Bidirectional cannula

Abstract

One bidirectional cannula (100) includes a cannula body (102) with open distal (106) and proximal (108) ends, a cannula blood flow exit port (112) formed in an intermediate segment (114) of the cannula body, and a retainer (104) coupled to the cannula body and movable between stowed and deployed configurations.

Description

BIDIRECTIONAL CANNULACROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Patent Application No. 63 / 707,111, filed October 14, 2024, the entire disclosure which is incorporated by reference for all purposes.FIELD

[0002] The present disclosure relates to a bidirectional cannula.BACKGROUND

[0003] Unless otherwise indicated in the present disclosure, the materials described in the present disclosure are not prior art to the claims in the present application and are not admitted to be prior art by inclusion in this section.

[0004] Extracorporeal circulation is used as heart adjuvant therapy for heart surgery’ of patients, or in a state of heart failure, and femoral arterial cannulation is commonly used to supply oxygenated blood. Such femoral arterial cannulation is carried out by surgically exposing blood vessels, but, in many cases, a Seidinger’s technique whereby a guidewire is inserted via the skin is used. At this time, a cannula is inserted into the femoral artery in the vicinity of the groin region, and thus the biggest problem is distal limb perfusion. In femoral arterial cannulation, blood is supplied to the upper body part above the thigh of a patient, but distal perfusion decreases or is blocked by a thick cannula. Thus, while a femoral arterial cannula is maintained, blood is not adequately supplied from the legs below the thigh to a distal portion, e.g., the feet, and, accordingly, there may be a risk for ischemic damage or necrosis of the cannulated leg.

[0005] Thus, to prevent the occurrence of these problems, various techniques, such as separate antegrade catheterization, posterior tibial artery cannulation, and the like which supply blood to both sides of the legs, are conventionally used, but all the techniques cause delays, complications or damage of blood vessels, and thus there are technical difficulties in applying these techniques.

[0006] The subject matter claimed in the present disclosure is not limited to implementations that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one example technology area where some implementations described in the present disclosure may be practiced.SUMMARY

[0007] The present disclosure relates to bidirectional cannulas and related methods. Specifically, the present disclosure is directed to bidirectional cannulas that provide perfusion or blood flow in two opposing directions within a blood vessel through a single incision, as well as methods of inserting such cannulas into blood vessels.

[0008] In some embodiments, a cannula includes a cannula body and a retainer. The cannula body is elongated and hollow. The cannula body has a distal end and a proximal end that are both open and a cannula blood flow exit port formed in an intermediate segment of the cannula body between the distal end and the proximal end and facing an opposite direction from the open distal end. The retainer is coupled to the cannula body and is movable between a stowed configuration for insertion into a vessel of a patient and a deployed configuration.

[0009] In some embodiments, a cannula includes a cannula body and a balloon. The cannula body is elongated and hollow. The cannula body has a distal end and a proximal end that are both open and one or more cannula blood flow exit ports between the distal end and the proximal end. The balloon is coupled to the cannula body between the distal end and the proximal end in fluid communication with the one or more cannula blood flow exit ports of the cannula body. The balloon includes a proximal surface that defines one or more balloon blood flow exit ports. The balloon may redirect blood flow directly to a distal portion of the cannulated leg in use.

[0010] In some embodiments, a cannula assembly includes a first cannula and a second cannula. The first cannula includes a cannula body having a distal end and a proximal end. The cannula body defines a first lumen that extends from the distal end to the proximal end and a second lumen that extends at least partially between the distal end and the proximal end. In a plane perpendicular to a length of the first cannula, the first lumen has a larger cross-sectional area than the second lumen. The second cannula is receivable within the second lumen of the first cannula. The second lumen has a turn at its distal end that forces the second cannula to change direction at the turn where the second cannula exits the second lumen of the first cannula.

[0011] In some embodiments, a method to insert a cannula into a blood vessel of a patient involves the cannula having a cannula body having an open distal end, an intermediate segment proximal to the distal end in which a cannula blood flow exit port is formed, and a retainer coupled to the cannula body and movable between a stowed configuration and a deployed configuration. The method includes accessing the blood vessel of the patient w ith a needle. The method includes advancing a guidewire through the needle into the blood vessel. The method includes removing the needle while retaining the guidewire in the blood vessel. The method includes advancing a dilator and the cannulaalong the guidewire into the blood vessel until: the distal end of the cannula is positioned to direct blood flow from the cannula in a first direction in the blood vessel; the cannula blood flow exit port is arranged to direct blood flow from the cannula in a second direction in the blood vessel that is opposite the first direction; and a retainer in a stowed configuration coupled to the cannula body is at least partially positioned within the blood vessel. The method includes removing the dilator. The method includes altering the retainer to a deployed configuration in which a portion of the retainer is deployed within the blood vessel.

[0012] In some embodiments, a method to insert a cannula into a blood vessel of a patient involves the cannula having a cannula body having an open distal end and a balloon coupled to the cannula body proximal to the distal end, the balloon including a proximal surface that defines one or more balloon blood flow- exit ports. The method includes accessing the blood vessel of the patient with a needle. The method includes advancing a guidewire through the needle into the blood vessel. The method includes removing the needle while retaining the guidewire in the blood vessel. The method includes advancing a dilator and the cannula along the guidewire into the blood vessel until: the distal end of the cannula is positioned to direct blood flow from the cannula in a first direction in the blood vessel; and the balloon is positioned in the blood vessel with the one or more balloon blood flow exit ports defined in the proximal surface of the balloon positioned to direct blood flow7from the cannula in a second direction in the blood vessel that is opposite the first direction. The method includes removing the dilator.

[0013] In some embodiments, a method to insert a cannula assembly into a blood vessel of a patient involves the cannula assembly having a first cannula having a cannula body with a distal end and a proximal end, the cannula body defining a first lumen that extends from the distal end to the proximal end and a second lumen that extends at least partially between the distal end and the proximal end. The method includes accessing a blood vessel of a patient with a needle. The method includes advancing a guidewire through the needle into the blood vessel. The method includes removing the needle w hile retaining the guidewire in the blood vessel. The method includes advancing a dilator and the first cannula along the guidewire into the blood vessel until: the distal end of the cannula body of the first cannula is positioned to direct blood flow- from the first cannula in a first direction in the blood vessel; and a distal end of the second lumen is positioned within the blood vessel while a proximal end of the second lumen remains outside the blood vessel. The method includes advancing a second cannula through the second lumen of the first cannula until distal and proximal ends of the second cannula extend from the distal and proximal ends of the second lumen, the distal end of the second lumen having a turn that forces the second cannula to change direction at the turn w here the second cannula exits the second lumen, the distal end of thesecond cannula positioned to direct blood flow from the second cannula in a second direction in the blood vessel that is opposite the first direction. The method includes removing the dilator.

[0014] In one or more of the various devices, systems, and / or methods herein, one or more cannula blood flow exit ports may be, in the aggregate, at least as large as one or more balloon blood flow exit ports in the aggregate. Alternatively or additionally, a size of an opening at the distal end of the cannula may be larger than one or more cannula blood flow exit ports in the aggregate.

[0015] One or more of the devices, systems, and / or methods herein may include or involve a cannula hub that has two or more input ports and one or more output ports. The output port may be coupled to the proximal end of the cannula. One of the two input ports may be coupled to cardiopulmonary bypass equipment, also referred to herein as a perfusion source or blood flow source, to flow blood into the patient. The other input port may be used for inserting devices into or through the cannula while maintaining the connection to the bypass equipment through the other input port. For example, a cannulated patient on mechanical circulatory support {e.g., coupled to the bypass equipment) may have a coronary angioplasty balloon inserted through one of the input ports into and through the cannula and up the femoral artery to a desired location in the circulatory system to perform an interventional procedure. The cannula hub permits the interventional procedure to be performed through the same incision as the cannula (thereby avoiding the additional trauma of a second incision) and while maintaining the connection to and operation of the bypass equipment. In some embodiments, the cannula hub may include a flange between the output port and the two input ports. In these and other embodiments, the flange may be configured to contact tissue of a patient at an insertion site of a cannula to inhibit rotation of the cannula while the cannula is inserted in the patient.

[0016] One or more of the devices, systems, and / or methods herein may include or involve a cannula hub coupled to a cannula body. The cannula hub may include an output port coupled to the proximal end of the cannula body and an input port. In some embodiments, the cannula hub may include a flange between the output port and the input port. In these and other embodiments, the flange may be configured to contact tissue of a patient at an insertion site of a cannula to inhibit rotation of the cannula while the cannula is inserted in the patient.

[0017] In some embodiments, a cannula or cannula assembly may include a dilator configured with a groove extending longitudinally for at least a portion of an exterior of the dilator to create a priming fluid channel between the outside of the dilator and the inside of the cannula body, the priming fluid channel being configured such that priming fluidintroduced into the priming fluid channel flows into a balloon coupled to the cannula or cannula assembly. Additionally or alternatively, the priming fluid channel may be configured to aspirate blood, be used to evaluate placement of the cannula or cannula assembly, and / or to deliver contrast media for evaluating placement of the balloon using an imaging technique (e.g., fluoroscopy, x-ray, etc.).

[0018] The methods described herein may be performed on a living animal or on a simulation, such as on a cadaver, cadaver heart, anthropomorphic ghost, simulator (for example, w ith body parts, heart, tissue, etc. being simulated).

[0019] The foregoing and other objects, features, and advantages of the disclosed technology will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures.BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIGS. 1A-1B depict an example bidirectional cannula w ith a retainer.

[0021] FIG. 2 depicts the cannula of FIGS. 1A-1B with the retainer in a stowed configuration.

[0022] FIG. 3 is a cross-sectional side view’ of the cannula of FIGS. 1A-1B inserted into a blood vessel.

[0023] FIGS. 4A-4B depict another example bidirectional cannula.

[0024] FIG. 5 is a cross-sectional side view of the cannula of FIGS. 4A-4B inserted into a blood vessel.

[0025] FIG. 6 illustrates a prototype of the cannula of FIGS. 4A-4B.

[0026] FIG. 7A is a perspective view of a bidirectional cannula assembly that includes a first cannula and a second cannula.

[0027] FIG. 7B is a cross-sectional perspective view of the first cannula of FIG. 7A.

[0028] FIG. 8 is a cross-sectional side view’ of the cannula assembly’ of FIGS. 7A-7B inserted into a blood vessel.

[0029] FIGS. 9A-9B depict another example bidirectional cannula.

[0030] FIGS. 10A-10B depict another example bidirectional cannula.

[0031] FIGS. 11A-11B depict another example bidirectional cannula.

[0032] FIG. 12 is a cross-sectional side view of the cannula of FIGS. 11A-11B inserted into a blood vessel.

[0033] FIGS. 13A-13B illustrate an example valve assembly that may be coupled to either input port of an example cannula hub.

[0034] FIGS. 14A-14B depict another example bidirectional cannula.

[0035] FIGS. 15A-15B depict an example cannula hub that may be coupled to an example bidirectional cannula.

[0036] FIGS. 16A-16C depict example arrangements of an example bidirectional cannula that may be configured to prime a ballon of the bidirectional cannula.DETAILED DESCRIPTIONGeneral Considerations

[0037] It should be understood, with the benefit of the present disclosure, that the disclosed examples may be adapted to deliver and implant cannulas in any desired blood vessel of a vascular system (for example, the femoral artery or vein, the axillary7artery or vein, etc.) to provide both retrograde and antegrade blood flow at the insertion site. Some embodiments may further include a cannula hub coupled to the cannula to permit simultaneous circulatory7support and vessel access through the cannula.

[0038] For purposes of this description, certain aspects, advantages, and novel features of the examples of this disclosure are described herein. The disclosed methods, apparatus, and systems should not be construed as being limiting in any way. Instead, the present disclosure is directed toward all novel and nonobvious features and aspects of the various disclosed examples, alone and in various combinations and sub-combinations with one another. The methods, apparatus, and systems are not limited to any specific aspect or feature or combination thereof, nor do the disclosed examples require that any one or more specific advantages be present or problems be solved. The technologies from any example may be combined with the technologies described in any one or more of the other examples. In view of the many possible examples to which the principles of the disclosed technology may be applied, it should be recognized that the illustrated examples are only preferred examples and should not be taken as limiting the scope of the disclosed technology.

[0039] Although the operations of some of the disclosed examples are described in a particular, sequential order for convenient presentation, it should be understood that this manner of description encompasses rearrangement, unless a particular ordering is required by specific language set forth below. For example, operations described sequentially may in some cases be rearranged or performed concurrently. Moreover, for the sake of simplicity, the attached figures may not show the various ways in which the disclosed methods may be used in conjunction with other methods. Additionally, the description sometimes uses terms like “provide” or “achieve” to describe the disclosed methods. These terms are high-levelabstractions of the actual operations that are performed. The actual operations that correspond to these terms may vary depending on the particular implementation and are readily discernible by one of ordinary skill in the art.

[0040] As used in this application and in the claims, the singular forms “a,” “an,” and “the” include the plural forms unless the context clearly dictates otherwise. Additionally, the term “includes” means “comprises.” Further, the terms “coupled” and “connected” generally mean electrically, electromagnetically, fluidly, anatomically, and / or physically (for example, mechanically or chemically) coupled or linked and does not exclude the presence of intermediate elements between the coupled or associated items absent specific contrary language. As used herein, the term “and / or” used between the last two of a list of elements means any one or more of the listed elements. For example, the phrase “A, B, and / or C” means “A”, “B,”, “C”, “A and B”, “A and C”, “B and C”, or “A, B, and C.”

[0041] As used herein, the term “proximal” refers to a position, direction, or portion of a device that is closer to the user (e.c / ., clinician) and further away from the insertion site. As used herein, the term “distal” refers to a position, direction, or portion of a device that is further away from the user and closer to the insertion site. Thus, for example, proximal motion of a device is motion of the device away from the insertion site and toward the user (for example, out of the patient’s body), while distal motion of the device is motion of the device away from the user and toward the insertion site (for example, into the patient’s body). The terms “longitudinal” and “axial” refer to an axis extending in the proximal and distal directions, unless otherwise expressly defined.

[0042] Directions and other relative references (for example, inner, outer, upper, lower, etc.) may be used to facilitate discussion of the rawings and principles herein, but are not intended to be limiting. For example, certain terms may be used such as “inside,” “outside,”, “top,” “down,” “interior,” “exterior,” and the like. Such terms are used, where applicable, to provide some clarity of description when dealing with relative relationships, particularly with respect to the illustrated examples. Such terms are not, however, intended to imply absolute relationships, positions, and / or orientations. For example, with respect to an object, an “upper” part may become a “lower” part simply by turning the object over. Nevertheless, it is still the same part and the object remains the same.

[0043] The terms “longitudinal” and “axial” refer to an axis extending in the upstream and downstream directions, or in the proximal and distal directions, unless otherwise expressly defined.

[0044] Although there are alternatives for various components, features, parameters, operating conditions, etc., set forth herein, that does not mean that those alternatives arenecessarily equivalent and / or perform equally well. Nor does it mean that the alternatives are listed in a preferred order unless stated otherwise.

[0045] As used herein, the terms “integrally formed” and “unitary construction” refer to a construction that does not require any sutures, fasteners, or other securing means to attach two portions of the construction together.Example Cannulation Procedure

[0046] Described herein are various systems, apparatuses, methods, or the like, that may be used in, with, or as cannulas to ensure adequate arterial flow and / or venous drainage to a patient’s limbs during peripherally cannulated extracorporeal membrane oxygenation (ECMO), open heart surgery (OHS), minimally invasive heart surgery (MICS), or the like.

[0047] In certain examples, a cannula or cannula assembly may be configured to be inserted into the patient’s peripheral vascular system to supply blood to the blood vessel in both directions through a single insertion site. The bidirectional blood flow may be achieved by flowing blood through both a distal end of the cannula, e.g., for retrograde flow in the case of an arterial placement, as well as through one or more holes or ports facing the opposite direction, e.g., for antegrade flow in the case of the arterial placement. In addition, the cannula or cannula assembly may have one or more structural features to inhibit accidental removal of the cannula or cannula assembly from the blood vessel. For example, the cannula or cannula assembly may include a deployable retainer that may be deployed after insertion into the blood vessel and / or two cannulas (inserted through the same insertion site) that collectively form a T-anchor within the blood vessel. The retainer may alternatively or additionally be used to ensure correct orientation of a perfusion hole in the cannula, directing flow to the foot direction of the cannulated limb.

[0048] In general, the cannulas herein may be inserted into a blood vessel of a patient by first accessing the blood vessel w ith a hollow needle. In particular, the needle may be partially inserted into the blood vessel such that a distal end of the needle is positioned within the blood vessel and a proximal end of the needle is positioned outside of the blood vessel and accessible to a user (e.g., clinician). With the needle in place, a guidewire may be advanced through the needle until a distal portion of the guidewire is inside the blood vessel and a proximal portion of the guidewire is outside of the blood vessel and accessible to the user. The needle may then be removed w hile retaining the guidewire in place in the blood vessel (with the proximal portion outside of the blood vessel). Following removal of the needle, a dilator and cannula may then be inserted over the guidewire and into the blood vessel until the cannula is at a desired depth. The dilator may have a rounded tip to avoid puncturing the blood vessel from the inside during insertion and the dilator may gradually increase in diameter moving proximally away from the tip to the distal end of the cannula. Assuch, as the dilator and cannula are inserted into the blood vessel, the dilator may dilate the incision to accommodate the cannula. As the dilator and cannula are inserted to a desired depth within the vessel, the rounded tip of the dilator inhibits the distal end of the cannula from catching on or puncturing the interior of the blood vessel. After inserting the dilator and cannula to the desired depth, the dilator may be removed while retaining the cannula in place within the blood vessel. A proximal end of the cannula may then be coupled to a blood flow source which may be turned on to flow blood through the cannula into the blood vessel.

[0049] In some embodiments, the cannula includes a cannula body having an open distal end, an intermediate segment proximal to the distal end in which a cannula blood flow exit port is formed, and a retainer coupled to the cannula body and movable between a stowed configuration and a deployed configuration, such as in FIGS. 1A-1B. In this and other embodiments, the method of inserting the cannula into the blood vessel may include advancing the dilator and the cannula along the guidewire into the blood vessel until the following conditions are met. First, the distal end of the cannula is positioned to direct blood flow from the cannula in a first direction in the blood vessel. Second, the cannula blood flowexit port is arranged to direct blood flow from the cannula in a second direction in the blood vessel that is opposite the first direction. Third, the retainer in the stowed configuration coupled to the cannula body is at least partially positioned within the blood vessel. With the cannula at the desired position, the retainer may be altered to the deployed configuration in w hich a portion of the retainer is deployed wdthin the blood vessel. The alteration of the retainer to the deployed configuration may occur automatically in response to removal of the dilator from the cannula or via direct manual manipulation / advancement from outside the patient.

[0050] The retainer may include a tube (or multiple tubes) or integral lumen coupled to an exterior of the cannula body and an expandable structure (or multiple expandable structures) retained within the tube in the stowed configuration, as illustrated in FIGS. 1A- 1B. In this and other embodiments, altering the retainer to the deployed configuration may include manually or automatically forcing the expandable structure out of the tube to the deployed configuration in the blood vessel. The expandable structure may include a wire and in response to the expandable structure being forced out of the tube, the method may further include the wire forming a framed protrusion that extends away from the intermediate segment near the cannula blood flow exit port and inhibits occlusion of the cannula blood flow exit port by a sidewall of the blood vessel.

[0051] After the cannula has been inserted to the desired depth, the dilator has been removed, the retainer has been deployed, and the proximal end of the cannula has been coupled to a blood flow source, blood may flow through the cannula from the blood flowsource and into the blood vessel in both the first direction and the second direction. For example, blood may flow out of the distal end of the cannula in the first direction in the blood vessel w hile also flowing out of the cannula blood flow exit port in the second direction in the blood vessel that is opposite the first direction.

[0052] In some embodiments, the cannula includes a cannula body having an open distal end and a balloon coupled to the cannula body proximal to the distal end, the balloon including a proximal surface that defines one or more balloon blood flow- exit ports, such as in FIGS. 4A-4B. In this and other embodiments, the balloon may be collapsed against the cannula body as the ballon coupled to the cannula is inserted through the incision into the blood vessel while advancing the dilator and the cannula along the guidewire and into the blood vessel. Alternatively or additionally, the method of inserting the cannula into the blood vessel may include advancing the dilator and the cannula along the guidewire into the blood vessel until the following conditions are met. First, the distal end of the cannula is positioned to direct blood flow from the cannula in a first direction in the blood vessel. Second, the balloon is positioned in the blood vessel with the balloon blood flow exit ports defined in the proximal surface of the balloon positioned to direct blood flow from the cannula in a second direction in the blood vessel that is opposite the first direction. After the cannula has been inserted to the desired depth, the dilator has been removed, and the proximal end of the cannula has been coupled to a blood flow source, blood may fill and expand the balloon within the blood vessel with blood from the blood flow source. In addition, blood may flow through the cannula from the blood flow source and into the blood vessel through the distal end of the cannula in the first direction and through the balloon in the second direction.

[0053] In some embodiments, the cannula is a first cannula of a cannula assembly that also includes a second cannula, the first cannula having a cannula body w ith a distal end and a proximal end, the cannula body defining a first lumen that extends from the distal end to the proximal end and a second lumen that extends at least partially betw een the distal end and the proximal end, such as in FIGS. 7A-7B. In this and other embodiments, the method of inserting the cannula assembly into the blood vessel may include advancing the dilator and the first cannula along the guidewire into the blood vessel until the following conditions are met. First, the distal end of the cannula body of the first cannula is positioned to direct blood flow from the first cannula in a first direction in the blood vessel. Second, a distal end of the second lumen is positioned within the blood vessel w-hile a proximal end of the second lumen remains outside the blood vessel. The method may also include advancing a second cannula through the second lumen of the first cannula until distal and proximal ends of the second cannula extend from the distal and proximal ends of the second lumen, the distal end of the second lumen having a turn that forces the second cannula to change direction at theturn where the second cannula exits the second lumen, the distal end of the second cannula positioned to direct blood flow from the second cannula in a second direction in the blood vessel that is opposite the first direction.

[0054] Proximal ends of both the first cannula and the second cannula may each be coupled to the blood flow source. Blood from the blood flow source may flow through the first cannula and into the blood vessel, including out of the distal end of the first cannula in the first direction in the blood vessel. Blood from the blood flow source may also flow through the second cannula and into the blood vessel, including out of the distal end of the second cannula in the second direction in the blood vessel that is opposite the first direction.

[0055] In some embodiments, the second cannula includes one or more cannula blood flow exit ports formed in a sidewall of the second cannula closer to the distal end of the second cannula than the proximal end of the second cannula. In this and other embodiments, advancing the second cannula through the second lumen of the first cannula may include advancing the second cannula through the second lumen of the first cannula until the cannula blood flow exit ports of the second cannula are positioned distal to the distal end of the second lumen of the first cannula and within the blood vessel.

[0056] In some embodiments, a priming procedure may be performed prior to or during insertion of the cannula or cannula assembly to remove air from the cannula, cannula assembly, and / or one or more parts of the cannula or cannula assembly (e.g., a balloon). In some embodiments, the priming procedure may include introducing a priming fluid such as saline, heparinized saline, sterile water, blood, a dextrose solution, and / or an electrolyte solution into one or more parts of the cannula or cannula assembly. For example, the priming fluid may be introduced to a lumen of the cannula and / or a balloon via one or more input ports, valve assemblies, and / or other channels. In some embodiments, the priming procedure may include coupling a fluid delivery device (e.g., a syringe, an infusion set, etc.) to an input port, valve assembly, and / or other channel. In some embodiments, the priming fluid is introduced via a lumen formed by a channel formed in a dilator and a sidewall of a cannula, the lumen in fluid communication with one or more cannula blood flow exit ports and a balloon of the cannula. In some embodiments, the priming fluid is introduced via a central lumen of a dilator that is in fluid communication with the one or more cannula blood flow exit ports and balloon of the cannula. In some embodiments, the priming fluid is introduced via a secondary lumen of a dilator that is in fluid communication with the one or more cannula blood flow exit ports and balloon of the cannula.

[0057] In some embodiments, the size of an opening at the distal end of the cannula may be larger than the size of the cannula blood flow exit port, or of the aggregate size of multiple cannula blood flow exit ports if there are more than one. Additionally or alternatively, thecannula blood flow exit port may be at least as large as an aggregate size of one or more balloon blood flow exit ports. In some embodiments, the relative size of one or more cannula blood flow’ exit ports, one or more balloon blood flow exit ports, and / or one or more openings at the distal end of a cannula may allow for the cannula and / or a ballon coupled to the cannula to self-prime. For example, the relative sizes may be configured to create and / or maintain positive pressure in the cannula such that in response to being inserted into a patient, blood will flow through the cannula pushing air out of the cannula and / or the balloon.

[0058] In some embodiments, the cannula includes or is coupled to a cannula hub that includes one or more anti-rotation features. Such features may include a flange configured to contact tissue of a patient at or near an insertion site of the cannula to inhibit rotation of the cannula while the cannula is inserted in the patient. Such a flange may include one or more flange holes for placement of sutures between the flange and the tissue of the patient to secure the cannula hub and cannula to the patient.Example Cannula

[0059] Example embodiments herein generally relate to bidirectional cannulas, e.g., cannulas that provide perfusion in opposite directions within a blood vessel. Such cannulas may be inserted into the blood vessel through a single incision and may include one or more features to ensure proper positioning within the blood vessel, reduce a likelihood of occluding all of the openings or ends that supply blood flow in a given direction, increase a likelihood that at least one opening or end in each direction is able to supply blood flow, anchor the cannula within the blood vessel to reduce a likelihood of unintentional withdraw al of the cannula from the blood vessel, ensure adequate blood flow through the cannula (in multiple directions and / or through one or more structures of the cannula), inhibit rotation when in use at an insertion site, or provide one or more other features or functionality.

[0060] In these and other embodiments, the cannulas may have one or more markings, such as depth markings, to determine how far the cannula has been inserted into the blood vessel. The markings may be used during insertion of the cannula into the blood vessel to ensure the cannula is inserted into the blood vessel to a desired depth. Alternatively or additionally, the depth markings may be used to visually assess and ensure the cannula remains at a desired insertion depth after insertion.

[0061] In some embodiments, the cannulas described herein may include one or more marker bands or radio opaque markers at one or more locations on the cannulas, such as at distal ends, on or in distal segments or intermediate segments of the cannulas, or more generally at any desired location. The marker bands or radio opaque markers may includeplatinum iridium, tantalum, gold, tungsten, or other desired marker. The marker bands or radio opaque markers may enable better visualization of positioning of the cannulas during insertion. For example, an imaging device may be used to image the marker bands or radio opaque markers of the cannulas relative to a patient’s anatomy to ensure that a desired relative placement or insertion is achieved.

[0062] In some embodiments, the cannulas herein may include a connector on their proximal ends to connect to a cardiopulmonary circuit. For example, each of the connectors may include a luer lock connector (e.g., 3 / 8" x 3 / 8") to connect the cannula to the cardiopulmonary circuit. Blood flow may enter the cannula through the connector and the proximal end of the cannula. The cardiopulmonaiy circuit may include a blood flow source.

[0063] FIGS. 1A-1B depict an example bidirectional cannula too, arranged in accordance with at least one embodiment herein. FIGS. 1A and 1B respectively include a perspective view and a cross-sectional perspective view of the cannula too. As illustrated in FIGS. 1A-1B, the cannula too includes a cannula body 102 and a retainer 104.

[0064] The cannula body 102 is elongated and hollow and has a distal end 106 and a proximal end 108 that are both open, the cannula body 102 defining a lumen 110 that extends from the distal end 106 to the proximal end 108. The cannula body 102 also includes one or more cannula blood flow exit ports 112 formed in an intermediate segment 114 of the cannula body 102 between the distal end 106 and the proximal end 108. In operation, blood flows through the cannula too by entering through the proximal end 108, traveling completely or partially through the lumen 110, and exiting through the distal end 106 or the cannula blood flow exit port 112 in the intermediate segment 114.

[0065] In some embodiments, an opening 109 at the distal end 106 of the cannula too may be larger in size than the one or more cannula blood flow exit ports 112, in the aggregate. Such a configuration of opening and port sizes may facilitate a higher volume of blood flow ing from the distal end 106 of the cannula too in a corresponding direction w ith in a blood vessel than from the one or more cannula blood flow exit ports 112 in the opposite direction within the blood vessel.

[0066] Although not depicted in FIGS. 1A-1B, the cannula body 102 may be or include a body of wire wound or braided tubing in which wound or braided wire is formed within or around tubing. The wire wound or braided tubing may have any suitable size, such as 15 French (Fr) (z.e., 5 millimeter (mm) diameter), 17 Fr (z.e., 5.6mm diameter), 19 Fr (z.e., 6.3 mm diameter), or other desired size. In some embodiments, the entire cannula body 102 may include wire wound or braided tubing. In some embodiments, the cannula body 102 may include one or more wire wound or braided tubing sections and one or more tubingsections that are devoid of wire. For example, the intermediate segment 114, or at least a portion of the intermediate segment 114 in which the cannula blood flow exit port 112 is formed, may be tubing devoid of wire. The absence of wire in the portion of the intermediate segment 114 in which the cannula blood flow7exit port 112 is formed may simplify manufacturing of the cannula too. Alternatively or additionally, the cannula body 102 may include a tapered tip at the distal end 106 of a biocompatible metal or other material.

[0067] The cannula body 102 further includes a first or distal segment 116 and a second or proximal segment 118 that are connected by the intermediate segment 114. In some embodiments, the first and second segments 116, 118 may be parallel to each other while the intermediate segment 114 may be angled (e.g., at a non-zero angle) relative to the first and second segments 116, 118. Alternatively or additionally, the intermediate segment 114 may include or be referred to as an ankle of the cannula body 102.

[0068] In general, the retainer 104 is coupled to the cannula body 102 and is movable between a stowed configuration for insertion into a vessel of a patient and a deployed configuration. The retainer 104 is depicted in the deployed configuration in FIGS. 1A-1B and in the stowed configuration in FIG. 2 discussed in more detail elsewhere herein. In the deployed configuration depicted in FIGS. 1A-1B, the retainer 104 may be configured to retain the cannula too inserted in a blood vessel, e.g., at a desired depth. Alternatively or additionally, in the deployed configuration, the retainer 104 may be configured to inhibit removal of the cannula too from the blood vessel.

[0069] The retainer 104 may be implemented in any desired form. In the illustrated embodiment, the retainer 104 includes one or more tubes 120 coupled to an exterior of the cannula body 102. In particular, each tube 120 is coupled primarily to an exterior of the second segment 118 of the cannula body 102 and to a portion of an exterior of the intermediate segment 114 of the cannula body 102. The retainer 104 further includes one or more expandable structures 122, each extending from a corresponding one of the tubes 120 in the deployed configuration of FIGS. 1A-1B. While illustrated as two independent expandable structures 122, the expandable structures 122 may instead be a single expandable structure 122 with each end inserted into a different one of the tubes 120 e.g., the single expandable structure 122 having a u-shape connecting the two ends, the u-shape positioned beneath the first segment 116 in the deployed configuration of FIGS. 1A-1B).

[0070] FIG. 2 depicts the cannula too of FIGS. 1A-1B with the retainer 104 in the stow ed configuration, arranged in accordance with at least one embodiment herein. With combined reference to FIGS. 1A-2, in some embodiments, each expandable structure 122 includes an expandable portion 122A (FIGS. 1A-1B) that is expanded and visible when the retainer 104 is in the deployed configuration, and a plunger portion 122B (FIG. 2) that is visible w hen theretainer 104 is in the stowed configuration. Each expandable portion 122A and plunger portion 122B may be a different part of the same expandable structure 122. For example, each expandable structure 122 may include a wire with the expandable portion 122A including one end of the wire and the plunger portion 122B including an opposite end of the wire.

[0071] The expandable portion 122A of each expandable structure 122 may be stowed within the corresponding tube 120 when the retainer 104 is in the stowed configuration (FIG. 2), with the plunger portion 122B extending from a proximal end of the corresponding tube 120. In the stowed configuration, the retainer 104 (and in particular, the expandable portions 122A) is positioned tight against the cannula body 102, e.g., for and during insertion of the cannula too into the vessel, and the expandable portions 122A in an unexpanded state within the tubes 120.

[0072] In some embodiments, the retainer 104 is moved from the stowed configuration of FIG. 2 to the deployed configuration of FIGS. 1A-1B by applying a distally-directed force against proximal ends of the plunger portions 122B to force the plunger portions 122B into the tubes 120. In turn, the expandable portions 122A may be forced distally out of the tubes 120. For example, a user may push distally against proximal ends of the plunger portions 122B using a thumb or other digit or a tool to push the plunger portions 122B into the tubes 120 and the expandable portions 122A out of the tubes 120. As another example, the expandable structure 122 may be deployed (e.g., the expandable portions 122A may be forced out of the tubes 120) automatically in response to removal of a dilator from the lumen 110 of the cannula too after insertion of the cannula too into the vessel. The plunger portion 122B of each expandable structure 122 may be stowed within the corresponding tube 120 w hen the retainer 104 is in the deployed configuration (FIGS. 1A-1B), with the expandable portion 122A extending from a distal end of the corresponding tube 120.

[0073] In some examples, each expandable structure 122 includes a shape memory material that is shape set and / or pre-configured to expand the expandable structure 122 to the deployed configuration depicted in FIGS. 1A-1B when unconstrained (for example, after insertion into a vessel). For example, each expandable structure 122 may contain a shape memory alloy with super-elastic properties, such as Nitinol. In some examples, each expandable structure may contain a ternary shape memory alloy with super-elastic properties, such as NiTiX where X may be chromium (Cr), cobalt (Co), zirconium (Zr), hafnium (Hf), or the like. Alternatively or additionally, each expandable structure 122 may contain another biocompatible material instead of or in addition to Nitinol, such as stainless steel.

[0074] As previously indicated, each expandable structure 122 may include a w ire. Referring to FIGS. 1A-1B, in the deployed configuration, each w ire may form a framed protrusion that extends away from the intermediate segment 114 near the cannula blood flow exit port 112. Each framed protrusion may longitudinally span a portion of the intermediate segment 114 in which the cannula blood flow exit port 112 is formed. That is, the wire of each expandable structure 122 may first extend away from the intermediate segment 114 at a location proximal to the cannula blood flow exit port 112. Each wire may then bend back around and return to (or at least near) the intermediate segment 114 at a location distal to the cannula blood flow exit port 112. The two framed protrusions may be positioned on opposing sides of the cannula blood flow exit port 112.

[0075] The longitudinal spanning and the placement on opposing sides of the cannula blood flow exit port 112 by the framed protrusions of the expandable structures 122 essentially creates a gap or space around the cannula blood flow exit port 112. This gap or space may be filled with, e.g., blood. However, larger objects, such as a vessel sidewall, cannot enter the gap or space formed by the framed protrusions. By ensuring a clear gap or space around the cannula blood flow exit port 112, the cannula blood flow exit port 112 is less likely to be occluded, e.g., by the vessel sidewall. Thus, the expandable structures 122 may inhibit occlusion of the cannula blood flow exit port 112, e.g., by the vessel sidew all, to ensure blood perfusion (or at least improve a likelihood of acceptable blood perfusion) dow nstream of the cannula blood flow exit port 112 and in an opposite direction from the blood flow exiting the distal end 106 of the cannula too.

[0076] By using a shape memory material for the expandable structures 122, the expandable portions 122A may be compressed into the tubes 120 for insertion while returning to a desired shape that includes the framed protrusions around the cannula blood flow exit port 112 when deployed from the tubes 120. By keeping the expandable portions 122A compressed within the tubes 120 for insertion, a profile of the cannula too may be kept as small as possible to limit trauma when inserting the cannula too. After insertion into the vessel and deployment of the expandable portions 122A to their expanded state, the expanded expandable portions 122A create an anchor to keep the cannula too in place within the vessel (specifically the first segment 116 and part of the intermediate segment 114 within the vessel).

[0077] FIG. 3 is a cross-sectional side view of the cannula too inserted into a blood vessel 300, arranged in accordance with at least one embodiment herein. As illustrated, the cannula too has been inserted into the blood vessel 300 through an incision 302 having a width wi that is about equal to (or slightly larger than) a width of the cannula too when the retainer 104 is in the stowed configuration. After deploying the retainer 104, e.g., afterdeploying the expandable structures 122, the cannula too has a wi th w2 that is larger than the w idth wl of the incision. The expandable structures 122 thereby anchor the cannula too to the blood vessel 300 as any pull on the cannula too, unintentional or otherwise, to remove it from the blood vessel 300 with the retainer 104 deployed will cause the retainer 104 and the distal segment 116 of the cannula too to engage the blood vessel 300 and resist removal.

[0078] FIG. 3 further includes various block arrows to indicate the general flow of blood through and out of the lumen 110 of the cannula too and the blood vessel 300 in operation. Most of the blood may flow out the distal end 106 of the cannula too and in a first direction through the blood vessel 300 (e.g., retrograde if the blood vessel 300 is the femoral artery). In addition, some of the blood may flow out of the cannula too through the cannula blood flow exit port 112 in a second direction (opposite to the first direction) through the blood vessel 300 (e.g., antegrade if the blood vessel 300 is the femoral artery ).

[0079] As illustrated in FIG. 3, the framed protrusions formed by the expandable structures 122 create the gap or space around the cannula blood flow exit port 112 to inhibit occlusion of the cannula blood flow exit port 112, e.g., by a sidewall of the blood vessel 300. In addition, the framed protrusions may ensure, or at least improve a likelihood of, proper positioning of the cannula too within the blood vessel 300 as the expandable structures 122 may be unable to deploy or completely deploy if the cannula too is inserted too far into the blood vessel 300 to the point that the intermediate segment 114 is flush against the blood vessel 300 sidewall. The deployed expandable structures 122 may also inhibit rotation of the cannula too relative to the blood vessel 300 about a longitudinal axis of the blood vessel 300 as the deployed expandable structures 122 may engage against a sidewall of the blood vessel 300 in response to an applied torque to inhibit rotation.

[0080] In some embodiments, and prior to removal of the cannula too from the blood vessel 300, the expandable structures 122, and particularly the expandable portions 122A of the expandable structures 122, may be withdrawn back into the tubes 120. For example, although not illustrated in FIGS. 1A-1B and 3, the expandable structures 122 may include proximal ends that extend beyond the proximal ends of the tubes 120 when in the deployed configuration and a user may pull the proximal ends proximally to force the expanded expandable portions 122A back into the tubes 120.

[0081] FIGS. 4A-4B depict another example bidirectional cannula 400, arranged in accordance with at least one embodiment described herein. FIG. 4A depicts the entire cannula 400 and FIG. 4B is a detail view’ of a portion of the cannula 400. As illustrated in FIGS. 4A-4B, the cannula 400 includes a cannula body 402 and a balloon 404 coupled to the cannula body 402. A portion of the cannula body 402 that passes through the balloon 404 is depicted in dashed lines to indicate that it is inside the balloon 404 (and may or maynot be visible), but the cannula body 402 may in some embodiments be visible within the balloon 404, e.g., if the balloon is optically transparent.

[0082] The cannula body 402 is elongated and hollow and has a distal end 406 and a proximal end 408 that are both open, the cannula body 402 defining a lumen 410 that extends from the distal end 406 to the proximal end 408. The cannula body 402 also includes one or more cannula blood flow exit ports 412 formed in the cannula body 402 adjacent to the distal end 406. In this example, “adjacent to the distal end 406” may mean with i n 40 mm, 30 mm, 20 mm, or 10 mm of the distal end 406. More generally, the cannula blood flow exit ports 412 may be formed in a portion of the cannula body 402 that is encompassed by the balloon 404. Although a single cannula blood flow exit port 412 is depicted as encompassed by the balloon 404 in FIG. 4A (or adjacent to the distal end 406), more generally the cannula 400 may include any number of cannula blood flow exit ports 412 encompassed by the balloon 404 (or adjacent to the distal end 406), such as two, three, four, or more cannula blood flow exit ports 412. When there are multiple cannula blood flow exit ports 412 encompassed by the balloon 404 (or adjacent to the distal end 406), the cannula blood flow exit ports 412 may be angularly spaced around the cannula body 402 and / or may be longitudinally spaced along the cannula body 402. For four cannula blood flow exit ports 412, for instance, two may be formed at a first longitudinal location along the cannula body 402 but on opposite sides from each other, e.g., angularly spaced around the cannula body 402 by 180 degrees, and the other two may be formed at a different second longitudinal location along the cannula body 402 but on opposite sides from each other. In this and other embodiments, the second set of two cannula blood flow exit ports 412 may have the same angular positions around the cannula body 402 as the first set of two cannula blood flow’ exit ports 412 or may be angularly offset therefrom, e.g., by 90 degrees or other amount.

[0083] In some embodiments, the distal end 406 of the cannula 400 may include an opening 409 that is larger in size than the one or more cannula blood flow exit ports 412, in the aggregate. Such a configuration of opening and port sizes may facilitate a higher volume of blood flowing from the distal end 406 of the cannula 400 in a corresponding direction within a blood vessel than from the one or more cannula blood flow exit ports 412 in the opposite direction within the blood vessel.

[0084] The balloon 404 is coupled to the cannula body 402 adjacent to the distal end 406 with the cannula body 402 passing through the balloon 404 and is in fluid communication with the cannula blood flow’ exit ports 412 and thereby with the lumen 410 of the cannula 400. Analogous to the cannula blood flow exit port 412, the balloon 404 being “adjacent to the distal end 406” may mean the balloon 404, or at least its most distal end, iswithin 40 mm, 30 mm, 20 mm, or 10 mm of the distal end 406. The balloon 404 may be covered in bumps or other texture or may be smooth. Providing bumps or other texture on the balloon 404 may increase friction between the balloon 404 and, e.g., a vessel’s sidewalls, to inhibit movement between the cannula 400 and the vessel. Alternatively or additionally, inflation of the balloon 404 within the vessel may provide a radial force to expand the vessel and allow’ for greater perfusion flow.

[0085] The balloon 404 may be coupled to the cannula body 402 in any suitable manner. For example, the balloon 404 may be thermally bonded to the cannula body 402, solvent bonded to the cannula body 402, or coupled to the cannula body 402 in any other suitable manner. In the illustrated example, the balloon 404 may include a distal end 414 and a proximal end 416, each of which surrounds the cannula body 402 and is bonded or otherwise coupled to the cannula body 402.

[0086] The balloon 404 includes a proximal surface 418 that faces at least partially proximally and the proximal surface 418 defines one or more balloon blood flow exit ports 420. When there are multiple balloon blood flow exit ports 420, the balloon blood flow exit ports 420 may be spaced around the balloon 404 (on the proximal surface 418) and / or may be longitudinally spaced along the balloon 404. In the example illustrated in FIGS. 4A-4B, the balloon 404 includes three balloon blood flow exit ports 420 (only tw o of which are visible in FIGS. 4A-4B) equally angularly spaced around the balloon 404. For example, each of the three balloon blood flow exit ports 420 may be 120 degrees offset from each of the other two adjacent balloon blood flow exit ports 420. In other embodiments, the balloon blood flow exit ports 420 may be unequally angularly spaced around the balloon 404, may be longitudinally offset from each other, and / or may have any desired angular and / or longitudinal arrangement.

[0087] In some embodiments, the one or more cannula blood flow exit ports 412 may be at least as large, in the aggregate, as the one or more balloon blood flow exit ports 420, in the aggregate. Such a configuration of port sizes may generate positive pressure within the balloon 404 to facilitate expansion of the balloon 404 within the blood vessel. Expansion or inflation of the balloon 404 within the blood vessel may better retain the cannula 400 at a desired location within the blood vessel as the inflated balloon may engage sidewalls of the blood vessel. Alternatively or additionally, more positive pressure within the balloon 404 and / or the expanded / inflated balloon 404 may increase a velocity of blood flowing from the balloon 404 compared to the balloon 404 being flaccid if the aggregate size of the balloon blood flow exit ports 420 exceeds that of the cannula blood flow exit ports 412.

[0088] In operation, blood flows through the cannula 400 by entering through the proximal end 408, traveling completely or partially through the lumen 410, and exitingthrough the distal end 406 or the cannula blood flow exit ports 412. Blood flow exiting the distal end 406 is configured to flow through the vessel in a first direction e.g., retrograde if the vessel is the femoral artery). The cannula blood flow exit ports 412 may be configured to direct blood flow into the balloon 404. As such, blood flow exiting through the cannula blood flow exit ports 412 is configured to flow into the balloon 404. Blood flow may pass through and then exit the balloon 404 through the balloon blood flow exit ports 420. The balloon blood flow exit ports 420 may be configured to direct blood flow in the opposite direction from the blood flow exiting the distal end 406. As such, blood flow exiting the balloon blood flow exit ports 420, which are facing at least partially proximally , is configured to flow through the vessel in a second direction (e.p., antegrade if the vessel is the femoral artery ) opposite to the first direction. The angular offset locations of the balloon blood flow exit ports 420 may provide multiple flow paths for blood flow to exit the balloon 404. For example, in the event one of the balloon blood flow exit ports 420 is partially or completely occluded, e.g., by the internal anatomy of the vessel, blood may still flow out of the balloon 404 through the other balloon blood flow exit ports 420 to inhibit interruption of the blood flow in the second direction within the vessel.

[0089] In some embodiments, the cannula 400 may further include one or more other cannula blood flow exit ports 422 formed in the cannula body 402 distal to the balloon 404. Although only one other cannula blood flow exit port 422 is visible in FIGS. 4A-4B, the cannula 400 may more generally include one, two, three, or even more other cannula blood flow exit ports 422 formed in the cannula body 402 distal to the balloon 404 in any suitable arrangement (e.p., with equal and / or offset angular and / or longitudinal positions). The other cannula blood flow exit ports 422 may provide additional flow paths for blood flow to exit at or near the distal end 406 of the cannula in the first direction through the vessel. In the event the distal end 406 is partially or completely occluded by the internal anatomy of the vessel, the other cannula blood flow exit ports 422 may inhibit interruption of the blood flow7in the first direction within the vessel.

[0090] Although not depicted in FIGS. 4A-4B, the cannula body 402 may be or include a body of w ire wound or braided tubing in which wound or braided w ire is formed within or around tubing. The w ire wound or braided tubing may have any suitable size, such as 15 Fr, 17 Fr, 19 Fr, or other desired size. In some embodiments, the entire cannula body 402 may include wire wound or braided tubing. In some embodiments, the cannula body 402 may include one or more wire wound or braided tubing sections and one or more tubing sections that are devoid of wire. For example, the portions of the cannula body 402 in which the cannula blood flow7exit ports 412 and / or the other cannula blood flow exit ports 422 are formed may be tubing devoid of wire. The absence of wire in the portions of the cannulabody 402 in which the cannula blood flow exit ports 412 and / or the other cannula blood flow exit ports 422 are formed may simplify manufacturing of the cannula 400. Alternatively or additionally, the cannula body 402 may include a tapered tip at the distal end 406 of a biocompatible metal or other material.

[0091] The balloon 404 may include a flexible and biocompatible material such as silicone, polyurethane, Pebax, polyethylene terephthalate (PET), expanded polytetrafluoroethylene (ePTFE), or other suitable material. The balloon 404 may be configured to expand, e.g., responsive to internal pressure from blood flow from the cannula blood flow exit ports 412. The balloon 404 may be configured to collapse against the cannula body 402 when not subject to internal pressure and / or responsive to external pressure. For example, during insertion of the cannula 400 into a vessel when there is no blood flow from the cannula body 402 into the balloon 404, the balloon 404 may be configured to collapse against the cannula body 402 as the balloon 404 mounted to the cannula body 402 passes through an incision at an insertion site. Alternatively or additionally, and during removal of the cannula 400 from the vessel when there is no blood flow from the cannula body 402 into the balloon 404, the balloon 404 may be configured to collapse against the cannula body 402 as the balloon 404 mounted to the cannula body 402 passes out through the incision at the insertion site.

[0092] FIG. 5 is a cross-sectional side view of the cannula 400 inserted into a blood vessel 500, arranged in accordance with at least one embodiment herein. As illustrated, the cannula 400 has been inserted into the blood vessel 500 through an incision 502. FIG. 5 further includes various block arrows to indicate the general flow of blood through and out of the lumen 410 of the cannula 400 and the blood vessel 500 in operation. Most of the blood may flow out the distal end 406 of the cannula 400 and / or through the other cannula blood flow exit ports 422 near the distal end 406. The blood flow out of the distal end 406 and / or the other cannula blood flow exit ports 422 may generally be in a first direction through the blood vessel 500 e.g., retrograde if the blood vessel 500 is the femoral artery). In addition, some of the blood flows out of the cannula 400 through the cannula blood flow exit ports 412, into the balloon 404, and then out the balloon 404 through the balloon blood flow exit ports 420. The blood flow out of the balloon blood flow exit ports 420 may generally be in a second direction (opposite to the first direction) through the blood vessel 500 (e.g., antegrade if the blood vessel 500 is the femoral artery).

[0093] In some embodiments, the balloon 404 may have a diameter, when fully inflated, that exceeds or is about equal to a diameter of the blood vessel 500. The balloon 404 may inflate in use up to the diameter of the blood vessel 500, even if this is less than the fully inflated diameter of the balloon 404. The balloon 404 may thereby block blood flowexternally past the balloon 404 to ensure that, or at least increase a likelihood of, blood that exits the cannula 400 through the distal end 406 and / or the other cannula blood flow exit ports 422 flows in the first direction and blood that exits the cannula 400 through the cannula blood flow exit ports 412 and the balloon blood flow exit ports 420 flows in the second direction.

[0094] FIG. 6 illustrates a prototype of the cannula 400 of FIGS. 4A-4B, arranged in accordance with at least one embodiment herein. In FIG. 6, the rototype of the cannula 400 was tested by providing water through the proximal end 408 (FIG. 4A) with the prototype in a sink. As illustrated, various flows or streams of water were outputted from the cannula 400, including a primary flow 602 outputted through the distal end 406, flows 604 outputted through the other cannula blood flow exit ports 422, and flows 606 outputted through the balloon blood flow exit ports 420. As shown, the water flows generally in two opposite directions, e.g., to the right and to the left in FIG. 6. While some of the flows 604, 606 have a vertical component to them, enclosing the prototype (e.g., within a tube to represent a blood vessel) would confine the flows to flow overall primarily in the opposite directions.

[0095] To remove the cannula 400, the cannula 400 may be pulled proximally. When not pressurized by blood flow, the balloon 404 may collapse against the cannula body 402 as it reaches and is pulled through the incision 502.

[0096] Some other cannulas include a balloon that encloses a portion of the cannula, such as described in W02020176968A1. The purpose of the balloon in these other cannulas is to seal the vessel so that blood cannot flow externally past the balloon. These other cannulas include a separate dedicated supply line to the balloon to inflate or deflate the balloon. These other cannulas do not supply blood flow into and out through the balloon itself.

[0097] FIG. 7A is a perspective -view of a bidirectional cannula assembly 700, arranged in accordance with at least one embodiment described herein. The cannula assembly 700 includes a first cannula 702 and a second cannula 704. FIG. 7B is a cross-sectional perspective view of the first cannula 702, arranged in accordance w ith at least one embodiment described herein.

[0098] As illustrated in FIGS. 7A-7B, the first cannula 702 includes a cannula body 706 that is elongated and hollow and that has a distal end 708 and a proximal end 710 that are both open. The cannula body 706 defines a first lumen 712 that extends from the distal end 708 to the proximal end 710. The cannula body 706 also defines a second lumen 714 that extends at least partially between the distal end 708 and the proximal end 710. The firstlumen 712 has a larger cross-sectional area than the second lumen 714, e.g., in a plane perpendicular to a length of the first cannula 702.

[0099] The second cannula 704 is receivable within the second lumen 714 of the first cannula 702 and is positioned in the second lumen 714 during use of the cannula assembly 700. The second lumen 714 has a turn 716 at a distal end 718 of the second lumen 714 that forces the second cannula 704 to change direction at the turn 716 where the second cannula 704 exits the second lumen 714 of the first cannula 702.

[0100] In some embodiments, the first cannula 702 includes an intermediate segment 720 that includes part of the first lumen 712 and all of the second lumen 714, a distal segment 722 that is distal to the intermediate segment 720 and includes a distal portion of the first lumen 712, and a proximal segment 724 that is proximal to the intermediate segment 720 and includes a proximal portion of the first lumen 712. An outer diameter of the distal segment 722 may be equal or approximately equal (e.g., plus or minus 10%) to an outer diameter of the intermediate segment 720. To accommodate the second lumen 714 while keeping the outer diameter of the intermediate segment 720 equal or approximately equal to the outer diameter of the distal segment 722, the first lumen 712 may have a smaller diameter in the intermediate segment 720 than in the distal segment 722.

[0101] Alternatively or additionally, the first cannula 702 may have a generally smooth and / or ramped transition 726 from the distal segment 722 to the intermediate segment 720 on an exterior of the first cannula 702. The generally smooth and / or ramped transition 726 may be less likely to catch an edge of an incision at an insertion site than an abrupt transition.

[0102] In operation, blood flows through the first cannula 702 by entering through the proximal end 710, traveling through the first lumen 712, and exiting through the distal end 708. Blood flow exiting the distal end 708 is configured to flow7through the vessel in a first direction (e.g., retrograde if the vessel is the femoral artery). Further, and with the second cannula 704 installed in the second lumen 714, blood flow7s through the second cannula 704 by entering through a proximal end 727 of the second cannula 704, traveling through a lumen (not labeled) of the second cannula 704, and exiting through a distal end 728 of the second cannula 704. The distal end 728 of the second cannula 704 may be pointed in a different direction, or may direct blood flow in a different direction, than the distal end 708 of the first cannula 702. As such, blood flow exiting the distal end 728 of the second cannula 704 is configured to flow through the vessel in a second direction (e.g., antegrade if the vessel is the femoral artery ) that is opposite to the first direction.

[0103] In some embodiments, the second cannula 704 may further include one or more cannula blood flow exit ports (not illustrated in FIG. 7A) formed in the second cannula 704 body toward the distal end 728 of the second cannula 704. For example, the cannula blood flow exit ports may be formed in a distal segment 730 that includes the distal end 728. Where there are multiple cannula blood flow exit ports, they may have any desired arrangement, such as angularly spaced around the second cannula 704 at the same longitudinal location, longitudinally spaced along the distal segment 730 at the same angular location, or both angularly and longitudinally spaced in the distal segment 730. The cannula blood flow exit ports, when present, may provide additional flow paths for blood flow’ to exit at or near the distal end 728 of the second cannula 704 in the second direction through the vessel. In the event the distal end 728 of the second cannula 704 is partially or completely occluded by the internal anatomy of the vessel, the cannula blood flow exit ports may inhibit interruption of the blood flow in the second direction within the vessel.

[0104] Although not depicted in FIGS. 7A-7B, the cannula body 706 of the first cannula 702 and / or the cannula body of the second cannula 704 may be or include a body of wire wound or braided tubing in which wound or braided wire is formed within or around tubing. For the first cannula 702, the wire wound or braided tubing may have any suitable size, such as 15 Fr, 17 Fr, 19 Fr, or other desired size. For the second cannula 704, the wdre wound or braided tubing may have any suitable size, such as 5 Fr, 6 Fr, 7 Fr, 8 Fr, 9 Fr, 10 Fr, or other desired size. In some embodiments, the entire cannula body 706 of the first cannula 702 and / or of the second cannula 704 may include wdre wound or braided tubing. In some embodiments, the cannula body 706 of the first cannula 702 and / or of the second cannula 704 may include one or more wdre wound or braided tubing sections and one or more tubing sections that are devoid of wdre.

[0105] FIG. 8 is a cross-sectional side view of the cannula assembly 700 inserted into a blood vessel 800, arranged in accordance with at least one embodiment herein. As illustrated, the cannula assembly 700 has been inserted into the blood vessel 800 through an incision 802, with the distal end 708 of the first cannula 702 facing or pointing a first direction and the distal end 728 of the second cannula 704 facing or pointing a second direction that is opposite the first direction. Further, both the first cannula 702 and the second cannula 704 are inserted into the blood vessel 800 through the same incision 802. The second cannula 704 may be inserted into the second lumen 714 of the first cannula 702 after the first cannula 702 is inserted into the blood vessel 800 through the incision 802. Alternatively, the second cannula 704 may be inserted partially into the second lumen 714 of the first cannula 702 prior to insertion where the distal end 728 of the second cannula 704 is enclosed within the second lumen 714. After insertion of the cannula assembly 700 into theblood vessel 800, the second cannula 704 may be further advanced in the second lumen 714 until the distal end 728 of the second cannula 704 extends out of the second lumen 714 into the blood vessel 800 as generally illustrated in FIG. 8.

[0106] FIG. 8 further includes various block arrows to indicate the flow of blood through both the first lumen 712 of the first cannula 702 and the lumen of the second cannula 704 in operation. Blood flowing through the first lumen 712 of the first cannula 702 flows out the distal end 708 of the first cannula 702 in the first direction. The blood flow out of the distal end 708 of the first cannula 702 may generally be in the first direction (e.g., retrograde if the blood vessel 800 the femoral artery). Blood flowing through the lumen of the second cannula 704 flows out the distal end 728 of the second cannula 704 in the second direction. The blood flow out of the distal end 728 of the second cannula 704 may generally be in the second direction (opposite to the first direction) through the blood vessel 800 (e.g., antegrade if the blood vessel 800 is the femoral artery).

[0107] The second cannula 704 may be inserted any desired depth into the blood vessel 800. In embodiments in which the second cannula 704 includes one or more cannula blood flow exit ports in the distal segment 730, the second cannula may be advanced through the second lumen 714 of the first cannula 702 and into the blood vessel at least to the point that all of the cannula blood flow exit ports are positioned within the blood vessel 800. In some embodiments, after insertion into the blood vessel 800 to the point that a portion of the first cannula 702 (e.g., the distal segment 722) is fully within the blood vessel 800 to one side of the incision 802 and a portion of the second cannula 704 (e.g., the distal segment 730) is fully within the blood vessel 800 to the opposite side of the incision 802, the first cannula 702 and the second cannula 704 create an anchor to keep the cannula assembly 700 (specifically at least the distal segment 722 of the first cannula 702 and the distal segment 730 of the second cannula 704 within the blood vessel 800. In particular, with the cannula assembly 700 arranged generally as illustrated in FIG. 8, any pull on the cannula too, unintentional or otherwise, to remove it from the blood vessel 800 will cause the distal segment 722 of the first cannula and the distal segment 730 of the second cannula 704 to engage the blood vessel 300 and resist removal.

[0108] The first lumen 712 of the first cannula 702 and the lumen of the second cannula 704 may be in fluid communication with a common perfusion source (or blood flow source) such that they both supply blood flow into the blood vessel 800 in a corresponding direction.

[0109] The first lumen 712 of the first cannula 702 may have a larger diameter (at the intermediate segment 720, the distal segment 722, and the proximal segment 724) than the lumen of the second cannula 704. Such a configuration of diameters of the lumens may facilitate a higher volume of blood flowing from the distal end 708 of the first cannula 702 ina corresponding direction within the blood vessel 800 than from the distal end 728 of the second cannula 704 in the opposite direction within the blood vessel 800.

[0110] FIGS. 9A-9B depict another example bidirectional cannula 900, arranged in accordance with at least one embodiment described herein. FIG. 9A depicts the entire cannula 900 and FIG. 9B is a detail view of a portion of the cannula 900. As illustrated in FIGS. 9A-9B, the cannula 900 includes a cannula body 902 and a balloon 904 coupled to the cannula body 902. The cannula body 902 and balloon 904 are depicted as transparent in FIGS. 9A-9B such that a portion of the cannula body 902 that passes through the balloon 904 is visible within the balloon 904. The cannula body 902 and / or the balloon 904 may be optically opaque or optically transparent in practice, or a combination of the two (e.g., some parts may be opaque while other parts may be transparent).

[0111] The cannula body 902 is elongated and hollow and has a distal end 906 and a proximal end 908 that are both open, the cannula body 902 defining a lumen 910 that extends from the distal end 906 to the proximal end 908. The cannula body 902 also includes one or more cannula blood flow exit ports 912 formed in the cannula body 902 adjacent to the distal end 906. In this example, “adjacent to the distal end 906” may mean within 40 mm, 30 mm, 20 mm, or 10 mm of the distal end 906. More generally, the cannula blood flow exit ports 912 may be formed in a portion of the cannula body 902 that is encompassed by the balloon 904. A single cannula blood flow exit port 912 is visible in FIG. 9A encompassed by the balloon 904 in FIG. 9A (or adjacent to the distal end 906) and three cannula blood flow exit ports 912 are visible in FIG. 9B encompassed by the balloon 904 in FIG. 9B. More generally, the cannula 900 may include any number of cannula blood flow exit ports 912 encompassed by the balloon 904 (or adjacent to the distal end 906), such as one, two, three, four, or more cannula blood flow exit ports 912. When there are multiple cannula blood flow exit ports 912 encompassed by the balloon 904 (or adjacent to the distal end 906), the cannula blood flow exit ports 912 may be angularly spaced around the cannula body 902 and / or may be longitudinally spaced along the cannula body 902. For four cannula blood flow exit ports 912, for instance, all four may be formed at the same longitudinal location along the cannula body 902 but angularly spaced around the cannula body 902, e.g., by 90 degrees. As another example involving four cannula blood flow exit ports 912, two may be at one longitudinal location along the cannula body 902 and angularly offset from each other by, e.g., 180 degrees, while two others may be at another longitudinal location and angularly offset from each other by, e.g., 180 degrees.

[0112] The balloon 904 is coupled to the cannula body 902 adjacent to the distal end 906 with the cannula body 902 passing through the balloon 904 and is in fluid communication with the cannula blood flow exit ports 912 and thereby with the lumen 910 ofthe cannula 900. Analogous to the cannula blood flow exit port 912, the balloon 904 being “adjacent to the distal end 906” may mean the balloon 904, or at least its most distal end, is within 40 mm, 30 mm, 20 mm, or 10 mm of the distal end 906. The balloon 904 may be covered in bumps or other texture or may be smooth. Providing bumps or other texture on the balloon 904 may increase friction between the balloon 904 and, e.g., a vessel’s sidewalls, to inhibit movement between the cannula 900 and the vessel. Alternatively or additionally, inflation of the balloon 904 with i n the vessel may provide a radial force to expand the vessel and allow’ for greater perfusion flow.

[0113] The balloon 904 may be coupled to the cannula body 902 in any suitable manner. For example, the balloon 904 may be thermally bonded to the cannula body 902, solvent bonded to the cannula body 902, or coupled to the cannula body 902 in any other suitable manner. In the illustrated example, the balloon 904 may include a distal end 914 and a proximal end 916, each of which surrounds the cannula body 902 and is bonded or otherwise coupled to the cannula body 902.

[0114] The balloon 904 includes a proximal surface 918 that faces at least partially proximally and the proximal surface 918 defines one or more balloon blood flow exit ports 920. When there are multiple balloon blood flow exit ports 920, the balloon blood flow exit ports 920 may be spaced around the cannula body 902 (on or in the proximal surface 918 of the balloon 904) and / or may be longitudinally spaced along the balloon 904. In the example illustrated in FIGS. 9A-9B, the balloon 904 includes four balloon blood flow exit ports 920 (each of which is at least partially visible in FIG. 9B) equally angularly spaced in the balloon 904 around the cannula body 902. For example, the balloon blood flow exit ports 920 may be 90 degrees offset from each other around the cannula body 902 in the proximal surface 918 of the balloon 904. In other embodiments, the balloon blood flow exit ports 920 may be unequally angularly spaced around the cannula body 902, may be longitudinally offset from each other, and / or may have any desired angular and / or longitudinal arrangement.

[0115] In operation, blood flows through the cannula 900 by entering through the proximal end 908, traveling completely or partially through the lumen 910, and exiting through the distal end 906 or the cannula blood flow exit ports 912. Blood flow- exiting the distal end 906 is configured to flow through the vessel in a first direction e.g., retrograde if the vessel is the femoral artery). The cannula blood flow exit ports 912 may be configured to direct blood flow into the balloon 904. As such, blood flow exiting through the cannula blood flow exit ports 912 is configured to flow into the balloon 904. Blood flow may pass through and then exit the balloon 904 through the balloon blood flow exit ports 920. The balloon blood flow exit ports 920 may be configured to direct blood flow in the opposite direction from the blood flow exiting the distal end 906, e.g., by virtue of the balloon blood flow exitports 920 being formed in the proximal surface 918 of the balloon 904. As such, blood flow exiting the balloon blood flow exit ports 920, which are facing at least partially proximally, is configured to flow’ through the vessel in a second direction (e.g., antegrade if the vessel is the femoral artery ) opposite to the first direction. The angular offset locations of the balloon blood flow’ exit ports 920 may provide multiple flow’ paths for blood flow to exit the balloon 904. For example, in the event one of the balloon blood flow’ exit ports 920 is partially or completely occluded, e.g., by the internal anatomy’ of the vessel, blood may still flow out of the balloon 904 through the other balloon blood flow exit ports 920 to inhibit interruption of the blood flow in the second direction within the vessel.

[0116] In some embodiments, the distal end 906 of the cannula 900 may include an opening 909 that is larger in size than the one or more cannula blood flow exit ports 912, in the aggregate. Such a configuration of opening and port sizes may facilitate a higher volume of blood flowing from the distal end 906 of the cannula 900 in a corresponding direction within a blood vessel than from the one or more cannula blood flow exit ports 912 and balloon blood flow exit ports 920 in the opposite direction within the blood vessel. The foregoing may apply, with appropriate changes, to other cannulas disclosed herein, including the cannulas of FIGS. 10A-14B.

[0117] In embodiments that include a balloon, including FIGS. 9A-9B and other embodiments herein, a cumulative or aggregate area of the cannula blood flow exit ports 912 within the balloon 904 may exceed a cumulative or aggregate area of the balloon blood flow exit ports 920. The difference in cumulative area may ensure, or at least increase a likelihood, that a positive pressure is created by blood flow into and through the balloon 904. Such positive pressure may drive inflation of the balloon 904 w hile still allow ing blood flow out of the balloon 904 in the second direction within the vessel. Expansion or inflation of the balloon 904 within the blood vessel may better retain the cannula 900 at a desired location within the blood vessel as the inflated balloon may engage sidewalls of the blood vessel. Alternatively7or additionally, more positive pressure within the balloon 904 and / or the inflated balloon 904 may increase a velocity of blood flowing from the balloon 904 compared to the balloon 904 being flaccid if the aggregate size of the balloon blood flow exit ports 920 exceeds that of the cannula blood flow7exit ports 912.

[0118] In some embodiments, the cannula 900 may further include one or more other cannula blood flow exit ports 922 formed in the cannula body 902 distal to the balloon 904. Although only one other cannula blood flow exit port 922 is visible in FIGS. 9A-9B, the cannula 900 may more generally include one, two, three, or even more other cannula blood flow exit ports 922 formed in the cannula body 902 distal to the balloon 904 in any suitable arrangement (e.g., with equal and / or offset angular and / or longitudinal positions). Theother cannula blood flow exit ports 922 may provide additional flow paths for blood flow to exit at or near the distal end 906 of the cannula in the first direction through the vessel. In the event the distal end 906 is partially or completely occluded by the internal anatomy of the vessel, for example, the other cannula blood flow exit ports 922 may inhibit interruption of the blood flow in the first direction within the vessel.

[0119] As illustrated in FIGS. 9A-9B, the cannula body 902 may be or include a body of w ire wound or braided tubing in which wound or braided wire is formed within or around tubing. The wire wound or braided tubing may have any suitable size, such as 15 Fr, 17 Fr, 19 Fr, or other desired size. In some embodiments, the entire cannula body 902 may include wire wound or braided tubing. In some embodiments, the cannula body 902 may include one or more wire wound or braided tubing sections and one or more tubing sections that are devoid of wire. For example, the portions of the cannula body 902 in which the cannula blood flow exit ports 912 and / or the other cannula blood flow exit ports 922 are formed may be tubing devoid of wire. The absence of wire in the portions of the cannula body 902 in w hich the cannula blood flow exit ports 912 and / or the other cannula blood flow- exit ports 922 are formed may simplify manufacturing of the cannula 900. Alternatively or additionally, the cannula body 902 may include a tapered tip at the distal end 906 of a biocompatible metal or other material.

[0120] The balloon 904 may include a flexible and biocompatible material such as silicone, polyurethane, polyether block amide (PEBA, e.g., PEBAX® polyether block amide; Arkema), PET, ePTFE, or other suitable material. The balloon 904 may be configured to expand, e.g., responsive to internal pressure from blood flow from the cannula blood flow exit ports 912. The balloon 904 may be configured to collapse against the cannula body 902 w-hen not subject to internal pressure and / or responsive to external pressure. For example, during insertion of the cannula 900 into a vessel when there is no blood flow- from the cannula body 902 into the balloon 904, the balloon 904 may be configured to collapse against the cannula body 902 as the balloon 904 mounted to the cannula body 902 passes through an incision at an insertion site into the vessel. Alternatively or additionally, and during removal of the cannula 900 from the vessel when there is no blood flowrfrom the cannula body 902 into the balloon 904, the balloon 904 may be configured to collapse against the cannula body 902 as the balloon 904 mounted to the cannula body 902 passes out through the incision at the insertion site.

[0121] FIG. 9A further depicts an example cannula hub 924 that includes an output port 926 coupled into the proximal end 908 of the cannula 900 and two input ports 928, 930. As will be described in more detail, the two input ports 928, 930 may permit simultaneous coupling of the proximal end 908 of the cannula 900 to both a perfusion source through oneof the input ports 928, 930 and to a valve assembly through the other of the input ports 930, 928. The valve assembly may permit introduction of intravascular catheters into the vessel through the cannula 900. Examples of intravascular catheters include PCI balloons, coronary stent delivery systems, intra-aortic balloon pumps, and the like. The cannula hub 924 may be used with any of the cannulas or other systems, devices, or assemblies described herein.

[0122] In some embodiments, the balloon 904 may be primed (e.g., have air inside of the balloon removed and / or pushed out). In some embodiments, priming the balloon 904 may include introducing one or more priming fluids to the balloon 904. For example, one or more valve assemblies and / or input ports (e.g., input ports 928, 930) may be used to introduce priming fluid into the balloon 904. More generally, any of the cannulas described herein that include a balloon may be primed. Various example primer del ivery paths through such cannulas herein are described in, e.g., FIGS. 16A-16C.

[0123] In some embodiments, the cannula hub 924 may include one or more antirotation features such as a flange between the output port 926 and the two input ports 928, 930. In these and other embodiments, the flange may be configured to contact tissue of a patient at an insertion site of the cannula 900 to inhibit rotation of the cannula 900 while the cannula 900 is inserted in the patient. In some embodiments, the flange may be made of a semi-rigid material. A semi-rigid material may include any material that exhibits a defined shape under typical physiological loads while retaining the flexibility to conform partially to anatomical surfaces and accommodate partial deformation without fracturing or moving from an intended positioning. For example, the flange may include polycarbonate, polyethylene terephthalate (PET), acrylonitrile butadiene styrene (ABS), and / or any other semi-rigid material. Additionally or alternatively, the flange may be made of an adhesive material. An adhesive material may include any material that is capable of adhering two surfaces together by forming an interface with sufficient bonding strength to resist separation under expected physiological loads. For example, the flange may include a silicone adhesive, an aciylic-based adhesive, a cyanoacrylate adhesive, and / or any other adhesive material.

[0124] In some embodiments, the flange may be integrally formed with the cannula hub 924. In these and in other embodiments, the flange may include one or more flange holes configured for placement of sutures between the flange and the tissue of the patient through the flange holes. Each of the flange holes may have a size and shape suitable for accommodating standard surgical suture needles and suture material. In some embodiments, the flange holes may be positioned at locations along the flange that may assist in fixing the cannula 900 at the insertion site. In some embodiments, the numberand / or spacing of the flange holes may be selected to distribute retention forces, which may reduce the likelihood of local tissue trauma during and / or after suture placement through the flange holes.

[0125] FIGS. 10A-10B depict another example bidirectional cannula 1000, arranged in accordance with at least one embodiment described herein. FIG. 10A depicts the entire cannula 1000 and FIG. 10B is a detail view of a portion of the cannula 1000. As illustrated in FIGS. 10A-10B, the cannula 1000 includes a cannula body 1002 and a balloon 1004 coupled to the cannula body 1002. The cannula body 1002 and balloon 1004 are depicted as transparent in FIGS. 10A-10B such that a portion of the cannula body 1002 that passes through the balloon 1004 is visible within the balloon 1004. The cannula body 1002 and / or the balloon 1004 may be optically opaque or optically transparent in practice, or a combination of the two (e.g., some parts may be opaque while other parts may be transparent).

[0126] The cannula body 1002 is elongated and hollow and has a distal end 1006 and a proximal end 1008 that are both open, the cannula body 1002 defining a lumen 1010 that extends from the distal end 1006 to the proximal end 1008. The cannula body 1002 also includes one or more cannula blood flow exit ports 1012 formed in the cannula body 1002 at an intermediate location of the cannula body 1002 that is spaced apart from the proximal end 1008 and the distal end 1006. In this example, “spaced apart from the proximal end 1008 and the distal end 1006” may mean at least 40 mm, 50 mm, 60 mm, 70 mm, or more between the cannula blood flow exit ports 1012 and each of the proximal end 1008 and the distal end 1006. More generally, the cannula blood flow exit ports 1012 may be formed in a portion of the cannula body 1002 that is encompassed by the balloon 1004. A single cannula blood flow exit port 1012 is visible in FIG. 10A encompassed by the balloon 1004 in FIG. 10A (at the intermediate location of the cannula body 1002) and three cannula blood flow exit ports 1012 are visible in FIG. 10B encompassed by the balloon 1004 in FIG. 10B. More generally, the cannula 1000 may include any number of cannula blood flow exit ports 1012 encompassed by the balloon 1004 (or at the intermediate location), such as one, two, three, four, or more cannula blood flow exit ports 1012. When there are multiple cannula blood flow exit ports 1012 encompassed by the balloon 1004 (or at the intermediate location), the cannula blood flow exit ports 1012 may be angularly spaced around the cannula body 1002 and / or may be longitudinally spaced along the cannula body 1002. For four cannula blood flow exit ports 1012, for instance, all four may be formed at the same longitudinal location along the cannula body 1002 but angularly spaced around the cannula body 1002, e.g., by 90 degrees. As another example involving four cannula blood flow exit ports 1012, two may be at one longitudinal location along the cannula body 1002 and angularly offset from each otherby, e.g., 180 degrees, while two others may be at another longitudinal location and angularly offset from each other by, e.g., 180 degrees.

[0127] The balloon 1004 is coupled to the cannula body 1002 at the intermediate location spaced apart from the proximal end 1008 and the distal end 1006 with the cannula body 1002 passing through the balloon 1004 and is in fluid communication with the cannula blood flow exit ports 1012 and thereby with the lumen 1010 of the cannula 1000. Analogous to the cannula blood flow exit port 1012, the balloon 1004 being “spaced apart from the proximal end 1008 and the distal end 1006” may mean the balloon 1004 is at least 40 mm, 50 mm, 60 mm, 70 mm, or more from each of the proximal end 1008 and the distal end 1006. The balloon 1004 may be covered in bumps or other texture or may be smooth. Providing bumps or other texture on the balloon 1004 may increase friction between the balloon 1004 and, e.g., a vessel’s sidewalls, to inhibit movement between the cannula 1000 and the vessel. Alternatively or additionally, inflation of the balloon 1004 within the vessel may provide a radial force to expand the vessel and allows for greater perfusion flow.

[0128] The balloon 1004 may be coupled to the cannula body 1002 in any suitable manner. For example, the balloon 1004 may be thermally bonded to the cannula body 1002, solvent bonded to the cannula body 1002, or coupled to the cannula body 1002 in any other suitable manner. In the illustrated example, the balloon 1004 may include a distal end 1014 and a proximal end 1016, each of which surrounds the cannula body 1002 and is bonded or otherwise coupled to the cannula body 1002.

[0129] The balloon 1004 includes a proximal surface 1018 that faces at least partially proximally and the proximal surface 1018 defines one or more balloon blood flow exit ports 1020. When there are multiple balloon blood flow7exit ports 1020, the balloon blood flow exit ports 1020 may be spaced around the cannula body 1002 (on or in the proximal surface 1018 of the balloon 1004) and / or may be longitudinally spaced along the balloon 1004. In the example illustrated in FIGS. 10A-10B, the balloon 1004 includes four balloon blood flow exit ports 1020 (each of which is at least partially visible in FIG. 10B) equally angularly spaced in the balloon 1004 around the cannula body 1002. For example, the balloon blood flow exit ports 1020 may be 90 degrees offset from each other around the cannula body 1002 in the proximal surface 1018 of the balloon 1004. In other embodiments, the balloon blood flow exit ports 1020 may be unequally angularly spaced around the cannula body 1002, may be longitudinally offset from each other, and / or may have any desired angular and / or longitudinal arrangement.

[0130] In operation, blood flows through the cannula 1000 by entering through the proximal end 1008, traveling completely or partially through the lumen 1010, and exiting through the distal end 1006 or the cannula blood flow- exit ports 1012. Blood flow7exiting thedistal end 1006 is configured to flow through the vessel in a first direction (e.g., retrograde if the vessel is the femoral artery). The cannula blood flow exit ports 1012 may be configured to direct blood flow into the balloon 1004. As such, blood flow exiting through the cannula blood flow’ exit ports 1012 is configured to flow into the balloon 1004. Blood flow may pass through and then exit the balloon 1004 through the balloon blood flow exit ports 1020. The balloon blood flow exit ports 1020 may be configured to direct blood flow in the opposite direction from the blood flow exiting the distal end 1006, e.g., by virtue of the balloon blood flow’ exit ports 1020 being formed in the proximal surface 1018 of the balloon 1004. As such, blood flow exiting the balloon blood flow’ exit ports 1020, which are facing at least partially proximally, is configured to flow through the vessel in a second direction (e.g., antegrade if the vessel is the femoral artery) opposite to the first direction. The angular offset locations of the balloon blood flow exit ports 1020 may provide multiple flow paths for blood flow to exit the balloon 1004. For example, in the event one of the balloon blood flow- exit ports 1020 is partially or completely occluded, e.g., by’ the internal anatomy of the vessel, blood may still flow out of the balloon 1004 through the other balloon blood flow exit ports 1020 to inhibit interruption of the blood flow in the second direction within the vessel.

[0131] In some embodiments, the cannula 1000 may further include one or more other cannula blood flow exit ports 1022 formed in the cannula body 1002 distal to the balloon 1004, e.g., at or near the distal end 1006. Although only one other cannula blood flow exit port 1022 is visible in FIGS. 10A-10B, the cannula 1000 may more generally include one, two, three, or even more other cannula blood flow exit ports 1022 formed in the cannula body 1002 distal to the balloon 1004 in any suitable arrangement (e.g., with equal and / or offset angular and / or longitudinal positions). The other cannula blood flow’ exit ports 1022 may provide additional flow paths for blood flow’ to exit at or near the distal end 1006 of the cannula in the first direction through the vessel. In the event the distal end 1006 is partially or completely’ occluded by the internal anatomy of the vessel, for example, the other cannula blood flow’ exit ports 1022 may’ inhibit interruption of the blood flow in the first direction within the vessel.

[0132] As illustrated in FIGS. 10A-10B, the cannula body' 1002 may be or include a body of wire w ound or braided tubing in which wound or braided wire is formed w ith i n or around tubing. The wire wound or braided tubing may have any suitable size, such as 15 Fr, 17 Fr, 19 Fr, or other desired size. In some embodiments, the entire cannula body 1002 may include wire wound or braided tubing. In some embodiments, the cannula body 1002 may include one or more wire wound or braided tubing sections and one or more tubing sections that are devoid of wire. For example, the portions of the cannula body 1002 in which the cannula blood flow exit ports 1012 and / or the other cannula blood flow exit ports 1022 are formedmay be tubing devoid of wire. The absence of wire in the portions of the cannula body 1002 in which the cannula blood flow exit ports 1012 and / or the other cannula blood flow exit ports 1022 are formed may simplify manufacturing of the cannula 1000. Alternatively or additionally, the cannula body 1002 may include a tapered tip at the distal end 1006 of a biocompatible metal or other material.

[0133] The balloon 1004 may include a flexible and biocompatible material such as silicone, polyurethane, Pebax, PET, ePTFE, or other suitable material. The balloon 1004 may be configured to expand, e.g., responsive to internal pressure from blood flow from the cannula blood flow- exit ports 1012. The balloon 1004 may be configured to collapse against the cannula body 1002 when not subject to internal pressure and / or responsive to external pressure. For example, during insertion of the cannula 1000 into a vessel when there is no blood flow from the cannula body 1002 into the balloon 1004, the balloon 1004 may be configured to collapse against the cannula body 1002 as the balloon 1004 mounted to the cannula body 1002 passes through an incision at an insertion site into the vessel.Alternatively or additionally, and during removal of the cannula 1000 from the vessel w hen there is no blood flow from the cannula body 1002 into the balloon 1004, the balloon 1004 may be configured to collapse against the cannula body 1002 as the balloon 1004 mounted to the cannula body 1002 passes out through the incision at the insertion site.

[0134] FIGS. 10A-10B further depict the cannula hub 924 that includes the output port 926 coupled into the proximal end 1008 of the cannula 1000 and the two input ports 928, 930. As in FIG. 9A, the two input ports 928, 930 may permit simultaneous coupling of the proximal end 1008 of the cannula 1000 to both a perfusion source through one of the input ports 928, 930 and to a valve assembly through the other of the input ports 930, 928. The valve assembly may permit introduction of intravascular catheters into the vessel through the cannula 1000.

[0135] FIGS. 11A-11B depict another example bidirectional cannula 1100, arranged in accordance with at least one embodiment described herein. FIG. 11A depicts the entire cannula 1100 and FIG. 11B is a detail new of a portion of the cannula 1100. As illustrated in FIGS. 11A-11B, the cannula 1100 includes a cannula body 1102 and a balloon 1104 coupled to the cannula body 1102. The cannula body 1102 and balloon 1104 are depicted as transparent in FIGS. 11A-11B such that a portion of the cannula body 1102 that passes through the balloon 1104 is visible within the balloon 1104. The cannula body 1102 and / or the balloon 1104 may be optically opaque or optically transparent in practice, or a combination of the two e.g., some parts may be opaque while other parts may be transparent).

[0136] The cannula body 1102 is elongated and hollow and has a distal end 1106 and a proximal end 1108 that are both open, the cannula body 1102 defining a lumen 1110 thatextends from the distal end 1106 to the proximal end 1108. The cannula body 1102 also includes one or more cannula blood flow exit ports 1112 formed in the cannula body 1102 at an intermediate location of the cannula body 1102 that is spaced apart from the proximal end 1108 and the distal end 1106. In this example, “spaced apart from the proximal end 1108 and the distal end 1106” may mean at least 40 mm, 50 mm, 60 mm, 70 mm, or more between the cannula blood flow exit ports 1112 and each of the proximal end 1108 and the distal end 1106. More generally, the cannula blood flow exit ports 1112 may be formed in a portion of the cannula body 1102 that is encompassed by the balloon 1104. A single cannula blood flow exit port 1112 is visible in FIGS. 11A-11B encompassed by the balloon 1104 (at the intermediate location of the cannula body 1102). More generally, the cannula 1100 may include any number of cannula blood flow exit ports 1112 encompassed by the balloon 1104 (or at the intermediate location), such as one, two, three, four, or more cannula blood flow exit ports 1112. When there are multiple cannula blood flow exit ports 1112 encompassed by the balloon 1104 (or at the intermediate location), the cannula blood flow exit ports 1112 may be angularly spaced around the cannula body 1102 and / or may be longitudinally spaced along the cannula body 1102. For four cannula blood flow exit ports 1112, for instance, all four may be formed at the same longitudinal location along the cannula body 1102 but angularly spaced around the cannula body 1102, e.g., by 90 degrees. As another example involving four cannula blood flow exit ports 1112, two may be at one longitudinal location along the cannula body 1102 and angularly offset from each other by, e.g., 180 degrees, while two others may be at another longitudinal location and angularly offset from each other by, e.g., 180 degrees.

[0137] The balloon 1104 is coupled to the cannula body 1102 at the intermediate location spaced apart from the proximal end 1108 and the distal end 1106 with the cannula body 1102 passing through the balloon 1104 and is in fluid communication with the cannula blood flow exit ports 1112 and thereby with the lumen 1110 of the cannula 1100. Analogous to the cannula blood flow exit port 1112, the balloon 1104 being “spaced apart from the proximal end 1108 and the distal end 1106” may mean the balloon 1104 is at least 40 mm, 50 mm, 60 mm, 70 mm, or more from each of the proximal end 1108 and the distal end 1106. The balloon 1104 may be covered in bumps or other texture or may be smooth. Providing bumps or other texture on the balloon 1104 may increase friction between the balloon 1104 and, e.g., a vessel’s sidew alls, to inhibit movement between the cannula 1100 and the vessel.

[0138] In the illustrated example, the balloon 1104 is an eccentric balloon. In particular, while the balloon 1104 completely surrounds the cannula body 1102 at the intermediate location, it is eccentrically disposed relative to the cannula body 1102 with a greater volume of the balloon 1104, or an eccentric lobe, being disposed to one side of the cannula body 1102 than to any other side of the cannula body 1102. In comparison, some other balloonsdescribed herein, such as the balloons 404, 904, 1004, are generally disposed concentrically around the corresponding cannula body (e.g., 402, 902, 1002) to which they are coupled. The eccentric disposition of the balloon 1104 relative to the cannula body 1102 may serve as a retention mechanism as described in more detail with respect to FIG. 12. Alternatively or additionally, the balloon 1104 and / or other balloons described herein may be blow molded, dip molded, or formed in any other suitable manner.

[0139] The balloon 1104 may be coupled to the cannula body 1102 in any suitable manner. For example, the balloon 1104 may be thermally bonded to the cannula body 1102, solvent bonded to the cannula body 1102, or coupled to the cannula body 1102 in any other suitable manner. In the illustrated example, the balloon 1104 may include a distal end 1114 and a proximal end 1116, each of which surrounds the cannula body 1102 and is bonded or otherwise coupled to the cannula body 1102.

[0140] The balloon 1104 includes a proximal surface 1118 that faces at least partially proximally and the proximal surface 1118 defines one or more balloon blood flow exit ports 1120. In use, the proximal surface 1118 may more generally be a surface that faces an opposite direction from the distal end 1106 of the cannula 1100. When there are multiple balloon blood flow exit ports 1120, the balloon blood flow exit ports 1120 may have any desired arrangement on the balloon 1104 and may face at least partially in the opposite direction from the distal end 1106 in use. In the example illustrated in FIGS. 11A-11B, the balloon 1104 includes one balloon blood flow exit port 1120.

[0141] In operation, blood flows through the cannula 1100 by entering through the proximal end 1108, traveling completely or partially through the lumen 1110, and exiting through the distal end 1106 or the cannula blood flow exit port 1112. Blood flow exiting the distal end 1106 is configured to flow through the vessel in a first direction (e.g., retrograde if the vessel is the femoral artery). The cannula blood flow exit ports 1112 may be configured to direct blood flow into the balloon 1104. As such, blood flow exiting through the cannula blood flow exit ports 1112 is configured to flow7into the balloon 1104. Blood flow may pass through and then exit the balloon 1104 through the balloon blood flow exit port 1120. The balloon blood flow exit port 1120 may be configured to direct blood flow in the opposite direction from the blood flow exiting the distal end 1106, e.g., by virtue of the balloon blood flow exit port 1120 being formed in the proximal surface 1118 of the balloon 1104 and facing the opposite direction from the distal end 1106 in use. As such, blood flow exiting the balloon blood flow exit port 1120, which faces at least partially proximally in use, is configured to flow through the vessel in a second direction (e.g., antegrade if the vessel is the femoral artery) opposite to the first direction. Although FIGS. 11A-11B depict a single balloon blood flow exit port 1120, in other embodiments the balloon 1104 may include multiple balloonblood flow exit ports 1120 to provide multiple flow paths for blood flow to exit the balloon 1104 to inhibit interruption of the blood flow in the second direction within the vessel.

[0142] In some embodiments, the cannula 1100 may further include one or more other cannula blood flow exit ports 1122 formed in the cannula body 1102 distal to the balloon 1104, e.g., at or near the distal end 1106. Although only one other cannula blood flow exit port 1122 is visible in FIG. 11A, the cannula 1100 may more generally include one, two, three, or even more other cannula blood flow exit ports 1122 formed in the cannula body 1102 distal to the balloon 1104 in any suitable arrangement e.g., with equal and / or offset angular and / or longitudinal positions). The other cannula blood flow exit ports 1122 may provide additional flow- paths for blood flow to exit at or near the distal end 1106 of the cannula in the first direction through the vessel. In the event the distal end 1106 is partially or completely occluded by the internal anatomy of the vessel, for example, the other cannula blood flow exit ports 1122 may inhibit interruption of the blood flow in the first direction within the vessel.

[0143] As illustrated in FIGS. 11A-11B, the cannula body 1102 may be or include a body of wire wound or braided tubing in which wound or braided wire is formed within or around tubing. The wire wound or braided tubing may have any suitable size, such as 15 Fr, 17 Fr, 19 Fr, or other desired size. In some embodiments, the entire cannula body 1102 may include wire wound or braided tubing. In some embodiments, the cannula body 1102 may include one or more wire wound or braided tubing sections and one or more tubing sections that are devoid of wire. For example, the portions of the cannula body 1102 in which the cannula blood flow exit ports 1112 and / or the other cannula blood flow exit ports 1122 are formed may be tubing devoid of wire. The absence of wire in the portions of the cannula body 1102 in w-hich the cannula blood flow exit ports 1112 and / or the other cannula blood flow exit ports 1122 are formed may simplify manufacturing of the cannula 1100. Alternatively or additionally, the cannula body 1102 may include a tapered tip at the distal end 1106 of a biocompatible metal or other material.

[0144] The balloon 1104 may include a flexible and biocompatible material such as silicone, polyurethane, Pebax, PET, ePTFE, or other suitable material. The balloon 1104 may be configured to expand, e.g., responsive to internal pressure from blood flow from the cannula blood flow exit ports 1112. The balloon 1104 may be configured to collapse against the cannula body 1102 when not subject to internal pressure and / or responsive to external pressure. For example, during insertion of the cannula 1100 into a vessel w hen there is no blood flow from the cannula body 1102 into the balloon 1104, the balloon 1104 may be configured to collapse against the cannula body 1102 as the balloon 1104 mounted to the cannula body 1102 passes through an incision at an insertion site into the vessel.Alternatively or additionally, and during removal of the cannula 1100 from the vessel when there is no blood flow from the cannula body 1102 into the balloon 1104, the balloon 1104 may be configured to collapse against the cannula body 1102 as the balloon 1104 mounted to the cannula body 1102 passes out through the incision at the insertion site.

[0145] FIGS. 11A-11B further depict the cannula hub 924 that includes the output port 926 coupled into the proximal end 1108 of the cannula 1100 and the two input ports 928, 930. As will be described in more detail, the two input ports 928, 930 may permit simultaneous coupling of the proximal end 1108 of the cannula 1100 to both a perfusion source through one of the input ports 928, 930 and to a valve assembly through the other of the input ports 930, 928. The valve assembly may permit introduction of intravascular catheters into the vessel through the cannula 1100.

[0146] FIG. 12 is a cross-sectional side view of the cannula 1100 inserted into a blood vessel 1200, arranged in accordance with at least one embodiment herein. As illustrated, the cannula 1100 has been inserted into the blood vessel 1200 through an incision 1202 having a width wi that is about equal to (or slightly larger than) a width of the cannula 1100 when the balloon 1104 is not inflated. After inflating the balloon 1104, e.g., by blood flow through the cannula 1100 and the balloon 1104, the cannula 1100 has a width w2 that is larger than the width wi of the incision. The inflated balloon 1104 thereby anchors the cannula 1100 to the blood vessel 1200 as any pull on the cannula 1100, unintentional or otherwise, to remove it from the blood vessel 1200 with the balloon 1104 inflated will cause the balloon 1104 and the portion of the cannula 1100 within the blood vessel 1200 to engage the blood vessel 1200 and resist removal.

[0147] FIG. 12 further includes various block arrows to indicate the general flow of blood through and out of the lumen 1110 of the cannula 1100 and the blood vessel 1200 in operation. Most of the blood may flow out the distal end 106 of the cannula 1100 and in a first direction through the blood vessel 1200 (e.g., retrograde if the blood vessel 1200 is the femoral artery). In addition, some of the blood may flow out of the cannula 1100 via the balloon 1104, e.g., via the cannula blood flow exit port 1112 and the balloon blood flow exit port 1104, in a second direction (opposite to the first direction) through the blood vessel 1200 e.g., antegrade if the blood vessel 1200 is the femoral artery).

[0148] As previously indicated, the cannula hub 924 of FIGS. 9A, 10A, and 11A may permit simultaneous coupling of the proximal end 908, 1008, 1108 of the cannula 900, 1000, 1100 or other cannulas herein to both a perfusion source through one of the input ports 928, 930 and to a valve assembly through the other of the input ports 930, 928.

[0149] FIGS. 13A-13B illustrate an example valve assembly 1300 that may be coupled to either of the input ports 928, 930, arranged in accordance w ith at least one embodiment described herein. In FIGS. 13A-13B, the cannula hub 924 is depicted w ith its output port 926 coupled into the proximal end 1108 of the cannula 1100, but the cannula hub 924 and valve assembly 1300 may more generally be implemented with any of the cannulas described herein.

[0150] In the example of FIG. 13A, the valve assembly 1300 is coupled to the input port 928 and the other input port 930 of the cannula hub 924 may be coupled to a pump arterial line of the perfusion source.

[0151] In the example of FIG. 13B, the valve assembly 1300 is coupled to the input port 930 and the other input port 928 of the cannula hub 924 may be coupled to the pump arterial line.

[0152] FIGS. 14A-14B depict another example bidirectional cannula 1400, arranged in accordance with at least one embodiment described herein. FIG. 14A depicts the entire cannula 1400 and FIG. 14B is a detail view- of a portion of the cannula 1400. As illustrated in FIGS. 14A-14B, the cannula 1400 includes a cannula body 1402 and a balloon 1404 coupled to the cannula body 1402. The cannula body 1402 and balloon 1404 are depicted as transparent in FIGS. 14A-14B such that a portion of the cannula body 1402 that passes through the balloon 1404 is visible within the balloon 1404. The cannula body 1402 and / or the balloon 1404 may be optically opaque or optically transparent in practice, or a combination of the two (e.y., some parts may be opaque while other parts may be transparent).

[0153] The cannula body 1402 is elongated and hollow7and has a distal end 1406 and a proximal end 1408 that are both open, the cannula body 1402 defining a lumen 1410 that extends from the distal end 1406 to the proximal end 1408. The cannula body 1402 also includes one or more cannula blood flow7exit ports 1412 formed in the cannula body 1402 at an intermediate location of the cannula body 1402 that is spaced apart from the proximal end 1408 and the distal end 1406. In this example, “spaced apart from the proximal end 1408 and the distal end 1406” may mean at least 40 mm, 50 mm, 60 mm, 70 mm, or more between the cannula blood flow7exit ports 1412 and each of the proximal end 1408 and the distal end 1406. More generally, the cannula blood flow exit ports 1412 may be formed in a portion of the cannula body 1402 that is encompassed by the balloon 1404. A single cannula blood flow exit port 1412 is visible in FIGS. 14A-14B encompassed by the balloon 1404 (at the intermediate location of the cannula body 1402). More generally, the cannula 1400 may include any number of cannula blood flow7exit ports 1412 encompassed by the balloon 1404 (or at the intermediate location), such as one, two, three, four, or more cannula blood flow7exit ports 1412. When there are multiple cannula blood flow exit ports 1412 encompassed by the balloon 1404 (or at the intermediate location), the cannula blood flow exit ports 1412 may be angularly spaced around the cannula body 1402 and / or may be longitudinally spaced along the cannula body 1402. For four cannula blood flow exit ports 1412, for instance, all four may be formed at the same longitudinal location along the cannula body 1402 but angularly spaced around the cannula body 1402, e.g., by 90 degrees. As another example involving four cannula blood flow exit ports 1412, two may be at one longitudinal location along the cannula body 1402 and angularly offset from each other by, e.g., 180 degrees, while two others may be at another longitudinal location and angularly offset from each other by, e.g., 180 degrees.

[0154] The balloon 1404 is coupled to the cannula body 1402 at the intermediate location spaced apart from the proximal end 1408 and the distal end 1406 w ith the cannula body 1402 passing through the balloon 1404 and is in fluid communication with the cannula blood flow exit ports 1412 and thereby with the lumen 1410 of the cannula 1400. Analogous to the cannula blood flow exit port 1412, the balloon 1404 being “spaced apart from the proximal end 1408 and the distal end 1406” may mean the balloon 1404 is at least 40 mm, 50 mm, 60 mm, 70 mm, or more from each of the proximal end 1408 and the distal end 1406. The balloon 1404 may be covered in bumps or other texture or may be smooth. Providing bumps or other texture on the balloon 1404 may increase friction between the balloon 1404 and, e.g., a vessel’s sidewalls, to inhibit movement between the cannula 1400 and the vessel.

[0155] In the illustrated example, the balloon 1404 is an eccentric balloon. In particular, while the balloon 1404 completely surrounds the cannula body 1402 at the intermediate location, it is eccentrically disposed relative to the cannula body 1402 with a greater volume of the balloon 1404, or an eccentric lobe, being disposed to one side of the cannula body 1402 than to any other side of the cannula body 1402. In comparison, some other balloons described herein, such as the balloons 404, 904, 1004, are generally disposed concentrically around the corresponding cannula body e.g., 402, 902, 1002) to which they are coupled. The eccentric disposition of the balloon 1404 relative to the cannula body 1402 may serve as a retention mechanism in a same or similar manner as the balloon 1104 of the cannula 1100 of FIGS. 11A-11B and as described w ith respect to FIG. 12. Alternatively or additionally, the balloon 1404 and / or other balloons described herein may be blow molded, dip molded, or formed in any other suitable manner.

[0156] The balloon 1404 may be coupled to the cannula body 1402 in any suitable manner. For example, the balloon 1404 may be thermally bonded to the cannula body 1402, solvent bonded to the cannula body 1402, or coupled to the cannula body 1402 in any othersuitable manner. In the illustrated example, the balloon 1404 may include a distal end 1414 and a proximal end 1416, each of which surrounds the cannula body 1402 and is bonded or otherwise coupled to the cannula body 1402.

[0157] The balloon 1404 includes a tubular portion 1418 that, in use, faces at least partially in an opposite direction from the distal end 1406. The tubular portion 148 defines a balloon blood flow exit port 1420. The balloon 1404 may be similar or analogous to the balloon 1104 of FIGS. 11A-11B apart from the inclusion of the tubular portion 1418 in FIGS. 14A-14B. The tubular portion 1419 may approximate a catheter lumen positioned to one side of the cannula body 1402 when inflated.

[0158] In operation, blood flows through the cannula 1400 by entering through the proximal end 1408, traveling completely or partially through the lumen 1410, and exiting through the distal end 1406 or the cannula blood flow7exit ports 1412. Blood flow exiting the distal end 1406 is configured to flow through the vessel in a first direction (e.g., retrograde if the vessel is the femoral artery). The cannula blood flow exit ports 1412 may be configured to direct blood flow into the balloon 1404. As such, blood flow exiting through the cannula blood flow exit ports 1412 is configured to flow into the balloon 1404. Blood flow may pass through and then exit the balloon 1404 through the tubular portion 1418 and specifically out through the balloon blood flow exit port 1420. The balloon blood flow exit port 1420 may be configured to direct blood flow in the opposite direction from the blood flow exiting the distal end 1406, e.g., by virtue of the balloon blood flow’ exit port 1420 being formed in the tubular portion 1418 of the balloon 1404 that faces the opposite direction from the distal end 1406 in use. As such, blood flow exiting the balloon blood flow exit port 1420, which faces at least partially proximally in use, is configured to flowthrough the vessel in a second direction (e.g., antegrade if the vessel is the femoral artery) opposite to the first direction. Although FIGS. 14A-14B depict a single tubular portion 1418 and balloon blood flow exit port 1420, in other embodiments the balloon 1404 may include multiple tubular portions 1418 and / or multiple balloon blood flow exit ports 1420 to provide multiple flow’ paths for blood flow to exit the balloon 1404 to inhibit interruption of the blood flow- in the second direction within the vessel.

[0159] In some embodiments, the cannula 1400 may further include one or more other cannula blood flow exit ports 1422 formed in the cannula body 1402 distal to the balloon 1404, e.g., at or near the distal end 1406. Although only one other cannula blood flow exit port 1422 is visible in FIG. 14A, the cannula 1400 may more generally include one, two, three, or even more other cannula blood flow exit ports 1422 formed in the cannula body 1402 distal to the balloon 1404 in any suitable arrangement (e.g., with equal and / or offset angular and / or longitudinal positions). The other cannula blood flow’ exit ports 1422 mayprovide additional flow paths for blood flow to exit at or near the distal end 1406 of the cannula in the first direction through the vessel. In the event the distal end 1406 is partially or completely occluded by the internal anatomy of the vessel, for example, the other cannula blood flow’ exit ports 1422 may inhibit interruption of the blood flow’ in the first direction within the vessel.

[0160] As illustrated in FIGS. 14A-14B, the cannula body 1402 may be or include a body of wire w ound or braided tubing in which wound or braided wire is formed within or around tubing. The wire wound or braided tubing may have any suitable size, such as 15 Fr, 17 Fr, 19 Fr, or other desired size. In some embodiments, the entire cannula body 1402 may include wire wound or braided tubing. In some embodiments, the cannula body 1402 may include one or more wire wound or braided tubing sections and one or more tubing sections that are devoid of wire. For example, the portions of the cannula body 1402 in which the cannula blood flow exit ports 1412 and / or the other cannula blood flow exit ports 1422 are formed may be tubing devoid of wire. The absence of wire in the portions of the cannula body 1402 in which the cannula blood flow exit ports 1412 and / or the other cannula blood flow exit ports 1422 are formed may simplify manufacturing of the cannula 1400. Alternatively or additionally, the cannula body 1402 may include a tapered tip at the distal end 1406 of a biocompatible metal or other material.

[0161] The balloon 1404 may include a flexible and biocompatible material such as silicone, polyurethane, Pebax, PET, ePTFE, or other suitable material. The balloon 1404 may be configured to expand, e.g., responsive to internal pressure from blood flow from the cannula blood flow’ exit ports 1412. The balloon 1404 may be configured to collapse against the cannula body 1402 w hen not subject to internal pressure and / or responsive to external pressure. For example, during insertion of the cannula 1400 into a vessel when there is no blood flow from the cannula body 1402 into the balloon 1404, the balloon 1404 may be configured to collapse against the cannula body 1402 as the balloon 1404 mounted to the cannula body 1402 passes through an incision at an insertion site into the vessel. Alternatively or additionally, and during removal of the cannula 1400 from the vessel when there is no blood flow from the cannula body 1402 into the balloon 1404, the balloon 1404 may be configured to collapse against the cannula body 1402 as the balloon 1404 mounted to the cannula body 1402 passes out through the incision at the insertion site.

[0162] FIGS. 14A-14B further depict the cannula hub 924 that includes the output port 926 coupled into the proximal end 1408 of the cannula 1400 and the two input ports 928, 930. As described elsewhere herein, the two input ports 928, 930 may permit simultaneous coupling of the proximal end 1408 of the cannula 1400 to both a perfusion source through one of the input ports 928, 930 and to a valve assembly through the other of the input ports930, 928. The valve assembly may permit introduction of intravascular catheters into the vessel through the cannula 1400.

[0163] FIGS. 15A-15B depict an example cannula hub 1550, arranged in accordance with at least one embodiment herein. The cannula hub 1550 may be included in or coupled to one or more of the cannulas and / or cannula assemblies described herein. For example, the cannula hub 1550 may be substituted for the cannula hub 924 in one or more of FIGS. 9A- 14B. As illustrated, the cannula hub 1550 includes an output port 1526 and an input port 1530. In some embodiments, the cannula hub 1550 may be coupled to a cannula body 1560 of a cannula 1500. For example, the output port 1526 may be coupled to a proximal end 1508 of the cannula body 1560. The cannula 1500 may include any of the cannulas or cannula assemblies herein, such as the cannulas 900, 1000, 1100, 1200, 1300, and / or 1400 of FIGS. 9A-14B.

[0164] In some embodiments, the cannula hub 1550 may include a flange 1532 or other anti-rotation feature between the output port 1526 and the input port 1530. The flange 1532 may include a flattened projection that extends lengthwise along at least a portion of the cannula hub 1550. In these and other embodiments, the flange 1532 may be configured to contact tissue of a patient at an insertion site of the cannula 1500, which may inhibit rotation of the cannula 1500 while the cannula 1500 is inserted in the patient. In particular, the cannula hub 1550 with the flange 1532 (or flattened projection) may be more resistant to rotation or rolling against the tissue of the patient than a cylindrical cannula hub. In some embodiments, the flange 1532 may be made of a semi-rigid material and / or an adhesive material as described above with respect to FIG. 9A.

[0165] In some embodiments, the flange 1532 may be integrally formed with the cannula hub 1550. In these and other embodiments, the flange 1532 may be integrally formed with the cannula hub 1550 by molding, machining, and / or otherwise fabricating the flange 1532 as a single, continuous structure with the cannula hub 1550. For example, the flange 1532 may be formed during an injection molding process in which the cannula hub 1550 and the flange 1532 are produced from the same material in a single manufacturing step, resulting in a unitary component with no seams and / or joints between the cannula hub 1550 and the flange 1532. In some embodiments, the flange 1532 may be shaped as a tab or any other geometry7extending radially outward from the central axis of the cannula hub 1550.

[0166] In some embodiments, the flange 1532 may include one or more flange holes(e.y., flange holes 1534a, 1534b, 1534c) (collectively, “flange holes 1534”) configured for the placement of sutures between the flange 1532 and the tissue of the patient through the flange holes 1534. Each of the flange holes 1534 may have a size and shape suitable for accommodating standard surgical suture needles and suture material. In someembodiments, the flange holes 1534 may be positioned at locations along the flange 1532 that may assist in fixing the cannula 1500 at an insertion site. In some embodiments, the number and / or spacing of the flange holes 1534 may be selected to distribute retention forces, which may reduce the likelihood of local tissue trauma during and / or after suture placement through the flange holes 1534.

[0167] In some embodiments, the cannula hub 1550 may include one or more valve assemblies 1527, 1537, such as coupled to one or more additional input ports 1528, 1529. In these and other embodiments, the valve assemblies 1527, 1537 may be configured for introducing a priming fluid into the cannula body 1560 and / or into a balloon via the additional input ports 1528, 1529. For example, the valve assemblies 1527, 1537 may be configured to receive a needle whereby the priming fluid may be injected into the additional input ports 1528, 1529. The valve assemblies 1527, 1537 may include silicone septum valves, luer-activated valves, and / or hemostasis valves, among other types of valves. Although not shown, a valve assembly may additionally or alternatively be coupled to the input port 1530. In some embodiments, the additional input ports 1528, 1529 may be in fluid communication with a lumen of a dilator 1562 positioned within the cannula. Additionally or alternatively, the dilator 1562 may have a priming fluid hole in fluid communication with the main lumen of the cannula 1500 and / or with the cannula blood flow exit port of the cannula 1500 wiien the dilator 1562 is positioned within the cannula 1500.

[0168] FIGS. 16A-16C depict various example primer delivery paths that may be implemented in a cannula or cannula assembly 1600A, 1600B, 1600C (hereinafter collectively “cannulas 1600” or generically “cannula 1600”), arranged in accordance with at least one embodiment herein. In some embodiments, the cannula 1600 may include a balloon 1672 coupled to the cannula body 1660 between the distal end and the proximal end of the cannula 1600, similar to one or more of the balloons depicted elsewhere herein, such as in FIGS. 9A-14B. Each of FIGS. 16A-16C includes a cross-sectional view of the corresponding cannula 1600 through the balloon 1672.

[0169] In these and other embodiments, the balloon 1672 may be in fluid communication with a cannula blood flow exit port 1670 of the cannula body 1660. In some embodiments, the balloon 1672 may include a proximal surface that defines one or more balloon blood flow exit ports (not illustrated in FIGS. 16A-16C), similar to other balloon proximal surfaces and balloon blood flow exit ports described herein.

[0170] FIGS. 16A-16C further illustrate a dilator 1662A, 1662B, or 1662C (hereinafter collectively “dilators 1662” or generically “dilator 1662”), positioned within the cannulas 1600. In these and other embodiments, a lumen 1664 (FIGS. 16A-16C), 1674 (FIG. 16C) ofthe dilator 1662 may be positioned w ithin the cannula 1600 when the dilator 1662 is positioned within the cannula 1600.

[0171] The primer delivery path of FIG. 16A includes a channel formed between an exterior of the dilator 1662 positioned within the cannula 1600A and an interior of the cannula 1600A along a lengthwise portion of the cannula 1600A and the dilator 1662. In some embodiments, the channel may extend from a proximal end of the cannula 1600A at least to, and in some embodiments may terminate at or near, the cannula blood flow- exit port 1670. As depicted in FIG. 16A, in some embodiments, the channel may be formed at least in part by a longitudinally extending depression or scoop 1666 along at least a portion of the exterior of the dilator 1662. Alternatively or additionally, the channel may be formed at least in part by a longitudinally extending depression or scoop along at least a portion of an interior of the cannula 1600A.

[0172] The primer delivery paths of FIGS. 16B and 16C include the lumen 1664 of the dilator 1662B or the lumen 1674 of the dilator 1662C. In some embodiments, the lumen 1664 may be a main lumen 1664 of the dilator 1662, e.g., for a guidewire. As depicted in FIG. 16C, in some embodiments, the lumen 1674 of the dilator 1662C may be a secondary lumen 1674 that is separate from the main lumen 1664.

[0173] In the example of FIG. 16B, the dilator 1662B has a priming fluid hole 1668A in fluid communication with the lumen 1664 and the cannula blood flow exit port 1670 of the cannula 1600B hen the dilator 1662B is positioned within the cannula 1600B. Accordingly, priming fluid may flow- through the lumen 1664, the priming fluid hole 1668A, the cannula blood flow exit port 1670, and into the balloon 1672.

[0174] In the example of FIG. 16C, the dilator 1662C has a priming fluid hole 1668B in fluid communication wdth the lumen 1674 and the cannula blood flow exit port 1670 of the cannula 1600C w hen the dilator 1662C is positioned wdthin the cannula 1600C. Accordingly, priming fluid may flow through the lumen 1674, the priming fluid hole 1668B, the cannula blood flow exit port 1670, and into the balloon 1672.Sterilization

[0175] Any of the systems, devices, apparatuses, etc. herein may be sterilized (for example, wdth heat / thermal, pressure, steam, radiation, and / or chemicals, etc.) to ensure they are safe for use wdth patients, and any of the methods herein may include sterilization of the associated system, device, apparatus, etc. as one of the steps of the method. Examples of heat / thermal sterilization include steam sterilization and autoclaving. Examples of radiation for use in sterilization include, w ithout limitation, gamma radiation, ultra-violet radiation, and electron beam. Examples of chemicals for use in sterilization include, without limitation,ethylene oxide, hydrogen peroxide, peracetic acid, formaldehyde, and glutaraldehyde. Sterilization w ith hydrogen peroxide may be accomplished using hydrogen peroxide plasma, for example.Additional Examples of the Disclosed Technology

[0176] In view of the above-described implementations of the disclosed subject matter, this application discloses the additional examples enumerated below. It should be noted that one feature of an example in isolation or more than one feature of the example taken in combination and, optionally, in combination with one or more features of one or more further examples are further examples also falling within the disclosure of this application.

[0177] Example 1. A cannula, comprising:

[0178] a cannula body that is elongated and hollow, the cannula body having a distal end and a proximal end that are both open and a cannula blood flow exit port formed in an intermediate segment of the cannula body between the distal end and the proximal end and facing an opposite direction from the open distal end; and

[0179] a retainer coupled to the cannula body and movable between a stowed configuration for insertion into a vessel of a patient and a deployed configuration.

[0180] Example 2. The cannula of any example herein, particularly of example 1, wherein the retainer in the deployed configuration is configured to retain the cannula inserted in the vessel.

[0181] Example 3. The cannula of any example herein, particularly of example 1 or 2, wherein the retainer in the deployed configuration is configured to inhibit removal of the cannula from the vessel.

[0182] Example 4. The cannula of any example herein, particularly of any one of examples 1-3, wherein the retainer in the stowed configuration is positioned tight against the cannula body during insertion of the cannula into the vessel.

[0183] Example 5. The cannula of any example herein, particularly of any one of examples 1-4, wherein the retainer comprises a Nitinol structure.

[0184] Example 6. The cannula of any example herein, particularly of any one of examples 1-5, wherein the intermediate segment of the cannula body in which the cannula blood flow exit port is formed comprises an ankle of the cannula body.

[0185] Example 7. The cannula of any example herein, particularly of any one of examples 1-6, wherein the cannula body comprises a first segment that includes the distal end, a second segment parallel to the first segment and that includes the proximal end, andthe intermediate segment that connects the first segment and the second segment, the intermediate segment being angled relative to the first segment and the second segment.

[0186] Example 8. The cannula of any example herein, particularly of any one of examples 1-7, wherein the retainer comprises a tube coupled to an exterior of the cannula body and an expandable structure retained within the tube in the stowed configuration and deployed outside the tube in the deployed configuration.

[0187] Example 9. The cannula of any example herein, particularly of example 8, wherein the expandable structure is deployed from within the tube manually by a user or automatically in response to removal of a dilator from the cannula.

[0188] Example to. The cannula of any example herein, particularly of example 8, wherein the expandable structure comprises a wire and in the deployed configuration, the wire forms a framed protrusion that extends away from the intermediate segment near the cannula blood flow exit port and inhibits occlusion of the cannula blood flow exit port.

[0189] Example 11. The cannula of any example herein, particularly of any one of examples 1-10, further comprising a cannula hub coupled to the cannula body, the cannula hub comprising an output port coupled to the proximal end of the cannula body and an input port.

[0190] Example 12. The cannula of any example herein, particularly of example 11, wherein the cannula hub further comprises a flange between the output port and the input port, the flange configured to contact tissue of a patient at an insertion site of the cannula to inhibit rotation of the cannula while the cannula is inserted in the patient.

[0191] Example 13. The cannula of any example herein, particularly of example 12, wherein the flange comprises one or more of a semi-rigid material and an adhesive material.

[0192] Example 14. The cannula of any example herein, particularly of example 12 or 13, wherein the flange is integrally formed w ith the cannula hub.

[0193] Example 15. The cannula of any example herein, particularly of any one of examples 12-14, wherein the flange includes one or more flange holes configured for placement of sutures between the flange and the tissue of the patient through the one or more flange holes.

[0194] Example 16. The cannula of any example herein, particularly of any one of examples 1-15, wherein a size of an opening at the distal end of the cannula is larger than a size of the cannula blood flow exit port.

[0195] Example 17. A cannula, comprising:

[0196] a cannula body that is elongated and hollow, the cannula body having a distal end and a proximal end that are both open and one or more cannula blood flow exit ports between the distal end and the proximal end; and

[0197] a balloon coupled to the cannula body between the distal end and the proximal end in fluid communication with the one or more cannula blood flow exit ports of the cannula body, the balloon including a proximal surface that defines one or more balloon blood flow exit ports.

[0198] Example 18. The cannula of any example herein, particularly of example 17, wherein the balloon is thermally bonded to the cannula body.

[0199] Example 19. The cannula of any example herein, particularly of example 17, wherein the balloon is solvent bonded to the cannula body.

[0200] Example 20. The cannula of any example herein, particularly of any one of examples 17-19, wherein the one or more cannula blood flow exit ports are configured to direct blood flow into the balloon.

[0201] Example 21. The cannula of any example herein, particularly of any one of examples 17-20, wherein the one or more balloon blood flow exit ports are configured to direct blood flow in an opposite direction from blood flow that exits the distal end of the cannula body.

[0202] Example 22. The cannula of any example herein, particularly of any one of examples 17-21, wherein the one or more cannula blood flow exit ports comprise four cannula blood flow exit ports.

[0203] Example 23. The cannula of any example herein, particularly of any one of examples 17-22, wherein the one or more balloon blood flow exit ports comprise three balloon blood flow exit ports.

[0204] Example 24. The cannula of any example herein, particularly of example 23, wherein each of the three balloon blood flow exit ports is equally angularly offset around the balloon from the other balloon blood flow exit ports.

[0205] Example 25. The cannula of any example herein, particularly of any one of examples 17-24, wherein each of the one or more balloon blood flow exit ports is formed in the proximal surface of the balloon that faces an opposite direction from the distal end of the cannula body.

[0206] Example 26. The cannula of any example herein, particularly of any one of examples 17-25, wherein an exterior of the balloon is textured.

[0207] Example 27. The cannula of any example herein, particularly of any one of examples 17-26, wherein the balloon is collapsible in response to insertion of the cannula through a cannula insertion site and expandable in response to blood flow within the cannula.

[0208] Example 28. The cannula of any example herein, particularly of any one of examples 17-27, wherein the distal end of the cannula body includes two or more openings.

[0209] Example 29. The cannula of any example herein, particularly of any one of examples 17-28, wherein the balloon is in fluid communication with a blood flow lumen of the cannula through the one or more cannula blood flow exit ports.

[0210] Example 30. The cannula of any example herein, particularly of any one of examples 17-29, wherein the one or more cannula blood flow exit ports are formed in the cannula body adjacent to the distal end and the balloon is coupled to the cannula body adjacent to the distal end.

[0211] Example 31. The cannula of any example herein, particularly of any one of examples 17-29, w herein the one or more cannula blood flow exit ports are formed in the cannula body at an intermediate location of the cannula body spaced apart from the proximal end and the distal end of the cannula body and the balloon is coupled to the cannula at the intermediate location.

[0212] Example 32. The cannula of any example herein, particularly of any one of examples 17-31, wherein the balloon is ellipsoidal when inflated.

[0213] Example 33. The cannula of any example herein, particularly of any one of examples 17-31, wherein the balloon is frustoconical when inflated.

[0214] Example 34. The cannula of any example herein, particularly of any one of examples 17-31, w herein the balloon comprises an eccentric lobe positioned to one side of the cannula body when inflated.

[0215] Example 35. The cannula of any example herein, particularly of example 34, wherein the eccentric lobe includes a tubular portion that extends in an opposite direction from a distal end of the cannula body in use, the tubular portion extending from the proximal surface of the balloon and defining the one or more balloon blood flow exit ports.

[0216] Example 36. The cannula of any example herein, particularly of any one of examples 17-35, further comprising a cannula hub coupled to the cannula body, the cannula hub comprising an output port coupled to the proximal end of the cannula body and an input port.

[0217] Example 37. The cannula of any example herein, particularly of example 36, wherein the cannula hub further comprises a flange between the output port and the input port, the flange configured to contact tissue of a patient at an insertion site of the cannula to inhibit rotation of the cannula while the cannula is inserted in the patient.

[0218] Example 38. The cannula of any example herein, particularly of example 37, wherein the flange comprises one or more of a semi-rigid material and an adhesive material.

[0219] Example 39. The cannula of any example herein, particularly of example 37 or 38, wherein the flange is integrally formed with the cannula hub.

[0220] Example 40. The cannula of any example herein, particularly of any one of examples 37-39, wherein the flange includes one or more flange holes configured for placement of sutures between the flange and the tissue of the patient through the one or more flange holes.

[0221] Example 41. The cannula of any example herein, particularly of any one of examples 36-40, wherein the cannula hub further comprises one or more valve assemblies configured for introducing a priming fluid into one or more of the cannula body and the balloon.

[0222] Example 42. The cannula of any example herein, particularly of example 41, further comprising a channel formed between an exterior of a dilator positioned within the cannula and an interior of the cannula, the channel terminating at one end of the cannula blood flow exit port and in fluid communication with the one or more valve assemblies.

[0223] Example 43. The cannula of any example herein, particularly of example 42, wherein the channel is formed in part by a longitudinally extending depression or scoop along at least a portion of the exterior of the dilator.

[0224] Example 44. The cannula of any example herein, particularly of example 41, wherein the one or more valve assemblies are in fluid communication w ith a lumen of a dilator positioned within the cannula, the dilator having a priming fluid hole in fluid communication w ith the lumen and the cannula blood flow exit port of the cannula when the dilator is positioned within the cannula.

[0225] Example 45. The cannula of any example herein, particularly of example 44, wherein the lumen of the dilator comprises a main lumen for a guidewire.

[0226] Example 46. The cannula of any example herein, particularly of example 44, wherein the lumen of the dilator comprises a secondary lumen that is separate from a main lumen of the dilator for a guidewire.

[0227] Example 47. The cannula of any example herein, particularly of any one of examples 41-46, wherein the priming fluid is one or more of:

[0228] saline;

[0229] heparinized saline;

[0230] sterile water;

[0231] blood;

[0232] a dextrose solution; and

[0233] an electrolyte solution.

[0234] Example 48. The cannula of any example herein, particularly of any one of examples 17-47, wherein the one or more cannula blood flow exit ports are at least as large as the one or more balloon blood flow exit ports.

[0235] Example 49. The cannula of any example herein, particularly of any one of examples 17-48, wherein a size of an opening at the distal end of the cannula is larger than an aggregate size of the one or more cannula blood flow exit ports.

[0236] Example 50. A cannula assembly comprising:

[0237] a first cannula comprising a cannula body having a distal end and a proximal end, the cannula body defining a first lumen that extends from the distal end to the proximal end and a second lumen that extends at least partially between the distal end and the proximal end, wherein in a plane perpendicular to a length of the first cannula, the first lumen has a larger cross-sectional area than the second lumen; and

[0238] a second cannula receivable within the second lumen of the first cannula, the second lumen having a turn at its distal end that forces the second cannula to change direction at the turn where the second cannula exits the second lumen of the first cannula.

[0239] Example 51. The cannula assembly of any example herein, particularly of example 50, wherein the second cannula has a diameter in a range from 5-10 French (F).

[0240] Example 52. The cannula assembly of any example herein, particularly of example 51, wherein the second cannula has a diameter of 6 F.

[0241] Example 53. The cannula assembly of any example herein, particularly of any one of examples 50-52, wherein the first cannula and the second cannula assembled together as the cannula assembly are insertable into a vessel of a patient through a common incision in the vessel.

[0242] Example 54. The cannula assembly of any example herein, particularly of example 53, wherein:

[0243] the first cannula and the second cannula assembled together as the cannula assembly and inserted into the vessel include the distal end of the first cannula that extends from the common incision in a first direction within the vessel and a distal end of the second cannula that extends from the common incision in an opposite second direction within the vessel; and

[0244] the distal end of the first cannula extending in the first direction within the vessel and the distal end of the second cannula extending in the opposite second direction within the vessel are collectively configured to inhibit removal of the cannula assembly from the vessel.

[0245] Example 55. The cannula assembly of any example herein, particularly of any one of examples 50-54, wherein a lumen of the second cannula and the first lumen of the first cannula are configured to be in fluid communication with a common perfusion source.

[0246] Example 56. The cannula assembly of any example herein, particularly of any one of examples 50-55, wherein the second cannula includes one or more holes formed in a sidewall of the second cannula near a distal end of the second cannula.

[0247] Example 57. The cannula assembly of any example herein, particularly of any one of examples 50-56, further comprising a cannula hub coupled to the first cannula, the cannula hub comprising an output port coupled to the proximal end of the first cannula and an input port.

[0248] Example 58. The cannula assembly of any example herein, particularly of example 57, wherein the cannula hub further comprises a flange between the output port and the input port, the flange configured to contact tissue of a patient at an insertion site of the cannula assembly to inhibit rotation of the cannula assembly while the cannula assembly is inserted in the patient.

[0249] Example 59. The cannula assembly of any example herein, particularly of example 58, wherein the flange comprises one or more of a semi-rigid material and an adhesive material.

[0250] Example 60. The cannula assembly of any example herein, particularly of example 58 or 59, wherein the flange is integrally formed w ith the cannula hub.

[0251] Example 61. The cannula assembly of any example herein, particularly of any one of examples 58-60, wherein the flange includes one or more flange holes configured forplacement of sutures between the flange and the tissue of the patient through the one or more flange holes.

[0252] Example 62. The cannula assembly of any one of examples 50-61, wherein a size of an opening at the distal end of the cannula assembly is larger than an aggregate size of one or more cannula blood flow exit ports.

[0253] Example 63. A method to insert a cannula into a blood vessel of a patient, the cannula comprising a cannula body having an open distal end, an intermediate segment proximal to the distal end in which a cannula blood flow exit port is formed, and a retainer coupled to the cannula body and movable between a stowed configuration and a deployed configuration, the method comprising:

[0254] accessing the blood vessel of the patient with a needle;[o255] advancing a guidewire through the needle into the blood vessel;

[0256] removing the needle while retaining the guidewire in the blood vessel;

[0257] advancing a dilator and the cannula along the guidewire into the blood vessel until:

[0258] the distal end of the cannula is positioned to direct blood flow- from the cannula in a first direction in the blood vessel;

[0259] the cannula blood flow exit port is arranged to direct blood flow from the cannula in a second direction in the blood vessel that is opposite the first direction; and

[0260] a retainer in a stowed configuration coupled to the cannula body is at least partially positioned within the blood vessel;

[0261] removing the dilator; and

[0262] altering the retainer to a deployed configuration in which a portion of the retainer is deployed within the blood vessel.

[0263] Example 64. The method of any example herein, particularly of example 63, wherein altering the retainer to the deployed configuration occurs automatically in response to removal of the dilator from the cannula.

[0264] Example 65. The method of any example herein, particularly of example 63 or 64, w-herein:

[0265] the retainer comprises a tube coupled to an exterior of the cannula body and an expandable structure retained within the tube in the stowed configuration such that altering the retainer to the deployed configuration comprises manually forcing the expandable structure out of the tube to the deployed configuration in the blood vessel.

[0266] Example 66. The method of any example herein, particularly of example 65, wherein the expandable structure comprises a w ire and in response to the expandable structure being forced out of the tube, the method further comprises the wire forming a framed protrusion that extends away from the intermediate segment near the cannula blood flow exit port and inhibits occlusion of the cannula blood flow exit port by a sidew all of the blood vessel.

[0267] Example 67. The method of any example herein, particularly of any one of examples 63-65, further comprising:

[0268] coupling a proximal end of the cannula to a blood flow source; and

[0269] flow ing blood through the cannula from the blood flow’ source and into the blood vessel in both the first direction and the second direction, including:

[0270] flowing blood out of the distal end of the cannula in the first direction in the blood vessel; and

[0271] flowing blood out of the cannula blood flow exit port in the second direction in the blood vessel that is opposite the first direction.

[0272] Example 68. The method of any example herein, particularly of example 67, wherein:

[0273] coupling the proximal end of the cannula to the blood flow source includes coupling the proximal end of the cannula to an output port of a cannula hub and coupling a first input port of the cannula hub to the blood flow’ source; and

[0274] the method further comprises introducing an intravascular catheter into the blood vessel through a second input port of the cannula hub, the output port, and the cannula while maintaining blood flow into the blood vessel through the first input port, the output port, and the cannula.

[0275] Example 69. The method of any example herein, particularly of example 68, wherein the cannula hub further comprises a flange between the output port and the first and second input ports, the method further comprising positioning the flange against tissue of a patient at an insertion site of the cannula to inhibit rotation of the cannula w hile the cannula is inserted in the patient.

[0276] Example 70. The method of any example herein, particularly of example 69, wherein the flange includes one or more flange holes, the method further comprising placing sutures between the flange and the tissue of the patient through the one or more flange holes.

[0277] Example 71. The method of any example herein, particularly of any one of examples 63-70, wherein a size of an opening at the distal end of the cannula is larger than an aggregate size of one or more cannula blood flow exit ports, the method further comprising flowing more blood flow through the distal end of the cannula than through the one or more cannula blood flow exit ports.

[0278] Example 72. A method to insert a cannula into a blood vessel of a patient, the cannula comprising a cannula body having an open distal end and a balloon coupled to the cannula body proximal to the distal end, the balloon including a proximal surface that defines one or more balloon blood flow exit ports, the method comprising:

[0279] accessing the blood vessel of the patient with a needle;

[0280] advancing a gui ewire through the needle into the blood vessel;

[0281] removing the needle while retaining the guidewire in the blood vessel;

[0282] advancing a dilator and the cannula along the guidewire into the blood vessel until:

[0283] the distal end of the cannula is positioned to direct blood flow from the cannula in a first direction in the blood vessel; and

[0284] the balloon is positioned in the blood vessel w ith the one or more balloon blood flow exit ports defined in the proximal surface of the balloon positioned to direct blood flow from the cannula in a second direction in the blood vessel that is opposite the first direction; and

[0285] removing the dilator.

[0286] Example 73. The method of any example herein, particularly of example 72, further comprising:

[0287] coupling a proximal end of the cannula to a blood flow source; and

[0288] flowing blood through the cannula from the blood flow source and into the blood vessel, including:

[0289] flowing blood out of the distal end of the cannula in the first direction in the blood vessel; and

[0290] flowing blood out of one or more cannula blood flow exit ports defined in the cannula into the balloon; and

[0291] flowing blood through the balloon from the cannula and into the blood vessel, including flowing blood out of the one or more balloon blood flow exit ports of the balloon in the second direction in the blood vessel that is opposite the first direction.

[0292] Example 74. The method of any example herein, particularly of example 73, wherein:

[0293] coupling the proximal end of the cannula to the blood flow source includes coupling the proximal end of the cannula to an output port of a cannula hub and coupling a first input port of the cannula hub to the blood flow source; and

[0294] the method further comprises introducing an intravascular catheter into the blood vessel through a second input port of the cannula hub, the output port, and the cannula while maintaining blood flow into the blood vessel through the first input port, the output port, and the cannula.

[0295] Example 75. The method of any example herein, particularly of any one of examples 72-74, further comprising collapsing the balloon against the cannula body as the balloon coupled to the cannula is inserted through an incision into the blood vessel while advancing the dilator and the cannula along the guidewire and into the blood vessel.

[0296] Example 76. The method of any example herein, particularly of any one of examples 72-75, wherein after the balloon is positioned in the blood vessel, the method further comprises filling and expanding the balloon within the blood vessel with blood from a blood flow source.

[0297] Example 77. The method of any example herein, particularly of any one of examples 72-76, further comprising introducing priming fluid into the balloon prior to removing the dilator.

[0298] Example 78. The method of any example herein, particularly of example 77, wherein the dilator is configured with a groove extending longitudinally along at least a portion of an exterior of the dilator to create a priming fluid channel between the outside of the dilator and the inside of the cannula body, the priming fluid channel in fluid communication with a cannula blood flow exit port defined in the cannula, w herein introducing priming fluid into the balloon comprises introducing priming fluid into the balloon through the priming fluid channel and the cannula blood flow exit port.

[0299] Example 79. The method of any example herein, particularly of example 77, wherein the dilator includes a priming fluid hole extending radially therethrough that is configured to be aligned with a cannula blood flow exit port defined in the cannula into the balloon, w herein introducing priming fluid into the balloon comprises introducing priming fluid into the balloon through a main lumen of the dilator, the priming fluid hole, and the cannula blood flow exit port.

[0300] Example 80. The method of any example herein, particularly of any one of examples 72-76, wherein the dilator includes a priming fluid lumen extending longitudinallythrough at least a portion of the dilator and in fluid communication w ith a priming fluid hole formed in the dilator that is configured to be aligned with a cannula blood flow exit port defined in the cannula into the balloon, wherein introducing priming fluid into the balloon comprises introducing priming fluid into the balloon through the priming fluid lumen of the dilator, the priming fluid hole, and the cannula blood flow exit port.

[0301] Example 81. The method of any example herein, particularly of any one of examples 74-80, wherein the cannula hub further comprises a flange between the output port and the first and second input ports, the method further comprising positioning the flange against tissue of a patient at an insertion site of the cannula to inhibit rotation of the cannula while the cannula is inserted in the patient.

[0302] Example 82. The method of any example herein, particularly of example 81, wherein the flange includes one or more flange holes, the method further comprising placing sutures between the flange and the tissue of the patient through the one or more flange holes.

[0303] Example 83. The method of any example herein, particularly of any one of examples 72-82, wherein one or more cannula blood flow' exit ports in the cannula are at least as large as the one or more balloon blood flow exit ports.

[0304] Example 84. The method of any example herein, particularly of any one of examples 72-83, wherein a size of an opening at the distal end of the cannula is larger than an aggregate size of one or more cannula blood flow exit ports in the cannula.

[0305] Example 85. A method to insert a cannula assembly into a blood vessel of a patient, the cannula assembly comprising a first cannula having a cannula body with a distal end and a proximal end, the cannula body defining a first lumen that extends from the distal end to the proximal end and a second lumen that extends at least partially between the distal end and the proximal end, the method comprising:

[0306] accessing a blood vessel of a patient with a needle;

[0307] advancing a guidewdre through the needle into the blood vessel;

[0308] removing the needle while retaining the guidewire in the blood vessel;

[0309] advancing a dilator and the first cannula along the guidewire into the blood vessel until:

[0310] the distal end of the cannula body of the first cannula is positioned to direct blood flow from the first cannula in a first direction in the blood vessel; and

[0311] a distal end of the second lumen is positioned within the blood vessel w hile a proximal end of the second lumen remains outside the blood vessel;

[0312] advancing a second cannula through the second lumen of the first cannula until distal and proximal ends of the second cannula extend from the distal and proximal ends of the second lumen, the distal end of the second lumen having a turn that forces the second cannula to change direction at the turn where the second cannula exits the second lumen, the distal end of the second cannula positioned to direct blood flow from the second cannula in a second direction in the blood vessel that is opposite the first direction; and

[0313] removing the dilator.

[0314] Example 86. The method of any example herein, particularly of example 85, further comprising:

[0315] coupling the proximal end of the first cannula to a blood flow source;

[0316] coupling the proximal end of the second cannula to the blood flow source;

[0317] flowing blood through the first cannula from the blood flow source and into the blood vessel, including flowing blood out of the distal end of the first cannula in the first direction in the blood vessel; and

[0318] flow ing blood through the second cannula from the blood flow source and into the blood vessel, including flowing blood out of the distal end of the second cannula in the second direction in the blood vessel that is opposite the first direction.

[0319] Example 87. The method of any example herein, particularly of example 86, wherein:

[0320] coupling the proximal end of the first cannula to the blood flow source includes coupling the proximal end of the first cannula to an output port of a cannula hub and coupling a first input port of the cannula hub to the blood flow source; and

[0321] the method further comprises introducing an intravascular catheter into the blood vessel through a second input port of the cannula hub, the output port, and the first cannula while maintaining blood flow into the blood vessel through the first input port, the output port, and the cannula assembly.

[0322] Example 88. The method of any example herein, particularly of example 87, wherein the cannula hub further comprises a flange between the output port and the first and second input ports, the method further comprising positioning the flange against tissue of a patient at an insertion site of the cannula assembly to inhibit rotation of the cannula assembly while the cannula assembly is inserted in the patient.

[0323] Example 89. The method of any example herein, particularly of example 88, wherein the flange includes one or more flange holes, the method further comprising placingsutures between the flange and the tissue of the patient through the one or more flange holes.

[0324] Example 90. The method of any example herein, particularly of any one of examples 85-89, wherein:

[0325] the second cannula includes one or more cannula blood flow exit ports formed in a sidewall of the second cannula closer to the distal end of the second cannula than the proximal end of the second cannula; and

[0326] advancing the second cannula through the second lumen of the first cannula includes advancing the second cannula through the second lumen of the first cannula until the one or more cannula blood flow exit ports formed in the sidew all of the second cannula are positioned distal to the distal end of the second lumen of the first cannula.

[0327] Example 91. The method of any example herein, particularly of any one of examples 85-90, wherein a size of an opening at the distal end of the cannula assembly is larger than an aggregate size of the one or more cannula blood flow exit ports formed in the sidewall of the second cannula.

[0328] The features described herein with regard to any example may be combined with other features described in any one or more of the other examples, unless otherwise stated. For example, any one or more of the features of one docking device may be combined with any one or more features of another docking device.

[0329] In view of the many possible examples to which the principles of the disclosed technology may be applied, it should be recognized that the illustrated examples are only preferred examples of the technology and should not be taken as limiting the scope of the disclosure. Rather, the scope of the claimed subject matter is defined by the following claims and their equivalents.

Claims

WHAT IS CLAIMED IS:

1. A cannula, comprising: a cannula body that is elongated and hollow, the cannula body having a distal end and a proximal end that are both open and a cannula blood flow exit port formed in an intermediate segment of the cannula body between the distal end and the proximal end and facing an opposite direction from the open distal end; and a retainer coupled to the cannula body and movable between a stowed configuration for insertion into a vessel of a patient and a deployed configuration.

2. The cannula of claim 1, wherein the retainer in the deployed configuration is configured to retain the cannula inserted in the vessel.

3. The cannula of claim 1 or 2, wherein the retainer in the deployed configuration is configured to inhibit removal of the cannula from the vessel.

4. The cannula of any one of claims 1-3, wherein the retainer in the stowed configuration is positioned tight against the cannula body during insertion of the cannula into the vessel.

5. The cannula of any one of claims 1-4, wherein the retainer comprises a Nitinol structure.

6. The cannula of any one of claims 1-5, wherein the intermediate segment of the cannula body in which the cannula blood flow exit port is formed comprises an ankle of the cannula body.

7. The cannula of any one of claims 1-6, wherein the cannula body comprises a first segment that includes the distal end, a second segment parallel to the first segment and that includes the proximal end, and the intermediate segment that connects the first segment and the second segment, the intermediate segment being angled relative to the first segment and the second segment.

8. The cannula of any one of claims 1-7, wherein the retainer comprises a tube coupled to an exterior of the cannula body and an expandable structure retained with in the tube in the stowed configuration and deployed outside the tube in the deployed configuration.

9. The cannula of claim 8, wherein the expandable structure is deployed from with i n the tube manually by a user or automatically in response to removal of a dilator from the cannula.

10. The cannula of claim 8, wherein the expandable structure comprises a w ire and in the deployed configuration, the w ire forms a framed protrusion that extends away from the intermediate segment near the cannula blood flow exit port and inhibits occlusion of the cannula blood flow exit port. n. The cannula of any one of claims 1-10, further comprising a cannula hub coupled to the cannula body, the cannula hub comprising an output port coupled to the proximal end of the cannula body and an input port.

12. The cannula of claim 11, wherein the cannula hub further comprises a flange between the output port and the input port, the flange configured to contact tissue of a patient at an insertion site of the cannula to inhibit rotation of the cannula while the cannula is inserted in the patient.

13. The cannula of claim 12, wherein the flange comprises one or more of a semirigid material and an adhesive material.

14. The cannula of claim 12 or 13, wherein the flange is integrally formed w ith the cannula hub.

15. The cannula of any one of claims 12-14, wherein the flange includes one or more flange holes configured for placement of sutures between the flange and the tissue of the patient through the one or more flange holes.

16. The cannula of any one of claims 1-15, wherein a size of an opening at the distal end of the cannula is larger than a size of the cannula blood flow exit port.

17. A cannula, comprising: a cannula body that is elongated and hollow’, the cannula body having a distal end and a proximal end that are both open and one or more cannula blood flowexit ports between the distal end and the proximal end; and a balloon coupled to the cannula body between the distal end and the proximal end in fluid communication with the one or more cannula blood flow exit ports of the cannula body, the balloon including a proximal surface that defines one or more balloon blood flow exit ports.

18. The cannula of claim 17, wherein the balloon is thermally bonded to the cannula body.

19. The cannula of claim 17, wherein the balloon is solvent bonded to the cannula body.

20. The cannula of any one of claims 17-19, w herein the one or more cannula blood flow exit ports are configured to direct blood flow’ into the balloon.

21. The cannula of any one of claims 17-20, wherein the one or more balloon blood flow exit ports are configured to direct blood flow in an opposite direction from blood flow that exits the distal end of the cannula body.

22. The cannula of any one of claims 17-21, wherein the one or more cannula blood flow exit ports comprise four cannula blood flow exit ports.

23. The cannula of any one of claims 17-22, wherein the one or more balloon blood flow exit ports comprise three balloon blood flow exit ports.

24. The cannula of claim 23, wherein each of the three balloon blood flow exit ports is equally angularly offset around the balloon from the other balloon blood flow exit ports.

25. The cannula of any one of claims 17-24, wherein each of the one or more balloon blood flow exit ports is formed in the proximal surface of the balloon that faces an opposite direction from the distal end of the cannula body.

26. The cannula of any one of claims 17-25, wherein an exterior of the balloon is textured.

27. The cannula of any one of claims 17-26, wherein the balloon is collapsible in response to insertion of the cannula through a cannula insertion site and expandable in response to blood flow within the cannula.

28. The cannula of any one of claims 17-27, wherein the distal end of the cannula body includes two or more openings.

29. The cannula of any one of claims 17-28, wherein the balloon is in fluid communication with a blood flow lumen of the cannula through the one or more cannula blood flow exit ports.

30. The cannula of any one of claims 17-29, wherein the one or more cannula blood flow exit ports are formed in the cannula body adjacent to the distal end and the balloon is coupled to the cannula body adjacent to the distal end.

31. The cannula of any one of claims 17-29, wherein the one or more cannula blood flow exit ports are formed in the cannula body at an intermediate location of the cannula body spaced apart from the proximal end and the distal end of the cannula body and the balloon is coupled to the cannula at the intermediate location.

32. The cannula of any one of claims 17-31, wherein the balloon is ellipsoidal w hen inflated.33- The cannula of any one of claims 17-31, wherein the balloon is frustoconical when inflated.

34. The cannula of any one of claims 17-31, wherein the balloon comprises an eccentric lobe positioned to one side of the cannula body when inflated.

35. The cannula of claim 34, wherein the eccentric lobe includes a tubular portion that extends in an opposite direction from a distal end of the cannula body in use, the tubular portion extending from the proximal surface of the balloon and defining the one or more balloon blood flow exit ports.

36. The cannula of any one of claims 17-35, further comprising a cannula hub coupled to the cannula body, the cannula hub comprising an output port coupled to the proximal end of the cannula body and an input port.

37. The cannula of claim 36, wherein the cannula hub further comprises a flange between the output port and the input port, the flange configured to contact tissue of a patient at an insertion site of the cannula to inhibit rotation of the cannula while the cannula is inserted in the patient.

38. The cannula of claim 37, wherein the flange comprises one or more of a semirigid material and an adhesive material.

39. The cannula of claim 37 or 38, wherein the flange is integrally formed with the cannula hub.

40. The cannula of any one of claims 37-39, wherein the flange includes one or more flange holes configured for placement of sutures between the flange and the tissue of the patient through the one or more flange holes.

41. The cannula of any one of claims 36-40, wherein the cannula hub further comprises one or more valve assemblies configured for introducing a priming fluid into one or more of the cannula body and the balloon.

42. The cannula of claim 41, further comprising a channel formed between an exterior of a dilator positioned within the cannula and an interior of the cannula, the channel terminating at one end of the cannula blood flow exit port and in fluid communication w ith the one or more valve assemblies.

43. The cannula of claim 42, w herein the channel is formed in part by a longitudinally extending depression or scoop along at least a portion of the exterior of the dilator.

44. The cannula of claim 41, wherein the one or more valve assemblies are in fluid communication with a lumen of a dilator positioned within the cannula, the dilator having apriming fluid hole in fluid communication w ith the lumen and the cannula blood flow exit port of the cannula when the dilator is positioned within the cannula.

45. The cannula of claim 44, wherein the lumen of the dilator comprises a main lumen for a guidewire.

46. The cannula of claim 44, wherein the lumen of the dilator comprises a secondary lumen that is separate from a main lumen of the dilator for a guidewire.

47. The cannula of any one of claims 41-46, wherein the priming fluid is one or more of: saline; heparinized saline; sterile water; blood; a dextrose solution; and an electrolyte solution.

48. The cannula of any one of claims 17-47, wherein the one or more cannula blood flow exit ports are at least as large as the one or more balloon blood flow exit ports.

49. The cannula of any one of claims 17-48, wherein a size of an opening at the distal end of the cannula is larger than an aggregate size of the one or more cannula blood flow exit ports.

50. A cannula assembly comprising: a first cannula comprising a cannula body having a distal end and a proximal end, the cannula body defining a first lumen that extends from the distal end to the proximal end and a second lumen that extends at least partially between the distal end and the proximal end, wherein in a plane perpendicular to a length of the first cannula, the first lumen has a larger cross-sectional area than the second lumen; and a second cannula receivable within the second lumen of the first cannula, the second lumen having a turn at its distal end that forces the second cannula to change direction at the turn where the second cannula exits the second lumen of the first cannula.

51. The cannula assembly of claim 50, wherein the second cannula has a diameter in a range from 5-10 French (F).

52. The cannula assembly of claim 51, wherein the second cannula has a diameter of 6 F.53- The cannula assembly of any one of claims 50-52, wherein the first cannula and the second cannula assembled together as the cannula assembly are insertable into a vessel of a patient through a common incision in the vessel.

54. The cannula assembly of claim 53, wherein: the first cannula and the second cannula assembled together as the cannula assembly and inserted into the vessel include the distal end of the first cannula that extends from the common incision in a first direction within the vessel and a distal end of the second cannula that extends from the common incision in an opposite second direction within the vessel; and the distal end of the first cannula extending in the first direction within the vessel and the distal end of the second cannula extending in the opposite second direction within the vessel are collectively configured to inhibit removal of the cannula assembly from the vessel.

55. The cannula assembly of any one of claims 50-54, wherein a lumen of the second cannula and the first lumen of the first cannula are configured to be in fluid communication with a common perfusion source.

56. The cannula assembly of any one of claims 50-55, wherein the second cannula includes one or more holes formed in a sidewall of the second cannula near a distal end of the second cannula.

57. The cannula assembly of any one of claims 50-56, further comprising a cannula hub coupled to the first cannula, the cannula hub comprising an output port coupled to the proximal end of the first cannula and an input port.

58. The cannula assembly of claim 57, wherein the cannula hub further comprises a flange between the output port and the input port, the flange configured to contact tissue of a patient at an insertion site of the cannula assembly to inhibit rotation of the cannula assembly while the cannula assembly is inserted in the patient.

59. The cannula assembly of claim 58, wherein the flange comprises one or more of a semi-rigid material and an adhesive material.

60. The cannula assembly of claim 58 or 59, wherein the flange is integrally formed with the cannula hub.

61. The cannula assembly of any one of claims 58-60, wherein the flange includes one or more flange holes configured for placement of sutures between the flange and the tissue of the patient through the one or more flange holes.

62. The cannula assembly of any one of claims 50-61, wherein a size of an opening at the distal end of the cannula assembly is larger than an aggregate size of one or more cannula blood flow exit ports.63- A method to insert a cannula into a blood vessel of a patient, the cannula comprising a cannula body having an open distal end, an intermediate segment proximal to the distal end in which a cannula blood flow exit port is formed, and a retainer coupled to the cannula body and movable between a stowed configuration and a deployed configuration, the method comprising: accessing the blood vessel of the patient with a needle; advancing a gui ewire through the needle into the blood vessel; removing the needle while retaining the guidewire in the blood vessel; advancing a dilator and the cannula along the guidewire into the blood vessel until: the distal end of the cannula is positioned to direct blood flow from the cannula in a first direction in the blood vessel; the cannula blood flow exit port is arranged to direct blood flow from the cannula in a second direction in the blood vessel that is opposite the first direction; and a retainer in a stowed configuration coupled to the cannula body is at least partially positioned within the blood vessel; removing the dilator; and altering the retainer to a deployed configuration in which a portion of the retainer is deployed within the blood vessel.

64. The method of claim 63, wherein altering the retainer to the deployed configuration occurs automatically in response to removal of the dilator from the cannula.

65. The method of claim 63 or 64, wherein: the retainer comprises a tube coupled to an exterior of the cannula body and an expandable structure retained within the tube in the stowed configuration such that altering the retainer to the deployed configuration comprises manually forcing the expandable structure out of the tube to the deployed configuration in the blood vessel.

66. The method of claim 65, wherein the expandable structure comprises a wire and in response to the expandable structure being forced out of the tube, the method further comprises the wire forming a framed protrusion that extends away from the intermediate segment near the cannula blood flow exit port and inhibits occlusion of the cannula blood flow exit port by a sidewall of the blood vessel.

67. The method of any one of claims 63-65, further comprising: coupling a proximal end of the cannula to a blood flow source; and flow ing blood through the cannula from the blood flow source and into the blood vessel in both the first direction and the second direction, including:flow ing blood out of the distal end of the cannula in the first direction in the blood vessel; and flow ing blood out of the cannula blood flow exit port in the second direction in the blood vessel that is opposite the first direction.

68. The method of claim 67, wherein: coupling the proximal end of the cannula to the blood flow source includes coupling the proximal end of the cannula to an output port of a cannula hub and coupling a first input port of the cannula hub to the blood flow source; and the method further comprises introducing an intravascular catheter into the blood vessel through a second input port of the cannula hub, the output port, and the cannula while maintaining blood flow into the blood vessel through the first input port, the output port, and the cannula.

69. The method of claim 68, wherein the cannula hub further comprises a flange between the output port and the first and second input ports, the method further comprising positioning the flange against tissue of a patient at an insertion site of the cannula to inhibit rotation of the cannula while the cannula is inserted in the patient.

70. The method of claim 69, wherein the flange includes one or more flange holes, the method further comprising placing sutures between the flange and the tissue of the patient through the one or more flange holes.

71. The method of any one of claims 63-70, wherein a size of an opening at the distal end of the cannula is larger than an aggregate size of one or more cannula blood flow exit ports, the method further comprising flowing more blood flow7through the distal end of the cannula than through the one or more cannula blood flow7exit ports.

72. A method to insert a cannula into a blood vessel of a patient, the cannula comprising a cannula body having an open distal end and a balloon coupled to the cannula body proximal to the distal end, the balloon including a proximal surface that defines one or more balloon blood flow exit ports, the method comprising: accessing the blood vessel of the patient with a needle; advancing a guidewire through the needle into the blood vessel; removing the needle while retaining the guidewire in the blood vessel; advancing a dilator and the cannula along the guidewire into the blood vessel until: the distal end of the cannula is positioned to direct blood flow7from the cannula in a first direction in the blood vessel; and the balloon is positioned in the blood vessel with the one or more balloon blood flow exit ports defined in the proximal surface of the balloonpositioned to direct blood flow from the cannula in a second direction in the blood vessel that is opposite the first direction; and removing the dilator.

73. The method of claim 72, further comprising: coupling a proximal end of the cannula to a blood flow source; and flowing blood through the cannula from the blood flow source and into the blood vessel, including: flowing blood out of the distal end of the cannula in the first direction in the blood vessel; and flowing blood out of one or more cannula blood flow exit ports defined in the cannula into the balloon; and flowing blood through the balloon from the cannula and into the blood vessel, including flowing blood out of the one or more balloon blood flow exit ports of the balloon in the second direction in the blood vessel that is opposite the first direction.

74. The method of claim 73 , wherein : coupling the proximal end of the cannula to the blood flow source includes coupling the proximal end of the cannula to an output port of a cannula hub and coupling a first input port of the cannula hub to the blood flow source; and the method further comprises introducing an intravascular catheter into the blood vessel through a second input port of the cannula hub, the output port, and the cannula while maintaining blood flow into the blood vessel through the first input port, the output port, and the cannula.

75. The method of any one of claims 72-74, further comprising collapsing the balloon against the cannula body as the balloon coupled to the cannula is inserted through an incision into the blood vessel while advancing the dilator and the cannula along the guidewire and into the blood vessel.

76. The method of any one of claims 72-75, wherein after the balloon is positioned in the blood vessel, the method further comprises filling and expanding the balloon wit h i n the blood vessel w ith blood from a blood flow source.

77. The method of any one of claims 72-76, further comprising introducing priming fluid into the balloon prior to removing the dilator.

78. The method of claim 77, wherein the dilator is configured with a groove extending longitudinally along at least a portion of an exterior of the dilator to create a priming fluid channel between the outside of the dilator and the inside of the cannula body,the priming fluid channel in fluid communication w ith a cannula blood flow exit port defined in the cannula, wherein introducing priming fluid into the balloon comprises introducing priming fluid into the balloon through the priming fluid channel and the cannula blood flow exit port.

79. The method of claim 77, wherein the dilator includes a priming fluid hole extending radially therethrough that is configured to be aligned with a cannula blood flow exit port defined in the cannula into the balloon, wherein introducing priming fluid into the balloon comprises introducing priming fluid into the balloon through a main lumen of the dilator, the priming fluid hole, and the cannula blood flow exit port.

80. The method of any one of claims 72-76, wherein the dilator includes a priming fluid lumen extending longitudinally through at least a portion of the dilator and in fluid communication with a priming fluid hole formed in the dilator that is configured to be aligned with a cannula blood flow exit port defined in the cannula into the balloon, wherein introducing priming fluid into the balloon comprises introducing priming fluid into the balloon through the priming fluid lumen of the dilator, the priming fluid hole, and the cannula blood flow exit port.

81. The method of any one of claims 74-80, wherein the cannula hub further comprises a flange between the output port and the first and second input ports, the method further comprising positioning the flange against tissue of a patient at an insertion site of the cannula to inhibit rotation of the cannula while the cannula is inserted in the patient.

82. The method of claim 81, wherein the flange includes one or more flange holes, the method further comprising placing sutures between the flange and the tissue of the patient through the one or more flange holes.

83. The method of any one of claims 72-82, wherein one or more cannula blood flow exit ports in the cannula are at least as large as the one or more balloon blood flow exit ports.

84. The method of any one of claims 72-83, wherein a size of an opening at the distal end of the cannula is larger than an aggregate size of one or more cannula blood flow exit ports in the cannula.

85. A method to insert a cannula assembly into a blood vessel of a patient, the cannula assembly comprising a first cannula having a cannula body w ith a distal end and a proximal end, the cannula body defining a first lumen that extends from the distal end to the proximal end and a second lumen that extends at least partially between the distal end and the proximal end, the method comprising: accessing a blood vessel of a patient with a needle;advancing a gui ewire through the needle into the blood vessel; removing the needle while retaining the guidewire in the blood vessel; advancing a dilator and the first cannula along the guidew ire into the blood vessel until: the distal end of the cannula body of the first cannula is positioned to direct blood flow’ from the first cannula in a first direction in the blood vessel; and a distal end of the second lumen is positioned within the blood vessel while a proximal end of the second lumen remains outside the blood vessel; advancing a second cannula through the second lumen of the first cannula until distal and proximal ends of the second cannula extend from the distal and proximal ends of the second lumen, the distal end of the second lumen having a turn that forces the second cannula to change direction at the turn where the second cannula exits the second lumen, the distal end of the second cannula positioned to direct blood flow from the second cannula in a second direction in the blood vessel that is opposite the first direction; and removing the dilator.

86. The method of claim 85, further comprising: coupling the proximal end of the first cannula to a blood flow’ source; coupling the proximal end of the second cannula to the blood flow source; flowing blood through the first cannula from the blood flow’ source and into the blood vessel, including flowing blood out of the distal end of the first cannula in the first direction in the blood vessel; and flowing blood through the second cannula from the blood flow’ source and into the blood vessel, including flowing blood out of the distal end of the second cannula in the second direction in the blood vessel that is opposite the first direction.

87. The method of claim 86, wherein: coupling the proximal end of the first cannula to the blood flow’ source includes coupling the proximal end of the first cannula to an output port of a cannula hub and coupling a first input port of the cannula hub to the blood flow’ source; and the method further comprises introducing an intravascular catheter into the blood vessel through a second input port of the cannula hub, the output port, and the first cannula while maintaining blood flow’ into the blood vessel through the first input port, the output port, and the cannula assembly.

88. The method of claim 87, wherein the cannula hub further comprises a flange between the output port and the first and second input ports, the method further comprising positioning the flange against tissue of a patient at an insertion site of the cannula assembly to inhibit rotation of the cannula assembly while the cannula assembly is inserted in the patient.

89. The method of claim 88, wherein the flange includes one or more flange holes, the method further comprising placing sutures between the flange and the tissue of the patient through the one or more flange holes.

90. The method of any one of claims 85-89, wherein: the second cannula includes one or more cannula blood flow exit ports formed in a sidewall of the second cannula closer to the distal end of the second cannula than the proximal end of the second cannula; and advancing the second cannula through the second lumen of the first cannula includes advancing the second cannula through the second lumen of the first cannula until the one or more cannula blood flow exit ports formed in the sidewall of the second cannula are positioned distal to the distal end of the second lumen of the first cannula.

91. The method of any one of claims 85-90, wherein a size of an opening at the distal end of the cannula assembly is larger than an aggregate size of the one or more cannula blood flow exit ports formed in the sidewall of the second cannula.

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