Mechanical circulatory assistance device

Abstract

One aspect of the invention relates to a mechanical circulatory assistance device (100) comprising: a rod (11) for insertion into a blood vessel; a plurality of fins (12) attached to the rod (11), the plurality of fins comprising an electroactive material; a control module (14) connected to the plurality of fins (12), the control module (14) being configured to: obtain information relating to a systole of a cardiac cycle; and upon obtaining the information, command an actuation of the plurality of fins (12) so as to induce a displacement of the plurality of fins (12), the displacement being a folding of the plurality of fins (12) towards the rod (11) in a direction corresponding to a direction of blood flow in the blood vessel. Figure to be published with the abstract: Figure 1

Description

Title of the invention: Mechanical circulatory assistance device TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of circulatory assistance for people with heart failure.

[0002] In particular, the invention relates to a mechanical circulatory assistance device. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] Heart failure is the inability of the heart to provide adequate cardiac output to meet the body's metabolic needs. It can affect the left ventricle, the right ventricle, or both ventricles. It is a major public health problem with high morbidity and mortality despite a wide variety of treatments. In fact, heart failure is the leading cause of death worldwide.

[0004] The most serious pathology associated with heart failure is cardiogenic shock, defined as the inability of the ventricular pump to generate sufficient blood flow to allow peripheral organs to meet their metabolic needs, and which has a particularly high mortality rate (40 to 70%). Cardiogenic shock is a frequent reason for admission to intensive care and requires the rapid implementation of often aggressive therapies.

[0005] Cardiac-stimulating drugs such as dobutamine help maintain cardiac output to supply peripheral organs but are not always sufficient. When signs of cardiogenic shock persist despite medication, implantation of a temporary mechanical circulatory support device is necessary.

[0006] Temporary mechanical circulatory support devices prevent complications by restoring blood flow to other organs instead of the heart. These devices are installed temporarily, for example, while the patient recovers their native cardiac function. If such recovery of native cardiac function does not occur, the patient must then be referred for a heart transplant or implantation of a long-term mechanical circulatory support device.

[0007] There are currently three main types of temporary mechanical circulatory support devices: the intra-aortic balloon pump, the Abiomed Impella® heart pump, and veno-arterial extracorporeal membrane oxygenation (ECMO) systems. These devices have demonstrated only partial efficacy in certain situations and are associated with numerous adverse effects and / or complications.

[0008] The intra-aortic balloon counterpulsation device consists of inflating a balloon with gas during diastole and deflating it during systole. Its purpose is to unload the left side of the heart, as the balloon's deflation causes a drop in aortic pressure and aspiration of the ejected blood. However, this device has shown only limited efficacy in physiological studies, particularly with regard to generating flow in patients with low cardiac output (an increase of only 15 to 20% compared to the initial flow). Furthermore, its use is associated with numerous complications, notably vascular (risk of acute limb ischemia, vascular rupture, and hemorrhage), and incorrect balloon placement can cause mesenteric or even renal ischemia.Its use is now being questioned, and it has been removed from European cardiology guidelines following the publication of a clinical trial conducted in 2012 which concluded that there was no significant improvement in prognosis in patients treated with intra-aortic balloon counterpulsation compared to patients treated in a standard manner without intra-aortic balloon counterpulsation.

[0009] The Impella® cardiac pump is a micro-axial pump introduced via a vascular route. Three versions exist: a lightweight, percutaneous version; a heavier, surgically introduced version; and a version for the right heart chambers, which is rarely used and not available in France. Its positioning is difficult and often requires manipulation and setup in a catheterization lab for X-ray imaging, thus preventing its use at the patient's bedside. It therefore requires technical expertise from the practitioner and specific logistical arrangements, meaning it cannot be used for the immediate stabilization of all patients. It also presents a significant risk of hemolysis, due to the need for blood to enter a miniaturized suction tract in the left ventricle, then pass through a miniature pump rotating at high speed before being re-ejected into the aorta.Contact with red blood cells is therefore high, and the risk of lysis (with its consequences of severe acute kidney injury) is frequent. Furthermore, the actual flow rate is lower than the estimated flow rate, and its effectiveness is often limited in the percutaneous version. The more cumbersome version is more effective, but it requires surgical access and therefore presents a greater risk of complications. In addition, stopping the pump is not possible except for its immediate removal because the risk of thrombosis is very high. It is therefore not possible to perform breaks to assess the patient's weaning from the assistive device.

[0010] Venous-arterial ECMO is the preferred support for cardiogenic shock situations, given the generation of a very high flow rate, up to 4 or 5 liters, which relieves pressure in the right heart chambers and returns blood to the aorta via a retrograde route. It is a biventricular support system consisting of a cannula An arterial cannula and a venous cannula are connected to a circuit comprising an electric centrifugal pump and a membrane oxygenator. It can be implanted at the patient's bedside in an immediate emergency, even during cardiac arrest. However, due to the large size of the two cannulas, infections and vascular complications such as leg ischemia and hemorrhages are frequently observed. Other complications can occur, including biological complications (thrombocytopenia, hemolysis, etc.). Mechanical problems related to the pump and oxygenator (e.g., pump failure) are also relatively common.Furthermore, the electric centrifugal pump generates a continuous flow, which therefore does not respect the physiological flow rate, and this flow is reinjected most of the time via the retrograde femoral arterial route, and therefore does not unload the left heart, thus promoting the development of pulmonary edema (a significant mortality factor in patients on veno-arterial ECMO) and the need to sedate the patient and provide artificial ventilation.

[0011] There is therefore a need for temporary mechanical circulatory assistance devices which do not present or which limit the aforementioned disadvantages. Summary of the invention

[0012] The invention offers a solution to the problems mentioned above, by proposing a mechanical circulatory assistance device integrating a system of fins placed in a blood vessel and configured to move in the direction of blood flow during systole, so as to promote the expulsion of blood from the heart to the various organs.

[0013] One aspect of the invention thus relates to a mechanical circulatory assistance device comprising:

[0014] - a rod intended to be inserted into a blood vessel;

[0015] - a plurality of fins fixed to the stem;

[0016] - a control module connected to the plurality of fins, the control module being configured for:

[0017] obtain information relating to a systole of a cardiac cycle; and

[0018] upon obtaining the information, command an actuation of the plurality of fins so as to induce a displacement of the plurality of fins, the displacement being a folding of the plurality of fins towards the rod in a direction corresponding to a direction of blood flow in the blood vessel.

[0019] The “stem” is a stem made of a semi-rigid material, similar to the stems used in conventional catheters. This stem is intended to be implanted in vessels such as the pulmonary artery or the aorta, depending on the type of assistance required. It is noted that the stem can also “extend” into a cardiac chamber, as detailed below.

[0020] By "fin," we mean an element fixed to the rod, projecting from an external surface thereof. In other words, the fins extend outwards from a lateral surface of the rod (i.e., towards the internal surface of the vessel into which the rod is inserted, when the device is in place).

[0021] By "information relating to a systole," we mean any information connected with a systole of a cardiac cycle. In particular, the information may indicate the onset of systole. It is noted that, in this case, the information is not necessarily perfectly synchronized with the onset of systole, but may incorporate an advance or a delay of a few milliseconds relative to the start of systole.

[0022] By "obtaining information", it is understood that the information may be received or determined, depending on the embodiments.

[0023] As soon as the information is obtained, the control module is configured to trigger a movement of the vanes. This movement causes the displacement of a volume of blood and the generation of a blood flow. By synchronizing with cardiac activity, the flow thus generated respects cardiovascular physiology, which improves the overall effectiveness of circulatory support and avoids adverse effects for the patient.

[0024] It is noted that the circulatory support device according to the invention is very little affected by the risk of thrombosis, unlike Impella® or ECMO, because it does not involve any blood passing through a pump. The flow generated by the fins is physiological (it is synchronized with the flow generated by the patient's native heart) and it is anterograde (i.e., in the "natural" direction of blood circulation), which greatly reduces the risk of pulmonary edema. Furthermore, the insertion of this device in the patient is similar to that of a catheter, and therefore does not require any specific surgical procedure, unlike Impella® or ECMO. Finally, it is noted that once in place, if the catheter malfunctions (electrical problem, mishandling, etc.), blood flow can continue to circulate around the fins and prevent serious damage.

[0025] The circulatory assistance device according to the invention is typically intended to be implanted in the systemic circulation or in the right circulation.

[0026] By "folding," it is understood that the free end of the fins (i.e., the end opposite the end connected to the rod) folds back towards the rod. In other words, the fins undergo an angular displacement in the direction of blood flow.

[0027] In particular, an angular displacement of each fin among the plurality of fins can be between 60° and 130°, for example between 80° and 110°.

[0028] By "angular displacement", it is understood that the angle formed between a fin in the rest position (i.e. before actuation), and between the same fin once actuation (at its maximum distance from its starting position).

[0029] In one or more embodiments, the control module is further configured to:

[0030] - obtain a cardiac signal related to a subject's cardiac activity;

[0031] - determine the information from the received cardiac signal.

[0032] The cardiac signal can be any signal relating to cardiac activity of the subject, for example an electrocardiogram (ECG) signal, a signal obtained by photoplethysmography (signal relating to heart rate), by cardiac echo-Doppler or by blood pressure measurement.

[0033] The signal can be received from an external device, for example, a cardiac activity measurement system, or determined by the control module. In the latter case, the circulatory support device may incorporate a cardiac activity measurement system. In the case of an ECG system, the device may further include electrodes connected to the control module and configured to measure cardiac electrical signals related to the subject's cardiac electrical activity. The control module may also be configured to determine the electrocardiogram signal from the received cardiac electrical signals.

[0034] Alternatively, the information can be determined by an external device (for example, a heart activity measurement system) and sent to the control module.

[0035] In one or more embodiments, the stem and / or the plurality of fins are covered with a layer of electrically insulating biocompatible material.

[0036] For example, the electrically insulating biocompatible material layer is a biocompatible silicone layer.

[0037] In one or more embodiments, the plurality of fins is arranged along a portion of the stem, said portion having a length between 10 cm and 30 cm.

[0038] In one or more embodiments, the plurality of fins is distributed over a plurality of levels, in which the number of fins per level is between 1 and 8.

[0039] In particular, the number of fins per level can be between 2 and 5. For example, the number of fins per level can be equal to 3 or 4. Tests have indeed shown that a number of fins per level equal to 3 or 4 made it possible to obtain the greatest flow.

[0040] Furthermore, for each level of the plurality of levels, the level's fins can be uniformly distributed around the stem. This allows for a good distribution of the flow all around the stem, and to prevent the stem from becoming off-center relative to the lumen of the blood vessel into which it is inserted.

[0041] It is also noted that the number of fins per level can be constant. In other words, for each level, the number of fins can be the same.

[0042] In these embodiments, the fins can be aligned along a longitudinal direction of the rod.

[0043] In other words, each fin of one level is aligned, in the direction of the stem, with a corresponding fin of another level. For example, if the number of fins per level is equal to 3, each level comprises a first fin, a second fin and a third fin, and all the first (resp. second, resp. third) fins are arranged "one below the other", i.e. are aligned in the direction of the stem.

[0044] This allows for a more homogeneous blood flow, thus reducing the risk of clots or endovascular lesions.

[0045] In one or more embodiments, each level is spaced from a neighboring level by a fixed distance of between 0.5 cm and 2 cm.

[0046] By "fixed distance" it is understood that the levels are equally distributed, i.e. that the distance between two neighbouring levels is fixed.

[0047] In one or more embodiments, each fin of the plurality of fins has a length between 6 mm and 12 mm.

[0048] In one or more embodiments, the rod may have a diameter between 1 mm and 10 mm.

[0049] In one or more embodiments, each fin of the plurality of fins comprises a first end connected to the stem and a second end called free opposite to the first end, in which each fin of the plurality of fins has a tapered shape at its free end.

[0050] By "tapered shape", it is understood that the shape of the fin is thinned at the free end.

[0051] Such a shape makes it possible to minimize the stresses on the free end of the fin, and thus to avoid undesirable deformation of the fin due to blood flow (for example, to prevent the fin from "bending").

[0052] In particular, the shape of each fin in the plurality of fins can be flared at its first end (i.e., in the example of [Fig. 7a] to 7f, at the point where it is fixed to the stem, that is, at the opening 17) and narrowed towards its free end. For example, the shape of each fin in the plurality of fins can be substantially triangular (or of a similar geometric shape).

[0053] By "substantially", it is understood that the overall shape of the fin may be triangular, even if the fin is not strictly speaking a triangle (in particular, the free end is preferably rounded and does not include any salient angle).

[0054] The actuation of the fins can be mechanical, hydraulic, electrical and / or magnetic.

[0055] In embodiments, the actuation of the fins is an electrical actuation, the plurality of fins comprises an electroactive material, the control module is connected to an electrical power source and the control of the actuation of the fins comprises: applying, via the electrical power source, a predetermined electrical voltage value to the plurality of fins so as to induce a deformation of the plurality of fins, the displacement of the plurality of fins resulting from said deformation of the plurality of fins.

[0056] By "electroactive material" is meant a material that deforms under the application of an electric field. Such electroactive materials include, in particular, electroactive polymers (EAPs), such as the PVDF-TrFE-CFE terpolymer, for example.

[0057] In these embodiments, the fins comprise an electroactive material that deforms under the action of an electric field. When an electric field is applied, these fins move so as to generate a blood flow in the same direction as the blood circulation, and thus assist cardiac function.

[0058] According to embodiments, the electrical power source can be integrated into a housing that is part of the device (and integrates the control module and the power source) or can be external to the device.

[0059] In embodiments, each fin of the plurality of fins comprises a layer of electroactive material having a first surface and a second surface, wherein the first surface is at least partially covered with a first layer of electrically conductive material, and the second surface is at least partially covered with a second layer of electrically conductive material, the first layer of electrically conductive material and the second layer of electrically conductive material being electrically insulated and each connected to the electrical power source.

[0060] Thus, the first layer of electrically conductive material and the second layer of electrically conductive material act as electrodes and allow the electroactive material to be subjected to an electric field.

[0061] In one or more embodiments, prior to obtaining the information, no electrical voltage value is applied to the plurality of fins, in which the predetermined value is strictly positive.

[0062] In these embodiments, no electrical voltage is applied "basically" to the plurality of fins (i.e. during the rest of the cardiac cycle), and a non-zero electrical voltage is applied to the plurality of fins when obtaining information relating to systole.

[0063] Alternatively, the control module is further configured to control the electrical power source to control an application, prior to obtaining information, of a reference electrical voltage value to the plurality of fins, the reference electrical voltage value being strictly greater than the predetermined value.

[0064] In these embodiments, a reference electrical voltage Tref is applied "as a basis" to the plurality of fins, and an electrical voltage Ti strictly less than Tref (Ti may be zero or not) is applied to the plurality of fins when obtaining the information relating to systole.

[0065] Indeed, depending on how the fins are positioned on the rod, the expected effect can occur by applying a non-zero electrical voltage value, or, on the contrary, by lowering the electrical voltage value (for example by cutting off the electrical voltage).

[0066] Another aspect of the invention relates to a computer-implemented method for controlling a mechanical circulatory assistance device comprising a rod for insertion into a blood vessel and a plurality of fins attached to the rod, the plurality of fins comprising an electroactive material, the method comprising:

[0067] - to obtain information relating to a systole of a cardiac cycle; and

[0068] - upon obtaining the information, command an actuation of the plurality of fins so as to induce a displacement of the plurality of fins, the displacement being a folding of the plurality of fins towards the stem in a direction corresponding to a direction of blood flow in the blood vessel.

[0069] The present invention also relates to a computer program comprising instructions for implementing certain steps of the above process, when this program is executed by a processor.

[0070] This program may use any programming language (for example, an object-oriented language or other), and may be in the form of interpretable source code, partially compiled code or fully compiled code.

[0071] Another aspect of the invention relates to a method for manufacturing a mechanical circulatory assistance device defined above, comprising:

[0072] - to obtain a rod intended to be inserted into a blood vessel;

[0073] - obtaining a plurality of fins, the plurality of fins comprising a material electroactive;

[0074] - fix the plurality of fins to the stem;

[0075] - connect the plurality of fins to a control module.

[0076] In one or more embodiments, the plurality of fins comprises a set of fin units, each fin unit comprising at least one fin and one orifice, wherein the attachment of the plurality of fins to the rod comprises, for each fin unit:

[0077] - insert the rod into the opening of the fin unit;

[0078] - fix the fin unit to the rod using a locking system.

[0079] The invention and its various applications will be better understood upon reading the following description and examining the accompanying figures. Unless otherwise specified, the same element appearing in different figures has a unique reference numeral. BRIEF DESCRIPTION OF THE FIGURES

[0080] Other features and advantages of the invention will become apparent from the description, which can be read in conjunction with the figures. These figures are provided for illustrative purposes only and are not intended to limit the scope of the invention.

[0081] Fig. 1 represents a mechanical circulatory assistance device according to one embodiment of the invention.

[0082] Figure 2 represents a mechanical circulatory assistance device according to an embodiment of the invention inserted via the femoral artery into the aorta.

[0083] Figure 3 represents the movement of the vanes of the mechanical circulatory assistance device during the cardiac cycle according to one embodiment of the invention.

[0084] Fig. 4 represents the opening angle of the fins of the mechanical circulatory assistance device during the cardiac cycle according to one embodiment of the invention.

[0085] Fig. 5 represents a cross-sectional view of a mechanical circulatory assistance device according to an embodiment of the invention.

[0086] Figure 6 represents a flowchart of a manufacturing process for a mechanical circulatory assistance device according to an embodiment of the invention.

[0087] Figures 7a to 7f represent several examples of fins that can be used within the framework of the present invention.

[0088] Figure 8 represents an example of a control module for the mechanical circulatory assistance device, according to one embodiment of the invention.

[0089] Fig. 9 represents an example of an arrangement of fins located on two successive planes (sectional view along a plane orthogonal to the axis of the rod).

[0090] Fig. 10 represents a temporal activation of the cascading fins, according to one embodiment of the invention.

[0091] Fig. 11 represents an example of actuation of the fins by circulation of a fluid inside the rod. DETAILED DESCRIPTION

[0092] Fig. 1 represents a mechanical circulatory assistance device according to one embodiment of the invention.

[0093] The mechanical circulatory assistance device 100 (hereafter simply referred to as "device") according to the invention comprises a rod 11, on which is mounted a plurality of fins 12 (or "petals").

[0094] The stem 11 can be a "solid" stem or a "hollow" stem. By "solid" stem, it is understood that the stem may include certain elements, for example, electrical cables, but is not intended to receive fluid or medical devices (such as a probe). This means, in particular, that a "solid" stem is not intended to be used as a conventional catheter. Alternatively, the stem can be "hollow," to receive fluid or a medical device such as a probe. In this alternative, the device 100 can also function as a catheter and be used to administer a product (for example, an intravenous drug, a contrast agent, a solution) to the patient, to pass a probe or other medical device, or to remove excess fluid abnormally present in a cavity (drainage).In particular, the 100 device can be used as a Swan-Ganz catheter to measure pressures and flows in the right heart chambers and pulmonary artery ("right-handed" catheterization). In this case, the device can be inserted (similarly to a Swan-Ganz catheter) via a large-bore vein—such as the internal jugular vein, femoral vein, or subclavian vein—and advanced into the right atrium and then the right ventricle, finally coming to rest in the pulmonary artery.

[0095] Similar to a catheter, the stem 11 is intended to be inserted into a vessel (e.g., a large vein or artery). Therefore, the stem 11 is made of a material flexible enough to be inserted into the vessel without causing injury. It should be noted that the stem 11 must nevertheless be rigid enough to be easily inserted and remain in place once positioned. Thus, the stem 11 is made of a material typically used for standard catheters. For example, the stem 11 may be made of a polymer or plastic material. In particular, the material of the stem 11 may be a biocompatible material, such as natural rubber, silicone, polyurethane, polytetrafluoroethylene, polyethylene, polypropylene, polyvinyl chloride, polymethyl methacrylate, polyethylene terephthalate, nylon, ABS, or polycarbonate.When the stem is not made of a biocompatible material (e.g., a latex stem), the entire... The rod 11 and fins 12 can be covered with one or more layers of biocompatible material to ensure that the device 100 is well tolerated by the body. Furthermore, this layer (or these layers) of biocompatible material can be electrically insulating to limit the voltage applied to the fins 12 (and possibly the rod 11).

[0096] The fins 12 are elements projecting along a portion P of the stem 11. For example, the fins 12 can be arranged in "levels" (or "steps"), with one or more fins 12 per level. The number of fins 12 per level can be, for example, between 1 and 8, preferably between 2 and 5, and even more preferably between 3 and 4. If the number of fins is too large, blood flow may be disrupted, leading to a risk of clots.

[0097] Furthermore, the fins can advantageously be evenly distributed by level (i.e., evenly distributed around the stem, meaning that the angle between adjacent fins at the same level is constant). This allows for a good balance in the distribution of blood flow all around the stem and prevents the stem from becoming off-center relative to the blood vessel into which it is inserted (conversely, if all the fins are on one side of the stem, there is a risk that the stem will adhere to the opposite wall of the blood vessel).

[0098] The levels can be equidistant from each other, for example, spaced at a fixed distance of between 0.5 cm and 2 cm, preferably between 0.8 cm and 1.5 cm. Depending on the insertion method and the final positioning of the device 100, the portion P of the rod 11 can have a length of between 10 and 30 cm. The number of levels can thus be, for example, between 5 and 50, preferably between 10 and 30. In the example of [Fig. 1], the fins 12 are arranged on 8 equidistant levels, and each level comprises 2 fins arranged opposite each other. Furthermore, the fins 12 of the different levels are arranged one below the other (longitudinal alignment).

[0099] Of course, other arrangements are possible for the fins. For example, the fins 12 of two distinct levels may not be aligned longitudinally, as in the example shown in Figure 9. In this figure, the fins 12 of two successive levels are shown (the fins 12 in solid lines correspond to a first level L1, and the fins 12 in dashed lines correspond to a second level L2). In this example, the fins of level L2 have undergone a rotation of angle θ with respect to the fins of level L1, θ corresponding to half the angle between two adjacent fins of the same level.

[0100] It is noted, however, that an alignment of the fins of the different levels along the stem is preferable, as it allows a more homogeneous blood flow throughout the vessel, which minimizes the risk of clots and endovascular injury.

[0101] Other arrangements are possible, for example the levels may not be equidistant from each other, the number of fins per level may vary from one level to another, etc.

[0102] Referring again to [Fig. 1], to set the vanes 12 in motion, the device 100 further comprises a control module 14. As described below with reference to [Fig. 8], the control module 14 includes, in particular, a processor. The term "processor" in this application refers to a single processor or multiple processors. For example, each processor may be dedicated to one of the tasks necessary for the operation of the device 100, or a single processor may perform several or even all of the tasks necessary for the operation of the device 100. The control module 14 is configured to obtain information relating to a systole of a cardiac cycle of the subject and, upon obtaining this information, to command the actuation of the vanes 12.Activating the fins 12 sets them in motion, and this movement of the fins assists blood circulation and increases the volume of blood circulating to the organs.

[0103] The actuation of the fins 12 can be any type of actuation, such as mechanical, hydraulic, electrical and / or magnetic actuation.

[0104] In some embodiments, one particular embodiment of which is shown in [Fig. 1], the actuation of the fins 12 is electrically actuation, and the control module 14 is connected to an electrical power source 15 via an electrical cable 16a. In the embodiment of [Fig. 1], the electrical power source is part of the device 100, and both the control module 14 and the electrical power source 15 are integrated into a housing 13 (forming part of the device 100) connected to the rod 11 by one or more electrical cables 16b. In other embodiments, the control module 14 may be connected on the one hand to the rod 11 by an electrical cable and on the other hand to an external electrical power source 15. It should be noted that the housing 13 is optional.Such a housing is useful when device 100 is intended to be implanted entirely internally in the patient (for long-term use), but it is optional when device 100 is intended to "exit" the patient (short or medium-term use, in intensive care for example).

[0105] In these embodiments, the fins 12 may be made of a material comprising an electroactive material. An electroactive material is a material whose shape or size changes when stimulated by an electric field. This electric field induces a deformation (in the case of piezoelectric or electrostrictive materials), or a polarization (in the case of ferroelectric materials) of the material. These materials may be polymers, single crystals, or ceramics. In some embodiments, the fins 12 are made of a material comprising an electroactive polymer (EAP). Ferroelectric and / or electrostrictive polymers are examples of electroactive polymers suitable for the fins 12 of the device 100.

[0106] In particular, the fins may be made of (or comprise) an organic ferroelectric relaxer material of the PVDF-TrFE-CFE terpolymer type, also denoted P(VDF-TrFE-CFE) or an organic or hybrid ferroelectric material.

[0107] For example, the fins 12 may comprise one or more layers of electroactive material, covered on both sides, at least partially, by a layer of conductive material acting as an electrode. The two layers of conductive material (on either side of the layer(s) of electroactive material) may be connected by one or more electrical cables to the energy source 15.

[0108] The electroactive material fins 12 of the device 100 are designed to perform a flexing movement during the cardiac contraction phase, in systole. This flexing movement occurs in the direction of blood flow in the vessel into which the device 100 is inserted; that is, the movement of the fins 12 "accompanies" the blood flow in the vessel. At the moment of cardiac contraction (i.e., at the beginning of systole), the fins 12 thus begin to move, thereby facilitating the expulsion of blood into the arteries, towards the various organs.

[0109] The fins can be made of a material offering a compromise between high relative deformation under an electric field and significant blocking force. Indeed, the fins must deform sufficiently to induce movement that assists blood circulation, but must also exhibit sufficient blocking force to withstand the resistance of the medium in which they are intended to be used (the inside of a blood vessel, through which blood flows). It should be noted that the blocking force of a material corresponds to the limiting force that must be applied to the material to prevent its deformation or movement.

[0110] For example, the relative deformation of the fin material under an electric field can be between 0.5% and 1.5%, for example on the order of 1%. The blocking force can be, for example, greater than 8 newtons and preferably greater than 10 newtons. For example, the fin material can have a modulus of elasticity between 0.1 and 200 megapascals, for example 45 megapascals.

[0111] The electrical power source 15 can be, for example, an electric battery that powers the control module 14 via the electrical cable 16a. The electrical cable(s) 16b allow the control module 14 and / or the electrical power source to be connected to the fins 12, in order to allow the control module 14 to command the electrical energy source 15 to apply a predetermined value Ti of electrical voltage to the fins, and thus cause them to move.

[0112] For example, the applied electrical voltage may be an electrical pulse, an electrical voltage ramp or an electrical voltage square of duration between a few milliseconds and a few hundred milliseconds, for example between 5 ms and 200 ms.

[0113] To set the vanes 12 in motion at the beginning of systole, the control module 14 is further configured to obtain information relating to a systole of a cardiac cycle. By "obtain," it is understood that the control module can receive this information or determine it.

[0114] For example, according to one embodiment, the control module 14 can be connected to an external device configured to determine information relating to a systole and send it to the control module 14. In the example of the electrical actuation of the [Fig. 1], the control module 14 is configured to control, upon receiving information from the external device, the electrical power source 15 to apply the predetermined value Tide electrical voltage to the fins 12. The external device can be any device for obtaining a cardiac signal, for example an electrocardiogram (ECG) device, and configured to determine information from the obtained cardiac signal and send it to the circulatory assistance device 100.

[0115] According to another embodiment, the control module 14 can be configured to receive a cardiac signal related to the subject's cardiac activity and to determine, from this cardiac signal, the information derived from the received cardiac signal. For example, the cardiac signal can be received by the control module 14 from an external device configured to determine a cardiac signal. In the example of the electrical actuation of [Fig. 1], it is the control module 14 that determines the information from the cardiac signal, and no longer the external device. The cardiac signal can also be received from a cardiac signal determination system integrated into the device 100, for example, a photoplethysmography system.

[0116] According to another embodiment, the control module 14 can be configured to determine a cardiac signal related to the subject's cardiac activity and to determine information from the determined cardiac signal. For example, the device 100 may include a system for determining a cardiac signal, such as a photoplethysmography system. According to another example, the device 100 may be connected to electrodes placed on the patient and configured to measure signals, and the control module 14 may process the signals measured by the electrodes to construct the ECG signal, and then determine the information.

[0117] The cardiac signal can be, for example, an electrocardiogram (ECG) signal, but also a cardiac signal obtained by other techniques, for example by photoplethysmography (signal related to heart rate), by cardiac echo-Doppler, by blood pressure measurement, etc. In general, the cardiac signal can be any signal related to the patient's cardiac cycle and allowing the determination of the onset of systole.

[0118] The information obtained relates to a systole of a cardiac cycle. Thus, as shown in [Fig. 3], at each systole, the control module 14 commands the actuation of the vanes 12 to set them in motion. In the example of electrical actuation above, the control module 14 can thus command, at each systole, that a predetermined value of electrical voltage be applied to the vanes 12, which then fold back towards the rod 11, in the BC direction of blood flow in the vessel into which the device 100 is inserted.

[0119] In the example of [Fig. 3], the cardiac signal is an ECG signal. Of course, the invention is not limited to such a signal, as mentioned above. It should be recalled that an electrocardiogram (ECG) signal measures the electrical activity of the subject's heart and comprises various characteristic events, represented in [Fig. 3]: • The P wave, which corresponds to the depolarization wave of the atria. It represents the electrical impulse that originates in the sinoatrial node and travels through the atria, causing them to contract. The contraction of the atria allows blood to pass from the atria to the ventricles through the tricuspid and mitral valves. The electrical wave continues its path to the atrioventricular node; • The PR interval or PQ interval, which corresponds to the atrioventricular conduction time, i.e., from the atria to the ventricles. This short pause allows blood to pass through the valves towards the ventricles; • The QRS complex, which corresponds to the depolarization of the ventricles and therefore to the contraction of the ventricles. The electrical impulse travels through the two ventricles via the bundle of His and its branches and causes the ventricles to contract; • The ST segment, which corresponds to the beginning of ventricular repolarization; • The T wave, which is the basis of ventricular repolarization. Ventricular myocytes relax and recharge in order to be able to depolarize again.

[0120] The QRS complex marks the beginning of ventricular systole (denoted Sys in [Fig. 3]). In the embodiment of [Fig. 3], as soon as a QRS complex is detected, the fins are set in motion via the control module 14 (for example by applying a predetermined value of electrical voltage to the fins 12).

[0121] The detection of a QRS complex in an ECG signal is known per se and can, for example, be achieved by thresholding to detect the first deflection after the P wave (which corresponds to an R wave when directed upwards or a Q wave when directed downwards). It is noted that in some embodiments, the electrical voltage can be applied just before the onset of systole (to initiate circulation before ventricular contraction) – in this case, detection can be based on the P wave rather than the QRS complex – or just after the onset of systole (to take over from cardiac contraction) – in this case, detection can be based, for example, on the S wave. Thus, it is understood that, within the scope of the present invention, the actuation of the leaflets is triggered during systole, but is not necessarily strictly synchronized with the onset of systole; it can occur slightly (e.g.(a few ms to a few tens of ms) before or slightly after the start of systole.

[0122] When the fins 12 comprise an electroactive material and the actuation is an electrical actuation as described above, it is noted that the predetermined value may be greater or less than a reference value, which corresponds to an electrical voltage value (possibly zero) applied during the rest of the cardiac cycle.

[0123] For example, according to one embodiment, no electrical voltage is applied outside of the beginning of a systole (i.e. the reference electrical voltage value is zero), and, when determining the information relating to a systole, a non-zero value is applied (which corresponds to the predetermined value Ti of the function applied to the determination of the information relating to a systole).

[0124] Alternatively, the reference voltage is equal to a non-zero value Tref, and, when determining the information relating to a systole, a predetermined voltage Ti is applied, with Ti < Tref. For example, the reference value Tref can be between 10 and 2000 volts and the predetermined voltage Ti can be between 0 and 1900 volts, with Ti < Tref. Generally, the actuation voltage depends on the properties of the electroactive material and the geometry of the fins. The characteristic electric fields can, for example, be on the order of a few tens of volts per micrometer of inter-electrode thickness.

[0125] Of course, other actuation mechanisms than the one described above may be used in the context of the invention. For example, the actuation mechanism may be an electrical actuation mechanism different from that described above (implemented, for example, by actuators located at the level of the fins), or it may be an actuation mechanism of another type, for example, mechanical, hydraulic, or magnetic. It is understood that for such actuation mechanisms, the fins 12 do not necessarily comprise an electroactive material.

[0126] An example of a hydraulic actuation mechanism is shown in [Fig. 11]. In this example, the rod 11 is a hollow rod, and the vanes 12 are attached to and pass through the rod 11, such that one end of each vane 12 is inside the rod 11 (in the hollow part) and the other end is outside the rod 11 (this other end is therefore located inside the blood vessel when the device is in place). To actuate the vanes 12 (i.e., to set the vanes 12 in motion), a flow of air or liquid is sent, via the control module 14 (which can, for example, control a pump), into the hollow rod 11. In this example, there is no particular constraint on the type of material of the vanes 12 (in particular, they need not necessarily comprise an electroactive material).

[0127] The actuation mechanism can also be magnetic. For example, the fins may include a ferromagnetic material and can be set in motion (i.e. actuated) by the application of a magnetic field.

[0128] Other implementations are of course possible.

[0129] Generally, in the context of the invention, it is noted that the fins 12 of the device 100 can be set in motion simultaneously, or in a slightly desynchronized manner in time.

[0130] Embodiments in which the fins 12 are set in motion simultaneously or slightly asynchronously are described below, in the context of the electrical actuation of [Fig. 1] (where the fins comprise an electroactive material). Of course, these two examples can be adapted to any type of actuation mechanism.

[0131] In embodiments where the fins 12 are set in motion simultaneously, the electrical power source 15 can be electrically connected to the fins 12 via electrical cables, and the electrical cables simultaneously carry an electrical voltage to all the fins 12. Other embodiments are possible. For example, the rod 11 can be made of a material comprising an electrically conductive membrane, and this electrically conductive membrane can be connected via an electrical cable to the electrical power source 15, so that, when an electric current flows through the electrical cable, all the fins 12 are subjected to this electric current.

[0132] In alternative embodiments, the fins 12 can be set in motion in a slightly asynchronous manner, so as to achieve a "domino" (or "cascade") effect, in order to reproduce a physiological pulse wave progressing through the circulation. For example, the electrical power source 15 can be electrically connected to the fins 12 via respective electrical cables, and each electrical cable carries the electrical voltage to a respective fin, offset from one another (similarly, in terms of overall movement, to intestinal peristalsis). Such embodiments are shown in [Fig. 10].

[0133] Figure 10 shows the rod 11 of the device 100 and four fins 12a, 12b, 12c, 12d connected to the rod 11. Fin 12a corresponds to the most upstream fin (with respect to the BC direction of blood flow in the blood vessel into which the device 100 is inserted) and fin 12d corresponds to the most downstream fin. As shown in Figure 10, the most upstream fin 12a is subjected to a predetermined value of electrical voltage at time tb. The fin 12b, which immediately follows fin 12b in the BC direction of blood flow, is then subjected to a predetermined value of electrical voltage at time t2 = 0 + At, with At > 0 (on the order of a few ms, for example between 5 and 150 ms). The fin 12c which immediately follows the fin 12a in the BC direction of the blood circulation is then subjected to the predetermined value of electrical tension at a time t3 = t2 + At.Finally, the downstream fin 12d is subjected to the predetermined value of electrical voltage at a time t4 = t3 + At. .

[0134] Thus, in these embodiments, the vanes located furthest upstream in the circulation begin to move first, followed by those downstream, all the way to the end of the device 100. Therefore, at the start of systole (or just before, or just after), the first level of vanes can be activated to displace a certain proportion of the blood column, then the second level of vanes can be activated, and so on down to the furthest downstream level, thereby generating a significant pulsatile flow and acting as an intravascular pump in series for the heart. Such a system mechanism also advantageously relieves the workload of the ventricles, allowing the native heart to rest and promoting its recovery.

[0135] As mentioned above and shown for example in Figures 3 and 10, the fins 12 of the device 100, when actuated, perform a "folding" movement towards the rod 11, in the direction of blood flow. Figure 4 shows the angle α between the "initial" position of a fin 12 (i.e., the position of the fin before being energized) and the "final" position of the fin 12 (i.e., the position of the fin after being energized). This angle is also called " "Angular displacement." To ensure sufficient mixing, this angle α is preferably greater than 60°, and even more preferably greater than 80°. For example, in some embodiments, the angle α may be between 80° and 130° relative to the rest position. It is understood that the fins may exhibit local curvatures when set in motion.

[0136] Fig. 2 represents a mechanical circulatory assistance device according to an embodiment of the invention inserted via the femoral route into the aorta.

[0137] This insertion can conventionally be used to provide systemic circulation support. In this application, the device 100 can be inserted via the femoral artery and guided against the flow to the aorta 21, in the direction of the aortic valve 22, without passing through it. Winglets 12 are present on at least part of the portion of the stem 11 located in the aorta 21 when the device 100 is in place. For this application, the device 100 may, for example, have a length of between 30 and 60 cm, and the portion including the wings 12 may have a length of between 10 and 30 cm. For example, the portion including the wings 12 may begin at a distance of between 2 and 10 cm from the end of the stem 11 closest to the aortic valve 22 when the device 100 is in place.

[0138] It is noted that in another embodiment intended for more serious cases, the device 100 can be inserted so as to pass through the aortic valve 22 as well as a left intraventricular portion of the heart 23. This allows for maximum unloading of the left heart chambers. In this embodiment, the device 100 may, for example, have a length of between 40 and 70 cm, and the portion comprising the fins 12 may have a length of between 20 and 40 cm. For example, the portion comprising the fins 12 may begin at a distance of between 2 and 5 cm from the end of the stem 11 located in the left ventricle when the device 100 is in place.

[0139] In these embodiments where the device 100 is intended to be inserted into the aorta (which has a diameter of approximately 3 cm in an adult), the stem 11 may have a diameter between 2 mm and 10 mm, for example between 2 mm and 6 mm. Each fin 12 may have a length between 6 mm and 12 mm, for example between 8 mm and 10 mm. Generally, for such an application, the total surface area of ​​the fins per level may advantageously be between 1 cm² and 2.5 cm².

[0140] Generally, the stem 11 may have a diameter between 1 mm and 10 mm, for example between 2 mm and 6 mm, and each fin may have a length between 50% and 75% of the radius of the blood vessel into which the device 100 is intended to be inserted. Generally, the device 100 may be such that the sum of the diameter of the stem 11 and the lengths of two fins 12 is the order of 75% (for example, between 70% and 90%) of the diameter of the blood vessel into which the device 100 is intended to be inserted.

[0141] It is noted that the mechanical circulatory support device 100 according to the invention can also be used for right heart assistance. For such use, the device 100 can be inserted similarly to a Swan-Ganz catheter into a large vein, such as the internal jugular vein, the femoral vein, or the subclavian vein. The device 100 can then be advanced into the right atrium and then the right ventricle to finally reside in the pulmonary artery. In this embodiment, fins 12 must be present on at least a portion of the stem 11 located in the right ventricle. Fins may also be present on at least a portion of the stem 11 located in the pulmonary artery. This allows for right heart function assistance.In this embodiment, the device 100 may, for example, have a length of between 30 and 50 cm, and the portion comprising the fins 12 may have a length of between 10 and 20 cm. For example, the portion comprising the fins 12 may start at a distance of between 2 and 5 cm from the end of the rod 11 located in the pulmonary artery when the device 100 is in place.

[0142] To facilitate insertion into the vessel, the stem and fins portion can be initially (i.e., before implantation) covered with a wrapper that holds the fins in place along the stem. The device thus wrapped can be inserted like a conventional catheter, for example, using a Desilet®. This wrapper can be removed once the stem is in place. For example, the wrapper can be a very thin, tubular film covering the stem (or at least the portion of the stem with fins). Once the device is in place, this wrapper is pulled towards the portion of the device opposite the end of the stem through which it is inserted into the vessel, and left in place (for example, rolled up along the electrical cable 16a) or cut away for removal.

[0143] Figure 6 represents a flowchart of a manufacturing process for a mechanical circulatory assistance device according to an embodiment of the invention.

[0144] During step 610, the fins can be manufactured. For example, the fins can have a thickness between 50 µm and 500 µm.

[0145] For example, the fins can be manufactured in the form of fin units, each fin unit corresponding to a fin level on the stem. Examples of such units 120 are shown in Figures 7a to 7f.

[0146] In [Fig. 7a], the fin unit 120 comprises two fins 121 and 122 arranged opposite each other. The fin unit further comprises an opening 17 for receiving the rod 11 of the device.

[0147] In [Fig. 7b], the fin unit 120 comprises three fins 121, 122 and 123 arranged in a star pattern. The fin unit also has an opening 17 for receiving the rod 11 of the device.

[0148] Similarly, the fin units shown in [Fig.7c], [Fig.7d] and [Fig.7e] comprise respectively 4, 5 and 6 fins arranged in a star shape, and an opening for receiving the rod of the device.

[0149] The fins shown in Figures 7a to 7d have a tapered shape at their free end (i.e., the end not intended to be connected to the stem). In other words, the shape of the fins of these units is thinned at the free end. Tests have indeed shown that such a profile significantly improves the blood flow generated by the fin deformation. In particular, the fins can have a substantially triangular shape, as in Figures 7a to 7d.

[0150] Of course, other shapes are possible. For example, the fin unit of [Fig.7f] comprises 4 fins arranged in a star shape, the shape of which is substantially rectangular.

[0151] It is noted that in the examples above, the fin units are "one-piece" with a cylindrical orifice in their middle. Furthermore, in the manufacturing method example of [Fig. 6], the fins are attached to the rod individually. The invention is not limited to such an implementation. For example, the fins could be separate elements, attached independently of each other to the rod of the device.

[0152] With further reference to [Fig.6], in a step 620, the fin units are inserted onto the rod through the fin unit orifices (elements 17 of Figures 7a and 7b).

[0153] During a step 630, the fin units are fixed to the rod, for example by a band around each fin unit by a locking system on either side of each fin unit.

[0154] Figure 5 shows an example of a locking system comprising locking rings (or washers). More specifically, Figure 5 shows a cross-sectional view of a mechanical circulatory assistance device in which the fins are fixed to the rod with locking rings, according to an embodiment of the invention.

[0155] As shown in [Fig. 5], two rings 18 are mounted on either side of each fin unit 120 and tightened against each other to fix the fin unit 120 to the stem 11. These rings 18 may advantageously have a domed shape and no sharp angles to facilitate insertion of the device into a blood vessel. Furthermore, the rings 18 may define a specific fin attachment angle (not necessarily perpendicular to the axis of the catheter).

[0156] Of course, other locking systems are conceivable. For example, the fins can be fixed to the rod by gluing, welding, etc.

[0157] With further reference to [Fig.6], in a step 640, the assembly thus obtained can be covered with one or more layers of biocompatible material(s) (and, when the actuation is electrical actuation, electrically insulating) to limit the risks of intravascular thrombosis.

[0158] Fig. 8 represents an example of a control module 14 of the mechanical circulatory assistance device, according to one embodiment of the invention.

[0159] In these embodiments, the control module 14 includes a computer 800, comprising a memory 801 for storing instructions enabling the implementation of the method of controlling the electrical energy source, and temporary data for carrying out different steps of the processes described above.

[0160] The computer 800 further comprises a circuit 802. This circuit can be, for example, a processor capable of interpreting instructions in the form of a computer program, an electronic card whose steps of the process of the invention are described in silicon, or a programmable electronic chip such as an FPGA chip (for "Field-Programmable Gate Array" in English).

[0161] The computer 800 may include an input interface 803 for receiving a cardiac signal or information relating to a systole, and an output interface 804 for providing a command to power on the fins.

[0162] Of course, the present invention is not limited to the embodiments described above by way of example, it extends to other variants.

[0163] For example, the device 100 such as that shown in [Fig. 1] can typically be used on a patient for short or medium-term periods, for example, for a period ranging from a few hours to a few days, in an intensive care unit, for example. In this context of use and in the case of electrical actuation, the control module 14 and / or the electrical power source 15 can be external to the patient (the winged rod is inserted into the patient's body, but the control module 14 and / or the electrical power source are outside the patient).

[0164] Alternatively, the device 100 can be adapted for long-term use, from several days to several months, or even several years. For such use, the device 100 can be entirely internal to the patient. The device 100 can thus comprise a housing 13 as shown in [Fig. 1], the housing being implanted subcutaneously in the patient (like a pacemaker or a port-a-cath®). In these embodiments, the electrical power source can be recharged, for example, via transcutaneous electromagnetic communication. In these embodiments, the device incorporates a system for obtaining a cardiac signal from the patient, for example, a photoplethysmography system, or electrodes—for example, epicardial surface electrodes adapted to measure electrical signals at the epicardial surface of the patient's heart.

[0165] Furthermore, it is noted that the circulatory support device according to the invention may include other elements and perform other functions than those described above. In particular, the circulatory support device according to the invention may include a balloon and a thermocouple electrode, similarly to a Swan-Ganz catheter, for measuring various parameters and performing hemodynamic monitoring.

Claims

Demands

1. A mechanical circulatory assistance device (100) comprising: - a rod (11) for insertion into a blood vessel; - a plurality of fins (12) attached to the rod (11); - a control module (14) connected to the plurality of fins, the control module (14) being configured to: • obtain information relating to the start of systole of a cardiac cycle; and • upon obtaining the information, command an actuation of the plurality of fins (12) so as to induce a displacement of the plurality of fins (12), the displacement being a folding of the plurality of fins (12) towards the rod (11) in a direction corresponding to a direction of blood flow in the blood vessel.

2. Device (100) according to the preceding claim, wherein the control module (14) is further configured to: - obtain a cardiac signal relating to a subject's cardiac activity; - determine information from the received cardiac signal.

3. Device (100) according to any one of the preceding claims, wherein the stem (11) and / or the plurality of fins (12) are covered with a layer of electrically insulating biocompatible material.

4. Device (100) according to any one of the preceding claims, wherein the plurality of fins (12) is arranged along a portion of the rod (11), said portion having a length between 10 cm and 30 cm.

5. Device (100) according to any one of the preceding claims, wherein the plurality of fins (12) is distributed over a plurality of levels, wherein the number of fins (12) per level is between 1 and 8.

6. Device (100) according to the preceding claim, wherein each level is spaced from a neighboring level by a fixed distance of between 0.5 cm and 2 cm.

7. Device (100) according to any one of the preceding claims, wherein each fin of the plurality of fins (12) has a length between 6 mm and 12 mm.

8. Device (100) according to any one of the preceding claims, wherein each fin of the plurality of fins (12) comprises a first end connected to the rod (11) and a second end called free opposite to the first end, wherein each fin of the plurality of fins (12) has a tapered shape at its free end.

9. Device (100) according to any one of the preceding claims, wherein the actuation of the fins is a mechanical, hydraulic, electrical and / or magnetic actuation.

10. Device (100) according to the preceding claim, wherein the actuation of the fins is electrically actuation, wherein the plurality of fins (12) comprises an electroactive material, wherein the control module (14) is connected to an electrical power source (15) and wherein the control of the actuation of the fins comprises: applying, via the electrical power source (15), a predetermined electrical voltage value to the plurality of fins (12) so as to induce a deformation of the plurality of fins (12), the displacement of the plurality of fins (12) resulting from said deformation of the plurality of fins (12).

11. Device (100) according to the preceding claim, wherein each fin (12) of the plurality of fins (12) comprises a layer of electroactive material having a first surface and a second surface, wherein the first surface is at least partially covered with a first layer of electrically conductive material, and the second surface is at least partially covered with a second layer of electrically conductive material, the first layer of electrically conductive material and the second layer of electrically conductive material being electrically insulated and each connected to the electrical power source (15).

12. Device (100) according to claim 10 or 11, wherein, prior to obtaining the information, no electrical voltage value is applied to the plurality of fins (12), wherein the predetermined value is strictly positive.

13. Device (100) according to claim 10 or 11, wherein the control module (14) is further configured to control an application, prior to obtaining information, of a reference electrical voltage value to the plurality of fins (12), the reference electrical voltage value being strictly greater than the predetermined value.

14. Method of manufacturing a mechanical circulatory assistance device (100) according to any one of the preceding claims, comprising: - obtaining a rod (11) for insertion into a blood vessel; - obtaining a plurality of fins (12); - attaching the plurality of fins (12) to the rod (11); - connecting the plurality of fins (12) to a control module (14).

15. A method according to the preceding claim, wherein the plurality of fins (12) comprises a set of fin units (120), each fin unit (120) comprising at least one fin (121, 122, 123) and an orifice (17), wherein the attachment of the plurality of fins (12) to the rod (11) comprises, for each fin unit (120): - inserting (620) the rod (11) into the orifice (17) of the fin unit (120); - attaching (630) the fin unit (120) to the rod (11) by means of a locking system (18).

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