Transcatheter device for circulatory enhancement

Abstract

A transcatheter device for circulatory enhancement is described. The device includes in impeller with multiple blades that are configured to expand away from a central axis of the device upon deployment from a delivery sheath.

Description

TRANSCATHETER DEVICE FOR CIRCULATORY ENHANCEMENTCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. provisional application No. 63 / 640,939 filed on May 1 , 2024 incorporated herein by reference in its entirety.BACKGROUND OF THE INVENTION

[0002] All current durable and temporary pumps suffer from increased shear and stress related damage to blood cells due to vibration, eddy currents and cavitation. Cavitation caused at the blade tips lead to significant pressure drops and increases damage to blood cells. Current circulatory pumps (axial and centrifugal) both cause severe damage to blood that leads to strokes, clots, hemolysis (blood cell damage), kidney failure and a need for blood transfusion. This problem persists in micro axial pumps on the market (e.g. more than 60% of a widely used pump design demonstrates significant hemolysis, while the other 40% have been used for less time to judge hemolysis, so blood damage in a time related function in these pump designs).

[0003] Cavitation can be described as the process of formation of the vapor phase of liquid when it is subjected to reduced pressure at constant ambient temperature. Thus it is the process of boiling in liquid as a result of pressure reduction rather than heat addition, however the basic physical and thermodynamic processes are the same in both cases. A liquid is set to cavitate when vapor bubbles form and grow as aconsequence of pressure reduction. When the phase transition results from hydrodynamic pressure changes. A phase flow composed of liquid and its vapor is called cavitating flow. Cavitating flow may be seen and heard as water or blood flows through a glass venturi tube. According to Bernoulli’s equation where the velocity is increased the pressure is decreased. At sufficiently high flow rates the liquid in the throat where the velocity is highest, and the pressure is lowest begins to boil the small bubbles form there are filled with cold steam and other gases diffuse from the liquid.

[0004] Now, the application to blood and water propulsion will be discussed in more detail. As the impeller turns it absorbs the torque developed by the motor at given revolutions i.e. , the delivered horsepower - and converts that to the thrust which, in turn, pushes the blood through. According to Bernoulli’s law the passage of a hydrofoil through the blood causes a positive pressure on the face of the blade and a negative pressure on its back. It is the resolution of the pressures that results in the torque requirement and the thrust development of the impeller. The negative pressure causes any gas in solution in the blood to evolve into bubbles similar to those found when opening a bottle of lemonade or champagne. These bubbles collapse and can cause hammer like impact loads on the blades often in excess of 7 kg / cm2. It is the collapse of these bubbles that results in the observed damage to the blood cells with fragile membranes. The ratio of the absorbed power or the delivered thrust to the total blade area of the impeller is called, respectively, the power and the thrust loading. If either of these exceeds a certain value which depends upon a complex relationship between the impeller type, the flow in which it works and its mean depth below the blood relative toits diameter then the flow pattern of the blood over the impeller blades breaks down causing a severe loss of thrust and, eventually, physical damage to blood cells.

[0005] That flow breakdown is called cavitation and is strictly analogous to the water hammer often heard in old plumbing systems. Cavitation is a highly complex phenomenon and the pitting damage it causes usually - but not necessarily - appears on the back of the blade following a clear radial pattern. It can also appear as similar damage on the driving face of the impeller in which case, almost certainly, a further factor has entered the problem in the form of an incorrect pitch distribution along the length of the blade.

[0006] It is often said that cavitation is analogous to boiling with the former taking place at constant ambient temperature and the latter usually at constant ambient pressure. While the destructive potential of collapsing vapor bubbles is usually the main interest also important issues of noise and vibration due to the radiating pressures involved to be considered and taken into account. The phenomena experienced in cavitation attack are usually found to be a function of the type of cavitation met, its proximity to the blood surface and the rate of change of the cavity’s volume. When a blood suffers impeller cavitation the cell surface is subjected to a continuous bombardment of impacts from a fluctuating pressure field.

[0007] A traditional blade design is shown in prior art Fig. 1 A with prior art Figs. 1 B and 1 C illustrating vortex formation and cavitation at the blade tips. Tip vortex propeller cavitation is due to low pressure within the vortices shed at the blade tips. Boss or hub vortex cavitation is usually due to a high angle of incidence between the direction of flowof the blood and the blade leading edge in way. That form of cavitation is usually the first to show and is strongly influenced by, inter alia, the radial distribution of the impeller’s loading, the nature and variation of the effective wake field in which the impeller operates and the design of the blade tip. When the impeller has a high or sometimes even a moderate degree of skew, vortices can also appear on the outer regions of the blades leading edge which can interact often quite aggressively with the ordinary tip vortex.

[0008] Further, transcatheter pumps are limited to an extremely small impeller size and thus need very high rpms (>20,000) to run (for output) exacerbating the pitfalls above due to shearing of the cells between the impeller and shroud of the pump or blood vessels. In addition, rigidity of the impeller (usually ceramic or titanium) in these pumps make them unyielding to be intrude through smaller catheters and need different sized devices to upgrade support if needed (upgrading over time to four different sizes or more), thus greatly escalating cost and healthcare expenditure.

[0009] Accordingly, there is a need in the art for a transcatheter pump that can decrease issues of shear and stress related damage to blood cells by addressing issues such as impeller vibration, eddy currents and cavitation. Embodiments described herein fit this need while further providing several additional advantages as described in further detail below.SUMMARY OF THE INVENTION

[0010] In one embodiment, a transcatheter device for circulatory enhancement includes an impeller having multiple blades, where each of the blades is configured toexpand away from a central axis of the device upon deployment from a delivery sheath. In one embodiment, each of the plurality of blades comprises a tipless geometry. In one embodiment, each of the plurality of blades comprises an opening extending to a base of the impeller. In one embodiment, each of the plurality of blades has a substantially ribbon geometry. In one embodiment, each of the plurality of blades are connected to the base of the impeller and separated at the base of the impeller. In one embodiment, one end of each of the plurality of blades are connected to the base at a point distal of the other end. In one embodiment, each of the plurality of blades comprises at least one wire that forms a blade edge structure. In one embodiment, a flexible material is attaches to the at least one wire for forming a blade surface. In one embodiment, each of the plurality of blades comprises a first and second wire edge with a flexible material stretched therebetween. In one embodiment, each of the plurality of blades comprises a flexible material extending from a wire to a base of the impeller. In one embodiment, the device includes a stent structure surrounding the impeller. In one embodiment, the device includes a plurality of stabilizing struts connecting an impeller shaft to the stent structure. In one embodiment, the device includes a slidable and rotatable element attached to one end of each of the plurality of blades. In one embodiment, the slidable and rotatable element comprises a bearing. In one embodiment, the slidable and rotatable element is configured to lock position. In one embodiment, the slidable and rotatable element is configured to expand the plurality of blades away from a central axis upon movement along the central axis in a first direction. In one embodiment, the slidable and rotatable element is configured to draw the plurality of blades towards the central axis upon movement along the central axis in a second direction. In oneembodiment, the slidable and rotatable element is configured to change pitch of the plurality of blades towards upon rotation around the central axis.

[0011] In one embodiment, a transcatheter device for circulatory enhancement includes an impeller comprising at least one blade having an edge structure supported by a wire and a blade surface comprising a flexible material connected to the wire. In one embodiment, the flexible material extends to a base of the impeller.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The foregoing purposes and features, as well as other purposes and features, will become apparent with reference to the description and accompanying figures below, which are included to provide an understanding of the invention and constitute a part of the specification, in which like numerals represent like elements, and in which:

[0013] Figures 1 A-1 C are prior art figures of a conventional impeller.

[0014] Figure 2 is a front view of an impeller according to one embodiment.

[0015] Figure 3 is a side view of a prototype of an impeller mounted on a vascular catheter according to one embodiment.

[0016] Figure 4 is an impeller H / Q curve graph demonstrating the increased efficiency of the impeller according to embodiments described herein compared to a conventional impeller.

[0017] Figures 5A-5X are diagrams of impellers according to various embodiments.

[0018] Figures 6A and 6B show embodiments of a tipless impeller according to one embodiment, with corresponding prototype images in Figs. 6C-6L.DETAILED DESCRIPTION OF THE INVENTION

[0019] It is to be understood that the figures and descriptions of the present invention have been simplified to illustrate elements that are relevant for a more clear comprehension of the present invention, while eliminating, for the purpose of clarity, many other elements found in systems and methods of enhancing circulation. Those of ordinary skill in the art may recognize that other elements and / or steps are desirable and / or required in implementing the present invention. However, because such elements and steps are well known in the art, and because they do not facilitate a better understanding of the present invention, a discussion of such elements and steps is not provided herein. The disclosure herein is directed to all such variations and modifications to such elements and methods known to those skilled in the art.

[0020] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are described.

[0021] As used herein, each of the following terms has the meaning associated with it in this section.

[0022] The articles “a” and “an” are used herein to refer to one or to more than one ( / '.e. , to at least one) of the grammatical object of the article. By way of example, “an element” means one element or more than one element.

[0023] “About” as used herein when referring to a measurable value such as an amount, a temporal duration, and the like, is meant to encompass variations of ±20%, ±10%, ±5%, ±1 %, and ±0.1 % from the specified value, as such variations are appropriate.

[0024] Ranges: throughout this disclosure, various aspects of the invention can be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Where appropriate, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1 , 2, 2.7, 3, 4, 5, 5.3, and 6. This applies regardless of the breadth of the range.

[0025] Referring now in detail to the drawings, in which like reference numerals indicate like parts or elements throughout the several views, in various embodiments, presented herein is a transcatheter circulatory enhancement device.

[0026] Embodiments of the transcatheter circulatory enhancement device described herein include an impeller having closed looped configuration to eliminate cavitation,eliminate tip-based eddy currents by having no tips, are flexible, and are more conducive to be folded into a 9Fr (3 mm) diameter delivery catheter, and when fully opened can assume a maximum diameter of 63 Fr (21 mm) and better assume their intended and expanded / relaxed blade shape. In addition, the pitch of the blades can be adjusted to adjust flow from 5 Lt / min to 10 Lt / min. The impeller can be directly driven by motor or partially or fully shaft driven with very narrow profile. In addition, embodiments of the device have fixation stent structure for stabilization and eliminating vibration, therefore decreasing hemolysis.

[0027] In one embodiment, a transcatheter circulatory enhancement device includes an impeller with multiple tensile narrow diameter wires with stretched fabric / mem brane for example PTFE or pericardium that expands radially from a central shaft structure with a looped configuration when fully deployed. When activated and stretched the loops from the closed loop impeller blades that has an inlet and outlet. Thus, a tip is eliminated due to its rolled structure allowing the flow to move inwards and thus eliminating a tip vortex formation and differential pressures on the outside and inside of the blade thus preventing tip cavitation and blood damage. This can be viewed as a closed structure resembling and inward and outward rolled structure appearing as a loop.

[0028] Embodiments of the transcatheter circulatory enhancement device described herein have several advantages. It provides for an extremely low profile for insertion using a transcatheter technique. It also provides flexibility of application in peripheral vascular disease as well as for full cardiac support. Embodiments described herein eliminate deep cavitation vibration and hemolysis while making the pump more efficient.This also eliminates the need for any open chest procedure or any surgical incision. Since the pump can be collapsed to A9 French size in case of unexpected failure it will not obstruct the native blood flow. Given its large diameter for full cardiac support it will require less revolutions per minute compared to the current transcatheter axial pumps. For example a currently available pumps on the market require 20,000 to 30,000 RPMS for producing 3 to 5 liters of flow. In contrast, embodiments described herein will only need 2,000 to 4,000 RPMS for 7 to 10 liters of flow. Naturally, a decrease in revolutions per minute leads to less hemolysis and damage to the blood. The very low profile of insertion will further expand the indication since the skill set available is adequate to support such use.

[0029] There are also several economic advantages provided by embodiments described herein. Given the transcatheter delivery platform the usage of such a pump will vastly expand. The full support potential also eliminates the need for prolonged hospitalization and prolonged ICU stay. The design can be modified to configure the drive shaft to be delivered into a subclavian artery, thus eliminating any groin complications of bleeding and limb loss. Embodiments described herein will bring about a new modality of circulatory assistance while providing superior capabilities over existing pumps which are based on incremental innovation of unyielding non-collapsible rigid structures.

[0030] With reference now to Fig. 2, a tipless impeller 10 is shown according to one embodiment. Each tipless blade 11 has a band or ribbon shaped geometry that allows fluid to flow through it via a blade opening 12 to eliminate tip vortex formation. A transcatheter device can include an impeller having multiple blades, where each of theblades is configured to expand away from a central axis of the device upon deployment from a delivery sheath. The tipless geometry is conducive for blade loading into a catheter and blade deployment for returning to a relaxed and expanded stated. Each of the blades can have a tipless geometry and an opening extending to a base 13 of the impeller. As shown, each of the blades can have a substantially ribbon geometry. The blades are connected to the base of the impeller and separated at the base of the impeller. For example, a first end of the blade connected to the base at a first end distal of the other second end; and the first and second ends at a different spacing around the base (both the distal and circumferential spacings shown for example in Figs. 2 and 3). An experimental setup and H / Q curve is shown in Figs. 3 and 4. Fig. 3 shows an impeller mounted on a motor and vascular catheter. The impeller H / Q curve in Fig. 4, also known as a pump performance curve, illustrates the relationship between the head (H) and the flow rate (Q) for a specific pump impeller operating at a constant speed.

[0031] In one embodiment, each of the plurality of blades comprises at least one wire that forms a blade edge structure. In one embodiment, a flexible material attaches to the at least one wire for forming a blade surface. In one embodiment, each of the plurality of blades comprises a first and second wire edge with a flexible material stretched therebetween. In one embodiment, each of the plurality of blades comprises a flexible material extending from a wire to a base of the impeller. In one embodiment, the device includes a stent structure surrounding the impeller. In one embodiment, the device includes a plurality of stabilizing struts connecting an impeller shaft to the stent structure. In one embodiment, the device includes a slidable and rotatable element attached to one end of each of the plurality of blades. In one embodiment, the slidableand rotatable element comprises a bearing. In one embodiment, the slidable and rotatable element is configured to lock position. In one embodiment, the slidable and rotatable element is configured to expand the plurality of blades away from a central axis upon movement along the central axis in a first direction. In one embodiment, the slidable and rotatable element is configured to draw the plurality of blades towards the central axis upon movement along the central axis in a second direction. In one embodiment, the slidable and rotatable element is configured to change pitch of the plurality of blades towards upon rotation around the central axis. These embodiments and configurations will now be explained in more detail and with additional.

[0032] This impeller structure can be folded on itself so that it can be delivered through a 3mm that is in a nine French delivery catheter when it is fully expanded it will assume a 21 millimeter diameter that equates to 63 French diameter. The structure is contained within a fixation stent that would fix it to the aortic or vessel inner wall to reduce the vibration of the pump due to free floating catheter is eliminated. This circulatory device will have a manual activation to activate and adjust the pitch between the looped impeller blades so as to modulate the pump outflow and can be driven directly by a brushless DC motor or a coreless brushless DC motor or it can be run through a shaft that is lubricated with saline. The delivery catheter can be reduced to four or five French delivery catheter for application for insertion in peripheral arteries to maintain circulation to legs or arms or organs where the blood flow required would be in the range of 100 to 500 cc's per minute.

[0033] For full cardiac support, experimental results show that the pump impeller blade height can be adjusted to obtain a total blood flow output of five liters / min and upto 10 liters per minute. For full cardiac support the pump will have an inlet stent cannula that will extend into the left ventricular cavity with the stent fixing the pump in the ascending aorta. For peripheral vascular application a low-profile delivery catheter of 5 French will allow the pump to be placed within a stent structure and can be removable.

[0034] Embodiments of the device can use flexible blades having a band or ribbon geometry, each connected to a slidable and rotatable end. The slidable and rotatable end can for example shorten the length of each blade while extending each blade away from the central axis (via moving the end in towards the opposing end) elongate the length while drawing the blade in towards the central axis (via moving the end away from the opposing end), and change the pitch of each blade (via rotational movement of the rotatable end). An encoder can be used to move the amount of slidable or rotational distance needed so that a change in the impeller geometry can be precise.Advantageously, this flexible blade design allows the impeller to easily stretch into a thin tube then deploy to the desired geometry into a profile that if needed is larger than the footprint of conventional impeller designs.

[0035] Figs. 5A and 5B show the ascending aorta on the left-hand side and the bottom portion is the sinus of the aorta. Specifically, as shown in Fig. 5A positioned in ascending aorta, the outer fixation sheath with incorporated diffuser is endovascularly inserted and opened in the desried position. As shown in Fig. 5B, a composite inner impeller and outer fixation sheath is endovascularly inserted from femoral artery and then expanded in position. Components of the device include a flow straightener, a diffuser and an impeller (in that order). The aortic valve acts as the flow straightener, the diffuser is in the middle, followed by the impeller that has been expanded and heldin place by these two struts or multiple struts on the top and the bottom. With reference to Fig. 5C, in one embodiment, one single cylinder can be utilized to implement the impeller shape for deploying tipless blades. The position of the opening blades arranged on a shaft in flexible composition can be unfurled once at the desired position, for example by removing an outer sheath or by actuating axial movement of the cylinder (or both). A shape memory material such as nitinol can be utilized so that the unfurled cylinder expands to the desired geometry.

[0036] With reference to Fig. 5D, the different attributes of how this curved blade 100 can be configured are shown. Any of these factors can be manipulated. For example the width of the blade, the distance between the top and the bottom ends, the distance from the shaft, and the angle 102 of the blade can be manipulated.Electromagnetic actuation can implement the changes, for example by changing the height, changing the twist of a slidable / rotatable end, etc. Differential tensors may also be utilized since the whole blade does not need to be constructed of metal in certain embodiments. The blade can be made out of very thin wires on which a polyethylene or PTFE is stretched over it as a fabric body. For example, parallel wires can form edges of the blade with a material stretch therebetween, and the wires can be manipulated to get the desired shape. The wire can for example be very thin, such as .01 mm or even thinner. The body material can be porous as well. This provides the advantage of the ability to compress and deliver it through a very small delivery sheath. The wires can also triangulate, so for example, to make a particular portion thicker, two or more guide wires can be used to form the desired structure. With reference to Fig. 5E, embodiments of the device are shown sitting within the stent, showing an impeller(expandable spiral impeller) 104, motor 106, and shaft with electrical wires 108. Open cells (left) are provided for ingress of blood (e.g. a PTFE-like polymer / bovine pericardium (treated)), followed by closed duct flow and outlet 110.

[0037] With reference to Fig. 5F, three wires can be used to create three separate blades such that each wire has a layer of PTFE that is coated over it extending back to the central shaft. Steps showing gradual shape change with longitudinal shortening and radial rotation. By changing the tension in these three wires one can change the shape of the three blades. With reference to Fig. 5G, a simple design for the impeller can be implemented since a sophisticated design is often not necessary. This design illustrates an outer tube and a central shaft. The impeller deploys from the tube into a simplified impeller geometry. The wire is essentially a scaffold on which a membrane is stretched. The membrane characteristics and properties allow one to change to the shape desired.

[0038] With reference to Fig. 5H, stepwise is showing a motor, a shaft, a base, an expanded impeller, and a bearing. The bearing can be, for example, a three-point bearing. The bearing can be a hydrodynamic bearing because the water forms a small layer on which this moves and as illustrated this can be disposed within a stent. With reference to Fig. 51, bearing designs are illustrated. These may have for example three point or four-point bearings. A liquid film may separate it from the ball bearing allowing low friction movement for expanding the impeller to its functional shape. The bearing locks into place using electromagnets, slots or another locking mechanism known in the art. Illustrated are an open impeller, bearing and fixation struts (non-obstructing), a bearing with four point contact in profile and side view, an open impeller, and the shape and curvature of a blade.

[0039] With reference now to Fig. 5J, one of the biggest problems is that going directly into the artery produces a big hole in the artery that continues to bleed. So as shown, a hemostatic seal can be formed with a sheet of PTFE or Dacron with a stent at the bottom end that expands to allow the sleeve to go in and out. At the end of the procedure, once the device is taken out, only the cloth sleeve remains which can be tied off and cut it off. Time implanted may be for example 1-2 weeks. This technique will stop bleeding complications. Vascular access for large bore sheaths can be provided. This allows cardiac chamber access and hollow organ access. It can provide step in anastomosis and leave behind an indwelling catheter.

[0040] With reference to Fig. 5K, a stretched membrane is shown. A nitinol mesh or nitinol outer frame covered with polymer or treated bovine pericardium or bovine vein material may be provided. Blade shape and geometry may be defined in part by an outer nitinol wire. A blade or propeller can twist to form a series of propellers. More propellers can be added to provide more forward flow. This design shows a membrane stretching from the central axis out to the expanded wire. This embodiment is different from the previous embodiments where a central portion of the blade is hollow. With reference to Figs. 5L and 5M, the diagrams illustrate how embodiments can collapse into a sheath for delivery, showing an example stent structure 134 and opened structure 136. Segmentation 138 is shown with the outer stent 140. With reference to Fig. 5N, deployment and anchoring methods are shown. The external self expanding stent 142 and hollow impeller 144 steel guide wire with pericardium / membrane are shown.Stability anchors are deployed in both forward and backward biased directions. The ball bearing can be configured at the cap. The sheath can remove the device by collapsingthe struts and barbs as they start to close into the sheath’s narrower geometry. This way the device can pull back into the sheath (including that ball bearing) for easy removal.

[0041] With reference to Fig. 50, a final deployment into the aorta is shown. Elements include direct or shaft or partial shaft / direct combination for drive 146, collapsed 148, expanded impeller 150, systolic 152 diastolic 154 flow, ball-cup or four point contact bearing, inflow from left ventricle 156, and the driveline / catheter within the descending aorta. The advantage over other devices is illustrated here as conventional devices have a tiny diameter, so they have to run at a very high RPM. Embodiments described herein however are the size of a human aorta, from 20mm to 30mm. Less RPMs are needed for a massive passage of blood to work through. A flow of 10-15 liters per minute can be attained with less amount of blood damage due to a greatly reduced RPM.

[0042] Embodiments can navigate through the femoral artery and even in as small an artery as a coronary artery to improve blood flow. Embodiments may only need to be deployed for a couple of days, e.g. for a patient that just had a heart attack.Embodiments may be used simply to improve blood flow for a short-term period. The controller and battery can stay external since this is a short-term intervention.

[0043] With reference to Fig. 5P, the bottom shows the ventricular intake tube.Elements include a motor 158, aortic outflow 160, aortic wall 164, less material: open cells, ventricular intake, systolic and diastolic flow 168 created by motor rpm speed change, and a wire 162 within the descending aorta. As you come up, the two 1horizontal hard lines show the leaflets of the aortic valve. Moving further up is the stent structure with the bearing and then the impeller device within the stent. With the support walls on either side on the aortic walls, outflow of the impeller optimally drives flow driven by the motor. An open cell design of stent is shown. The motor has a lumen to allow passage of the guidewire and other instruments (e.g. a brushless DC motor).

[0044] With reference now to Fig. 5Q, diagrams are illustrating a wire with a differing stiffness and a membrane stretched between the wire to create the desired shape. Elements include a membrane placement 170, 174, membrane stretched 172, wire holding the membrane within, twist with membrane stretched, membrane with wire scaffold, and a collapsible component 176 that can be expanded to right shape to achieve the pre-defined structure / shape. In 2 dimensions, the impeller can be formed via twisting. Multiples can be utilized to create a multiple geometry shape. One can either stretch the membrane between two wires, or between a wire and the central axis. With reference to Fig. 5R, the leading edge (L) and trailing edge (T) are shown.Designs according to the embodiment are converting the leading edge and the trailing edge so that the blood flows over it without creating cavitation. With reference to Fig. 5S, the desired shape with Nitinol that collapse then deploys into the preformed shape. With reference to Fig. 5T, a whole deployed anatomical view is shown from the femoral artery and with the controller and power supply outside the body. With reference to Fig. 5U, embodiments of how three wires or skeletal wires within a membrane can shape and stretch the membrane are shown.

[0045] Figures 6A and 6B show embodiments of a tipless impeller according to one embodiment, with corresponding prototype images in Figs. 6C-6L. The impeller can be at least partially surrounded by a deployable impeller cage and inner / outer frame, stabilizing and centrally positioning the impeller centrally in an anatomical lumen or cavity. As shown in particular in Fig. 6B, sheaths can be utilized for advancing the entire assembly to a target area in the body. The outer-frame is deployed, followed by deployment of the inner-frame. The impeller-cage and impeller is then deployed, completing deployment of the assembly. The outer-frame stabilized the assembly central in the anatomical lumen or cavity, while the inner frame holds the impeller-cage and impeller steady and in-line with the direction of fluid flow.

[0046] The disclosures of each and every patent, patent application, and publication cited herein are hereby incorporated herein by reference in their entirety. While this invention has been disclosed with reference to specific embodiments, it is apparent that other embodiments and variations of this invention may be devised by others skilled in the art without departing from the true spirit and scope of the invention.

Claims

CLAIMSWhat is claimed is:1 . A transcatheter device for circulatory enhancement comprising: an impeller comprising a plurality of blades, wherein each of the plurality of blades is configured to expand away from a central axis of the device upon deployment from a delivery sheath.

2. The device of claim 1 , wherein each of the plurality of blades comprises a tipless geometry.

3. The device of claim 2, wherein each of the plurality of blades comprises an opening extending to a base of the impeller.

4. The device of claim 2, wherein each of the plurality of blades has a substantially ribbon geometry.

5. The device of claim 4, wherein each of the plurality of blades are connected to the base of the impeller and separated at the base of the impeller.

6. The device of claim 4, wherein one end of each of the plurality of blades are connected to the base at a point distal of the other end.

7. The device of claim 1 , wherein each of the plurality of blades comprises at least one wire that forms a blade edge structure.

8. The device of claim 7, wherein a flexible material is attaches to the at least one wire for forming a blade surface.

9. The device of claim 1 , wherein each of the plurality of blades comprises a first and second wire edge with a flexible material stretched therebetween.

10. The device of claim 1 , wherein each of the plurality of blades comprises a flexible material extending from a wire to a base of the impeller.11 . The device of claim 1 further comprising: a stent structure surrounding the impeller.

12. The device of claim 11 further comprising: a plurality of stabilizing struts connecting an impeller shaft to the stent structure.

13. The device of claim 1 further comprising: a slidable and rotatable element attached to one end of each of the plurality of blades.

14. The device of claim 13, wherein the slidable and rotatable element comprises a bearing.

15. The device of claim 13, wherein the slidable and rotatable element is configured to lock position.

16. The device of claim 13, wherein the slidable and rotatable element is configured to expand the plurality of blades away from a central axis upon movement along the central axis in a first direction.

17. The device of claim 13, wherein the slidable and rotatable element is configured to draw the plurality of blades towards the central axis upon movement along the central axis in a second direction.

18. The device of claim 13, wherein the slidable and rotatable element is configured change pitch of the plurality of blades towards upon rotation around the central axis.

19. A transcatheter device for circulatory enhancement comprising: an impeller comprising at least one blade having an edge structure supported by a wire and a blade surface comprising a flexible material connected to the wire.

20. The device of claim 19, wherein the flexible material extends to a base of the impeller.

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