SELECTIVE PERFUSION DEVICE AND METHOD

Abstract

The present invention relates to a system for the selective treatment of one or more organs, said system comprising a first catheter comprising a means for occluding a first lumen downstream of said organ(s); a second catheter comprise a means for occluding a second lumen upstream of said organ(s); an extracorporeal device configured to deliver fluid through the first catheter and to receive fluid through the second catheter, and comprising means for processing the fluid. The present invention also relates to a method for the selective treatment of one or more organs.

Claims

1. A system for the selective perfusion of one or more organs, said system comprising: a first catheter including a first means for occluding a first lumen downstream of the one or more organs; a second catheter including a second means for occluding a second lumen upstream of the one or more organs; and an extracorporeal device configured to deliver fluid through the first catheter and to receive fluid through the second catheter, the extracorporeal device including a third means for processing the fluid.

2. The system according to claim 1, wherein the first and second means for occluding each include an expandable structure.

3. The system according to claim 2, wherein the expandable structure includes an expandable scaffold and an inflatable balloon.

4. The system according to claim 3, comprising a fourth means for controlling the fluid flow to and from the extracorporeal device.

5. The system according to claim 4, comprising one or more fluid pressure sensors coupled near first ends of the first and second catheters, the first and second catheters being coupled to the extracorporeal device at the first ends.

6. The system according to claim 5, wherein the third means for processing includes a fifth means for oxygenating the fluid.

7. The system according to claim 6, wherein the third means for processing includes a sixth means for cooling and heating.

8. The system according to claim 7, wherein the third means for processing includes a seventh means for delivering and removing one or more compounds to the fluid.

9. The system according to claim 1, wherein the one or more organs include the brain and the heart.

10. A method for the selective treatment of one or more organs, said method comprising: compartmentalising said one or more organs by occluding a first lumen downstream of said one or more organs with a first catheter, and by occluding a second lumen upstream of said one or more organs a second catheter; extracting fluid from the compartment; processing the fluid; and delivering the processed fluid to the compartment.

11. The method according to claim 10, wherein the first lumen is occluded by the first catheter including a first occluding means, and the second lumen is occluded by means of the second catheter including a second occluding means.

12. The method according to claim 11, wherein extracting, processing, and delivering are carried out by an extracorporeal device.

13. The method according to claim 12, wherein the processing the fluid includes oxygenating the fluid.

14. The method according to claim 13, wherein the processing the fluid includes cooling or heating the fluid.

15. The method according to claim 14, wherein the processing the fluid includes delivering or removing one or more compounds to the fluid.

16. The method according to claim 15, comprising measuring a first fluid pressure at or adjacent an extraction site and a second fluid pressure at or adjacent a delivery site.

17. The method according to claim 16, comprising controlling fluid flow rates so the first fluid pressure is substantially the same as the second fluid pressure.

18. A system comprising: first and second catheters having: an expandable structure near a first end of the respective first and second catheters, the first end opposite a second end of the respective first and second catheters; and a first opening at the first end of the respective first and second catheters; and an extracorporeal device coupled to the second end of the respective first and second catheters, the extracorporeal device delivers fluid to the first catheter and the second catheter delivers fluid to the extracorporeal device.

19. The system according to claim 18, wherein the expandable structure is spaced from the first opening of the respective first and second catheters.

20. The system according to claim 18, wherein the expandable structure has an outer surface flush with the first opening of the respective first and second catheters.

Description

ACCOMPANYING FIGURES

[0025] The invention will be further described with reference to the drawings and figures, in which

[0026] FIG. 1 is a schematic representation of natural blood circulation in a human patient;

[0027] FIG. 2 is a schematic representation of a conventional ECMO system;

[0028] FIG. 3 is a schematic representation of a system according to the present invention;

[0029] FIGS. 4A to 4C are a schematic representation of a catheter used in a system according to the present invention;

[0030] FIGS. 5A to 5D are schematic representations of functional components of a system according to the present invention; and

[0031] FIGS. 6A to 6C are schematic representations of a puncture device used in a system according to the present invention.

[0032] FIG. 7 is a schematic representation of one or more functional components adjacent the distal end of the catheter.

[0033] The embodiments described herein are provided as exemplary and non-limiting embodiments of the present invention.

DETAILED DESCRIPTION

[0034] For reference purposes, FIG. 1 illustrates the native blood circulation in a patient. The heart pumps blood through the circulatory system. Oxygen-depleted blood leaves the organs is pumped by and through the heart, and is oxygenated by the lungs. Oxygenated blood is recirculated to throughout the patient's circulatory system and redistributed to the organ.

[0035] In the event of cardiac arrest, blood oxygenation is halted, and a device, such as an ECMO device, may be used as an artificial heart-lung machine. FIG. 2 illustrates a conventional ECMO treatment, in which blood is extracted via the femoral vein (usually by gravitational force), oxygenated and infused back into the patient via the femoral artery. Cardiac arrest patients are susceptible to have an increased risk of vital organ congestion and edemas which may impair or completely stop blood flow to the organs. Increased pressure may be required to deliver blood past the existing congestion and edemas and improved drainage may be needed to reduce congestion/edemas. With a typical ECMO flow rate of between 4 to 6 litres per minute at the device, this pressure decreases by the time blood has reached the patient's brain and heart.

[0036] The oxygenated blood is distributed throughout the patient's whole circulatory system, so that the actual amount of oxygenated blood delivered to and drained from the brain and the heart is further compromised.

[0037] The access points will in part be dictated by accessibility to the circulatory system. It may be that the patient has sustained injuries or received treatment in the desired access area which makes insertion difficult. In practice, the ECMO flow is delivered in a retrograde manner, i.e. against the native blood flow, due to accessibility constraints.

[0038] With reference to FIG. 3, there is illustrated a system 1 for the selective treatment of one or more organs, said system 1 comprising a first catheter 2 comprising a means 3 for occluding a first lumen downstream of said organ(s); a second catheter 4 comprise a means 5 for occluding a second lumen upstream of said organ(s); an extracorporeal device 6 configured to deliver fluid through the first catheter 2 and to receive fluid through the second catheter 4, and comprising means 7 for processing the fluid.

[0039] In this embodiment, the access point of the first catheter 2 is the femoral artery, for example adjacent the patient's groin area. The access point of the second catheter 4 may be the femoral vein, for example also adjacent the patient's groin area. Other access points include, but are not limited to transfemoral, transaxillary/subclavian, transaortic, transapical, transcaval, transiliac and transcarotid access points. The access point of the first catheter 2 and the access point of the second catheter 4 may be adjacent, or may be remote. For example, the access point of the first catheter 2 may be in an artery, such as the femoral artery, and the access point of the second catheter 4 may be in a vein, such as the jugular vein (i.e. closer to the brain). In some embodiments, the first catheter 2 may be in arterial femoral artery or the subclavian artery. In some embodiments, the second catheter 4 may be in the jugular vein.

[0040] With reference to FIGS. 4A to 4C, the proximal side (closer the access point of the catheter) is designated by P, and the distal side (further from the access point of the catheter) is designated by D. The first and second catheter 2, 3 may be configured in the same manner, or may have different structures. The catheters 2,4 will be described using a first catheter 2 as an example. The features described with reference to the first catheter 2 are applicable to the second catheter 4, unless otherwise specified.

[0041] The first catheter 2 may be inserted through an access point (not shown) and advanced through a lumen 8 (e.g. femoral artery) of the patient by means of a delivery sheath 9.

[0042] The catheter 2 comprises a channel 10 for fluid communication with an extracorporeal device 6. In this embodiment, the first catheter 2 comprises a channel 10 for delivering processed (e.g. oxygenated) blood into the patient's, and the second catheter 4 comprises a channel for draining (e.g. oxygen-depleted) blood from the patient for subsequent delivery to the extracorporeal device 6.

[0043] The catheter 2 comprises means 3 for occluding a lumen. Preferably, the occlusion means comprises an expandable structure 11.

[0044] The expandable structure 11 may be coupled to or adjacent the distal end of the catheter 2, so as not to hinder the distal opening of the catheter 2. Preferably, distal end of the catheter 2 does not substantially extend beyond the expandable structure 11, and in some embodiment, the distal opening of the catheter 2 is flush with the outer surface of the expanded occlusion means 3.

[0045] The expandable structure 11 may be folded in a delivery configuration (see FIG. 4A) so as to fit within the delivery sheath 9, and may be expanded into an occluding configuration (see FIG. 4B and 4C). In the occluding configuration, the occluding means 3 may occlude the interstitial space between the outer surface of the catheter 2 and the inner surface of the lumen 8. The expandable structure 11 may comprise an expandable scaffold and/or an inflatable balloon, which may be controlled extracorporeally by the medical practitioner.

[0046] In the occluding configuration, oxygenated blood may circulate from the extracorporeal device 6 through the channel 10 of the catheter and be delivered exclusively to the target compartment (i.e. between the occlusion means of the first catheter 2 and the occlusion means of the second catheter 4).

[0047] The catheter 2 may comprise a one or more fluid pressure sensors 12. The one of more fluid pressure sensors 12 may be located at or beyond the distal end of the catheter 2. The sensor(s) 12 may be coupled to the catheter 2, or may be separately provided through the channel 10. The pressure sensor(s) preferably measures the pressure of the fluid being delivered (or drained) at the delivery (or drainage) point, i.e. adjacent the distal end of the catheter 2 (or catheter 4). The detected pressures may be monitored in order to adjust the delivery and/or drainage pressure.

[0048] With reference to FIGS. 5A to 5D, the catheter 2 may comprise one or more additional functional components, preferably at or adjacent the distal end of the catheter 2.

[0049] FIG. 5A illustrates a catheter 2 with an occlusion balloon 11. The distal end of the catheter extends from the occlusion balloon 11. FIG. 5B illustrate a catheter 2 comprising a dilator 12, with a guide wire 13 slidably extending therethrough.

[0050] FIGS. 5C and 5D illustrate a diffusor 14 located at the distal end of the catheter 2. The diffusor 14 may comprise a plurality of apertures to allow the fluid to flow freely therethrough and preferably to direct the flow of fluid. This is advantageous in that it mitigates the effects of retrograde infusion of fluid against the native blood flow.

[0051] A puncture component 15 is coupled to the distal end of the diffusor 14, but may alternatively be couple to the distal end of the catheter 2. The puncture component 15 comprises a flexible tip 16. In FIG. 5D, the flexible tip 16 is in a working/puncture configuration, and may be maintained in said puncture configuration by means of a cover 17. The cover 17 may be conical or tapered, so as to serve as a dilator. In FIG. 5C, the flexible tip 16 is in a non-functional configuration. For example, the flexible tip 16 is curled upon itself so as to shield the sharp puncturing end thereof. In this configuration, the flexible tip 16 may be advanced atraumatically through the lumen, without the risk of accidental puncture. The puncture component 15 may be conical or tapered to facilitate puncture and insertion through the lumen wall. The puncture component 15 may be arranged and configured to allow fluid flow therethrough. For example, the puncture component 15 may comprise or consist of a mesh.

[0052] An alternative puncture component 17 is illustrated in FIG. 6A to 6C. In this embodiment, the catheter 2 comprises an occlusion means 11, preferably a dilator, and a puncture component 17 with a puncture tip 18. The puncture component 17 slidably extends through the dilator 12. The dilator 12 comprises a distal opening. The inner dimensions of the distal opening of the dilator 12 may be such that the puncture tip 18 is prevented from sliding back into the dilator 12 or the catheter 2. FIG. 6A illustrates the puncture component 17 in a puncture configuration. In FIG. 6B, the lumen wall has been punctured and the dilator 12 dilates the puncture for access. In FIG. 6C, the flexible distal portion of the puncture component 17 curls upon itself to shield the puncture tip 18.

[0053] The flexible tip 16 and the puncture component 17 may comprise or consist of a shape-memory material, such as nitinol, so that the flexible tip 16 and the puncture component 17 have a set atraumatic (for example curled) configuration, and a stretched configuration for puncture.

[0054] With reference to FIG. 7, the one or more functional components may be located at any location adjacent the distal end of the catheter, provided they are located distally from the occlusion means 11. The catheters 2,4 may comprise one or more diffusors 14 and/or one or more occlusion means 11. The functional components can preferably be controlled and manipulated separately by the medical practitioner, who is then able to selectively and individually treat different parts of the patient's anatomy. For example, the patient may have been injured and suffer from haemorrhage. In this situation, it is possible to compartmentalise the patient's circulatory system (by strategically positioning occlusion means) so as to distribute less or no blood and/or blood thinners to the injured area.

[0055] The present invention also enables the administration of a first treatment of a first target area and a second treatment of a second target area, for example by segmenting the catheter 2 using multiple occlusion means 11. The channel 10 may comprise a multi-lumen structure to support the different treatments.

[0056] The system may comprise means 13 for controlling the fluid flow to and/or from the extracorporeal device 6. Pressure control may be effected by means of an integrated flow optimisation algorithm. The extracorporeal device 6 may comprise a pump, such as a centrifugal pump (not shown).

[0057] The extracorporeal device 6 comprises means 7 for processing a fluid. In a preferred embodiment, the processing means 7 comprise means for oxygenating the fluid, an oxygenator, such as a membrane oxygenator. Oxygen-depleted blood is drained from the patient, in particular from the target compartment, via the second catheter 4, oxygenated through the extracorporeal device 6, and oxygenated blood is delivered to the compartment via the first catheter 2.

[0058] The processing means 7 may alternatively or additionally comprise means for cooling and/or heating. This feature may be beneficial in the case of hypothermic treatment. The temperature of the fluid may be lowered in order to lower the body temperature. This prevent or reduces brain damage during cardiac arrest. Alternatively, the fluid may be heated in the context of a thermal treatment sometimes used in cancer patient. A tumour may be compartmentalised using the present system, and selectively heated to kill cancerous cells.

[0059] The processing means 7 may alternatively or additionally comprise means for delivering one or more compounds to the fluid. It may for example be beneficial to administer one or more of a blood thinning compound, a thrombolytic compound, an anti-inflammatory compound, an anti-swelling compound, and the like. In the case of a cancer treatment, it may be beneficial to administer one or more cytotoxic drugs, with or without heating the fluid.

[0060] The processing means 7 may alternatively or additionally comprise means for removing one or more compounds from the fluid. For example, the processing means 7 may remove carbon dioxide, toxins and/or drugs from the fluid.

[0061] In an aspect of the invention, there is provided a method for the selective treatment of one or more organs, said method comprising the step of compartmentalising said one or more organs by occluding a first lumen downstream of said organ(s) by means of a first catheter, and by occluding a second lumen upstream of said organ(s) by means of a second catheter; and the steps of extracting fluid from the compartment, processing the fluid and delivering the processed fluid to the compartment.

[0062] The present method enables the compartmentalisation and selective treatment and/or perfusion of critical organs, by occluding upstream and upstream of the target organs. Blood circulates through the extracorporeal device 6, for example for oxygenation and carbon dioxide removal. The oxygenated blood flows through the first catheter 2, by-passing non-critical organs, and is delivered to the target compartment to be treated. Oxygen is delivered to the critical organs (such as the brain, the heart and lungs), and oxygen-depleted blood is drained through the second catheter 4. Therefore, the bulk of the oxygen reaches the critical organs, which are prioritised over non-critical organs. There is negligible loss of pressure as the oxygenated blood is delivered directly to the compartment.

[0063] In the event of cardiac arrest, the first responder will typically apply Cardio-Pulmonary Resuscitation (CPR), in order to maintain partial blood flow to the brain and preserve brain function. CPR relieves the heart from its pumping function, and oxygen is mechanically circulated to the patient's blood for oxygenation, until the patient is connected to the present system.

[0064] The medical responder incises the patient's skin in the groin area (or other area close to a suitable lumen) to access the femoral artery. A delivery sheath 8 is inserted through the access point into the artery. The system 1 may comprise one or more functional components in order to facilitate the puncture of the lumen wall (e.g. a puncture needle, a flexible tip 16 or a puncture component 17) and to facilitate the insertion of the system 1 into the lumen (e.g. a dilator 12).

[0065] Should the sheath 8 be improperly inserted, the step is repeated, atraumatically owing to the small catheter diameter (preferably from 3 to 5 mm diameter). The sheath 8 is advanced through the patient's circulatory system until its distal end is adjacent the intended occlusion site downstream of the critical organ(s). The first catheter 2 is inserted into and advanced through the sheath 8, with the expandable structure 11 in a folded, delivery configuration. The first catheter 2 is inserted so as to infuse the lumen in a retrograde manner against the native flow. The first catheter 2 is advanced beyond the distal opening of the sheath 8, and the expandable structure 8 is deployed into an occluding/working configuration. In the deployed configuration, the occluding means 3 prevents fluid circulation into the compartment, except through the channel 10 of the first catheter 2.

[0066] A delivery sheath 8 is inserted through a second access point to the femoral vein (or any other suitable lumen). The second catheter 4 is inserted so as to drain the lumen counter-current to the native flow. The sheath 8 is advanced through the patient's circulatory system until its distal end is adjacent the intended occlusion site upstream of the critical organ(s). The second catheter 4 is inserted into and advanced through the sheath 8, with the expandable structure 11 in a folded, delivery configuration. The second catheter 4 is advanced beyond the distal opening of the sheath 8, and the expandable structure 8 is deployed into an occluding/working configuration. In the deployed configuration, the occluding means 3 prevents fluid circulation from the compartment, except through the channel 10 of the second catheter 4.

[0067] Blood in the circulatory system outside the compartment is stagnant, and the system 1 does not deliver fluid to the organs and tissues outside compartment. Thus, the present system is most beneficial is emergency and critical situations.

[0068] In the example of FIG. 3, the most critical organs are the brain and the heart, but the compartment may also include the lungs. Therefore, a fluid circulation circuit is formed comprising the extracorporeal device 1, the first catheter 2, the heart, the lungs, the brain and the second catheter 4.

[0069] The first catheter 2 may occlude the aorta, adjacent but beyond the bifurcation to the cerebral vessels.

[0070] The second catheter 4 may occlude the inferior vena cava, preferably adjacent the heart.

[0071] It is envisaged that the present method may be used for the treatment of other organs and/or tissues, with suitable upstream and downstream occlusion sites. Other organs and/or tissues may be treated, provided a suitable compartment can be isolated by occluding lumens at strategic sites. The choice of the occlusion sites may depend on the accessibility of the area to be treated. Certain parts of the patient may be inaccessible, if the patient is trapped after an accident or has been injured. It may also be that relevant access areas are not accessible due to prior treatments or procedures on the patient.

[0072] The first catheter 2 and the second catheter 4 are in fluid communication with the extracorporeal device 6. The first catheter 1 may be fluidly coupled to a fluid outlet of the extracorporeal device 6 and the second catheter 4 may be fluidly coupled to an inlet for receiving fluid from the second catheter 4.

[0073] The extracorporeal device 6 drains blood from the compartment via the second catheter 4, for example by means of a pump, such as a centrifugal pump. A key aspect of the present invention is that the system 1 drains blood from the compartment, thereby effectively drawing fluids from the crucial organs. When the patient is in cardiac arrest, the blood vessels have a tendency to dilate so that the tissues become congested with blood and drainage is impaired. The active and selective drainage achieved by the present system creates a fluid pressure differential in the critical organs, which forces the take-up of oxygenated blood by the fluid-drained critical organs by enhanced perfusion pressure. The enhanced drainage also allows the removal of toxins and other undesirable compounds from the congested organs.

[0074] The oxygen-depleted blood drained from compartment is processed by the extracorporeal device 6. The process step may include any one or more steps selected from adding one or more compounds (e.g. oxygen and/or one or more drugs) to the fluid, removing one or more compounds (e.g. carbon dioxide and/or toxins), heating and/or cooling the fluid.

[0075] The fluid pressure may be monitored at one or more locations. Preferably, the fluid pressure is measured as the fluid exits the first catheter 2 and/or as the fluid enters the second catheter 4. The pressure may be measured by means of one or more sensors coupled to the catheter(s) or used in conjunction with the catheter(s). The pressure readings may be entered in a control processor to adjust the incoming and outgoing fluid pressure.

[0076] The fluid flow is controlled and adjusted based on parameters such as the processing (e.g. oxygenation) rate of the extracorporeal device 6, the blood pressure of the patient, the pressure differential between the fluid delivery pressure and the fluid extraction pressure. In conventional ECMO devices, a balance must be struck between the required physiological blood flow and the capacity of the device to process large volumes of fluid. Since the present method requires a smaller volume of fluid to be circulated, it is possible to achieve an efficient fluid processing, whilst maintaining adequate pressures.

[0077] The catheters 2,4 may be configured and arranged to partially or completely occlude the lumen 8, so that the inflow and/or outflow of oxygenated blood may be adjusted. The degree of occlusion (e.g., the degree of expansion of the expandable structure) may be adjusted to fit the intended purpose Alternatively or additionally, the occlusion means may be intermittently opened/closed. For example, it may be required to create a restricted, fully closed compartment around the critical organ(s), or to allow some oxygenated blood to be delivered to other organs. The diverted portion of the oxygenated blood may be homogeneously delivered to the rest of the patient's body, or may be directed to specific organs (other than the primary critical organs). The latter may for example be achieved by dividing the patient's circulatory system into several compartments by strategically positioning a plurality of catheters. The degree of irrigation of each such compartment may be individually adjusted.

[0078] In the simplest embodiment, two catheters 2,4 are positioned to create a first compartment around one or more critical organs (e.g., the brain and/or heart). Processed fluid (e.g., oxygenated blood) is circulated throughout this first compartment using a first processing means. The rest of the circulatory system outside the first compartment, i.e., the second compartment, may be treated separately, by circulating fluid processed by a second processing means, set under the same or different conditions as the first processing means.

[0079] This compartmentalisation may also be beneficial where the patient is bleeding. The present system may be used to prevent or minimise blood loss, by positioning the catheters to isolate the breach area.

[0080] Although the present invention has been described within the context of the critical oxygenation of the brain and heart, it is envisaged that it could have other advantageous implementations involving the selective treatment of organs and/or tissues within a compartment. For example, treatments such as drug delivery are described herein which may find a beneficial application in other medical treatments such as localised chemotherapy, hypothermic and thermal treatments.

[0081] Thus, the present invention provides a system and a method for the selective treatment of a patient's organs and/or tissues. The present invention allows an effective treatment of the target organs, by providing an improved and enhanced drainage of the target organs, which during cardiac arrest are congested with fluids and cannot be effectively infused.

[0082] The invention provides mitigates the problems encountered by conventional life support apparatus, and in particular by conventional ECMO devices. Critical organs can be prioritised so as to prevent or reduce the risk of brain damage, and ultimately so as to increase the survival rate of cardiac arrest patients.