Rotor for blood pump

Abstract

A radially compressible and expandable rotor for a blood pump may include a rotor with at least one impeller blade having a flexible blade body. The at least one impeller blade includes an elastically deformable first material supported by a relatively stiff second material of a structural frame encapsulated within the blade body. The relatively stiff second material of the structural frame may be adapted to provide a support structure for the impeller blade body. The structural frame has a predetermined expanded shape when expanded. The second material of the structural frame may have a shape with symmetry along a longitudinal axis defined by the rotor.

Description

[Technical field]

[0001] The present invention relates to a wire frame in a folding impeller for a blood pump, and more particularly to a radially compressible and expandable rotor having an impeller with a structural frame encapsulated within the impeller body. [Background technology]

[0002] In the following description, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of some exemplary embodiments. However, it will be apparent to one skilled in the art that the present subject matter may be practiced without these specific details or with slight variations.

[0003] Mechanical circulatory support has become the standard of practice for the treatment of late-stage heart failure. The most common method of providing mechanical circulatory support is the left ventricular assist device ("LVAD"), which is a pump that performs most, if not all, of the left ventricle's functions. LVADs are larger devices that can be placed via surgical implantation techniques for long-term support. In contrast, intracardiac blood pumps are smaller devices that can be implanted in the heart without major surgery via catheters delivered through the arterial / venous system. Such devices are often referred to as "percutaneous pumps" or "catheter pumps."

[0004] The percutaneous pump housing must have a relatively small diameter to allow positioning through the patient's vasculature, typically less than about 7 mm in diameter. Percutaneous pumps designed to support a failing left ventricle generally provide a blood flow output of about 4.5 L / min for pressures of 60-80 mmHg (8000-10666 Pa), although lower flow rates may be acceptable for partial support.

[0005] Percutaneous pumps are typically designed to be stationary or positioned so that they are located within or across the aortic valve during use. Therefore, these pumps can be made very small and can also be compressed for transport and expanded for operation. This particular application of such pumps in the medical field relates to invasive blood pumps that can be delivered inside a patient's body in a radially compressed state and can expand there upon actuation to pump blood.

[0006] US Patent No. 5,399,633 discloses a rotor with several blades, which are manufactured integrally with the hub and can be folded on the hub in a compressed state due to the material elasticity of the blades in order to radially compress the rotor. During operation, the blades stand up spontaneously. The material of the rotor must be carefully selected for its elastic and deformation properties, but it has long been felt that there is a delicate balance between the impeller being flexible to fold and being able to exert sufficient force on the liquid or blood being transported during operation.

[0007] Another radially compressible and expandable rotor for a blood pump with impeller blades is known from US Pat. No. 5,399,633, which has a support structure without any closed edge structure or edge curve, and the stiffening struts are at least partially embedded in the material of the impeller blade body, and the stiffening struts have a stiffening curvature, preferably in an area radially close to the hub.

[0008] Similar pumps are known from US Pat. No. 5,399,623 and US Pat. No. 5,499,633, which disclose radially compressible and expandable rotors for pumps with stiffening struts at least partially embedded in the material of the impeller blade body, the thickness of the impeller blade between the pressure side and the suction side being at least 80% of the thickness of at least one strut in the same direction.

[0009] Any discussion of prior art throughout this specification should in no way be deemed an admission that such prior art is widely known or forms part of the common general knowledge in the art.The present invention relates to a wire frame in a folding impeller for a blood pump, and more particularly to a radially compressible and expandable rotor having an impeller with a structural frame encapsulated within the impeller body. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] U.S. Patent No. 7,393,181 [Patent Document 2] U.S. Pat. No. 1,092,0596 [Patent Document 3] US Patent Application Publication No. 2008 / 0114339 [Patent Document 4] U.S. Patent No. 9,611,743 Summary of the Invention

[0011] The inventors have recognized that, among other things, a problem to be solved may include locating and deploying a percutaneous device within a patient's vasculature to support blood flow within the patient. The present subject matter may help provide a solution to this problem, such as an expandable and foldable impeller with an embedded structural frame, such as configured for use in a percutaneous blood pump.

[0012] It may be advantageous to provide a radially compressible and expandable rotor for a blood pump having impeller blades with a structural frame encapsulated by a flexible impeller blade body to provide functional support and shape during operation.

[0013] It may be advantageous to provide a structural frame having a skeletal shape selected from the group of honeycomb cells, diamond cells, rectangular cells, tombows, wavy strut wings, diagonal strut wings, which may provide uniform support to the flexible impeller blade body.

[0014] It would be advantageous to provide a device that assists blood flow from the left ventricle to the aorta of the heart, where blood is ejected from the device in the left ventricle towards the atrioventricular valve. In order to keep the size of the device as small as possible and also to reduce the risk of snagging when inserting and moving the device to a desired location through the tortuous anatomy of the heart, it may be advantageous to provide a device with a collapsible impeller and collapsible impeller cage. The collapsible configuration of the pump and impeller allows for easier insertion or implantation of the device via the femoral artery, reducing the need for a sternotomy.

[0015] It may be advantageous to provide the collapsible impeller and collapsible impeller cage with a shape memory metal so that the impeller and impeller cage operate by retaining their functional shape when expanded in a desired location.

[0016] It can be advantageous to provide a structural frame with a honeycomb pattern to resist stretching and compression in the helical plane in which it is oriented. When that plane follows the helical shape, compound curves can be created. These compound curves with planar stability become very resistant to deformation of the entire structure. At the same time, voids in the plane allow temporary force to overcome the heat set structure. The polymer movement required to crush the impeller blades is also facilitated by the cellular nature and regularity of the honeycomb structure.

[0017] It may be advantageous to provide a structural frame with a diamond pattern so as to have an economical way of forming planar shapes with less material. A diamond structure in a plane may have different resistance to stretching and compression along different axes. Advantages of having a structural frame with a diamond pattern with an orientation in a helical plane to utilize compressibility or expandability when needed to assist in the collapse of impeller blades such as helical planar impeller blades. Long struts made up of multiple edges of individual diamonds can be utilized to generate strength by directly spanning longer distances for a given application, a property that is difficult to utilize with a honeycomb pattern. The movement of polymer required to collapse the impeller blades may also be facilitated by the cellular nature and regularity of the diamond structure.

[0018] It may be advantageous to have less metal at the trailing edge, and the metal frame may taper away from the trailing edge, so that it folds or collapses more easily as the sheath advances from the trailing edge. Once the trailing edge begins to collapse, the rest of the rotor and impeller body can also fold easily.

[0019] It may be advantageous to provide a structural frame that is included to allow the impeller blades to not deform too much during use and when pressure is acting to bend the impeller.

[0020] It may be advantageous to provide a blood pump that is placed in the left ventricle and delivered via the vascular system, which is implantable and typically does not require surgery. For this reason, the blood pump is used during high-risk coronary interventions (such as stent replacement) when the heart may stop providing flow and the blood pump is urgently needed to provide cardiac support during the procedure. It may be an additional advantage to provide the blood pump to be used for patients experiencing cardiogenic shock, which is when the patient suffers from severe heart failure and is in a life-threatening condition.

[0021] It may be advantageous to allow the impeller blades to deform less during use and when pressure is acting to bend the rotor. The metal frame may act to counter this, so the impeller blades can maintain their shape, thus improving hydraulic (hemodynamic) performance and minimizing blood damage (hemolysis).

[0022] It may be advantageous to provide a metal frame, preferably laser cut from a flat sheet of superelastic Nitinol, to allow it to be tightly folded to a small diameter and then return to the design shape when the sheath is removed. The frame can then be "heat set" into the desired shape before a polymer is added to encapsulate the frame.

[0023] It may be advantageous to allow the polymer encapsulating the frame to mechanically lock to all of the "elements" of the frame ("diamonds", "honeycomb", etc.), which may ensure good adhesion to the frame and prevent separation or delamination that may otherwise be problematic.

[0024] It may be advantageous to provide a wire frame that can be made thin (approximately 0.13 mm) and that can be electropolished to round the edges, preventing the frame from "cutting" the polymer.

[0025] It may be advantageous to provide a technique that may allow injection molding as well as casting or vacuum casting. In one example, the first material, such as an elastically deformable material, may include a polymer. The polymer material is preferably a polyurethane with known hemocompatibility, such as a material from Lubrizol (Wickliffe, Ohio) sold under the trademark PELLETHANE®, or another material from Lubrizol (Wickliffe, Ohio) sold under the trademark TECOFLEX®, but may also be silicone or other hemocompatible polymers.

[0026] It may be advantageous to provide various methods of joining the wire frame to the rotor or shaft, for example a rotor cross section that wraps around the rotor or shaft, or a rotor with wire frame locking means, or the wire frame welded to the rotor.

[0027] It may be advantageous to provide a denser wire frame or more wire frame close to the leading edge where the pressure on the impeller blades is greater, because the impeller body will be conditioned by the wire frame to provide the most support where it is needed and less support where it is not, thus allowing those sections to be more flexible and to collapse with less force.

[0028] It would be advantageous to be able to laser cut from a sheet using a Nitinol frame approach, regardless of a different wire frame design, which would allow for an overall thinner impeller blade and therefore be able to be collapsed into a smaller catheter.

[0029] It may be advantageous to provide a structural frame, such as formed from at least one of a polymeric material or a metallic material, such as a nickel-titanium alloy (e.g., Nitinol), in one example, the structural frame may assume a predetermined expanded shape, e.g., the structural frame may assume a predetermined shape after transitioning from a compressed state, such as for percutaneous insertion into a patient, to an expanded state, such as in preparation for operation within the patient's vasculature.

[0030] It may be advantageous to provide a wire frame that may not be metal, but may be a resilient material other than Nitinol that has the same shape retention properties as Nitinol. The structural frame can include a wire frame. In one example, the impeller blade can be constructed from a first material, such as a first material that is elastically deformable, and a second material, such as a structural frame constructed from a material that is relatively more rigid than the first material. The structural frame, such as a structural frame constructed from a second material, can be encapsulated within the first material, such as the first material that is elastically deformable, to form the impeller blade. The encapsulated structural frame can provide a support structure for the impeller blade body.

[0031] It may be advantageous to provide a structural frame that is symmetrical, such as about the axis of an impeller. In one example, the structural frame may exhibit symmetry about a longitudinal axis, such as the longitudinal axis of a rotor. In one example, the term impeller may be used as a synonym for the term rotor.

[0032] It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative. [Means for solving the problem]

[0033] A first aspect of the invention may relate to a radially compressible and expandable rotor for a blood pump, comprising at least one impeller blade having a flexible blade body, the at least one impeller blade including a structural frame encapsulated within the blade body, the structural frame adapted to provide structure to the impeller blade body, and when expanded, the structural frame has a predetermined expanded shape.

[0034] Preferably, the structural frame is attached to an outer surface of the rotor, hi one example, the structural frame is attached to an outer surface of a longitudinally elongated rotor hub of the rotor extending along the longitudinal axis.

[0035] Preferably, the structural frame comprises one or more rotor crossing portions, each of which crosses the rotor perpendicular to the longitudinal axis of the rotor. Preferably, the rotor has one or more bores extending perpendicular to the longitudinal axis of the rotor.

[0036] Preferably, the first bore of the rotor is adapted to receive the first rotor transverse portion. Preferably, a second bore of the rotor is adapted to receive the second rotor transverse portion, the second bore being adjacent to the first bore relative to the longitudinal axis of the rotor.

[0037] Preferably, the structural frame is in the shape of a "fishbone" skeleton. Preferably, the structural frame further comprises one or more transverse coiled portions, each of which, when attached to the rotor, is respectively coiled between a wall of the bore and an outer surface of the rotor.

[0038] Preferably, the structural frame has an arcuate portion positioned between the first transverse portion and the second transverse portion. Preferably, the structural frame is in a "petal" skeletal shape.

[0039] Preferably, the structural frame is self-centering within the flexible blade body when expanded. Preferably, the structural frame is formed from a single piece of material.

[0040] Preferably, the structural frame comprises a rotor engaging frame, the rotor engaging frame adapted to secure the structural frame to the rotor. Preferably, the structural frame comprises at least one skeletal shape selected from the group of "honeycomb" cells, "diamond" cells, "rectangular" cells, a first type of "dragonfly" wing, a second type of "dragonfly" wing, a "wavy" strut wing, and a "diagonal" strut wing.

[0041] Preferably, the structural frame comprises a rotor engaging frame, the rotor engaging frame adapted to secure the structural frame to the rotor. Preferably, the rotor-engaging frame has an upper frame and a lower frame, the upper frame being parallel to the lower frame, the upper frame and the lower frame each being parallel to a longitudinal axis of the rotor.

[0042] Preferably, at least one rotor stiffening frame is connected between the upper frame and the lower frame, the rotor stiffening frame including a rotor engaging portion positioned between the upper frame and the lower frame.

[0043] Preferably, the first rotor reinforcement portion is adapted to secure a first portion of the outer surface of the rotor. Preferably, the second rotor reinforcement portion is adapted to secure a second portion of the outer surface of the rotor.

[0044] Preferably, the fixed first portion and the fixed second portion of the outer surface of the rotor are diametrically opposed to each other. In the context of the present invention, the words "comprise", "including", and the like are to be interpreted in an inclusive sense, i.e. in the sense of "including but not limited to", rather than in an exclusive sense.

[0045] The present invention should be interpreted with reference to at least one of the technical problems described in or related to the background art. The present invention aims to solve or ameliorate at least one of the technical problems, which may result in one or more advantageous effects as defined herein and described in detail with reference to preferred embodiments of the present invention.

[0046] Each of these non-limiting examples can exist alone or can be combined with one or more of the other examples in various permutations or combinations. The intent of this summary is to provide an overview of the subject matter of this patent application. It is not intended to provide an exclusive or exhaustive description of the invention. The Detailed Description is included to provide further information about this patent application.

[0047] In these drawings, which are not necessarily drawn to scale, like numerals may describe like components in different figures. Like numerals with different letter suffixes may represent different instances of like components. These drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document. [Brief description of the drawings]

[0048] [Figure 1A] 1 shows the basic anatomy of a folding blood pump. [Figure 1B] 1 shows the collapsible impeller and collapsible outer pump housing in a compressed state. [Figure 1C] FIG. 1C shows the outer sheath being removed to begin expanding the outer housing and impeller of FIG. 1B. [Figure 1D] The collapsible impeller and collapsible outer pump housing are expanded to show the deployed state in use when pumping blood. [Figure 2A] 1 shows a folding impeller body with a helical shaped wire within a polymer membrane. [Figure 2B] Also shown is a folding impeller body having a helical wire within a polymer membrane. [Diagram 3] 2C shows the folding impeller body of FIG. 2A or FIG. 2B rotated 90° about the longitudinal axis of the rotor. [Figure 4] 1 shows a folding impeller body having a petal wire frame with single (or multiple) individual half-loop reinforcement members within a polymer folding rotor. [Figure 5A] 1 shows a "fishbone" wire frame with reduced loop density within a folding impeller body. [Figure 5B] 1 illustrates another embodiment of a "fishbone" wire frame having reduced loop density within a folding impeller body, the "fishbone" wire frame being self-centering. [Figure 5C] 13A-13C show different perspective views of another embodiment of a "fishbone" wire frame within a folding impeller body. [Figure 5D] 13A-13C show different perspective views of another embodiment of a "fishbone" wire frame within a folding impeller body. [Figure 5E] 13A-13C show different perspective views of another embodiment of a "fishbone" wire frame within a folding impeller body. [Figure 5F] 13A-13C show different perspective views of another embodiment of a "fishbone" wire frame within a folding impeller body. [Figure 5G] 5C-5F show top views along the longitudinal axis of the folding rotor of any one of the folding rotors, in which the "fishbone" wire frame follows a "slalom" configuration to stiffen the folding rotor. [Figure 5H] A side view of the folding impeller body is shown, where the "fishbone" wire frame follows a "slalom" configuration that stiffens the folding rotor. [Figure 5I] FIG. 5H shows a "fishbone" wire configuration. [Figure 5J] FIG. 5G shows a "fishbone" wire configuration. [Figure 5K] FIG. 5F shows a "fishbone" wire configuration. [Figure 6] 1 shows another embodiment of the wire frame, this particular design being a "wavy strut" wire frame. [Figure 7] 1 shows the "honeycomb" wire frame design used within the folding impeller body. [Figure 8] 1 shows the "diamond" wireframe design used within the folding impeller body. [Figure 9] Shown is the first type of "Dragonfly" wireframe design engaged with a folding rotor. [Figure 10] Shown is a second type of "dragonfly" wireframe design within a folding impeller body. [Figure 11]Shown is a "honeycomb" wireframe design within the folding impeller body, with both the leading and trailing edges each extending perpendicular to the longitudinal axis of the rotor. [Figure 12] Shown is a "honeycomb" wireframe design within the folding impeller body, with both the leading and trailing edges each extending in an arc relative to the longitudinal axis of the rotor. [Figure 13] 13 shows another "honeycomb" wire frame design within another embodiment of the folding impeller body. [Figure 14] A representative diagram of an impeller body with a "honeycomb" wire design within the folding impeller body, the "honeycomb" pattern having a tendency to resist stretching and compression in directions as indicated by the direction of the arrows illustrated on the impeller body. [Figure 15] 1 shows a second type of "dragonfly" wireframe design within a folding impeller body, where both the leading and trailing edges each extend perpendicular to the longitudinal axis of the rotor. [Figure 16] 1 shows a second type of "dragonfly" wireframe design in a folding impeller body, where both the leading and trailing edges each extend in an arc relative to the longitudinal axis of the rotor. [Figure 17] 13 shows a second type of "dragonfly" wireframe design within another embodiment of a folding impeller body. [Figure 18] Shown is a "diamond" wireframe design within the folding impeller body, with both the leading and trailing edges each extending perpendicular to the longitudinal axis of the rotor. [Figure 19] 13 illustrates a "diamond" wireframe design within another embodiment of a folding impeller body. [Figure 20] 13 illustrates a "diamond" wireframe design within another embodiment of a folding impeller body. [Figure 21] A representative diagram of an impeller body with a "diamond" wire design within a folding impeller body, the "diamond" pattern having a tendency to resist stretching and compression in directions as indicated by the direction of the arrows illustrated on the impeller body. [Figure 22] 1 shows a flat laser cut design (before forming and overmolding) of another "diamond" wireframe design. [Figure 23] 1 shows the flat laser cut design (before molding and overmolding) of the "Rectangular" cell wireframe design. [Figure 24] 1 shows a flat laser cut design (before forming and overmolding) of another "honeycomb" wireframe design. [Diagram 25] 23 shows a flat laser cut design (before forming and overmolding) of another "honeycomb" wireframe design, where the size of the honeycomb cells is larger compared to the "honeycomb" wireframe design of FIG. 24. [Figure 26] 1 shows a flat laser cut design (before forming and overmolding) of the first type of "dragonfly" wireframe design. [Figure 27] 1 shows a flat laser cut design (before forming and overmolding) of the second type of "dragonfly" wireframe design. [Figure 28] 1 shows the flat laser cut design (before forming and overmolding) of the “wavy strut wing” wire frame design. [Figure 29] 1 shows the flat laser cut design (before forming and overmolding) of the “Diagonal Strut Wing” wire frame design. [Diagram 30] Shows the "rectangular" cell wireframe design within the folding impeller body. A flat laser cut design of the "rectangular" cell wireframe is presented next to this image to see the taper of the metal wireframe away from the trailing edge. [Diagram 31] A cross section (cross section AA) of FIG. 30 is shown. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings and non-limiting examples. As shown in Figures 1A-1D, the anatomical structure of a blood pump 100 is shown. The implantable blood pump 100 may include a collapsible impeller 102 mounted on a collapsible impeller cage 104. A drive means or drive cable 106 may be mounted in a housing 108, which may be connected between a first end of a catheter 110 and the collapsible impeller cage 104. The drive means 106 may be adapted to rotate the collapsible impeller 102. There may be a retractable support structure 112 (not shown) adapted to extend from the catheter 110. The extended retractable support structure may be adapted to engage the wall of the aorta to allow the implantable blood pump 100 to be fixed to the left ventricle of the heart. The collapsible impeller cage 104 may include an inlet 116 and an outlet 118. The inlet 116 of the collapsible impeller cage 104 may be adapted to receive blood from the left ventricle, and the outlet 118 may direct blood towards the atrioventricular valves of the heart. Blood may be directed or moved from the inlet 116 to the outlet 118 by rotation of the impeller 102. More specifically, the pump mechanism may be in the form of a miniature axial flow rotary mechanism including a rotating impeller 102 disposed within the impeller cage 104. The impeller cage 104 may be a collapsible nitinol frame with a flexible polymer coating 120 around the cage 104. The impeller 102 may be attached to a flexible nitinol frame rotor 122, and rotation of the drive cable or drive means 106 may in turn rotate the collapsible rotor 122, which in turn rotates the impeller 102.

[0050] The catheter 110 may be hollow and the drive cable 106 may be disposed within a lumen 124 of the hollow catheter 110. A drive shaft or rotor 122 may be connected to an end of the drive cable 106 to be rotated by the drive cable 106. The ends of the rotor 122 may engage a proximal bearing 126 and a distal bearing 128. There may be a purge system that may include holes in the hollow catheter, which may be used to pass a fluid for purging and lubricating the proximal bearing 126 and the distal bearing 128. The purge fluid may pass outside the drive cable 106 within the lumen 124 of the hollow catheter 110 in a direction from the proximal end of the hollow catheter 110 to the distal end of the hollow catheter 110.

[0051] As shown in FIG. 1A, the distal bearing 128 may be positioned between the inlet 116 of the impeller cage 104 and the atraumatic tip 138. The atraumatic tip 138 may be disposed distal to the impeller body. The atraumatic tip 138 may be flexible and may have an arcuate configuration so as to avoid traumatizing tissue when the atraumatic tip contacts tissue, for example, the inner wall of a ventricle or the endocardial surface. In some embodiments, the atraumatic tip 138 may have a J-shaped tip. In another embodiment, the most distal end of the atraumatic tip 138 may include one or more flexible coils forming a pigtail-shaped tip.

[0052] As shown in FIG. 1B, the catheter 110 may be in a compressed state where the impeller 102 and impeller cage 104 are not exposed. As shown in FIG. 1C, the catheter 110 may be in an expanded state where the outer sheath 127 is moved away from the distal bearing 128 to initiate expansion of the impeller cage 104 and impeller 102. As shown in FIG. 1D, the catheter 110 is shown in a deployed state where the impeller cage 104 and impeller 102 are expanded, showing blood being pumped by the expanded impeller 102. Collapsibility may be achieved through the use of a Nitinol wire frame that forms the collapsible impeller cage 104. The collapsible impeller cage 104 may be covered by a membrane, such as a polymer membrane.

[0053] There may be a membrane for both the impeller cage 104 or the impeller housing 104. As shown in Figures 2A, 2B, and 3, the impeller body 144 may be a polymer material and may be translucent so that the wire frame 140 or the skeletal shape of the wire frame 140 may be seen within the impeller body 144. The advantage of having a translucent flexible polymer material is that any wear and tear on the wire frame 140 with use from folding and expanding the impeller body 144 may be easily identified by eye. It may be advantageous to have the wire frame 140 follow the contour of the helical shape of the impeller body 144 so that the helical edge 148 is structurally supported. 2A, 2B, and 3, the wire frame 140 supporting the helical edge 148 may have arcuate portions, with a first arcuate wire frame portion 152 connected between a first end of a first helical wire frame portion 154 and a first end of a second helical wire frame portion 156, and a second arcuate wire frame portion 158 connected between a second end of a first helical wire frame portion 160 and a second end of a second helical wire frame portion 162. The first arcuate wire frame portion 152 may traverse through a first bore 164 of the rotor 122, and the second arcuate wire frame portion 158 may traverse through a second bore 166 of the rotor 122.

[0054] 4 illustrates an embodiment in which the folding impeller 144 may include a petal-shaped wire frame 168 formed from two extensions or two arcuate members attached by or wrapped around the rotor 122. The "petal" wire form 168 may be configured with individual half loops forming a two-bladed impeller, wrapped to reinforce the rotor 122.

[0055] FIG. 5A shows a "fishbone" wireframe 174 having a reduced loop density, and FIG. 5B shows another "fishbone" wireframe 176 having a reduced loop density while also being self-centering. Each of these "fishbone" wireframe embodiments 174 / 176 may each have a rotor crossing portion that crosses the rotor perpendicular to the longitudinal axis of the rotor 122, as shown in FIGS. 5C-5F and 5H, which are different perspective views of an impeller having the "fishbone" wireframe skeletal shape 174 / 176. It may also be described as a "slalom" configuration, in which the "fishbone" wireframe skeletal shape 174 / 176 crosses upward through a first bore 164 of the rotor 122, crosses downward through a second bore 166 of the rotor 122, then crosses upward through a third bore 180 of the rotor, and so on. A first bore 164 through the rotor 122 may be adjacent to a second bore 166, which may be adjacent to a third bore 180. FIG. 5G shows a top view of the impeller 144 with a "fishbone" wireframe skeletal shape 174 / 176. FIG. 5H shows a side view of the impeller 144, where the "fishbone" wireframe follows a "slalom" configuration that stiffens the folding rotor.

[0056] Figures 5I, 5J, and 5K may show wireform configurations from different perspectives. For example, the flat wire 174 / 176 as shown in Figure 5I may represent the wireframe 174 / 176 as seen in Figure 5H, the wireform 174 / 176 in Figure 5J may represent the wireframe 174 / 176 as seen in Figure 5G, and the wireform 174 / 176 in Figure 5K may represent the wireframe 174 / 176 as seen in Figure 5F.

[0057] Other wire frame skeleton shapes may be understood, such as a "wavy strut" wire frame 182 as shown in Figure 6, a "honeycomb" 184 or "honeycomb cell" wire frame 184 as shown in Figure 7, a "diamond" 186 or "diamond cell" wire frame 186 as shown in Figure 8, different types of "dragonfly" 188 or "drumbowing" wire frame(s) 190 as shown in Figures 9 and 10. It may also be understood that in different impeller shapes with a "honeycomb" wire frame 184 as shown in Figures 11-13, the "honeycomb" wire frame 184 may have honeycomb cells that reside between the rotor 122 and the helical edge or helical curve 148 of the impeller body 144. As shown in Figures 11, 12, and 13, there may be less metal or no metal at the corners of the impeller shape or body 144, such as the trailing edge 198 adjacent the helical turn 148 and the leading edge 200 adjacent the helical turn 148. This is so that the trailing edge 198 and the leading edge 200 will more easily fold or crush as the sheath advances from the trailing edge 198. Once the trailing edge 198 begins to collapse, the remainder of the impeller body 144 and the rotor 122 will also be more easily folded. The advantage of the "honeycomb" wire frame skeletal shape 184 is that the honeycomb pattern or hexagonal shape or cells will tend to resist stretching and compression in the plane in which it is oriented, as shown in Figure 14, where the arrow directions are depicted on the impeller body 144 as a representation. When that plane is heat set or aligned into a spiral, a compound curve can be created. These compound curves, with their planar stability, can become very resistant to deformation of the overall structure. At the same time, the voids in the plane allow temporary forces to overcome the heat set structure. The polymer movement required to collapse the impeller 144 blades is also facilitated by the "honeycomb" cellular nature 184 and the regularity of the honeycomb structure 184.

[0058] As shown in Figures 15-17, the "dragonfly" type wire frame 188 / 190 may be used with a collapsible impeller body 144. As with the "honeycomb" wire frame embodiment, there may be less metal or no metal at the corners 196 of the impeller shape, such as the trailing edge 198 adjacent the helical turn 148 and the leading edge 200 adjacent the helical turn 148. This is so that as the sheath advances from the trailing edge 198, the trailing edge 198 and the leading edge 200 will more easily fold or collapse. Once the trailing edge 198 begins to collapse, the remainder of the impeller body 144 with the "dragonfly" wire frame skeletal structure 188 / 190 and the rotor 122 will also more easily fold.

[0059] As shown in Figures 18, 19 and 20, the "diamond" type wire frame 186 may be used with a collapsible impeller body 144. As with the "honeycomb" and "dragonfly" wire frame embodiments, there may be less or no metal at the corners of the impeller shape, such as the trailing edge 198 adjacent the helical turn 148 and the leading edge 200 adjacent the helical turn 148. This is so that the trailing edge 198 and the leading edge 200 can more easily fold or collapse as the sheath advances from the trailing edge 198. As the trailing edge 198 begins to collapse, the remainder of the impeller body 144 with the "diamond" wire frame skeleton structure 186 and the rotor 122 also begin to fold easily. The expanded diamond structure 186 is advantageously used for folding in medical stents and structurally in expanded steel. The expanded diamond structure 186 is an economical way to create planar shapes with less material. Diamond structures in a plane can have different resistance to stretching and compression along different axes. The diamonds are oriented in a helical plane and can utilize compressibility or expandability as needed to aid in the collapse of the helical planar blade. A representation is shown in FIG. 21 where the outline of diamond shapes or diamond cells drawn on the impeller body 144 represents a "diamond" cell wire frame 186 and two arrows 204 indicate the compressibility and expandability of this particular wire frame structure 186. Long struts made up of multiple edges of individual diamonds or diamond cells can be utilized to generate strength by directly spanning longer distances for a given application (a property that is difficult to utilize in "honeycomb" wire frame embodiments). The polymer movement required to collapse the blade can also be facilitated by the cellular nature and regularity of the "diamond" structure 186.

[0060] Other wireframe designs are shown in flat laser cut representations as shown in Figures 22-29. More specifically, Figure 22 depicts a flat laser cut representation of a "diamond" cell 208 as shown. Figure 23 depicts a flat laser cut representation of a "rectangular" cell 210 as shown. Figure 24 depicts a flat laser cut representation of a "honeycomb" cell 212 as shown, which may be embedded in or inside the impeller body as shown in Figures 11, 12, or 13. Figure 25 depicts a larger "honeycomb" cell 214 as shown, and for comparison, the hexagonal cells of the larger "honeycomb" wireframe 214 are larger than the hexagonal cells of the smaller "honeycomb" wireframe 212 as shown in Figure 24. A possible advantage of using the larger "honeycomb" wireframe 214 is that less metal is used in the construction of this wireframe 214 as compared to the smaller "honeycomb" wireframe 212.

[0061] FIG. 26 depicts the “tonbow” wire frame 216 as shown. The “wings” 219 may be curved away from the rotor engagement means 220. Each curved “wing” 219 provides a gap 222 between the wing 219 and the rotor engagement means 220. The gap 222 may be free of metal and therefore allow for more flexibility in those areas of the impeller body 144. The increased flexibility in those areas from this wire frame design 216 of the impeller body 144 will fold or collapse more easily as the sheath advances from the trailing edge 198. Once the trailing edge 198 begins to collapse, the remainder of the impeller body with the “tonbow” wire frame skeleton structure 216 and the rotor 122 will also fold more easily. The "wings" 219 may have reinforcement with angled wing struts that may be offset relative to adjacent layers so that the angled wing struts support the center of the "wing cells" in the layer above or below. The style in the "wings" may resemble a "brick wall" configuration. FIG. 27 depicts another type of "tonbow" wire frame 228 as shown. This "wing" design 228 may have more rotor engagement means reinforcements 220. This may provide a more solid and secure attachment of the wire frame to the folding rotor 122 and / or provide a more solid and secure attachment of the wire frame design 228 to the rotor engagement means 220. There may also be angled wing struts from the edge of the wire frame 228 to the rotor engagement means reinforcements 220. The angled wing struts may be to provide additional support to the edges of the "tonbow" wire frame 228.

[0062] FIG. 28 depicts a "wavy strut wing" wire frame 230 as shown. FIG. 29 depicts a "diagonal strut wing" wire frame 232 as shown. The "wavy strut wing" or "diagonal strut wing" design 232 can have rotor engagement means 220 reinforcement 220 similar to the "tonbow wing" wire frame as shown in FIG. 26. There can be "wavy" strut supports for the "wavy strut wing" wire frame 230 and there can be "wavy" strut supports for the "diagonal strut wing" wire frame 232. The "wavy" strut supports provide structure to the impeller body 144. It also helps reduce stress in the wire frame by distributing the forces caused by transporting fluid or blood during operation to the flexible impeller body 144. As circled in FIG. 30, the taper 234 at the trailing edge 198 indicates that there may be less or no metal at the corners of the impeller shape 144, such as the trailing edge 198 adjacent the helical turn 148, and similarly at the leading edge 200 adjacent the helical turn 148. This is to allow the trailing edge 198 and leading edge 200 to more easily fold or crush as the sheath advances from the trailing edge 198. The taper 234 can be seen in the flat laser cut wireframe designs of FIGS. 22, 23, 24, 25, 26, 27, and 29. In FIG. 30, an example of a flat laser cut "rectangular" cell wireframe design 210 is shown, while a "diamond" cell wireframe design 208 is shown in a translucent impeller body 144 with the taper 234 circled to indicate that the corners 196 of the impeller shape may not have metal therein. A structural frame 140, such as the diamond-shaped cell wire frame 210, can exhibit symmetry about an axis, such as a longitudinal axis 270. In one example, the longitudinal axis 270 can be oriented parallel to the longitudinal axis of the rotor 122, e.g., the longitudinal axis 270 can be coincident with the longitudinal axis of the rotor 122.

[0063] FIG. 31 shows a cross section (section AA) of the folding impeller 102 from FIG. 30 as shown in a plane perpendicular to the longitudinal axis of the rotor 122. The blades of the folding impeller 102 may include a structural frame 104 of a second material, such as Nitinol, embedded in a blade body 292 of a first material, such as an elastically deformable polymer. The first material blade edge length 291 may define a distance from the blade attachment location 293 to the outer edge 295 of the first material, such as in a plane perpendicular to the rotor 122. The second material blade edge length 297 may define a distance from the blade attachment location 293 to the outer edge 299 of the second material, such as in the same plane used to define the first material blade edge length 291. The impeller blade gap 290 may include a distance, such as the difference between the first material blade edge length 291 and the second material blade edge length 297.

[0064] The impeller blade gap 290 may be user selectable, for example, to adjust the blade stiffness of the folding impeller 102. In one example, a folding impeller 102 with a cylindrical shape such that the radius of the rotor 122 is constant may have a first material blade edge length 291 that is constant. If the second material blade edge length 297 may vary along the longitudinal axis 270 of the rotor 122, such as the second material blade edge length 297 defined by the outer edge of the frame 210 relative to the longitudinal axis 270 at different locations along the longitudinal axis 270 shown in FIG. 30, the impeller blade gap 290 may also vary along the longitudinal axis 270.

[0065] Impeller blade clearance 290 may vary with position along rotor 122. For example, at a first location on rotor 122, a plane perpendicular to longitudinal axis 270 of rotor 122 may define a first impeller blade clearance. At a second location on rotor 122 different from the first location, a plane perpendicular to longitudinal axis 270 of rotor 122 may define a second impeller blade clearance, etc., different from the first impeller blade clearance.

[0066] Although the invention has been described with reference to specific examples, those skilled in the art will appreciate that the invention can be embodied in many other forms consistent with the broad principles of the invention described herein.

[0067] The present invention and the preferred embodiments described specifically include at least one feature that is of industrial applicability. Various notes The above description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are also referred to herein as "examples." Such examples may include elements in addition to those shown or described. However, the inventors also contemplate examples in which only the elements shown or described are provided. Moreover, the inventors also contemplate examples that use any combination or permutation of the elements shown or described (or one or more aspects of those elements) with respect to the specific example (or one or more aspects of that example) shown or described herein, or with respect to other examples (or one or more aspects of those examples) shown or described herein.

[0068] In the event of inconsistent usage between this specification and a document incorporated by reference, the usage in this specification takes precedence. The terms "1" or "one" are used herein to include one or more, as is common in patent documents, regardless of other instances or uses of "at least one" or "one or more". The term "or" is used herein to refer to a non-exclusive, such that "A or B" includes "A but not B", "B but not A", and "A and B", unless otherwise specified. The terms "including" and "in which" are used herein as the plain English equivalents of the corresponding terms "comprising" and "wherein". Also, in the following claims, the terms "comprising" and "comprising" are open-ended, i.e., a system, device, article, composition, formulation, or process that includes multiple elements in addition to those recited with such terms in the claims is still considered to be within the scope of the claims. Moreover, in the following claims, terms such as "first", "second", and "third" are used merely as labels and are not intended to impose numerical requirements on their objects.

[0069] Geometric terms such as "parallel," "orthogonal," "circular," and "square" are not intended to require absolute mathematical precision unless the context dictates otherwise. Instead, such geometric terms take into account variations due to manufacturing or equivalent functions. For example, if an element is described as "circular" or "nearly circular," parts that are not exactly circular (e.g., parts that are slightly elliptical or multi-sided polygons) are included in this description.

[0070] Examples of the methods described herein may be at least partially implemented in a machine or computer. Some examples may include a computer-readable medium or machine-readable media encoded with instructions operable to configure an electronic device to perform the methods described in the above examples. Implementations of such methods may include code such as microcode, assembly language code, high-level language code, and the like. Such code may include computer-readable instructions for performing various methods. The code may form part of a computer program product. Further, in one example, the code may be tangibly stored on one or more volatile, non-transitory, or non-volatile tangible computer-readable media, such as during execution or at other times. Examples of these tangible computer-readable media may include, but are not limited to, hard disks, removable magnetic disks, removable optical disks (e.g., compact disks and digital video disks), magnetic cassettes, memory cards or sticks, random access memory (RAM), read-only memory (ROM), and the like.

[0071] The above description is intended to be illustrative and not restrictive. For example, the above examples (or one or more aspects thereof) may be used in combination with each other. Other embodiments may be used by those skilled in the art upon review of the above description. The Abstract is provided to enable the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be construed as intending that an unclaimed disclosed feature is essential to any claim. Rather, the subject matter of the invention may lie in less than all features of a particular disclosed embodiment. Thus, it is contemplated that the following claims are incorporated into the Detailed Description as an example or embodiment, with each claim standing on its own as a separate embodiment, and that such embodiments can be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

1. A radially compressible and expandable rotor for a blood pump, An impeller blade comprising at least one flexible blade body, the at least one impeller blade comprising an elastically deformable first material, the first material being supported by a relatively rigid second material of a structural frame enclosed within the blade body, the relatively rigid second material of the structural frame being adapted to provide a support structure to the blade body, and when expanded, the structural frame having a predetermined expanded shape, The second material of the structural frame is a rotor having a shape that is symmetrical along the longitudinal axis defined by the rotor.

2. The rotor according to claim 1, wherein the structural frame is attached to the outer surface of a rotor hub that is elongated in the longitudinal direction of the rotor and extends along the longitudinal axis.

3. The rotor according to claim 2, wherein the structural frame comprises one or more rotor hub crossing portions, each of which crosses the rotor hub perpendicular to the longitudinal axis.

4. The rotor according to claim 3, wherein the rotor hub has one or more bores extending into the rotor hub perpendicular to the longitudinal axis.

5. The rotor according to claim 4, wherein one or more bores are A first bore of the rotor, adapted to receive a first rotor hub cross portion, A second bore of a rotor adapted to receive a second rotor hub cross portion, wherein the second bore is longitudinally offset from the first bore along the longitudinal axis and circumferentially offset from the first bore. A rotor equipped with a rotor.

6. The rotor according to claim 5, wherein the structural frame includes an arc-shaped portion positioned between the first rotor hub crossing portion and the second rotor hub crossing portion.

7. The rotor according to any one of claims 4 to 6, wherein the structural frame comprises one or more hub-transverse coil portions, and when the structural frame is attached to the rotor hub, each of the one or more coil portions is coiled between the wall of a corresponding bore among one or more bores and the outer surface of the rotor hub.

8. The rotor according to any one of claims 1 to 6, wherein the structural frame has a "petal" skeletal shape.

9. The rotor according to any one of claims 1 to 6, wherein the structural frame has a "fishbone" skeletal shape.

10. The rotor according to any one of claims 1 to 6, wherein the structural frame includes at least one skeletal shape selected from the group consisting of "honeycomb" cells, "diamond" cells, "rectangular" cells, "dragonfly" wings, "wavy" strut wings, and "diagonal" strut wings.

11. The rotor according to any one of claims 1 to 6, wherein the structural frame is configured to self-center within the flexible blade body when extended.

12. The rotor according to any one of claims 1 to 6, wherein the structural frame is formed from a single piece of material.

13. The rotor according to any one of claims 2 to 6, wherein the structural frame comprises a rotor engagement frame adapted to fix the structural frame to the rotor hub, the rotor engagement frame having an upper frame and a lower frame, the upper frame being parallel to the lower frame, and each of the upper frame and the lower frame being parallel to the longitudinal axis.

14. The rotor according to claim 13 comprises a first rotor reinforcing member connected between the upper frame and the lower frame, wherein the first rotor reinforcing member comprises a rotor hub engaging portion disposed between the upper frame and the lower frame and is adapted to be fixed to a first portion of the outer surface of the rotor hub.

15. The rotor according to claim 14 comprises a second rotor reinforcing member adapted to be fixed to a second portion of the outer surface of the rotor hub, wherein the fixed first portion and the fixed second portion of the outer surface of the rotor hub are diametrically opposed to each other across the longitudinal axis.

16. The rotor according to claim 1 comprises an impeller blade gap as the difference between the length of the edge of a first material blade and the length of the edge of a second material blade, wherein the impeller blade gap is selectable to adjust the rigidity of the at least one impeller blade. The at least one impeller blade extends from the elongated rotor hub at the blade mounting position, A rotor in which the blade edge length of the first material defines the distance from the blade mounting position to the outer edge of the first material of the at least one impeller blade in a plane perpendicular to the longitudinal axis, and the blade edge length of the second material defines the distance from the blade mounting position to the outer edge of the second material of the at least one impeller blade in the plane perpendicular to the longitudinal axis.

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