CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims the benefit of the filing date of U.S. Provisional Patent

Application No. 62/202,484, filed August 7, 2015, the disclosure of which is hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] The present disclosure relates to an apparatuses, kits and methods for improving venous blood flow into the pulmonary arteries.

[0003] An operation known as the Fontan procedure is performed to treat several complex congenital heart abnormalities including tricuspid atresia, pulmonary atresia with intact ventricular septum, hypoplastic left heart syndrome, hypoplastic right heart syndrome, double-inlet ventricle and other abnormalities regarding the pumping ability of the heart. Completion of the operation results in the flow of systemic venous blood to the lungs without passing through a right ventricle.

[0004] Typically, Fontan procedures are completed in two stages. The first stage involves redirecting blood flow from the upper body through the superior vena cava so that the superior vena cava carries blood to the pulmonary arteries instead of the right atrium of the heart. During this stage, venous blood from the inferior vena cava continues to carry blood from the lower body to the heart. In the second stage, blood from the inferior vena cava is redirected to the lungs through the pulmonary arteries. Following the completed procedure, blood flow through the lungs depends on the pressure in the veins, as blood is no longer pumped by the right ventricle. Creation of a Fontan circulation is palliative in nature, with good results in patients with ideal hemodynamics and substantial morbidity and mortality in those with poor hemodynamics. "Fontan patients" entering adulthood face an uncertain future.

[0005] Due to the burden placed on the venous system through completion of a Fontan procedure, a common problem subsequent to the operation is an excessive rise of central venous pressure. Namely, excessive blood pressure in the superior vena cava and the inferior vena cava. Other complications of Fontan circulation include exercise intolerance, ventricular failure, right atrium dilatation and arrhythmia, systemic and hepatic venous hypertension, portal hypertension, coagulopathy, pulmonary arteriovenous malformation, venovenous shunts, and lymphatic dysfunction (e.g., ascites, edema, effusion, protein-losing enteropathy, and plastic bronchitis). Further details regarding Fontan procedures can be found in, for example, Fredenburg, et al., The Fontan Procedure: Anatomy, Complications, and Manifestations of Failure, 31 RADIOGRAPHICS 453, (2011).

[0006] At present, patients who have undergone Fontan Procedures that fail typically have two principal options: undergo a heart transplant or a total artificial heart implantation. In most cases, Fontan patients are not ideal candidates for either of the aforementioned procedures, as such patients are at greater risk of injury as a result of major surgery, particularly open surgery. Also, a heart transplant is not ideal as a solution when the Fontan procedure has already been performed due to the altered anatomy of the superior and inferior vena cavae. Another approach involves implanting a left ventricular assist device (LVAD). However, such a device does not fully address the problem of a failed Fontan procedure. Therefore, new solutions to problems arising from Fontan procedures are desired.

BRIEF SUMMARY OF THE INVENTION

[0007] A first aspect of the present invention provides a method of medical treatment. A first step of the method desirably involves connecting a pump having an inflow port and an outflow port to a body of a subject so that the inflow port is in fluid communication with at least one of the venae

[0008] cavae and the outflow port is in fluid communication with at least one of the left or right pulmonary arteries. A second step of the method desirably involves operating the pump to carry at least some blood flow from at least one of the venae cavae into at least one of the left or right pulmonary artery.

[0009] In one embodiment of the first aspect, the patient has been subject to a Fontan procedure prior to connecting the pump so that the venae cava are in communication with the pulmonary arteries. In another embodiment, the method also includes steps of measuring a property related to blood on or in the inflow and/or outflow cannula; communicating a signal related to the property related to blood to a controller connected to the pump; and controlling the pump responsive to the signal. In yet another embodiment, the pump is operated to carry at least some blood flow. In particular, the operation of the pump may include carrying blood through an inflow cannula from the at least one of the venae cavae into the pump and carrying blood through an outflow cannula from the pump into the at least one of the left or right pulmonary arteries. In another embodiment, the outflow cannula is adapted to create at least a partial seal or obstruction so that when the outflow cannula is disposed in a vessel during operation of the pump, at least some blood outflow from the outflow cannula is prevented from being regurgitated back into a vein. In another embodiment, the vessel is sealed by actuating a balloon attached to the outflow cannula prior to operating the pump so that the balloon at least partially seals a space between an outer surface of the outflow cannula and the surrounding vessel to prevent backflow of blood into either of the vena cavae.

[0010] Another aspect of the present invention provides a method of implanting a medical treatment apparatus. The method of implantation desirably includes the following steps: making at least one percutaneous incision in a patient; simultaneously or sequentially inserting an inflow cannula through one of the at least one percutaneous incision and an outflow cannula through one of the at least one percutaneous incision such that both the inflow and outflow cannula enter a vein; advancing the inflow cannula into the superior vena cava; and advancing the outflow cannula into at least one of the right or left pulmonary artery. Typically, the inflow and outflow cannula are both connected to a pump so that during operation of the pump, at least one of the superior vena cava and inferior vena cava is in fluid communication with at least one of the right or left pulmonary artery through the pump.

[0011] In one embodiment, the patient has been subject to a Fontan procedure prior to making the at least one percutaneous incision so that the vena cava is in communication with the pulmonary arteries. The method may involve inserting a guidewire through the outflow cannula and actuating the guidewire, wherein actuation of the guidewire repositions at least one of the inflow and outflow cannula. In a variant of the above embodiment, a second guidewire is inserted through the inflow cannula so that actuation of the first guidewire positions the outflow cannula and actuation of the second guidewire repositions the inflow cannula. The inflow and outflow cannula may be inserted simultaneously through the same percutaneous incision. In a variant, an inserter sheath is placed through the percutaneous incision prior to disposing the inflow and outflow cannula simultaneously through the inserter sheath. In yet another embodiment, advancing the outflow cannula into at least one of the right or left pulmonary artery creates at least a partial seal between at least one of the left or right pulmonary artery and the outflow cannula disposed therein. A balloon connected to the outflow cannula may be actuated after advancing the outflow cannula into at least one of the right or left pulmonary artery. In this case, actuation of the balloon may cause the balloon to at least partially seal the at least one of the right or left pulmonary artery surrounding the outflow cannula.

[0012] In yet another aspect, the present invention relates to a kit for improving blood flow in a patient. The kit desirably includes a pump and an inflow and outflow cannula adapted to be connected to the pump. The inflow cannula may be adapted for placement into at least one of the superior vena cava or the inferior vena cava and the outflow cannula may be adapted for placement into at least one of the right pulmonary artery or the left pulmonary artery.

[0013] In one embodiment, the inflow cannula includes a length that is longer than a length of the outflow cannula. In another embodiment, one of the inflow and outflow cannula is entirely disposed within the other of the inflow and outflow cannula over at least a portion of the length of the inflow cannula. In yet another embodiment, the outflow cannula further comprises a first outflow cannula and a second outflow cannula. The first outflow cannula is adapted to be disposed within one of the right or left pulmonary artery and the second outflow cannula is adapted to be disposed in the other of the right or left pulmonary artery. In another embodiment, the pump is adapted for placement inside a body of the patient so that placement is either subcutaneous, sub-muscular or within the abdominal, thoracic or other body cavity.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 is a side view of a bypass apparatus in accordance with one embodiment of the invention.

[0015] FIG. 2 is a side view of the bypass apparatus shown in FIG. 1 during one stage of a procedure according to an embodiment of the invention.

[0016] FIG. 3 is a fragmentary sectional view of the bypass apparatus shown in FIG. 1.

[0017] FIG. 4 is a diagrammatic perspective view illustrating a first step of a method of implanting the bypass apparatus according to one embodiment of the invention, employing the apparatus shown in FIG. 1.

[0018] FIG. 5 is a side view illustrating another step of the method. [0019] FIG. 6 is a view similar to FIG. 5 but illustrates another step in the method.

[0020] FIG. 7A is a similar view as that shown in FIG. 5 but depicting an apparatus and method according to another embodiment

[0021] FIG. 7B is a fragmented sectional view of the inserter with cannulas disposed therein shown in FIG. 7A.

[0022] FIG. 8 is a side view of a bypass apparatus in accordance with another embodiment of the invention.

[0023] FIG. 9 is a fragmented sectional view of an inflow and outflow cannula of the bypass apparatus shown in FIG. 8.

[0024] FIG. 10 is a side view of a bypass apparatus in accordance with another embodiment of the invention.

[0025] FIG. 11 is a fragmented sectional view of an inflow and outflow cannula of the bypass apparatus shown in FIG. 10.

[0026] FIG. 12 is a side view of a bypass apparatus in accordance with another embodiment of the invention.

[0027] FIG. 13 is a side view of an inflow and outflow cannula in accordance with another embodiment of the invention.

[0028] FIG. 14 is a side view of a bypass apparatus in accordance with another embodiment of the invention.

[0029] FIG. 15 is a side view of a bypass apparatus in accordance with one embodiment of the invention.

[0030] FIG. 16 is a fragmentary sectional view of the bypass apparatus shown in FIG. 15.

[0031] Throughout the drawings, the same reference numerals and characters, unless otherwise stated, are used to denote like features, elements, components, or portions of the illustrated embodiments. Moreover, while the present disclosure will now be described in detail with reference to the figures, it is done so in connection with the illustrative embodiments and is not limited by the particular embodiments illustrated in the figures.

DETAILED DESCRIPTION

[0032] The various apparatuses, kits and methods of the present invention are intended for improvement of blood flow and/or to reduce venous pressure in a patient. One particularly beneficial application of the embodiments described herein is in post-operative Fontan patients to direct and accelerate blood from the veins to the lungs through the pulmonary arteries.

[0033] The term "patient" as used throughout is interchangeable with the term "subject" as used throughout and is intended to refer to the person who is the recipient of the apparatus of the invention.

[0034] A bypass apparatus 10 according to a first embodiment of the invention is shown in

FIG. 1 and can be used to improve blood flow into the lungs following Fontan procedures as described below. The apparatus includes a blood pump 1. The pump can be of any type known in the art. In some variants, and as shown in FIG. 1, the blood pump 1 includes an inflow port 3 and outflow port 5. In others, the pump may simply include an inlet and an outlet. A suitable blood pump for the methods described herein is an implantable rotary blood pump, for example, certain rotary blood pumps are disclosed in U.S. Patent Nos. 6,234,772, 7,699,586, 8,157,720, 8,545,380, 8,512,012 and 8,882,477 which are expressly incorporated by reference herein. The use of other types of implantable pumps may also be advantageous in the present invention. The pump 1 is configured so that it can be disposed internal to the patient in a cavity within the body. One non-limiting example of placement is extrathoracic, or outside the rib cage. Placement can be either subcutaneous or sub-muscular. Other examples of pump placement include within a body cavity such as the abdominal cavity or the thoracic cavity. Placement in other body cavities is also contemplated. Alternatively, the pump 1 can be placed extracorporeally. The pump 1 can also include features so that monitoring devices and other equipment may be affixed to the pump 1. The position of the inflow port 3 and outflow port 5 on the pump 1 is as shown in FIG. 1. Alternatively, ports 3, 5 can be located at any suitable position on the pump 1 to suit the anatomy of the patient.

[0035] The apparatus 10 also includes an inflow cannula 9 and an outflow cannula 11, as shown in FIGS. 1, 2 and 3. The combined inflow and outflow cannulas 9, 11 are suited for insertion into a blood vessel and also for advancement through the vessel. As shown in FIG. 1, the inflow cannula 9 and the outflow cannula 11 are arranged in a side -by-side configuration and are attached to one another along part of the length of each cannula. In this configuration portions at the extreme distal end 21, 22 are separated so that each cannula can extend into a separate vessel.

[0036] In the configuration shown, the inflow cannula 9 and the outflow cannula 11 are secured to each other through a temporary attachment. The temporary attachment is configured and manufactured in such a way to facilitate the peeling of the inflow cannula 9 from the outflow cannula 11. Some examples of this configuration include scoring of the interface between the two cannulas, or manufacturing the cannulas with a thinner layer of material at the border between the cannulas so that it is easy to peel them apart.

[0037] The relative positioning of the inflow cannula 9 and outflow cannula 11, and in particular, the inclusion of properties in the cannulas so that one can be peeled from the another, aids the clinician in placement. It also facilitates placement of both the inflow cannula 9 and outflow cannula 11 in a single operative procedure through a single entry point or incision. As described in greater detail below, the clinician is able to separate or peel the two cannulas to enable them to be separated and placed in separate vessels. The inflow cannula 9 as shown in FIGS. 2-3 is configured to be placed in the inferior vena cava and the outflow cannula 11 is configured to be placed in one or both of the pulmonary arteries.

[0038] The cannulas can be made of a biocompatible material such as a biocompatible polymer with or without reinforcement or a biocompatible metal such as nitinol. Cannula 9 has an inner lumen 32A for transporting blood from the patient whereas cannula 11 has an inner lumen 32B. In this embodiment, the inflow and outflow cannula are of equal diameter and thickness, as shown in FIG. 3, where both the inflow and outflow cannula 9, 11 have inner diameters of about 5 mm. Also in FIG. 3, the outer diameter of each cannula is identified as 6 mm, thus making the thickness of each cannula wall 13 approximately 0.5 mm. Alternatively, the cannulas can be of a larger or smaller diameter, or of varying diameter and thickness, depending on the patient and specific requirements dictated by the patient's anatomy. Nonetheless, the cannulas should be of a diameter small enough so that natural flow through the vasculature is not completely blocked.

[0039] As shown in FIG. 2, the inflow cannula 9 is longer than the outflow cannula 11. In other embodiments, the outflow cannula 11 can have the same or greater length than the inflow cannula 9. Again with reference to FIG. 2, the inflow cannula 9 includes openings 39 that are distributed at roughly equal intervals from the distal end 22 up to approximately 10 cm from the distal end 22. Openings 39 extend from the exterior surface of the inflow cannula 9 to the lumen 32A (FIG. 3). The outflow cannula 11 as shown includes a balloon 15 disposed adjacent the distal end 21 of the outflow cannula 11 and an inflation lumen 17. As best seen in FIGS. 2 and 3, the inflation lumen 17 extends from a proximal end 19 of the outflow cannula 11 to the balloon 15 and communicates with balloon 15. FIG. 3 in particular shows that the inflation lumen 17 is located within the wall 13 of the outflow cannula. In a variant, the inflation lumen can be placed outside of the wall or inside the wall 13. The balloon 15 is configured to be actuated between a collapsed and inflated or expanded condition. For example, in FIG. 2, the balloon 15 is in a collapsed condition as the outflow cannula 11 is advanced through the subclavian vein 50 and the superior vena cava 52. In contrast, FIG. 6 shows the balloon 15 in an inflated condition where the outflow cannula 11 is in a desired position in the right pulmonary artery 56.

[0040] The proximal ends 19, 20 of the inflow and outflow cannulas are configured with placement adapters, 23 and 25, respectively (FIG. 2), to facilitate placement of the cannulas in the patient. In the embodiment shown, the placement adapter 25 at the proximal end 19 of the outflow cannula 11 has a " Y" configuration. In this configuration, the proximal end of the y-shaped placement adapter 25 has two openings. An opening in the first fitting 27 communicates with the inner lumen 32B of the outflow cannula 11 and is configured to receive a guidewire 12B, or the like. The opening in the second fitting 29 communicates with inflation lumen 17 and is configured to receive a syringe (not shown) to inflate the balloon 15 via the inflation lumen 17. The placement adapter 23 at the proximal end 20 of the inflow cannula 9 has a fitting 24 with an opening and is configured to receive a guidewire 12A. Each placement adapter 23, 25 as shown is coupled to the proximal end of the respective cannulas 19, 20 so that the adapters are in communication with the lumens 32A, 32B of the cannulas. The placement adapters 23, 25 are configured to receive a guidewire 12A, 12B, or the like, to aid in advancement and placement of the inflow and outflow cannulas 9, 11 in the patient. To connect the inflow and outflow cannulas 9, 11 to the pump 1, the placement adapters 23, 25 include fittings 24, 27 as shown in FIG. 2 configured to connect and create seals with the inlet port 3 and outlet port 5. The adapters are also configured to be connectable to the type of pump being deployed in the procedure. [0041] The apparatus according to this embodiment includes two guidewires 12A, 12B, as shown in FIGS. 2-5. The guidewires 12A, 12B are configured so that a cannula configured for placement into the vasculature can be placed over a guidewire or otherwise around it. The guidewires 12A, 12B are coated with or otherwise made of biocompatible materials and are otherwise safe for use inside the body. Each guidewire 12A, 12B also includes flexible properties to the extent necessary to bend within the vasculature as it is advanced. The guidewires 12 A, 12B may be steerable per se and may incorporate conventional features normally used in guidewires.

[0042] It is contemplated that the elements of the above apparatus can also be included in any combination of elements as a kit. For example, a kit in one embodiment of the present invention can include a pump, an inflow cannula and an outflow cannula. In some embodiments, the kit can also include additional devices, accessories and/or tools. For example, the kit can include guidewires, introducer needles, vascular dilators, introducer sheaths, syringes, stopcocks, scalpels and/or other devices, accessories and tools used during surgical procedures.

[0043] A method according to a further embodiment of the invention can be practiced using the bypass apparatus 10 on a patient who has previously had a complete Fontan procedure. As shown in FIGS. 5 and 6, following a Fontan procedure, the superior 52 and inferior vena cava 54 have each been anastamosed to a pulmonary artery 56, 58. Without further mechanical assistance, this anatomical configuration allows for blood to flow from the superior and inferior vena cava, directly to the right pulmonary artery, left pulmonary artery, or both. The completion of a Fontan procedure bypasses the right side of a patient' s heart through a redirection of blood from the venae cavae directly into at least one of the pulmonary arteries. Depending on the patient and the type of Fontan procedure performed, the venae cavae may still remain connected to the right ventricle and some blood flow may continue to be carried from the venae cavae into the right side of the heart after the procedure.

[0044] The method according to this embodiment commences with the formation of the percutaneous incision 51 in a patient as shown in FIG. 4. Two guidewires 12 A, 12B are then inserted through the percutaneous incision 51 and into the superior vena cava 52. As shown in FIG. 5, one guidewire 12B is advanced so that it is directed into the right pulmonary artery 56. Similarly, another guidewire 12A is advanced so that it is directed into the superior vena cava 52 toward the inferior vena cava 54.

[0045] The inflow and outflow cannulas 9, 11 are prepared for insertion into the patient. As depicted in FIGS. 4-6, a clinician determines how much of the distal end 21, 22 of each cannula should be separated prior to placement of the inflow 9 and outflow cannula 11. This determination is made, in part, based on the radiography and locations of the branches of the relevant blood vessels. The inflow cannula 9 and outflow cannula 11 may be separated such that each cannula is long enough to reside in its respective destination vessels such as the inferior vena cava and the right pulmonary artery. In FIGS. 5 and 6, separation on a portion of the distal ends of the inflow and outflow cannula is visible. The separation determination is made prior to insertion of a combined inflow and outflow cannula. Then, as shown in FIG. 4, the clinician inserts the distal ends 21, 22 of the cannulas over the guidewires 12A, 12B and through the percutaneous incision 51, which provides surgical access to the subclavian vein 50. With the separation of each cannula established, the inflow and outflow cannula 9, 11 are simultaneously placed over respective guidewires 12A, 12B, and into the superior vena cava 52 via the subclavian vein 50 and/or brachiocephalic vein, as shown in FIGS. 4 and 5. Simultaneous insertion of the inflow 9 and outflow cannula 11, which are attached to each other, facilitates insertion and minimizes the risk of damage to the vasculature. Once the junction of the superior vena cava (or inferior vena cava), and right pulmonary artery is reached, the clinician uses the guidewire 12B from the outflow cannula 11 to guide the outflow cannula 11 away from the inflow cannula 9, into the pulmonary artery, as shown in FIGS. 5 and 6. In other words, the clinician actuates the guidewires. The clinician may be assisted by the placement adapters 23, 25 and the respective fittings 24, 27 through which the guidewires 12A, 12B pass at the proximal ends 19, 20 of the cannulas. The inflow cannula 9 will be advanced to and ultimately reside in the inferior vena cava 54, while the outflow cannula 11 will reside in the right pulmonary artery 56, as shown in FIG. 6, and/or the left pulmonary artery 58. Once the outflow cannula 11 is in the desired location, the balloon 15 can be inflated through actuation of an end of an inflation lumen 17 at the second fitting 29 adjacent to the proximal end 19 of the outflow cannula 11. In one example, actuation can be accomplished with a syringe (not shown) filled with saline or another acceptable liquid or gas. The syringe is inserted into an opening in the second fitting 29 of placement adapter 25 by a clinician (see FIG. 2) and actuated to inflate the balloon 15. The inflated balloon 15 secures the outflow cannula 11 in place and prevents backflow of fluid.

[0046] Once the inflow and outflow cannula 9, 11 are positioned as intended and the balloon

15 is inflated, the clinician secures the fitting 24 adjacent to the inflow cannula 9 to the inflow port 3 on the pump 1 and the first fitting 27 adjacent to the outflow cannula 11 to the outflow port 5 on the pump 1.

To complete the procedure, the connected pump 1 is placed in a subcutaneous pocket 53 under the skin

52 of the patient (FIG. 6), for example, at or near the patient's rib cage. Placement can also be at any extrathoracic location or in other locations in the body depending on the physical characteristics of the patient. Once the inflow and outflow cannulas are fully secured to the pump, the venae cavae are in fluid communication with the right pulmonary artery via the inflow 3 and outflow 5 ports of the pump.

[0047] With the bypass apparatus 10 fully inserted, the pump 1 is activated. Blood is pumped through the blood flow lumen 32A in the inflow cannula 9 from the inferior vena cava 54 and/or the superior vena cava 52 into the pump 1 entering the inflow cannula 9 through openings 39, as shown in

FIG. 6. A longer distribution of openings 39 ensures that the inflow is distributed along the length of the vena cava so that no single location has too much inflow. This helps to prevent the vena cava from collapsing inward occluding blood flow entirely. Put another way, the distribution of openings on the inflow cannula optimizes suction inflow without causing suction of a magnitude that would cause the walls of the venae cavae to be drawn towards the inflow cannula. This maintains natural blood flow through the venae cavae. Blood in the pump 1 is then returned, via the blood flow lumen 32B in the outflow cannula 11, into the one or both of the pulmonary arteries 56, 58. As shown in FIG. 6, blood is returned to the right pulmonary artery 56. The balloon 15 included on the outflow cannula 11 prevents outflow blood from doubling back along the exterior of the outflow cannula 11 and into the inferior 54 and/or superior vena cava 52. In a variant, the outflow cannula can include two or more balloons. The blood flow rate through the bypass apparatus 10 should be sufficient so that it provides a desired pressure in the venae cavae and the right and/or left pulmonary arteries. For example, in some patients, a flow rate of about 2-3 liters per minute when pumping blood into a single pulmonary artery is sufficient. Of course, the exact flow rate necessary for successful operation of the pump will vary based on factors such as the patient's physical characteristics. Accordingly, the flow rate may vary substantially from that indicated in the example above. The flow rate desirably is controlled so as to prevent the development of a pulmonary edema or pulmonary hypertension. Also, the pump is desirably controlled so that mean pressure in the vena cava is maintained within a desired range to prevent development of conditions associated with excessively high or excessively low pressure in the vena cava as discussed above. The desired pressures may be based on pressures that a patient normally experiences over an extended duration, such as a period of several weeks. Of course, the pressure normally experienced by a patient will vary by patient. . Through operation of the pump 1 as described above, blood bypasses the damaged or missing portions of the patient's right heart. Insertion and operation of the bypass apparatus 10 can be in response to, for example, a failed Fontan procedure, as a supplemental procedure in conjunction with a Fontan procedure or as a temporary measure following a Fontan procedure.

[0048] As described above, blood flow in a Fontan circulation following a Fontan procedure may eventually lead to complications such as excessive central venous pressure, and for at least those reasons, the methods herein are particularly applicable to patients suffering from a failed or a failing Fontan procedure. The methods provide an additional bypass that relieves the excessive central venous pressure in the venae cavae. Namely, the inflow cannula 9 serves to divert blood from the venous system by way of the pump 1, while the outflow cannula 11 serves to deliver blood back to the pulmonary arterial system of the patient, while bypassing the right atrium and/or ventricle. Other advantages of the method include an increase in blood flow to the lungs, improved oxygen uptake into the body, a reduction in protein wasting, and minimization of other serious side effects related to a failed Fontan procedure. The addition of a pump to provide improved blood flow to the pulmonary arteries of Fontan patients is in itself an improvement over existing techniques. Furthermore, in the method described, both the inflow cannula 9 and outflow cannula 11 can be placed through the same entry point, i.e. , the percutaneous incision 51. By performing the procedure through a single entry point, risk of injury to a patient that has previously undergone a Fontan procedure is reduced. As stated above, Fontan patients are likely to fare better when a minimally invasive procedure is used, as such patients are susceptible to injury as a result of open surgery to replace the heart or revision surgery to repair an existing Fontan procedure.

[0049] The apparatus and method described above can be varied in many respects. In one embodiment, the bypass apparatus 10 can include an inserter sheath 14, as shown in FIGS. 7A and 7B.

The inserter sheath 14 is configured for placement internally within the body and in particular, within the vasculature. In one example, the inserter sheath is a peel-away sheath that is removable from the body following the implantation procedure. As shown in FIG. 7B, the inserter sheath 14 is a tubular structure with a lumen 34 sized to permit inserter of at least the inflow and outflow cannula 9, 11 therethrough. It is coated with or otherwise made of biocompatible materials. The inserter sheath 14 is used to assist in the inserter of the inflow and outflow cannulas. After a percutaneous incision 51 is made, the inserter sheath 14 can be inserted through the incision 51 and advanced to the location joining the venae cavae 52, 54 with the pulmonary arteries 56, 58. The inflow and outflow cannulas 9, 11 are then disposed in the lumen 34 of the inserter sheath (FIG. 7B) and advanced into the vasculature, directed by the alignment of inserter sheath 14. In some embodiments, the structure of the cannulas and elements connecting the cannulas to the pump can be varied. For example, structures distinguishable from a cannula but having a lumen may also serve the function of the cannula 9, 11 and could also be included as part of the bypass apparatus. In another example, the first and second cannula may be slidably connected to one another, promoting ease of use. Other mechanisms for temporary attachment between cannulas include a soluble polymer that would eventually cause the cannulas to separate. More broadly, any materials, cannula surface shape or other treatment that allows the cannulas to be separated, split or detached can be used. Alternatively or additionally, a portion of the side -by-side arrangement can be fully and permanently secured provided that free ends 21, 22 of the cannulas are free to move with respect to each other so that each is capable of entering separate vessels. In some embodiments, the placement adapters are removably connected to the cannulas. While connected, the placement adapters enclose pump adapters on the cannulas configured to engage with an inlet and outlet of the pump. To secure the cannulas to the pump, the placement adapters are decoupled from the cannulas, and the pump adapters are secured to the inlet and outlet of the pump. Where one or more cannulas include a balloon in communication with a proximal end of the cannula via an inflation lumen, the pump adapter is configured to close a proximal end of the inflation lumen upon decoupling of the placement adapter. The pump adapters may be configured to be connectable with any type of pump being deployed in the procedure. The pump adapters allow for quick attachment between the cannulas 9, 11 and the pump 1. Placement adapters varying from those shown in FIG. 2 are also contemplated. Namely, it is contemplated that other connector devices that are configured for releasable or permanent connection to the cannula at the proximal end 19, 20 of each cannula may be included as part of the bypass apparatus used in the method. Such connector devices can be configured for placement of guidewire and/or devices (e.g., syringe) to apply fluid pressure or other forms of actuation into a lumen of the cannula.

[0050] In other embodiments, the steps for inserting the bypass apparatus can vary from the above embodiments. For example, the insertion procedure may be conducted with a single guidewire or in other cases, with three or more guidewires. In some embodiments, the method may be supplemented with the placement of valves and/or occluders in one or more vessels, or the balloon on the outflow cannula may be replaced with another device to seal a surrounding vessel. In addition, the outflow cannula of the bypass apparatus may have a diameter so that when it is disposed in a vessel, such as a right pulmonary artery, it creates a partial or full seal of the vessel. The outflow cannula can also create an obstruction in the vessel. Thus, at least some regurgitation or backflow of blood from the vessel into the venous system is prevented due to the seal and/or obstruction. In some embodiments, the approach to insertion of the cannulas can be varied. For example, the cannulas can be placed sequentially and/or into separate percutaneous incisions in the event that the cannulas are separated from one another prior to insertion into the patient. One or both cannulas can be inserted into one of the right internal jugular vein, right external jugular vein, right subclavian vein, right axillary vein or the right brachiocephalic vein. From any of these veins, the cannula can be advanced into the superior vena cava. In other examples, one or both of the cannulas can be inserted into one of the left internal jugular vein, left external jugular vein, left subclavian vein, left axillary vein or left brachiocephalic vein. Similarly, from any of these veins, the cannula can be advanced in the superior vena cava. In further examples, both cannulas can be inserted into any one of the above referenced veins at different locations along the length of the vein. In some of the above examples, the distal end 22 of the inflow cannula 9 is only advanced into the superior vena cava 52 and does not extend into the inferior vena cava. In yet another example, the bypass apparatus is inserted into a percutaneous incision and advanced into the inferior vena cava from the incision without initially advancing through the superior vena cava. When the bypass apparatus is advanced into the inferior vena cava from the lower half of the venous system, it can initially be inserted into the right or left femoral vein and from there, advanced into the inferior vena cava. In other examples, the methods of insertion described herein can be used and or modified for application in the vasculature of a patient that has not undergone a Fontan procedure. In such cases, a vessel pathway to the pulmonary arteries must remain relatively unobstructed and accessible for optimal application of the methods described herein. In still further embodiments, the cannulas 9, 11 are inserted so that proximal ends of the cannulas extend through and out of the skin of the patient. From the exposed cannulas, the pump is secured and positioned extracorporeally. Extracorporeal placement is particularly well suited when the intended use of the bypass apparatus is temporary. It also has the advantage of being more easily adapted to connect with monitoring equipment.

[0051] In any one of the above embodiments, operation of the bypass apparatus 10 can be supplemented with devices (FIGS. 15-16) and analysis equipment connected to or integrated with the pump 1 configured to measure properties relating to blood such as pressure or flow rate in one or more of the cannula, in the vasculature such as in the pulmonary artery or vena cava, or the like. Devices for measurement of properties of blood can be sensors and analysis equipment can be a controller connected to the pump. Where sensors and a controller are included, the sensors are configured to communicate with the controller connected to the pump. The sensors can be configured to monitor pressure and flow rate in vessels such as the venae cavae and pulmonary arteries, among other measurable properties. Measurement can be at one or more locations on the length of the inflow and outflow cannula. The sensors are further configured to transmit signals to the controller based on measurements such as those described above. Transmission of signals can be via a lumen within a wall of the cannula or optical cable and/or electrical conductor inside or outside the wall of the cannula. Specific examples of sensors and transmission mechanisms include a micro-manometer pressure sensor, fluid inside a lumen and a fiber optic pressure sensor. Also, fluid in a separate lumen may transmit pressure from a tip of the cannula to a sensor outside the body. The controller is configured to monitor and analyze the received signals. The controller can monitor various forms of energy received as a signal. Through analysis of the signals, the controller can regulate the activity of the bypass apparatus. For example, pressure in the venae cavae can be monitored (i.e., estimated in real time) and regulated by the controller. In one example depicted in FIGS. 15-16, measurement sensors 672A, 672B are connected to a controller 670 via pump 601. In the bypass apparatus 610 depicted, the sensors 672A, 672B communicate with the controller 670 via optical or electrical conductors 671A, 671B disposed in walls 613 of respective inflow and outflow cannulas 609, 611, as shown in FIG. 16. The devices and analysis equipment described are also contemplated as being compatible with either an extracorporeal pump or an internally disposed pump. In a further variant, sensors can communicate with the controller via wireless communication.

[0052] Additional embodiments are shown in FIGS. 8-14. In the depiction of the embodiments shown in the figures, the bypass apparatus is in the inserted position. Unless otherwise described, the bypass apparatus of the embodiments depicted in FIGS. 8-14 generally operates in a similar manner to the bypass apparatus described above. In one embodiment, a bypass apparatus 110 can include an inflow 109 and outflow cannula 111 entirely separate from one another, as shown in FIGS. 8 and 9. The structure may otherwise be the same as described in the above embodiments. A sectional view of the inflow and outflow cannula 9, 11 through the subclavian vein 150 is depicted in FIG. 9. In an embodiment of a method of insertion employing bypass apparatus 110, both the inflow cannula 109 and the outflow cannula 111 can be inserted into a single percutaneous incision simultaneously or one cannula can be inserted before the other. In some variants, the inflow cannula 109 can be inserted into a first percutaneous incision while the outflow cannula 111 can be inserted into a second percutaneous incision. Where two percutaneous incisions are made, the cannulas 109, 111 can be inserted simultaneously or sequentially. The method of insertion may be otherwise as described above.

[0053] In another embodiment depicted in FIGS. 10 and 11, the inflow and outflow cannulas

209, 211 are placed concentrically so that the outflow cannula 211 is entirely disposed within the inflow cannula 209 over at least a portion of the length of the inflow cannula. FIG. 11 shows a sectional view of the cannulas through the subclavian vein 250. In the same figure, delineation of the inflow lumen 232A and outflow lumen 232B is visible. In a variant, the inflow cannula 209 can be entirely disposed within the outflow cannula 211 over at least a portion of the length of the outflow cannula 211. Each cannula is sealed so that there is no fluid communication between inflow and outflow. In an embodiment of the method, the bypass apparatus 210 is inserted through a single percutaneous incision such that each cannula is inserted simultaneously, though other approaches are contemplated as within the scope of the invention.

[0054] In yet another embodiment shown in FIG. 12, the bypass apparatus 310 includes three cannulas attached to the pump 301. One cannula is an inflow cannula 309, as described in other embodiments. The other two are outflow cannulas 311A, 31 IB. As depicted in FIG. 12, each outlet cannula is sourced from a separate outlet port 305A, 305B. However, the configuration shown is not limiting and other forms of connection are also contemplated. In some variants, the outlet for the two outlet cannulas may be shared. In the implanted position of the bypass apparatus shown in FIG. 12, the outflow cannula 311 A is disposed in the right pulmonary artery 356 and the outflow cannula 311A is disposed in the left pulmonary artery 358. The outflow cannulas 311A, 31 IB are shown positioned on opposite sides of the inflow cannula 309 where all three cannulas are secured to each other. In a variant, the two outflow cannulas 311A, 31 IB may be adjacent to each other and attached to the inflow cannula 309 on one side. In other variants, only two of the three cannulas are attached. In others, all three are separate and unattached. Further variants with other arrangements of the cannulas are also contemplated, including adjustment of the position of the cannulas within the vasculature as described in the above embodiments. Of course, when any two cannulas are attached, attachment may be temporary or fixed as described above. Each outflow cannula includes a balloon 315A, 315B proximal to its distal end 321A, 321B, as shown in FIG. 12. During insertion of the bypass apparatus 310, each outflow cannula 311A, 31 IB may have a placement adapter 325 A, 325B including a first opening for a guidewire and a second opening for a syringe, as described above. As in other embodiments, a clinician may use the guidewires to aid in directing the cannulas into a desired position.

[0055] In another embodiment shown in FIG. 13, a bypass apparatus 410 includes an outflow cannula 411 A that extends from the pump 401 with a single lumen up to a divergence location 414 where the cannula 411A splits into two outflow cannulas 41 IB, 411C. The divergence location 414 can include a ring, fitting or other adapter to split the cannula 411 A. As seen in FIG. 13, downstream from the divergence location 414, the outflow cannula 41 IB extends into the right pulmonary artery 456 and the outflow cannula 411C extends into the left pulmonary artery 458. For the apparatus as shown, two guidewires (not shown) may be disposed in outflow cannula 411 A. A modified placement adapter may be used accordingly. Each outflow cannula 41 IB, 411C also includes a balloon 415B, 415C or valve towards a distal end of each cannula, as shown in FIG. 13. When in the inserted position as shown, the bypass apparatus 410 operates similarly to the three cannula bypass apparatus 310 described above.

[0056] In yet another embodiment shown in FIG. 14, a pump 501 of the bypass apparatus 510 is disposed in the vasculature. In the particular variant of the embodiment shown, an inflow cannula 509 is disposed in the superior vena cava 552 and extends to the pump 501 disposed in the right pulmonary artery 556. The inflow cannula 509 includes openings 539 and may further include a powered lead 561 attached to the inflow cannula 509, as shown. The powered lead 561 extends to a source of electrical power such as a percutaneous connection or a transcutaneous energy transfer system. Pump 501 is secured between the inflow and outflow cannulas 509, 511. One example of a pump that may be placed within the vasculature is found in US Pat. No. 8,852,072, hereby incorporated by reference in its entirety.

The outflow cannula 511 extends from the pump 501 in the direction of blood flow to a free end in the right pulmonary artery 556 and includes a balloon 515 to prevent backflow, as described in the embodiments above. Of course, other examples of bypass apparatus 510 include an arrangement where the inflow cannula 509 extends toward the inferior vena cava 554 and/or one where the pump 501 and the outflow cannula 511 are disposed in the left pulmonary artery 558 in their implanted position. Further, the pump 501 may be disposed in one or both of the venae cavae. The bypass apparatus 510 may also include two outlet cannulas, one extending into each of the right and left pulmonary arteries. For these and other structural configurations, additional features such as valves, additional balloons, or other elements may be added to enhance function and improve safety. Bypass apparatus 510 may be implanted in a manner similar to that described for the embodiments above. For example, a percutaneous incision is made in a patient, and an inserter sheath is placed therethrough. The inserter sheath is placed far enough into the vasculature so that any object placed therethrough can be directed to at least one of the pulmonary arteries. In part because the diameter of the pump is very compact, the bypass apparatus 510 can be inserted through the inserter sheath into the venous system and then into the superior venae cava 552. In operation, blood flows into the openings 539 on the inflow cannula 509, potentially assisted by the powered lead 561, and then into the pump 501, which pumps blood into at least one pulmonary artery 556, 558 through the outflow cannula 511. The balloon 515 or valve prevents backflow into the venae cavae. In variants of bypass apparatus 510, additional valves or occluders may be attached to the cannulas or otherwise placed into the vasculature to control blood flow according to the placement of the apparatus elements.

[0057] Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.