BIDIRECTIONAL ARTERIAL CANNULA FOR EXTRACORPOREAL MEMBRANE OXYGENATION AND METHOD FOR USING SUCH A CANNULA

Abstract

An arterial cannula for ECMO includes a main arterial cannula with an inner wall and having a first end with a blood outflow port. The first end is intended to be introduced into an artery so as to inject the blood retrogradely into the artery. A retro-perfusion cannula is configured to be translatably movable between a retracted position in the first end of the main arterial cannula and a deployed position at least partly outside the main arterial cannula and opposite the blood outflow port of the main arterial cannula.

Claims

1. An arterial cannula for ECMO comprising: a main arterial cannula including an inner wall and having a first end with a blood outlet orifice, the first end being intended to be inserted into an artery in order to inject blood in a retrograde manner into the artery, and a retroperfusion cannula configured to be movable in translation between a retracted position in the first end of the main arterial cannula and a position at least partially deployed out of the first end of the main arterial cannula, the retroperfusion cannula being opposite to the blood outlet orifice of the main arterial cannula, wherein the retroperfusion cannula comprises a tube with a diameter smaller than a diameter of the main arterial cannula, and a ring with a diameter substantially identical to the diameter of the main arterial cannula, the ring being disposed at a proximal end of the retroperfusion cannula with respect to the blood outlet orifice of the main arterial cannula.

2. The arterial cannula according to claim 1, having an L-shape, the arterial cannula comprising a first branch corresponding to the first end intended to be introduced into the artery, and a second branch intended to cooperate with an oxygenator, the first branch and the second branch being connected by an elbow.

3. The arterial cannula according to claim 1, wherein the retroperfusion cannula is configured to slip in translation in contact with the inner wall of the main arterial cannula, until the ring comes into contact with a stop of the inner wall.

4. The arterial cannula according to claim 1, wherein a cutout is present between the tube and the ring.

5. The arterial cannula according to claim 1, wherein the tube has an elliptical profile.

6. The arterial cannula according to claim 1, wherein the ring has a convex internal wall.

7. The arterial cannula according to claim 1, wherein the inner wall of the main arterial cannula has comprises a longitudinal groove, and the ring of the retroperfusion cannula comprises a rib, the longitudinal groove cooperating with the rib.

8. The arterial cannula according to claim 1, wherein the main arterial cannula comprises a translation portion of the ring, the translation portion of the ring having an inner diameter larger than an inner diameter of a non-translation portion of the main arterial cannula.

9. The arterial cannula according to claim 2, wherein the tube has a beveled distal end, opposite to the ring, to be adapted to a curvature of the elbow of the main arterial cannula when the retroperfusion cannula is in the retracted position, the tube including an opening directed towards the second branch of the main arterial cannula.

10. An introducer stylet configured to be inserted into an arterial cannula according to claim 1, in order to enable both an insertion of the main arterial cannula into an artery and a deployment of the retroperfusion cannula out of the main arterial cannula, the introducer stylet being configured to obstruct the main arterial cannula.

11. The introducer stylet according to claim 10, including a proximal end configured to be disposed in the first end of the main arterial cannula, the proximal end having a diameter increasing up to a diameter substantially identical to the diameter of the main arterial cannula, the proximal end being followed by a first intermediate portion with a length at least larger than a length of the retroperfusion cannula and a diameter smaller than the diameter of the main arterial cannula, the first intermediate portion being followed by a second intermediate portion with a diameter substantially identical to the diameter of the main arterial cannula.

12. The introducer stylet according to claim 10, having a shape complementary to the main arterial cannula with the retroperfusion cannula in the retracted position.

13. A removal stylet configured to be inserted into an arterial cannula according to claim 1, in order to allow retracting the retroperfusion cannula in the main arterial cannula, and to allow removing the main arterial cannula out of the artery, the removal stylet being configured to obstruct the main arterial cannula.

14. The removal stylet according to claim 13, comprising a bulge configured to cooperate with the ring of the retroperfusion cannula in order to drive the retroperfusion cannula in translation in the main arterial cannula, when the removal stylet is inserted into the main arterial cannula.

15. A kit comprising an arterial cannula according to claim 1, further including an introducer stylet configured to be inserted into the arterial cannula to enable both an insertion of the main arterial cannula into an artery and a deployment of the retroperfusion cannula out of the main arterial cannula, the introducer stylet being configured to obstruct the main arterial cannula, and a removal stylet configured to be inserted into the arterial cannula to allow retracting the retroperfusion cannula in the main arterial cannula, and to allow removing the main arterial cannula out of the artery, the removal stylet being configured to obstruct the main arterial cannula.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0050] FIG. 1 is a schematic view of a main arterial cannula and a retroperfusion cannula according to the prior art.

[0051] FIG. 2 represents an arterial cannula for ECMO according to the present disclosure, in longitudinal section.

[0052] FIG. 3 is a schematic view in longitudinal section of a portion of the arterial cannula of FIG. 2.

[0053] FIG. 4 is a schematic perspective view of a retroperfusion cannula of the arterial cannula of FIG. 2.

[0054] FIG. 5 is a detail view of FIG. 3, illustrating the alignment between the retroperfusion cannula and the main arterial cannula when the retroperfusion cannula is in the deployed position.

[0055] FIG. 6 is a schematic cross-sectional view of the arterial cannula comprising a retroperfusion cannula.

[0056] FIG. 7 is a schematic perspective view of an introducer stylet according to a first embodiment.

[0057] FIG. 8 is a schematic perspective view of a detail of the introducer stylet of FIG. 7.

[0058] FIG. 9 is a schematic sectional view of the introducer stylet of FIG. 8, inserted into the ring of the retroperfusion cannula according to the present disclosure.

[0059] FIG. 10 is a schematic longitudinal sectional view of an arterial cannula portion provided with an introducer stylet according to FIG. 7.

[0060] FIG. 11 is another schematic longitudinal sectional view of the arterial cannula, illustrating an embodiment in which the main arterial cannula has a difference in inner diameter of FIG. 10.

[0061] FIG. 12 is a partial schematic view of an introducer stylet according to a second embodiment.

[0062] FIG. 13 is a schematic view of the introducer stylet of FIG. 9 inserted into a retroperfusion cannula of an arterial cannula according to the present disclosure.

[0063] FIG. 14 is a partial schematic view of the arterial cannula according to the present disclosure, provided with a removal stylet inserted into the main cannula.

[0064] FIG. 15 is a schematic longitudinal sectional view of a portion of the arterial cannula of FIG. 14, detailing the removal stylet.

[0065] FIG. 16 is a schematic perspective view of the removal stylet of FIGS. 14 and 15.

[0066] FIG. 17 is a schematic perspective view of a portion of the arterial cannula of FIG. 2, including a retroperfusion cannula according to one variant.

[0067] FIG. 18 is a schematic perspective view of a portion of the retroperfusion cannula illustrated in FIG. 17.

DETAILED DESCRIPTION OF THE DRAWINGS

[0068] FIG. 1 has been described before.

[0069] FIG. 2 illustrates an arterial cannula 20 according to the present disclosure.

[0070] The arterial cannula 20 has a main arterial cannula 22 having a first end 24 comprising a blood outlet orifice 26, and a second end 28 intended to be connected to an oxygenator (not represented).

[0071] The main arterial cannula 22 may have an L-like shape, a first branch of which 25 comprises the first end 24, and a second branch 25′ comprises the second end 28. The first 25 and second 25′ branches may be connected by an elbow 27 which could have an angle of curvature of 135° on average and which could vary from 90° to 150°.

[0072] The first end 24 is configured to be introduced into an artery (not represented) in order to inject the blood in a retrograde manner according to the arrow F, into the artery. It includes a retroperfusion cannula 30 configured to be movable in translation between a retracted position (FIG. 6) in the first end 24 of the main arterial cannula 22 and a deployed position (FIG. 2) in the artery, partially out of the main arterial cannula 22, opposite to the blood outlet orifice 26 of the main arterial cannula 22. The retroperfusion cannula 30 is intended to inject blood into the artery in an anterograde manner, according to the arrow A.

[0073] The first end 24 of the main arterial cannula 22, as well as the retroperfusion cannula 30, may be rectilinear.

[0074] The main arterial cannula 22 may include, at its end proximal to the blood outlet orifice 26, a hole 29 allowing the blood to be evacuated in the event of an obstruction of the outlet orifice 26.

[0075] The main arterial cannula 22 may be formed primarily of nitinol or braided steel overmolded with silicone or polyurethane. It may have a portion in contact with the retroperfusion cannula 30 in the retracted position, made of polycarbonate. Thus, it may have a flexible portion made of nitinol or steel, and a rigid portion made of polycarbonate.

[0076] The retroperfusion cannula comprises a proximal end 35 with respect to the blood outlet orifice 26 of the main arterial cannula, and an opposite distal end 35′.

[0077] As illustrated in more detail in FIGS. 3 to 6, the retroperfusion cannula 30 may comprise a tube 32 such as an elliptical tube, having for example a surface of 3.15 mm2, a height “h” of 1 2 mm, a width L of 3.34 mm and a length “I” in the range of 5 to 15 mm. The retroperfusion cannula 30 may also comprise a ring 34 such as a circular ring. The ring 34 can be metallic or made of polyurethane. It may have a diameter D very slightly smaller than the inner diameter D′ of the main arterial cannula allowing the retroperfusion cannula to slip without difficulty in the main arterial cannula. The tube 32 may comprise a proximal end 36 with respect to the blood outlet orifice 26 of the main arterial cannula 22, and an opposite so-called distal end 36′. The ring 34 may be disposed at the proximal end 35 of the retroperfusion cannula 30. It may be separated from the tube 32 by a cutout 38. The proximal 36 and distal 36′ ends of the tube 32 may be oblique, that is to say beveled.

[0078] The beveled distal end 36′ may be adapted to the curvature of the elbow 27 of the main arterial cannula when the retroperfusion cannula 30 is in the retracted position. Thus, in the retracted position, the distal end 36′ of the tube 32 is complementary to the elbow 27. It does not project from the elbow 27, neither from inside nor from outside thereof, which allows for an easy slip of the arterial cannula out of the artery upon removal thereof. The beveled distal end 36′ forms a blood passage orifice configured to direct blood opposite to the second branch 25′ of the main arterial cannula 22.

[0079] As shown in FIGS. 17 and 18, the tube 32 may include an opening 39 directed towards the second branch 25′ of the main arterial cannula 22. The opening may be disposed at the distal end 36′ of the tube 32.

[0080] The beveled distal end 36′ may have a wall 37 including a first face 37A with a length larger than an opposite second face 37B, the first face 37A comprising the opening 39 directed towards the second branch 25′ of the main arterial cannula 22. The opening allows ensuring that blood could flow through the tube, even when the beveled distal end is obstructed. Indeed, the beveled distal end could be obstructed for example by the artery.

[0081] The beveled proximal end 36 of the tube 32 may be arranged proximate to the cutout 38. It may be adapted to the curvature of the elbow 27 of the main arterial cannula 22 when the retroperfusion cannula 30 is in the deployed position. Thus, in the deployed position, the proximal end 36 of the tube is complementary to the elbow and does not project from inside the elbow, which allows for an easy circulation of blood in the main arterial cannula.

[0082] The main arterial cannula 22 may have a translation portion T (FIG. 11) of the ring 34 with a length identical to the length “I” of the tube 32. The translation portion T may be arranged at the first end 24 of the main arterial cannula 22.

[0083] The ratio between the inner diameter D′ of the main arterial cannula and the inner diameter of the tube 32 of the retroperfusion cannula 30 may be 8.

[0084] The retroperfusion cannula 30 may have a wall having a thickness “e” of 0.1 mm.

[0085] An aperture 26′ (FIG. 3), such as an elliptical lumen, may be present in the elbow 27 of the main arterial cannula 22, opposite to the blood outlet orifice 26, to enable the retroperfusion cannula 30 to be deployed out of the main arterial cannula 22. The aperture 26′ may have a shape and dimensions identical to the shape and dimensions of the cross-section of the tube 32. Thus, only tube 32 is able to be deployed in the artery through the aperture 26′.

[0086] FIG. 3 further shows that the first end 24 of the main arterial cannula 22 may have an inner wall 31 in contact with which the tube 32 and the ring 34 of the retroperfusion cannula are configured to slip. Thus, the tube 32 could be disposed in contact with the inner wall 31.

[0087] Furthermore, the tube 32 of the retroperfusion cannula 30 may have a bulge 33, for example flexible, configured to block the retroperfusion cannula 30 in the deployed position. The bulge 33 may be disposed on an upper portion 32′ of the tube 32. The bulge 33 may be directed towards the second end 28 of the main arterial cannula 22. It could cooperate with the aperture 26′ of the elbow 27. More specifically, it could cooperate with an outer and upper portion of the aperture 26′ of the elbow 27 of the main arterial cannula 22. The bulge 33 allows preventing a spontaneous removal of the retroperfusion cannula 30 in the main arterial cannula.

[0088] The tube 32 may be made of a biocompatible composite material. It may include a portion at the cutout 38 in the form of a steel strip.

[0089] Furthermore, as shown in FIG. 4, ring 34 may include a rib 52 configured to cooperate with a groove 50 (FIG. 6) disposed longitudinally in the inner wall 31 of the main arterial cannula 22. The groove 50 may have a length corresponding to the translation length of the retroperfusion cannula 30. Thus, the groove 50 allows limiting and containing the translation of the retro cannula. It allows preventing the retroperfusion cannula 30 from escaping from the first end 24 of the main arterial cannula 22 upon switching from the retracted position into the deployed position, so that the proximal end 36 of the tube 32 stops exactly in the thickness of the wall of the elbow 27 of the main arterial cannula 22 in the deployed position. Furthermore, it allows limiting the translation of the retroperfusion cannula 30 upon switching from the deployed position into the retracted position, such that the distal end 36′ of the tube 32 stops exactly within the thickness of the wall of the elbow 27 of the main arterial cannula 22 in the retracted position.

[0090] In one embodiment represented in FIG. 13, the ring 34 does not includes any rib 52 and the inner wall 31 of the main cannula does not have any groove 50. In this embodiment, the main arterial cannula has, outside the translation portion T of the ring 34, an inner diameter smaller than the diameter D of the ring 34 (FIG. 11). Thus, the translation portion T having an inner diameter larger than the inner diameter of the rest of the main arterial cannula, the inner diameter of the translation portion T being very slightly larger than the diameter D of the ring. The translation of the ring is limited upon deployment and/or removal of the retroperfusion cannula by the smaller inner diameter of the main arterial cannula outside the translation portion T of the ring. The difference in diameter forms a stop 21 (FIG. 11) at each end of the translation portion T.

[0091] As shown in FIG. 3, the main arterial cannula may have an inner protrusion 51. As will be seen later on, the inner protrusion 51 is configured to limit the translation of an introducer stylet 40 intended to be inserted into the arterial cannula 20.

[0092] FIGS. 7 to 11 illustrate a first embodiment of an introducer stylet 40 according to the present disclosure. The introducer stylet is configured to be inserted into an arterial cannula 20 as previously described, before introduction thereof into an artery, in order to enable both the insertion of the main arterial cannula 22 into the artery and the deployment of the retroperfusion cannula 30 out of the main arterial cannula 22. It may have a proximal end 42 in the form of a point, intended to pass through the blood outlet orifice 26 of the main arterial cannula 22, when the introducer stylet 40 is inserted into the arterial cannula, in order to facilitate the introduction of the main arterial cannula 22 into the artery. It may further have a distal end 42′ in the form of a clamp, configured to clasp the second end 28 of the arterial cannula.

[0093] As shown in FIG. 7, the introducer stylet 40 may advantageously have a first intermediate portion 47, proximal to the proximal end 42, and a second intermediate portion 47′, proximal to the distal end 42′ in the form of a clamp. The first intermediate portion 47 may have a length slightly larger than that of the retroperfusion cannula. It may have a diameter smaller than the diameter of the main arterial cannula. Thus, the first intermediate portion 47 does not spatially interfere with the retroperfusion cannula when the latter is in the retracted position in the main arterial cannula. On the other hand, the second intermediate portion 47′ may have a diameter substantially identical to that of the main arterial cannula in order to have a minimum clearance upon introduction thereof into the arterial cannula. Furthermore, this allows conferring some rigidity on the introducer stylet and enabling an axial and centered progression upon insertion of the introducer stylet into the arterial cannula. However, in order to be non-obstructive, the second intermediate portion 47′ may have longitudinal grooves (not represented) enabling blood to circulate.

[0094] The proximal end 42 of the introducer stylet 40 may have an increasing diameter, up to a maximum diameter D″ identical to the inner diameter D′ of the main arterial cannula 22, which allows obstructing the main arterial cannula 22. Thus, no blood flow circulates as long as the introducer stylet is disposed in the main arterial cannula. This increasing diameter enables the introducer stylet 40 to be inserted into the first end 24 of the main arterial cannula 20 in which the retroperfusion cannula 30 is disposed in the retracted position. Indeed, the retroperfusion cannula 30 in the retracted position reduces the free inner space of the main arterial cannula (as shown in FIG. 6).

[0095] Furthermore, the proximal end 42 of the introducer stylet 40 may be configured to cooperate with the ring 34 of the retroperfusion cannula. To this end, the proximal end 42 may include a groove 44 in which the ring 34 is intended to fit (FIG. 10). The groove 44 allows holding the retroperfusion cannula 30 in the retracted position in the main arterial cannula 22 upon insertion of the main arterial cannula 22 into an artery, and to drive the retroperfusion cannula 30 in its deployed position upon removal of introducer stylet 40 from arterial cannula 20.

[0096] The proximal end 42 of the introducer stylet 40 may be configured to abut against the inner protrusion 51 (FIG. 3) of the main arterial cannula, at the maximum diameter D″. Thus, the translation of the introducer stylet 40 in the main arterial cannula is limited so that the ring 34 of the retroperfusion cannula fits into the groove 44 of the introducer stylet.

[0097] FIG. 8 shows that the insertion stylet 40 may have incisions 45 at and around the groove 44. These incisions allow forming a deformable retentive system 49. Thus, when the retroperfusion cannula completes its translation in the main arterial cannula upon deployment thereof, the diameter of the stylet at the deformable retentive system retracts slightly enabling it to slip out of the ring to completely free itself from the arterial cannula.

[0098] The introducer stylet 40 may be deformable, in order to be able to confer any shape on the main arterial cannula 22. Indeed, the flexible portions of the main arterial cannula 22 are able to be deformed by the introducer stylet 40, so as to impart thereon, for example, a Z-like shape comprising a first free branch corresponding at the first end 24 intended to be introduced into an artery, a central branch and a second free branch intended to cooperate with the oxygenator (not represented).

[0099] As shown in FIG. 9, the introducer stylet 40 may be axially perforated at its center into a hollow cylinder 400.

[0100] FIGS. 12 and 13 illustrate a second embodiment of an introducer stylet 40′ according to the present disclosure.

[0101] The introducer stylet 40′ may have a recess 46 complementary to the tube 32 of the retroperfusion cannula 30 (FIG. 10), enabling the introducer stylet 40′ to be introduced into the first end 24 of the main arterial cannula 20 in which the retroperfusion cannula 30 is disposed in the retracted position. This recess 46 may include a lug 48 configured to cooperate with the tube 32 of the retroperfusion cannula 30 in order to enable the deployment thereof out of the main arterial cannula 22.

[0102] The introducer stylet 40 according to the first embodiment is symmetrical with respect to its longitudinal axis and is therefore configured to be introduced into the arterial cannula 20 in any position irrespective of the rotation of the stylet on its axis.

[0103] On the other hand, the introducer stylet 40′ according to the second embodiment is configured to be introduced into the arterial cannula in an accurate position, so that the recess 46 cooperates with the tube 32 of the retroperfusion cannula 30.

[0104] These stylets 40, 40′ enable a bidirectional translation of the retroperfusion cannula.

[0105] FIGS. 14-16 illustrate a removal stylet 53 configured to allow retracting the retroperfusion cannula 30 in the main arterial cannula 22, in order to allow retracting the main arterial cannula 22 out of an artery.

[0106] The removal stylet 53 is configured to be inserted into an arterial cannula 20 as previously described, when the retroperfusion cannula 30 is in the deployed position, in order to allow retracting the retroperfusion cannula 30 in the main arterial cannula 22. It may have a bulge 54 configured to cooperate with the ring 34 of the retroperfusion cannula 30 in order to drive it in translation in the main arterial cannula 22, when the removal stylet 53 is inserted into the main arterial cannula 22. The bulge 54 may be disposed at a so-called proximal end of the removal stylet 53. The proximal end of the removal stylet 53 is an end intended to be disposed proximate to the blood outlet orifice 26 of the main arterial cannula 22, when the removal stylet 53 is inserted into the arterial cannula 20. The bulge 54 may be intended to fit into the ring 34. It could obstruct the ring 34. The bulge 54 may be spherical. The removal stylet 53 may also have a first intermediate portion 54′, preferably cylindrical, whose diameter enables the removal of the retroperfusion cannula without spatial interference therewith upon retraction thereof in the main arterial cannula. This first intermediate portion 54′ may have a length identical to that of the retroperfusion cannula. The removal stylet may also have a second intermediate portion 54″, preferably cylindrical, whose diameter is equal to that of the main arterial cannula in order to obstruct it to prevent the rise of blood in the main arterial cannula. Moreover, the removal stylet may have a distal end 54″ in the form of a cap, configured to cooperate with the second end 28 of the arterial cannula.

[0107] The second intermediate portion 54″ of the removal stylet 53 may have a diameter identical to the inner diameter D′ of the main arterial cannula 22, which allows obstructing the main arterial cannula 22. Thus, no blood flow circulates in the arterial cannula when the removal stylet is disposed in the main arterial cannula.

[0108] The bulge 54 is configured to cooperate with the ring 34 which may have a convex inner wall 34′ (FIG. 5) in order to drive the retroperfusion cannula 30 in translation in the main arterial cannula 22, upon insertion thereof into the arterial cannula 20.

[0109] Furthermore, the convex internal wall 34′ of the ring 34 allows laminating the blood flow and thus avoiding hemolysis and turbulent blood flows.

[0110] As shown in FIG. 14, the removal stylet 53 allows obstructing the main arterial cannula 22 when inserted into the main arterial cannula.