valves 34A, 34B can be positioned at any location downstream, i.e., toward the balloon catheter 18 or in the direction of directional arrows 32A-E, from the subcooler(s) 26, such as between the handle assembly 20 and the subcooler 26, for example. In other alternative embodiments, the check valves 34A, 34B can be positioned between the handle assembly 20 and the connection port 36 and/or the connection port 36 and the subcooler 26. In still other alternative embodiments, the check valves 34A, 34B can be positioned either inside of the control console 22, outside of the control console 22, or both inside and outside of the control console 22.

[0037] With the designs illustrated and/or described herein, the contamination inhibitor 30, i.e., check valves 34A, 34B, allows movement of the cryogenic fluid 31 within the fluid injection line 28 in accordance with the directional arrows 32A-E, while inhibiting movement of cryogenic fluid 31 and/or contaminants within the fluid injection line 28 in a direction opposite of directional arrows 32A-E.

[0038] It is understood that although a number of different embodiments of the catheter system 10 and the contamination inhibitor 30 have been illustrated and described herein, one or more features of any one embodiment can be combined with one or more features of one or more of the other embodiments, provided that such combination satisfies the intent of the present invention.

[0039] While a number of exemplary aspects and embodiments of the catheter system 10 and the contamination inhibitor 30 have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions and subcombinations thereof. It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions and sub-combinations as are within their true spirit and scope.