The various chambers of the heart may respond to pressure increases by stretching to hold more blood to pump through the body or by becoming relatively stiff and/or thickened. The walls of the heart can eventually weaken and become unable to pump as efficiently. In some cases, the kidneys may respond to cardiac inefficiency by causing the body to retain fluid. Fluid build-up in arms, legs, ankles, feet, lungs, and/or other organs can cause the body to become congested, which is referred to as congestive heart failure. Generally, left atrial pressure may be relatively highly correlated with risk of congestive heart failure. Furthermore, there may generally be a relatively strong correlation between increases in left atrial pressure and pulmonary congestion. Acute decompensated congestive heart failure is a leading cause of morbidity and mortality, and therefore treatment and/or prevention of congestive heart failure is a significant concern in medical care. Embodiments of the present disclosure can serve to treat and/or prevent congestive heart failure through reduction in left atrial pressure in patients suffering from high left atrial pressure.

Generally, increases in ventricular filling pressures associated with diastolic and/or systolic heart failure can occur prior to the occurrence of symptoms that lead to hospitalization. For example, cardiac pressure indicators may present weeks prior to hospitalization with respect to some patients. Therefore, reduction in left atrial and/or ventricular pressure in accordance with embodiments the present disclosure may advantageously be implemented as a preventative measure to reduce risks of hospitalization and/or the onset of heart failure.

Determination of high left atrial pressure may be made in any suitable or desirable way. Dyspnea represents a cardiac pressure indicator characterized by shortness of breath or the feeling that one cannot breathe well enough. Dyspnea may result from elevated atrial pressure, which may cause fluid buildup in the lungs from pressure back-up. Therefore, it may be desirable to implement certain left atrial pressure reduction solutions presented herein in response to dyspnea symptoms. Additionally or alternatively, left atrial pressure reduction in accordance with embodiments or the present disclosure may be implemented prior to manifestation of dyspnea symptoms and/or other symptoms/complications through direct and/or indirect pressure (e.g., left atrial pressure) monitoring and/or intervention. For example, left atrial pressure monitoring may be implemented using one or more sensors implanted or disposed in one or more chambers of the heart, such as within the left atrium. In some implementations, left atrial pressure may be derived or inferred through measurement of other chambers or vessels of the heart, which may serve as surrogates of left atrial pressure, such as measurements of pressure in one or more of the right atrium, right ventricle, pulmonary artery, and/or pulmonary artery wedge.

Left Atrial Pressure Reduction Using Fluid Bypass Conduit Implant Devices and Processes

As described above, pressure elevation the left atrium may be correlated with certain heart failure conditions, as well as pulmonary congestion. Various medical conditions can lead to elevated left atrial pressure, including diastolic heart failure, systolic dysfunction of the left ventricle, and valve disease. Furthermore, both heart failure with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HFrEF) can present with elevated left atrial pressure. These conditions can benefit from a reduction in left atrial pressure, which in turn generally reduces the systolic preload on the left ventricle. Reduction in left atrial pressure can also advantageously relieve pressure on the pulmonary circulation, reducing the risk of pulmonary edema, improving respiration and/or improving patient comfort. Embodiments of the present disclosure advantageously provide systems, devices, and methods for reducing left atrial pressure. In some implementations, left atrial pressure reduction is achieved by shunting an amount of blood flow, that otherwise would flow from the left atrium into the left ventricle and be ejected through the aortic valve during systole, through the left atrium to a flow path associated with the right side of the heart, such as through the interatrial septum or coronary sinus and into the right atrium. Disclosed herein are fluid bypass conduit devices, and methods of using the same, configured to provide such shunting through the left atrium.

FIG. 3 illustrates a heart 1 having a fluid bypass conduit device 50 implanted therein. Embodiments of the present disclosure relate to systems, devices, and methods for implanting fluid bypass conduit implant devices that may be similar in certain respects to the device 50 shown in FIG. 3, which may be configured to shunt or bypass blood flow from one area of the patient's vasculature to another. For example, embodiments of the present disclosure may advantageously involve shunting blood flow from an area in fluid communication with the left atrium 2, or other chamber or vessel associated with the left side of the heart, to the right side of the heart to thereby reduce left atrial pressure. Such methods may involve anchoring a first end 52 (e.g., distal end) of the fluid bypass conduit devices 50 on or in a pulmonary vein 26 and/or pulmonary vein ostium 25. The second end 54 (e.g., proximal end) of the fluid bypass conduit device 50 may be anchored in and/or through an interatrial septal wall 18 or ventricular septal wall 17 to provide fluid access from the pulmonary vein 26 and/or left atrium 2 into the right side of the heart, such as into the right atrium 5.

In some implementations, processes in accordance with the present disclosure involve implanting a fluid bypass conduit device such that a first end of the device is anchored in or to a pulmonary vein and/or pulmonary vein ostium, whereas the opposite end or portion of the implant device is anchored or secured to a wall or anatomy providing access to the coronary sinus. That is, the fluid bypass conduit device may advantageously provide fluid coupling between one or more pulmonary veins and the coronary sinus, which can allow for blood flow to drain from the left side of the heart into the right side of the heart (e.g., right atrium) via the coronary sinus.

As described above, the pulmonary veins 23, 26 transfer oxygenated blood from the lungs (not shown) to the heart 1. Generally, the largest pulmonary veins are the four main pulmonary veins 23, 26 (see FIGS. 1 and 2), two from each lung that drain into the left atrium 2. The pulmonary veins are part of the pulmonary circulation. Two main pulmonary veins emerge from each lung hilum, receiving blood from three or four bronchial veins apiece and draining into the left atrium 2. Generally, an inferior and superior main vein drains each lung, providing the four main veins shown in FIGS. 1 and 2. As shown in FIGS. 1 and 2, the left 26 and right 23 pulmonary veins generally enter the left atrium 2 via the posterior left atrial wall.

With further reference to FIG. 3, the fluid bypass conduit device 50 may be configured and/or shaped such that blood flow from the pulmonary veins is channeled at least partially within a lumen or channel 55 of the implant device 50 into the right atrium 5, thereby at least partially bypassing the left atrium 2 and/or ventricle 3. Attachment to the atrial septum wall 18 may be made in such a way as to allow for blood flow through the atrial septum 18 via the internal channel 55 of the bypass implant device 50. For example, a hole or opening may be formed in the septum 18 such that the implant bypass channel 55 passes through the septal wall 18.

The ends of the implant device 50 may be sutured or anchored to their respective target tissue, such as a pulmonary vein and/or septal wall, in any suitable or desirable way. As used herein, the term “pulmonary vein” may refer to a pulmonary vein ostium, vessel interior, and/or portion of left atrial tissue surrounding a pulmonary vein ostium. Furthermore, attachment or engagement with a pulmonary vein by a fluid bypass implant device and/or one or more anchor features associated therewith, as described herein, should be understood to relate to engagement or attachment of a fluid bypass implant device and/or associated anchor(s) with any tissue associated with the pulmonary vein, including at least a pulmonary vein ostium, vessel interior, and/or portion of left atrial tissue surrounding a pulmonary vein ostium. By anchoring the fluid bypass implant device 50 in the pulmonary vein 26 and/or ostium 25 associated therewith, blood flow from the pulmonary vein 26 can be channeled within the implant device into the right atrium 5, thereby bypassing the left atrium 2. The term “associated with” is used herein according to its broad and ordinary meaning. For example, where a first feature, element, component, device, or member is described as being “associated with” a second feature, element, component, device, or member, such description should be understood as indicating that the first feature, element, component, device, or member is physically coupled to, attached to, connected to, integrated with, embedded at least partially within, or otherwise physically related to the second feature, element, component, device, or member, whether directly or indirectly. Although certain embodiments are disclosed herein relating to anchoring of a fluid bypass implant device to a right and/or upper pulmonary vein, it should be understood the embodiments disclosed herein can involve anchoring or implanting of fluid bypass implant devices and/or anchor feature(s) thereof to any pulmonary vein or other vessel open to and/or associated with the left atrium or other chamber of the heart or body.

Attachment to the atrial septum wall 18 may be made in such a way as to allow for blood to flow through the atrial septum 18 via the internal channel 55 of the bypass conduit device 50. For example, a hole or opening may be formed in the septum 18 such that the implant bypass channel 55 passes through the septal wall 18. With the conduit device 50 engaged with a single pulmonary vein 26, only a fraction of the total blood supplied to the left atrium 2 via the pulmonary veins may be re-routed to the right side of the heart 1. In some implementations, engagement with one pulmonary vein may divert approximately 25% of the total oxygenated blood flow from the lungs to the left atrium 5 and/or left ventricle 4.

Although a single pulmonary vein is shown in FIG. 3 as being engaged by the device 50, in some embodiments, the device may couple to more than one pulmonary vein, or more than one fluid bypass conduit implant device may be employed, to provide increased pressure reduction. For example, the device 50 may have a manifold-type configuration, wherein multiple distal channels of the device are combined together and directed towards the opening in the septal wall.

In some embodiments, the implant device 50 may comprise a tubular, or partially-tubular member or portion 59 having one or more anchors associated with respective ends thereof. The tubular section 59 may advantageously comprise a self-expanding tubular structure. Furthermore, the fluid bypass conduit 50 may comprise a fluid-tight covering around at least a portion of the tubular component (e.g., internal frame) 59. In some embodiments, the tubular portion 59 does not include an internal frame. One end 52 (e.g., distal end) of the fluid bypass conduit 50 may be implanted in the pulmonary vein 26 and/or pulmonary vein ostium 25. An opposite end 54 (e.g., proximal end) of the conduit device 50 may be implanted through the interatrial septal wall 18 to provide fluid access through the channel 55 of the conduit device 50 from the pulmonary vein 26 into the right atrium 5. In some embodiments, rather than providing fluid access through the interatrial septum wall 18, the conduit device 50 may be implanted in the pulmonary vein 26 and/or pulmonary vein ostium 25, whereas the opposite end of the device 50 may be implanted in a wall of the left atrium in a position to provide fluid access through the channel 55 into the coronary sinus 16 (see FIGS. 2 and 10).

The fluid bypass conduit device 50 may act as a bypass channel connecting or tapping from one or more of the four pulmonary veins and redirecting or shunting blood flow from the vein(s) directly into the right atrium 5 through the septal wall 18. By bypassing blood flow from one or more pulmonary veins to the right atrium, fluid that otherwise would fill the left atrium and increase fluid pressure therein can be channeled instead into the right atrium, thereby reducing left atrial pressure, and accordingly reducing risk of heart failure and/or other health complications.

The anchor feature(s) 53 associated with the distal end 52 of the fluid bypass conduit device 50 may be any type of tissue anchor or engagement feature(s). For example, in some embodiment, the anchor feature(s) 53 are friction-fit, tissue-engagement anchors, such as one or more self-expanding stent features. The anchor feature(s) 51 associated with the proximal end 54 of the fluid bypass conduit device 50 may be similar or different type(s) of anchor feature(s) than the anchor feature(s) 53. For example, the anchor feature(s) 51 may comprise one or more wire and/or coil forms having a width or diameter dimension greater than the opening in the septum 18 and configured to prevent the proximal end 54 of the device 50 from being drawn or pulled through the opening into the left atrium 2.

The fluid bypass conduit device 50 can inhibit undesirable expansion or dilation of the left atrium 2 once it is implanted in accordance with some implementations. That is, the fluid bypass conduit device 50 can advantageously serve to prevent the left atrium 2 and/or other chamber of the heart 1 from dilating or expanding due to undesirable enlargement. For example, the bypass fluid conduit 50 (e.g., a metal frame thereof (see frame 37 of FIG. 6) and/or other component of the bypass fluid conduit) can act as a tensioning device to prevent possible enlargement of the left atrium. Some embodiments include a self-expanding memory metal frame and/or an at least partially fluid-tight covering. Although a variety of features of the fluid bypass conduit device 50 are shown in FIG. 3, it should be understood that features can be implemented independently of any of the other features shown and described.

FIG. 4 is a flow diagram illustrating a process 400 for reducing left atrial pressure using one or more fluid bypass conduit implant devices in accordance with one or more embodiments of the present disclosure. FIG. 5 shows certain cross-sectional images of cardiac anatomy and certain devices associated with the process 400 of FIG. 4 to illustrate aspects of the process 400 according to one or more implementations thereof.

At block 402, the process 400 involves advancing a delivery catheter and/or sheath 40 to a right atrium 5 of a patient percutaneously through a transcatheter access path. For example, access to the right atrium 5 may be made via the inferior vena cava 29 or superior 19 vena cava. For example, as shown in image 502, the delivery catheter 40 may be advanced to the right atrium 5 through an inlet opening 21 from the superior vena cava 19 or through the inlet opening 27 from the inferior vena cava 29. The terms “catheter” and “sheath” are used herein according to their broad and ordinary meanings and may refer to any type of tube suitable for insertion in the body. “Catheter” and “sheath” may be used substantially interchangeably is some contexts herein.

Although not shown in FIG. 5 or described in detail herein for clarity purposes, processes for deploying and/or implanting fluid bypass conduit devices in accordance with embodiments of the present disclosure may involve introducing a guidewire through the relevant access path prior to deployment of the delivery catheter 40. Once the guidewire provides a path, an introducer sheath (not shown) may be routed along the guidewire and into the patient's vasculature. For example, the introduction of the introducer may be achieved with the use of a dilator. The introducer sheath may advantageously provide a hemostatic valve to prevent blood loss.

The delivery catheter 40 may contain therein a fluid bypass conduit device 60 in accordance with embodiments of the present disclosure. At block 404, the process 400 involves advancing the delivery catheter 40 through the interatrial septum 18 to access the left atrium 2. For example, the delivery catheter 40 may function to form and prepare an opening in the atrial septum 18. In some implementations, a separate placement or delivery catheter can be used for delivery of the fluid bypass implant device. In other embodiments, the delivery catheter may be used as the both the puncture preparation and fluid bypass conduit device placement catheter. In the present application, the term “delivery catheter” is used according to its broad and ordinary meaning and can refer to a catheter or introducer with one or both of these functions. At block 406, the process 400 involves advancing the delivery catheter 40 into or adjacent to a pulmonary vein or pulmonary vein ostium 25.

At block 408, the process 400 involves anchoring a distal end of the fluid bypass conduit device 60 transported within the delivery catheter 40 to the pulmonary vein 26 and/or pulmonary vein ostium 25. The conduit device 60 can comprise a generally tubular body or sleeve defining a lumen. The distal end of the conduit device 60 may serve as a fluid inlet. The distal end of the conduit device 60 may be associated with one or more anchoring features 63, which may be used to anchor the conduit device 60 to the pulmonary vein 26. The anchor feature(s) 63 may comprise, for example, one or more barb- or corkscrew-type tissue anchors and/or a stent form for anchoring to and/or in the pulmonary vein 26.

The bypass fluid conduit device 60 may be implanted at or in the pulmonary vein 26, 25 in such a way as to effectively fluid-seal the target pulmonary vein. Alternatively, the distal end of the conduit device 60 may be implanted or anchored at the pulmonary vein or pulmonary vein ostium in such a way as to include gaps or spaces around a periphery of the conduit device 60 through which blood may flow. Such gaps or spaces may be intentionally and/or deliberately allowed or implemented or may result naturally from imperfect sealing or anchoring of the conduit device 60. Although the process 400 is described as involving first implanting the conduit device 60 in the pulmonary vein and secondly implanting the proximal end of the device 60 in the septum 18, in some implementations, the fluid bypass conduit device 60 may first be anchored to the septum 18, after which one or more of the pulmonary veins may be identified as providing a desired or ideal output or reduction in pressure, and such identified vein(s) may be coupled to the conduit device 60.

As described above, four separate pulmonary veins, two from the right and two from the left, may channel blood into the left atrium 2. Therefore, each of the pulmonary veins individually contributes only a portion of the total inlet flow into the left atrium 2. In some embodiments, the target pulmonary vein 26 may be selected to optimize an amount of blood flow shunted from the left side of the heart to the right. For example, the process 400 may involve selecting a desired one or number of pulmonary veins designed to provide the desired portion of the inlet blood flow from the lungs through the bypass conduit device 60. In some patients, a fluid bypass conduit device coupled to a single pulmonary vein may channel approximately 25% of the inlet blood flow into the left atrium 2 to the right side of the heart. Therefore, left atrial pressure may be reduced by approximately 25%, or some other percentage between 0-25%, by implanting a fluid bypass conduit device in accordance with embodiments of the present disclosure between a single pulmonary vein and the right atrium or ventricle via a septal or atrial wall.

At block 410, the process 400 involves withdrawing the delivery catheter 40 back to and/or through the interatrial septum 18, thereby deploying a medial channel portion of the fluid bypass conduit 60 and exposing the same in the left atrium 2. The bypass conduit device 60 may advantageously be at least partially self-expanding, and may include a jacket or cover, which may comprise thin PTFE material or similar, or biological tissue. The medial portion of the conduit device 60 can comprise an at least partially rigid frame, which may comprise an expandable laser-cut metal frame and/or one or more annular hoops covered by a sleeve or covering. The frame can be generally cylindrical with respect to a cross-sectional shape thereof over at least a longitudinal portion of the conduit form of the device 60, as shown in various figures and described in certain contexts herein. The medial portion of the conduit device 60 may advantageously be at least partially flexible and may be pre-formed into a desired (e.g., at least partially curved) shape. The conduit device 60 can be advanced from the delivery catheter by pushing the conduit device 60 out of the delivery catheter 60 and/or retracting the delivery catheter 40 relative to the conduit device 60. In some implementations, a pusher device extending axially through at least a portion of the delivery catheter 40 may be used to assist in deploying the conduit device 60 from the catheter.

At block 412, the process 400 involves anchoring a proximal end of the fluid bypass conduit device 60 to the interatrial septum 18, such that the internal fluid channel of the conduit 60 provides a pathway from the pulmonary vein 26 through the atrial septum 18 and into the right atrium 5. The anchor feature(s) 61 associated with the proximal end of the conduit device 60 may be any type of anchor features, including expanding coils or arms, or barb-type anchors configured to embed in the tissue of the septal wall 18. Although certain portions of the description herein are focused on shunting through the atrial septum 18, it should be understood that in some embodiments shunting may be through a left atrial wall between the left atrium 2 and the coronary sinus, wherein shunting to the right side of the heart is via the coronary sinus and Thebesian valve into the right atrium 5

At block 414, the process 400 involves withdrawing the delivery catheter 40 from the heart of the patient, thereby leaving the fluid bypass implant device 60 implanted as shown in image 514. Due to the generally higher-pressure state in the left side of the heart compared to the right side of the heart, fluid back flow from the right atrium to the left side of the heart may generally not occur in the steady-state implanted condition. With the delivery catheter withdrawn, the fluid bypass conduit device 60 can advantageously provide shunting from the left side of the heart to the right side of the heart, as described above.

FIG. 6 illustrates an embodiment of a fluid bypass conduit device 30 in accordance with one or more embodiments. The conduit device 30 may be a self-expanding implant device in accordance with embodiments disclosed herein. In some embodiments, the fluid bypass conduit device 30 comprises a self-expanding stent or frame component 37, which may be shaped and configured to form a conduit, such as a cylindrical-cross-sectional conduit, as described herein. Although self-expanding frames and conduits are described herein, in some embodiments, a fluid bypass conduit device may be balloon-expandable or may not require expansion after deployment from the delivery catheter. Furthermore, although transcatheter processes are described herein, in some embodiments, access to the left ventricle may be implemented via surgical access or minimally invasive access (e.g., transthoracic access).

Opposite ends 32, 34 of the conduit formed by the frame 37 can be coupled to and/or otherwise associated with one or more anchor components 31, 33, respectively. The device 30 shown in FIG. 6 is illustrated in an expanded configuration. In a compressed or collapsed configuration, the device 30 may be transportable to a target implantation location using a catheter via femoral or jugular access and crossing through the interatrial septum or other path to the left atrium. The image of FIG. 6 shows barb-type tissue anchors 31, 33. However, it should be understood that any types of anchors may be utilized in connection with fluid bypass conduit devices in accordance with embodiments of the present disclosure.

Although certain embodiments are disclosed herein showing a single fluid bypass conduit device and/or a fluid bypass conduit device implanted in only a single pulmonary vein, in some implementations, a fluid bypass conduit device may be implanted in fluid communication with more than one pulmonary vein. For example, such implementations may utilize two separate conduit devices, or may utilize a single conduit device having a plurality of distal conduit openings/inlets for implantation in more than one pulmonary vein. Additional pulmonary veins may be tapped in order to provide the desired pressure-reduction functionality.

The tissue anchors 31, 33 shown in FIG. 6, as well as those described in connection with other embodiments of the present disclosure, may be any suitable or desirable types of tissue anchors. For example, in some embodiments, a tissue anchor associated with a fluid bypass conduit device comprises a pre-shaped wireform, such as a loop, coil, spiral, or the like, which may be configured to assume a relatively wide tissue anchor profile once deployed from the delivery catheter. Other types of tissue anchors that may be used include, but are not limited to, tension-fit or resistance-fit tissue anchors, such as stents or the like, barb-type tissue anchors, which may incorporate tip features configured to resist withdrawal of the anchor tip(s) from tissue in which it is embedded following embedding, corkscrew-type tissue anchors, and/or other types of tissue anchors that may or may not be known in the art.

As described in detail herein, the fluid bypass conduit device 30 may advantageously be dimensioned to have a length L sufficient to traverse the left atrium of the patient. For example, the fluid bypass conduit device 30 may have a length of approximately 2-5 cm. In some embodiments, the length L of the device 30 is approximately 4 cm. In some embodiments, the conduit device 30 is configured to have a variable length, wherein the length of the conduit may adjust or flex in response to contraction of the atrium. That is, the fluid bypass conduit device 30 may advantageously be configured with self-expansion characteristics allowing for expansion and/or contraction of the atrium being absorbed by the frame 37 and/or other components of the device 30. In some embodiments, the fluid bypass conduit device 30 advantageously includes a covering 39, which may be disposed within or without the frame 37, and may be at least partially fluid-tight, to thereby facilitate funneling or channeling of blood flow through the medial portion/segment 35 of the conduit device 30. Although a variety of features of the fluid bypass conduit device 30 are shown in FIG. 6, it should be understood that such features can be implemented independently of any of the other features shown and described.

FIG. 7 shows a top-down view of a left atrium 2 having implanted therein a fluid bypass conduit device 70 in accordance with one or more embodiments of the present disclosure. The conduit device 70 shown in FIG. 7 includes various features that may be incorporated in any of the disclosed embodiments. For example, the conduit device 70 includes an accordion-type shock absorber feature 78, which may be part of, or incorporated in, one or more of an internal frame and/or covering 79 of the conduit device 70, as described in detail herein. The feature can generally be configured to axially contract and/or allow for axial contraction of the conduit device 70. For example, the feature 78 may comprise a plurality of pleated layers that may be integrated with the covering 79 and allow for longitudinal expansion and contraction of the conduit device 70. The shock-absorber feature 78 may advantageously be compressible to accommodate reduction in longitudinal length of the conduit in connection with contraction of the atrium 2.

In some embodiments, the conduit device 70 may comprise one or more holes or apertures in the covering 79 to allow for fluid outflow into the atrium 2. For example, some embodiments may allow for selective opening formation in the covering 79 and/or one or more other components of the conduit device 70 to adjust the pressure reduction effect of the conduit device 70. That is, the conduit device 70 may allow for adjustable shunting functionality. For example, in some embodiments, the conduit device 70 may comprise adjustable shunting mechanisms, such as certain holes or apertures in the covering and/or other features of the conduit device 70 that may become more or less offset with respect to one another in an overlapping configuration in response to increased pressure or other modifications of the device 70 or environment. Therefore, in some embodiments, the increased pressure within (or without) the conduit 70 can results in larger opening(s) in the covering 79 and/or other components of the device 70, such that additional blood may flow from the conduit 70 into the atrium 2. In some implementations, axial rotation implemented on the conduit device 70 and/or one or more components thereof may serve to restrict or open blood flow, thereby modifying the characteristics of the conduit device 70. Adjustable shunting features may comprise any form or type of mechanism that serves to make the conduit 70 and/or one or more components thereof more or less porous to blood flow. In some embodiments, the conduit device 70 may have compliance characteristics to allow for expansion thereof under certain high-pressure conditions.

As described in detail herein, tissue-anchoring components or portions of a fluid bypass conduit device in accordance with embodiments of the present disclosure may comprise any suitable or desirable form or mechanism, including any known tissue-anchoring devices or mechanisms. In the illustrated embodiment of FIG. 7, the conduit device 70 advantageously includes an expandable (e.g., self-expanding and/or memory metal) anchor 71 associated with a proximal 72 (or distal 74) end portion of the conduit device 70. For example, the expandable anchor 71 may have a diameter d in an expanded configuration that is greater than one or both of a diameter of the opening 85 in the atrial septum 18 and the diameter of the conduit device 70, such that the anchor 71 retains the conduit device 70 in place and prevents the proximal end 72 of the conduit device 70 from being pulled through the opening 85 in the atrial septum 18 into the left atrium 2.

One end, such as the distal end 74, of the conduit device 70 may be associated with a tension/resistance anchor, such as a stent 73 or similar structure or device. For example, the stent 73 may be expanded within a pulmonary vein 26, as shown. In some embodiments, the conduit device 70 may be anchored to more than one pulmonary vein. For example, an anchor 73 or distal and portion 74 of the conduit device 70 may be associated with a clip or arm feature 76, which may be configured to be disposed within, or otherwise anchored to, an adjacent pulmonary vein 24 and/or ostium thereof 25b, such as being clipped to an inside wall of the pulmonary vein 24, as shown. The clip or arm member 76 may be configured to provide inward radial force with respect to the axis of the conduit device 70 to thereby provide additional anchoring of the conduit device 70 to the second pulmonary valve 24 as well.

In some embodiments, anchoring between adjacent pulmonary veins may be accomplished using a tension/resistance anchor 87 in the adjacent pulmonary vein 24, as shown in FIG. 8. In FIG. 8, a first anchor stent 83 is deployed in a first pulmonary vein 26, wherein the stent 83 is associated with and/or coupled to a distal end portion of a fluid bypass conduit device (not shown) in accordance with embodiments of the present disclosure. The first anchor 83 is coupled to a secondary anchor 87 deployed within the adjacent pulmonary vein 24, wherein the first and second anchors 83, 87 are coupled to one another by a bridge or arm member 86, which may be at least partially rigid and/or flexible. In some embodiments, the bridge/arm member 86 has shape memory and/or resilience characteristics that introduce a force on the anchors 83, 87 towards one another. Either or both of the anchors 83, 87 may be self-expanding stents. Implementation of a secondary anchor 87 and bridge/arm member 86 may serve to provide improved anchoring for a fluid bypass conduit device in accordance with embodiments of the present disclosure. Although a variety of features shown in FIGS. 7 and 8, it should be understood that such features can be implemented independently of any of the other features shown and described.

Fluid Bypass Through the Coronary Sinus

As an alternative to using a fluid bypass conduit device to fluidly couple a pulmonary vein to the right side of the heart through the interatrial septum, principles disclosed herein are applicable to other implantation configurations, including fluidly coupling one or more pulmonary veins to the right side of the heart via the coronary sinus. FIG. 9 is a flow diagram illustrating a process 900 for reducing left atrial pressure using one or more fluid bypass conduit implant devices configured to fluidly couple one or more pulmonary veins to the coronary sinus in accordance with one or more embodiments of the present disclosure. FIG. 10 shows certain cross-sectional images of cardiac anatomy and certain devices associated with the process 900 of FIG. 9 to illustrate aspects of the process 900 according to one or more implementations thereof.

At block 902, the process 900 involves advancing a delivery catheter 40 to a coronary sinus 16 of a heart of a patient via a transcatheter access path. As described above, various access pathways may be utilized for maneuvering catheters (and associated guidewires) in and around the heart to deploy fluid bypass conduit device in accordance with embodiments of the present disclosure. For instance, access may be from above via either the subclavian or jugular veins into the superior vena cava 19, right atrium 5, and from there into the coronary sinus 16. Alternatively, the access path may start in the femoral vein and through the inferior vena cava 29 into the heart. Other access routes may also be used, some of which advantageously utilize a percutaneous incision through which the catheter 40 are inserted into the vasculature, normally through a sealed introducer, and from there the physician can control and navigate the distal end(s) of the devices from outside the body. The delivery catheter 40 can be advanced into the coronary sinus 16 through the coronary sinus ostium 66.

At block 904, the process 900 involves advancing the delivery catheter 40 through a wall 67 separating the coronary sinus 16 from the left atrium 2. The delivery catheter 40 may function to form and prepare the opening in the wall 67 of the left atrium, wherein a separate placement or delivery catheter is used for delivery of the fluid bypass conduit device. Alternatively, the deployment catheter 40 may be used as the both the puncture preparation and fluid bypass conduit device placement catheter.

Since the coronary sinus is largely contiguous around the left atrium, there are a variety of possible acceptable placements for the opening 65 in the wall 67. The site selected for the opening 65 may be made in an area where the tissue of the particular patient is less thick or less dense, as determined beforehand by non-invasive diagnostic means, such as a CT scan or radiographic technique, such as fluoroscopy or intravascular coronary echo (IVUS).

At block 906, the process 900 involves anchoring a first end of the fluid bypass conduit device transported in the catheter 40 in a target pulmonary vein 26 and/or associated ostium 25. The process 900 may involve deploying a distal end of the bypass fluid conduit device from the delivery catheter 40 for anchoring thereof. The conduit device 80 can comprise a generally tubular body or sleeve defining a lumen. The distal end of the conduit device 80 may serve as a fluid inlet. The distal end of the conduit device 80 may be associated with one or more anchoring features 81, which may be used to anchor the conduit device 80 to the pulmonary vein 26. The anchor feature(s) 81 may comprise, for example, one or more barb- or corkscrew-type tissue anchors and/or a stent form for anchoring to and/or in the pulmonary vein 26. Anchoring the distal end of the bypass fluid conduit 80 to the pulmonary vein 26 may involve embedding one or more barb tissue anchors associated with the distal end of the bypass fluid conduit 80 into biological tissue associated with the pulmonary vein 26. In some implementations, the process involves anchoring the distal end of the bypass fluid conduit 80 to another pulmonary vein using an anchor coupled to the anchor feature(s) 81 by an arm or clip member.

The bypass fluid conduit device 80 may be implanted at or in the pulmonary vein 26, 25 in such a way as to effectively fluid-seal the target pulmonary vein. Alternatively, the distal end of the conduit device 80 may be implanted or anchored at the pulmonary vein or pulmonary vein ostium in such a way as to include gaps or spaces around a periphery of the conduit device 80 through which blood may flow. Such gaps or spaces may be intentionally and/or deliberately allowed or implemented, or may result naturally from imperfect sealing or anchoring of the conduit device 80. Although the process 900 is described as involving first implanting the conduit device 80 in the pulmonary vein and secondly implanting the proximal end of the device 80 in the wall 67 between the left atrium 2 and the coronary sinus 16. in some implementations, the fluid bypass conduit device 80 may first be anchored to the wall 67, after which one or more of the pulmonary veins may be identified as providing a desired or ideal output or reduction in pressure, and such identified vein(s) may be coupled to the conduit device 80.

In some embodiments, the target pulmonary vein 26 may be selected to optimize an amount of blood flow shunted from the left side of the heart to the right. For example, the process 900 may involve selecting a desired one or number of pulmonary veins designed to provide the desired portion of the inlet blood flow from the lungs through the bypass conduit device 90.

At block 908, the process 900 involves withdrawing the delivery catheter 40 back to and/or through the wall 67 separating the coronary sinus 16 and left atrium 2, thereby deploying a medial channel portion of the fluid bypass conduit 80 and exposing the same in the left atrium 2. The bypass conduit device 80 may advantageously be at least partially self-expanding, and may include a jacket or cover, which may comprise thin PTEF material or similar, or biological tissue. The medial portion of the conduit device 80 can comprise an at least partially rigid frame, which may comprise an expandable laser-cut metal frame and/or one or more annular hoops covered by a sleeve or covering. The medial portion of the conduit device 80 may advantageously be at least partially flexible and may be pre-formed into a desired (e.g., at least partially curved) shape. The conduit device 80 can be advanced from the delivery catheter by pushing the conduit device 80 out of the delivery catheter 80 and/or retracting the delivery catheter 40 relative to the conduit device 80. In some implementations, a pusher device extending axially through at least a portion of the delivery catheter 40 may be used to assist in deploying the conduit device 80 from the catheter.

At block 910, the process 900 involves anchoring a proximal end of the fluid bypass conduit device 80 to the wall 67 between the atrium 2 and coronary sinus 16, such that the internal fluid channel of the conduit 80 provides a pathway from the pulmonary vein 26 through the wall 67 and into the right atrium 5. The anchor feature(s) 82 associated with the proximal end of the conduit device 80 may be any type of anchor features, including expanding coils or arms, or barb-type anchors configured to embed in the tissue of the wall 67. Anchoring the proximal end of the bypass fluid conduit 80 to the wall 67 separating the coronary sinus from the left atrium may comprise expanding a wire coil anchor associated with the proximal end of the bypass fluid conduit 80, the wire coil having a diameter that is greater than a diameter of the opening 65 in the wall 67 separating the coronary sinus 16 from the left atrium 2.

At block 912, the process 900 involves withdrawing the delivery catheter 40 from the heart of the patient, thereby leaving the fluid bypass implant device 80 implanted as shown in image 911. Due to the generally higher-pressure state in the left side of the heart compared to the right side of the heart, fluid back flow from the right atrium 5 to the left side of the heart may generally not occur in the steady-state implanted condition. With the delivery catheter withdrawn, the fluid bypass conduit device 80 can advantageously provide shunting from the left side of the heart to the right side of the heart, as described above. For example, the process 900 may further involve channeling blood from the pulmonary vein 26 to the coronary sinus 16 through the bypass fluid conduit 80.

As described in detail above, fluid bypass conduit devices in accordance with embodiments of the present disclosure may provide fluid coupling through the interatrial septum, which may provide a convenient location for conduit anchoring in view of the adjacency of the atria and the familiarity of transseptal access processes. However, there is generally a possibility of emboli travelling from the right side of the heart to the left, which presents a stroke risk. Such events generally only happen if the right atrium pressures go above left atrium pressures, such as during discrete events like coughing, sneezing, Valsalva maneuver, or bowel movements. The anatomical position of the septum would naturally allow emboli to travel between the right atrium and the pulmonary vein(s) was if the pressure gradient flips. This can be mitigated by a valve or filter element in the conduit device, but there may still be a risk that emboli will cross over.

Fluid coupling through the coronary sinus can offer certain benefits. For example, the coronary sinus can be much less likely to have emboli present for various reasons. First, the blood draining from the coronary vasculature into the right atrium has generally just passed through capillaries, so it is essentially filtered blood. Second, the ostium of the coronary sinus in the right atrium is often partially covered by a pseudo-valve called the Thebesian Valve. The Thebesian Valve is not always present, but some studies show it is present in >60% of hearts and can act as a natural filter to the coronary sinus to prevent emboli from entering in the event of a spike in right atrium pressure. Third, the pressure gradient between the coronary sinus and the right atrium into which it drains is generally very low, meaning that emboli in the right atrium is likely to remain there. Fourth, in the event that emboli do enter the coronary sinus, there is generally a much greater gradient between the right atrium and the coronary vasculature than between the right atrium and the left atrium. Most likely emboli would travel further down the coronary vasculature until right atrium pressure returned to normal and then the emboli would return directly to the right atrium.