Mechanical circulatory support device

Abstract

One aspect of the invention relates to a mechanical circulatory assistance device (100) comprising: a rod (11) intended to be inserted into a blood vessel; a plurality of fins (12) fixed 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; andupon obtaining the information, control an actuation of the plurality of fins (12) so as to induce a movement of the plurality of fins (12), the movement being a folding of the plurality of fins (12) towards the rod (11) in a direction corresponding to a direction of blood circulation 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 suffering from 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 a cardiac output adequate to 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 therapies. Indeed, heart failure is the leading cause of death worldwide.

[0004] The most serious pathology associated with heart failure is cardiogenic shock, defined by the inability of the ventricular pump to generate sufficient blood flow allowing the peripheral organs to meet their metabolic needs, with 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] Drugs that stimulate the contraction of the heart, 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 help avoid complications by restoring blood flow to other organs in place of the heart. These supports are installed temporarily, for example while the patient recovers his native cardiac function. In the absence of such recovery of native cardiac function, it is then necessary to refer the patient to a heart transplant project 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 counterpulsation balloon, the Abiomed Impella® heart pump, and veno-arterial extracorporeal membrane oxygenation (ECMO) systems. These devices have demonstrated only partial effectiveness in certain situations and are associated with numerous adverse effects and / or complications.

[0008] The intra-aortic counterpulsation balloon consists of inflating a balloon with gas in diastole and deflating it in systole. Its objective is to unload the left heart, the deflation of the balloon causing a drop in aortic pressure and aspiration of the ejected blood. However, this device has shown only limited effectiveness in physiological studies, particularly with regard to the generation of flow in patients with low cardiac output (an increase of only 15 to 20% compared to the initial flow). In addition, its use is associated with numerous complications, particularly vascular (risk of acute limb ischemia, vascular rupture and hemorrhage) and poor positioning of the balloon can cause mesenteric or even renal ischemia.Its indication is now being questioned and has been removed from European cardiology recommendations since the publication of a clinical trial conducted in 2012 and concluding that there was no significant improvement in prognosis in patients treated with an intra-aortic counterpulsation balloon compared to patients treated in a standard manner without an intra-aortic counterpulsation balloon.

[0009] The Impella® heart pump is an axial micro-pump introduced via the vascular route. There are three versions: a lightweight percutaneous version, a heavier version introduced surgically, and a version for right cavities that is rarely used and not available in France. Its positioning is difficult and often requires manipulation and installation in a catheterization room to obtain an X-ray view, which prevents its use at the patient's bedside. It therefore requires technical skill on the part of the practitioner and specific logistics, which means that it cannot be used for immediate stabilization of all patients. It also presents a significant risk of hemolysis, due to the need for blood to enter a miniaturized suction path in the left ventricle, then pass through a miniature pump rotating at high speed to be re-ejected into the aorta.Contact with red blood cells is therefore high and the risk of lysis (with its consequences of severe acute renal failure) is frequent. In addition, the actual flow rate is lower than the estimated flow rate and its effectiveness is often limited in its percutaneous version. The heavier version is more effective, but it requires a surgical approach 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 take breaks in order to assess the patient's weaning from the assistance device.

[0010] Veno-arterial ECMO is the assistance of choice for cardiogenic shock situations, given the generation of a very high flow rate of up to 4 or 5 liters, unloading the right cavities and reinjecting the blood into the aorta by retrograde route. This is a bi-ventricular assistance consisting of a cannula arterial and a venous cannula, which are connected to a circuit comprising an electric centrifugal pump and a membrane oxygenator. It can be implanted at the patient's bedside, in immediate emergency, even in cardiac arrest. However, due to the large size of the two cannulas, infections as well as 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 the oxygenator (for example, pump stoppage) are also relatively common.In addition, the electric centrifugal pump generates a continuous flow, which therefore does not respect the physiological flow, and this flow is reinjected the vast majority of the time by retrograde arterial femoral route, and therefore does not unload the left heart, thus promoting the appearance of pulmonary edema (a significant mortality factor in patients under veno-arterial ECMO) and the need to put the patient to sleep and ventilate him artificially.

[0011] There is therefore a need for temporary mechanical circulatory assistance devices which do not have or which limit the aforementioned drawbacks. 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 circulation 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 attached to the rod;

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

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

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

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

[0020] By "fin" is meant an element fixed to the rod, projecting from an external surface thereof. In other words, the fins extend from a lateral surface of the rod outwards (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", is meant any information related to a systole of a cardiac cycle. In particular, the information may indicate a start of systole. It is noted that, in this case, the information is not necessarily perfectly synchronized with a start of systole, but it may include an advance or a delay of the order of a few ms relative to the start of the 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 thus configured to trigger a movement of the fins. This movement causes the displacement of a volume of blood and the generation of a blood flow. Due to the synchronization with cardiac activity, the flow thus generated respects cardiovascular physiology, which generally improves the effectiveness of circulatory assistance and avoids undesirable effects for the patient.

[0024] It is noted that the circulatory assistance device according to the invention is very little concerned by the thrombotic risk, unlike Impella® or ECMO because it does not involve any passage of blood through a pump. The flow generated by the wings is physiological (it is synchronized with the flow generated by the patient's native heart) and it is antegrade (i.e. in the "natural" direction of blood circulation), which greatly reduces the risk of pulmonary edema occurring. In addition, the placement 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 fails (electrical problem, incorrect handling, etc.), the blood flow can continue to circulate around the wings and avoid serious injuries.

[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 down", it is understood that the free end of the fins (i.e. the end opposite the end connected to the rod) folds down towards the rod. In other words, the fins perform an angular movement, in the direction of blood circulation.

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

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

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

[0030] - obtaining a cardiac signal relating 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 the subject's cardiac activity, 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 may 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 assistance device may integrate a cardiac activity measurement system. In the case of an ECG system, the device may further comprise electrodes connected to the control module and configured to measure cardiac electrical signals relating to cardiac electrical activity of the subject. The control module may further be configured to determine the electrocardiogram signal from the received cardiac electrical signals.

[0034] Alternatively, the information may be determined by an external device (e.g., a cardiac activity measurement system) and sent to the control module.

[0035] In one or more embodiments, the rod 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 are disposed along a portion of the rod, said portion having a length of between 10 cm and 30 cm.

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

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

[0040] Furthermore, for each level of the plurality of levels, the fins of the level may be uniformly distributed around the rod. This allows the flow to be well distributed all around the rod, and prevents the rod 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 may be constant. In other words, for each level, the number of fins may be the same.

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

[0043] In other words, each fin of a 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 more even blood flow, thereby reducing the risk of clots or endovascular injury.

[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 neighboring levels is fixed.

[0047] In one or more embodiments, each fin of the plurality of fins has a length of 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 rod and a second so-called free end opposite the first end, wherein 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 of the plurality of fins may be flared at its first end (i.e., in the example of [Fig.7a] to 7f, at the embedding in the rod, i.e. at the orifice 17) and narrowed towards its free end. For example, the shape of each fin of the plurality of fins may be substantially triangular (or of 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 a protruding angle).

[0054] The actuation of the fins can be mechanical, hydraulic, electric 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 energy source and the control of the actuation of the fins comprises: applying, via the electrical energy 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 which deforms under the application of an electric field. Such electroactive materials include in particular electroactive polymers (PEA), 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 electrically energized, these fins move so as to generate blood flow in the same direction as blood circulation, and thus assist cardiac function.

[0058] According to the embodiments, the electrical energy source may be integrated into a housing forming part of the device (and integrating the control module and the energy source) or may 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, before obtaining the information, no electrical voltage value is applied to the plurality of fins, wherein 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 remainder of the cardiac cycle), and a non-zero electrical voltage is applied to the plurality of fins when obtaining the information relating to the systole.

[0063] Alternatively, the control module is further configured to control the electrical energy source for controlling an application, before obtaining the 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 base” to the plurality of fins, and an electrical voltage Ti strictly lower than Tref (Ti may or may not be zero) is applied to the plurality of fins to obtain the information relating to the systole.

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

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

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

[0068] - upon obtaining the information, controlling 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 circulation in the blood vessel.

[0069] The present invention also relates to a computer program comprising instructions for implementing certain steps of the above method, 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 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 of manufacturing a mechanical circulatory assistance device defined above, comprising:

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

[0073] - obtaining a plurality of fins, the plurality of fins comprising an electrical material reactive;

[0074] - attaching the plurality of fins to the rod;

[0075] - connecting 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 an orifice, wherein attaching the plurality of fins to the rod comprises, for each fin unit:

[0077] - insert the rod into the hole 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 single reference. BRIEF DESCRIPTION OF THE FIGURES

[0080] Other characteristics and advantages of the invention will appear on reading the description, which can be read with reference to the figures. These figures are presented for information purposes only and in no way limit the invention.

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

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

[0083] [Fig. 3] represents the movement of the fins 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 sectional view of a mechanical circulatory assistance device according to one embodiment of the invention.

[0086] [Fig.6] represents a flowchart of a method of manufacturing a mechanical circulatory assistance device according to one embodiment of the invention.

[0087] Figures 7a to 7f represent several examples of fins usable in the context of the present invention.

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

[0089] [Fig.9] represents an example of 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 fins in cascade, according to an 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.l] represents a mechanical circulatory assistance device according to one embodiment of the invention.

[0093] The mechanical circulatory assistance device 100 (hereinafter simply called “device”) according to the invention comprises a rod 11, on which a plurality of fins 12 (or “petals”) are mounted.

[0094] The rod 11 may be a “solid” rod or a “hollow” rod. By “solid” rod, it is understood that the rod may comprise certain elements, for example electrical cables, but that it is not intended to receive fluid or medical devices (such as a probe). This means in particular that a “solid” rod is not intended to be used as a conventional catheter. Alternatively, the rod may be “hollow”, to receive a fluid or a medical device such as a probe. In this alternative, the device 100 may also perform a role of catheter, and be used to administer a product (for example an intravenous medication, a contrast product, a solute) to the patient, to pass a probe or another medical device or to remove excess liquid abnormally present in a cavity (drainage).In particular, the device 100 may be used as a Swan-Ganz catheter to measure pressures and flows in the right heart chambers and the pulmonary artery (“straight” catheterization). In this case, the device may be inserted (similar to the Swan-Ganz catheter) via a large-bore vein—such as the internal jugular vein, the femoral vein, or the subclavian vein—and slid into the right atrium and then the right ventricle, finally residing in the pulmonary artery.

[0095] Similar to a catheter, the rod 11 is intended to be inserted into a vessel (for example, a large vein or an artery). Thus, the rod 11 is made of a material that is sufficiently flexible to be able to be inserted into the vessel without causing injury. It is noted that the rod 11 must still be sufficiently rigid to be able to be simply inserted and remain in place once installed. Thus, the rod 11 is made of a material typically used for standard catheters. For example, the rod 11 may be made of a polymer material or a plastic material. In particular, the material of the rod 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 rod is not made of a biocompatible material (for example a latex rod), the entire rod 11 and fins 12 may be covered with one (or more) layer(s) of biocompatible material, so that the device 100 is well supported by the body. In addition, this (or these) layer(s) of biocompatible material may be electrically insulating, to limit the voltage applied to the fins 12 (and possibly the rod 11).

[0096] The fins 12 are elements arranged projecting along a portion P of the rod 11. For example, the fins 12 can be arranged in “levels” (or “stages”), with one or more 12 fins per level. The number of 12 fins 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 distributed uniformly by level (i.e. be distributed uniformly around the rod, which means that the angle between neighboring fins of the same level is constant). This allows a good balance of the distribution of blood flow all around the rod, and prevents the rod from becoming off-center relative to the blood vessel in which it is inserted (conversely, if all the fins are on one side of the rod, there is a risk that the rod will stick to the opposite wall of the blood vessel).

[0098] The levels may be equidistant from each other, for example spaced by a fixed distance of between 0.5 cm and 2 cm, preferably between 0.8 cm and 1.5 cm. Depending on the insertion route and the final positioning of the device 100, the portion P of the rod 11 may have a length of between 10 and 30 cm. The number of levels may thus be, for example, between 5 and 50, preferably between 10 and 30. In the example of [Fig.l], the fins 12 are arranged on 8 levels equidistant from each other, 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 conceivable 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 0 relative to the fins of level L1, 0 corresponding to half the angle between two neighboring 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 injuries.

[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.l], to set the fins 12 in motion, the device 100 further comprises a control module 14. As described below with reference to [Fig.8], the control module 14 notably comprises a processor. The term “processor” designates, in the present application, a single processor or a multitude of processors. For example, each processor may be dedicated to one task among the tasks necessary for the operation of the device 100 or a 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 to command, upon obtaining this information, an actuation of the vanes 12. The actuation of the vanes 12 makes it possible to set them in motion, and this movement of the vanes makes it possible to assist blood circulation and to increase 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 embodiments, a particular embodiment of which is shown in [Fig.l], the actuation of the fins 12 is an electrical actuation, and the control module 14 is connected to an electrical energy source 15 via an electrical cable 16a. In the embodiment of [Fig.l], the electrical energy source is part of the device 100, and the control module 14 and the electrical energy source 15 are both integrated in a housing 13 (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 electrical energy source 15 external to the device. It is noted that the housing 13 is optional.Such a case is of interest when the device 100 is intended to be implanted completely internally in the patient (for long-term use), but it is optional when the device 100 is intended to “come out” of 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 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 relaxor material of the PVDF-TrFE-CFE terpolymer type, also noted 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, with 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 fins 12 made of electroactive material of the device 100 are intended to perform a flexion movement during the cardiac contraction phase, in systole. This flexion movement is carried out in the direction of circulation of the blood in the vessel in which the device 100 is inserted, that is to say that the movement of the fins 12 “accompanies” the circulation of the blood in the vessel. At the moment of cardiac contraction (i.e. at the start of systole), the fins 12 thus begin to move, thus promoting the expulsion of blood into the arteries, towards the various organs.

[0109] The fins may be made of a material exhibiting a compromise between a large relative deformation under an electric field and a significant blocking force. Indeed, the fins must deform sufficiently to induce a movement to assist the circulation of the blood, but must have a sufficient blocking force to have sufficient resistance compared to the resistance of the medium in which they are intended to be used (the interior of a blood vessel, in which the blood circulates). It is recalled that the blocking force of a material corresponds to the limiting force to be applied to the material to prevent its deformation or movement.

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

[0111] The electrical energy source 15 may be, for example, an electric battery which powers the control module 14 via the electric cable 16a. The electric cable(s) 16b make it possible to connect the control module 14 and / or the electrical energy source to the fins 12, in order to allow the control module 14 to control 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 pulse lasting 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 start 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 module command can receive this information or determine it.

[0114] For example, according to one embodiment, the control module 14 may 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 [Fig.l], the control module 14 is configured to control, upon receipt of the information from the external device, the electrical energy source 15 to apply the predetermined value T of electrical voltage to the fins 12. The external device may be any device for obtaining a cardiac signal, for example an electrocardiogram (ECG) device, and configured to determine the information from the obtained cardiac signal and send it to the circulatory support device 100.

[0115] According to another embodiment, the control module 14 can be configured to receive a cardiac signal relating to a cardiac activity of the subject, and to determine, from this cardiac signal, the information 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.l], it is the control module 14 which determines the information from the cardiac signal, and no longer the external device. The cardiac signal can also be received from a system for determining a cardiac signal 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 relating to a cardiac activity of the subject and determine information from the determined cardiac signal. For example, the device 100 can include a system for determining a cardiac signal, such as a photoplethysmography system. According to another example, the device 100 can be connected to electrodes placed on the patient and configured to measure signals, and the control module 14 can process the signals measured by the electrodes to construct the ECG signal, and then determine the information.

[0117] The cardiac signal may be, for example, an electrocardiogram (ECG) signal, but also a cardiac signal obtained by other techniques, for example by photoplethysmography (signal relating to heart rate), by cardiac echo-Doppler, by blood pressure measurement, etc. In general, the cardiac signal may be any signal relating to the patient's cardiac cycle and making it possible to determine the start of systole.

[0118] The information obtained is information relating to a systole of a cardiac cycle. Thus, as shown in [Fig.3], at each systole, the control module 14 controls the actuation of the fins 12 to put them in movement. In the example of the electrical actuation above, the control module 14 can thus command, at each systole, that a predetermined value of electrical voltage is applied to the fins 12, which then fold back towards the rod 11, in the direction BC of the blood circulation in the vessel in 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 is recalled that an electrocardiogram (ECG) signal measures the electrical activity of the subject's heart, and includes different characteristic events, represented in [Fig.3]: • The P wave, which corresponds to the depolarization wave of the atria. It represents the electrical impulse which originates in the sinus node and which passes through the atria, causing them to contract. The contraction of the atria allows the passage of blood from the atria to the ventricles through the tricuspid and mitral valves. The electrical wave continues its path to the atrioventricular node; • The PR space or PQ space, 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 to 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 through the bundle of His and its branches and causes the contraction of the ventricles; • The ST segment, which corresponds to the start of repolarization of the ventricles; • The T wave, which is the repolarization wave of the ventricles. The 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 vanes are set in motion via the control module 14 (for example by applying a predetermined value of electrical voltage to the vanes 12).

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

[0123] For example, according to one embodiment, no electrical voltage is applied outside of the start 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 electrical voltage is equal to a non-zero value Tref, and, when determining the information relating to a systole, an electrical voltage of predetermined value Ti is applied, with Ti < Tref. For example, the reference value Tref can be between 10 and 2000 volts and the predetermined electrical voltage value Ti can be between 0 and 1900 volts, with Ti < Tref. Generally speaking, the actuating electrical voltage depends on the properties of the electroactive material and the geometry of the fins. The characteristic electric fields can be, for example, of the order of a few tens of volts per micrometer of inter-electrode thickness.

[0125] Of course, other actuation mechanisms than that 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 fins), or 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.l 1]. In this example, the rod 11 is a hollow rod, and the fins 12 are fixed to the rod 11 and pass through the rod 11, so that one end of each fin 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 fins 12 (i.e. to put the fins 12 in movement), a flow of air or liquid is sent, via the control module 14 (which can for example control a pump), inside the hollow rod 11. In this example, there is no particular constraint on the type of material of the fins 12 (in particular, they do not necessarily have to comprise an electroactive material).

[0127] The actuating mechanism may also be magnetic. For example, the vanes may comprise a ferromagnetic material and may be set in motion (i.e. actuated) by applying a magnetic field.

[0128] Other implementations are of course possible.

[0129] Generally speaking, 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 out of sync in time are described below, in the context of the electrical actuation of [Fig.l] (case where the fins comprise an electroactive material). Of course, these two examples can be adapted to any type of actuation mechanisms.

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

[0132] In alternative embodiments, the vanes 12 may be set in motion slightly out of sync in time, so as to achieve a "domino" (or "cascade") effect, to mimic a physiological pulse wave progressing through the circulation. For example, the electrical power source 15 may be electrically connected to the vanes 12 via respective electrical cables, and each electrical cable carries the electrical voltage to a respective vane, offset from each other (similar, in terms of overall motion, to intestinal peristalsis). Such embodiments are shown in [Fig. 10].

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

[0134] Thus, in these embodiments, the fins located furthest upstream in the circulation start moving first, then those downstream, up to the end of the device 100. Thus, at the start of systole (or just before, or just after), the first level of fins can thus be activated to move the column of blood to a certain proportion, then the second level of fins can be activated, and so on up to the level located furthest downstream, thus generating a significant pulsatile flow and acting as a serial intravascular pump of the heart. Such a system mechanism also advantageously offloads the work of the ventricles, allowing the native heart to be put 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 perform, when they are actuated, a “folding” movement towards the rod 11, in the direction of blood circulation. [Fig. 4] represents 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 a sufficient mixing effect, this angle α is preferably greater than 60°, and even more preferably greater than 80°. For example, in certain embodiments, the angle α may be between 80° and 130° relative to the rest position. It is understood that the fins may have local curvatures when they are 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 be conventionally used to provide assistance to the systemic circulation. In this use, the device 100 can be inserted via the femoral route and guided against the flow to the aorta 21, towards the aortic valve 22, without crossing the latter. Wings 12 are present on at least part of the portion of the rod 11 located in the aorta 21 when the device 100 is in place. For this use, the device 100 can for example have a length of between 30 and 60 cm, and the portion comprising the fins 12 may have a length of between 10 and 30 cm. For example, the portion comprising the fins 12 may start 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 cross the aortic valve 22 as well as a left intra-ventricular portion of the heart 23. This makes it possible to unload the left heart chambers as much as possible. In this embodiment, the device 100 can for example have a length of between 40 and 70 cm, and the portion comprising the fins 12 can have a length of between 20 and 40 cm. For example, the portion comprising the fins 12 can start at a distance of between 2 and 5 cm from the end of the rod 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 (the diameter of which is approximately 3 cm for an adult), the rod 11 may have a diameter of between 2 mm and 10 mm, for example between 2 mm and 6 mm. Each fin 12 may have a length of between 6 mm and 12 mm, for example between 8 mm and 10 mm. Generally, for such use, the total surface area of ​​the fins per level may advantageously be between 1 cm2 and 2.5 cm2.

[0140] Generally, the rod 11 may have a diameter of between 1 mm and 10 mm, for example between 2 mm and 6 mm, and each fin may have a length of 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 value of the sum of the diameter of the rod 11 and two lengths of fins 12 is of 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 assistance device 100 according to the invention can also be used for assistance of the right circulation. For such use, the device 100 can be inserted in a manner similar to a Swan Ganz catheter, at the level of a large caliber vein, such as the internal jugular vein, the femoral vein or the subclavian vein. The device 100 can then be slid into the right atrium then the right ventricle to finally reside in the pulmonary artery. In this embodiment, fins 12 must be present on at least a part of the portion of the rod 11 located in the right ventricle. Fins may further be present on at least a part of the portion of the rod 11 located in the pulmonary artery. This makes it possible to assist the right heart function.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 between 10 and 20 cm. For example, the portion comprising the fins 12 may start at a distance 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 be able to be easily inserted into the vessel, the “rod and fins” part may be initially (i.e. before its implantation) covered with a packaging allowing the fins to be “pressed” along the rod. The device thus packaged may be inserted like a conventional catheter, for example using a desilet®. This packaging may be removed once the rod is in place. For example, the packaging may be a very thin film of tubular shape and covering the rod (or at least the part of the rod on which fins are present), and once the device is in place, this packaging is “pulled” towards the part of the device opposite the end of the rod by which the latter is inserted into the vessel, and left in place (for example rolled up along the electric cable 16a) or cut to be removed.

[0143] [Fig.6] represents a flowchart of a method of manufacturing a mechanical circulatory assistance device according to one embodiment of the invention.

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

[0145] For example, the fins may be fabricated as fin units, each fin unit corresponding to a fin level on the stem. Examples of such units 120 are shown in Figures 7a-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 orifice 17 intended to receive 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 shape. The fin unit also has an orifice 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 orifice intended to receive the rod of the device.

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

[0151] It is noted that in the above examples, the fin units are "one-piece" with a cylindrical orifice in their middle. Furthermore, in the exemplary manufacturing method of [Fig.6], the fins are attached to the rod in units. 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] Referring again 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 strapping each fin unit with a locking system on either side of each fin unit.

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

[0155] In the example of [Fig.5], two rings 18 are mounted on either side of each fin unit 120 and clamped against each other to fix the fin unit 120 on the rod 11. These rings 18 can advantageously have a curved shape and without a protruding angle, to facilitate the insertion of the device into a blood vessel. In addition, the rings 18 can define a particular angle of fixation of the fins (not necessarily perpendicular to the axis of the catheter).

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

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

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

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

[0160] The computer 800 further comprises a circuit 802. This circuit may be, for example, a processor capable of interpreting instructions in the form of a computer program, an electronic card whose steps of the method of the invention are described in the silicon, or even 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 energize the fins.

[0162] Of course, the present invention is not limited to the embodiments described above as examples, it extends to other variants.

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

[0164] Alternatively, the device 100 may be adapted to be used over a long period, from several days to several months, or even several years. For such use, the device 100 may be entirely internal to the patient. The device 100 may thus comprise a housing 13 as shown in [Fig.l], the housing being implanted subcutaneously in the patient (like a pacemaker or a port-a-cath®). In these embodiments, the electrical energy source may be recharged, for example, by transcutaneous electromagnetic means. In these embodiments, the device integrates 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 comprise other elements and provide other functions than those described above. In particular, the circulatory support device according to the invention may comprise a balloon and a thermocouple electrode, similarly to a Swan Ganz catheter, for measuring various parameters and performing hemodynamic monitoring.

Claims

Claims

1. A mechanical circulatory assistance device (100) comprising: - a rod (11) intended to be inserted into a blood vessel; - a plurality of fins (12) fixed 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 a systole of a cardiac cycle; and • upon obtaining the information, control an actuation of the plurality of fins (12) so as to induce a movement of the plurality of fins (12), the movement being a folding of the plurality of fins (12) towards the rod (11) in a direction corresponding to a direction of blood circulation 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 cardiac activity of a subject; - determine the information from the received cardiac signal.

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

4. Device (100) according to 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 of between 10 cm and 30 cm.

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

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

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

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

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

10. Device (100) according to the preceding claim, wherein the actuation of the fins is an electrical actuation, wherein the plurality of fins (12) comprises an electroactive material, wherein the control module (14) is connected to an electrical energy source (15) and wherein the control of the actuation of the fins comprises: applying, via the electrical energy 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. The device (100) of 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 energy source (15).

12. Device (100) according to one of the preceding claims, in which, before obtaining the information, no electrical voltage value is applied to the plurality of fins (12), in which the predetermined value is strictly positive.

13. Device (100) according to one of claims 1 to 11, in which the control module (14) is further configured to control an application, before obtaining the 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. finished.

14. A method of manufacturing a mechanical circulatory assistance device (100) according to one of the preceding claims, comprising: - obtaining a rod (11) intended to be inserted into a blood vessel; - obtaining a plurality of fins (12), the plurality of fins (12) comprising an electroactive material; - fixing 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 attaching 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) using a locking system (18).

Images