Circulatory fluid flow rate reduction

Abstract

A medical implant device includes a frame at least partially defining a lumen extending through the frame from an inlet opening to an outlet opening of the frame. The device can include a first fluid guide disposed in the fluid flow path and coupled to the frame, the first fluid guide being configured to direct a portion of a fluid flow toward a first portion of the frame. A second fluid guide can be disposed in the fluid flow path and coupled to the frame at a position distal of the first fluid guide, the second fluid guide further being configured to direct the portion of the fluid flow away from the first portion of the frame.

Description

CIRCULATORY FLUID FLOW RATE REDUCTIONCROSS REFERENCE TO RELATED APPLICATION(S)

[0001] This application claims the benefit of U.S. Application No. 63 / 552,044, filed February 9, 2024, the disclosure of which is hereby expressly incorporated by reference herein in its entirety for all purposes.BACKGROUND

[0002] Overactivation of the sympathetic nervous system, for example as a result of heart failure, can result in an over-recruitment of blood-flow from the splanchnic compartment to the cardiopulmonary circuit. This over-recruitment of blood flow can increase blood flow to the venous system, which can thereby lead to increased cardiac preload to the right heart.SUMMARY

[0003] Described herein are methods and devices relating to reducing a fluid flow rate, such as a blood flow rate within a blood vessel. In some instances, a flow rate reducer can comprise a frame at least partially defining a lumen extending therethrough to provide a fluid flow path from an inlet opening to an outlet opening of the frame. The flow rate reducer can comprise a fluid guide structure, arrangement and / or feature comprising a plurality of fluid guides disposed in the fluid flow path. Each of the plurality of fluid guides can be coupled to respective portions of the frame. The fluid guides can direct the flow direction of at least a portion of the fluid flow, such as to provide turbulence in the flow and thereby slow the forward flow velocity. In some instances, a flow rate reducer can comprise a first fluid guide, a second fluid guide, a third fluid guide, and a fourth fluid guide, disposed along the fluid flow path within the frame. In some instances, a flow rate reducer can comprise a fluid guide structure, arrangement and / or feature comprising a truncated conical fluid guide and / or a plunger fluid guide. In some instances, a medical assembly can comprise a plurality of flow rate reducers configured to be arranged end-to-end to provide a reduced flow rate. Each of the plurality of flow rate reducers can comprise a plurality of fluid guides configured to direct the flow direction of at least a portion of the fluid flow to generate turbulence in the fluid flow and reduce forward flow velocity.

[0004] Methods and structures disclosed herein for treating a patient also encompass analogous methods and structures performed on or placed on a simulated patient, which is useful, for example, for training; for demonstration; for procedure and / or device development; and the like. The simulated patient can be physical, virtual, or a combination of physical and virtual. A simulation can include a simulation of all or a portion of a patient, for example, an entire body, a portion of a body (e.g. , thorax), a system (e.g. , cardiovascular system), an organ (e.g., heart), or any combination thereof. Physical elements can be natural, including human or animal cadavers, or portions thereof; synthetic; or any combination of natural and synthetic. Virtual elements can be entirely in silico, or overlaid on one or more of the physical components. Virtual elements can be presented on any combination of screens, headsets, holographically, projected, loud speakers, headphones, pressure transducers, temperature transducers, or using any combination of suitable technologies.

[0005] For purposes of summarizing the disclosure, certain aspects, advantages, and novel features have been described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any particular example. Thus, the disclosed examples may be carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Various examples are depicted in the accompanying drawings for illustrative purposes and should in no way be interpreted as limiting the scope of the inventions. In addition, various features of different disclosed examples can be combined to form additional examples, which are part of this disclosure. Throughout the drawings, reference numbers may be reused to indicate correspondence between reference elements. However, it should be understood that the use of similar reference numbers in connection with multiple drawings does not necessarily imply similarity between respective examples associated therewith. Furthermore, it should be understood that the features of the respective drawings are not necessarily drawn to scale, and the illustrated sizes thereof are presented for the purpose of illustration of inventive aspects thereof. Generally, certain of the illustrated features may be relatively smaller than as illustrated in some examples or configurations.

[0007] Figure 1 provides a cross-sectional view of a portion of a human circulatory system, and examples of flow rate reducers deployed therein.

[0008] Figure 2A provides a side cross-sectional view of a flow rate reducer in accordance with one or more examples.

[0009] Figures 2B and 2C provide a perspective view and an end view, respectively, of a fluid guide associated with the flow rate reducer shown in Figure 2A.

[0010] Figures 2D and 2E provide a perspective view and an end view, respectively, of a fluid guide associated with the flow rate reducer shown in Figure 2A.

[0011] Figure 3A provides a side cross-sectional view of a flow rate reducer in accordance with one or more examples.

[0012] Figures 3B and 3C provide a perspective view and an end view, respectively, of a fluid guide associated with the flow rate reducer shown in Figure 3A.

[0013] Figure 4 provides a side view of an implant assembly comprising two flow rate reducers tandemly arranged in accordance with one or more examples.

[0014] Figure 5 is a flow diagram of an example of a process for reducing a fluid flow rate using a flow rate reducer in accordance with one or more examples.

[0015] Figure 6A is a perspective view of a flow rate reducer comprising truncated conical fluid guide in accordance with one or more examples.

[0016] Figures 6B and 6C are end views, of the truncated conical fluid guide described with reference to Figure 6A, in a first state and a second state, respectively.

[0017] Figure 7A is a perspective view of a flow rate reducer comprising truncated conical fluid guide having a plurality of leaflets, in accordance with one or more examples.

[0018] Figures 7B and 7C are end views, of the truncated conical fluid guide described with reference to Figures 7 A and 7B, in a first state and a second state, respectively.

[0019] Figures 8 A and 8B are side views of a flow rate reducer comprising a plunger fluid guide in accordance with one or more examples.

[0020] Figure 9 is a side view of a flow rate reducer comprising a plunger fluid guide having an orientation opposite that described with reference to Figures 8 A and 8B, in accordance with one or more examples.DETAILED DESCRIPTION

[0021] The headings provided herein are for convenience only and do not necessarily affect the scope or meaning of the claimed invention.

[0022] Although certain preferred examples are disclosed below, inventive subject matter extends beyond the specifically disclosed examples to other alternative examples and / or uses and to modifications and equivalents thereof. Thus, the scope of the claims that may arise herefrom is not limited by any of the particular examples described below. For example, in any method or process disclosed herein, the acts or operations of the method or process may be performed in any suitable sequence and are not necessarily limited to any particular disclosed sequence. Various operations may be described as multiple discrete operations in turn, in a manner that may be helpful in understanding certain examples; however, the order of description should not be construed to imply that these operations are order dependent. Additionally, the structures, systems, and / or devices described herein may be embodied as integrated components or as separate components. For purposes of comparing various examples, certain aspects and advantages of these examples are described. Not necessarily all such aspects or advantages are achieved by any particular example. Thus, for example, various examples may be carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other aspects or advantages as may also be taught or suggested herein.

[0023] Certain standard anatomical terms of location are used herein to refer to the anatomy of animals, and namely humans, with respect to the preferred examples. Although certain spatially relative terms, such as “outer,” “inner,” “upper,” “lower,” “below,” “above,” “vertical,” “horizontal,” “top,” “bottom,” and similar terms, are used herein to describe a spatial relationship of one device / element or anatomical structure to another device / element or anatomical structure, it is understood that these terms are used herein for ease of description to describe the positional relationship between element(s) / structures(s), as illustrated in the drawings. It should be understood that spatially relative terms are intended to encompass different orientations of the element(s) / structures(s), in use or operation, in addition to the orientations depicted in the drawings. For example, an element / structure described as “above” another element / structure may represent a position that is below or beside such other element / structure with respect to alternate orientations of the subject patient or element / structure, and vice-versa.

[0024] Figure 1 provides a cross-sectional view of a portion of a human vasculature, including a heart 1. The heart 1 includes four chambers, namely the left atrium 2, the left ventricle 3, the right ventricle 4, and the right atrium 5. A wall of muscle, referred to as the septal wall 10, separates the left atrium 2 and right atrium 5, and the left ventricle 3 and right ventricle 4. Blood flow through the heart 1 is at least partially controlled by four valves,the mitral valve 6, aortic valve 7, tricuspid valve 8, and pulmonary valve 9. The mitral valve 6 separates the left atrium 2 and the left ventricle 3 and controls blood flow therebetween. The aortic valve 7 separates and controls blood flow between the left ventricle 3 and the aorta 12. The tricuspid valve 8 separates the right atrium 5 and the right ventricle 4 and controls blood flow therebetween. The pulmonary valve 9 separates the right ventricle 4 and the pulmonary trunk or artery 11 , controlling blood flow therebetween.

[0025] In a healthy heart, deoxygenated blood arriving from the rest of the body generally flows into the right side of the heart 1 for transport to the lungs, and oxygenated blood from the lungs generally flows into the left side of the heart 1 for transport to the rest of the body. For example, during atrial diastole, deoxygenated blood from the inferior and superior venae cavae 8, 9 and coronary sinus (not shown) can flow into the right atrium 5. Oxygen-rich blood from the lungs can flow into the left atrium 2 through the four pulmonary veins (not shown). During atrial systole, as the atrial cardiac muscles contract, blood can be pumped from the right and left atria 5, 2 into the right and left ventricles 4, 3 through the mitral valve 6 and the tricuspid valve 8, respectively. The ventricles can be in a diastole phase while deoxygenated blood from the right atrium 5 flow into the right ventricle 4, and oxygenated blood from the left atrium 2 flow into the left ventricle 3. During ventricular systole, deoxygenated blood from the right ventricle 4 can flow into the pulmonary trunk (not shown) for transport to the lungs (e.g., via the left and right pulmonary arteries), and oxygenated blood can flow from the left ventricle 3 to the aorta (not shown) for transport to the rest of the body.

[0026] Heart failure can involve a number of compensatory mechanisms which can harm the heart. For example, a sympathetic nervous system overactivation can cause an over-recruitment of blood-flow from the splanchnic compartment (e.g. , unstressed volume) to the cardiopulmonary circuit e.g., stressed volume). This over-recruitment of blood flow can increase blood flow to the venous system, which can thereby lead to increased cardiac preload to the right heart. Increased cardiac preload can subsequently increase blood flow to the left side of the heart, leading to congestion and further remodeling of the myocytes.

[0027] Described herein are devices, systems and methods relating to reducing a blood flow rate, for example a forward flow velocity of the blood. In some instances, a flow rate reducer can be configured to slow the flow rate of a fluid flowing therethrough. The flow rate reducer can comprise a frame with an inlet opening at a first end and an outlet opening at a second end. The frame can at least partially define a lumen extending therethrough to provide a fluid flow path from the inlet opening to the outlet opening. The flow rate reducercan comprise a fluid guide structure, arrangement and / or feature having one or more fluid guides configured to be in the fluid flow path. Each of the plurality of fluid guides can be coupled to respective portions of the frame. Fluid flow past the one or more fluid guides can provide a reduced flow rate at the outlet opening as compared to that at the inlet opening.

[0028] In some instances, the fluid guide structure, arrangement and / or feature can comprise a plurality of fluid guides that can redirect a direction of at least a portion of the fluid flow, thereby providing turbulence in the flow and slowing the forward flow velocity. In some instances, a flow rate reducer can comprise a first fluid guide, a second fluid guide, a third fluid guide, and a fourth fluid guide, disposed sequentially along the fluid flow path within the frame. The first fluid guide can divide the incoming fluid flow into a first and second fluid flow portion. The first fluid guide can deflect the first portion of the incoming fluid flow toward the second fluid guide disposed along a first portion of the frame, while allowing the second portion of the incoming fluid flow to flow distally. The second fluid guide can direct the first portion of the fluid flow away from the first portion of the frame and into the second fluid flow portion, for example introducing turbulence and providing a slowed fluid flow. The slowed fluid flow can flow distally within the frame. The third and fourth fluid guides can provide redirection of at least a portion of the slowed fluid flow to provide a further slow-down in forward flow velocity. For example, the slowed fluid flow can flow past the third fluid guide to be divided into two fluid flow portions, the third fluid guide deflecting a first of the two fluid flow portion toward the fourth fluid guide at least partially disposed along another portion of the frame. The second of the two fluid flow portions can be allowed to flow distally. The fourth fluid guide can direct the first of the two fluid flow portions into the second of the two fluid flow portions, thereby introducing further turbulence and providing a further slowed fluid flow. In some instances, the flow rate reducer can be configured to provide a greater decrease in forward flow velocity with increased inlet flow velocity.

[0029] In some instances, the fluid guide structure, arrangement and / or feature can comprise a truncated conical fluid guide. The truncated conical fluid guide can have a first smaller opening oriented toward the inlet opening of the frame and a second larger opening oriented toward the outlet opening. The truncated conical fluid guide can be reversibly foldable upon itself to reduce a size of the first smaller opening in response to pressure exerted upon the truncated conical fluid guide by fluid flowing through the inlet opening. Reduction in size of the first smaller opening can provide a reduced forward flow velocity. In some instances, a truncated the truncated conical fluid guide can comprise aunitary flexible membrane. For example, the flexible membrane can form or substantially form a truncated conical shape. The flexible membrane can at least partially define the first and second openings. In alternative instances, a truncated conical fluid guide can comprise a plurality of leaflets circumferentially disposed around a portion of the lumen defined by the frame. The plurality of leaflets can form or substantially form the truncated conical shape, respective edges of the leaflets at least partially defining the first and second openings of the truncated conical fluid guide. The plurality of leaflets can reversibly move toward each other in response to pressure exerted thereupon by fluid flowing through the inlet opening of the frame. In some instances, each of the plurality of leaflets can be spaced from respective adjacent leaflets. Movement of the leaflets toward one another can reduce the size of the first opening and / or spacing between adjacent leaflets, thereby providing the reduced outlet flow rate.

[0030] In some instances, the fluid guide structure, arrangement and / or feature can comprise a plunger fluid guide. The frame can comprise a narrowed portion, for example comprising a neck portion. The plunger fluid guide can be disposed in a portion of the lumen on an inlet side relative to the narrowed portion. In some instances, the plunger fluid guide can assume a teardrop shape. The plunger fluid guide can be reversibly movable toward and away from the narrowed portion of the frame to provide the reduced outlet flow rate.

[0031] It will be understood that a fluid flow reducer can comprise one or more of the fluid guide structures, arrangements and / or features described herein. In some instances, a fluid flow reducer can comprise a frame and one or more fluid guides as described herein disposed in the frame in series to provide a reduced outlet flow rate.

[0032] In some instances, a medical assembly can comprise a plurality of flow rate reducers. Each of the flow rate reducers can comprise a plurality of fluid guides. In some instances, a medical assembly can comprise a first and a second flow rate reducer configured to be arranged tandemly. For example, each flow rate reducer can comprise a first and a second fluid guide. One or more features of the medical assembly can be selected to achieve desired slowdown in forward flow velocity between an inlet flow rate at an inlet opening of the first flow rate reducer and an outlet flow rate at an outlet opening of a last one of the flow rate reducers, such as the second flow rate reducer.

[0033] Figure 1 shows example locations within the vasculature to which a flow rate reducer can be deployed, such as providing an endoluminal reduction of blood flow rate at the respective locations. A flow rate reducer can be sized and / or shaped for positioning at a location within the venous vasculature. For example, a first flow rate reducer 100 can bedeployed into the inferior vena cava (IVC) 8. In some instances, the first flow rate reducer 100 can be positioned at a location in the inferior vena cava (IVC) 8 at or proximate to the right atrium 4. For example, an inlet opening 102 can be oriented away from the right atrium 4. An outlet opening 104 of the first flow rate reducer 100 can be oriented toward the right atrium 4 such that the flow rate reducer 100 can provide a slowed blood flow rate into the right atrium 4. In some instances, the outlet opening 104 can be at or proximate to an opening of the right atrium 4 through which blood flows from the inferior vena cava (IVC) 8 into the right atrium 4.

[0034] In some instances, a flow rate reducer can be deployed to another location in the inferior vena cava (IVC) 8. For example, a flow rate reducer can be deployed to a portion the inferior vena cava (IVC) 8 between where the hepatic veins and renal veins drain into the inferior vena cava (IVC) 8. In some instances, a flow rate reducer can be deployed to another location in the venous blood flow path. In some instances, a flow rate reducer can be deployed to a portion of a portal vein. In some instances, a flow rate reducer can be deployed to a hepatic vein.|0035| Referring again to Figure 1, in some instances, a flow rate reducer can be deployed into the superior vena cava (SVC) 9. A second flow rate reducer 150 can be deployed into the superior vena cava (SVC) 9. In some instances, the second flow rate reducer 150 can be positioned at a location in the superior vena cava (SVC) 9 at or proximate to the right atrium 4. For example, an inlet opening 152 can be oriented away from the right atrium 4 and an outlet opening 154 of the second flow rate reducer 150 can be oriented toward the right atrium 4 such that the second flow rate reducer 150 can provide a slowed blood flow rate into the right atrium 4. In some instances, the outlet opening 154 can be at or proximate to an opening of the right atrium 4 through which blood flows from the superior vena cava (SVC) 9 into the right atrium 4.

[0036] The flow rate reducers described herein can dampen effects of sympathetic nervous system overactivation, such as by reducing blood flow rate in a portion of the venous system. Providing a reduced blood flow rate in a portion of the venous system can reduce blood flow into the right heart, for example reducing cardiac preload to the right heart. Decreased cardiac preload can subsequently decrease blood flow to the left side of the heart, and thereby relieve and / or prevent heart congestion. In some instances, dampening effect provided by a flow rate reducer can depend on an inlet flow rate, for example providing greater reduction in a forward flow velocity with larger forward inflow velocity.

[0037] Flow rate reducing devices described herein can be delivered using minimally invasive transcatheter delivery procedures. In some instances, delivery of one or more flow rate reducers can comprise insertion into a femoral vein for advancement to a target site. In alternative instances, the devices can be inserted into any number of other vessels and / or lumens. In some instances, the flow rate reducer can be advanced into a femoral vein through an access opening, and from the femoral vein into an inferior vena cava. In some instances, the flow rate reducer can be advanced into a jugular vein through an access opening, and from the jugular vein into a superior vena cava.

[0038] It will be understood that one or more components of the flow -reducing devices can undergo various processes in preparation for their use in the procedures, including for example sterilization processes. The flow-reducing devices can be sterilized flow-reducing devices.

[0039] The term “associated with” is used herein according to its broad and ordinary meaning. For example, where a first feature, element, component, device, or member is described as being “associated with” a second feature, element, component, device, or member, such description should be understood as indicating that the first feature, element, component, device, or member is physically coupled, attached, or connected to, integrated with, embedded at least partially within, or otherwise physically related to the second feature, element, component, device, or member, whether directly or indirectly.

[0040] Methods and structures disclosed herein for treating a patient also encompass analogous methods and structures performed on or placed on a simulated patient, which is useful, for example, for training; for demonstration; for procedure and / or device development; and the like. The simulated patient can be physical, virtual, or a combination of physical and virtual. A simulation can include a simulation of all or a portion of a patient, for example, an entire body, a portion of a body (e.g. , thorax), a system (e.g. , cardiovascular system), an organ (e.g., heart), or any combination thereof. Physical elements can be natural, including human or animal cadavers, or portions thereof; synthetic; or any combination of natural and synthetic. Virtual elements can be entirely in silico, or overlaid on one or more of the physical components. Virtual elements can be presented on any combination of screens, headsets, holographically, projected, loud speakers, headphones, pressure transducers, temperature transducers, or using any combination of suitable technologies.

[0041] Flow rate reducers described herein, including those described with reference to Figures 2A through 2E, 3A through 3C, 4, 6A through 6C, 7A through 7C, 8A and 8A and 9 can be deployed to one or more locations described herein, including withreference to Figure 1. A size of the flow rate reducers can depend on the location of deployment. In some instances, a diameter of a flow rate reducer can be about 5 millimeters (mm) to about 25 millimeters (mm), including about 10 millimeters (mm) to about 25 millimeters (mm), and about 10 millimeters (mm) to about 15 millimeters (mm). In some instances, a diameter of a flow rate reducer can be about 15 millimeters (mm) to about 40 millimeters (mm), including about 15 millimeters (mm) to about 35 millimeters (mm), and about 20 millimeters (mm) to about 35 millimeters (mm).

[0042] Figures 2A, 2B, 2C, 2D and 2E show various views of an example of a flow rate reducer 200 comprising a fluid guide structure, arrangement and / or feature that includes a plurality of distinct fluid guides arranged in series along a fluid flow path. Figure 2A is a side cross-sectional view of the flow rate reducer 200. Figure 2B is a perspective view, and Figure 2C is an end view, of a first fluid guide of the flow rate reducer 200. Figure 2D is a perspective view, and Figure 2E is an end view, of a second fluid guide of the flow rate reducer 200. The flow rate reducer 200 can be configured to slow the flow rate of a fluid flowing therethrough. For example, the flow rate reducer 200 can be deployed to a target location in the vasculature of the venous system. The flow rate reducer 200 can dampen the blood flow rate through a portion of the venous system such that blood flow rate into the heart can be slowed. Referring to Figure 2A, the flow rate reducer 200 can comprise a frame 202. The frame 202 can comprise an inlet opening 208 and an outlet opening 210. For example, the inlet opening 208 can be at a first end 204 of the frame 202. The outlet opening 210 can be at a second end 206 of the frame 202. The frame 202 can at least partially define a fluid flow path therethrough, such as from the inlet opening 208 to the outlet opening 210. In some instances, the frame 202 can at least partially define a lumen 212 extending therethrough. For example, the frame 202 can comprise any number of conduit structures that can at least partially define the lumen 212. Fluid flow, such as blood flow, can flow through the frame 202 from the inlet opening 208 to the outlet opening 210 through the lumen 212. The lumen 212 can be aligned, parallel and / or coaxial with the fluid flow direction at the inlet opening 208. In some instances, the flow rate reducer 200 can be deployed into a blood vessel such that externally oriented surface portions of the frame 202 can engage with respective portions of the blood vessel wall at the target location to maintain the position of the flow rate reducer 200. For example, one or more externally oriented surface portions of the frame 202 can be in contact with the blood vessel wall to facilitate anchoring of the flow rate reducer 200. At least a portion of the blood flow past the location can flow through the lumen 212. In some instances, all or substantially all of the blood flow past the location in the blood vesselcan travel through the lumen 212 defined by the frame 202 such that flow rate of the blood can be slowed. The flow rate reducer 200 can comprise a plurality of fluid guides, such as the first fluid guide 220, the second fluid guide 240, a third fluid guide 260, and a fourth fluid guide 280, each configured to be in the fluid flow path. The first, second, third and fourth fluid guides 220, 240, 260, 280 can be arranged sequentially one after the other, for example in tandem, within the frame 202. For example, the first fluid guide 220 can be at a proximal- most position, such as closest to the inlet opening 208 and the fourth fluid guide 280 can be at a distal-most position, such as closest to the outlet opening 210. A longitudinal axis of the frame 202 can extend between the inlet and outlet openings 208, 210. In some instances, each of the fluid guides 220, 240, 260, 280 can be disposed along a respective longitudinal portion of the frame 202. In some instances, respective end portions of adjacent fluid guides can be disposed along overlapping longitudinal portions of the frame 202. Alternatively, each of the fluid guides 220, 240, 260, 280 can be disposed along non-overlapping longitudinal portions of the frame 202. In some instances, the fluid guides 220, 240, 260, 280 can be in a sequential end-to-end arrangement. Flowing, passing and / or injecting the fluid past the plurality of fluid guides can slow the flow rate. In some instances, the flow rate reducer 200 can allow directional flow therethrough. For example, one or more of the fluid guides can be configured to reduce or prevent retrograde fluid flow through the flow rate reducer 200, while allowing antegrade fluid flow therethrough.

[0043] Referring again to Figure 2A, at least a portion of the first fluid guide 220 can be disposed in the fluid flow path. The fluid, such as a distally flowing fluid, can flow through the inlet opening 208 at the first end 204 and into the lumen 212. Flowing the fluid past the first fluid guide 220 can divide the fluid flow into a first and a second fluid flow portion. In some instances, the fluid flow can be divided into equal or substantially equal portions. The first fluid guide 220 can be configured to direct the first fluid flow portion toward the frame 202, while allowing the second fluid flow portion to flow distally. For example, the first fluid guide 220 can provide a ramp to direct and / or deflect the first fluid flow portion toward a first portion 214 of the frame 202. The first fluid guide 220 can change and / or affect the flow direction of the first fluid flow portion, such as direct the fluid flow portion away from the longitudinal axis of the frame 202, including toward the first portion 214 of the frame 202. The first fluid guide 220 can allow the second fluid flow portion to continue along its flow path without or substantially without changing its flow direction, including continue a distal flow direction. In some instances, the second fluid flow portion can flow along a direction parallel or substantially parallel to the longitudinal axis of theframe 202. For example, the second fluid flow portion can comprise an undirected or substantially undirected fluid flow portion. Arrows in Figure 2A illustrate examples of fluid flow directions.

[0044] At least a portion of the second fluid guide 240 can be disposed in the fluid flow path distal of the first fluid guide 220. The second fluid guide 240 can be configured to change the direction of the first fluid flow portion, for example directing and / or deflecting the first fluid flow portion away from the frame 202, such as away from the first portion 214 of the frame 202. For example, the second fluid guide 240 can be configured to be in the flow path of the first fluid flow portion after the first fluid flow portion is directed toward the first portion 214 of the frame 202. The first fluid flow portion can flow past the first fluid guide 220 and into the second fluid guide 240. The first fluid guide 220 can direct the first fluid flow portion toward and / or into the second fluid guide 240. In some instances, at least a portion of the second fluid guide 240 can be disposed at a position that is at or proximate to the first portion 214 of the frame 202. In some instances, the first fluid flow portion can flow into the second fluid guide 240 such that the first fluid flow portion is directed away from the first portion 214 of the frame 202. In some instances, the second fluid guide 240 can provide a path comprising an arcuate portion to direct the first fluid flow portion away from the frame 202. The second fluid guide 240 can comprise a curved surface portion oriented toward the fluid flow to guide the fluid flow away from the first portion 214 of the frame 202. The second fluid guide 240 can direct the first fluid flow portion toward the longitudinal axis of the frame 202. The first fluid flow portion can subsequently flow into the second fluid flow portion flowing along a distally extending direction. For example, after the first fluid flow portion is directed away from the first portion 214 of the frame 202, the first fluid flow portion can be combined with the second fluid flow portion. Flowing the first fluid flow portion past the second fluid guide 240 can provide a combined fluid flow comprising the first and second fluid flow portions. Flowing the first fluid flow portion into the second fluid flow portion can slow the fluid flow rate. For example, the first and second fluid guides 220, 240 together can generate turbulence in the fluid flow to slow the forward flow velocity.

[0045] Flowing the combined fluid flow past the third and fourth fluid guides 260, 280 can further slow down the flow rate, such as the forward flow velocity. The third fluid guide 260 can be disposed distally of the second fluid guide 240. In some instances, at least a portion of the third fluid guide 260 can be disposed in the fluid flow path to divide the fluid flow into two portions. For example, flowing the combined fluid flow past the third fluid guide 260 can divide the combined fluid flow into the two portions, including two equal orsubstantially equal portions. The third fluid guide 260 can provide a ramp to direct and / or deflect one of the two fluid flow portions toward the frame 202, such as a second portion 216 of the frame 202. The third fluid guide 260 can change and / or alter the direction of one of the two fluid flow portions, for example directing the one fluid flow portion away from the longitudinal axis of the frame 202. In some instances, the second portion 216 at a position that is rotated about a longitudinal axis of the frame 202 relative to the first portion 214 of the frame 202. In some instances, the second portion 216 can be a portion of the frame 202 that is distal of and opposingly oriented around the longitudinal axis and / or a circumference of the frame 202 relative to the first portion 214. The third fluid guide 260 can allow the other of the two fluid flow portions to flow distally, for example without or substantially without changing and / or affecting the flow direction of the other fluid flow portion. The combined fluid flow can be divided into a third fluid flow portion and a fourth fluid flow portion. The third fluid flow portion can be directed toward the second portion 216 of the frame 202. The fourth fluid flow portion can flow along a distally extending direction past the third fluid guide 260, including along a direction parallel or substantially parallel to the longitudinal axis of the frame 202. For example, the fourth fluid flow portion can comprise an undirected or substantially undirected fluid flow portion.

[0046] In some instances, the third fluid flow portion can flow to the fourth fluid guide 280. The fourth fluid guide 280 can direct and / or deflect the third fluid flow portion away from the frame 202. At least a portion of the fourth fluid guide 280 can be disposed in the fluid flow path distally of the third fluid guide 260. In some instances, at least a portion of the fourth fluid guide 280 can be disposed at a position that is at or proximate to the second portion 216 of the frame 202. In some instances, the third fluid flow portion can flow into the fourth fluid guide 280 such that the third fluid flow portion is directed away from the second portion 216 of the frame 202. The fourth fluid guide 280 can provide a path comprising an arcuate portion to direct the third fluid flow portion away from the frame 202. The third fluid flow portion can subsequently flow into the fourth fluid flow portion after the third fluid flow portion is directed away from the second portion 216 of the frame 202. For example, the fourth fluid guide 280 can direct the third fluid flow portion toward the longitudinal axis of the frame 202. The third and fourth fluid flow portions can subsequently be combined. Flowing the third and fourth fluid portions together can generate turbulence, thereby slowing the fluid flow rate, such as the forward flow velocity. The flow rate can be further slowed, such as compared to that after the second fluid guide 240. Fluid flowing out of the outlet opening 210 can comprise the combined fluid flow after the third fluid flow portion flowsinto the fourth fluid flow portion. The flow rate at the outlet opening 210 can be slower than that at the inlet opening 208.

[0047] Figures 2B and 2C provide a perspective view and an end view of the first fluid guide 220, respectively. The first fluid guide 220 can be coupled to the frame 202 at a first position. For example, the first fluid guide 220 can comprise a first end 220a and a second end 220b. The first end 220a can be oriented toward the inlet opening 208. The second end 220b can be oriented toward the outlet opening 210. The first end 220a can be coupled to first corresponding portions of the frame 202. The second end 220b can be coupled to the frame 202 at second corresponding portions disposed distally from the first corresponding portions. In some instances, the first end 220a can be at or proximate to the first end 204 of the frame 202. For example, the first fluid guide 220 can extend distally from the first end 204 of the frame 202. In some instances, the first end 220a can extend along a lateral dimension, such as a diameter, of the frame 202. The first end 220a can be coupled to opposing portions disposed around a circumference of the frame 202. In some instances, disposing the first end 220a along the diameter of the frame 202 can facilitate division of the incoming fluid flow into two equal or substantially equal portions. Alternatively, the first end 220a may not extend along the diameter of the frame 202, for example dividing the incoming fluid flow into two unequal fluid flow portions. In some instances, the first end 220a can extend along a dimension that is off-center and parallel or substantially parallel to the diameter of the frame 202.

[0048] In some instances, the first fluid guide 220 can comprise an arcuate shape along a lateral dimension. The arcuate shape can direct the fluid flow toward the first portion 214 of the frame 202. For example, the arcuate shape can deflect the flow of the fluid and direct the fluid flow toward the frame 202. The first fluid guide 220 can comprise a first and second side 220c, 220d extending between the first and second ends 220a, 220b. The first and second ends 220a, 220b and first and second sides 220c, 220d can form respective edges of the first fluid guide 220. The first and second sides 220c, 220d can be configured to be oriented toward respective portions of the frame 202, for example extending along the respective portions of the frame 202. In some instances, at least a portion of each of the first and second sides 220c, 220d can be coupled to the respective portions of the frame 202. One or more comers and / or edges of the first fluid guide 220 can be coupled to the frame using any number of techniques, such as sewing. At least a portion of the first fluid guide 220 can comprise a curvature extending along a lateral dimension thereof. The lateral dimension can be perpendicular or substantially perpendicular to the longitudinal axis of the frame 202. Forexample, a dimension extending between opposing portions of the first and second sides 220c, 220d can comprise a curvature. The curvature can curve toward the first portion 214 of the frame 202. For example, the lateral dimension can extend along a curved path from the first side 220c to the second side 220d such that a medial portion of the first fluid guide 220 along the curved path is disposed laterally closer to the first portion 214 of the frame 202 than remaining portions of the fluid guide 220 along the curved path. In some instances, a cross section of the first fluid guide 220 along a lateral dimension can comprise a segment of an oval. In some instances, a portion of the fluid guide 220 can comprise the curvature along its longitudinal dimension. In some instances, the degree of curvature along the lateral dimension can increase along a distally extending direction. For example, the first fluid guide 220 can assume an increasingly curved configuration along a direction extending from the first end 220a to the second end 220b. For example, a cross section of the first fluid guide 220 at the first end 220a along the lateral dimension can comprise a linear or substantially linear configuration. A cross section of the first fluid guide 220 at the second end 220b along the lateral dimension can comprise a segment of an oval.|0049| The first fluid guide 220 can comprise a first surface 222 oriented toward the first portion 214 of the frame 202, and a second surface 224 oriented away from the first portion 214 of the frame 202. In some instances, the increasing curvature along the longitudinal dimension can facilitate direction of fluid flowing over the first surface 222 toward the first portion 214 of the frame 202. In some instances, a convex portion of the second end 220b, including a portion of the convex curve closest to the frame 202, can be at a position between about 10% to about 90% of a distance between the longitudinal axis of the frame 202 and the frame 202, including about 20% to about 80%, about 40% to about 80%, and about 60% to about 80%. In some instances, a convex portion of the second end 220b, including a portion of the convex curve closest to the frame 202, can be at a position between about 25% to about 50% of a distance between the longitudinal axis of the frame 202 and the frame 202. In some instances, as described in further detail herein, a lateral cross section of the frame 202, such as a cross section along a plane perpendicular or substantially perpendicular to the longitudinal axis of the frame 202, can comprise a circular shape. The distance between the longitudinal axis of the frame 202 and the frame 202 can be a radius of the circle.

[0050] In some instances, the first and second sides 220c, 220d can be in the same plane. The plane can be parallel or substantially parallel to and / or extends along a plane that contains the diameter of the frame 202. In some instances, the first and second sides 220c,220d can be in a plane that contains the diameter of the frame 202, for example a plane bisecting the frame 202 along the longitudinal axis of the frame 202. Alternatively, the first and second sides 220c, 220d can be in a plane oriented at an angle relative to the plane containing the diameter of the frame 202. For example, the second corresponding portions of the frame 202, to which the second end 220b is coupled to, can be disposed laterally closer to the first portion 214 of the frame 202 than the first corresponding portions, to which the first end 220a is coupled to, along a lateral dimension of the frame 202.

[0051] In some instances, the first fluid guide 220 can comprise a first pliable sheet member 226. For example, the first pliable sheet member 226 can form the first fluid guide 220 such that respective edges of the first pliable sheet member 226 form the first and second ends 220a, 220b and first and second sides 220c, 220d of the first fluid guide 220. A first end 226a and second end 226b of the first pliable sheet member 226 can form the first and second ends 220a, 220b of the first fluid guide 220, respectively. A first and second side 226c, 226d of the first pliable sheet member 226 can form the first and second sides 220c, 220d of the first fluid guide 220, respectively. The first fluid flow portion can flow over a first surface 228 of the first pliable sheet member 226 oriented toward the first portion 214 of the frame 202. A second surface 230 of the first pliable sheet member 226 can oriented away from the first portion of the frame 202.

[0052] The first end 226a can be coupled to first corresponding portions of the frame 202, such as at or proximate to the first end 204 of the frame 202. The second end 226b can be coupled to the frame 202 at second corresponding portions of the frame 202 disposed distally relative to the first corresponding portions. In some instances, the first end 226a of the first pliable sheet member 226 can be coupled to opposing portions of the frame 202 at or proximate the first end 204 of the frame 202. The first pliable sheet member 226 can comprise an arcuate shape along a lateral dimension extending between opposing portions of the first and second sides 226c, 226d. In some instances, a cross section of the first pliable sheet member 226 along a lateral dimension can comprise a segment of an oval. For example, a cross section of the first pliable sheet member 226 along a plane perpendicular or substantially perpendicular to the longitudinal axis of the frame 202 can comprise a segment of an oval. In some instances, the first pliable sheet member 226 can assume an increasingly curved configuration along a distally extending direction. For example, a cross section at the first end 226a along the lateral dimension can comprise a linear or substantially linear configuration. A cross section at the second end 226b along the lateral dimension can comprise a segment of an oval. In some instances, the first and second sides 220c, 220d canbe in the same plane parallel or substantially parallel to and / or extends along a plane that contains the diameter of the frame 202. Alternatively, the first and second sides 220c, 220d can be in a plane oriented at an angle relative to the plane containing the diameter of the frame 202.

[0053] In some instances, the first fluid guide 220 can comprise a first and / or second flexible elongate rod 232, 234. In some instances, the first flexible elongate rod 232 can extend along at least a portion of the first end 220a of the first fluid guide 220, including an entire or substantially entire length of the first end 220a. For example, the first flexible elongate rod 232 can extend along at least a portion of the first end 226a of the first pliable sheet member 226, including an entire or substantially entire length of the first end 226a. Alternatively, the first fluid guide 220 may not have a first flexible elongate rod 232 extending along the first end 220a. In some instances, the second flexible elongate rod 234 can extend along at least a portion of the second end 220b of the first fluid guide 220, including an entire or substantially entire length of the second end 220b. For example, the second flexible elongate rod 234 can extend along at least a portion of the second end 226b of the first pliable sheet member 226, including an entire or substantially entire length of the second end 226b. The second flexible elongate rod 234 can assume an arcuate shape. In some instances, the first fluid guide 220 can comprise more flexible elongate rods disposed at other positions along its longitudinal dimension to provide structural strength, such as for the arcuate shape. In some instances, one or more flexible elongate rods can be coupled to and extend along respective lateral dimensions of the first pliable sheet member 226, such as to maintain the arcuate shape.

[0054] Figures 2D and 2E provide a perspective view and an end view, respectively, of the second fluid guide 240. As described herein, the second fluid guide 240 can be disposed in the fluid flow path and coupled to the frame 202 at a position distal of the first fluid guide 220. In some instances, the second fluid guide 240 can comprise a second pliable sheet member 246. In some instances, the second pliable sheet member 246 can have a shape of a parallelogram or substantially a parallelogram. One or more corners and / or edges of the second pliable sheet member 246 can be coupled to the frame 202 using any number of techniques, including sewing. For example, the second pliable sheet member 246 comprise first, second, third and fourth comers 246a, 246b, 246c, 246d. The second pliable sheet member 246 can have a first side 246e, a second side 246f, a third side 246g and a fourth side 246h. The first, second, third and fourth sides 246e, 246f, 246g, 246h can extend between respective corners 246a, 246b, 246c, 246d of the second pliable sheet member 246. In someinstances, a first comer of the parallelogram, such as the first corner 246a of the second pliable sheet member 246, can be configured to be coupled to the frame 202 at a first position. Second and fourth corners of the parallelogram, such as opposing corners, can be coupled to the frame 202. For example, the second and fourth corners 246b, 246d of the second pliable sheet member 246 can be coupled to the frame 202 at a second and third positions, the second and third positions being distal of the first position. In some instances, the second and third positions can be closer to a diameter of the frame 202 than the first position, including being disposed on the diameter of the frame 202. A third comer of the parallelogram, such as the third corner 246c of the second pliable sheet member 246 can be configured to be coupled to the frame 202 at a fourth position. The fourth position can be distally disposed from and further from the diameter of the frame 202 than the second and third positions. For example, the third corner 246c of the second pliable sheet member 246 can be further away from the longitudinal axis of the frame 202 such that a portion of the second pliable sheet member 246 folds back upon itself to provide a medial portion 252, such as at the fold, disposed closest to the diameter and / or longitudinal axis of the frame 202. For example, the medial portion 252 can extend between the second and fourth corners 246b, 246d of the second pliable sheet member 246. In some instances, the second fluid guide 240 can optionally comprise a tensioned member (not shown), such as a suture, extending along the medial portion 252, such as between the second and fourth corners 246b, 246d of the second pliable sheet member 246. The tensioned member can facilitate maintaining a shape of the second fluid guide 240, such as a curvature of the path provided by the second fluid guide 240.

[0055] The second pliable sheet member 246 can comprise a first surface 248 configured to be oriented toward the fluid flow path. A second surface 250 can be configured to be oriented away from the fluid flow path. At least a portion of the first surface 248 of the second pliable sheet member 246 between the first comer 246a, and second and fourth comers 246b, 246d can form a surface portion configured to direct the fluid flow away from the first portion of the frame 202. The first surface 248 between the first corner 246a, and second and fourth corners 246b, 246d can form a surface portion comprising one or more curved portions configured to guide and / or direct the first fluid flow portion away from the first portion 214 of the frame 202. In some instances, the curvature formed by the second pliable sheet member 246 for directing fluid flow can comprise an angle greater than 90°. Alternatively, the curvature formed by the second pliable sheet member 246 can comprise an angle of about 90°. The degree of curvature of the path formed by the second pliable sheetmember 246 can be selected to provide desired direction of fluid flow while reducing or avoiding stasis.

[0056] The third fluid guide 260 and the fourth fluid guide 280 can have an orientation that is rotated about the longitudinal axis of the frame 202 relative to that of the first fluid guide 220 and the second fluid guide 240, respectively. In some instances, the third fluid guide 260 and the fourth fluid guide 280 can have an opposing orientation about the longitudinal axis of the frame 202 relative to that of the first fluid guide 220 and the second fluid guide 240, respectively. In some instances, the opposing orientation can reduce or prevent retrograde flow through the lumen 212. In some instances, the third fluid guide 260 can comprise one or more features of the first fluid guide 220. In some instances, the third fluid guide 260 can have an opposing orientation relative to that of the first fluid guide 220 and have the same or similar features as the first fluid guide 220. In some instances, the fourth fluid guide 280 can comprise one or more features of the second fluid guide 240. In some instances, the fourth fluid guide 280 can have an opposing orientation relative to that of the second fluid guide 240 and have the same or similar features as the second fluid guide 240. Rotation of the orientation of the fluid guides can provide increased reduction in flow rate. Alternatively, the fluid guides can have the same or similar orientation. For example, the first and third fluid guides 220, 260 can have the same or similar orientation. The second and fourth fluid guides 240, 280 can have the same or similar orientation.

[0057] As described herein, in some instances, the flow rate reducer 200 can allow antegrade fluid flow therehthrough while reducing or preventing retrograde fluid flow therethrough. For example, one or more features of the fluid guides configured to direct fluid flow distally can be configured to reduce or prevent fluid flow in the opposite direction. In some instances, the opposingly oriented fluid guides can reduce or prevent antegrade fluid flow.

[0058] In some instances, the frame 202 can have a cylindrical configuration. In some instances, the frame 202 can assume a cylindrical shape. The frame 202 can comprise a hollow cylinder that defines an inner lumen for the fluid path. For example, the hollow cylinder can define the lumen 212 having the inlet opening 208 at the first end 204 and the outlet opening 210 at the second end 206 of the frame 202. As described herein, a lateral cross section of the frame 202 can have a circular or substantially circular shape. In some instances, the frame 202 can comprise a radially expandable wire frame. The frame 202 can comprise shape-memory material. For example, the frame 202 can assume the cylindrical configuration while in an expanded state. The frame 202 can assume a collapsed state duringdelivery to a target site. The collapsed state can have a diameter smaller than that of the expanded state. Alternatively, a frame can comprise a partial cylindrical configuration. In some instances, one or more portions of the frame 202 may not extend circumferentially around, including for example portions of the frame 202 not adjacent to and / or coupled to a fluid guide. For example, the frame can have a partial cylindrical configuration to provide a reduced profile for ease of transcatheter delivery. In some instances, the longitudinal portion of the frame 202 coupled to the first and second fluid guides 220, 240 can comprise a partial cylindrical configuration, for example comprising a partially circumferential frame portion having respective portions coupled to the first and second fluid guides 220, 240. The longitudinal portion of the frame 202 comprising the third and fourth fluid guides 260, 280 can comprise a partial cylindrical configuration, for example comprising a partially circumferential frame portion having respective portions coupled to the third and fourth fluid guides 260, 280. In some instances, a lateral cross section of the portion of the frame 202 coupled to the first and second fluid guides 220, 240, and the portion of the frame 202 coupled to the third and fourth fluid guides 260, 280, can each comprise a segment of a circle, including a semi-circle. In some instances, the pliable sheet members can comprise a material configured to be foldable such that the pliable sheet members can be folded for ease of transcatheter delivery, including a fabric and / or shape-memory material.

[0059] In some instances, the flow rate reducer 200 can optionally comprise a cover over at least a portion of the frame 202. In some instances, the flow rate reducer 200 does not include a cover over the frame 202. The flow rate reducer 200 can have the frame 202 deployed into the vasculature without any covers over portions thereof. In some instances, the flow rate reducer 200 can optionally comprise one or more anchors to facilitate maintaining its position at the target location. Alternatively, the flow rate reducer 200 may not include any anchors. For example, engagement between the frame 202 and one or more portions of the blood vessel wall can provide anchoring for the flow rate reducer 200.

[0060] A flow rate reducer can comprise more or fewer fluid guides. For example, the first and second fluid guides 220, 240 configured to direct fluid flow away and toward a longitudinal axis of the flow rate reducer to thereby generate turbulence in the fluid flow can form a first series, such as a first pair, of fluid guides. The third and fourth fluid guides 260, 280 can form a second series, such as a second pair, of fluid guides. A flow rate reducer can comprise one or more of the pairs of fluid guides to provide a target outflow rate. In some instances, each series, such as pair, of fluid guides can have an opposing orientation about the longitudinal axis of a flow rate reducer relative to an immediately preceding and / or proximalpair of fluid guides. In some instances, a series, such as pair, of fluid guides can have the same or opposite orientation about the longitudinal axis relative to the immediately preceding and / or proximal series of fluid guides.

[0061] Figures 3 A, 3B and 3C provide various views of an example of a flow rate reducer 300 comprising a fluid guide structure, arrangement and / or features that includes a plurality of distinct fluid guides arranged in series along a fluid flow path. Figure 3A is a side cross-sectional view of the flow rate reducer 300. Figures 3B and 3C are a perspective and end view, respectively, of a first fluid guide 320 of the flow rate reducer 300. Referring to Figure 3A, the flow rate reducer 300 can comprise a frame 302 at least partially defining a fluid flow path therethrough. The frame 302 can at least partially define a lumen 312 extending between an inlet opening 308 at a first end 304 and an outlet opening 310 at a second end 306 of the frame 302. The flow rate reducer 300 can comprise a first fluid guide 320, a second fluid guide 340, a third fluid guide 360, and a fourth fluid guide 380 disposed sequentially one after another along a direction extending from the first end 304 to the second end 306. In some instances, the fluid guides can be arranged in tandem within the frame 302, with or without overlapping end portions along a longitudinal dimension of the frame 302. For example, each fluid guide can be at least partially disposed in the fluid flow path and coupled to respective portions of the frame 302. In some instances, the first fluid guide 320 can have a planar configuration. The first fluid guide 320 can provide a planar ramp to direct a portion of the fluid flow flowing through the inlet opening 308 toward a first portion 314 of the frame 302.

[0062] Referring to Figures 3B and 3C, the first fluid guide 320 can comprise a first end 320a oriented toward the inlet opening 308 and a second end 320b oriented toward the outlet opening 310. In some instances, the first end 320a can be coupled to first corresponding portions of the frame 302, including at or proximate to the first end 304 of the frame 302. In some instances, the first end 320a can be coupled to opposing portions of the frame 302, for example extending along a diameter at or proximate to the inlet opening 308. The second end 320b can be coupled to the frame 302 at second corresponding portions disposed distally from the first corresponding portions. The first fluid guide 320 can comprise two sides 320c, 320d extending between respective ends of the first and second ends 320a, 320b. For example, the first end 320a and second end 320b, and the two sides 320c, 320d can form respective edges of the first fluid guide 320. In some instances, at least a portion of each of two sides 320c, 320d of the first fluid guide 320 can be coupled to the frame 302. The first end 320a and the second end 320b can be in a plane that is at an angle relative to a planecontaining a lateral dimension, such as diameter, of the frame 302. In some instances, the plane can be at an angle relative to a plane that bisects the frame 302 along a longitudinal axis. The longitudinal axis can extend between the first and second ends 304, 306 of the frame 302. The second end 320b of the first fluid guide 320 can be disposed further away from the plane containing the diameter of the frame 302 than the first end 320a to provide the ramp toward the first portion 314 of the frame 302. For example, the second end 320b can be at a position laterally closer to the first portion 314 of the frame 302 than the first end 320a. The second end 320b can be at a position between about 10% to about 90% of a distance between the longitudinal axis of the frame 302 and the frame 302, including about 20% to about 80%, about 40% to about 80%, and about 60% to about 80%. In some instances, the second end 320b can be at a position between about 25% to about 50% of a distance between the longitudinal axis of the frame 302 and the frame 302. Fluid flow having a forward flow direction flowing through the inlet opening 308 can flow past the first fluid guide 320 and be divided into first and second fluid flow portions. The first fluid guide 320 can have a first surface 322 oriented toward the first portion 314 of the frame 302, and a second surface 324 having an opposing orientation. The first fluid flow portion can flow over a first surface 322 of the first fluid guide 320 and be directed toward the first portion 314 of the frame 302. The second surface 324 of the first fluid guide 320 can be oriented toward the second fluid flow portion. The second fluid flow portion can flow distally past the first fluid guide 320. For example, the first fluid guide 320 may not alter and / or change a flow direction of the second fluid flow portion.

[0063] In some instances, the first fluid guide 320 can comprise a first pliable sheet member 326 configured to have a planar configuration. In some instances, the first pliable sheet member 326 can form or substantially form the first fluid guide 320. For example, a first surface 328 of the first pliable sheet member 326 can be oriented toward the first fluid flow portion. A second surface 330 of the first pliable sheet member 326 can be oriented toward the second fluid flow portion. The first pliable sheet member 326 can have a first end 326a coupled to the first corresponding portions of the frame 302. In some instances, the first end 326a can be at or proximate to the inlet opening 308, including coupled to opposing portions of the frame 302 at the inlet opening 308. A second end 326b can be coupled to the frame at the second corresponding portions of the frame 302. In some instances, the first pliable sheet member 326 can comprise a trapezoid or substantially trapezoid shape. In some instances, the first fluid guide 320 can optionally comprise a first flexible elongate rod 332 extending along at least a portion of the first end 326a of the firstpliable sheet member 326 and / or a second flexible elongate rod 334 extending along at least a portion of the second end 326b of the first pliable sheet member 326. For example, respective flexible elongate rods can extend along parallel or substantially parallel edges of a trapezoidshaped pliable sheet member. The flexible elongate rods 332, 334 can facilitate maintaining a shape of the first fluid guide 320, such as to facilitate directing the first fluid flow portion toward the first portion 314 of the frame 302. At least a portion of the first and second side 326c, 326d of the pliable sheet member 326, such as the sides forming the remaining sides of the trapezoid, can be coupled to the frame 302.

[0064] In some instances, the third fluid guide 360 can comprise one or more features of the first fluid guide 320. In some instances, the third fluid guide 360 can have the same or similar features as the first fluid guide 320. In some instances, the third fluid guide 360 can have an orientation that is opposite that of the first fluid guide 320. For example, the third fluid guide 360 can direct a portion of the fluid flow toward a second portion 316 of the frame 302. The first and second portions 314, 316 can be rotated about a longitudinal axis of the frame 302 relative to one another, including being at opposing positions around the longitudinal axis.

[0065] The flow rate reducer 300 can comprise one or more other features of the flow rate reducer 200 described with reference to Figures 2A through 2E. In some instances, remaining portions of the flow rate reducer 300 can have the same features as those of the flow rate reducer 200 described with reference to Figures 2A through 2E. For example, the second fluid guide 340 and the fourth fluid guide 380 can have the same features as the second and fourth fluid guides 240, 280 of the flow rate reducer 200 described with reference to Figures 2A through 2E. The second and fourth fluid guides 340, 380 can each comprise a pliable sheet member providing a portion configured to form a curved path that directs the fluid flow away from the first and second portions 314, 316 of the frame 302.

[0066] The fluid can flow through the inlet opening 308 at the first end 304 and flow past the first fluid guide 320, thereby dividing the fluid flow into a first and a second fluid flow portions. The first fluid flow portion can be directed toward the first portion 314 of the frame 302, while allowing the second fluid flow portion to flow distally. At least a portion of the second fluid guide 340 can be disposed at the first portion 314 of the frame 302 such that the first fluid flow portion can flow into the second fluid guide 340 and be directed away from the first portion 314 of the frame 302. The first fluid flow portion can subsequently be combined with the second fluid flow portion. The combined fluid flow can then be flowed past the third fluid guide 360 to divide the combined fluid flow into the two portions, a firstof the two fluid flow portions being directed by the third fluid guide 360 toward the second portion 316 of the frame 302. The second of the two fluid flow portions can continue to flow distally. At least a portion of the fourth fluid guide 380 can be disposed at the second portion 316 of the frame 302 such that the first of the two fluid flow portions can flow into the fourth fluid guide 380 and be directed away from the second portion 316 of the frame 302. The first of the two fluid flow portions can subsequently flow into the other fluid flow portion to provide a second combined fluid flow and the second combined fluid flow can then flow out of the outlet opening 310. Arrows in Figure 3A illustrate examples of the directions of fluid flow through the flow rate reducer 300.

[0067] In some instances, an implant assembly can comprise two or more flow rate reducers tandemly arranged. The two or more flow rate reducers can have similar or the same features. Alternatively, one or more of the plurality of flow rate reducers can have one or more features different from one or more of the other flow rate reducers. For example, a plurality of the same flow rate reducers can be arranged one after the other to provide desired reduction in fluid flow rate. Figure 4 provides a side view of an example of an implant assembly 400 comprising two flow rate reducers 402 in an end-to-end arrangement, one being positioned distally of the other. In some instances, the two flow rate reducers 402 can be aligned along one or both of their respective longitudinal axes. Each of the flow rate reducers 402 can comprise a frame 410 at least partially defining a corresponding portion of the fluid flow path. For example, each frame 410 can at least partially define a lumen 420 extending between an inlet opening 416 at a first end 412 of the frame 410 and an outlet opening 418 at a second end 414 of the frame 410.

[0068] Fluid flowing out of the outlet opening 418 of the first flow rate reducer 402, such as the flow rate reducer 402 more proximally disposed (on the left in Figure 4), can flow into the inlet opening 416 of the second flow rate reducer 402, such as the flow rate reducer 402 more distally disposed (on the right in Figure 4). The first frame 410 can at least partially define a first portion of the fluid flow path. The second frame 410 can at least partially define a second portion of the fluid flow path. Each of the flow rate reducers 402 can comprise a fluid guide structure, arrangement and / or feature that includes a plurality of distinct fluid guides in series along a fluid flow path. For example, each of the flow rate reducers 402 can comprise a first fluid guide 430, and a second fluid guide 450 disposed distally of the first fluid guide 430. In some instances, the flow rate reducers 402 can have one more features of the flow rate reducer 200 described with reference to Figures 2A through 2E. In some instances, the first and second fluid guides 430, 450 can have one ormore features of the first and second fluid guides 220, 240 described with reference to Figures 2A through 2E. For example, the first and second fluid guides 430, 450 can have the same features as those of the first and second fluid guides 220, 240, respectively, described with reference to Figures 2A through 2E. For example, each of the fluid guides 430, 450 can comprise a pliable sheet member. In some instances, each of the frames 410 can comprise an expandable frame, assuming a cylindrical shape in an expanded state. Alternatively, the first and second fluid guides 430, 450 can have one or more features of the first and second fluid guides 320, 340 described with reference to Figures 3A, 3B and 3C. In some instances, the first and second fluid guides 430, 450 can have the same features as the first and second fluid guides 320, 340. For example, the first fluid guides 430 can each comprise a pliable sheet member having a trapezoid or substantially trapezoid shape. The second fluid guides 450 can each comprise a pliable sheet member having a shape of a parallelogram or substantially a parallelogram.

[0069] In some instances, the two flow rate reducers 402 can be arranged such that the orientations are rotated around a longitudinal axis of one or both of the flow rate reducers 402 relative to one another. Figure 4 shows the two flow rate reducers 402 in opposing orientation relative to one another. The opposing orientation can reduce or prevent retrograde flow. In some instances, longitudinal axes of the first and second flow rate reducers 402 can be aligned, parallel and / or coaxial. For example, the first fluid guide 430 of the first flow rate reducer 402 can be at a position that is rotated about the longitudinal axis of the first frame 410 relative to that of the first fluid guide 430 of the second flow rate reducer 402, including having an opposing orientation. The second fluid guide 450 of the first flow rate reducer 402 can be at a position that is rotated about the longitudinal axis of the first frame 410 relative to that of the second fluid guide 450 of the second flow rate reducer 402, including having an opposing orientation. Alternatively, the first and second fluid flow reducers 402 can have the same orientation. For example, first and second fluid guides 430, 450 of each of the fluid flow reducers 402 can have the same orientation.

[0070] Fluid having a forward and / or distal flow direction and entering the inlet opening 416 of the first frame 410 can flow past the first fluid guide 430 of the first flow rate reducer 402. The first fluid guide 430 can thereby divide the fluid flow into a first and a second fluid flow portions. The first fluid guide 430 of the first flow rate reducer 402 can comprise a ramp to direct the first fluid flow portion toward a portion 422 of the first frame 410, while allowing the second fluid flow portion to flow distally. The second fluid guide 450 of the first flow rate reducer 402 can be in the first portion of the fluid flow path andcomprise at least a portion disposed at a position that is at or proximate to the portion 422 of the first frame 410. The second fluid guide 450 can comprise a curvature configured to direct the first portion of the fluid flow away from the portion 422 of the first frame 410. Flowing the first fluid flow portion past the second fluid guide 450 can provide a combined fluid flow comprising the first and second fluid flow portions. The combined fluid flow can exit through the outlet opening 418 of the first flow rate reducer 402 and into the inlet opening 416 of the second flow rate reducer 402.

[0071] In some instances, the second flow rate reducer 402 can provide further reduction in flow rate. In some instances, the second flow rate reducer 402 can repeat the reduction in fluid flow rate. The combined fluid flow can flow past the first fluid guide 430 of the second flow rate reducer 402, thereby dividing the combined fluid flow into the two portions. The first fluid guide 430 can provide a ramp configured to direct one of the two fluid flow portions toward a portion 422 of the frame 410 of the second flow rate reducer 402, while allowing the other of the two fluid flow portions to flow distally. The portion 422 of the second flow rate reducer 402 can be rotated about the longitudinal axis of the frame 410 of the first flow rate reducer 402 relative to the portion 422 of the second flow rate reducer 402, including having an opposing position about the longitudinal axis. The combined fluid flow can be divided by the first fluid guide 430 of the second flow rate reducer 402 into a third fluid flow portion and a fourth fluid flow portion. The third fluid flow portion can be directed toward the portion 422 of the frame 410 of the second flow rate reducer 402 while the fourth fluid flow portion can flow along a distally extending direction past the first fluid guide 430. The third fluid flow portion can flow to the second fluid guide 450 of the second flow rate reducer 402. The second fluid guide 450 of the second flow rate reducer 402 can comprise a curvature to direct the third fluid flow portion away from the portion 422 of the frame 410. The third fluid flow portion can subsequently flow into the fourth fluid flow portion after the third fluid flow portion is directed away from the portion 422 of the frame 410, thereby combining the two fluid flow portions. Fluid flowing out of the outlet opening 418 of the second flow rate reducer 402 can comprise the combined fluid flow after the third fluid flow portion flows into the fourth fluid flow portion.

[0072] In some instances, a second flow rate reducer can have different features from that of the first flow rate reducer. In some instances, an implant assembly can comprise a plurality of flow rate reducers, each flow rate reducer comprising a pair of fluid guides configured to direct fluid flow away from and then toward a longitudinal axis of the flow rate reducer. For example, the first flow rate reducer can comprise a first frame comprising a firstand second fluid guide. The first and second fluid guides can be configured to direct a fluid flow portion away from and toward a longitudinal axis of the first flow rate reducer, respectively. The second flow rate reducer can comprise a second frame comprising a third and fourth fluid guide. The third and fourth fluid guides can be configured to direct a fluid flow portion away from and toward a longitudinal axis of the second flow rate reducer, respectively. In some instances, the first and third fluid guides can be different. The first and third fluid guides can be rotated relative to one another around a longitudinal axis of the first frame or the second frame, and the second and fourth fluid guides being configured to be rotated relative to one another around the longitudinal axis of the first frame or the second frame. The first and third fluid guides can be opposingly oriented relative to one another around the longitudinal axis of the first frame or the second frame. In some instances, the second and fourth fluid guides can be opposingly oriented relative to one another around the longitudinal axis of the first frame or the second frame. In some instances, the first and second flow rate reducers can comprise a different number of fluid guides.

[0073] Flowing a fluid past through one or more flow rate reducers described herein can slow the fluid flow rate, including a forward flow velocity. For example, flowing the fluid past the plurality of fluid guides of a flow rate reducer can slow the flow rate. In some instances, flow rate at the outlet opening of a flow rate reducer, such as an outlet flow rate, can be between about 10% and about 90% that of a flow rate at an inlet opening of the flow rate reducer, such as an inlet flow rate, including about 40% to about 90%, about 50% to about 90%, about 60% to about 90%, and about 80% to about 90%. As described herein, in some instances multiple flow rate reducers can be arranged in tandem to achieve an outlet flow rate. For example, flow rate at the outlet opening of a last flow rate reducer, such as an outlet flow rate, can be between about 10% and about 90% of flow rate at an inlet opening of a first flow rate reducer, such as an inlet flow rate, including about 40% to about 90%, about 50% to about 90%, about 60% to about 90%, and about 80% to about 90%. The first flow rate reducer can be a most proximally disposed flow rate reducer. The last flow rate reducer can be a most distally disposed flow rate reducer. In some instances, flow rate, such as forward flow velocity, reduction provided by the flow rate reducers can depend on a forward flow velocity at an inlet, providing increased reduction with increased inlet forward flow velocity.

[0074] As described herein, one or more flow rate reducers described herein can be configured, such as sized and / or shaped, for deployment to a target location in the venous vasculature. In some instances, a flow rate reducer can have a length of about 50 millimeters(mm) to about 300 millimeters (mm), including about 100 millimeters (mm) to about 250 millimeters (mm), and about 200 millimeters (mm) to about 250 millimeters (mm). In some instances, a flow rate reducer can have a width, such as a diameter, of about 10 millimeters (mm) to about 200 millimeters (mm), including about 50 millimeters (mm) to about 150 millimeters (mm), and about 50 millimeters (mm) to about 100 millimeters (mm).

[0075] Figure 5 is a process flow diagram showing an example of a process 500 for reducing a fluid flow rate. In block 502, the process can involve providing a flow rate reducer. The flow rate reducer can comprise one or more features of one or more of the flow rate reducers described herein, including for example flow rate reducer 200 described with reference to Figures 2A to 2E, flow rate reducer 300 described with reference to Figures 3A to 3C, and / or flow rate reducer 402 described with reference to Figure 4. In some instances, providing the flow rate reducer can comprise providing a frame at least partially defining a fluid flow path through the frame from an inlet opening to an outlet opening. For example, the frame can at least partially define a lumen extending between the inlet and outlet openings. In some instances, providing the flow rate reducer can comprise providing a first and second fluid guide configured to be in the fluid flow path, for example disposed within the lumen, and coupled to the frame. The second fluid guide can be disposed distally of the first fluid guide.

[0076] In block 504, the process can involve flowing, passing and / or injecting a fluid flow into the inlet opening of the flow rate reducer at an inlet flow rate. In block 506, the process can involve flowing, passing and / or injecting the fluid flow past the first fluid guide to divide the fluid flow into a first fluid flow portion and a second fluid flow portion. Flowing the fluid flow past the first fluid guide can direct the first fluid flow portion toward a first portion of the frame and allow the second fluid flow portion to flow distally. In block 508, the process can involve flowing, passing and / or injecting the first fluid flow portion past the second fluid guide to direct the first fluid flow portion away from the first portion of the frame. Flowing the first fluid flow portion past the first fluid guide can comprise directing the first fluid flow portion toward the second fluid guide. After the first fluid flow portion is directed away from the first portion of the frame, the first fluid flow portion can flow into the second fluid flow portion to provide a combined fluid flow. In block 510, the process can involve flowing, passing and / or injecting the fluid flow out of the outlet opening at an outlet flow rate that is less than the inlet flow rate. The forward flow velocity at the outlet opening can be less than that at the inlet opening. For example, the combined fluid flow can flow out of the outlet opening at a reduced forward flow rate.

[0077] In some instances, flowing the fluid flow past the first fluid guide can comprise splitting the inlet flow into two equal or substantially equal fluid flow portions. For example, half of the inlet flow flows can be directed by the first fluid guide toward the first portion of the frame. The other half of the inlet flow can be allowed to flow along a distally extending direction. In some instances, flowing the fluid flow past the first fluid guide can comprise allowing the second fluid flow portion to flow along a direction parallel or substantially parallel to a longitudinal axis of the frame. Flowing the first fluid flow portion into the second fluid flow portion can comprise generating turbulent fluid flow, thereby slowing the forward flow rate. For example, the combined fluid flow can comprise turbulent fluid flow.

[0078] In some instances, the process can involve flowing the combined fluid flow past a third fluid guide in the fluid flow path distal of the second fluid guide to divide the combined fluid flow into a two fluid flow portions. In some instances, flowing the combined fluid flow past a third fluid guide can comprise directing the one of the two fluid flow portions toward a second portion having an orientation rotated about the longitudinal axis of the frame relative to that of the first portion of the frame, including an opposite orientation. The third fluid guide can direct one of the two fluid flow portions toward the second portion of the frame and allow the second of the two fluid flow portions to flow distally. The process can involve flowing the first of the two fluid flow portions past a fourth fluid guide to direct the first of the two fluid flow portions away from the second portion of the frame and into the second of the two fluid flow portions, such as recombining the two fluid flow portions. For example, flowing the combined fluid flow past the third fluid guide can comprise directing the one of the two fluid flow portions toward the fourth fluid guide. The recombined fluid flow portions can have a forward flow velocity less than that of the combined fluid flow portion. In some instances, flowing the combined fluid flow past the third fluid guide and fourth fluid guide can comprise flowing the combined fluid flow past a third fluid guide and a fourth fluid guide of the same fluid flow reducer comprising the first and second fluid guides. For example, flowing the fluid flow out of the outlet opening can comprise flowing the recombined fluid flow portions out of the outlet opening of the fluid flow reducer comprising the first, second, third and fourth fluid guides.

[0079] In some instances, flowing the fluid flow out of the outlet opening at the outlet flow rate comprises flowing the fluid flow out of the outlet opening at a flow rate that is between about 10% and about 90% of the inlet flow rate, including about 40% to about 90%, about 50% to about 90%, about 60% to about 90%, and about 80% to about 90% of theinlet flow rate. In some instances, the process can involve flowing the fluid flow past more than four fluid guides to provide an outlet flow rate, including six or eight fluid guides. For example, the frame can comprise more than four fluid guides disposed in the fluid flow path. In some instances, the process can involve flowing the fluid flow past fewer than four fluid guides to provide the outlet flow rate, such as fluid guides. For example, two fluid guides can be disposed in the fluid flow path and coupled to the frame.

[0080] In some instances, the process can comprise deploying the flow rate reducer into a location in the venous system. In some instances, the process can comprise deploying the flow rate reducer into a location in an inferior vena cava (IVC), superior vena cava (SVC), or portal vein. In some instances, deploying the flow rate reducer into the venous system, such as the inferior vena cava (IVC), superior vena cava (SVC), or portal vein, can comprise advancing the flow rate reducer in a collapsed state into the venous system, such as the inferior vena cava (IVC), superior vena cava (SVC), or portal vein. In some instances, the flow rate reducer can be expanded to assume an expanded state after the flow rate reducer is positioned at or proximate to a target site within the venous system within the inferior vena cava (IVC), superior vena cava (SVC), or portal vein. For example, the flow rate reducer can be expanded to assume the expanded state after the flow rate reducer is at or proximate to a target site in the inferior vena cava (IVC), superior vena cava (SVC), or portal vein.

[0081] In some instances, providing the frame can comprise providing an expandable frame, such as a radially expandable frame. In some instances, providing the first fluid guide can comprise providing a first pliable sheet member. In some instances, providing the second fluid guide can comprise providing a second pliable sheet member. In some instances, providing the third fluid guide and / or fourth fluid guide can comprise providing a third pliable sheet member and / or fourth pliable sheet member, respectively. The frame can assume a configuration having a smaller lateral dimension, such as diameter, in the collapsed state than in the expanded state. Providing the frame can comprise providing an expandable frame configured to assume a collapsed state while being advanced along at least a portion of the delivery pathway. The first and / or second fluid guides can assume a folded configuration while being advanced along at least a portion of the delivery pathway. For example, expanding the flow rate reducer can comprise expanding the expandable frame and unfolding the first fluid guide, the second fluid guide, third fluid guide, and / or fourth fluid guide. The first, second, third and / or fourth pliable sheet members can be unfolded while the flow rate reducer is in the expanded state.

[0082] As described herein, in some instances, more than one flow rate reducer can be used. In some instances, the process can involve flowing the fluid flow through a plurality of flow rate reducers arranged in tandem. In some instances, the process can comprise providing a first flow rate reducer comprising a first and second fluid guide, and providing a second flow rate reducer comprising a third and a fourth fluid guide. Providing the first flow rate reducer can comprise providing a first frame at least partially defining a first fluid flow path through the first frame from a first inlet opening to a first outlet opening. The first and second fluid guides can be in the first fluid flow path and coupled to the first frame, the second fluid guide being distal of the first fluid guide. Providing the second flow rate reducer can comprise providing a second frame at least partially defining a second fluid flow path through the second frame from a second inlet opening to a second outlet opening. The third and fourth fluid guides can be in the second fluid flow path and coupled to the second frame, the fourth fluid guide being distal of the third fluid guide. The process can involve flowing an outlet flow from the first outlet opening into the second inlet opening. In some instances, the process can comprise flowing the combined fluid flow into the second inlet opening of the second flow rate reducer at a second inlet flow rate. The combined fluid flow can be flowed past the third fluid guide to divide the combined fluid flow into two fluid flow portions. Flowing the combined fluid flow past the third fluid guide can comprise directing a first of the two fluid flow portions toward a portion of the second frame while allowing a second of the two fluid flow portions to flow distally. The first of the two fluid flow portions can subsequently flow past the fourth fluid guide to direct the first of the two fluid flow portions away from the portion of the second frame and into the second of the two fluid flow portions.

[0083] In some instances, the inlet flow rate can be an inlet flow rate of a first of a plurality of flow rate reducers arranged in tandem. The outlet flow rate can be an outlet flow rate of a last of the plurality of flow rate reducers. For example, flowing the fluid flow out of the second outlet opening can comprise flowing a flow rate that is between about 10% and about 90% of the inlet flow rate at the first inlet opening, including about 40% to about 90%, about 50% to about 90%, about 60% to about 90%, and about 80% to about 90% of the inlet flow rate at the first inlet opening. In some instances, the process can involve flowing the fluid flow past more than two flow rate reducers. For example, each flow rate reducer can be formed using a first and second fluid guide. In some instances, one or more of the flow rate reducers can have more than two fluid guides, such as including a third and fourth fluid guide.

[0084] Figure 6A is a perspective view of a flow rate reducer 600 comprising a fluid guide structure, arrangement and / or feature that includes a truncated conical fluid guide 620. Figures 6B and 6C are end views of the truncated conical fluid guide 620 in a first state and a second state, respectively. Referring to Figure 6A, the fluid rate reducer 600 can comprise a frame 602. The frame 602 can comprise an inlet opening 608 and an outlet opening 610. For example, the inlet opening 608 can be at a first end 604 of the frame 602. The outlet opening 610 can be at a second end 606 of the frame 602. The frame 602 can at least partially define a lumen 612, such as from the inlet opening 608 to the outlet opening 610, to provide a fluid flow path extending therethrough. The truncated conical fluid guide 620 can comprise a first end 622 and a second end 624. The first end 622, such as a smaller of the two ends, can be oriented toward the inlet opening 608 of the frame 602. The second end 624 can be oriented toward the outlet opening 610. The second end 624 can be coupled to respective portions of the frame 602. In some instances, the second end 624 can extend circumferentially around the lumen 612, for example being coupled to a circumferential portion of the frame 602. A first opening 626 can be at the first end 622 and a second opening 628 can be at the second end 624. The truncated conical fluid guide 620 can be at least partially disposed in the lumen 612 such that the first and second openings 626, 628 are aligned with the fluid flow path. For example, the first and second openings 626, 628 can be aligned and / or coaxial with a longitudinal axis of the frame 602 extending between the first and second ends 604, 606. Blood can flow into the lumen 612 through the inlet opening 608 and push against the truncated conical fluid guide 620, such as a first surface 640 of the truncated conical fluid guide 620, causing the truncated conical fluid guide 620 to reversibly fold down toward the outlet opening 610 and thereby reducing a size of the first opening 626. A second surface 642, for example opposing surface, of the truncated conical fluid guide 620 can be pushed toward the second end 606 of the frame 602. Reducing the size of the first opening 626 can reduce and / or slow fluid flow through the first opening 626, providing a reduced flow rate at the outlet opening 610 as compared to the flow rate at the inlet opening 608. In some instances, the fluid flow reducer 600 can provide a larger reduction in the outlet flow rate for faster inlet flow rate, for example providing a greater reduction in flow rate the higher the incident flow rate.

[0085] In some instances, the truncated conical fluid guide 620 can comprise a flexible membrane 630 assuming a truncated conical shape or a substantially truncated conical shape. In some instances, a unitary and / or integral flexible membrane forms the truncated conical or substantially truncated conical shape. The flexible membrane 630 cancomprise a polymeric and / or elastomeric material that is impermeable to blood. In some instances, the flexible membrane 630 can extend circumferentially around the lumen 612. The first end 622 of the truncated conical fluid guide 620 can comprise a first end 632 of the flexible membrane 630. In some instances, the first end 632 of the flexible membrane 630 can form the first end 622 of the truncated conical fluid guide 620. The second end 624 of the truncated conical fluid guide 620 can comprise a second end 634 of the flexible membrane 630. In some instances, the second end 634 of the flexible membrane 630 can form the second end 624 of the truncated conical fluid guide 620. For example, the first end 632 of the flexible membrane 630 can define the first opening 626. The second end 634 of the flexible membrane 630 can define the second opening 628. In some instances, the second end 634 of the flexible membrane 630 can be coupled to respective portions of the frame 602, including portions around a circumference of the frame 602. Blood can flow into the lumen 612 through the inlet opening 608 and push against the flexible membrane 630, causing the flexible membrane 630 to fold down toward the second end 634 and thereby reducing a size of the first opening 626 and slowing a forward flow velocity of the blood.|0086| In some instances, the truncated conical fluid guide 620 can comprise one or more flexible, bendable and / or deformable members to provide structural support and / or reinforcement for the flexible membrane 630. In some instances, the truncated conical fluid guide 620 can comprise a circumferential member coupled to and extending along and / or adjacent to the second end 634 of the flexible membrane 630. In some instances, the truncated conical fluid guide 620 can comprise a plurality of circumferential members extending around and coupled to respective circumferential portions of the flexible membrane 630. In addition, or in the alternative, the truncated conical fluid guide 620 can comprise a plurality of elongate rods extending along and coupled to respective longitudinal portions of the flexible membrane 630, such as between the first and second ends 632, 634.

[0087] Figures 6B and 6C show the truncated conical fluid guide 620 in a first state and a second state, the second state providing a larger fluid flow rate reduction than does the first state. Referring to Figure 6B, the flexible membrane 630 can comprise a first surface 636 and a second surface 638. In some instances, the first surface 636 can be oriented toward the inlet opening 608 of the frame 602. The second surface 638 of the flexible membrane 630 can be oriented away from the inlet opening 608, for example toward the outlet opening 610. Blood flowing through the inlet opening 608 can push against the first surface 636, causing the flexible membrane 630 toward the outlet opening 610 and to fold onto itself. For example, the blood flow can press against the first surface 636 to push thefirst end 632 of the flexible membrane 630 toward the second end 634 of the flexible membrane 630, causing the flexible membrane 630 to fold inward toward the longitudinal axis of the frame 602. In some instances, Figure 6C shows the truncated conical fluid guide 620 in a state in which a higher volume of blood and / or blood having a higher flow rate is flowing through the inlet opening 608. Higher volume and / or forward flow velocity can provide increased force exerted upon the flexible membrane 630, thereby causing further folding of the flexible membrane 630. Folding of the flexible membrane 630 can cause a reduction in size of the first opening 626 to thereby increase restriction in the blood flow and pressure difference across the truncated conical fluid guide 620, and provide a slower flow rate at the outlet opening 610. For example, the flow rate at the outlet opening 610 can depend on a flow rate at the inlet opening 608, the flow rate reducer 600 providing a larger decrease in flow rate with faster inlet flow rate. In some instances, Figure 6B shows the truncated conical fluid guide 620 in a state with blood flowing therethrough during at least a portion of less exertion, such as while a patient is at rest. In some instances, Figure 6C shows the truncated conical fluid guide 620 in a state with blood flowing therethrough during at least a portion of increased exertion, such as while a patient is doing exercise. Figure 6B shows that the flexible membrane 630 can comprise a plurality of folds along a longitudinal dimension in the first state. For example, the first opening 626 can have a non-circular shape. Alternatively, the flexible membrane 630 may not have any folds along the longitudinal dimension in the first state. For example, the first opening 626 can have a circular or substantially circular shape in the first state.

[0088] In some instances, the truncated conical fluid guide 620 can optionally comprise one or more openings and / or slits extending along respective portions around a circumference thereof. The openings and / or slits can prevent or reduce blood flow stasis and thrombogenesis. For example, the flexible membrane 630 can comprise a plurality of openings and / or slits 650 extending through a thickness of the flexible membrane 630. Each opening and / or slit 650 can be along respective portions of a circumference of the truncated conical fluid guide 620. In some instances, the openings and / or slits 650 can be along a circumferential portion at or proximate to the second end 634 of the flexible membrane 630.

[0089] The truncated conical fluid guide 620 can form an acute angle with a portion of the frame 602 on an inlet side of the truncated conical fluid guide 620, such as a portion of the frame 602 that is between the first end 604 and portions coupled to the truncated conical fluid guide 620. For example, respective portions of the flexible membrane 630, such as while the flexible membrane 630 is in a first state as described herein, and theframe 602 can form an angle of about 5 degrees (°) to about 15 degrees (°), including about 5 degrees (°) to about 10 degrees (°), and about 5 degrees (°). As described herein, the flexible membrane 630 can reversibly fold onto itself in response to pressure applied by blood flow. The flexible membrane 630 can move away from the frame 602 in response to pressure from the blood flow. For example, while in the folded configuration, such as a second state as described herein, the flexible membrane 630 and the frame 602 can form an angle of about 40 degrees (°) to about 60 degrees (°), including about 40 degrees (°) to about 50 degrees (°), and about 45 degrees (°). In some instances, the first opening 626, while the flexible membrane 630 is in the folded configuration, can have a diameter no less than about 50% that of the frame 602, including between about 50% and about 80% of a diameter of the frame 602, and between about 50% and about 60%. The diameter of the first opening 628 while the flexible member 630 is in the folded configuration can be selected to provide desired reduction in blood flow rate while preventing overreduction in the flow rate.

[0090] Figure 7 A is a perspective view of a flow rate reducer 700 comprising a structure, arrangement and / or feature that includes truncated conical fluid guide 720 having a plurality of leaflets 730. Figures 7B and 7C are end views, of the truncated conical fluid guide 720 in a first state and a second state, respectively. The flow rate reducer 700 can comprise a frame 702 at least partially defining a lumen 712 through which blood flow can pass. Blood can flow into the lumen 712 through an inlet opening 708 at a first end 704 of the frame 702 and out of the lumen 712 through an outlet opening 710 at a second end 706 of the frame 702. The plurality of leaflets 730 can be arranged circumferentially around a portion of the lumen 712. Each of the leaflets 730 can be arranged at an angle relative to the frame 702 where a first edge 730a of the leaflet 730 is disposed closer to the inlet opening 708 than a second edge 730b, for example, such that the leaflets 730 at least partially form a truncated conical or substantially truncated conical shape. In some instances, the flow rate reducer 700 can comprise four leaflets 730. For example, the second edge 730b can be configured to be coupled to the frame 702. The first edge 730a can be oriented away from the frame 702 and toward a longitudinal axis of the frame 702. The longitudinal axis can extend between the two ends 704, 706 of the frame 702. The first edge 730a can have a length shorter than that of the second edge 730b. The first edge 730a can be disposed within the flow path and partially define a first opening 722 that allows blood flow to pass through. In some instances, the second edges 730b can at least partially define a second opening 724 disposed closer to the outlet opening 710 than the first opening 722. In some instances, the leaflets 730 can be sized and / or arranged such that a gap and / or space remains between adjacent leaflets 730. Forexample, each leaflet 730 can comprise a third edge 730c and a fourth edge 730d extending between respective ends of the first and second edges 730a, 730b. In some instances, each leaflet 730 can have a trapezoidal or substantially trapezoidal shape. In some instances, a third edge 730c of a leaflet 730 can be spaced from a fourth edge 730d of an adjacent and / or immediately neighboring leaflet 730.

[0091] Figures 7B and 7C show the truncated conical fluid guide 720 in a first state and a second state, the second state providing more fluid flow rate reduction than does the first state. Referring to Figure 7B, the plurality of leaflets 730 can be arranged circumferentially around the lumen 712 such that the first edges 730a of the leaflets 730 can partially define the first opening 722. Blood flow through the lumen 712 from the inlet opening 708 to the outlet opening 710 can press upon a first surface 732 of the leaflets 730 and cause the leaflets 730 to reversibly move toward the outlet opening 710, for example moving a second opposing surface 734 of the leaflets 730 toward the outlet opening 710. In response to pressure exerted upon a first surface 732 of the leaflets 730, the leaflets 730 can move closer to one another to thereby reduce a size of the first opening 722 and / or move the first edges 730a closer to one another. The size of the first opening 722 and distance, space and / or gap between adjacent leaflets 730 of the state shown in Figure 7C are smaller than those of the state shown in Figure 7B. The smaller first opening 722 and / or reduced distance, space and / or gap between adjacent leaflets 730 can further reduce forward flow rate of the blood. The first opening 722 and / or distance, space and / or gap between adjacent leaflets 730 can remain during increased flow rate conditions. Alternatively, the distance, space and / or gap between adjacent leaflets 730 can close during increased flow rate conditions, allowing adjacent leaflets 730 to be in contact. In some instances, Figure 7B shows the truncated conical fluid guide 720 in a state with blood flowing therethrough during at least a portion of less exertion, such as rest. In some instances, Figure 7C shows the truncated conical fluid guide 720 in a state with blood flowing therethrough during at least a portion of increased exertion, such as exercise.

[0092] In some instances, each leaflet 730 can comprise a flexible membrane 740 configured to move and / or fold in response to pressure exerted by blood flow passing through the lumen 712. For example, a respective flexible membrane 740 can form or substantially form each leaflet 730. A first edge 740a, for example having a shorter length than that of the second edge 740b, of the flexible membrane 740 can be oriented toward the longitudinal axis of the frame 702 and disposed within the flow path. A second edge 740b of the flexible membrane 740 can be configured to be coupled to the frame 702. The first edge 740a canpartially define the first opening 722. Respective portions of the second edge 740b can define the second opening 724. A third and fourth edge 740c, 740d can extend between respective ends of the first and second edges 740a, 740b, such as to form a trapezoidal or substantially trapezoidal shape. A first surface of the flexible membrane 740 can be oriented toward the inlet opening 708 and a second opposing surface 744 of the flexible membrane 740 can be oriented toward the outlet opening 710. In response to pressure exerted upon the first surface 742, the flexible membrane 740 can move toward the outlet opening 710. Adjacent flexible membranes 740 can move closer to each other to thereby reduce a size of the first opening 722 and / or reduce a distance, space and / or gap between adjacent third and fourth edges 740c, 740d.

[0093] In some instances, the truncated conical fluid guide 720 can optionally comprise an openings and / or slit extending along a respective lateral portion of each leaflet 730. The openings and / or slits can prevent or reduce blood flow stasis and thrombogenesis. For example, each flexible membrane 740 can comprise an openings and / or slit 750 extending through a thickness of the flexible membrane 740. Each opening and / or slit 750 can be along respective lateral portion of the flexible membrane 740. In some instances, the openings and / or slits 750 can be along a lateral portion at or proximate to the second edge 740b of the flexible membrane 740.

[0094] The flow rate reducer 700 can have one or more other features of the flow rate reducer 600 described with reference to Figures 6A through 6C. For example, the flow rate reducer 700 can comprise one or more flexible, bendable and / or deformable members to provide structural support and / or reinforcement for each of the leaflets 730.

[0095] In some alternative instances, a fluid flow reducer can comprise a conical fluid guide comprising a plurality of leaflets circumferentially disposed around a lumen of a frame. The plurality of leaflets can be coupled to respective portions of the frame around a circumference of the frame. The plurality of leaflets can each comprise a pointed end portion disposed at or adjacent to a center of the lumen on a longitudinal axis of the frame, such as shown in dashed lines in Figures 7A, 7B and 7C. For example, each of the plurality of leaflets can have a triangular or substantially triangular shape. In some instances, each of the plurality of leaflets can have one or more other features of the leaflets 730 described with reference to Figures 7 A, 7B and 7C.

[0096] Figures 8A and 8B show side views of a flow rate reducer 800 comprising a fluid guide structure, arrangement and / or feature that includes a plunger fluid guide 820. The flow rate reducer 800 can comprise a frame 802 at least partially defining a lumen 812through which blood flow can pass. Blood can flow into the lumen 812 through an inlet opening 808 at a first end 804 of the frame 802 and out of the lumen 812 through an outlet opening 810 at a second end 806 of the frame 802. The frame 802 can comprise a portion that curves inward toward a longitudinal axis of the frame 802. The longitudinal axis can extend between the first and second ends 804, 806 of the frame 802. In some instances, a circumferential portion of the frame 802 can curve inward toward the longitudinal axis of the frame 802. For example, the frame 802 can comprise a narrowed portion 814 that forms a neck along the frame 802. In some instances, portions of the frame 802 on an inlet side, such as between the first end 804 and the narrowed portion 814, can have a same or similar diameter as portions of the frame 802 on an outlet side, such as between the narrowed portion 814 and the second end 806. The plunger fluid guide 820 can be at least partially disposed in the lumen 812 of the inlet side. Movement of the plunger fluid guide 820 toward the narrowed portion 814 can reduce fluid flow rate through the fluid flow reducer 800.

[0097] The plunger fluid guide 820 can be disposed in a portion of the lumen 812 that is on an inlet side of the narrowed portion 814. For example, the plunger fluid guide 820 can be disposed between a narrowest portion 816 of the narrowed portion 814 and the inlet opening 808 such that movement of the plunger fluid guide 820 toward the narrowed portion 814 can result in reduction in a distance between the plunger fluid guide 820 and the frame 802 to provide the reduced flow rate. In some instances, the narrowest portion 816 can have a diameter no less than about 50% that of the widest portion of frame 802, including between about 50% and about 80%, and between about 50% and about 60%. The plunger fluid guide 820 can have a first end portion 822 configured to be oriented toward the first end 804 and a second end portion 824, such as an opposing end portion, configured to be oriented toward the second end 806. Each of the first and second end portions 822, 824 can comprise curved surface portions 826, 828 having differing degrees of curvature. In some instances, the respective curved surface portions of the first and second end portions 822, 824 can have different radii of curvature. For example, the first curved surface portion 826 of the first end portion 822 can have a smaller radius of curvature than that of the second curved surface portion 828 of the second end portion 824. In some instances, the plunger fluid guide 820 can have a teardrop or substantially teardrop shape. In some instances, the plunger fluid guide 820 can have a shape that is symmetric around a longitudinal axis of the plunger fluid guide 820. The longitudinal axis of the plunger fluid guide 820 can extend between the first and second end portions 822, 824 of the plunger fluid guide 820. A more rounded portion of the teardrop shape can be oriented toward the second end 806. In some instances, the plungerfluid guide 820 can have a fineness ratio (i.e. length to maximum diameter) of about 4 to about 6, including about 4 to about 5, including about 4.5. In some instances, the plunger fluid guide 820 can comprise a non-cambered and / or axially symmetric shape having same as or similar features as National Advisory Committee for Aeronautics (NACA) 0000-series airfoils. The orientation and / or shape of the plunger fluid guide 820 can be selected to provide desired flow pattern through the lumen 812. In some instances, the plunger fluid guide 820 can be centered in the lumen 812. For example, the longitudinal axis of the plunger fluid guide 820 can be coaxial and / or aligned with the longitudinal axis of the frame 802.

[0098] As described in further detail herein, the plunger fluid guide 820 can move toward the narrowed portion 814 of the frame 802 in response to pressure exerted thereupon by blood flowing past it. In some instances, the fluid flow reducer 800 can comprise a spring, strut and / or other elastic, flexible and / or deformable member to allow the plunger fluid guide 820 to reversibly move toward the narrowed portion 814 of the frame 802. Referring to Figure 8A, in some instances, the fluid flow reducer 800 can comprise a spring 830 (e.g., linear spring, blunter linear spring) coupling the second end portion 824 and a support structure 840 at least partially disposed in the lumen 812. For example, a first end portion 832 of the spring 830 can be oriented toward and coupled to the second end portion 824 of the plunger fluid guide 820. In some instances, the spring 830 can be coupled to a center portion of the second end portion 824. A second end portion 834 of the spring 830 can be oriented toward and coupled to the support structure 840 having respective ends 842, 844 coupled to the frame 802. In some instances, the support structure 840 can comprise an elongate rod member extending across a diameter of the lumen 812.

[0099] In addition, or in the alternative, in some instances, the fluid flow reducer 800 can comprise a plurality of flexible and / or deformable elongate members 850 configured to couple the plunger fluid guide 820 to respective portions of the frame 802. In some instances, the plurality of flexible and / or deformable elongate members 850 can comprise respective ends 852, 854 configured to couple the second end portion 824 of the plunger fluid guide 820 to respective portions of the frame 802, including respective portions of the narrowed portion 814. For example, the fluid flow reducer 800 can comprise three flexible and / or deformable elongate members 850 evenly distributed around the circumference of the frame 802. The plurality of flexible and / or deformable elongate members 850 can reversibly fold, bend and / or deform to allow the plunger fluid guide 820 to move back and forth within the lumen 812.

[0100] Figures 8A and 8B show the plunger fluid guide 820 in a first state and a second state, respectively, the second state providing more fluid flow rate reduction than does the first state. Blood flowing through the inlet opening 808 can exert pressure upon the plunger fluid guide 820, such as the first end portion 822 of the plunger fluid guide 820, thereby moving the plunger fluid guide 820 toward the narrowed portion 814 of the frame 802. Figure 8B shows the plunger fluid guide 820 disposed closer to the narrowed portion 814 of the frame 802 than that shown in Figure 8A. The spring 830 and / or plurality of flexible and / or deformable elongate members 850 can reversibly move the plunger fluid guide 820 toward and away from the narrowed portion 814, such as forward and backward, within the lumen 812. Moving the plunger fluid guide 820 closer to the narrowed portion 814 can further reduce flow rate through the frame 802. A space, distance and / or gap is maintained between the frame 802 and the plunger fluid guide 820 in the second state, such as between the narrowed portion 814 of the frame 802 and the second end portion 824 of the plunger fluid guide 820. In some instances, Figure 8 A shows the plunger fluid guide 820 in a state with blood flowing therethrough during at least a portion of less exertion, such as rest. In some instances, Figure 8B shows the plunger fluid guide 820 in a state with blood flowing therethrough during at least a portion of increased exertion, such as exercise.

[0101] Figure 9 is a side view of a flow rate reducer 900 comprising a fluid guide structure, arrangement and / or feature that includes a plunger fluid guide 920 having an orientation opposite that described with reference to Figures 8 A and 8B. For example, the plunger fluid guide 920 can have a teardrop or substantially teardrop shape with an orientation that is opposite that described with reference to the plunger fluid guide 820 of Figures 8A and 8B. The flow rate reducer 900 can comprise a frame 902 at least partially defining a lumen 912 through which blood flow can pass, the lumen 912 extending between an inlet opening 908 at a first end 904 of the frame 902 and an outlet opening 910 at a second end 906 of the frame 902. The frame 902 can comprise a narrowed portion 914, including a narrowest portion 916, that curves inward toward a longitudinal axis of the frame 902. The plunger fluid guide 920 can have a first end portion 922 having a first curved surface portion 926 that is more rounded than a second curved surface portion 928 of a second end portion 924. The first end portion 922 can be configured to be oriented toward the first end 904 of the frame 902 and the second end portion 924 can be configured to be oriented toward the second end second end 906 of the frame 902.

[0102] The flow rate reducer 900 can have one or more other features the same as or similar to that described with reference to the fluid flow reducer of Figures 8A and 8B. Forexample, the fluid flow reducer 900 can comprise a spring 930 that couples the second end portion 924 and a support structure 940 at least partially disposed in the lumen 912 to facilitate reversibly moving the plunger fluid guide 920 toward and away from the narrowed portion 914. In some instances, the fluid flow reducer 900 can comprise a plurality of flexible and / or deformable elongate members 950 configured to couple the plunger fluid guide 920 to respective portions of the frame 902, including to respective portions of the narrowed portion 914.

[0103] The frames 602, 702, 802, 902 described with reference to Figures 6A through 6C, 7A through 7C, 8A and 8B and 9 can comprise one or more other features of one or more other frames described herein, including for example the frame 202 described with reference to Figures 2A through 2E. For example, the frames 602, 702, 802, 902 can comprise any number of conduit structures that can at least partially define the respective lumen 612, 712, 812, 912. The frames 602, 702, 802, 902 can have at least a portion that assumes a tubular configuration, including a cylindrical or substantially cylindrical shape. The lumens 612, 712, 812, 912 can be aligned, parallel and / or coaxial with the fluid flow direction at the respective inlet opening 608, 708, 808, 908. In some instances, externally oriented surface portions of the frame 602, 702, 802, 902 can engage with respective portions of the blood vessel wall at the target location. In some instances, a cover can be disposed over at least a portion of the frames 602, 702, 802, 902. In some instances, all or substantially all of the blood flow past the location in the blood vessel can travel through the lumen 612, 712, 812, 912.

[0104] It will be understood that a fluid flow reducer can comprise one or more of the fluid guide structures, arrangements and / or features described herein. For example, a fluid flow reducer can comprise a frame and one or more fluid guides as described herein disposed in the frame to provide a reduced outlet flow rate, including one or more fluid guides described with reference to Figures 2A through 2E, 3A through 3C, 4, 6A through 6C, 7A through 7C, 8 A and 8B, and 9. For example, fluid guides described with reference to 2A through 2E, 3A through 3C, 4, 6A through 6C, 7A through 7C, 8A and 8B, and 9 can be arranged in series within the frame to provide a reduced outlet flow rate. In some instances, an assembly can comprise one or more fluid flow reducers arranged in tandem, each fluid flow reducer comprising one or more of the fluid guides described herein.

[0105] As described herein, one or more flow rate reducers described herein can be disposed in a venous vessel. A diameter of a flow rate reducer, such as a diameter of a frame, can be about 5 millimeters (mm) to about 25 millimeters (mm), including about 10millimeters (mm) to about 25 millimeters (mm), and about 10 millimeters (mm) to about 15 millimeters (mm). In some instances, a diameter of a flow rate reducer, such as a diameter of a frame, can be about 15 millimeters (mm) to about 40 millimeters (mm), including about 15 millimeters (mm) to about 35 millimeters (mm), and about 20 millimeters (mm) to about 35 millimeters (mm).Additional Description of Examples

[0106] Provided below is a list of examples, each of which may include aspects of any of the other examples disclosed herein. Furthermore, aspects of any example described above may be implemented in any of the numbered examples provided below.

[0107] Example 1: A medical implant device can comprise a frame at least partially defining a lumen providing a fluid flow path through the frame from an inlet opening to an outlet opening of the frame. The device can include a first fluid guide disposed in the fluid flow path and coupled to the frame, the first fluid guide being configured to direct a portion of a fluid flow toward a first portion of the frame, and a second fluid guide disposed in the fluid flow path and coupled to the frame at a position distal of the first position, the second fluid guide further being configured to direct the portion of the fluid flow away from the first portion of the frame.

[0108] Example 2: The device of any example herein, in particular example 1, wherein the first fluid guide comprises a first pliable sheet member in a planar configuration, the first pliable sheet member having a first end coupled to first corresponding portions of the frame at the inlet opening and a second end coupled to the frame at second corresponding portions disposed laterally closer to the first portion of the frame than the first corresponding portions.

[0109] Example 3: The device of any example herein, in particular example 2, wherein the first end of the first pliable sheet member is coupled to opposing portions of the frame at the inlet opening.

[0110] Example 4: The device of any example herein, in particular example 2 or3, wherein the first pliable sheet member comprises a trapezoid shape.

[0111] Example 5: The device of any example herein, in particular examples 2 to4, wherein the first fluid guide comprises a first flexible elongate rod extending along at least a portion of the first end of the first pliable sheet member and a second flexible elongate rod extending along at least a portion of the second end of the first pliable sheet member.

[0112] Example 6: The device of any example herein, in particular example 1, wherein the first fluid guide comprises a first pliable sheet member having a first end coupled to first corresponding portions of the frame at the inlet opening and a second end coupled to the frame at second corresponding portions, the first fluid guide comprising an arcuate shape along a lateral dimension.

[0113] Example 7 : The device of any example herein, in particular example 6, wherein the first end of the first pliable sheet member is coupled to opposing portions of the frame at the inlet opening.

[0114] Example 8: The device of any example herein, in particular example 6 or7, wherein the second corresponding portions of the frame are disposed laterally closer to the first portion of the frame than the first corresponding portions.

[0115] Example 9: The device of any example herein, in particular examples 6 to8, wherein the first fluid guide comprises a first flexible elongate rod extending along at least a portion of the first end and a second flexible elongate rod extending along at least a portion of the second end, the second flexible elongate rod assuming an arcuate shape.|0116| Example 10: The device of any example herein, in particular examples 1 to9, wherein the second fluid guide comprises a second pliable sheet member comprising a portion configured to form a path comprising a curvature that directs the fluid flow away from the first portion of the frame.

[0117] Example 11: The device of any example herein, in particular example 10, wherein the second fluid guide comprises a second pliable sheet member having a shape of a parallelogram.

[0118] Example 12: The device of any example herein, in particular example 11, wherein a first corner of the parallelogram is configured to be coupled to the frame at a first position, opposing second and third comers of the parallelogram are configured to be coupled to the frame at respective second and third positions, the second and third positions being closer to a diameter of the frame than the first position, and a fourth comer of the parallelogram is configured to be coupled to the frame at a fourth position, the fourth position being distally disposed from and further from the diameter than the second and third positions. At least a portion of the second pliable sheet member between the first comer and second and third corners and oriented toward the fluid path can be configured to form the curvature that directs the fluid flow away from the portion of the frame.

[0119] Example 13: The device of any example herein, in particular examples 1 to 12, further comprising a third fluid guide configured to be in the fluid flow path distal of thesecond fluid guide, the third fluid guide being configured to direct a portion of the fluid flow to a second portion opposingly oriented relative to the first portion of the frame, and a fourth fluid guide configured to be in the fluid flow path distal of the third fluid guide, the fourth fluid guide being configured to direct the portion of the fluid flow away from the second portion of the frame.

[0120] Example 14: The device of any example herein, in particular example 13, wherein the third and fourth fluid guides have an orientation opposite that of the first and second fluid guides, respectively, around a longitudinal axis of the frame.

[0121] Example 15: The device of any example herein, in particular examples 1 to14, wherein the frame assumes a cylindrical configuration defining the lumen for the fluid path, the inlet opening being a first end of the frame and the outlet opening being a second end of the frame.

[0122] Example 16: The device of any example herein, in particular examples 1 to15, wherein the frame comprises a radially expandable wire frame.

[0123] Example 17: A medical implant assembly can comprise a first flow rate reducer comprising a first frame at least partially defining a first portion of a fluid flow path from a first inlet opening to a first outlet opening and having a first plurality of fluid guides disposed in the fluid flow path, and a second flow rate reducer configured to be disposed distally of the first flow rate reducer, the second flow rate reducer comprising a second frame at least partially defining a second portion of the fluid flow path from a second inlet opening to a second outlet opening and having a second plurality of fluid guides disposed in the fluid flow path.

[0124] Example 18: The assembly of any example herein, in particular example17, wherein the first plurality of fluid guides comprises a first fluid guide comprising a ramp configured to be in the first portion of the fluid flow path to direct a portion of the fluid flow to a portion of the first frame, and a second fluid guide comprising a curvature and configured to be in the first portion of the fluid flow path distal of the first fluid guide to direct the portion of the fluid flow away from the portion of the first frame.

[0125] Example 19: The assembly of any example herein, in particular example18, wherein the second plurality of fluid guides comprises a third fluid guide comprising a ramp configured to be in the second portion of the fluid flow path to direct another portion of the fluid flow to a portion of the second frame, and a fourth fluid guide comprising a curvature and configured to be in the second portion of the fluid flow path distal of the first fluid guide to direct the portion of the fluid flow away from the portion of the second frame.

[0126] Example 20: The assembly of any example herein, in particular example19, wherein the first and third fluid guides are configured to be rotated relative to one another around a longitudinal axis of the first frame or the second frame, and the second and fourth fluid guides are configured to be rotated relative to one another around the longitudinal axis of the first frame or the second frame.

[0127] Example 21: The assembly of any example herein, in particular example20, wherein the first and third fluid guides are configured to be opposingly oriented relative to one another around a longitudinal axis of the first frame or the second frame, and the second and fourth fluid guides are configured to be opposingly oriented relative to one another around the longitudinal axis of the first frame or the second frame.

[0128] Example 22: The assembly of any example herein, in particular examples 19 to 21, wherein each of the first fluid guide, second fluid guide, third fluid guide and fourth fluid guide comprises a respective pliable sheet member.

[0129] Example 23: The assembly of any example herein, in particular example 22, wherein the first and third fluid guides each comprises a pliable sheet member having a trapezoid shape, and the second and fourth fluid guides each comprises a pliable sheet member having a shape of a parallelogram.

[0130] Example 24: The assembly of any example herein, in particular examples 17 to 23, wherein the first frame and the second frame each comprises an expandable frame and is configured to assume a cylindrical shape in an expanded state.

[0131] Example 25: A method of reducing fluid flow rate can comprise providing a flow rate reducer, the flow rate reducer comprising a frame at least partially defining a fluid flow path through the frame from an inlet opening to an outlet opening, and a first and second fluid guide configured to be in the fluid flow path and coupled to the frame, the second fluid guide being distal of the first fluid guide. The method can include flowing a fluid flow into the inlet opening of the flow rate reducer at an inlet flow rate, and flowing the fluid flow past the first fluid guide to divide the fluid flow into a first fluid flow portion and a second fluid flow portion, and to direct the first fluid flow portion toward a first portion of the frame and allow the second fluid flow portion to flow distally. The method can further include flowing the first fluid flow portion past the second fluid guide to direct the first fluid flow portion away from the first portion of the frame and into the second fluid flow portion to provide a combined fluid flow, and flowing the fluid flow out of the outlet opening at an outlet flow rate that is less than the inlet flow rate.

[0132] Example 26: The method of any example herein, in particular example 25, wherein flowing the fluid flow past the first fluid guide comprises allowing the second fluid flow portion to flow along a direction parallel or substantially parallel to a longitudinal axis of the frame.

[0133] Example 27: The method of any example herein, in particular example 25 or 26, further comprising flowing the combined fluid flow past a third fluid guide in the fluid flow path distal of the second fluid guide to divide the combined fluid flow into a two fluid flow portions, and to direct one of the two fluid flow portions toward a second portion of the frame and allow the second of the two fluid flow portions to flow distally, and flowing the first of the two fluid flow portions past the fourth fluid guide to direct the first of the two fluid flow portions away from the second portion of the frame and into the second of the two fluid flow portions.

[0134] Example 28: The method of any example herein, in particular example 27, wherein flowing the combined fluid flow past a third fluid guide comprises directing one of the two fluid flow portions toward a second portion of the frame having an opposing orientation relative to that of the first portion of the frame.

[0135] Example 29: The method of any example herein, in particular examples 25 to 28, wherein flowing the fluid flow out of the outlet opening at the outlet flow rate comprises flowing the fluid flow out of the outlet opening at a flow rate that is between about 10% and about 90% of the inlet flow rate.

[0136] Example 30: The method of any example herein, in particular examples 25 to 29, further comprising deploying the flow rate reducer into an inferior vena cava (IVC), superior vena cava (SVC), or portal vein.

[0137] Example 31: The method of any example herein, in particular example 30, wherein deploying the flow rate reducer into the inferior vena cava (IVC), superior vena cava (SVC), or portal vein comprises advancing the flow rate reducer in a collapsed state into the inferior vena cava (IVC), superior vena cava (SVC), or portal vein, and expanding the flow rate reducer to an expanded state after the flow rate reducer is positioned within the inferior vena cava (IVC), superior vena cava (SVC), or portal vein.

[0138] Example 32: The method of any example herein, in particular examples 25 to 31 , wherein providing the frame comprises providing an expandable frame, providing the first and second fluid guide comprises providing a first pliable sheet member and a second pliable sheet member, and further comprising expanding the flow rate reducer to expand the expandable frame and unfold the first fluid guide and the second fluid guide.

[0139] Example 33: The method of any example herein, in particular example 32, further comprising providing a second flow rate reducer, the second flow rate reducer comprising a second frame at least partially defining a second fluid flow path through the second frame from a second inlet opening to a second outlet opening, and a third and fourth fluid guide configured to be in the second fluid flow path and coupled to the second frame, the fourth fluid guide being distal of the third fluid guide.

[0140] Example 34: The method of any example herein, in particular example 33, further comprising flowing the combined fluid flow into the second inlet opening of the second flow rate reducer at a second inlet flow rate, and flowing the combined fluid flow past the third fluid guide to divide the combined fluid flow into two fluid flow portions, and to direct a first of the two fluid flow portions toward a portion of the second frame and allow a second of the two fluid flow portions to flow distally. The method can include flowing the first of the two fluid flow portions past the fourth fluid guide to direct the first of the two fluid flow portions away from the portion of the second frame into the second of the two fluid flow portions.101411 Example 35: The method of any example herein, in particular example 33 or 34, further comprising providing a flow rate at the second outlet opening that is between about 10% and about 90% of the inlet flow rate.

[0142] The above method(s) can be performed on a living animal or on a simulation, such as on a cadaver, cadaver heart, anthropomorphic ghost, simulator (e.g., with body parts, heart, tissue, etc. being simulated).

[0143] Depending on the example, certain acts, events, or functions of any of the processes or algorithms described herein can be performed in a different sequence, may be added, merged, or left out altogether. Thus, in certain examples, not all described acts or events are necessary for the practice of the processes.

[0144] Conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is intended in its ordinary sense and is generally intended to convey that certain examples include, while other examples do not include, certain features, elements and / or steps. Thus, such conditional language is not generally intended to imply that features, elements and / or steps are in any way required for one or more examples or that one or more examples necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and / or steps are included or are to be performed in any particular example. The terms “comprising,” “including,”“having,” and the like are synonymous, are used in their ordinary sense, and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list. Conjunctive language such as the phrase “at least one of X, Y and Z,” unless specifically stated otherwise, is understood with the context as used in general to convey that an item, term, element, etc. may be either X, Y or Z. Thus, such conjunctive language is not generally intended to imply that certain examples require at least one of X, at least one of Y and at least one of Z to each be present.

[0145] It should be appreciated that in the above description of examples, various features are sometimes grouped together in a single example, Figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that any claim require more features than are expressly recited in that claim. Moreover, any components, features, or steps illustrated and / or described in a particular example herein can be applied to or used with any other example(s). Further, no component, feature, step, or group of components, features, or steps are necessary or indispensable for each example. Thus, it is intended that the scope of the inventions herein disclosed and claimed below should not be limited by the particular examples described above, but should be determined only by a fair reading of the claims that follow.

[0146] It should be understood that certain ordinal terms (e.g., “first” or “second”) may be provided for ease of reference and do not necessarily imply physical characteristics or ordering. Therefore, as used herein, an ordinal term (e.g., “first,” “second,” “third,” etc.) used to modify an element, such as a structure, a component, an operation, etc., does not necessarily indicate priority or order of the element with respect to any other element, but rather may generally distinguish the element from another element having a similar or identical name (but for use of the ordinal term). In addition, as used herein, indefinite articles (“a” and “an”) may indicate “one or more” rather than “one.” Further, an operation performed “based on” a condition or event may also be performed based on one or more other conditions or events not explicitly recited.

[0147] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example examples belong. It be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning thatis consistent with their meaning in the context of the relevant art and not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0148] The spatially relative terms “outer,” “inner,” “upper,” “lower,” “below,” “above,” “vertical,” “horizontal,” and similar terms, may be used herein for ease of description to describe the relations between one element or component and another element or component as illustrated in the drawings. It be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the drawings. For example, in the case where a device shown in the drawing is turned over, the device positioned “below” or “beneath” another device may be placed “above” another device. Accordingly, the illustrative term “below” may include both the lower and upper positions. The device may also be oriented in the other direction, and thus the spatially relative terms may be interpreted differently depending on the orientations.

[0149] Unless otherwise expressly stated, comparative and / or quantitative terms, such as “less,” “more,” “greater,” and the like, are intended to encompass the concepts of equality. For example, “less” can mean not only “less” in the strictest mathematical sense, but also, “less than or equal to.”

Claims

WHAT IS CLAIMED IS:

1. A medical implant device comprising: a frame at least partially defining a lumen providing a fluid flow path through the frame from an inlet opening to an outlet opening of the frame; and a fluid guide structure disposed in the fluid path and coupled to the frame to provide a reduced outlet flow rate at the outlet opening that is less than an inlet flow rate at the inlet opening.

2. The device of claim 1, wherein the fluid guide structure comprises: a first fluid guide coupled to the frame to direct a portion of a fluid flow toward a first portion of the frame; and a second fluid guide to direct the portion of the fluid flow away from the first portion of the frame, the second fluid guide being disposed in the fluid flow path and coupled to the frame at a position distal of the first fluid guide.

3. The device of claim 2, wherein the first fluid guide comprises a ramp to direct the portion of the fluid flow toward the first portion of the frame.

4. The device of claim 2 or 3, wherein the second fluid guide comprises a curved portion to direct the portion of the fluid flow away from the first portion of the frame.

5. The device of claim 2 or 3, wherein the first fluid guide comprises a first pliable sheet member in a planar configuration, the first pliable sheet member having a first end coupled to first corresponding portions of the frame at the inlet opening and a second end coupled to the frame at second corresponding portions disposed laterally closer to the first portion of the frame than the first corresponding portions.

6. The device of claim 5, wherein the first end of the first pliable sheet member is coupled to opposing portions of the frame at the inlet opening.

7. The device of claim 5, wherein the first fluid guide comprises a first flexible elongate rod extending along at least a portion of the first end of the first pliable sheet member and a second flexible elongate rod extending along at least a portion of the second end of the first pliable sheet member.

8. The device of claim 2 or 3, wherein the first fluid guide comprises a first pliable sheet member having a first end coupled to first corresponding portions of the frame at the inlet opening and a second end coupled to the frame at second corresponding portions, the first fluid guide comprising an arcuate shape along a lateral dimension.

9. The device of claim 8, wherein the first end of the first pliable sheet member is coupled to opposing portions of the frame at the inlet opening.

10. The device of claim 8, wherein the second corresponding portions of the frame are disposed laterally closer to the first portion of the frame than the first corresponding portions.

11. The device of claim 8, wherein the first fluid guide comprises a first flexible elongate rod extending along at least a portion of the first end and a second flexible elongate rod extending along at least a portion of the second end, the second flexible elongate rod assuming an arcuate shape.

12. The device of claim 2 or 3, wherein the second fluid guide comprises a second pliable sheet member comprising a curved portion forming a path comprising a curvature that directs the fluid flow away from the first portion of the frame,13. The device of claim 12, wherein the second fluid guide comprises a second pliable sheet member having a shape of a parallelogram.

14. The device of claim 13, wherein: a first comer of the parallelogram is coupled to the frame at a first position; opposing second and third comers of the parallelogram are coupled to the frame at respective second and third positions, the second and third positions being closer to a diameter of the frame than the first position; and a fourth comer of the parallelogram is coupled to the frame at a fourth position, the fourth position being distally disposed from and further from the diameter than the second and third positions, at least a portion of the second pliable sheet member between the first comer and second and third corners and oriented toward the fluid path forming a curvature that directs the fluid flow away from the portion of the frame.

15. The device of claim 2 or 3, further comprising: a third fluid guide disposed in the fluid flow path distal of the second fluid guide, the third fluid guide comprising a ramp to direct a portion of the fluid flow to a second portion opposingly oriented relative to the first portion of the frame; and a fourth fluid guide disposed in the fluid flow path distal of the third fluid guide, the fourth fluid guide comprising a curved portion to direct the portion of the fluid flow away from the second portion of the frame.

16. The device of claim 15, wherein the third and fourth fluid guides have an orientation opposite that of the first and second fluid guides, respectively, around a longitudinal axis of the frame.

17. The device of claim 15, wherein the third and fourth fluid guides, and the first and second fluid guides, have a common orientation, respectively, around a longitudinal axis of the frame.

18. The device of any one of claims 1 to 3, wherein the fluid guide structure comprises a truncated conical fluid guide, the truncated conical fluid guide comprising: a first end oriented toward the inlet opening and defining a first opening aligned with the fluid flow path and a second end of the truncated conical fluid guide oriented toward the outlet opening and defining a second opening aligned with the fluid flow path, the truncated conical fluid guide being reversibly foldable to provide the first opening in a smaller size in response to pressure exerted upon the truncated conical fluid guide by fluid flowing through the inlet opening.

19. The device of claim 18, wherein the truncated conical fluid guide comprises a unitary flexible membrane, the flexible membrane at least partially defining the first and second openings.

20. The device of claim 18, wherein the truncated conical fluid guide comprises a plurality of leaflets circumferentially disposed around a portion of the lumen, each of the plurality of leaflets being spaced from respective adjacent leaflets.

21. The device of any one of claims 1 to 3, wherein the frame comprises a narrowed portion and the fluid guide structure comprises a plunger fluid guide having ateardrop shape and disposed in a portion of the lumen on an inlet side relative to the narrowed portion, the plunger fluid guide being reversibly movable toward and away from the narrowed portion to provide the reduced outlet flow rate.

22. A medical implant device comprising: a frame at least partially defining a lumen for a fluid flow path; and a first series of fluid guides in sequential arrangement along the fluid flow path that first divides a fluid flow into a first and a second fluid flow portion and deflects the first fluid flow portion away from a longitudinal axis of the frame and allows the second fluid flow portion to continue flowing distally, and subsequently directs the first fluid flow portion back toward the longitudinal axis to combine with the second fluid flow portion and provide a combined fluid flow having a flow rate less than that of the fluid flow.

23. The device of claim 22, further comprising a second series of fluid guides disposed in the fluid flow path distally of the first series of fluid guides, the second series of fluid guides first dividing the combined fluid flow into a first and a second combined fluid flow portion and deflecting the first combined fluid flow portion away from the longitudinal axis of the frame and allowing the second combined fluid flow portion to continue flowing distally, and subsequently directing the first combined fluid flow portion back toward the longitudinal axis and combine with the second combined fluid flow portion to provide a recombined fluid flow having a flow rate less than that of the combined fluid flow.

24. The device of claim 23, wherein the second series of fluid guides comprises an opposing orientation about the longitudinal axis of the frame relative to that of the first series of fluid guides.

25. The device of any one of claims 22 to 24, wherein each of the first and second series of fluid guides comprises a first fluid guide having common features and a second fluid guide having common features.

26. A medical implant assembly comprising: a first flow rate reducer comprising a first frame at least partially defining a first portion of a fluid flow path from a first inlet opening to a first outlet opening and having a first plurality of fluid guides disposed in the fluid flow path; anda second flow rate reducer configured to be disposed distally of the first flow rate reducer, the second flow rate reducer comprising a second frame at least partially defining a second portion of the fluid flow path from a second inlet opening to a second outlet opening and having a second plurality of fluid guides disposed in the fluid flow path.

27. The assembly of claim 26, wherein the first plurality of fluid guides comprises: a first fluid guide comprising a ramp configured to be in the first portion of the fluid flow path to direct a portion of the fluid flow to a portion of the first frame; and a second fluid guide comprising a curvature and configured to be in the first portion of the fluid flow path distal of the first fluid guide to direct the portion of the fluid flow away from the portion of the first frame.

28. The assembly of claim 27, wherein the second plurality of fluid guides comprises: a third fluid guide comprising a ramp configured to be in the second portion of the fluid flow path to direct another portion of the fluid flow to a portion of the second frame; and a fourth fluid guide comprising a curvature and configured to be in the second portion of the fluid flow path distal of the first fluid guide to direct the portion of the fluid flow away from the portion of the second frame.

29. The assembly of claim 28, wherein the first and third fluid guides are configured to be rotated relative to one another around a longitudinal axis of the first frame or the second frame, and the second and fourth fluid guides are configured to be rotated relative to one another around the longitudinal axis of the first frame or the second frame.

30. The assembly of claim 29, wherein the first and third fluid guides are configured to be opposingly oriented relative to one another around a longitudinal axis of the first frame or the second frame, and the second and fourth fluid guides are configured to be opposingly oriented relative to one another around the longitudinal axis of the first frame or the second frame.

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