WO2017202881A1

WO2017202881A1 - Aortic devices and methods

Info

Publication number: WO2017202881A1
Application number: PCT/EP2017/062481
Authority: WO
Inventors: Amit ASHKENAZI
Original assignee: Keystone Heart Ltd.; Swat Medical Ab
Priority date: 2016-05-23
Filing date: 2017-05-23
Publication date: 2017-11-30

Abstract

An aortic cannula comprising an external portion, an intraaortic portion configured to span a cross-section of the aorta, and a lumen that terminates in the intraaortic portion.

Description

SPECIFICATION

TITLE : AORTIC DEVICES AND METHODS

BACKGROUND OF THE DISCLOSURE

Various types of surgical procedures are performed on the heart, many of which involve replacement of the aortic valve. Surgical aortic valve replacement (SAVR) requires cardiopulmonary bypass, which involves connecting the

patient's circulation to a heart-lung machine. This process requires insertion of an aortic cannula by puncturing the ascending aorta. Arrest of cardiac function, e.g., by

infusion of cardioplegia, is also required. During the operation, blood is pumped into the circulation via the aortic cannula and flows out through a right atrial

cannulation for recirculation through the heart-lung machine and back into the patient.

Throughout the course of aortic valve replacement surgery, there is a high risk of dislodging plaque or other particulate matter in the heart or ascending aorta. Upon restarting the heart and connecting it with the circulation, these emboli can flow into the circulation and obstruct blood flow and oxygen supply to critical tissues. Reduction and prevention of emboli is an important consideration in cardiac procedures, such as aortic valve replacement surgery.

Therefore, there is a clear need for methods and devices to achieve a variety of tasks involved in cardiac procedures, such as aortic valve replacement surgery.

SUMMARY OF THE INVENTION

In one aspect, the disclosure features an aortic cannula including an external portion, and intraaortic portion configured to span a cross-section of the aorta, and a lumen that terminates in the aortic portion. The intraaortic portion may further include a frame that defines the periphery of the filter (e.g., an embolic filter) . In some examples, the frame is configured to approximate an inner circumference of the aorta (e.g., contact the majority or entirety of the inner circumference, or run substantially concentrically to the inner circumference) . In some examples, the frame is curved (e.g., substantially conical) . It may include or be formed of a plurality of woven fibers (e.g., mesh) or made from metal (e.g., nitinol or stainless steel), polymer, or a combination thereof.

In some examples, the intraaortic portion includes an intraaortic tube through which one or more liquids (e.g., blood or cardioplegia) can be infused. In some examples, a blood infusion line runs through the aortic cannula and terminates at a downstream-facing outlet on the intraaortic portion (e.g., an intraaortic tube) of the cannula. A frame actuating element may also run through the aortic cannula, which can be operatively connected to the frame, e.g., for actuation (e.g., positional manipulation or expansion) of the frame.

In some examples, the intraaortic portion further includes an impermeable membrane configured to span the cross-section of the aorta (e.g., at the upstream side, downstream side, or both, of the frame) . The impermeable membrane may be part of a balloon (e.g., a toroidal balloon) .

In some examples, the inflation of the balloon expands the frame to approximate an inner circumference of the aorta. The balloon can be operatively connected to an inflation line that runs through the external portion of the aortic cannula, terminating at the interior of the balloon (e.g., at one or more outlets of the intraaortic tube) . Inflation of the balloon can form a conduit for liquid flow (e.g., blood flow or cardioplegia flow) from the intraaortic tube (e.g., through a hole created by a toroidal structure) . In some examples, a cardioplegia line runs through the aortic cannula and terminates at an upstream-facing outlet on the intraaortic tube. Cardioplegia can flow from the

upstream-facing outlet toward the heart, and blood can flow from the downstream-facing outlet toward the aortic arch and through the patient's circulation.

In some examples, the blood has passed through a heart- lung machine.

In another aspect, the disclosure provides an aortic cannula comprising an intraaortic portion, the intraaortic portion comprising a balloon configured to span a cross- section of the aorta.

In a further aspect, the disclosure features a method of providing blood to the aorta of a patient. The method includes the steps of making an opening (e.g., an aortotomy) in the aorta of the patient; inserting an intraaortic portion of an aortic cannula through the opening in the aorta;

expanding the intraaortic portion to span a cross-section of the aorta; and infusing blood through the aortic cannula, thereby providing blood to the aorta of the patient. In some examples, the intraaortic portion includes a frame, which is expanded, e.g., to span the cross-section of the aorta. The intraaortic portion may also include both a frame and a balloon, either or both of which can be expanded to span a cross-section of the aorta.

In some examples, the method includes inflating the balloon. In some examples, the method includes infusing blood into the patient (e.g., through a blood infusion line

terminating at a downstream-facing outlet at the intraaortic tube) .

In other examples, the method includes infusing a cardioplegia to the patient (e.g., through a cardioplegia line terminating at an upstream-facing (i.e., toward the heart) outlet at the intraaortic tube) . In some examples, the disclosure provides a method of removing the aortic cannula by deflating the balloon prior to collapsing the frame (e.g., to collect any loose emboli from the heart or ascending aorta upon restarting the heart) .

In a further aspect, the disclosure provides a method of providing cardioplegia to a patient by infusing

cardioplegia through a toroidal balloon.

In another aspect, the disclosure provides an aortic cannula including an external portion, an intraaortic portion having a dual lumen (e.g., for infusion of cardioplegia and/or blood), and a balloon configured to span a cross- section of the aorta.

DEFINITIONS

As used herein, an "aortic cannula" is a tubular member for liquid infusion that is inserted into an artery through an incision in the aortic wall (e.g., an aortotomy) .

As used herein, the term "expand, " "expands, "

"expanded, " or "expanding" refers to an increase in one or more dimensions of all or a part of an element. As a non- limiting example, an intraaortic portion of a cannula is expanded, e.g., after insertion into an aorta, when an element of the intraaortic portion (e.g., a filter frame) increases in width relative to its configuration during, or prior to, its insertion into the aorta.

As used herein, to "span" a cross-sectional area means to occupy the space at or near the boundaries of the area and a majority of the area of the plane within the boundaries.

As used herein, to "approximate" is to have a shape approximately equal to a reference shape.

An element approximates a circumference if the element is disposed along, e.g., runs substantially concentrically to, the circumference. As used herein, a material is "impermeable" if water does not pass therethrough under physiological temperature and pressure.

As used herein, "patient" refers to a mammal (e.g., a human) .

As used herein, the term "toroidal" refers to a three- dimensional shape substantially similar to a torus, i.e., a donut . In any one dimension, a substantially circular object having a void anywhere within its perimeter is said to be "toroidal."

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings are illustrative of particular examples of the present disclosure and are not limiting to various examples encompassed by the present disclosure.

Figure 1 is a schematic showing an offset side view of an aortic cannula having an expanded frame, an inflated balloon, and a filter.

Figure 2 is a schematic showing an offset top view of an aortic cannula having an expanded frame, an inflated balloon, and a filter.

Figure 3 is a schematic showing an intraaortic cannula having an intraaortic portion secured in an aorta in an unexpanded configuration. Arrows indicate the direction of blood flow.

Figure 4 is a schematic showing an aortic cannula having an intraaortic portion in an expanded configuration, including an expanded frame, an inflated balloon, and a filter. Solid arrows indicate the direction of blood flow, and dotted arrows indicate the direction of cardioplegia flow .

Figure 5 is a schematic showing an aortic cannula having an intraaortic portion in an expanded configuration, including an expanded frame, a filter, and deflated balloon. Arrows indicate the direction of blood flow.

DESCRIPTION OF EXAMPLES

The present disclosure relates to aortic cannulas and method of using aortic cannulas as part of intravascular procedures (e.g., heart surgery, e.g., surgical aortic valve replacement (SAVR) ) . Such procedures involve a series of complex steps, including inducing cardiac arrest, connecting the patient to a heart-lung machine, and performing the procedure itself, each of which presents a significant risk of perturbing particulates (e.g., blood clots, calcified debris, and emboli) . Dislodged particles can flow downstream and impede circulation to vital organs, such as the brain (e.g., by flowing into the left subclavian artery, left common carotid artery, or innominate artery) . The present disclosure provides an aortic cannula equipped to perform one or more steps associated with cardiac procedures (e.g.,

SAVR) .

Cannulas

The disclosure features an aortic cannula with a specialized intraaortic portion (i.e., a portion configured to be inserted in the aortic lumen) . The intraaortic portion can be an assembly of elements including, e.g., a frame configured to span a cross-section of the aorta.

The frame of the intraaortic portion is configured to expand or be expanded after insertion into an aorta to span the cross-section of the aorta (e.g., from a circular

structure along the circumference of the inner aortic wall) . The frame can provide support for various additional elements within the aortic lumen. For example, the frame can support a filter, such as an embolic filter (e.g., by suspension, e.g., by attachment to the perimeter of the filter, thereby defining the perimeter of the filter) . To facilitate

insertion into an aorta, the frame can be flexible to allow all or a portion of the frame to be constrained along a longitudinal axis and held within the cannula, e.g., during insertion and removal. Flexible, biocompatible materials with mechanical properties suitable for the composition of the frame are known in the art include, e.g., plastic, elastomer, ceramic, metal or metal alloy (including stainless steel, platinum, tantalum, cobalt-chromium alloy, or shape-memory material, e.g., nitinol) , biocompatible polymer (e.g., polyethylene, high molecular weight polyethylene,

polystyrene, or polypropylene), superelastic material, or composites thereof. In some examples, the frame includes a metal (e.g., stainless steel) core that may be coated with a biocompatible polymer.

The frame can have an intrinsic shape suitable to facilitate expansion into, and collapsibility from, a

circular shape. For example, the frame can include one or more intrinsic bends, as shown in Figure 1. Intrinsic bends can determine the shape of the filter in an unconstrained

(e.g., expanded) configuration. As a non-limiting example, a frame may be an elongated element having two ends, each end disposed in the lumen of an external portion of the cannula, creating a loop at the intraaortic portion. This frame can be circular to allow for the apposition of the frame (and elements attached to or supported by the frame, e.g., a filter) against the internal aortic walls. The frame can have any dimensions suitable to span the cross-section of a patient's aorta (e.g., a diameter of about 1.0 cm, 1.1 cm, 1.2 cm, 1.3 cm, 1.4 cm, 1.5 cm, 1.6 cm, 1.7 cm, 1.8 cm, 1.9 cm, 2.0 cm, 2.1 cm, 2.2 cm, 2.3 cm, 2.4 cm, 2.5 cm, 2.6 cm, 2.7 cm, 2.8 cm, 2.9 cm, 3.0 cm, 3.1 cm, 3.2 cm, 3.3 cm, 3.4 cm, 3.5 cm, 3.6 cm, 3.7 cm, 3.8 cm, 3.9 cm, 4.0 cm, 4.1 cm, 4.2 cm, 4.3 cm, 4.4 cm, 4.5 cm, 4.6 cm, 4.7 cm, 4.8 cm, 4.9 cm, 5.0 cm, 5.1 cm, 5.2 cm, 5.3 cm, 5.4 cm, 5.5 cm, 5.6 cm, 5.7 cm, 5.8 cm, 5.9 cm, 6.0 cm, 6.1 cm, 6.2 cm, 6.3 cm, 6.4 cm, 6.5 cm, 6.6 cm, 6.7 cm, 6.8 cm, 6.9 cm, 7.0 cm, 7.1 cm, 7.2 cm, 7.3 cm, 7.4 cm, 7.5 cm, 7.6 cm, 7.7 cm, 7.8 cm, 7.9 cm, 8.0 cm, or greater) .

The two ends of the frame can be attached to one or more frame actuating elements within the lumen of the

external portion of the cannula. Frame actuating elements can run from the frame, through the external portion of the cannula, to the operator for remote manipulation of the frame. Frame actuating elements can include wires, rods, and the like.

The frame can function to support or suspend a filter. The filter can be attached to all or a portion of the

periphery of the frame. In some examples, the frame defines the periphery of the filter, e.g., by attachment of a

circular periphery of a curved filter to the circular

configuration of the frame. The filter can be attached to the frame by wires, which can be inserted into connection points on the distal latch and optionally secured by, e.g., a loop, a clamp, sewing, welding, or a physiologically suitable adhesive. Other modes of attachment suitable for the filter- frame attachment are known in the art.

Various filter configurations are suitable for the present disclosure. In general, a filter can be convex in shape (e.g., dome-shaped, semi-spherical, substantially conical, or any combination thereof) . In some examples, the filter is configured to be suspended across the entire cross- section of the aorta, such that, in its expanded

configuration, all possible routes of blood flow traverse the filter at a point between the heart and the descending aorta. The filter can have dimensions suitable to achieve such properties. For example, The filter can have any dimensions suitable to span the cross-section of a patient's aorta when suspended from the frame (e.g., a diameter of about 1 .0 cm, 1 .1 cm, 1 .2 cm, 1 .3 cm, 1.4 cm, 1.5 cm, 1.6 cm, 1.7 cm, 1.8 cm, 1.9 cm, 2.0 cm, 2.1 cm, 2.2 cm, 2.3 cm, 2.4 cm, 2.5 cm, 2.6 cm, 2.7 cm, 2.8 cm, 2.9 cm, 3.0 cm, 3.1 cm, 3.2 cm,

3.3 cm, 3.4 cm, 3.5 cm, 3.6 cm, 3.7 cm, 3.8 cm, 3.9 cm, 4.0 cm, 4.1 cm, 4.2 cm, 4.3 cm, 4.4 cm, 4.5 cm, 4.6 cm, 4.7 cm,

4.8 cm, 4.9 cm, 5.0 cm, 5.1 cm, 5.2 cm, 5.3 cm, 5.4 cm, 5.5 cm, 5.6 cm, 5.7 cm, 5.8 cm, 5.9 cm, 6.0 cm, 6.1 cm, 6.2 cm,

6.3 cm, 6.4 cm, 6.5 cm, 20 6.6 cm, 6.7 cm, 6 .8 cm, 6.9 cm,

7.0 cm, 7.1 cm, 7.2 cm, 7.3 cm, 7.4 cm, 7.5 cm, 7.6 cm, 7.7 cm, 7.8 cm, 7.9 cm, 8.0 cm, or greater) . The length of the filter can be any length that can be sufficiently collapsed for insertion and retrieval of the cannula.

The filter can be made, wholly or partially, from a plurality of woven fibers, such as a mesh. The filter can include, e.g., a mesh fabricated with metal or metal alloy wire (e.g., nitinol) , polymer wire or fibers (e.g., woven or braided fibers, e.g., nylon), a perforated film (e.g., a metal or metal alloy film (e.g., nitinol) or polymer film, or a combination of both. One or more lateral dimensions of the filter's pores can be between 50 and 1000 microns (e.g., 100, 200, 300, 400, 500, 600, or more microns) . The size of the pores allows the passage of blood cells (e.g., red blood cells (erythrocytes) , white blood cells (leukocytes) , and/or platelets (thrombocytes)) and plasma, while being impermeable to particles, e.g., emboli, larger than the pore dimensions. Particles, e.g., emboli, filtered by the filter of the present disclosure are typically particles larger in one or more dimensions than an aperture of the pores of the filter. Filtered particles, e.g., emboli, may be sized to have a dimension greater than 50 μιτι, e.g., 50 μιτι, 60 μιτι, 70 μπι, 80 μπι, 90 μπι, 100 μπι, 200 μπι, 300 μπι, 400 μπι, 500 μπι, or 1000 μιη or more.

The aortic cannula may additionally include a lumen for blood infusion. In particular, the external portion of the cannula may include a blood infusion line (e.g., within the cannula lumen) , which can provide blood flow from a heart- lung machine to the patient's aorta. A blood infusion line may be substantially similar to a conventional aortic cannula known in the art. It may have suitable dimensions to enable pulsatile blood flow at physiological pressures, flow rates, and frequencies, and it can be made of a suitable

biocompatible material (e.g., polymer, e.g., flexible plastic tubing) . The blood infusion line may be a structurally independent tube within, or as part of, the external portion of the cannula, or it may be integrated as a segment of the external portion of the cannula. The blood infusion line terminates (e.g., at a point that ejects or releases the infused blood) at an intraaortic tube (e.g., at the upstream end of the filter, or substantially within the cross-section spanned by the frame, as shown in Figure 2) . The terminus of the blood infusion line can be a downstream-facing outlet (e.g., on the intraaortic tube, as shown in Figure 2) .

The device may also include a lumen to infuse

cardioplegia toward the heart to induce cardiac arrest.

Therefore, the external portion of the cannula may include a cardioplegia line, which may connected to a cardioplegia supply (e.g., a pump, bag, or syringe) . The cardioplegia line may have suitable dimensions to enable adequate infusion rates, and it can be made of a suitable material (e.g., polymer, e.g., flexible plastic tubing). The cardioplegia line may be a structurally independent tube within, or as part of, the external portion of the cannula, or it may be integrated as a segment of the external portion of the cannula. The cardioplegia line terminates (e.g., at a point that infuses the cardioplegia) at the intraaortic tube. The terminus of the cardioplegia line can be an upstream-facing outlet (e.g., on the intraaortic tube, as shown in Figure 1) .

To accommodate infusion of fluid (e.g., cardioplegia or blood) , the intraaortic portion of the cannula may include an impermeable membrane (i.e., a membrane that is impermeable to water or blood) . The membrane can be configured to span a cross-section of the aorta. In some examples, the membrane is a balloon, and the inflated balloon is configured to span the aorta. The impermeable membrane (e.g., balloon) is configured to replace a clamp, which is conventionally used to isolate the heart from the downstream circulation (e.g., via the aorta) . The impermeable membrane (e.g., balloon) provides a seal between the blood infusion site and the heart, which prevents backflow of blood toward the left ventricle during operation and prevents cardioplegia from accessing the patient's circulation. In some examples, the inflated balloon provides this seal. The balloon can be configured to inflate into a shape that permits flow of a liquid (e.g.,

cardioplegia and/or blood) from the cannula. In particular, the disclosure provides a balloon that is inflatable into a toroidal shape, such that flow of one or more liquids from the intraaortic tube outwards e.g., upstream or downstream of the intraaortic tube) freely passes through a conduit formed by the balloon (see Figures 1 and 2) .

The toroidal balloon may be configured to be positioned on both the upstream and downstream ends of the intraaortic tube upon inflation, and its shape may be symmetrical or asymmetrical along the plane defined by the aorta's cross- section. In some examples, the balloon is asymmetrically configured with a bulbous shape on the upstream side of the frame and/or a flat shape on the downstream side. This shape is designed to facilitate unimpeded bloodflow outward from the aorta within the space directly downstream of the frame, such as a branching (e.g., innominate) artery. The balloon can be made from various biocompatible materials (e.g., nylon, polyvinyl chloride, polyester, polyolefin,

polyurethane, or composites thereof) and may be connected to an inflation line running through the external portion of the cannula. The inflation line may have suitable dimensions to enable adequate infusion rates, and it can be made of a suitable biocompatible material (e.g., polymer). The inflation line may be a structurally independent tube within, or as part of, the external portion of the cannula, or it may be integrated as a segment of the external portion of the cannula. The inflation line terminates (e.g., at a point that releases a fluid, e.g., saline solution, such as sodium chloride in water) at one or more termini within the interior of the balloon.

All elements of the intraaortic portion of the cannula can be made from biocompatible (e.g., non-thrombogenic) materials according to methods known in the art. Additional features can be readily added to any one or more of the elements of the cannula, e.g., as may be beneficial under unique anatomical circumstances or surgical procedures.

The external portion of the cannula may be configured to be connected to a heart-lung machine and/or source of cardioplegia .

Methods

The disclosure provides methods of using a cannula having a specialized intraaortic portion. Specifically, the methods can be used to provide blood and/or cardioplegia to the aorta of a patient. The intraaortic portion can be inserted into an artery through an incision (e.g., an

aortotomy) on the aortic wall, immediately adjacent to the cross section that is to be spanned by the filter. Upon positioning within the aorta, the intraaortic portion can be expanded, and blood can be infused into the patient's

circulation through the aortic cannula.

Methods of inserting the aortic cannula of the present disclosure are analogous to methods that are routine in the art. A purse-string suture configuration can be established, followed by an incision, to create an aortotomy, through which the intraaortic portion of the cannula can be inserted. Other methods are known in the art . The disclosure provides methods for expanding the intraaortic portion (e.g., expanding the frame, balloon, or both) to span the cross-section of the aorta. In one example, the method includes expanding the frame to span the cross- section of the aorta. An operator (e.g., surgeon or

assistant) expands the frame by manipulating a frame

actuating element from the external terminal of the cannula. The frame actuating element enables the operator, e.g., to push all or a portion of the frame out from a lumen (e.g., of the external portion of the cannula) into the aorta,

releasing constriction of the frame and allowing it to take its intrinsic shape (e.g., a circle) . This frame actuation can position the filter to prevent passage of any emboli.

Additionally or alternatively, the operator can expand an impermeable membrane to span the cross-section of the aorta (e.g., at or near the cross-section spanned by the frame) . In one example, expansion of the impermeable membrane is achieved by inflating a balloon. The disclosure provides methods of inflating the balloon through an inflation line running along or through the external portion of the cannula. The balloon can be inflated using any fluid compatible with the balloon material, e.g., a liquid (e.g., saline solution, e.g., sodium chloride in water) or an inert gas (e.g., air, oxygen, nitrogen, argon, or carbon dioxide) . An inflation source (e.g., a liquid pump, e.g., peristaltic pump,

compressed gas tank, air pump, or air compressor) may be connected to the inflation line according to methods known in the art. A balloon can be inflated to a pressure from 10 to 1,000 pounds per square inch (p.s.i.) (e.g., 10 p.s.i., 20 p.s.i., 30 p.s.i., 40 p.s.i., 50 p.s.i., 60 p.s.i., 70 p.s.i., 80 p.s.i., 90 p.s.i., 100 p.s.i., 110 p.s.i., 120 p.s.i., 130 p.s.i., 140 p.s.i., 150 p.s.i., 160 p.s.i., 170 p.s.i., 180 p.s.i., 190 p.s.i., 200 p.s.i., 210 p.s.i., 220 p.s.i., 230 p.s.i., 240 p.s.i., 250 p.s.i., 260 p.s.i., 270 p.s.i., 280 p.s.i., 290 p.s.i., 300 p.s.i., 400 p.s.i., 500 p.s.i. or higher) to achieve an adequate seal between the upstream and downstream aorta. Fluid pressures required for impermeability may vary, depending on the shape of the balloon .

Methods of infusing blood into the aorta of a patient are well established and can be adapted to the devices of the present disclosure. A heart-lung machine pumps blood, in a physiological manner, through the external portion of the cannula (e.g., the blood infusion line) into the intraaortic portion of the cannula and out the downstream-facing outlet into the patient's circulation. In some examples, the

downstream-facing outlet is configured to infuse the blood through a toroidal balloon. An additional cannula can be placed near the patient's right atrium to recover the

circulated blood to be shunted around the heart, through the heart-lung machine, according to routine methods.

Methods of administering cardioplegia are also provided herein. Any suitable cardioplegia (e.g., a solution of sodium bicarbonate, potassium chloride, mannitol, and isolyte-S, pH=7.4), with or without a prior treatment (e.g., with a solution of lidocaine, nitroglycerin, and albumin) can be used in the methods of the present disclosure. Cardioplegia can be infused through the external cannula at, e.g., the cardioplegia line, and infused upstream of the intraaortic tube toward the heart. In some examples, the disclosure provides methods of infusing cardioplegia through a toroidal balloon of the disclosure. At any point during the procedure, or upon completion of the operation, the cardioplegia line can function to deliver any necessary additional agent, e.g., a reperfusate or a therapeutic.

The disclosure further provides methods for removal of the intraaortic portion of the cannula. In some examples of the methods of the disclosure, the balloon is deflated, e.g., by applying negative pressure to the external terminus of the inflation line, e.g., by pumping the gas out the line. Deflation of the balloon may constrict one or more (e.g., one, two, or three) dimensions of the balloon such that blood flow is substantially restored (e.g., the cross-section of the aorta is opened by, e.g., 40%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or more) . Upon deflation of the balloon and restoration of blood flow, the frame and/or filter may be left in place (e.g., spanning the cross-section of the aorta) . In this configuration, the filter is

configured to catch any particles (e.g., emboli), dislodged upstream of the intraaortic portion of the cannula prior to blood flow restoration.

To remove the intraaortic portion of the cannula from the aorta, an operator can manipulate the frame actuating element from the external terminal of the external portion of the cannula. As a non-limiting example, an operator may retract all or a portion of the frame into the external portion of the cannula by pulling the frame actuating element (e.g., a wire or rod) away from the aorta. Retraction of all or part of the frame into the external portion of the cannula may constrict or collapse the frame (e.g., having a flexible composition) along the intraaortic tube, giving the entirety of the intraaortic portion a transverse cross-section similar to the diameter of the aortotomy. The intraaortic portion of the device can then be pulled from the aorta and the

aortotomy can be closed according to routine methods.

EXAMPLES

In the following description, various examples of the disclosure will be described. For purposes of explanation, specific examples are set forth in order to provide a

thorough understanding of at least one example of the

disclosure. However, it will also be apparent to one skilled in the art that other examples of the disclosure are not limited to the examples described herein. Furthermore, wellknown features or processes may be omitted or simplified in order not to obscure examples of the disclosure described herein .

Referring to Figure 3, an aortotomy is created at the superior wall of the aortic arch and the intraaortic portion of the cannula is inserted through the incision, into the aorta. The cannula is advanced through the aortotomy until the terminal end of the cannula contacts the inferior luminal aortic wall, at a position substantially opposite of the aortotomy. Figure 3 shows the intraaortic portion in its unexpanded configuration, constrained in a rod shape to minimally obstruct the flow of blood through the aorta.

Referring to Figure 4, the balloon is inflated,

expanding the frame to span the aortic cross-section adjacent to the aortotomy. Alternatively, the frame can be expanded independent from the balloon inflation. This expansion of the frame opens the filter, which similarly spans the aortic cross section. The toroidal shape of the balloon creates a conduit through which the cardioplegia and blood can flow outward from the intraaortic tube. The flat surface of the balloon on the downstream side of the device allows blood to access the innominate artery. Cardioplegia is administered through a cardioplegia line within the cannula and flows into the aorta from an upstream-facing outlet of the intraaortic tube. A separate blood infusion line within the cannula provides blood from a heart-lung machine to the patient's circulation. The infused blood exits the cannula through the intraaortic tube at a downstream-facing outlet, opposite to the upstream-facing outlet.

Upon completion of the primary surgical procedure, e.g., aortic valve replacement, the aortic cannula is

reconfigured to filter any debris dislodged at the heart or ascending aorta. Referring to Figure 5, the balloon is deflated by retrograde pumping of air or liquid through the inflation line within the cannula. Deflation collapses the balloon around the intraaortic tube, allowing blood to freely flow from the heart, past the cross-section defined by the spanning of the frame, and through the filter. The filter is configured to permit the flow of blood and endogenous blood components (e.g., serum, blood cells, and platelets) without significant resistance, but it catches larger particulate matter (e.g., emboli) . The blood can be filtered for a duration of time sufficient to prevent emboli from flowing downstream of the device.

The frame and filter are retracted into the cannula by manipulation of the frame actuating element through the cannula. The operator pulls the frame actuating element to constrict the flexible frame into the cannula lumen,

collapsing the terminal region of the frame along the

intraaortic tube and deflated balloon, as shown in Figure 3. After the intraaortic portion is collapsed along a

longitudinal axis, the operator removes the intraaortic portion from the aortic lumen through the aortotomy and seals the aortic wall by tightening the purse-string sutures.

It will be appreciated by persons skilled in the art that examples of the disclosure are not limited by what has been particularly shown and described above. Various

modifications of the described modes for carrying out the disclosure are intended to be within the scope of the

disclosure .

Claims

1. An aortic cannula comprising an external portion, an intraaortic portion configured to span a cross- section of the aorta, and a lumen that terminates in the intraaortic portion.

2. The cannula of claim 1, wherein the intraaortic

portion further comprises a frame that defines the periphery of a filter.

3. The cannula of claim 2, wherein the frame

approximates an inner circumference of the aorta.

4. The cannula of an of claims 2 or 3, wherein the

filter is curved.

5. The cannula of any one of claims 2-4, wherein the filter comprises a plurality of woven fibers.

6. The cannula of any one of claims 2-5, wherein the filter comprises a mesh.

7. The cannula of any one of claims 2-6, wherein the filter is nitinol.

8. The cannula of any one of claims 1-7, further

comprising a blood infusion line that terminates at a downstream-facing outlet on an intraaortic tube.

9. The cannula of any one of claims 1-8, further

comprising a frame actuating element operatively connected to the frame.

10. The cannula of any one of claims 1-9, wherein the intraaortic portion further comprises an impermeable membrane configured to span a section of the aorta.

11. The cannula of claim 10, wherein the intraaortic portion further comprises a balloon comprising the impermeable membrane.

12. The cannula of claim 11, further comprising an

inflation line terminating at the interior of the balloon .

13. The cannula of claim 11 or 12, whereupon inflation of the balloon, a conduit for liquid flow from the intraaortic tube is formed.

14. The cannula of claim 13, wherein the balloon is toroidal in shape.

15. The cannula of any one of claims 1-14, further

comprising a cardioplegia line that terminates at an upstream-facing outlet on the intraaortic tube.

16. The cannula of any one of claims 11-15, whereupon inflation of the balloon, the intraaortic portion spans the cross-section of the aorta.

17. An aortic cannula comprising an intraaortic

portion, the intraaortic portion comprising a balloon configured to span a cross-section of the aorta .

18. The cannula of claim 17, wherein the intraaortic portion comprising a dual lumen.

19. A method of providing blood to the aorta of a

patient, the method comprising the steps of:

a. making an opening in the aorta of the patient; b. inserting an intraaortic portion of the aortic cannula of claim 1 through the opening in the aorta; c. expanding the intraaortic portion to span a cross-section of the aorta; and

d. infusing blood through the aortic cannula, thereby providing blood to the aorta.

20. The method of claim 19, comprising inflating the balloon .

21. The method of claim 19 or 20, further comprising infusing blood.

22. The method of claim 20 or 21, further comprising infusing the cardioplegia.

23. The method of any one of claims 19-22, further

comprising deflating the balloon prior to collapsing the frame .

24. The method of any one of claims 19-23, wherein the blood has passed through a heart-lung machine.

25. A method of providing cardioplegia to a patient, comprising injecting the cardioplegia through a toroidal balloon.

26. The cannula of any one of claims 1-18, wherein the cross-section of the aorta is adjacent to an

aortotomy .