WO2020215090A1

WO2020215090A1 - Temporary shunt for post-operative atrial fibrillation

Info

Publication number: WO2020215090A1
Application number: PCT/US2020/029013
Authority: WO
Inventors: Robert C. Taft; Glen Rabito; Stanton J. Rowe; Alexander Siegel; Joseph Passman
Original assignee: NXT Biomedical
Priority date: 2019-04-18
Filing date: 2020-04-20
Publication date: 2020-10-22

Abstract

Methods and devices for creating a shunt through the septum of a heart to relieve pressure on the heart's left or right atria are disclosed for reducing the risk of post-operative atrial fibrillation. One or more shunts can be created between the right and left ventricles, right and left atriums, or both. The one or more shunts can be surgically created via a scalpel or similar piercing device, or via a catheter. The shunts can be created and held open via degradable stitches or with an implantable support device.

Description

TEMPORARY SHUNT FOR POST-OPERATIVE ATRIAL FIBRILLATION

RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application Serial No. 62/836,021 filed April 18, 2019 entitled Temporary Inter-Atrial Shunt for Post- Operative Atrial Fibrillation, which is hereby incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

[0002] Atrial fibrillation is an abnormal heart rhythm characterized by irregular and rapid beating of the atrial chambers of the heart. It often begins as short periods of abnormal beating which become longer or more continuous over time. It may also begin as other forms of arrhythmia such as atrial flutter that then transform into atrial fibrillation. This arrhythmia is associated with an increased risk of heart failure and stroke.

[0003] Atrial fibrillation occurs in about 15% to 42% of patients after cardiac surgery and roughly 10% in noncardiac surgery. Although postoperative atrial fibrillation (POAF) is believed to be self-limiting, several studies have shown that patients with this condition may have 2-4 times the risk of stroke, infection, renal or respiratory failure, cardiac arrest, cerebral complications, or need for a pacemaker. These complications can add tens of thousands of dollars in increased hospital costs, 12-24 hours of added ICU time, and 2-5 additional days in the hospital.

[0004] While several different factors may contribute to the onset of POAF, one prominent risk factor is theorized to be large volumes of fluid given intravenously to patients during and after surgery. While these fluids may initially cause edema, or swelling of tissue due to fluid retention, this fluid often is reabsorbed back into the vascular system within 2-3 days after an operation. Back in the vascular system, the fluid can create a vascular volume overload leading to increased left or right atrial pressure and left or right atrial stretching transiently until the additional volume has been removed. POAF can last weeks, and the longer it lasts the stronger the association with worsening clinical outcomes. It is this stress on the left or right atria that is thought to damage the electrical pathways of the heart, resulting in atrial fibrillation.

[0005] Therefore, a treatment addressing this post-operative vascular volume overload may help reduce the incidences of atrial fibrillation and the resulting complications and costs associated with it.

SUMMARY OF THE INVENTION

[0006] The present invention is generally directed to procedures and devices for creating a shunt through the septum of a heart to relieve pressure on the heart’s left or right atria.

[0007] In one embodiment, a shunt is created through the atrial septum between the right and left atria. The shunt can be created surgically by making an incision with a scalpel, needle, ablation device, or similar instrument. The shunt can also be created via a catheter configured to pierce, ablate, or use similar techniques to create an opening in the septum. The shunt is preferably temporary in nature lasting in the range of 2 to 30 days. Non-implantable methods of creating a shunt, such as those described above, have been shown to close over time.

[0008] In another embodiment, a shunt is created through the ventricular septum between the right and left ventricle. The shunt can be created surgically by making an incision with a scalpel, needle, ablation device, or similar instrument. The shunt can also be created via a catheter configured to pierce, ablate, or use similar techniques to create an opening in the septum. The shunt is preferably temporary in nature lasting in the range of 2 to 30 days. Non-implantable methods of creating a shunt, such as those described above, have been shown to close over time.

[0009] In another embodiment, a plurality of relatively smaller diameter shunts can be created in either the ventricular septum between the right and left ventricle, in the atrial septum between the right and left atrium, or in both locations. The plurality of shunts can be created surgically by making an incision with a scalpel, needle, ablation device, or similar instrument. The plurality of shunts can also be created via a catheter configured to pierce, ablate, or use similar techniques to create an opening in the septum.

[0010] In another embodiment, biodegradable stitches can be used to maintain a shunt in an open configuration for a desired period of time to relieve fluid pressure in the left or right atria (e.g., 1 -4 weeks). After the stitches degrade, the shunt is left to heal and close naturally.

[0011] In yet another embodiment, a shunt support device is implanted at or near the opening of the shunt to help maintain the shunt in an open position. The support device can be configured to partially or fully close the shunt after a predetermined period of time. For example, the support device can be composed of a shape memory material (e.g., Nitinol) that assumes a radially contracted shape when unconstrained. The support device can be implanted with non-degradable stitches to maintain the device around the shunt opening, and with degradable stitches to maintain the support device in a radially expanded configuration. When the degradable stitches dissolve, they no longer provide force to counteract the device’s radially inward bias which allows the device to pull the surrounding tissue inwards to partially or fully close the shunt.

[0012] In another embodiment, a tool that is already being used in the original cardiac procedure such as a retrograde cardioplegia catheter can be used to puncture the atrial or ventricular septum in order to create an atrial or ventricular shunt. A needle can be passed through the lumen of the retrograde cardioplegia catheter and across the septum. Once the needle is across the septum, then it can be exchanged for a guidewire. Alternatively, an RF ablation guidewire can be used to cross. A dilation balloon catheter or other dilation type device can be tracked over the guidewire in order to create the hole in the septum.

[0013] In another embodiment, a tool can be temporarily left in place in order to prop open the shunt during post-operative care. Once the patient is ready for discharge, then the tool can be removed and the shunt closes. For example, most patients which undergo cardiac surgery have a chest tube left in place in order to help drain excess volume that accumulates in the chest cavity as a result of the surgery. In one example, a shunt that was implanted at the time of an original surgery is designed to be normally closed, but when a chest tube is in place and positioned near the shunt from outside the heart, the shunt may be held open by magnets. When the chest tube is removed then the shunt will close. The portion of the shunt that opens and closes the shunt may be a flat disc attached to a member of the shunt structure such that the disc is larger or about the same size than the inner diameter of the shunt. The disc portion could be made of material that is attracted to magnets or may have magnets embedded in the disc itself. The member that attaches the disc to the shunt may be a shape memory alloy that can be shape-set to the closed position where the disc covers the shunt.

[0014] Alternatively, a catheter may be placed across the septum before, during or after the surgery in order to open the shunt. The catheter is left in place until the patient’s volume status was normalized and then the catheter is removed to allow for the shunt to close by way of the disc shutting the shunt or the shunt can be left to naturally heal.

[0015] In another embodiment, a specialized coronary sinus to inter-atrial catheter can be placed into the coronary sinus and crossed into the left atrium. The catheter can have a lumen for a guidewire to aid in tracking and placement. The catheter can also have a lumen that allows for communication between the left atrium and the coronary sinus, the right atrium, the IVC or SVC. In one variation the catheter has a lumen to allow for normal flow of the coronary sinus. In one variation the catheter can have a check valve to allow for one direction flow, either right to left or left to right. In one variation, the catheter can have a lumen to allow for the injection of drugs into the cardiovascular system (e.g., amiodarone) in order to help with arrythmia management. In one variation the catheter could have pacing elements to allow for arrythmia management via the catheter.

[0016] In another embodiment, a septal shunt with a unique one-way valve design can be created. This ensures that blood can only be shunted in one direction. For example if the left atrium was of concern or the physician didn’t want right atrial deoxygenated blood to flow towards the left atrial and desaturate the patient, then the valve is placed such that blood flows only from the left atrium to the right atrium. For example, the design of the shunt could be such that the physician makes a slit in the septum and then attaches a piece of surgical fabric, such as a Dacron or PTFE sheet, on the side of the septum in which it is desired for the blood to flow. When attaching the fabric, the full perimeter of the fabric is not fully secured. The areas which are not secured create intentional leak paths in which the blood flow passes and thereby shunts from one chamber to the other.

[0017] In another embodiment, an arterial line and venous line is placed into the patient. The lines are attached to a pump. The pump can direct blood flow from the venous system toward the arterial system or from the arterial system towards the venous system in order to help balance pressures in the chambers of the heart. This circuit can be left in place during the recovery period of the patient and removed when the patient is ready to be discharged.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] These and other aspects, features, and advantages of which embodiments of the invention are capable of will be apparent and elucidated from the following description of embodiments of the present invention, reference being made to the accompanying drawings, in which:

[0019] Fig. 1 illustrates a cross sectional view of an incision being made in a septum of a heart.

[0020] Fig. 2 illustrates a cross sectional view of a shunt within a septum of a heart.

[0021] Fig. 3 illustrates an enlarged view of a shunt being held open with stitches.

[0022] Fig. 4 illustrates a cross sectional view of a balloon catheter that has pierced a septum of a heart.

[0023] Fig. 5 illustrates a cross sectional view of a heart with a plurality of shunts through a septum of a heart.

[0024] Figs. 6A, 6B, 6C, and 6D illustrates a septum of a heart being pierced and sutured. [0025] Figs. 7 A and 7B illustrate example needle types used to pierce a septum of a heart.

[0026] Fig. 8 illustrates a cross sectional view of an incision being made in a septum of a heart.

[0027] Fig. 9 illustrates a cross sectional view of a shunt within a septum of a heart.

[0028] Figure 10 illustrates a cross sectional view of a balloon catheter positioned through a septum of a heart.

[0029] Figure 11 illustrates a cross sectional view of an inflated balloon catheter positioned through a septum of a heart.

[0030] Figure 12 illustrates a cross sectional view of an inflated balloon catheter expanding an opening through a septum of a heart.

[0031] Figure 13 illustrates a cross sectional view of an inflated balloon catheter that has been pulled through a septum of a heart.

[0032] Figure 14 illustrates a cross sectional view of a heart with a plurality of shunts through a septum of a heart.

[0033] Figure 15 illustrates a view of a shunt support device in an expanded configuration.

[0034] Figure 16 illustrates a view of a shunt support device in a radially compressed configuration.

[0035] Figure 17 illustrates a view of a shunt with a patch or valve that allows blood to flow in only one direction.

[0036] Figure 18 illustrates a view of a patch that allows blood to flow in only one direction.

[0037] Figure 19 illustrates a view of a patch that allows blood to flow in only one direction. [0038] Figure 20 illustrates a shunt device for implanting in a puncture or incision.

[0039] Figures 21 A and 21 B illustrate a shunt device for implanting in a puncture or incision.

[0040] Figure 22 illustrates a shunt device for implanting in a puncture or incision.

[0041] Figures 23A and 23B illustrate a valve mechanism for a shunt device.

[0042] Figures 24A and 24B illustrate a valve mechanism for a shunt device.

[0043] Figure 25 illustrates a device with a plurality of needles for creating a plurality of small shunts within a heart.

[0044] Figure 26 illustrates a cardioplegia catheter that is further used to create a shunt within a heart.

[0045] Figure 27 illustrates a magnified view of a cardioplegia catheter used for creating a shunt in a heart.

[0046] Figure 28 illustrates a stent device with a magnetically controlled valve flap.

[0047] Figure 29 illustrates a catheter with drainage ports for allowing blood flow between various locations of the heart.

[0048] Figure 30 illustrates one lumen embodiment of the catheter of Figure 29.

[0049] Figure 31 illustrates one lumen embodiment of the catheter of Figure 29.

[0050] Figure 32 illustrates one lumen embodiment of the catheter of Figure 29.

[0051] Figure 33 illustrates a pump system and pressure monitoring device connected to the catheter of Figure 29.

[0052] Figure 34 illustrates a method of creating a shunt between a coronary sinus and a left atrium.

[0053] Figure 34 illustrates a shunt between a coronary sinus and a left atrium. DESCRIPTION OF EMBODIMENTS

[0054] Specific embodiments of the invention will now be described with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like numbers refer to like elements.

[0055] The present invention is generally directed to treatment methods and devices for reducing post-operative left or right atrial pressure for a temporary period of time (e.g., 1 -4 weeks post-operation). As will be described in more detail below, this treatment is directed to creating one or more shunts within a patient’s heart to reduce the left or right atrial pressure. For example, the shunts can be created between the left and right atriums or the left and right ventricles, either surgically or via interventional techniques. After the desired treatment period, the one or more shunts can be closed to restore the patient’s normal heart pumping functions.

[0056] Figures 1 -3 illustrate a first method of treating post-operative atrial fibrillation (POAF) by surgically creating a shunt 20 through the ventricular septum 13 of a septum between a right ventricle 12 and a left ventricle 14 in a patient’s heart 10. The shunt 20 can be created during the initial surgical procedure (e.g., cardiac surgery), although a second, later procedure is also possible.

[0057] The physician first creates one or more incisions in the ventricular septum 13 to create a passage between both ventricles 12, 14, as seen in Figure 1 . For example, the physician may create a single linear incision or may create a first incision and a second incision that is perpendicular to the first (i.e. , an“X” shape). These incisions can be created via a scalpel 30, an ablative cutting device, a dilation device, or similar instruments.

[0058] Since the shunt 20 may only be needed for a short time to reduce pressure within the left or right atria (e.g., 1 -4 weeks), the incision may be left without further treatment or devices to heal naturally, as seen in Figure 2. Alternately, biodegradable stitches can be used to hold open the shunt 20 for a desired time. Figure 3 illustrates one specific configuration of a single incision with stitches 22 that have been placed on each longitudinal side of the incision to help stretch it open and increase its width. Alternatively, the shunt opening can be propped open with a bioabsorbable stent or scaffolding structure. The stiches 22 or stent structure can be composed of polyglycolic acid, polylactic acid, polydioxanone, caprolactone, processed collagen, silk, or similar biodegradable materials so that they dissolve after a predetermined period of time, allowing the shunt 20 to heal and close. For example, if the physician determined that the stiches 22 should dissolve after about 2 weeks, stitches 22 with that rate of reabsorption can be used.

[0059] The following are examples of both absorbable and nonabsorbable stitches that can be used according to any of the embodiments of the present invention. Chromic Gut (absorbable in 2-3 weeks), Fast Absorbing Gut (absorbable in 5-7 days), Poliglecaprone 25 (Monocryl, absorbable in 2 weeks), Polyglactin 910 (Vicryl, absorbable to 25% at 4 weeks), Polyglactin 910 (Vicryl Rapide, absorbable in 2 weeks), Polydiaxonone (PDS, absorbable to 50% at 4 weeks), Nylon (Dermalon or Ethilon, nonabsorbable), and Polypropelene (Prolene, nonabsorbable).

[0060] The size of a single shunt 20 through the ventricular septum 13 or atrial 17 septum in any of the embodiments of the present invention may vary based on several factors, such as but not limited to the patients baseline or expected BMI, CO, LAP, RAP, mPAP, EDLVP, EDRVP. The shunt size should generally be large enough to divert enough volume to reduce pressure within the left and right atria, but not too large that there is too much shunted flow causing a clinically significant decrease in forward cardiac output. This is typically captured in the Qp:Qs metric which measures pulmonary flow relative to system flow. Qp:Qs should typically remain below 1.5 (i.e. no more that 50% of flow is shunted). For example, the single shunt 20 may have a diameter within a range of 2-10 mm.

[0061] In some situations, it may be desirable to create the shunt 20 via a transcatheter procedure. For example, Figure 4 illustrates a balloon catheter 31 that is advanced into the right ventricle 12 from either the superior vena cava or the inferior vena cava. The catheter 31 may include a distal tip capable of piercing the ventricular septum 13 or a separate puncturing catheter can be used first. The catheter 31 is positioned through the ventricular septum 13 so that a balloon 33 on the catheter 31 is located within the opening. Next, the balloon 33 is inflated to increase the size of the opening to a desired diameter. The balloon 33 is then deflated and the catheter 31 withdrawn from the heart 10, leaving the passage of the shunt 20 connecting the two ventricles 12, 14. As previously discussed, the shunt 20 may be left to naturally heal and close, or the tissue can be artificially held open for a predetermined amount of time by delivering bioabsorbable/dissolvable stitches or staples to the shunt 20 surgically or via a second catheter.

[0062] According to another method of the present invention, a plurality of smaller shunts can be created in the ventricular septum 13. The smaller shunts may heal quicker than a single, larger shunt while providing a similar volume of blood to pass through relative to a larger shunt. For example, Figure 5 illustrates a plurality of smaller shunts 24 that pass through the ventricular septum 13. In one example, the total area of all of the plurality of shunts is equal to a single shunt with an area of about 2-10 mm. In another example, 10-15 shunts can be created with a size of about 2 mm each. In another example, 5-10 shunts can be created with a size of about 3 mm each.

[0063] If the operative procedure initially performed by the physician allows for direct access to the heart 10, the physician can use a needle 26 to pierce the ventricular septum 13, as seen in Figures 6A and 6B. For example, hollow tip coring needles such as a Fluber point needle 26A or a standard point needle 26B can be used (Figs. 7A and 7B). Hollow tip needles can be pressed into the septum to core or remove a portion of tissue, leaving a passage through the septum.

[0064] Alternately, a multi-needle tool 120, as seen in Figure 25, may be used to create a plurality of passages/shunts at the same time. In one embodiment, the tool 120 is a hand-held surgical device having a plurality of needles 126 that extend from an inner portion of the device 120. The device 120 may also include an outer sheath 122 that can cover the needles 126 in one position and be slid back to expose the needles 126 in a second position. Optionally, the sheath 122 can be distally biased to cover the needles 126, such that pushing the distal end of the device 120 against tissues pushes against the bias of the sheath 122, allowing the needles to puncture the target location of the septum. Needles 126 can be 5mm - 20mm long for use with the atrial septum 17 and 10mm - 30mm long for use with the ventricular septum 13.

[0065] Alternately, the device 120 can be a catheter with an inner catheter portion 124 and an outer catheter sheath 122. Generally, such a catheter device functions similar to the prior embodiment, but may require additional catheter features, such as a guidewire lumen.

[0066] As in the prior-discussed methods, each of the plurality of shunts 24 can be left solely as punctures in the ventricular septum 13, without further treatment, to heal naturally over several days or weeks, or can include bioabsorbable or dissolvable stitches 28 or staples that help maintain the shunt in an open position for a period of time. When stitches are used, a fewer number of stitches are preferred (e.g. , 1 -2 stitches), since this may provide more predictable performance and rate of absorption.

[0067] One or more shunts can also be created through the atrial septum 17 to bridge the right atrium 16 with the left atrium 18. For example, Figure 8 illustrates that a scalpel 30 can be used by the physician to make one or more incisions in the atrial septum 17. This incision can be performed during an initial surgery (e.g., cardiac surgery) or during a later surgical procedure to create the shunt 32 (Fig. 9). This process is generally similar to methods of creating the ventricular shunt 20 in Figures 1 and 2, and similar shunt size, stitch considerations, and other previously discussed aspects are also applicable here.

[0068] The incision can be created in a number of different ways, such as those discussed with prior embodiments. For example, the physician may create a single incision or two perpendicular incisions. Additionally, the physician may allow the incision/shunt 32 to heal naturally or add stitches or stent structures to help hold open the incision/shunt 32 for a period of time.

[0069] Figures 10-13 illustrate an interventional procedure for creating a shunt 32. A guidewire is positioned through the inferior vena cava or superior vena cava to a location near the atrial septum 17. The atrial septum 17 is then punctured. This can be accomplished by tracking a specialized puncturing catheter with a sharp distal tip or the balloon catheter 40 may include a sharp tip or RF tip suitable for creating a puncture. As seen in Figure 10, once the puncture is created, the balloon catheter 40 is advanced through the atrial septum 17 and into the left atrium 18. The balloon 42 of the catheter 40 is then inflated as seen in Figure 1 1 .

[0070] In Figure 12, the balloon 42 is pulled through the puncture in the upper portion 17 of the septum to increase its size. Alternately, the balloon 42 can be inflated when positioned within the puncture. Finally, the balloon 42 is pulled completely through the puncture, as seen in Figure 13, leaving an enlarged opening to the shunt 32. Alternatively, the balloon can be deflated while still inside the atrial septum and removed.

[0071] In Figure 14, similar to Figure 5, a plurality of shunts 33 can be created in the atrial septum 17. This plurality of shunts 33 can be created surgically with a scalpel 30, dilator or other specialized surgical tools during an initial procedure (e.g., cardiac surgery) by making a plurality of incisions in the atrial septum 17. These surgical incisions can be created via a single incision or multiple overlapping incisions (e.g., an X pattern). Optionally, biodegradable or dissolvable stitches can be used on each shunt to maintain them in an open position for a desired period of time.

[0072] Alternately, the plurality of shunts 33 can be created with a catheter or surgical tool by advancing a catheter or tool with a sharpened tip and piercing the atrial septum 17 at multiple locations. Optionally, a second catheter or tool capable of stitching or stapling can be used to hold open each shunt for a desired period of time.

[0073] Shunts may heal at different rates depending on different patient specific factors such as age, overall health, and condition of the patient’s heart. In some circumstances, it may be desirable to have greater control over when a shunt closes so that additional complications from the shunt are avoided.

[0074] One approach to determine the shunt closure time is to implant a shunt support device that initially maintains the shunt in an open position but later closes the shunt after a predetermined period of time. For example, Figures 15 and 16 illustrate a shunt support device 100 that is fixed around a shunt 20 to maintain it in its open position (Fig. 15) and later moves the tissue around the shunt 20 together to a closed positioned (Fig. 16).

[0075] The shunt support device 100 is implanted by first creating incisions in the desired target location of the septum (e.g., the atrial septum 17 or ventricular septum 13). In the present example, at least two perpendicular incisions are made to create four triangular flaps of tissue 21 , as seen in Figure 15.

[0076] Next, the shunt support device 100 is placed around the circumference of the shunt 20. The device 100 has four struts 102 that are connected to each other to form a square shape, similar to but larger in size than the shape of the shunt 20. Different shapes are also possible, such as a rectangle, pentagon, hexagon, or other irregular shapes.

[0077] In the present example, the device 100 is connected with both biodegradable stitches 22 and non-degradable stitches 104 to the tissue surrounding the shunt 20. The device can include a plurality of loops 102B or similar features through which the stitches 22 and 104 can be positioned through to anchor the device 100. In the present example, the biodegradable stitches 22 are positioned through loops 102B at the corners of the device 100 and non-degradable stitches 104 are positioned through loops 102B at about halfway along each strut 102, between two of the corners. The degradable stitches 104 can be further placed through the tissue flaps 21 to prevent them from interfering or blocking the shunt 20.

[0078] Generally, the shunt support device 100 is composed of a memory shape material (e.g., Nitinol) and has a heat-set shape that biases the device 100 to the radially compressed configuration of Figure 16. In the present example, each strut 102 includes two inflection points 102A that are set to bend radially inward. The inflection points 102A are each located about halfway between degradable stitch 22 and non-degradable stitch 104 so that each strut is biased to form a“W” shape. Flowever, other locations of the inflection points 102A are also possible. [0079] When the device 100 is implanted around the shunt 20 in its expanded shape, both stitches 22 and 104 maintain the device 100 in its expanded shape and therefore also maintain the shunt 20 in a fully open configuration. Over time, the degradable stitches 22 dissolve, removing radial support at the corners of the device 100 while non-degradable stitches 104 remain in place. Without the support of stitches 22, the inflection points 102A move radially inward to their heat-set configuration, forming a star-like shape seen in Figure 16. As the overall radial size of the device 100 shrinks, it pulls the tissue connected at the non-degradable stitches 104 towards each other, thereby partially or completely closing the shunt 20 within a short period of time. With the tissue in closer proximity to each other, the remaining openings of the shunt 20 can quickly heal together.

[0080] The device 100 can be implanted surgically during a procedure (e.g., a cardiac procedure). Alternately, the device can be delivered via catheter.

[0081] While the previously described device 100 relies on degradable stitches to trigger its radial contraction, other mechanisms can also be used. For example, only non-degradable stitches can be used and specific stitches can be cut and removed at a later time (e.g., via a catheter or surgical procedure).

[0082] In another example, the device 100 may be configured to transition between its expanded and radially compressed configurations at a specific temperature that is well above normal body temperature via an austenite/martensite transition. After implantation, the physician can apply heat to the device 100, such as by radiofrequency, to cause the austenite/martensite transition and thereby change the shape of the device 100.

[0083] The shunts of the present specification can also be configured to allow the flow of blood in only one direction between the atria or ventricles. For example if the left atrium 18 was of concern or the physician didn’t want right atrial deoxygenated blood to flow towards the left atrium and desaturate the patient, then a valve can be placed such that blood only flows from the left atrium 18 to the right atrium 16. [0084] Figures 17 and 18 illustrate one such design of a valve that is fixed over a shunt 32 in the atrial septum 17, pushes open with blood flow from the left atrium 18 into the right atrium 16, and pushes closed with blood flow from the right atrium 16 towards the left atrium 18. First, a shunt 32 in the atrial septum 17 (or alternately the ventricular septum 13) can be created according to any of the previously described techniques. Next, a patch or sheet 1 10 of surgical fabric or material (e.g., Dacron or PTFE) can be sutured over the shunt 32. One or more stitches 22 are preferably fixed along only one side to create a sheet 1 10 that bends open. Alternately, the stitches 22 can be positioned along two or three sides to decrease the amount of blood flow through the shunt 32.

[0085] Regarding the direction the valve opens, fixing the patch on the right atrial side, for example, prevents it from being pushed through the shunt 32 and therefore will maintain a closed position, while blood flow from the left atrial side will push the sheet 1 10 open. Different valve directions are possible based on which side of the septum the sheet 1 10 is attached to.

[0086] Figure 19 illustrates a similar valve in which stitches 22 are positioned at each corner of the sheet 1 10. The sheet 1 10 may also be more loosely positioned over the shunt 32 so that blood flow moves through the shunt 32, under the sheet 1 10, and in the direction of the arrows. In other words, blood flow in one direction pushes against and circulates around the patch 1 10.

[0087] Any of the embodiments of the present invention may further include implanting stent-like devices into an incision created surgically or by interventional techniques. Examples of such devices can be found in U.S. App. No. 16/576,704 filed September 19, 2019 and entitled Method and Technology for Creating Connections and Shunts between Vessels and Chambers of Biological structures, and in U.S. App. No. 16/785,501 filed February 7, 2020 and entitled Rivet Shunt and Method of Deployment, both of which are incorporated by reference. These devices can be composed of nondegradable materials or biodegradable materials that dissolve over a desired period of time, as previously discussed with regard to the biodegradable sutures. [0088] One example device can be seen in Figure 20 which illustrates a shunt device 140 having a fenestrated body 142 defining a lumen 144 therethrough and anchoring features 146 and 148 on either side of the device 140. Anchoring features 146 and 148 are embodied as a plurality of petals. The device 140 is shown with an optional cover 154 spanning between the various features of the device 140. The cover 154 aids in anchoring the device 140 and preventing leakage of fluids around the device. In one embodiment, the device is composed of a biodegradable material, such as a polymer of poly-L lactic acid (PLLA), tyrosine-derived polycarbonate, polylactic acid, or a bioabsorbable metal of magnesium or zinc.

[0089] Figures 21 A, 21 B, and 22 illustrate another example embodiment of a shunt device 200 that can be implanted into an incision created surgically or by interventional techniques. Figures 21 A and 21 B illustrate the change in shape of one embodiment of a tubular shunt 100 of the present invention. In Figure 21 A, the shunt 200 is shown in a radially compressed configuration having a relatively long length 201 and a relatively small, uniform diameter 203. As the shunt 200 is deployed, its length substantially decreases to 20T and its diameter increases. More specifically, end portions 200A increase to a maximum radial diameter of 203’ and then decrease in diameter towards a middle region 200B, which has a diameter of 203”. In one embodiment, the device is composed of a biodegradable material, such as polymer of poly-L lactic acid (PLLA) or a bioabsorbable metal of magnesium.

[0090] In one example, when compressed, the shunt 200 has a length 201 of about 20 mm and a diameter 203 of about 1 .5 mm, and when expanded the shunt 200 has a diameter 203’ of the end portions 200A of about 8 mm and a diameter 203” of the middle region 200B of about 5 mm.

[0091] In another example, when compressed, the shunt 200 has a length 201 of about 30 mm and a diameter 203 of about 2.2 mm, and when expanded the shunt 100 has a diameter 203' of the end portion 100A of about 8 mm and a diameter 203” of the middle region 200B of about 4 mm.

[0092] In another example, when compressed, the shunt 200 has a length 101 of about 22 mm and a diameter 203 of about 3.5 mm, and when expanded the shunt 200 has a diameter 203' of the end portion 200A of about 24 mm and a diameter 203” of the middle region 200B of about 20 mm.

[0093] The shunt 200 includes a plurality of tubular radial bands that are each formed from a plurality of uniform, alternating waves that create the shunt passage 200C. Put another way each radial band 207 comprises a plurality of straight regions 207B joined together to create a pattern of triangular peaks 207A that alternate their longitudinal directions. The peaks 207A of each radial band 207 are aligned with each other and connected via a small, straight portion 209, which effectively creates diamond-shaped cells 202 when radially compressed. As a result of this design, the angle of each peak 207A increases as the shunt 200 is radially expanded and the radial bands 207 become closer together to each other, which causes longitudinal foreshortening (i.e. , a decrease in length of the shunt 200).

[0094] One mechanism for causing the radial flaring of the ends 200A of the shunt 200 is by creating a pattern of cells 202 in which some cells 202 are longer in their proximal-to-distal length than other cells 202 (i.e., they have longer straight regions 207B). Preferably, cells 202 in the middle of the shunt 200 have the smallest length and each row of cells 202 progressively increase in length the further away from the middle they are. Alternately, larger length cells 202 can be located only near the ends of the shunt 200.

[0095] The device may further incorporate a flow control device that allows flow through the lumen in only one direction, or allows flow through the lumen in only one direction and only if certain parameters are met. Alternatively, the device may further incorporate a flow control device that allows flow through the lumen in both directions, but only when certain parameters are met. The parameters that must be met in a first direction for fluid flow to be established may be the same or different than the parameters that must be met for fluid to flow in a second direction.

[0096] Adaptive shunt designs vary the flow profile based upon the pressure drop across the device. The principal of an adaptive shunt is such that the degree of shunting conferred by the device can be changed by intrinsic local conditions in response to a change in hemodynamic and/or anatomic parameters around which the device is placed. Such parameters may include, but are not limited to pressure, pressure gradient, absolute flow or flow gradients. The relationship between shunting and stimulus-response can be linear or nonlinear depending on the requirements of the individual situation. In addition to linearity/nonlinearity, thresholds can be built into such a shunt which function to begin or cease shunt at specific local conditions. These are‘onset’ or‘offset’ thresholds. In each case, for example, pressure or flow acts to change the effective shunt lumen size (open, close, other). The opening, if made highly nonlinear, can affect a‘snap open’ or‘snap closed’ result, effectively being a gating function of flow, pressure, or another regulated parameter.

[0097] The purpose of adaptive shunting is to protect organs or biologic tissues from pressure or flow damage. This protection may be conferred by limiting pressures at either the source or receiving end of the connection. For example, if the source of flow is the right heart, this chamber cannot sustain prolonged elevated pressures and a “bleed off” shunt could be used to drop pressures which are approaching or exceeding a specified threshold value. Such a threshold value may be variable and inherently built into the device such that the pressure-flow relationship is linear, or nonlinear of any sort to accommodate physiologic benefit. Similarly, elevated right heart pressures yield elevated pulmonary pressures which can damage lung tissue, causing scar and fibrosis with long-term catastrophic results if left unchecked. A response to increased pressure conditions during exercise may be possible with an adaptive shunt design as well.

[0098] Adaptive shunts may thus be used as regulators for a pressure-flow relationship and would thus be made to function in an“autoregulatory mode”. This feature is useful to maintain healthy and safe pressures (for example) or other parameters by shunting flow (or other parameters) into lower resistance, or higher compliance chambers or channels. An example of this is right heart and pulmonary hypertension which severely damages the right atrium, right ventricle and plumber tissues due to elevated pulmonary vascular resistance. By shunting blood flow partially into a compliant, low-pressure chamber, pressures are reduced.

[0099] In one example an adaptive shunt shunts more blood to the low-pressure chamber at higher pressures, feeding back on the source and lowering source pressure as it attempts to increase. Similarly, if pressure drops to lower levels the shunt will contract and shunt less blood from high-to-low pressure chamber, hence preventing the pressure to drop too low which would potentially dangerously reduce cardiac output.

[00100] Stent-like devices, like the shunt devices 140 or 200, can include valve mechanisms within their central passages to provide the previously discussed adaptive flow shunting. In one example, a conical member 150 composed of elastic material can be mounted within the central passage of a shunt device, moving from a relatively closed position (Figure 23A) to a relatively open position (Figure 23B). In another example, a relatively flat disc 160 can include a plurality of slits 162 that move from a closed position (Figure 24A) to an open position (Figure 24B). Other example mechanisms include spring mechanisms attached to a valve member, flaps, braided structures biased to a closed position that can be forced open, and other similar mechanisms.

[00101] While it is primarily contemplated that the shunts of the present invention be open for only a short period of time (e.g., 1 -4 weeks), the shunts may also be permanently held open to help treat additional conditions. For example, if the shunts are created post-operatively in a heart failure patient, maintaining the shunt permanently open may be helpful for long term dyspnea relief.

[00102] In one embodiment according to the present invention, any of the shunt creation methods described in this specification are first preceded by performing a separate surgical or interventional procedure on a patient. The shunt creation method may be performed at the end of the procedure or a short time later (e.g., 1 -3 days later). In another embodiment according to the present invention, any of the shunt creation methods described in this specification are performed prior to a surgical or interventional procedure on a patient.

[00103] One specific example is shown in Figures 26 and 27, in which a shunt is created after a retrograde cardioplegia procedure. As part of the retrograde cardioplegia procedure, a cardioplegia catheter 130 is advanced into the coronary sinus 19 from the superior vena cava and a balloon 134 is inflated to block off the flow of blood. After the procedure is complete, the cardioplegia catheter 130 can be advanced out of the coronary sinus 19 and into, for example the right ventricle 12. Next, a needle, a guidewire with a sharpened tip, or an RF ablation guidewire can be advanced through the cardioplegia catheter 130 to pierce the septum (e.g., ventricular septum 13 or atrial septum 17). While the cardioplegia catheter 130 has an inflatable balloon that could be used to expand the initial, pierced location to the desired size shunt, the cardioplegia catheter 130 can be removed and the existing guidewire used to advance a balloon catheter better suited for this task. Alternatively, any of the previously described shunt designs can be used to form the shunt.

[00104] In another embodiment according to the present invention, after one or more shunts are created in the patient’s septum, the patient’s outcome can be monitored by tracking one or more of the following: atrial pressures, atrial size, shunted flow, shunt size over time, ventricular hemodynamics, systemic and pulmonary pressures, and/or volume status.

[00105] In another embodiment, a tool from a separate treatment procedure can be temporarily left in place in order to prop open the shunt during post-operative care. Once the patient is ready for discharge, then the tool can be removed and the shunt closes. For example, most patients that undergo cardiac surgery have a chest tube left in place in order to help drain excess volume that accumulates in the chest cavity as a result of the surgery. This chest tube can be used to maintain a shunt in an open position while present but allows the shunt to close when removed.

[00106] Specifically, Figure 28 illustrates a shunt device 172 that is implanted at the time of an original treatment surgery. The shunt device 172 can be, for example, similar to either of the previously described devices 140 or 200. Flowever, the shunt device 172 further includes a flap or disc shaped valve member 172 that is connected along one or more sides so as to allow the valve member 174 to hinge open and closed over the passage of the device 172. Further, the valve member may be composed of or otherwise include a magnet or a material attracted to magnets. Additionally, the valve member 174 is biased to the closed position. For example, the valve member 174 may include or be attached with shape memory material (e.g., Nitinol) that is shape-set to bias the valve member 172 closed. [00107] The chest tube 176 may also include a magnet 178 (or magnetically attractive material if the valve member 174 includes a magnet). The magnet(s) are configured to have an attractive force strong enough to overcome both the bias of the hinge of the valve member 174 and any pressure from the beating of the heart 10 when the chest tube 176 is in its desired treatment position within the patient (e.g., between 1 -30 mm). In that respect, when the chest tube 176 is removed, along with its magnet 178, there is no longer any magnetic force capable of overcoming the bias of the valve member 174 to its closed position. Hence, the valve member 174 closes and thereby entirely blocks off the passage through the shunt device 170.

[00108] Figure 29 illustrates another embodiment in which a coronary sinus to central venous catheter 180 can be placed into the coronary sinus and crossed into the left atrium 18, through the atrial septum 17 to exchange blood flow between the left and right atria. The catheter 180 includes a first port 182 that is located at a position to be placed in the right atrium 16 and a second port 184 that is located at a position to be placed in the left atrium 18. Both ports 182, 184 are connected to a lumen 181 , which allows flow therebetween. Depending on the placement of the ports 182, 184, communication can also be established between the coronary sinus, inferior vena cava, and superior vena cava, in any combination.

[00109] An alternative placement of the catheter is in the coronary sinus. A RF wire is used to create a channel by which the catheter can be advanced into the left atrium. Once there, the communication channel can be opened as discussed above. Additionally, the catheter may have a housing at the distal tip that contains a deployable vascular closure device to close the hole in the coronary sinus / left atrial wall or the right atrial / left atrial septum, depending on where the communication was created. This closure device would allow for complete reversal of the treatment for POAF. The vascular closure device could be made of a nitinol scaffold covered with a bioresorbable polymer or it could simply be a patch-based, membrane-based, or suture-based closure system. These devices are commercially available and would be easily integrated into the catheter system.

[00110] In one embodiment seen in the side view of Figure 30, the catheter has a guidewire lumen 185 and an open, single drainage lumen 181 between the ports 182, 184. In another embodiment seen in Figure 31 , the drainage lumen 181 includes a one-way valve 186 that can be configured to allow blood flow only in one direction between the atria (i.e. , either right-to-left or left-to-right). In another embodiment seen in Figure 32, a third lumen 183 can be included for supplying drugs into the cardiovascular system, such as amiodarone to help with arrythmia management. In another embodiment, the catheter 180 may further include heart pacing elements configured to provide electrical signals for arrythmia management.

[00111] As seen in Figure 33, any of these catheter 180 embodiments can be connected or used with an existing central venous and arterial line system that are commonly used after cardiac surgery. A blood pump 188 can be connected to the catheter 180 and used to help pump blood between the two ports 182, 184. Pressure feedback from a pressure monitor measuring aortic pressure and central venous pressure can be communicated to the pump to allow the pump to significantly offload the pressure load on the atria while simultaneously preventing the lowering of central venous pressure to an undesirable level.

[00112] Some cardiac procedures require the surgeon to open the left or right atrium in order to perform valvular surgery. In these conditions the surgeon can easily and readily access the septum of the heart. In other cardiac procedures (i.e. CABG), they do not require the surgeon to open the heart chambers or place the patient on cardiopulmonary bypass. In these instances, it may be advantageous for the surgeon not to have to open the atrium or place the patient on bypass in order to create the shunt. In these instances, the surgeon can create an access site in the atrium and maintain hemostasis using a purse string suture or other techniques. The shunt creation tool can be inserted through the access site and target the septum of the heart, create the shunt, remove the tool and close the access site. This procedure can be performed under echo or fluoro guidance.

[00113] Alternatively, a shunt 192 can be created between the coronary sinus 19 and the left atrium 18. This can be performed according to any of the previously described techniques and devices. For example, in Figure 34 a physician can use a needle to puncture the exterior of the coronary sinus 19 and then cross directly into the left atrium 18. The physician may then exchange the needle for a guidewire 190, after which a dilator catheter 191 or balloon catheter can be advanced over the guidewire 190 and into the opening into the left atrium 18, increasing the size of the opening. The dilator 192 and then guidewire 190 can be removed and the external access site closed. In that respect, the shunt 192 (Figure 35) created can allow some blood to flow out of the left atrium and into the coronary sinus 19 to relieve pressure.

[00114] Alternately, the dilatory 191 can be removed and a delivery catheter can be advanced over the guidewire 190 to deliver one of the stent-like shunt devices discussed in this specification (e.g., device 140 or 200).

[00115] Alternately, instead of using a single needle, the previously discussed multi needle device 25 can be used to make a plurality of relatively small punctures/shunts between the coronary sinus 19 and the left atrium 18.

[00116] In another embodiment of the present invention it is contemplated that multiple shunts are created, at least one in an atrial septum and at least one in a ventricular septum. The size and location and duration of patency of these multiple shunts can be tailored to the needs and condition of the patient.

[00117] Although the invention has been described in terms of particular embodiments and applications, one of ordinary skill in the art, in light of this teaching, can generate additional embodiments and modifications without departing from the spirit of or exceeding the scope of the claimed invention. Accordingly, it is to be understood that the drawings and descriptions herein are proffered by way of example to facilitate comprehension of the invention and should not be construed to limit the scope thereof.

Claims

What is claimed is:

1 . A method of treating post-operative atrial fibrillation, comprising:

performing a surgery on a patient to treat a medical condition;

creating a shunt between a left atrium and a right atrium of the patient’s heart; the shunt creation being distinct from the treatment of the medical condition; and, lowering a pressure within the patient’s heart.

2. The method of claim 1 , wherein creating the shunt is performed by a surgical or interventional tool.

3. The method of claim 1 , wherein creating the shunt is performed by advancing a catheter into the heart, piercing an atrial septum, advancing the catheter through the atrial septum, and inflating a balloon on the catheter to increase a diameter of the shunt in the atrial septum.

4. The method of claim 1 , wherein creating the shunt further comprises creating the shunt with a diameter within a range of about 2-10 mm.

5. The method of claim 1 , wherein creating the shunt further comprises creating a plurality of shunts through an atrial septum.

6. The method of claim 5, wherein creating the plurality of shunts comprises creating 10-15 shunts with a diameter of about 2 mm each.

7. The method of claim 5, wherein creating the plurality of shunts comprises creating about 5-10 shunts with a diameter of about 3 mm each.

8. The method of claim 1 , wherein creating the shunt further comprises suturing biodegradable stitches adjacent to said shunt so as to temporarily maintain the shunt in an open configuration.

9. The method of claim 1 , wherein creating the shunt further comprises suturing a closure device around the shunt which is further configured to close the shunt after a predetermined period of time.

10. The method of claim 1 , wherein creating the shunt further comprises suturing a one-way valve over the shunt.

1 1 . A method of treating post-operative atrial fibrillation, comprising:

performing a surgery on a patient to treat a medical condition;

creating a shunt between a left ventricle and a right ventricle of the patient’s heart; the shunt creation being distinct from the treatment of the medical condition; and,

lowering a pressure within the patient’s heart.

12. The method of claim 1 1 , wherein creating the shunt is performed by a surgical or interventional tool.

13. The method of claim 1 1 , wherein creating the shunt is performed by advancing a catheter into the heart, piercing a ventricular septum, advancing the catheter through the ventricular septum, and inflating a balloon on the catheter to increase a diameter of the shunt in the ventricular septum.

14. The method of claim 1 1 , wherein creating the shunt further comprises creating the shunt with a diameter within a range of about 2-10 mm.

15. The method of claim 1 1 , wherein creating the shunt further comprises creating a plurality of shunts through a ventricular septum.

16. The method of claim 15, wherein creating the plurality of shunts comprises creating 10-15 shunts with a diameter of about 2 mm each.

17. The method of claim 15, wherein creating the plurality of shunts comprises creating about 5-10 shunts with a diameter of about 3 mm each.

18. The method of claim 11 , wherein creating the shunt further comprises suturing biodegradable stitches adjacent to said shunt so as to temporarily maintain the shunt in an open configuration.

19. The method of claim 11 , wherein creating the shunt further comprises suturing a closure device around the shunt which is further configured to close the shunt after a predetermined period of time.

20. The method of claim 11 , wherein creating the shunt further comprises suturing a one-way valve over the shunt.

21. A method of treating post-operative atrial fibrillation, comprising:

performing a retrograde cardioplegia procedure on a patient with a cardioplegia catheter;

advancing the cardioplegia catheter from a coronary sinus into a right atrium of the patient’s heart;

creating a shunt through a septum of the heart.

22. The method of claim 21 , wherein the shunt is created in either the atrial septum or the ventricular septum.

23. A method for closing a shunt after a predetermined period of time, comprising: creating a shunt through a septum of a heart;

positioning a frame around a device, the frame having a radially expanded configuration and a radially contracted position;

suturing both degradable stitches and nondegradable stitches to the frame and to tissue surrounding the shunt;

allowing the degradable stitches to dissolve and the frame to move to the radially contracted position to thereby close the shunt.

24. A method of treating post-operative atrial fibrillation, comprising:

performing a surgery on a patient to treat a medical condition; creating a shunt through a septum of the patient’s heart; the shunt creation being distinct from the treatment of the medical condition; and,

fixing a one-way valve to the shunt.

25. A method of treating post-operative atrial fibrillation, comprising:

performing a surgery on a patient to treat a medical condition;

advancing a distal end of a shunt tool into a heart;

pressing a plurality of needles on the shunt tool into a septum of the heart to create a plurality of shunts.

26. A shunt device, comprising:

a frame formed from a plurality of struts that are each connected to each other to form a multisided planar shape surrounding a center space;

the frame having a radially expanded configuration in which the center space is a first size, and a radially compressed configuration in which the center space is a second size that is smaller than the first size; and,

the frame having a plurality of connection points that are each configured to receive stiches;

wherein the frame is biased to the radially compressed configuration when unrestrained, and;

wherein the frame is configured to be attached around a tissue aperture in the radially expanded configuration with both biodegradable stitches and degradable stitches such that when the biodegradable stitches dissolve, the frame moves to the radially compressed configuration and close the tissue aperture.

27. The shunt device of claim 26, wherein the frame has a square shape in the radially expanded configuration and a star shape in the radially compressed configuration.

28. A shunt device kit, comprising:

biodegradable stitches. nondegradable stitches; and,

wherein the frame is configured to be attached around a tissue aperture in the radially expanded configuration with both the biodegradable stitches and the degradable stitches such that when the biodegradable stitches dissolve, the frame moves to the radially compressed configuration and close the tissue aperture.

29. A shunt device, comprising:

an elongated body having a distal end;

a plurality of needles extending distally and longitudinally relative to the elongated body; and,

a sheath disposed over the elongated body and configured to slide between a first position covering the plurality of needles and a second position exposing the plurality of needles.

30. The shunt device of claim 29, wherein the plurality of needles are within a range of 5mm - 20mm long.

31. The shunt device of claim 29, wherein the plurality of needles are within a range of 10mm - 30mm long.

32. A method of treating post-operative atrial fibrillation, comprising:

performing a surgery on a patient to treat a medical condition; creating an opening between a septum of the patient’s heart;

implanting a biodegradable shunt scaffolding in the opening to create a shunt, the shunt creation being distinct from the treatment of the medical condition; and, lowering a pressure within the patient’s heart.

33. A temporary shunt system, comprising:

a chest tube;

a shunt scaffold having a valve member having an open position allowing flow through the shunt scaffold and a closed position that substantially prevents flow through the shunt scaffold;

wherein the valve member is biased to the closed position; and,

wherein the valve member and the chest tube are configured to engage with magnetic force to over the bias of the valve member to the closed position and maintain the valve member in the open position when in close proximity to each other.

34. A method of treating post-operative atrial fibrillation, comprising:

performing a surgery on a patient to treat a medical condition;

creating a shunt between a coronary sinus and a left atrium of the patient’s heart; the shunt creation being distinct from the treatment of the medical condition; and,

lowering a pressure within the patient’s heart.

35. The method of claim 34, wherein the shunt is created via a needle or a multi needle tool.

36. The method of claim 34, wherein the shunt is created via a needle or a multi needle tool.

37. The method of claim 34, further comprising placing a shunt scaffold in the shunt.

38. A method of treating post-operative atrial fibrillation, comprising:

performing a surgery on a patient to treat a medical condition; creating a shunt between a left atrium and a right atrium of the patient’s heart; the shunt creation being distinct from the treatment of the medical condition;

positioning a catheter between the left atrium and the right atrium;

allowing drainage between the left atrium and the right atrium via the catheter; and,

lowering a pressure within the patient’s heart.

39. The method of claim 38, wherein the catheter is further connected to a pump configured to assist in reducing pressure within the patient’s heart.

40. A system for treating POAF comprising: a device configured to create a passage between at least one septum of a heart; at least one shunt device configured to maintain patency of said passage; a device configured for measuring the electrical impulses of a beating heart; a device configured for measuring a pressure of a patient’s heart.