FR3004111A1 - LEFT VENTRICULAR HEART SUPPORT PUMP - Google Patents

Abstract

A left ventricular cardiac assist pump, having an inlet opening (18) and a discharge opening (20) aligned in an axial direction, said pump having a casing (11) radially spaced from the stator (13) and the turbine (16), with at least one spacer (14) connecting the casing (11) and the stator (13); the turbine (16) being configured to drive blood to the casing (11) and to the discharge opening (20), whereby the blood circulates in said pump essentially between the casing (11) and the rotor unit -stator (15).

Description

The invention relates to left ventricular cardiac assistance. It is known that the human heart has a right ventricle which is used for the circulation of venous blood (blue blood) and a left ventricle which is used for the circulation of arterial blood (red blood). Blood from the venous system enters the right ventricle and leaves it through the pulmonary artery, which carries venous blood to the lungs. At the exit of the lungs, the oxygenated blood returns to the heart by the pulmonary veins, arrives in the left ventricle and leaves it by the aorta which takes the arterial blood towards the arterial system.

In the vast majority of cases, cardiac deficiencies are caused by the left ventricle. It is known to use a pump to assist the heart, in order to circulate the blood instead of the left ventricle. This pump is part of a branch arranged in parallel with the left ventricle.

Such a branch comprises, in addition to the pump, an upstream duct, one end of which is connected to the left ventricular tip and the other end to the inlet opening of the pump, and a downstream duct whose one end is connected to the discharge opening of the pump and the other end to the aorta at the exit of the left ventricle.

Various types of pump are already known for performing left ventricular cardiac assistance, in particular centrifugal pumps whose inlet opening and discharge opening are arranged transversely to one another; and worm gear pumps whose inlet opening and discharge opening are aligned in an axial direction. US patent application US 2012/0134832 discloses a cardiac assist pump having a rotor having a turbine and a shaft provided with electric motor magnets and a casing having an inlet opening and a discharge opening aligned in one direction. axial, this envelope comprising a stator portion disposed around the rotor shaft, provided with stator windings of electric motor, cooperating with the magnets of the rotor shaft to drive it in rotation. The aim of the invention is to provide a left ventricular cardiac assist pump that offers both good electrical performance and good hydraulic performance.

The invention proposes for this purpose a left ventricular cardiac assist pump, comprising an inlet opening and a discharge opening aligned in an axial direction, said pump comprising: a rotor comprising a turbine and a shaft provided with magnets electric motor; and a stator disposed around said shaft provided with stator windings of an electric motor; characterized in that: - said pump comprises a separate envelope of said stator radially distant from said stator and said turbine, with the rotor and the stator forming a rotor-stator group surrounded by the casing, with at least one connecting spacer between the envelope and the stator; said casing being tubular and delimiting said inlet opening and said discharge opening of the pump; and - the turbine is configured to drive blood to the casing and to the discharge opening, whereby the blood circulates in said pump essentially between the casing and the rotor-stator unit. Since the casing is distinct from the stator and surrounds the rotor-stator group, it is possible to provide a large passage section between the casing and the rotor-stator group; and a very small gap between the rotor and the stator of the rotor-stator group. This benefits both a good circulation of blood through the large section of passage between the casing and the rotor-stator group, and a good electromagnetic cooperation between the stator and the rotor, thanks to their proximity. In addition to the large section of passage between the casing and the rotor-stator group favorable to the flow of blood, the pump according to the invention is particularly well suited to entrain the blood since therein there is there is no sudden change of direction and the technology of the turbine, which is centrifugal type since the blood is driven towards the envelope, is relatively soft. Thus, the risks of hemolysis (destruction of red blood cells) and thrombosis (clot formation) are minimized. According to advantageous features of implementation of the rotor-stator group: the rotor-stator group is generally spindle-shaped; the rotor comprises an upstream head connected to the shaft on the side of the inlet opening, said upstream head having an annular top on either side of which extend respectively an upstream face on the side of the opening of the inlet and a downstream face on the side of the shaft, said upstream face forming said turbine; the upstream face of the upstream head has blades projecting from a surface whose diameter decreases from the top to the upstream end of the rotor; the downstream face of the upstream head has a surface whose diameter decreases from the top to the shaft, the stator having on the inlet opening side an upstream inclined surface such as the surface of the downstream face of the upstream head, with behind the surface of the downstream face of the upstream head magnets upstream of electromagnetic palliation and behind the upstream surface of the stator windings upstream of electromagnetic plateau; the rotor comprises a downstream head connected to the shaft on the discharge opening side, said downstream head having an annular top on either side of which extend respectively an upstream face on the side of the shaft and a downstream face on the discharge opening side, the upstream face having a surface whose diameter decreases from the top to the shaft, the stator having on the discharge opening side a downstream surface inclined as the surface from the upstream face of the downstream head, behind the surface of the upstream face of the downstream head of the electromagnetic bearing bottom magnets and behind the downstream surface of the stator of the electromagnetic bearing downstream windings; the upstream face of the upstream head has a surface whose diameter decreases from the annular top to the upstream end of the rotor, the envelope comprising a divergent portion facing the upstream face of the upstream head with behind the surface of the upstream face of the upstream head of electromagnetic bearing magnets and behind the inner surface of the diverging portion of the envelope of the electromagnetic bearing windings; and / or the upstream face of the upstream head has a surface whose diameter decreases from the annular apex to the upstream end of the rotor, said pump comprising a bearing surface on which the upstream end of the rotor rests, said bearing being secured to the envelope by arms. According to advantageous characteristics of implementation of the pump: - said casing is formed by a solid wall with permanent rigidity and each said connecting spacer is formed by a solid wall with permanent rigidity; said envelope comprises a divergent portion, a straight portion and a convergent portion, with the straight portion extending between the divergent portion and the converging portion, the divergent portion extending from an inlet end delimiting said opening. admission to said right portion, and the convergent portion extending from the straight portion to a discharge end defining said discharge opening; and / or - said envelope is provided externally with eyelets for retaining threads. According to alternative advantageous features of implementation of the pump: - said casing is formed by a wall made of an elastic memory material and each said connecting spacer is formed by a wall made of an elastic memory material ; and / or the rotor has a bore extending from an upstream end to a downstream end. According to other advantageous features of implementation of the pump: - an electric cable runs along said spacer; and / or - each said connecting spacer is helical and extends along said stator. The description of the invention will now be continued by the description of exemplary embodiments, given below by way of illustration and not limitation, in support of the accompanying drawings. On these: - Figure 1 is a sectional view of a left ventricular cardiac assist pump according to the invention, wherein the rotor-stator group is shown in detail while the envelope is shown in a detailed manner; schematic and the same for the connecting struts between the envelope and the stator; - Figure 2 is a view similar to Figure 1 but showing in detail the envelope and the connecting struts of a first practical embodiment of the pump according to the invention; and showing a connection connection to a portion of aorta in place on each end of the casing for the pump and fittings to form a pumping unit; FIG. 3 is a perspective view of the stator and the connecting struts of the pump shown in FIG. 2; FIG. 4 is a perspective view of the pump rotor shown in FIG. 2; - Figure 5 is a view similar to Figure 2, showing a variant of the rotational mounting elements of the rotor, involving not only the stator and the rotor but also the envelope; - Figures 6 and 7 are views similar to Figures 3 and 4, but for the stator and the pump rotor shown in Figure 5; - Figure 8 is a view similar to Figure 5, showing another variant of the rotational mounting elements of the rotor, involving a stop between the turbine and the casing; - Figure 9 is a view similar to Figure 2, showing a variant of the connecting struts; FIG. 10 is a perspective view of the heart of a patient and the arteries connecting to the heart, in this case the coronary arteries, the pulmonary artery and the aorta; - Figure 11 is a view similar to Figure 10 but with a portion of the aorta that has been removed; - Figure 12 is a view similar to Figure 11 but with the pump according to the invention implanted at the location of the aorta section removed; FIG. 13 is a schematic view of a patient, showing the implanted pump as well as the pump electrical supply cable and the patient's external equipment including a battery and an electronic control module of the pump; - Figure 14 is a view similar to Figure 2, showing a variant of the envelope, externally provided with eyelets for retaining son; Figure 15 is a view similar to Figure 12 but for the pump shown in Figure 14, also showing the sternum of the patient and the retaining wires of the sternum pump; - Figure 16 is a view similar to Figure 2 but with connections of different size; FIG. 17 is a schematic view of an assembly made available to surgeons for implanting the pump shown in FIGS. 2 and 16, this assembly comprising this pump and a set of four connection connectors, two of which have a size and the other two another size; FIG. 18 is a view similar to FIG. 13 for a variant implantation of the pump not in series with the left ventricle instead of a portion of the aorta but in parallel with the left ventricle between the tip; left ventricle and aorta; - Figure 19 is a view similar to Figure 1 but showing in detail the envelope and the connecting struts of a second practical embodiment of the pump according to the invention; FIG. 20 is a perspective view of the aorta of a patient in which the pump shown in FIG. 19 is implanted, with tearing of the wall of the aorta to show the pump; FIG. 21 is a diagrammatic view of an assembly made available to surgeons for implanting the pump shown in FIGS. 19 and 20, including this pump and elements enabling it to be placed in the aorta of a patient; FIG. 22 is a perspective view of a patient, showing the placement of the pump in a portion of the aorta; and FIG. 23 is a schematic view of a patient showing the implanted pump as well as the pump electrical supply cable and the patient's external equipment including a battery and an electronic control module of the pump. The pump 10 illustrated in FIG. 1 comprises a tubular casing 11, a rotor 12, a stator 13 and spacers 14 for connection between the casing 11 and the stator 13. The rotor 12 and the stator 13 form a rotor-rotor unit. stator 15, which is here generally spindle-shaped. The rotor 12 comprises a turbine 16 and a shaft 17. The stator 13 is disposed around the shaft 17, in the immediate vicinity of the shaft 17 and more generally of the rotor 12. The casing 11 is arranged around the rotor unit -stator 15, being radially distant from the stator 13 and the turbine 16. The envelope 11 has on the side that is seen below in Figure 1 an intake opening 18. In operation, the blood enters the pump 10 through the inlet opening 18. The inlet opening 18 is delimited by an inlet end 19 of the casing 11. 3004 1 1 1 8 On the side that is seen at the top on the 1, the casing 11 has a discharge opening 20. In operation, the blood leaves the pump 10 through the discharge opening 20. The discharge opening 20 is delimited by a discharge end 21 of the casing 11. The inlet opening 18 and the discharge opening 20 are aligned in the axial direction . In general, the pump 10 is configured so that blood flows between the inlet opening 18 and the discharge opening 20 substantially between the casing 11 and the rotor-stator group 15. There is also a minimal circulation of the blood inside the rotor-stator group 15, that is to say between the rotor 12 and the stator 13. In FIG. 1, the flow of blood essentially between the casing 11 and the rotor group -stator 15 as well as the minimal blood circulation between the rotor 12 and the stator 13 are represented by arrows. It will be observed that the difference between the casing 11 and the rotor-stator group 15 is much greater than the difference between the rotor 12 and the stator 13. This allows both good circulation of the blood inside. of the pump 10, thanks to the large passage section between the casing 11 and the rotor-stator group 15, and a good electromagnetic cooperation between the stator 13 and the rotor 12, thanks to the immediate proximity between the stator 13 and the rotor 12. The shaft 17 of the rotor 12 is provided with magnets 25 of the electric motor. The stator 13 comprises, in line with the magnets 25, windings 26 of the electric motor. The magnets 25 and the windings 26 serve to drive the rotor 12 in rotation, in a manner well known to electric motor technicians. The fact that the rotor 12 comprises simple magnets avoids having to supply electricity to the rotor 12. Only the windings 26 of the stator 13 must be supplied with electricity. 3004 1 1 1 9 The conformation of the rotor 12 and the conformation of the stator 13 will be described in more detail later with reference to FIGS. 3 and 4. The pump 10 is provided to be secured by the envelope 11 to the patient on which it must be implanted. The spacers 14 rigidly hold the stator 13 to the casing 11. For the power supply of the rotor-stator unit 15, and more precisely here for the supply of the windings 26 and other windings of the stator 13, an electric cable 31 runs along one of the spacers 14. The electrical cable 31 is shown only in FIG. 1 to simplify the drawings. Referring now to FIGS. 2 to 4, a first practical embodiment of the pump 10, in which the casing 11 is formed by a solid wall 35 with permanent rigidity and in which the connecting struts 14 are each formed by a solid wall 36 with permanent rigidity. In this first embodiment, the envelope 11 comprises a diverging portion 37, a straight portion 38 and a convergent portion 39. The straight portion 38 extends between the divergent portion 37 and the convergent portion 39. The divergent portion 37 extends from the inlet end 19 to the straight portion 38. The convergent portion 39 extends from the straight portion 38 to the discharge end 21. The rotor-stator group 15 is held by the spacers 14 centered 25 vis-à-vis the casing 11 both radially and axially. The inlet opening 18 and the discharge opening 20 have the same diameter. The divergent portion 37, the straight portion 38 and the convergent portion 39 are configured so that the radial gap between the casing 11 and the rotor-stator group 15 remains substantially constant. Thus, from the inlet opening 18 to the discharge opening 20, the passage section between the rotor-stator group and the casing 11 remains substantially constant. 3004 1 1 1 10 The intake end 19 has a tapping 40 (Figure 17). The discharge end 21 has a tapping 41 (Figure 17). The tapping 40 is used to set up on the casing 11 a connection fitting 42. The tapping 41 serves to place on the casing 11 a connection fitting 43. Each of the connection connectors 42 and 43 comprises a threaded rigid ring 44 and a flexible tubing 45 whose one end is secured to the ring 44. The flexible tubing 45 is of the type used to replace artery sections. Here, the flexible tubing 45 is made of polyethylene terephthalate (PET) known as Dacron®. The establishment of the connection fitting 42 on the casing 11 is done by screwing the rigid ring 44 into the tapping 40 of the intake end 19. Similarly, the establishment of the connection connector 43 on the 11 is made by screwing the rigid ring 44 into the tapping 41 15 of the discharge end 21. When the pump 10 of Figure 2 is thus equipped with connection connectors in place respectively on the intake end and on the discharge end, there is a pumping unit 50 implantable on a patient. As further explained later, the pumping unit 50 is configured to be implanted in place of a portion of the patient's aorta removed between the heart and the first branches of the arterial blood circulation network. The distal end of the connector 42 (end opposite the ring 44) is provided to be sewn to the aorta on the heart side. The distal end of the connector 43 is intended to be sewn to the aorta on the side of the arterial blood circulation network. When the pumping unit 50 is implanted, the arterial blood leaving the heart, and more precisely the left ventricle of the heart, passes into the part 30 of the aorta located upstream of the removed section, into the fitting 42, into the pump. 10, in the connector 43 and in the part of the aorta located downstream of the removed section. 3004 1 1 1 11 The direction of blood flow in the connections 42 and 43 is shown by an arrow in FIG. 2. As can be seen in FIGS. 2 and 3, in the pump 10 of FIG. There are four similar spacers 14, with the same angular gap 5 between the neighboring struts. Each spacer 14 is here in the form of a helical band, which extends over the entire length of the cylindrical outer surface 51 of the stator 13. In addition to their function of mechanical connection between the casing 11 and the stator 13, the spacers 14 also fulfill here a hydraulic function linearization of the flow of blood passing in the space between the stator 13 and the envelope 11. In this space, under the effect of the drive by the turbine 16, in addition to the flow downstream, the blood tends to rotate around the stator 13. The spacers 14 oppose this tendency and therefore conform the flow of blood so that it flows in the axial direction. The rotor 12 has an upstream head 52 on the side of the intake end 19 (the side that is seen at the bottom) and a downstream head 53 on the side of the discharge end 21 (side that is seen in FIG. high). The shaft 17 extends between the upstream head 52 and the downstream head 53. The upstream head 52 has an annular apex 54 on either side of which extend respectively an upstream face 55 on the end of the end. admission 19 (side that is seen below) and a downstream face 56 on the side of the shaft 17 (side that is seen at the top). The upstream face 55 has a frustoconical surface 57 whose diameter decreases from the top 54 to the upstream end 58 of the rotor 12. From the surface 57 protrude the vanes 59, shown only in FIG. 4 to simplify the drawings. . The upstream face 55 forms the turbine 16, which is configured to drive the blood towards the casing 11 and towards the delivery opening 21.

The downstream face 56 has a frustoconical surface 60 whose diameter decreases from the top 54 to the shaft 17. The downstream head 53 has an annular apex 61 on each side of which extend respectively an upstream face 62 on the side of the shaft 17 (the side that is seen at the bottom) and a downstream face 63 on the side of the discharge end 21 (side that is seen at the top). The upstream face 62 has a frustoconical surface 64 whose diameter decreases from the top 61 to the shaft 17. The downstream face 63 has a frustoconical surface 65 whose diameter decreases from the vertex 61 to the end Downstream 66 of the rotor 12. The stator 13 has an inner surface 67 which is cylindrical, an upstream surface 68 disposed between the inner surface 67 and the outer surface 51 on the side of the inlet end 19 (side that can be seen bottom), and a downstream surface 69 disposed between the inner surface 67 and the outer surface 51 on the side of the discharge end 21 (side that is seen at the top). The upstream surface 68 and the downstream surface 69 are concave. They are frustoconical with a diameter that decreases between the outer surface 51 and the inner surface 67. In general, the stator 13 is shaped to occupy the space around the shaft 17 between the downstream face 56 of the upstream head 52 and the upstream face 62 of the downstream head 53. Thus, the diameter of the outer surface 51 of the stator 13 corresponds to the diameter of the top 54 of the upstream head 52 and to the diameter of the top 61 of the downstream head 53, the length of the outer surface 51 corresponds to the distance between the vertices 54 and 61, the diameter of the inner surface 67 of the stator 13 corresponds to the diameter of the outer surface 70 of the shaft 17, and the length of the inner surface 67 The stator 13 corresponds to the length of the outer surface 70 of the shaft 17. The spindle shape thus has the rotor-stator group is favorable to the hydraulic performance of the pump 10. In addition, the magnets 25 of electric motor located behind the outer surface 70 of the arb 17, the rotor 12 is provided behind the surface 60 of the downstream face 56 of the upstream head 52 of upstream magnets 71 of electromagnetic bearing and behind the surface 64 of the upstream face 62 of the downstream head 53 of downstream magnets 72 electromagnetic bearing. In addition to the electric motor windings 26 located behind the inner surface 67, the stator 13 comprises, behind the upstream surface 68, to the right of the magnets 71, upstream windings 73 of electromagnetic bearing and, behind the downstream surface 69, to the right of the magnets 72, downstream windings 74 of electromagnetic bearing. The magnets 71 and the windings 73 form on the upstream side of the rotor-stator group 15 an electromagnetic bearing serving to center the rotor 12 with respect to the stator 13 and to take up the axial forces exerted between the rotor 12 and the stator 13 in the upstream to downstream direction. The magnets 72 and the windings 74 form on the downstream side of the rotor-stator group 15 an electromagnetic bearing serving to center the rotor 12 with respect to the stator 13 and to take up the axial forces exerted between the rotor 12 and the stator 13 in the downstream to upstream direction. The ability to both center the rotor and regain the axial forces is provided by the inclined orientation of magnets 71 and windings 73 upstream and outward and by the inclined orientation of magnets 72 and windings. 74 downstream and outward. Figures 5 to 7 illustrate in the same way as Figures 2 to 4 a variant of the first practical embodiment of the pump according to the invention. In this variant, the casing 11 comprises electromagnetic bearing windings while the rotor-stator group 15, while keeping a general shape of spindle, is arranged differently. In this embodiment, the rotor 12 does not have a downstream head 53, the shaft 17 extending to the downstream end 66. For the rotor-stator group 15 to retain a spindle shape, the downstream surface concave 69 of the stator 13 is replaced by a convex downstream surface 80. The surface 80 is frustoconical with a slope corresponding to the slope of the surface 65 of the downstream face 63 of the downstream head 53.

Similarly, the shaft 17 has a portion 83 protruding beyond the downstream surface 80. The portion 83 is conical and in the extension of the downstream surface 80. The downstream magnets 72 are replaced by magnets 81 electromagnetic bearing located behind the surface 57 of the upstream face 55 of the upstream head 52. The downstream windings 74 are replaced by electromagnetic bearing windings 82 located behind the internal surface of the divergent portion 37 of the envelope 11. FIG. similar to that of Figures 5 to 7, except that the electromagnetic bearing formed by the magnets 81 and the windings 82 is replaced by a mechanical bearing formed by the upstream end 58 of the rotor 12 and by a bearing 85 on which supports the upstream end 58. The span 85 is secured to the casing 11 by arms 86.

FIG. 9 illustrates in the same way as FIG. 2 another variant of the first practical embodiment of the pump according to the invention. In this variant, the four struts 14 in the form of a helical band whose ends are offset by a quarter of a turn are replaced by two spacers 14 in the form of a helical band whose ends are offset by a half-turn. The implantation of the first practical embodiment of the pump 10, and more specifically the implantation of the pump unit 50 comprising this first practical embodiment of the pump, will now be described with reference to FIGS. 10 to 12. 10, the upstream connection connector 42 in place on the intake end 19 and the downstream connection connector 43 in place on the discharge end 21. FIG. 10 shows a human heart 90 and the arteries connecting to the core 90, in this case the pulmonary artery 91, the aorta 92 and the coronary arteries 93.

The heart 90 has a right ventricle which is used for the circulation of venous blood (blue blood) and a left ventricle which is used for the circulation of arterial blood (red blood).

Blood from the venous system enters the right ventricle and leaves it through the pulmonary artery 91, which carries venous blood to the lungs. At the exit of the lungs, the oxygenated blood returns to the heart by the pulmonary veins, arrives in the left ventricle and leaves it by the aorta 92 which takes the arterial blood towards the arterial system. Coronary arteries 93, which serve to irrigate the heart, are connected to the aorta 92 just as it leaves the heart 90. To simplify the drawings, the coronary arteries 93 are shown only in FIG. 10. At a certain distance from the heart 90, the aorta comprises the first ramifications of the arterial system, namely the supra-aortic trunks 94. The trunk closest to the heart is the brachiocephalic trunk 95. Between the coronary arteries 93 and the brachiocephalic trunk 95, the aorta 92 has a segment 96 without any branching. It is instead of a section of this segment that the first practical embodiment of the pump 10 will be implanted, and more specifically the pumping unit 50. To enable this implantation on a predetermined patient, the length of the pump 10 to be implanted is less than the length of the segment 96. In practice, the pump 10 has a length of less than 50 mm and more precisely between 35 and 50 mm. The flow rate of the pump 10 is in practice at least 5I / min, with the possibility of variation depending on the engine speed (up to 10 l / min). The segment 96 thus comprises an intermediate section 97 having a length similar to the length of the pump 10, a first section 98 situated between the coronary arteries 93 and the intermediate section 97, and a second section 99 situated between the intermediate section 97 and the Brachiocephalic trunk 95. To implant the pumping unit 50, the surgeon removes the intermediate section 97, as shown in Figure 11.

Subsequently, it secures the upstream connection fitting 42 to the first section 98 and secures the downstream connection connector 43 to the second section 99. For securing, the distal end of the connector 42 is sewn onto the first section 98 and the distal end of the connector 43 is sewn on the second section 99. Figure 12 shows the implanted pump unit 50. For the electrical supply and for the control of the pump 10, as seen in FIG. 13, the patient is provided with an external equipment comprising a battery 100 and an electronic control module 101 connected to the battery 100 here by a cable 102, and connected to the pump 10, here by a cable 103. FIG. 14 illustrates in the same way as FIG. 2 a variant of the first practical embodiment of the pump according to the invention, in which the casing 11 is externally provided with eyelets 105 for retaining threads. FIG. 15 shows in the same way as FIG. 12 this variant of the implanted pump as well as the sternum 106 of the patient and the retaining threads 107 placed by the surgeon, passing through the eyelets 105 and through the sternum 106.

It is also possible to attach eyelets to the sternum 106 and to pass the retaining son 107 in the hooks attached to the sternum. The retaining wires 107 improve the attachment of the pump unit 50 to the patient. In variants not shown, the casing 11 of the pump 10 shown in FIGS. 5, 8 and 9 is also provided with eyelets 105. The pump unit 50 illustrated in FIG. 16 similar to the pump unit 50 illustrated in FIG. 2, except that the upstream connection connector 42 is replaced by an upstream connection connector 46 and the downstream connection connector 43 is replaced by a downstream connection connector 47.

The connecting connectors 46 and 47 are similar to the connecting connectors 42 and 43, except that the distal end of the connectors 42 and 43 has a diameter D1 and that the distal end of the connectors 46 and 47 has a diameter D2 smaller. The pumping unit 50 illustrated in Fig. 16 is therefore suitable for a patient having a smaller aorta.

Fig. 17 shows an assembly 110 for providing a pumping unit 50 implantable on a predetermined patient having a corpulence within a predefined range of lumps. The assembly 110 comprises a pump 10 according to the first practical embodiment described above and four connection connectors 111, 112, 113 and 114. The connection connectors 111 and 112 are shaped like the connection connectors 42 and 43. The connection connectors 113 and 114 are shaped like the connecting connectors 46 and 47. To prepare a pumping unit 50 suitable for a predetermined patient, the diameter of the first section 98 and the diameter of the second segment 99 of its aorta are determined. for example by means of a scanner examination, and two connections among the connections 111 to 114 are respectively selected according to the diameter of the first section 98 to form the upstream connection connection, and as a function of the diameter of the second section 99 to form the connection downstream connection. In the example illustrated in FIG. 2, the connectors 111 and 112, both having a distal end of diameter D1, have been selected to form the upstream connector 42 and the downstream connector 43 of the pumping unit 50. As shown in Figure 16, the connectors 113 and 114, both having a distal end of diameter D2, have been selected to form the upstream connector 46 and the downstream connector 47 of the pump unit 50. The patients concerned have Indeed, the same diameter for the first section 98 and for the second section 99 of segment 96 of the aorta 92. In other patients, the diameter of the first section 98 and the diameter of the second section 99 are different.

In such a patient, the connection connector 113 on the upstream side and the connection connector 111 on the downstream side are taken to form the pumping unit 50. The assembly example 110 illustrated in FIG. 17, with four connectors two of which have the same diameter D1 and the other two the same smaller diameter D2 is suitable for a relatively narrow range of corpulences. For a larger body size range or for finer fitting to different body sizes, more fittings are provided with more diameter dimensions. In a variant that is not illustrated, the fastening between the connection connectors such as 42, 43, 46, 47 and 111 to 116 with the first practical embodiment of the pump 10 is different than by screwing, for example by snapping . FIG. 18 illustrates in the same way as FIG. 13 another way of implanting the first practical embodiment of the pump 10. Rather than being equipped with an upstream connection fitting such as the coupling 42 or the connection 46 and a downstream connection connector such as the connector 43 or the connector 47, the pump 10 according to the first practical embodiment 20 is equipped with an upstream connection duct 116 and a downstream connection duct 117 to form a pumping unit 118. The upstream connecting pipe 116 and the downstream connecting pipe 117 each have at one end a threaded rigid ring 119 similar to the rigid ring 44 of the connection fittings of the pumping assembly 50. At the other end, the upstream connection duct and the downstream connection duct comprise a nozzle 120 shaped to perform a lateroterminal connection. Between the rigid ring 119 and the nozzle 120, the duct 116 and the duct 117 comprise a tube 121. The ring 119 of the upstream connection duct 116 is put in place by screwing into the intake end 19 of the 11. The ring 119 of the downstream connection duct 117 is put in place by screwing into the delivery end 21. The end piece 120 of the upstream connection duct 116 is intended to be sewn on the left ventricular tip of the core 90, around an incision made in the wall of the left ventricular tip. The tip 120 of the downstream connection duct 117 is intended to be sewn on the segment 96 of the aorta 92, around an incision made in the wall of the aorta. When the assembly 110 is implanted as shown in FIG. 18, it provides a parallel derivation of the left ventricle. The blood is circulated in this bypass by the pump 10. A second practical embodiment of the pump 10, in which the casing 11 is formed by a perforated wall, will now be described with reference to FIGS. 19 and 20. 125 made of an elastic memory material and in which the connecting struts 14 are each formed by a perforated wall 126 made of an elastic shape memory material. The wall 125 and the walls 126 are of the type used to manufacture the arterial stents or the envelope of the percutaneous aortic valves. Here, wall 125 and walls 126 are made of nickel and titanium alloy known as Nitinol®. The casing 11 formed by the wall 125 and the spacers 14 each formed by a wall 126 are configured to take at the temperature of the human body, in the absence of external stresses, a nominal configuration according to FIG. nominal configuration of this second embodiment, the casing 11 is cylindrical. The rotor-stator group 15 is held by the spacers 14 centered vis-a-vis the casing 11 both radially and axially. As can be seen in FIG. 20, the pump 10 according to the second practical embodiment is intended to be implanted inside the segment 96 of the aorta 92 situated between the core and the first branches of the network. Arterial blood circulation.

The inlet end 19 is provided to be disposed on the side of the patient's heart. The discharge end 21 is provided to be disposed on the side of the arterial blood circulation network. The envelope 11 and the spacers 14, thanks to the fact that the material of the wall 125 and the walls 126 is elastic shape memory, are configured to collapse elastically towards the rotor-stator group 15 under the effect of radial compression. The rotor 12 and the stator 13 are permanently rigid and therefore do not deform under the effect of radial compression.

The rotor-stator group 15 is arranged like that of the pump 10 illustrated in FIGS. 2 and 3, except that the rotor 12 has a small diameter central bore 127 extending from the upstream end 58 to the Downstream end 66. In general, the rotor-stator group 15 of the pump 10 of the second practical embodiment has an outer diameter smaller than the rotor-stator group 15 of the first practical embodiment. In the nominal configuration illustrated in FIG. 19, the casing 11 has a diameter greater than the diameter of the segment 96 of the aorta 92 in which the pump 10 must be implanted.

Due to the elasticity of the material of the wall 125 and the walls 126, the pump 10 is compressed when it is implanted in the segment 96 of the aorta and thus exerts on it a radial force, which serves to immobilize the pump in the aorta. The gap between the rotor-stator group 15 and the envelope 11 and the wall of the aorta remains sufficient to allow good blood circulation. The rotor-stator group has for example a diameter of between 15 and 20 mm and the envelope 11 has for example a diameter of 60 mm in the nominal configuration (excluding external stress). Note that the segment 96 of the aorta has an average diameter of 30 mm, and is generally between 25 and 40 mm. Figure 21 shows an assembly 130 for implanting the pump 10 shown in Figures 19 and 20.

The assembly 130 includes a compression catheter 131 whose diameter is smaller than the diameter of the casing 11 in the nominal configuration and smaller than the diameter of the aortic segment 96 in which the pump 10 is to be implanted.

The pump 10 is arranged clamped in the compression catheter 131, in a configuration where the casing 11 and the struts 14 are collapsed on the rotor-stator group 15. In addition to the assembly 130 formed by the compression catheter 131 and by the pump 10 contained in the catheter 131, is used to implant the pump 10 a guide wire 132 and a transfer catheter 133 resting on one side of the pump 10, in this case the downstream side. The guidewire passes into the transfer catheter 133 and into the bore 127. The assembly 130 and the transfer catheter 133 can slide along the guidewire 132. To set up the pump 10, an incision 135 ( Figure 22) is performed in the patient's ribcage and an incision 136 on the segment 96 of the aorta 92. Then, the guide wire 132 is introduced through the incision 135 and the incision 136 to that the distal end is placed in the left ventricle of the heart 90, as shown in Fig. 22. The portion of the external guide wire 132 is passed to the patient in the bore 127 and in the transfer catheter 133 and pushing on the transfer catheter 133 to pass the portion of the assembly 130 containing the pump 10 inside the segment 96 of the aorta 92.

Figure 22 shows the assembly 130 passing through the incision 136. To simplify the drawing, the transfer catheter 133 is not shown in Figure 22 while only a portion of the restraining catheter 131 is illustrated. In practice, the compression catheter 131 and the transfer catheter 133 protrude from the patient's body out of the incision 135.

Then, the transfer catheter 133 is firmly held while the compression catheter 131 is pulled to extract it.

As the compression catheter 131 is extracted, the casing 11 and the struts 14 expand and abut against the wall of the aorta. Once the compression catheter 131 has been removed, the transfer catheter 133 and the guide wire 132 are removed. Figure 23 shows the implanted pump 10. For the power supply and for the control of the pump 10, the patient is provided with an external equipment including a battery 138 and an electronic control module 139 connected to the battery 138, here by a cable 140, and connected to the pump 10, here by a cable 141 set up at the same time as the pump 10. In a variant not shown, the wall 125 of the casing 11 and the walls 126 of the spacers 14 are coated with a flexible coating closing the openings . The flexible coating is for example polyethylene terephthalate (PET) known as Dacron®. In variants not shown, the pumps 10, rather than being powered and controlled by a cable such as 103 or 141, are powered and controlled by capacitive coupling through the skin of the patient. In non-illustrated variants of the pumps 10, the surfaces facing the rotor 12 and the stator 13, rather than being convex for the rotor 12 and concave for the stator 13, such as the surface 60 of the rotor 12 and the surface 68 of the stator 13 are concave for the rotor 12 and convex for the stator 13. In non-illustrated variants, the spacers of the pumps are shaped differently, for example with the pump 10 shown in FIGS. 8 which has the same spacers as the pump shown in Figure 9; and / or the number of spacers is different, for example a single spacer or more than four spacers. In variants not shown, the turbine 16 is arranged differently, with, for example, fewer or more blades 59 or with differently curved blades; the rotor 12 is shaped differently; and / or the rotor-stator group 15 is shaped differently, for example with a non-spindle shape. Many variations are possible depending on the circumstances, and it is recalled in this regard that the invention is not limited to the examples described and shown.

Claims (15)

REVENDICATIONS1. Left ventricular cardiac assist pump, having an inlet opening (18) and a delivery opening (20) aligned in an axial direction, said pump comprising: - a rotor (12) having a turbine (16) and a shaft (17) provided with magnets (25) of electric motor; and - a stator (13) disposed around said shaft (17), provided with stator windings (26) of an electric motor; characterized in that: - said pump comprises a casing (11) distinct from said stator (13) radially distant from said stator (13) and said turbine (16), with the rotor (12) and the stator (13) forming a rotor-stator group (15) surrounded by the casing (11), with at least one spacer (14) connecting the casing (11) and the stator (13); said casing (11) being tubular and delimiting said inlet opening (18) and said discharge opening (20) of the pump; and - the turbine (16) is configured to drive the blood to the casing (11) and to the discharge opening (20), whereby the blood circulates in said pump essentially between the casing (11) and the casing (11). rotor-stator group (15). 2. Pump according to claim 1, characterized in that the rotor-stator group (15) is generally spindle-shaped. 3. Pump according to any one of claims 1 or 2, characterized in that the rotor (12) comprises an upstream head (52) connected to the shaft (17) on the side of the inlet opening (18) said upstream head (52) having an annular apex (54) on either side of which extend respectively an upstream face (55) on the intake opening side (18) and a downstream face (56). on the side of the shaft (17), said upstream face (55) forming said turbine (16). 4. Pump according to claim 3, characterized in that the upstream face (55) of the upstream head (52) has blades (59) projecting from a surface (57) whose diameter decreases from the top (54). to the upstream end (58) of the rotor (12). 5. Pump according to any one of claims 3 or 4, characterized in that the downstream face (56) of the upstream head (52) has a surface (60) whose diameter decreases from the top (54) to to the shaft (17), the stator (13) having on the side of the inlet opening (18) an upstream surface (68) inclined as the surface (60) of the downstream face (56) of the upstream head (52), having behind the surface (60) of the downstream face (56) of the upstream head (52) of the upstream magnets (71) of electromagnetic bearing and behind the upstream surface (68) of the stator (13) windings upstream (73) to overcome electromagnetic. 6. Pump according to any one of claims 3 to 5, characterized in that the rotor (12) comprises a downstream head (53) connected to the shaft (17) on the side of the discharge opening (20), said downstream head (53) having an annular apex (61) on either side of which extend respectively an upstream face (62) on the side of the shaft (17) and a downstream face (63) on the side of the discharge opening (20), the upstream face having a surface (64) whose diameter decreases from the top (61) to the shaft (17), the stator (13) having on the opening side discharge device (20) a downstream surface (69) inclined as the surface (64) of the upstream face (62) of the downstream head (53), with behind the surface (64) of the upstream face (62) of the head downstream (53) of the electromagnetic gain bottom magnets (72) and behind the downstream surface (69) of the stator (13) of the electromagnetic bearing downstream windings (74). 7. Pump according to any one of claims 3 to 5, characterized in that the upstream face (55) of the upstream head (52) has a surface (57) whose diameter decreases from the annular apex (54) to at the upstream end (58) of the rotor (12), the casing (11) having a diverging portion (37) opposite the upstream face (55) of the upstream head (52) with behind the surface (57); ) of the upstream face (55) of the upstream head (52) electromagnetic bearing magnets (81) and behind the inner surface of thedivergente portion (37) of the envelope (11) of the electromagnetic bearing windings (82). 8. Pump according to any one of claims 3 to 5, characterized in that the upstream face (55) of the upstream head (52) has a surface (57) whose diameter decreases from the annular apex (54) to at the upstream end (58) of the rotor (12), said pump (10) having a bearing surface (85) on which the upstream end (58) of the rotor (12) bears, said bearing (85) being secured to the casing (11) by arms (86). 9. Pump according to any one of claims 1 to 8, characterized in that said casing (11) is formed by a solid wall (35) with permanent rigidity and each said connecting strut (14) is formed by a solid wall. (36) permanently rigid. 10. Pump according to claim 9, characterized in that said casing (11) comprises a divergent portion (37), a straight portion (38) and a convergent portion (39), with the straight portion (38) extending between the diverging portion (37) and the converging portion (39), the diverging portion (37) extending from an inlet end (19) defining said inlet opening (18) to said straight portion, and the convergent portion (39) extending from the straight portion (38) to a discharge end (21) defining said discharge opening (20). 11. Pump according to any one of claims 9 or 10, characterized in that said casing (11) is externally provided with eyelets (105) for retaining son (107). 12. Pump according to any one of claims 1 to 6, characterized in that said casing (11) is formed by a wall (125) made of an elastic shape memory material and each said connecting strut (14) is formed by a wall (126) made of an elastic shape memory material. 13. Pump according to claim 12, characterized in that the rotor (12) has a bore (127) extending from an upstream end (58) to a downstream end (66). 14. Pump according to any one of claims 1 to 13, characterized in that an electric cable (31) runs along said spacer (14). 15. Pump according to any one of claims 1 to 14, characterized in that each said connecting strut (14) is helical and extends along said stator (13).