System for delivering a device for regulating blood pressure across the interatrial septum - Patent application

Abstract

A system for delivering an interatrial shunt device to a puncture in a patient's atrial septum is provided. The delivery device described herein does not require a separate dilator, as its components function as a dilator to enlarge the puncture in the atrial septum prior to delivery of the interatrial shunt. The integrated dilator may include an expandable portion that transitions to a contracted state after dilation of the puncture for deployment of the shunt. Alternatively, the delivery sheath may have an expandable portion that forms part of the dilator, whereby the sheath may be expanded to allow deployment of the shunt. A balloon catheter may be used to expand the sheath. Alternatively, a portion of the shunt device may form part of the dilator prior to deployment of the shunt.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Patent Application No. 63 / 263,535, filed November 4, 2021, the entire contents of which are incorporated herein by reference.

[0002] (Technical field) The present application relates generally to devices and methods for delivering an implantable device to the interatrial septum, particularly in subjects suffering from cardiac pathologies such as pulmonary arterial hypertension (PAH), congestive heart failure (CHF), or myocardial infarction (MI). [Background technology]

[0003] Pulmonary arterial hypertension (PAH) occurs when pressure in the blood vessels and lungs becomes too high. PAH can be caused by blockages in the arteries in the lungs, such as the development of scar tissue in the blood vessels of the lungs, but in many cases, the cause is unknown. Under normal conditions, the pressure in the blood vessels of the right side of the heart and the lungs is lower than the rest of the body, which maximizes oxygenation of the blood in the lungs. With PAH, the heart must work harder under higher pressure to pump blood through the arteries in the lungs, weakening the heart muscle over time. As a result, the heart may not pump enough blood to the lungs, where it should be oxygenated to keep the body functioning normally.

[0004] Heart failure is a physiological state in which cardiac output is insufficient to meet the body's needs or meets them only at higher filling pressures. There are many underlying causes of HF, including myocardial infarction, coronary artery disease, valvular disease, hypertension, and myocarditis. Chronic heart failure is associated with alterations in neurohormonal activation and autonomic regulation. Although these compensatory neurohormonal mechanisms provide beneficial support for the heart under normal physiological circumstances, they also play a fundamental role in the development and subsequent progression of HF.

[0005] For example, one of the body's main compensatory mechanisms for reduced blood flow in HF is to increase the amount of salt and water retained by the kidneys. Retaining salt and water, instead of excreting it via urine, increases the volume of blood in the bloodstream and helps maintain blood pressure. However, the larger blood volume also causes the myocardium, especially the ventricles, to become enlarged. As the ventricles become enlarged, wall thickness decreases and the heart's contractions become weaker, causing a negative spiral in cardiac function. Another compensatory mechanism is vasoconstriction of the arterial system, which increases blood pressure and helps maintain adequate perfusion, thus increasing the load the heart must pump against.

[0006] In low ejection fraction (EF) heart failure, high pressure in the heart results from the body's attempt to maintain the high pressure required for proper peripheral perfusion. However, as the heart weakens as a result of such high pressure, the disorder becomes worse. Pressure in the left atrium can exceed 25 mmHg, at which point fluid from the blood flowing through the pulmonary circulation seeps or flows out of the pulmonary capillaries, into the pulmonary interstitial spaces, and into the alveoli, causing pulmonary congestion and, if untreated, acute pulmonary edema syndrome and death.

[0007] Table 1 lists typical ranges of right atrial pressure (RAP), right ventricular pressure (RVP), left atrial pressure (LAP), left ventricular pressure (LVP), cardiac output (CO), and stroke volume (SV) for normal hearts and hearts with HF. In a normal heart beating at about 70 beats per minute, the stroke volume required to maintain normal cardiac output is about 60-100 milliliters. When cardiac preload, afterload, and contractility are normal, the pressures required to achieve normal cardiac output are listed in Table 1. In hearts with HF, hemodynamic parameters change (as shown in Table 1) to maintain peripheral perfusion. [Table 1]

[0008] HF is generally classified as either systolic heart failure (SHF) or diastolic heart failure (DHF). In SHF, the pumping action of the heart is reduced or weakened. A common clinical measurement is the ejection fraction, which is the volume of blood ejected out of the left ventricle (stroke volume) divided by the maximum volume inside the left ventricle at the end of diastole or relaxation. A normal ejection fraction is greater than 50%. Systolic heart failure generally causes a reduced ejection fraction of less than 40%. Such patients have heart failure with reduced ejection fraction (HFrEF). Patients with HFrEF may have a larger left ventricle, usually due to a phenomenon called "cardiac remodeling" that occurs secondary to higher ventricular pressures.

[0009] In DHF, the heart generally contracts normally, with a normal ejection fraction, but is stiffer or less compliant than a healthy heart would be when relaxed and filling with blood. Such patients are considered to have heart failure with preserved ejection fraction (HFpEF). This stiffness can prevent blood from filling the heart and cause congestion in the lungs, which can lead to pulmonary venous hypertension and pulmonary edema. HFpEF is more common in patients over 75 years of age, especially women who suffer from hypertension.

[0010] Both variants of HF are treated using pharmacological approaches, which typically involve the use of vasodilators to reduce cardiac workload by reducing systemic vascular resistance, and diuretics to prevent fluid accumulation and edema formation and reduce cardiac filling pressures. Although no pharmacological therapy has been shown to improve morbidity or mortality in HFpEF, several classes of drugs, including renin-angiotensin antagonists, beta-blockers, and mineralocorticoid antagonists, have had a significant impact on the management of patients with HFrEF. Nevertheless, in general, HF remains a progressive disease, with most patients experiencing deterioration in cardiac function and symptoms over time. In the United States, more than one million people annually develop acute HF and are hospitalized, with a mortality rate higher than most forms of cancer.

[0011] In more severe cases of HFrEF, assist devices such as mechanical pumps are used to reduce the load on the heart by performing all or part of the pumping function normally performed by the heart. Chronic left ventricular assist devices (LVADs) and heart transplants are often used as measures of last resort. However, such assist devices are typically intended to improve the heart's pumping capacity, increase cardiac output to a level comparable to normal life, and support the patient until a donor heart is available for transplantation. Although such mechanical devices allow the propulsion of significant volumes of blood (liters / minute), they are limited by the need for a power source, a relatively large pump, and pose the risk of hemolysis, thrombus formation, and infection. Temporary assist devices, intra-aortic balloons, and pacing devices are also used.

[0012] Various devices have been developed to modify blood pressure and flow within a given vessel or between ventricles using stents. Implantable interatrial shunt devices have been successfully used in patients with severe symptomatic heart failure. By diverting or shunting blood from the left atrium (LA) to the right atrium (RA), pressure within the LA is lowered or prevented from rising as high as it would otherwise (left atrial decompression). Such an outcome would be expected to prevent, alleviate, or limit symptoms, signs, and syndromes associated with pulmonary congestion. These include severe shortness of breath, pulmonary edema, hypoxia, the need for emergency hospitalization, mechanical ventilation, and death.

[0013] Percutaneous implantation of an interatrial shunt generally requires transseptal catheter placement immediately prior to shunt device insertion. The transseptal catheter placement system is placed from an entry site in the femoral vein across the interatrial septum in the region of the fossa ovalis (FO), the central and thinnest region of the interatrial septum. This is the same general location where a congenital ostium secundum atrial septal defect (ASD) would be located. The FO in adults is typically 15-20 mm in its major axial dimension and ≦3 mm in thickness, but in some circumstances may be up to 10 mm thick. LA ventricular access may be achieved using many different techniques familiar to those skilled in the art, including, but not limited to, needle puncture, stylet puncture, screw needle puncture, and radiofrequency ablation. The passage between the two atria is dilated to facilitate passage of a shunt device with the desired orifice size. Dilation is generally accomplished by advancing a tapered sheath / dilator catheter system or by inflation of an angioplasty type balloon across the FO. A limitation of advancing a typical separate tapered dilator is that after dilating the septum, the dilator must be removed from the sheath before any devices to be delivered can be loaded into the sheath and advanced for deployment.

[0014] Devices such as those described in U.S. Pat. No. 5,312,341 to Turi have also been theorized for transseptal catheter placement. Specifically, these devices have a retention means, such as an inflatable balloon, that is inflated within the patient's left atrium to prevent inadvertent retraction of the distal tip of the sheath from the left atrium during the subsequent portion of the catheter placement procedure.

[0015] In view of the foregoing, it would be desirable to provide a device for delivering an implantable device to the interatrial septum of the heart to reduce left atrial pressure while reducing the number of delivery tools required.

[0016] It would further be desirable to provide devices and methods for controlled positioning and delivery of atrial shunt devices. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] U.S. Patent Application Serial No. 5,312,341 Summary of the Invention [Means for solving the problem]

[0018] The present disclosure overcomes the shortcomings of known systems and methods by providing a system and method for delivering a shunt to the atrial septum of a patient. For example, the device may include a sheath having a proximal region, a distal region, and a sheath lumen extending therethrough, the sheath lumen being sized and shaped to receive the shunt in a collapsed delivery state, and a balloon catheter configured to be movably disposed within the sheath lumen. The balloon catheter may include a balloon configured to transition between a pursed collapsed state adjacent the distal region and an inflated expanded state to form a continuous step-free transition between the balloon and the distal region of the sheath. The device may further include a handle having one or more actuators configured to be actuated to deploy the shunt in the atrial septum.

[0019] In addition, the device may include a pusher slidably disposed within the sheath lumen. The pusher may be operatively coupled to a pusher actuator of the one or more actuators of the handle such that the pusher actuator may be configured to be actuated to move the pusher within the sheath lumen. For example, the pusher actuator may be configured to be actuated to move the pusher distally relative to the sheath such that a distal end of the pusher engages a proximal portion of the shunt in the collapsed delivery state, thereby moving the shunt distally relative to the sheath until a distal portion of the shunt is exposed beyond a distal region of the sheath and transitions from the collapsed delivery state to an expanded deployed state.

[0020] The device further includes a release knot slidably disposed within the sheath lumen, where the release knot may be configured to be releasably engaged with the shunt, e.g., at a proximal portion of the shunt, via a hitch knot, e.g., a Painter hitch knot, or a Quick Tie and Release (QTaR) hitch knot. For example, a first end of the release knot may be operatively coupled to a release actuator of the one or more actuators of the handle, and a second end of the release knot may be operatively coupled to a retrieval actuator of the one or more actuators of the handle, whereby actuation of the release actuator causes the hitch knot to break apart and disengage the release knot from the shunt, and actuation of the retrieval actuator causes retraction of the shunt proximally within the sheath lumen via the hitch knot for retrieval partway through the shunt. Alternatively, a first end of the release knot may be operatively coupled to a release actuator of one or more actuators of the handle and a second end of the release knot may be operatively coupled to a distal portion of the pusher, whereby actuation of the release actuator causes the hitch knot to break apart and disengage the release knot from the shunt, and actuation of the pusher actuator causes retraction of the shunt proximally within the sheath lumen through the hitch knot for partial retrieval of the shunt.

[0021] Further, the balloon can be configured to be deflated to allow deployment of the shunt through the distal region of the sheath. The balloon catheter can include a fluid lumen configured to fluidly couple the balloon and a fluid source. Additionally, the balloon catheter can be operatively coupled to a balloon catheter actuator of the one or more actuators of the handle such that actuation of the balloon catheter actuator moves the balloon catheter relative to the sheath.

[0022] According to another aspect of the present disclosure, a method of delivering a shunt to a patient's atrial septum is provided, which may include inflating a balloon adjacent a distal region of a sheath to form a continuous, step-free transition between the balloon and the distal region of the sheath, the balloon being disposed on a distal portion of a balloon catheter slidably disposed within a lumen of the sheath, delivering the inflated balloon and sheath through an opening in the atrial septum such that the inflated balloon and sheath dilate the opening in the atrial septum, deflating the balloon, advancing the shunt distally within the lumen of the sheath in a collapsed delivery state until a distal portion of the shunt is exposed beyond the distal region of the sheath and transitions to an expanded, deployed state in a first atrium, and retracting the sheath proximally relative to the atrial septum until a proximal portion of the shunt is exposed beyond the distal region of the sheath and transitions to an expanded, deployed state in a second atrium such that the shunt is deployed in the atrial septum.

[0023] The shunt may be releasably engaged with the release knot such that pulling a first end of the release knot disengages the release knot from the shunt and pulling a second end of the release knot causes retraction of the shunt proximally within the lumen of the sheath for retrieval of the shunt midway. For example, the release knot may be releasably engaged with the shunt via a Painta hitch knot or a Quick Tie and Release (QTaR) hitch knot.

[0024] Thus, prior to retracting the sheath proximally relative to the atrial septum until the proximal portion of the shunt is exposed beyond the distal region of the sheath, the method may further include pulling a first end of the release knot to disengage the release knot from the shunt. Additionally, prior to retracting the sheath proximally relative to the atrial septum until the proximal portion of the shunt is exposed beyond the distal region of the sheath, the method may further include pulling a second end of the release knot to transition a distal portion of the shunt to a folded delivery state within the lumen of the sheath for partial retrieval of the shunt. Additionally, prior to retracting the sheath proximally relative to the atrial septum until the proximal portion of the shunt is exposed beyond the distal region of the sheath, the method may further include retracting the sheath and the shunt proximally relative to the atrial septum from within the first atrium until the distal portion of the shunt contacts the atrial septum.

[0025] Advancing the shunt distally within the lumen of the sheath may include advancing a pusher distally within the lumen of the sheath such that a distal end of the pusher engages a proximal portion of the shunt in the collapsed delivery state within the lumen of the sheath. Thus, prior to retracting the sheath proximally relative to the atrial septum, the method may further include retracting the shunt proximally within the lumen of the sheath until the proximal portion of the shunt is exposed beyond a distal region of the sheath, and transitioning the distal portion of the shunt to the collapsed delivery state within the lumen of the sheath for mid-way retrieval of the shunt. In some embodiments, prior to retracting the shunt proximally within the lumen of the sheath, the method may include retracting the pusher distally relative to the sheath. Prior to advancing the shunt within the lumen of the sheath, the method may further include retracting the balloon catheter and the pursed balloon proximally within the lumen of the sheath to a location proximal to the shunt in the collapsed delivery state. In addition, the method may include removing the sheath and the balloon catheter from the patient.

[0026] According to another aspect of the present disclosure, another device for delivering a shunt to a patient's atrial septum is provided. The device may include a sheath configured to be advanced through a hole in the atrial septum, the sheath having a proximal region, a distal region, and a sheath lumen extending therethrough, the sheath lumen being sized and shaped to receive the shunt in a collapsed delivery state, and a dilator movably disposed within the sheath lumen. The dilator may include an expandable portion configured to transition between a first state and a second state in which the expandable portion engages a distal region of the sheath. Thus, the dilator and sheath may be configured such that, as the device is advanced through the hole in the atrial septum, the tissue surrounding the hole is smoothly guided over the distal portion of the dilator and the sheath to dilate the hole in the atrial septum. The dilator may include a guidewire lumen sized and shaped to receive a guidewire.

[0027] According to one aspect of the disclosure, the dilator may further include a dilation catheter movably disposed within the sheath lumen and a conical tip coupled to a distal end of the dilation catheter and to a distal portion of the expandable portion of the dilator. For example, in a first state, a proximal portion of the expandable portion may be radially contracted inwardly toward the dilation catheter, and in a second state, the proximal portion of the expandable portion may be removably engaged with a distal region of the sheath to form a continuous stepless transition between the sheath and the expandable portion of the dilator. The dilation catheter may be configured to be moved distally relative to the sheath to transition the expandable portion of the dilator from the second state to the first state. Additionally, the expandable portion of the dilator may be biased toward the first state.

[0028] In the second state, the distal portion of the expandable portion of the dilator may engage with the outer surface of the distal region of the sheath. Thus, the device may have a continuous step-free transition between the sheath and the expandable portion of the dilator when the expandable portion is in the second state. The guidewire lumen may extend through the conical tip and the dilation catheter. In addition, the sheath may be configured such that the expandable portion of the dilator is moved proximally relative to the dilator when in the first state and deploys the shunt in the atrial septum. The device may further include a hollow catheter, e.g., a PEEK tube, movably disposed within the sheath lumen, the hollow catheter being sized and shaped to receive the dilation catheter. For example, in the first state, the proximal portion of the expandable portion of the dilator may be disposed within the distal region of the hollow catheter.

[0029] According to another aspect of the present disclosure, the distal region of the sheath may be configured to transition between a contracted state and an expanded state, and the expandable portion of the expander may include a proximal portion coupled to an outer tube movably disposed within the sheath lumen and a conical distal portion coupled to an inner tube movably disposed within the outer tube, whereby the conical distal portion is movable relative to the proximal portion between a second state in which the distal region of the sheath is sandwiched between the proximal portion and the conical distal portion in the contracted state, and a first state in which the distal region of the sheath disengages from the proximal portion and the conical distal portion and transitions to the expanded state. Thus, the device may have a continuous, stepless transition between the conical distal portion and the distal region of the sheath when the distal region of the sheath is in the contracted state.

[0030] In the contracted state, the distal region of the sheath may have a plurality of longitudinal slits disposed circumferentially along the distal region and extending from a distal end of the distal region toward the proximal region of the sheath. Furthermore, in the expanded state, the distal region of the sheath may be expanded along the plurality of longitudinal slits such that each of the plurality of longitudinal slits comprises a V-shape. The distal region of the sheath may be biased toward the expanded state. Furthermore, the distal region of the sheath may include an elastic material encapsulated with a biocompatible material. For example, the elastic material may be a superelastic nitinol and the biocompatible material may be a polyether block amide. A guidewire lumen may extend through the conical distal portion and the inner tube.

[0031] According to another aspect of the disclosure, the expandable portion of the expander includes an expandable braided tip coupled to an inner tube movably disposed within a sheath lumen, the expandable braided tip may be configured to transition between a first state and a second state. Additionally, the distal portion of the shunt may be configured to transition between a collapsed delivery state, in which the distal portion of the shunt forms a continuous stepless transition between the distal portion of the shunt and the expandable braided tip, and an expanded deployed state when the expandable braided tip is in the second state. The proximal end of the expandable braided tip may be coupled to an outer tube, the distal end of the expandable braided tip may be coupled to an inner tube, and the inner tube may be movably disposed within the lumen of the outer tube such that the proximal end of the expandable braided tip is movable relative to the distal end of the expandable braided tip to transition the expandable braided tip between the first state and the second state. Additionally, the distal portion of the shunt may be configured to transition from the collapsed delivery state to the expanded deployed state upon application of heat. Thus, the sheath may further include a fluid lumen configured to deliver heated liquid to the distal portion of the shunt. The device may have a continuous, step-free transition between the distal portion of the shunt and a distal region of the sheath when the distal portion of the shunt is in the collapsed delivery state. A guidewire lumen may extend through the inner tube.

[0032] According to another aspect of the present disclosure, the distal region of the sheath may be configured to transition between a contracted state and an expanded state, and the expandable portion of the expander may include a balloon coupled to a balloon catheter configured to be movably disposed within the sheath lumen. The balloon may be configured to be inflated from a first state to a second state to transition the distal region from the contracted state to the expanded state. For example, in the contracted state, the distal region of the sheath may define an opening and may have a plurality of longitudinal slits disposed circumferentially along the distal region and extending from the opening toward the proximal region of the sheath, and in the expanded state, the distal region of the sheath may be expanded along the plurality of longitudinal slits such that each of the plurality of longitudinal slits comprises a V-shape. A distal tip of the balloon may be configured to extend through the opening and form a continuous step-free transition between the balloon and the distal region of the sheath. In addition, the plurality of longitudinal slits may define a plurality of fingers of the distal region, and a distal end of each of the plurality of fingers may have a rounded shape. Additionally, the distal region of the sheath may include a shape memory material configured to cause the distal region to return to a contracted state upon exposure to heat.

[0033] According to another aspect of the disclosure, the expandable portion of the expander may include a balloon coupled to a balloon catheter configured to be movably disposed within the sheath lumen. The balloon may be configured to transition between a first state and a second state adjacent the distal region to form a continuous step-free transition between the balloon and the distal region of the sheath. The device may further include a pusher slidably disposed within the sheath lumen. The pusher may have a pusher lumen sized and shaped to slidably receive the balloon catheter therethrough and a distal end configured to engage a proximal portion of the shunt in the collapsed delivery state, thereby moving the shunt distally relative to the sheath. The device may further include a release knot slidably disposed within the sheath lumen. For example, the release knot can be configured to be releasably engaged to the shunt via a hitch knot, e.g., a Painta hitch knot, or a Quick Tie and Release (QTaR) hitch knot, such that pulling a first end of the release knot disengages the release knot from the shunt and pulling a second end of the release knot causes retraction of the shunt proximally within the sheath lumen for retrieval of the shunt partway through.

[0034] In some embodiments, the release knot may be configured to be releasably engaged with the proximal portion of the shunt. Additionally, the first and second ends of the release knot may pass through the central passage of the shunt toward the intermediate portion of the shunt, loop around an outer surface of the intermediate portion of the shunt, and return toward the hitch knot, such that pulling the second end of the release knot transitions the shunt toward the collapsed delivery state. Alternatively, the release knot may be configured to be releasably engaged with the intermediate portion of the shunt, and the first and second ends of the release knot may loop around an outer surface of the intermediate portion of the shunt, such that pulling the second end of the release knot transitions the shunt toward the collapsed delivery state. The balloon may be configured to be puckered to allow deployment of the shunt through the distal region of the sheath. Additionally, the balloon catheter may have a fluid lumen configured to fluidly couple the balloon and a fluid source. [Brief description of the drawings]

[0035] [Figure 1-1] 1A-1D illustrate an exemplary device for delivering an interatrial shunt device to the atrial septum according to the present disclosure. [Figure 1-2] 1A-1D illustrate an exemplary device for delivering an interatrial shunt device to the atrial septum according to the present disclosure.

[0036] [Figure 2-1] 2A-2F illustrate an alternative exemplary device for delivering an interatrial shunt device to the atrial septum according to the present disclosure. [Figure 2-2] 2A-2F illustrate an alternative exemplary device for delivering an interatrial shunt device to the atrial septum according to the present disclosure. [Figure 2-3] 2A-2F illustrate an alternative exemplary device for delivering an interatrial shunt device to the atrial septum according to the present disclosure.

[0037] [Figure 3-1]3A-3G illustrate another alternative exemplary device for delivering an interatrial shunt device to the atrial septum according to the present disclosure. [Figure 3-2] 3A-3G illustrate another alternative exemplary device for delivering an interatrial shunt device to the atrial septum according to the present disclosure. [Figure 3-3] 3A-3G illustrate another alternative exemplary device for delivering an interatrial shunt device to the atrial septum according to the present disclosure.

[0038] [Figure 4A] 4A and 4B illustrate yet another alternative exemplary device for delivering an interatrial shunt device to the atrial septum in accordance with the present disclosure. [Figure 4B] 4A and 4B illustrate yet another alternative exemplary device for delivering an interatrial shunt device to the atrial septum in accordance with the present disclosure.

[0039] [Figure 5A] FIG. 5A illustrates yet another alternative exemplary device for delivering an interatrial shunt device to the atrial septum according to the present disclosure.

[0040] [Figure 5B] FIG. 5B illustrates an exemplary handle for actuating the delivery device of FIG. 5A, constructed in accordance with the principles of the present disclosure.

[0041] [Figure 6A] FIG. 6A illustrates an exemplary knotting mechanism of the delivery device of FIG. 5A.

[0042] [Figure 6B] FIG. 6B illustrates an alternative exemplary knotting mechanism according to the principles of the present disclosure.

[0043] [Figure 7A] 7A-7H illustrate exemplary method steps for delivering an interatrial shunt device to the atrial septum using the delivery device of FIGS. 5A and 5B according to the present disclosure. [Figure 7B] 7A-7H illustrate exemplary method steps for delivering an interatrial shunt device to the atrial septum using the delivery device of FIGS. 5A and 5B according to the present disclosure. [Figure 7C] 7A-7H illustrate exemplary method steps for delivering an interatrial shunt device to the atrial septum using the delivery device of FIGS. 5A and 5B according to the present disclosure. [Figure 7D] 7A-7H illustrate exemplary method steps for delivering an interatrial shunt device to the atrial septum using the delivery device of FIGS. 5A and 5B according to the present disclosure. [Figure 7E] 7A-7H illustrate exemplary method steps for delivering an interatrial shunt device to the atrial septum using the delivery device of FIGS. 5A and 5B according to the present disclosure. [Figure 7F] 7A-7H illustrate exemplary method steps for delivering an interatrial shunt device to the atrial septum using the delivery device of FIGS. 5A and 5B according to the present disclosure. [Figure 7G] 7A-7H illustrate exemplary method steps for delivering an interatrial shunt device to the atrial septum using the delivery device of FIGS. 5A and 5B according to the present disclosure. [Figure 7H] 7A-7H illustrate exemplary method steps for delivering an interatrial shunt device to the atrial septum using the delivery device of FIGS. 5A and 5B according to the present disclosure.

[0044] [Figure 7I] 7I-7K illustrate exemplary method steps for partial retrieval of an inter-atrial shunt device using the delivery device of FIGS. 5A and 5B according to the present disclosure. [Figure 7J] 7I-7K illustrate exemplary method steps for partial retrieval of an inter-atrial shunt device using the delivery device of FIGS. 5A and 5B according to the present disclosure. [Figure 7K]7I-7K illustrate exemplary method steps for partial retrieval of an inter-atrial shunt device using the delivery device of FIGS. 5A and 5B according to the present disclosure.

[0045] [Figure 8A] 8A-8G illustrate example method steps for delivering an inter-atrial shunt device to the atrial septum using another example delivery device according to the present disclosure. [Figure 8B] 8A-8G illustrate example method steps for delivering an inter-atrial shunt device to the atrial septum using another example delivery device according to the present disclosure. [Figure 8C] 8A-8G illustrate example method steps for delivering an inter-atrial shunt device to the atrial septum using another example delivery device according to the present disclosure. [Figure 8D] 8A-8G illustrate example method steps for delivering an inter-atrial shunt device to the atrial septum using another example delivery device according to the present disclosure. [Figure 8E] 8A-8G illustrate example method steps for delivering an inter-atrial shunt device to the atrial septum using another example delivery device according to the present disclosure. [Figure 8F] 8A-8G illustrate example method steps for delivering an inter-atrial shunt device to the atrial septum using another example delivery device according to the present disclosure. [Figure 8G] 8A-8G illustrate example method steps for delivering an inter-atrial shunt device to the atrial septum using another example delivery device according to the present disclosure.

[0046] [Figure 8H] 8H and 81 illustrate exemplary method steps for partial retrieval of an inter-atrial shunt device using the delivery device of FIGS. 8A-8G according to the present disclosure. [Figure 8I]8H and 81 illustrate exemplary method steps for partial retrieval of an inter-atrial shunt device using the delivery device of FIGS. 8A-8G according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0047] The present invention is directed to a device for delivering an implantable device to a wall of the heart, such as the atrial septum, and thus may be useful in treating subjects suffering from heart failure, myocardial infarction, pulmonary hypertension, or other disorders associated with elevated atrial pressure. For example, the device of the present invention may be designed to deliver an hourglass or "diabolical" shaped shunt device, preferably formed from a shape memory metal, as described in U.S. Patent No. 9,629,715 to Nitzan, U.S. Patent No. 10,076,403 to Eigler, and U.S. Patent No. 11,458,287 to Eigler, each of which is assigned to the assignee of the present invention (the entire contents of each of which are incorporated herein by reference). The delivery device described herein is configured to securely anchor the shunt in a hole in the heart wall, such as the atrial septum, preferably the fossa ovalis, to function as an interatrial shunt and allow blood flow between the left and right atria.

[0048] 1A-1D, an exemplary delivery device 100 for delivering an interatrial shunt device 10 to the atrial septum is provided. As shown in FIG. 1A, the delivery device 100 includes a sheath 110 removably coupled to a dilator 103. The sheath 110 has a lumen extending from a distal region 112 of the sheath 110 to a proximal region of the sheath outside the patient. The lumen of the sheath 110 is sized and shaped to receive the shunt 10 in its collapsed delivery state. As shown in FIG. 1A, the distal region 112 of the sheath 110 can have an outer diameter that is less than the outer diameter of the remainder of the length of the sheath 110 extending from the distal region 112 toward the proximal region of the sheath 110.

[0049] The dilator 103 includes a dilatation catheter 102 movably disposed within the lumen of the sheath 110, which can be moved relative to the sheath 110, for example, via actuation of a patient-external handle, which is independently coupled to the sheath 110 and the dilatation catheter 102. In addition, the dilator 103 includes a dilator tip 104 coupled to the distal end of the dilatation catheter 102. The dilator tip 104 can be a soft tip with a low durometer hardness and can have an atraumatic conical shape that can be inserted through the atrial septum puncture to enlarge the puncture without damaging the surrounding tissue. Alternatively, the dilator tip 104 can have a sharp needle tip that can be used to create a puncture in the atrial septum, whereby further advancement of the dilator tip 104 across the atrial septum enlarges the puncture.

[0050] The dilator 103 may have a guidewire lumen 106 sized and shaped to receive a guidewire therethrough, such that the device 100 may be advanced over a conventional guidewire across the atrial septum. Thus, the guidewire lumen 106 may extend through the dilator tip 104 and the dilation catheter 102. Additionally, the dilator 103 may include an expandable portion 108. The expandable portion 108 may be coupled to the dilator tip 104 at its distal portion and extend toward the sheath 110. In one embodiment, the dilator tip 104 and the expandable portion 108 are formed from a unitary structure. As shown in FIG. 1D, at least the expandable portion 108 of the dilator 103 may be encapsulated with a biocompatible material 109, for example, a polyether block amide (PEBA), such as PEBAX® (available by Arkema, Colombes, France).

[0051] The expandable portion 108 may be formed from an elastic material, such as superelastic Nitinol, and may be transitionable between an expanded state and a contracted state. For example, the expandable portion 108 may be heat set during manufacturing in a contracted state such that the expandable portion 108 is biased toward the contracted state. Thus, prior to insertion into a patient, the expandable portion 108 may be expanded and fitted over the distal region 112 of the sheath 110. Specifically, as shown in FIG. 1A, in the expanded state, a proximal portion of the expandable portion 108 may be engaged with an outer surface of the distal region 112, thereby forming a step-free transition between the sheath 110 and the expandable portion 108 of the expander 103 when the expandable portion 108 is in the expanded state. Thus, when the proximal portion of the expandable portion 108 is engaged with the outer surface of the distal region 112 of the sheath 110, the proximal portion of the expandable portion 108 has the same outer diameter as the portion of the sheath 110 adjacent the distal region 112. A step-free transition between the sheath 110 and the expandable portion 108 results from the distal region 112 having an outer diameter that is less than the outer diameter of the remainder of the sheath 110. Although FIG. 1A illustrates the sheath 110 having a constant thickness along its longitudinal length (e.g., including the distal region 112) and thus an inner diameter that varies from the sheath 110 to the distal region 112, alternatively, the sheath 110 and the distal region 112 can have a constant inner diameter along their longitudinal lengths.

[0052] 1A, the device 100 may include a hollow catheter 114, e.g., a PEEK tube, movably disposed within a lumen of a sheath 110. The hollow catheter 114 may be sized and shaped to receive the dilatation catheter 102 and at least a portion of the proximal portion of the expandable portion 108 therethrough. Thus, the dilatation catheter 102, the hollow catheter 114, the shunt 10 in its collapsed delivery state, and the sheath 110 may be concentric. Each of the dilatation catheter 102, the hollow catheter 114, and the sheath 110 may be coupled at their proximal regions to a handle for use by a clinician such that each component may be independently actuated via the handle.

[0053] 1B, upon movement of the dilator 103 distally relative to the sheath 110, the expandable portion 108 of the dilator 103 will disengage from the distal region 112 of the sheath 110 and return to its contracted state, since the distal region 112 will no longer exert a radially outward force against the inner surface of the proximal portion of the expandable portion 108. Thus, the expandable portion 108 will be forced to contract radially inward toward the dilation catheter 102. In its contracted state, the proximal portion of the expandable portion 108 may be adjacent to an opening into the hollow catheter 114. Thus, upon retraction of the dilation catheter 102 relative to the hollow catheter 114, at least a portion of the proximal portion of the expandable portion 108 may be received by the distal region of the hollow catheter 114, thereby causing the expandable portion 108 to contract even further. The shunt 10 may be deployed by retracting the sheath 110 proximally relative to the hollow catheter 114 and dilator 103, as shown in FIG. 1C, thereby implanting the shunt 10 in the atrial septum AS.

[0054] For example, loading of the shunt 10 into the delivery device 100 during manufacture, or in a preparation step, may proceed as follows: First, the hollow catheter 114 may be advanced over the dilatation catheter 102 until a distal region of the hollow tube 114 is adjacent the expandable portion 108 of the dilator 103. The hollow catheter 114 may be further advanced over at least a portion of the proximal portion of the expandable portion 108 to receive the proximal portion of the expandable portion 108 therein, providing rigidity to the combined structure of the hollow catheter 114 and the dilator 103. The hollow catheter 114 and the dilator 103 may be advanced distally through the lumen of the sheath 110 until at least the dilator 103 is exposed beyond the proximal region 112 of the sheath 110, such that together the dilatation catheter 102, the hollow catheter 114, the shunt 10 in its collapsed delivery state, and the sheath 110 are concentric. Alternatively, the combined structure of hollow catheter 114 and dilator 103 can be loaded back through the distal opening of sheath 110 until dilator 103 is adjacent distal region 112 .

[0055] The dilatation catheter 102 may then be moved distally relative to the hollow catheter 114 such that the expandable portion 108 is no longer within the hollow catheter 114 but is expanded radially outwardly away from the dilatation catheter 102 and may be positioned over the outer surface of the distal region 112 of the sheath 110. Upon release of the expandable portion 108 over the distal region 112, the distal region 112 will maintain the expandable portion 108 in its expanded state such that a proximal portion of the expandable portion 108 fits over the distal region 112. Thus, the sheath 110, the expandable portion 108, and the tip 104 form a smooth, continuous dilator assembly as shown in FIG. 1A that is suitable for insertion into a blood vessel over a guidewire and advancement across the interatrial septum.

[0056] The shunt 10 may then be folded into its folded delivery state within the sheath 110 using a tool such as described, for example, in U.S. Pat. No. 9,713,696 to Yacoby or U.S. Patent Application Publication No. 2020 / 0315599 to Nae, each of which is assigned to the assignee of the present invention, the entire contents of each of which are incorporated herein by reference. The delivery device 100 is then ready to deliver the shunt 10. Delivery of the shunt 10 using the delivery device 100 described above may proceed as follows: A guidewire 101 may be advanced to a target location, for example, through an atrial septal puncture in the left atrium of the patient. The device 100 may be advanced over the guidewire 101 via the guidewire lumen 106 until the dilator tip 104 contacts the atrial septal puncture. The device 100 can be advanced further, causing the dilator 103 to enlarge the atrial septal puncture as the tissue surrounding the puncture is smoothly guided over the dilator tip 104 and then over the expandable portion 108 and sheath 110. Unlike other known delivery systems, a separate dilator (which must be subsequently removed prior to loading the shunt into the sheath 110) is not required to enlarge the atrial septal puncture.

[0057] Under visualization methods such as fluoroscopy and / or ultrasound imaging such as transesophageal echo (TEE) or intracardiac echo (ICE), the target location of device 100 relative to the atrial septum may be verified, for example, via radiopaque markers on the sheath 110. Next, the dilatation catheter 102 may be moved distally relative to the sheath 110, as shown in FIG. 1B, thereby causing the expandable portion 108, for example, due to its superelasticity, to disengage from the distal region 112 and transition from its expanded state to its contracted state toward the dilatation catheter 102. The dilatation catheter 102 may then be moved proximally relative to the hollow catheter 114, such that at least a portion of the proximal portion of the expandable portion 108 is received within the hollow catheter 114. While the hollow catheter 114, dilator 103, and shunt 10 remain stationary against the atrial septum, the sheath 110 can be retracted proximally to expose a distal portion of the shunt 10, which then deploys within the left atrium. The shunt 10 can be maintained stationary against the atrial septum using a device within the sheath 110, such as those described in WO2020202046, the entire contents of which are incorporated herein by reference. For example, a device having multiple hooks can be used to engage the proximal portion of the shunt 10 within the sheath 110.

[0058] After the distal portion of the shunt 10 has been deployed within the left atrium, the delivery device 100 may be retracted proximally until the distal portion of the shunt 10 contacts the atrial septal wall. The sheath 110 may then be further retracted proximally while the shunt 10 is held stationary against the atrial septum until the proximal portion of the shunt 10 is exposed from the distal region 112 of the sheath 110 and deployed within the patient's right atrium, as shown in FIG. 1C. The delivery device 100 may then be removed from the patient, leaving the shunt 10 implanted in the atrial septum.

[0059] 2A-2F, an exemplary delivery device 200 for delivering the interatrial shunt device 10 to the atrial septum is provided. As shown in FIGS. 2A and 2D, the delivery device 200 includes a sheath 212 removably coupled to a dilator 203. The dilator 203 includes a proximal portion 208 coupled to an outer tube 210 and a distal portion 204 coupled to an inner tube 202 movably disposed within the outer tube 210. The dilator 203 may be expandable such that the proximal portion 208 may be moved relative to the distal portion 204 via, for example, actuation of a patient-external handle independently coupled to the outer tube 210 and the inner tube 202. As shown in FIG. 2A, the proximal surface of the distal portion 204 may have a geometry corresponding to the distal surface of the proximal portion 208. For example, the distal portion 204 may have an arrowhead shape.

[0060] The distal portion 204 may be a soft tip with a low durometer hardness and may have an atraumatic cone shape that may be inserted through a puncture in the atrial septum to enlarge the puncture without damaging the surrounding tissue. Alternatively, the distal portion 204 may have a sharp needle tip that may be used to create a puncture in the atrial septum such that further advancement of the distal portion 204 across the atrial septum will enlarge the puncture. The dilator 203 may have a guidewire lumen 206 that is sized and shaped to receive a guidewire therethrough, such that the device 200 may be advanced over a conventional guidewire across the atrial septum. Thus, the guidewire lumen 206 may extend through the distal portion 204 and the inner tube 202.

[0061] The sheath 212 has a lumen extending from a distal region 214 of the sheath 212 to a proximal region of the sheath outside the patient. The lumen of the sheath 212 is sized and shaped to receive the shunt 10 in its collapsed delivery state. In addition, the outer tube 210 may be movably disposed within the lumen of the sheath 212 such that the dilator 203 may be moved relative to the sheath 212, for example, via actuation of handles independently coupled to the outer tube 210, the inner tube 202, and the sheath 212.

[0062] The distal region 214 of the sheath 212 may be formed from an elastic material, such as superelastic Nitinol, and may be transitionable between a contracted state and an expanded state in which the sheath 212 has a substantially tubular shape. For example, the distal region 214 may be heat set during manufacture in the expanded state, thereby biasing the distal region 214 toward the expanded state, as shown in FIG. 2E. Thus, prior to insertion into a patient, the distal region 214 may be contracted and positioned between the distal portion 204 and the proximal portion 208 of the dilator 203, as shown in FIG. 2A. For example, the distal portion 204 and the proximal portion 208 may initially be decoupled, e.g., spaced apart from one another, thereby providing a gap therebetween, and upon contraction of the distal region 214 of the sheath 212, as the distal end of the distal region 214 is forced to contract radially inward toward the inner tube 202, the distal portion 204 and the proximal portion 208 are caused to move toward one another, sandwiching the distal region 214 therebetween and maintaining the distal region 214 in its contracted state. Further, as shown in FIG. 2B, at least the distal region 214 of the sheath 212 may be encapsulated with a biocompatible material 215, e.g., a polyether block amide (PEBA), such as PEBAX® (available by Arkema, Colombes, France). As shown in FIG. 2B, for example, a proximal portion of the distal region 214 within the distal portion of the sheath 212 may remain unencapsulated. 2B, the inner surface of the sheath 212 may be lined with a layer 217, such as polytetrafluoroethylene (PTFE). Thus, the sheath 212 and at least a portion of the layer 217 may sandwich a proximal portion of the distal region 214. Alternatively, in some embodiments, the sheath 212 and the distal region 214 may be formed from a unitary structure.

[0063] 2A, in its contracted state, the distal region 214 can have a dome shape such that a distal end of the distal region 214 has an inner diameter that is smaller than the inner diameter of the portion of the sheath 212 proximal to the distal region 214. The curvature of the distal region 214 can be selected such that when the distal region 214 is sandwiched between the distal portion 204 and the proximal portion 208 of the dilator 203, there is a step-free transition between the distal region 214 and the distal portion 204, thereby forming a continuous dilator.

[0064] FIG. 2C illustrates an exemplary distal region of the sheath. As would be understood by one of ordinary skill in the art, the axial length of the distal region 214 can be longer than that shown in FIG. 2A. As shown in FIG. 2C, in its contracted state, the distal region 214 can have a plurality of tapered slots, e.g., longitudinal slits 216, arranged circumferentially along the distal region 214. Each of the plurality of longitudinal slits 216 extends from a distal end of the distal region 214 toward a proximal region of the sheath 212 and has a length selected such that fingers formed therebetween can be crimped to fit closely around the dilator 203 between the distal portion 204 and the proximal portion 208 in the contracted state.

[0065] As shown in FIG. 2D, the distal portion 204 and the proximal portion 208 may be decoupled by moving the distal portion 204 distally relative to the proximal portion 208, or by moving the proximal portion 208 proximally relative to the distal portion 204, or both, thereby releasing / disengaging the distal region 214 of the sheath 212. Thus, the distal region 214 will return to its natural expanded tubular configuration, as shown in FIG. 2E. As shown in FIG. 2E, the distal region 214 of the sheath 212 is expanded along the multiple longitudinal slits 216 such that each of the longitudinal slits forms a V-shape. The width of the distal end of each finger between adjacent longitudinal slits may depend on the number of slits in the distal region 214. For example, the distal region 214 may have two, four, eight, or more longitudinal slits 216 forming an equal number of fingers such that each finger has a trapezoidal shape. In one embodiment, the distal ends of the fingers may be rounded or smoothed to prevent them from damaging the shunt 10 during its delivery or from traumatizing tissue during withdrawal of the sheath from the patient. The shunt 10 may be deployed by retracting the sheath 212 proximally relative to the dilator 203, thereby implanting the shunt 10 in the atrial septum AS, as shown in FIG.

[0066] Delivery of the shunt 10 using the delivery device 200 described above may proceed as follows. First, the shunt 10 may be folded into its folded delivery state within the sheath 212 in a manner similar to that described above with respect to the sheath 110. Next, the inner tube 202 may be received through the distal end of the outer tube 210, which may be advanced over the inner tube 202 until the proximal portion 208 is adjacent the distal portion 204. The dilator 203 may then be advanced through the lumen of the sheath 212 until the distal portion 204 and the proximal portion 208 are adjacent the distal region 214 of the sheath 212. The distal portion 204 and the proximal portion 208 may be sufficiently spaced such that the distal region 214 may be retracted to its retracted state such that the distal end of the distal region 214 is positioned between the distal portion 204 and the proximal portion 208. Distal portion 204 and proximal portion 208 can be moved toward one another to sandwich the distal end of distal region 214 between them and locked into place. Each of inner tube 202, outer tube 210, and sheath 212 can be coupled at their proximal regions to a handle for use by a clinician such that each component can be independently actuated via the handle.

[0067] Guidewire 101 may be advanced to a target location, for example, through an atrial septal puncture in the patient's left atrium. Device 200 may be advanced over guidewire 101 via guidewire lumen 206 until distal portion 204 contacts the atrial septal puncture. Device 200 may be further advanced such that dilator 203 enlarges the atrial septal puncture as tissue surrounding the puncture is smoothly guided over distal portion 204, followed by distal region 214 and sheath 212. Unlike other known delivery systems, a separate dilator, which is subsequently removed, is not required to enlarge the atrial septal puncture.

[0068] Under visualization methods such as fluoroscopy and / or ultrasound imaging, the target position of the device 200 relative to the atrial septum may be verified, for example, via radiopaque markers on the sheath 212. The distal and proximal portions 204 and 208 may then be moved away from one another, thereby releasing / disengaging the distal region 214 such that it expands to its expanded tubular shape. While the expander 203 and shunt 10 remain stationary relative to the atrial septum, the sheath 212 may be retracted proximally to expose the distal portion of the shunt 10 such that it deploys within the left atrium. The shunt 10 may be maintained stationary relative to the atrial septum using a device within the sheath 212 such as those described in WO2020202046, the entire contents of which are incorporated herein by reference. For example, a device having multiple hooks may be used to engage the proximal portion of the shunt 10 within the sheath 212.

[0069] After the distal portion of the shunt 10 has been deployed within the left atrium, the delivery device 200 may be retracted proximally until the distal portion of the shunt 10 contacts the atrial septal wall. The sheath 212 may then be further retracted proximally while the shunt 10 is held stationary against the atrial septum until the proximal portion of the shunt 10 is exposed from the distal region 214 of the sheath 212 and deployed within the patient's right atrium, as shown in FIG. 2F. The delivery device 200 may then be removed from the patient, leaving the shunt 10 implanted in the atrial septum.

[0070] 3A-3G, an exemplary delivery device 300 for delivering an inter-atrial shunt device 10 to the atrial septum is provided. The delivery device 300 includes a sheath 302 and a balloon catheter 310. The sheath 302 may have a lumen sized and shaped to receive the balloon catheter 310 therein. As described in further detail below, the balloon catheter 310 has an inflatable balloon 312 disposed at a distal region thereof. The lumen of the sheath 302 is further sized and shaped to receive the shunt 10 in its collapsed delivery state and includes a distal portion 304 having a plurality of longitudinal slits 306. The distal portion 304 may be formed from a malleable material, such as martensitic nitinol or stainless steel, such that the distal portion 304 is in its contracted state prior to delivery / deployment of the shunt 10 in the atrial septum.

[0071] As shown in FIG. 3A, the distal ends of the fingers 307 formed by the longitudinal slits 306 of the sheath 302 have a rounded shape and may contact one another in a contracted state. The rounded shape of the distal ends of the fingers 307 defines an opening when the distal portion 304 is in its contracted state. Thus, as further shown in FIG. 3A, the distal tip 313 of the balloon 312 may be pointed such that the distal tip 313 protrudes through the opening formed by the fingers 307, thereby forming a continuous dilator with the distal portion 304. The rounded shape of the distal ends of the fingers 307 of the distal portion 304 helps protect the balloon 312 and the shunt 10 from damage during balloon expansion of the fingers 307 as well as during deployment of the shunt 10, as described in more detail below. Additionally, as shown in FIG. 3A, the sheath 302 may further include a radiopaque marker 308 to aid in verification of the delivery device 300 against the atrial septum during delivery / deployment of the shunt 10.

[0072] As shown in Fig. 3B, the balloon catheter 310 has an inflatable balloon 312 disposed at its distal region and includes a fluid lumen 311 for introducing fluid into the balloon 312 to inflate / deflate the balloon 312. Thus, as shown in Fig. 3B, the balloon 312 may be positioned within the lumen of the sheath 302 adjacent the longitudinal slit 306 in an inflated state such that the distal tip 313 of the balloon 312 extends beyond the distal end of the distal portion 304 when the distal portion 304 is in its deflated state, thereby forming a continuous dilator. The balloon 312 may be inflated prior to delivery of the delivery device 300 to the atrial septum, or alternatively, the balloon 312 may be in a deflated state until the delivery device 300 is delivered to the atrial septum and then inflated. In an inflated state, the balloon 312 can provide additional support to the distal portion 304 during delivery of the delivery device 300, as shown in FIG. 3B.

[0073] Additionally, delivery device 300 may include a guidewire lumen 314 extending through balloon catheter 310, the guidewire lumen 314 being sized and shaped to receive a guidewire therethrough. Thus, device 300 may be advanced over guidewire 101 via guidewire lumen 314 until distal tip 313 of balloon 312 contacts the atrial septal puncture. Device 300 may be advanced further, causing distal tip 313 and distal portion 304 to enlarge the atrial septal puncture as tissue surrounding the puncture is smoothly guided over distal tip 313, and subsequently distal portion 304 and sheath 302.

[0074] Under visualization methods, such as fluoroscopy and / or ultrasound imaging, the target location of the device 300 relative to the atrial septum can be verified, for example, via a radiopaque marker 308 on the sheath 302. The balloon catheter 310 can then be advanced distally, thereby As shown in Figure 3C, the balloon 312, in its inflated state, pushes against the distal portion 304, causing it to expand radially outward and transition to an expanded state. Radiopaque markers 316 on the outer surface of the balloon 312 can be used to visualize the balloon 312 under fluoroscopy relative to the sheath 302 and ensure that the distal portion 304 has been sufficiently expanded. The balloon 312 can then be deflated, while the distal portion 304 remains in its expanded state, as shown in Figure 3D.

[0075] The shunt 10 may be maintained stationary against the atrial septum using a device within the sheath 302, such as that described in WO2020202046, the entire contents of which are incorporated herein by reference. For example, the pusher 318 may have a number of hooks that may be used to engage a proximal portion of the shunt 10 within the sheath 302. The pusher 318, slidably disposed within the lumen of the sheath 302, may then be advanced distally relative to the sheath 302 to push the shunt 10 distally through the lumen of the sheath 302 until the distal portion of the shunt 10 is exposed beyond the distal portion 304 such that the distal portion of the shunt 10 is deployed into the left atrium, as shown in FIG.

[0076] After the distal portion of the shunt 10 has been deployed within the left atrium, the delivery device 300 may be retracted proximally until the distal portion of the shunt 10 contacts the atrial septal wall. The sheath 302 may then be further retracted proximally while the shunt 10 is held stationary against the atrial septum until the proximal portion of the shunt 10 is exposed from the distal portion 304 of the sheath 302 and deployed within the patient's right atrium, as shown in FIG. 3F. The balloon 312 may then be again advanced through the sheath 302 and again inflated so that the balloon 312 is adjacent the distal portion 304, thereby reforming a continuous device, as shown in FIG. 3G. The delivery device 300 may then be removed from the patient, leaving the shunt 10 implanted in the atrial septum.

[0077] Alternatively, in some embodiments, the distal portion 304 may be formed from a shape memory material with an austenitic finish (AF) temperature higher than body temperature, such as martensitic nitinol. Thus, the distal portion 304 may be heat set to its contracted state for delivery of the delivery device 300. The balloon 312 may then be advanced distally relative to the sheath 302 while the distal portion 304 is in its martensite phase to expand the distal portion 304 to its expanded state as described above. After the shunt 10 is deployed in the atrial septum as described above, the distal portion 304 may be transitioned back to its contracted state by exposing the distal portion 304 to heat. For example, heated saline having a temperature higher than the AF temperature of the distal portion 304 may be injected through the sheath 302 to transfer heat to the distal portion 304, thereby transitioning the distal portion 304 from its expanded state to its contracted state. The delivery device 300 may then be removed from the patient, leaving the shunt 10 implanted in the atrial septum.

[0078] 4A and 4B, an exemplary delivery device 400 for delivering an interatrial shunt device 10 to the atrial septum is provided. As shown in FIG. 4A, the delivery device 400 includes a sheath 402 and a dilator 403. The distal portion 12 of the shunt device 10 may be used as part of the delivery device 400 to facilitate dilation of the atrial septal puncture as described in further detail below. The sheath 402 has a lumen extending from a distal region of the sheath 402 to a proximal region of the sheath outside the patient. The lumen of the sheath 402 is sized and shaped to receive at least a portion of the shunt 10 in its collapsed delivery state.

[0079] The dilator 403 may be formed from a wire mesh and includes an expandable braided tip 408 that may transition between an expanded and contracted state. For example, the proximal portion 407 may be coupled to a distal end of the outer tube 412 such that the proximal portion 407 may be actuated via the outer tube 412 and the piston 416. As shown in FIG. 4A, the piston 416 may include a cavity 418 sized and shaped to engage a pin 414 at the proximal end of the outer tube 412. Thus, actuation of the piston 416, for example, via actuation of a patient's external handle independently coupled to the piston 416, will push and pull the outer tube 412 via the pin 414. Additionally, the distal portion 409 may be coupled to the outer tube 412 and the inner tube 410 movably disposed within the pin 414 such that the proximal portion 407 may be moved relative to the distal portion 409, e.g., via actuation of a patient-external handle independently coupled to the piston 416 and the inner tube 410, thereby transitioning the braided tip 408 between its expanded and contracted states. For example, the braided tip 408 will expand as the distal portion 409 and the proximal portion 407 are moved closer together and contract as the distal portion 409 and the proximal portion 407 are moved farther apart. The outer tube 412 and the inner tube 410 may be concentric tubes, e.g., PEEK tubes.

[0080] In addition, the piston 416 can engage and maintain the shunt 10 in its collapsed delivery state and can maintain the shunt 10 stationary against the atrial septum. For example, the piston 416 can include a number of hooks that can be used to engage a proximal portion of the shunt 10 within the sheath 402.

[0081] As shown in FIG. 4A, in the expanded state, the distal portion of the braided tip 408 may form an atraumatic cone shape that may be inserted through the atrial septal puncture to enlarge the puncture without damaging the surrounding tissue. Thus, the wire mesh of the braided tip 408 may be encapsulated with a biocompatible material to facilitate the enlargement of the atrial septal puncture. Alternatively, the distal portion of the braided tip 408 may have a sharp needle tip that may be used to create a puncture in the atrial septum such that further advancement of the braided tip 408 across the atrial septum will enlarge the puncture. The dilator 403 may have a guidewire lumen 406 extending through the inner tube 410, the guidewire lumen 406 being sized and shaped to receive a guidewire therethrough, such that the device 400 may be advanced across the atrial septum over a conventional guidewire. Thus, the guidewire lumen 406 may extend through the braided tip 408 and the inner tube 410 .

[0082] As shown in FIG. 4A, the distal portion 12 of the shunt device 10 may be used as part of a delivery device 400 to facilitate dilation of the atrial septal puncture. For example, the distal portion 12 of the shunt device 10 may be formed from a shape memory material, such as martensitic nitinol, with an austenite finish temperature Af above body temperature, e.g., above 45 degrees Celsius, and may be heat set in an expanded configuration. Additionally, the distal portion 12 may be crimped into a folded dilator state, as shown in FIG. 4A. In its folded dilator state, the distal portion 12 of the shunt device 10 may contact the outer surface of the braided tip 408, preferably at a point along the outer surface of the braided tip 408 where the cross-sectional area of ​​the braided tip increases from the distal portion 409 toward the proximal portion 407. Thus, the braided tip 408 can be expanded such that there is a step-free transition between the braided tip 408 and the distal portion 12 of the shunt device 10, thereby forming a continuous dilator. Further, as shown in FIG. 4A, the distal region 404 of the sheath 402 can have a geometry that promotes a step-free transition between the sheath 402 and the distal portion 12 of the shunt device 10. For example, the distal region 404 of the sheath 402 can curve radially inward to engage the distal portion 12 of the shunt device 10.

[0083] The distal portion 12 of the shunt device 10 may be transitioned from its collapsed expander state to an expanded deployed state, for example, via the application of heat. For example, a warm fluid, such as saline, may be introduced across the distal portion 12 of the shunt device 10, thereby heating the distal portion 12 above a predetermined Af transition temperature and expanding the distal portion 12 to its heat-set, expanded, deployed state. The warm fluid may be introduced within the sheath 402 outside the outer tube 412. Alternatively, or in addition, the sheath 402 may further include one or more fluid channels 419 extending through the piston 416 and coupled to a source of fluid external to the patient for introducing the warm fluid across the distal portion 12.

[0084] Delivery of the shunt 10 using the delivery device 400 described above may proceed as follows. First, in a manner similar to that described above with respect to the sheaths 110, 212, the distal portion 12 of the shunt device 10 may be crimped to a collapsed dilator state, as shown in FIG. 4A, and the remainder of the shunt 10 may be crimped to its collapsed delivery state within the sheath 402. The axial position of the shunt 10 within the sheath 402 may be adjusted such that the distal portion 12 of the shunt 10 is exposed from the distal end of the distal region 404 of the sheath 402.

[0085] Next, the dilator 403 may then be advanced through the lumen of the sheath 402 until the braided tip 408 is adjacent the distal portion 12 of the shunt device 10. The braided tip 408 may be expanded to its expanded state via actuation of the inner tube 410 and piston 416, and thus the outer tube 412, as described above to form a step-free transition between the distal portion 12 of the shunt device 10 and the braided tip 408. For example, the inner tube 410, piston 416, and sheath 402 may each be coupled at their proximal regions to a handle for use by a clinician such that each component may be independently actuated via the handle.

[0086] A guidewire 101 may be advanced to a target location, for example, through an atrial septal puncture in the patient's left atrium. The device 400 may be advanced over the guidewire 101 via the guidewire lumen 406 until a distal portion 409 of the braided tip 408 contacts the atrial septal puncture. The device 400 may be advanced further, whereby the dilator 403 enlarges the atrial septal puncture as tissue surrounding the puncture is smoothly guided over the braided tip 408, and subsequently the distal portion 12 of the shunt device 10 and the sheath 402. Unlike other known delivery systems, a separate dilator, which is subsequently removed, is not required to enlarge the atrial septal puncture.

[0087] Under visualization methods such as fluoroscopy and / or ultrasound imaging, the target position of the device 400 relative to the atrial septum may be verified, for example, via radiopaque markers on the sheath 402. The braided tip 408 may be retracted via movement of the inner tube 410 relative to the outer tube 412, as described above. Warm fluid may then be introduced over the distal portion 12 of the shunt device 10 to transition the distal portion 12 from its collapsed expander state to its expanded deployed state within the left atrium. The shunt 10 may be maintained stationary relative to the atrial septum via the piston 416.

[0088] After the distal portion of the shunt 10 has been deployed within the left atrium, the delivery device 400 may be retracted proximally until the distal portion of the shunt 10 contacts the atrial septal wall. The sheath 402 may then be further retracted proximally, while the shunt 10 is held stationary against the atrial septum, until the proximal portion of the shunt 10 is exposed from the distal region 404 of the sheath 402 and deployed within the patient's right atrium. The delivery device 400 may then be removed from the patient, leaving the shunt 10 implanted in the atrial septum.

[0089] 5A and 5B, an exemplary delivery device 500 is provided operatively coupled to a handle 530 for delivering an interatrial shunt device 10 to the atrial septum. As shown in FIG. 5A, the delivery device 500 includes a sheath 502, a dilator, e.g., a balloon catheter 510, slidably disposed within the lumen of the sheath 502, a release knot 516 for releasably coupling to the shunt 10 at a knot connection 518 within the lumen of the sheath 502, and a pusher 520 slidably disposed within the lumen of the sheath 502. For example, the release knot 516 can be a Dyneema wire / cord. The lumen of the sheath 502 can be sized and shaped to receive the shunt 10 in its collapsed delivery state. The distal region 504 of the sheath 502 may be linear or may have a geometry that promotes a step-free transition between the distal region 504 and the balloon 512 to form a smooth, continuous dilator when the balloon 512 is in its expanded state, as described in more detail below. For example, the distal region 504 of the sheath 502 may curve radially inward to engage the outer surface of the balloon 512. Additionally, the delivery device 500 may include a guidewire lumen 514 extending through the balloon catheter 510, the guidewire lumen 514 being sized and shaped to receive a guidewire therethrough.

[0090] Each of the sheath 502, balloon catheter 510, release knot 516, and pusher 520 may be operatively coupled to a handle 530 such that they are all independently actuable relative to one another. For example, as shown in FIG. 5B, a proximal region 506 of the sheath 502 may be coupled to the handle 530, the balloon catheter 510 may be operatively coupled to an actuator 532 of the handle 530 that may be actuated to move the balloon catheter 510 axially relative to the sheath 502, the pusher 520 may be operatively coupled to an actuator 534 of the handle 530 that may be actuated to move the pusher 520 axially relative to the sheath 502, and a first end of the release knot 516 may be operatively coupled to an actuator 534 of the handle 530 that may be actuated to move the pusher 520 axially relative to the sheath 502. , a second end of the release knot 516 may be operatively coupled to a release actuator 536 of the handle 530, which may be actuated to break down the knot connection 518 and disengage the release knot 516 from the shunt 10, and a second end of the release knot 516 may be operatively coupled to a retrieval actuator 538 of the handle 530, which may be actuated to retract the release knot 516, and thus the shunt 10, through the knot connection 518, within the lumen of the sheath 502. In some embodiments, to prevent accidental disengagement between the release knot 516 and the shunt 10, a lock 537 may be included, which may be actuated to transition between a locked configuration, in which the release actuator 536 may not be actuated relative to the handle 530, and an unlocked configuration, in which the release actuator 536 may be actuated and moved along the handle 530. Further, to prevent accidental partial retrieval of the shunt 10, a lock 539 may be included which may be actuated to transition between a locked configuration in which the retrieval actuator 538 may not be actuated relative to the handle 530, and an unlocked configuration in which the retrieval actuator 538 may be actuated and moved along the handle 530.

[0091] Referring again to 5A, the balloon catheter 510 may include an inflatable balloon 512 disposed at its distal region. The balloon 512 is configured to transition between a deflated compressed state and an inflated expanded state. Thus, the balloon catheter 510 may include a fluid lumen fluidly coupled to a fluid source for introducing fluid into the balloon 512 to inflate / deflate the balloon 512. In addition, the balloon 512 may be formed with a tapered conical shape at its distal end. The balloon 512 may have a symmetrical profile such that when the balloon 512 is in its expanded state, both its proximal and distal ends have a tapered conical shape. When the balloon 512 is positioned adjacent to the distal region 504 of the sheath 502, in its expanded state, the outer surface of the balloon 512 may form a stepless transition between the distal region 504 and the balloon 512 to form a smooth, continuous dilator.

[0092] Further, the pusher 520 may be a multi-lumen catheter slidably disposed within a lumen of the sheath 502, the multi-lumen catheter having a distal end configured to engage the shunt 10 in its collapsed delivery state within the lumen of the sheath 502, e.g., via actuation of the actuator 534. For example, the pusher 520 may have a first lumen sized and shaped to slidably receive the balloon catheter 510 (including the balloon 512 in its collapsed state) therethrough, and one or more lumens sized and shaped to slidably receive one or both ends of the release knot 516 therethrough. For example, the pusher 520 may have a single lumen sized and shaped to slidably receive both ends of the release knot 516 therethrough, or, alternatively, the pusher 520 may have one lumen sized and shaped to slidably receive a first end of the release knot 516 therethrough that is operatively coupled to the release actuator 536, and another lumen sized and shaped to slidably receive a second end of the release knot 516 therethrough that is operatively coupled to the retrieval actuator 538. The lumen of the pusher 520 that slidably receives the balloon catheter 510 may be coaxial with the longitudinal axis of the sheath 502, and the one or more lumens that slidably receive the ends of the release knot 516 may not be coaxial with the longitudinal axis of the sheath 502. Thus, the pusher 520 can be advanced distally relative to the sheath 502 and balloon catheter 510 via actuation of the actuator 534, pushing the shunt 10 distally through the lumen of the sheath 502 until at least a distal portion of the shunt 10 is exposed beyond the distal region 504 and transitions to its expanded, deployed state, e.g., within the left atrium.

[0093] As described above, the release knot 516 may be releasably coupled to the shunt 10 in its collapsed delivery state within the lumen of the sheath 502 via a knot connection 518. FIG. 6A illustrates an exemplary knot mechanism for releasably coupling the release knot 516 to the shunt 10. As shown in FIG. 6A, the release knot 516 may be formed from a single force transmission element, e.g., a Dyneema wire / cord, having a release wire portion, e.g., a release end 517, a knot connection 518, and a standing portion, e.g., a retrieval end 519. For example, the release knot 516 may be tied to the shunt 10, e.g., at a proximal portion of the shunt 10, to form the knot connection 518, whereby the release end 517 and the retrieval end 519 extend from the knot connection 518. The knot connection 518 may be a knot such as a Painta hitch or a quick tie and release (QTaR) hitch, whereby applying a retraction force to the release end 517, e.g., via the release actuator 536, causes the release end 517 to pull on the knot connection 518 in a manner that causes the knot connection 518 to break apart and disengage the release knot 516 from the shunt 10, while applying a retraction force to the retrieval end 519, e.g., via the retrieval actuator 538, causes the retrieval end 519 to pull on the knot connection 518, thereby pulling the shunt 10 within the lumen of the sheath 502. Thus, the release knot 516 may have a predetermined amount of extra length, e.g., slack, disposed within the device 800, e.g., within the sheath 502 / pusher 520 distal to the handle 520, such that when the shunt 10 is moved distally within the sheath 502 via the pusher 520, the release knot 516, which is coupled to the shunt 10 via the knot connection 518, may also move distally within the sheath 502 without applying force to the release actuator 536 or the retrieval actuator 538. Thus, actuation of the release actuator 536 and / or retrieval actuator 538 may not disengage the shunt 10 or partially retrieve the shunt 10 until the shunt 10 is partially deployed from the sheath 502 (e.g., when the slack in the release knot 516 is removed).

[0094] As will be understood by one of ordinary skill in the art, the knot configuration illustrated in Figure 6A is one example of numerous knot configurations suitable for use with the delivery devices described herein in accordance with the principles of the present disclosure. For example, Figure 6B illustrates another exemplary release knot 516' having a release wire portion, e.g., a release end 517', a knot connection 518', and a standing portion, e.g., a retrieval end 519'. The knot connection 518' may have a configuration similar to that of the knot connection 518, except that the knot connection 518' includes an additional loop to provide additional fixation between the release knot 516' and the shunt.

[0095] Additionally, the release knots described herein may be used to facilitate the transition of the shunt 10 from its expanded, deployed state toward its folded, delivery state, as described, for example, in commonly assigned U.S. Patent No. 10,940,296 to Keren, the entire contents of which are incorporated herein by reference. For example, in some embodiments, a release knot may be coupled to a proximal portion of the shunt 10 and both the retrieval and release ends may be threaded through two or more loops of the proximal end of the shunt 10, for example, at evenly spaced points around the circumference of the proximal end of the shunt 10, such that retraction of the retrieval end of the release knot, for example, through the lumen of the pusher 520, applies an inward force to the proximal portion of the shunt 10, thereby causing the proximal portion of the shunt 10 to fold radially inwardly into its folded, delivery state; whereas retraction of the release end of the release knot causes the knot connection to degrade, disengaging the release knot from the shunt 10. Thus, the release knot may remain coupled to the shunt 10 when the shunt 10 is fully deployed in the atrial septum, for example, by having sufficient slack in the delivery device 500 distal to the handle 530. Once the shunt 10 is satisfactorily deployed, the release knot may be disengaged from the shunt 10 by retraction of the release end of the release knot, and the entire release knot, including both the release and retrieval ends, may be retracted back into the delivery sheath 502. If deployment of the shunt 10 is not satisfactory, the retrieval end of the release knot may be retracted proximally to transition a proximal portion of the shunt 10 toward its collapsed delivery state, and the shunt 10 may be further retracted back into the lumen of the sheath 502 via retraction of the retrieval end of the release knot for redeployment or removal.

[0096] Additionally or alternatively, a release knot may be coupled to an intermediate portion of the shunt 10, for example, at a neck region between the proximal and distal flared end regions of the shunt 10, and both the retrieval and release ends may be looped around an outer surface of the intermediate portion of the shunt 10 toward the knot connection. Once the shunt 10 has been satisfactorily deployed, the release knot may be disengaged from the shunt 10 by retraction of the release end of the release knot, and the entire release knot, including both the release and retrieval ends, may be pulled back into the delivery sheath 502. If the shunt 10 is not satisfactorily deployed, the shunt 10 may be retrieved back into the delivery sheath 502, for example, by proximal retraction of the retrieval end of the release knot through the lumen of the pusher 520, which applies an inward force to the intermediate portion of the shunt 10, thereby causing the intermediate portion of the shunt 10 to fold radially inward toward its folded delivery state. Collapsing the intermediate portion of the shunt 10 can cause the proximal portion of the shunt 10 to further collapse at least partially, such that the shunt 10 can then be further retracted back into the lumen of the sheath 502 via retraction of the retrieval end of the release knot for redeployment or removal.

[0097] Alternatively, a release knot may be tied to the proximal portion of the shunt 10, with both the retrieval and release ends threaded through an initial loop at the proximal end of the shunt 10 and then threaded through a central passageway of the shunt 10, out of the central passageway, looped around the outer surface of the mid-portion of the shunt 10, and back toward the knot connection, such that, for example, retraction of the retrieval end of the release knot through the lumen of the pusher 520 applies an inward force to the mid-portion of the shunt 10, thereby causing the mid-portion of the shunt 10 to fold radially inward toward its folded delivery state; while retraction of the release end of the release knot causes the knot connection to degrade, disengaging the release knot from the shunt 10. As will be understood by one of ordinary skill in the art, two or more release knots may be tied to the shunt, for example, at evenly spaced locations around the circumference of the shunt, to facilitate transition of the shunt 10 toward its folded delivery state for full and / or partial retrieval.

[0098] 7A-7H, exemplary method steps are provided for delivering the shunt 10 to an implantation site in the atrial septum via a delivery device 500. As shown in FIG. 7A, a fluid source 540 (e.g., a syringe pump) fluidly coupled to the balloon 512 via a fluid lumen 511 of the balloon catheter 510 may be actuated to move fluid into the balloon 512, thereby expanding the balloon 512 from its pursed, folded state to its inflated, expanded state whereby an outer surface of the balloon 512 engages an inner surface of the lumen of the sheath 502 at a distal region 504 of the sheath 502, thereby forming a smooth, continuous expander for delivering the delivery device 500 to the atrial septum.

[0099] The device 500 with the balloon 512 in its expanded state at the distal region 504 of the sheath 502 can be advanced over the guidewire 101 through the guidewire lumen 514 until the distal portion of the balloon 512 contacts the puncture opening in the atrial septum AS. The device 500 can be advanced further such that the balloon 512 enlarges / dilates the puncture opening in the atrial septum AS while the tissue surrounding the puncture opening is smoothly guided over the distal portion of the balloon 512 and subsequently the distal region 504 of the sheath 502, as shown in FIG. 7B. Under visualization methods such as fluoroscopy and / or ultrasound imaging such as transesophageal echo (TEE) or intracardiac echo (ICE), the target position of the device 500 relative to the atrial septum AS can be verified, for example, via radiopaque markers on the sheath 502. Preferably, the device 500 is positioned relative to the atrial septum AS such that the distal region 504 is spaced from the atrial septum AS in the left atrium by at least a predetermined distance to ensure full deployment of the distal portion of the shunt 10 within the left atrium, as described in further detail below.

[0100] Next, as shown in FIG. 7C, the balloon 512 may be pursed via the fluid source 540, for example, by actuating a syringe pump to draw fluid from the balloon 512, such that the balloon 512 transitions to its pursed, folded state. In some embodiments, the shunt 10 may be maintained stationary relative to the atrial septum using a device within the sheath 502, such as that described in WO2020202046. As shown in FIG. 7D, the actuator 532 may then be actuated, for example, moved proximally along the handle 530 from a first position on the handle 530 to a second position on the handle 530, thereby retracting the balloon catheter 510 and the balloon 512 in its pursed state proximally relative to the sheath 502. For example, the balloon catheter 510 may be retracted proximally through the shunt 10 in its collapsed delivery state within the sheath 502 until the balloon 512 is disposed within the lumen of the pusher 520, as shown in FIG. 7D. Thus, the lumen of the sheath 502 may be clear between the shunt 10 and the distal region 504.

[0101] The actuator 534 may then be actuated, as shown in FIG. 7E , for example, moved distally along the handle 530 from a first position on the handle 530 to a second position on the handle 530, thereby moving the pusher 520, and thus the shunt 10, distally relative to the sheath 502 until a distal portion of the shunt 10 is exposed beyond the distal region 504 of the sheath 502 and deployed within the left atrium. For example, as the pusher 520 is advanced distally within the lumen of the sheath 502, the distal end of the pusher 520 engages the proximal end of the shunt 10 in its collapsed delivery state and pushes the shunt 10 distally through the lumen of the sheath 502. As explained above, the distal region 504 may be spaced from the atrial septum AS by at least a predetermined distance such that the distal portion of the shunt 10 may be fully deployed within the left atrium. Thus, the device 500 may then be retracted relative to the atrial septum AS, e.g., by moving the handle 530 proximally, until the deployed distal portion of the shunt 10 contacts the atrial septum AS, as shown in Figure 7F. The desired position of the shunt 10 relative to the atrial septum AS may be observed by the physician, e.g., via feedback of the force applied to the device 500 via the atrial septum AS, and / or may be visually verified, e.g., via fluoroscopy and / or ultrasound imaging such as transesophageal echo (TEE) or intracardiac echo (ICE).

[0102] 7G, the release actuator 536 may be actuated, e.g., moved proximally along the handle 530 from a first position on the handle 530 to a second position on the handle 530, thereby retracting the release end 517 of the release knot 516, which causes the knot connection 518 to degrade and disengage the release knot 516 from the shunt 10 within the sheath 502. As explained above, in some embodiments, the lock 537 of the release actuator 536 may be required to transition from its locked configuration to its unlocked configuration prior to moving the release actuator 536 from the first position to the second position. Next, as shown in FIG. 7H, once the shunt 10 is disengaged from the release knot 516, the device 500 can be further retracted proximally against the atrial septum AS, for example, by moving the handle 530 proximally, such that the atrial septum AS applies a force to the deployed distal portion of the shunt 10 to maintain the shunt 10 in a fixed position against the atrial septum AS as the device 500 is retracted proximally until the proximal portion of the shunt 10 is exposed beyond the distal region 504 of the sheath 502 and deployed into the right atrium, thus completing full deployment of the shunt.

[0103] After the shunt 10 is fully deployed in the atrial septum AS, the device 500 may be removed from the patient, leaving the shunt 10 implanted in the atrial septum. In some embodiments, prior to removal, the actuator 532 may be actuated to move the balloon catheter 510 distally within the sheath 502 such that the balloon 512 is positioned within the sheath 502 adjacent the distal region 504, and the balloon 512 may be inflated to its expanded state, for example, via a fluid source 540, as described above, to form a continuous expander with the distal region 504.

[0104] 7I-7K, exemplary method steps are provided for partial retrieval of the shunt 10 during delivery of the shunt 10 at the atrial septum AS. For example, after a distal portion of the shunt 10 has been deployed, e.g., in the left atrium as shown in FIG. 7E or another inappropriate location, it may be desirable to transition the shunt 10 back to its collapsed delivery state within the sheath 502 and retrieve the shunt 10. Thus, as shown in FIG. 7I, the actuator 534 may be actuated, e.g., moved proximally along the handle 530 from a second position on the handle 530 to a first position on the handle 530, thereby moving the pusher 520 proximally relative to the sheath 502 to provide an unobstructed path within the lumen of the sheath 502 for the shunt 10 to be disposed therein in its collapsed delivery state. Next, as shown in FIG. 7J , the retrieval actuator 538 may be actuated, e.g., moved proximally along the handle 530 from a first position on the handle 530 to a second position on the handle 530, thereby retracting the retrieval end 519 of the release knot 516, which pulls the shunt 10 proximally through the knot connection 518 within the lumen of the sheath 502. As the shunt 10 is pulled proximally within the sheath 502, the distal region 504 of the sheath 502 exerts a force against the deployed distal portion of the shunt 10, which causes the distal portion to transition to its collapsed delivery state within the lumen of the sheath 502. As described above, in some embodiments, the lock 539 of the retrieval actuator 538 may be required to transition from its locked configuration to its unlocked configuration prior to moving the retrieval actuator 538 from the first position to the second position.

[0105] When the shunt 10 is in its collapsed delivery state fully within the sheath 502, the device 500 may be removed from the patient, for example, by moving the handle 530 proximally, as shown in Figure 7K. Alternatively, the device 500 may be repositioned relative to the atrial septum AS such that the shunt 10 may be implanted therein, according to the delivery method described above with respect to Figures 7E-7H.

[0106] Alternatively, as described above, the release knot 516 may remain coupled to the shunt 10 during full deployment of the shunt 10 at the atrial septum AS. Thus, the release actuator 536 may not be actuated prior to retracting the device 500 proximally relative to the atrial septum AS, thereby completing full deployment of the shunt by deploying a proximal portion of the shunt 10 into the right atrium. In this embodiment, responsive to satisfactory full deployment of the shunt 10 at the atrial septum AS, the release actuator 536 may then be actuated to break the knot connection 518 and disengage the release knot 516 from the shunt 10. If deployment is not satisfactory, the retrieval end 519 can be retracted proximally, for example via actuation of the retrieval actuator 538, to facilitate transition of the proximal and / or intermediate portions of the shunt 10 toward the collapsed delivery state, as described above, thereby causing the shunt 10 to be retracted back into the lumen of the sheath 502 for redeployment or removal.

[0107] 8A-8I, exemplary method steps are provided for delivering an inter-atrial shunt device 10 to the atrial septum via an exemplary delivery device 800 operatively coupled to a handle 830. Device 800 may be constructed similarly to delivery device 500. For example, sheath 802 having distal region 804 and proximal region 806 corresponds to sheath 502 having distal region 504 and proximal region 506, balloon catheter 810 having inflatable balloon 812 and fluid lumen 811 corresponds to balloon catheter 510 having inflatable balloon 512 and fluid lumen 511, pusher 820 corresponds to pusher 520, and release knot 816 having release end 817, knot connection 818, and retrieval end 819 corresponds to release knot 516 having release end 517, knot connection 518, and retrieval end 519. The device 800 differs from the delivery device 500 in that the retrieval end 819 may be coupled to a distal portion of the pusher 820, rather than extending through the length of the pusher 820 from the knot connection 818 to a retrieval actuator of the handle 830. Thus, the handle 830 does not require a separate retrieval actuator, as the handle 830 may be constructed similarly to the handle 530, such that the handle 830 is coupled to the proximal region 806 of the sheath 802, the balloon catheter actuator 832 corresponds to the balloon catheter actuator 532, the pusher actuator 834 corresponds to the pusher actuator 534, the release actuator 836 corresponds to the release actuator 536, and the fluid source 840 corresponds to the fluid source 540. For example, actuation of the actuator 832, e.g., moving the actuator 832 proximally along the handle 830, causes the pusher 820, and thus the shunt 10 and the retrieval end 819 coupled thereto, to move into position within the lumen of the sheath 802. Further, the pusher 820 does not have a separate lumen for receiving the retrieval end 819 .

[0108] Similar to the free end 517 as described above, the free end 817 may have slack within the device 800 such that actuation of the release actuator 836 may not cause disassembly of the knot connection 818 until the shunt 10 is partway deployed from the sheath 802. Alternatively, in some embodiments, the release actuator 836 may be releasably coupled to the pusher actuator 834 such that the release actuator 836 moves with the pusher actuator 834 when the pusher actuator 834 is actuated to move the pusher 820, and thus the shunt 10, distally within the sheath 802. Thus, the free end 817 may not have slack within the device 800 as the free end 817 moves distally with the pusher 820 via movement of the release actuator 836. The release actuator 836 can be decoupled from the pusher actuator 834, for example, via a lock 837 or another locking mechanism that couples the release actuator 836 and the pusher actuator 834, as described above, and then independently actuated to pull on the release end 817 to break down the knot connection 818 and disengage the release knot 816 from the shunt 10.

[0109] In some embodiments, the release actuator 836 may include a rope clutch mechanism through which the release end 817 may be threaded. For example, the rope clutch mechanism may be in an open state during actuation of the pusher actuator 834, with the release end 817 moving through the rope clutch mechanism as the pusher 820, and thus the retrieval end 819 coupled thereto, is moved distally through the sheath 802. As explained above, if partial retrieval of the shunt 10 is desired, the pusher actuator 834 may be actuated to retract the shunt 10 through the pusher 820, and thus the knot connection 818, within the sheath 802. To disengage the release knot 816 from the shunt 10, the rope clutch mechanism may be transitioned to a closed state, e.g., via a lock 837 or another closure mechanism operatively coupled to the rope clutch mechanism, to secure the release end 817 to the release actuator 836, whereby actuation of the release actuator 836 pulls on the release end 817 and breaks down the knot connection 818.

[0110] Similar to the method steps for delivery of the shunt 10 via device 500 described above with respect to Figures 7A-7H, as shown in Figure 8A, device 800 with balloon 812 in an inflated expanded state adjacent distal region 804 of sheath 802 may be delivered through a hole in the atrial septum AS such that the balloon 812 enlarges / dilates the puncture opening in the atrial septum AS as tissue surrounding the puncture opening is smoothly guided over the distal portion of balloon 812 and then distal region 804 of sheath 802. Additionally, balloon 812 may be puckered as shown in Figure 8B and retracted proximally within the lumen of pusher 820 via actuator 832 as shown in Figure 8C. As shown in FIG. 8D, the pusher 820 can be advanced distally within the sheath 802 via the actuator 834 to move the shunt 10 distally within the sheath 802 until the distal end of the pusher 820 engages the proximal end of the shunt 10 and a distal portion of the shunt 10 extends beyond the distal region 804 and is deployed within the left atrium.

[0111] As shown in FIG. 8E, the device 800 may then be moved proximally, for example, by moving the handle 830 proximally, until the distal portion of the shunt 10 contacts the atrial septum AS. The release end 817 may then be pulled proximally via the release actuator 836 to break the knot connection 818 and disengage the release knot 818 from the shunt 10 while the retrieval end 819 remains coupled to the distal portion of the pusher 820, as shown in FIG. 8F. In some embodiments, the lock 837 of the release actuator 836 may be required to transition from its locked configuration to its unlocked configuration prior to actuating the release actuator 836. As shown in FIG. 8G, the device 800 may be retracted proximally while the atrial septum AS holds the shunt 10 in place until the proximal portion of the shunt 10 is exposed from the sheath 802 and deployed into the right atrium. The delivery device 800 may then be removed from the patient, leaving behind the implanted shunt 10. As explained above, the balloon 81 may be re-inflated adjacent the distal region 804 prior to removal of the device 800 from the patient.

[0112] As explained above, after a distal portion of the shunt 10 has been deployed, for example, in the left atrium as shown in FIGURE 8D or another inappropriate location, it may be desirable to transition the shunt 10 back to its collapsed delivery state within the sheath 802 and retrieve the shunt 10. Thus, as shown in FIGURE 8H, the actuator 832 may be actuated, for example, moved proximally along the handle 530, thereby moving the pusher 820 proximally within the lumen of the sheath 802, which pulls the retrieval end 819 and the shunt 10 proximally via the knot connection 818 within the lumen of the sheath 802 until the distal portion of the shunt 10 has transitioned to its collapsed delivery state within the sheath 802. The device 800 may then be removed from the patient, as shown in FIG. 8I, or, alternatively, the device 800 may be repositioned relative to the atrial septum AS such that the shunt 10 may be implanted in the atrial septum AS according to the delivery method described above with respect to FIGS. 8D-8G.

[0113] While various illustrative embodiments of the present invention are described above, it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the invention. It is intended that the appended claims cover all such changes and modifications that fall within the true scope of the present invention.

Claims

1. 1. A device for delivering a shunt to the atrial septum of a patient, comprising: a sheath having a proximal region, a distal region, and a sheath lumen extending therethrough, the sheath lumen sized and shaped to receive the shunt in a collapsed delivery state; a balloon catheter configured for movably positioning within the sheath lumen, the balloon catheter including a balloon configured to transition between a deflated, collapsed state and an inflated, expanded state adjacent the distal region to form a continuous, stepless transition between the balloon and the distal region of the sheath; a handle including one or more actuators configured to operate to deploy the shunt in the atrial septum. The device comprising:

2. a pusher slidably disposed within the sheath lumen, the pusher operatively coupled to a pusher actuator of the one or more actuators of the handle; The device of claim 1 , wherein the pusher actuator is configured for actuation to move the pusher within the sheath lumen.

3. 3. The device of claim 2, wherein the pusher actuator is configured to operate to move the pusher distally relative to the sheath such that a distal end of the pusher engages a proximal portion of the shunt in the collapsed delivery state, thereby moving the shunt distally relative to the sheath until a distal portion of the shunt is exposed beyond the distal region of the sheath and transitions from the collapsed delivery state to an expanded, deployed state.

4. The device of claim 2 , further comprising a release knot slidably disposed within the sheath lumen, the release knot configured to be releasably engaged with the shunt via a hitch knot.

5. 5. The device of claim 4, wherein a first end of the release knot is operatively coupled to a release actuator of the one or more actuators on the handle, and a second end of the release knot is operatively coupled to a retrieval actuator of the one or more actuators on the handle, wherein actuation of the release actuator causes the hitch knot to be untied and the release knot to be released from the shunt, and actuation of the retrieval actuator causes the shunt to retract proximally within the sheath lumen through the hitch knot, thereby partially retrieving the shunt.

6. 5. The device of claim 4, wherein a first end of the release knot is operatively coupled to a release actuator of one or more actuators on the handle, a second end of the release knot is operatively coupled to a distal portion of the pusher, actuation of the release actuator unties the hitch knot, causing the release knot to be released and released from the shunt, and actuation of the pusher actuator causes the shunt to retract proximally within the sheath lumen through the hitch knot, thereby partially retrieving the shunt.

7. 5. The device of claim 4, wherein the hitch knot comprises a Painta hitch knot or a Quick Tie and Release (QTaR) hitch knot.

8. The device of claim 1 , wherein the balloon is configured to permit deployment of the shunt through the distal region of the sheath when deflated.

9. The device of claim 1 , wherein the balloon catheter comprises a fluid lumen configured to fluidly couple the balloon to a fluid source.

10. 10. The device of claim 1, wherein the balloon catheter is operatively coupled to a balloon catheter actuator of the one or more actuators of the handle, and actuation of the balloon catheter actuator moves the balloon catheter relative to the sheath.

11. 1. A device for delivering a shunt to an atrial septum of a patient, the device comprising: a sheath configured to be advanced through a hole in the atrial septum, the sheath having a proximal region, a distal region, and a sheath lumen extending therethrough, the sheath lumen sized and shaped to receive the shunt in a collapsed delivery state; and a dilator movably disposed within the sheath lumen, the dilator comprising an expandable portion configured to transition between a first state and a second state, wherein in the second state, the expandable portion engages the distal region of the sheath, wherein: The dilator and sheath are configured such that when the device is advanced through the hole in the atrial septum, the tissue surrounding the hole is smoothly guided over the distal portion of the dilator and the sheath to dilate the hole in the atrial septum.

12. 12. The device of claim 11, wherein the dilator comprises a guidewire lumen sized and shaped to receive a guidewire.

13. The expander comprises: a dilation catheter movably disposed within the sheath lumen; and 12. The device of claim 11, further comprising a conical tip coupled to a distal end of the dilation catheter and to a distal portion of the expandable portion of the dilator, In the first state, a proximal portion of the expandable portion is contracted radially inward toward the dilatation catheter; and In the second state, the proximal portion of the expandable portion is releasably engaged with the distal region of the sheath, forming a continuous, stepless transition between the sheath and the expandable portion of the expander.

14. 14. The device of claim 13, wherein the dilation catheter is configured to move distally relative to the sheath to transition the expandable portion of the dilator from the second state to the first state.

15. The device of claim 13 , wherein the expandable portion of the expander is biased toward the first condition.

16. 14. The device of claim 13, wherein in the second condition, the distal portion of the expandable portion of the expander engages an outer surface of the distal region of the sheath.

17. 14. The device of claim 13, wherein the device comprises a continuous, stepless transition between the sheath and the expandable portion of the expander when the expandable portion is in the second state.

18. The device of claim 13 , wherein the guidewire lumen extends through the conical tip and the dilatation catheter.

19. 14. The device of claim 13, wherein the sheath is configured to move proximally relative to the expandable portion of the expander when the expandable portion of the expander is in the first state to deploy the shunt in the atrial septum.

20. a hollow catheter movably disposed within the sheath lumen, the hollow catheter sized and shaped to receive the dilatation catheter; 14. The device of claim 13, wherein in the first condition, the proximal portion of the expandable portion of the expander is disposed within a distal region of the hollow catheter.

21. 21. The device of claim 20, wherein the hollow catheter is a PEEK tube.

22. 12. The device of claim 11, wherein the distal region of the sheath is configured to transition between a contracted state and an expanded state, wherein the expandable portion of the expander: a proximal portion coupled to an outer tube movably disposed within the sheath lumen; and The device comprises a conical distal portion coupled to an inner tube movably disposed within the outer tube, whereby the conical distal portion is movable relative to the proximal portion between the second state in which the distal region of the sheath is sandwiched between the proximal portion and the conical distal portion in the contracted state, and the first state in which the distal region of the sheath disengages from the proximal portion and the conical distal portion and transitions to the expanded state.

23. 23. The device of claim 22, wherein the device comprises a continuous, stepless transition between the conical distal portion and the distal region of the sheath when the distal region of the sheath is in the contracted state.

24. 23. The device of claim 22, wherein in the contracted state, the distal region of the sheath comprises a plurality of longitudinal slits arranged circumferentially along the distal region and extending from a distal end of the distal region toward the proximal region of the sheath, and wherein in the expanded state, the distal region of the sheath expands along the plurality of longitudinal slits such that each of the plurality of longitudinal slits comprises a V-shape.

25. 23. The device of claim 22, wherein the distal region of the sheath is biased toward the expanded state.

26. 23. The device of claim 22, wherein the distal region of the sheath comprises a resilient material encapsulated with a biocompatible material.

27. 27. The device of claim 26, wherein the elastic material is superelastic nitinol.

28. 27. The device of claim 26, wherein the biocompatible material is a polyether block amide.

29. 23. The device of claim 22, wherein the guidewire lumen extends through the conical distal portion and the inner tube.

30. 12. The device of claim 11, wherein the expandable portion of the dilator comprises an expandable braided tip coupled to an inner tube movably disposed within the sheath lumen, the expandable braided tip configured to transition between the first state and the second state, The device, wherein the distal portion of the shunt is configured to transition between the collapsed delivery state and the expanded deployed state, such that when the expandable braided tip is in the second state, the distal portion of the shunt forms a continuous, stepless transition between the distal portion of the shunt and the expandable braided tip.

31. 31. The device of claim 30, wherein a proximal end of the expandable braided tip is coupled to an outer tube, a distal end of the expandable braided tip is coupled to an inner tube, and the inner tube is movably disposed within the lumen of the outer tube, whereby the proximal end of the expandable braided tip is movable relative to the distal end of the expandable braided tip to transition the expandable braided tip between the first state and the second state.

32. 31. The device of claim 30, wherein the distal portion of the shunt is configured to transition from the collapsed delivery state to the expanded deployed state upon application of heat.

33. 33. The device of claim 32, wherein the sheath further comprises a fluid lumen configured to deliver heated liquid to the distal portion of the shunt.

34. 31. The device of claim 30, wherein the device comprises a continuous, stepless transition between the distal portion of the shunt and the distal region of the sheath when the distal portion of the shunt is in the collapsed delivery state.

35. 31. The device of claim 30, wherein the guidewire lumen extends through the inner tube.

36. 12. The device of claim 11, wherein the distal region of the sheath is configured to transition between a contracted state and an expanded state, the expandable portion of the expander comprises a balloon coupled to a balloon catheter configured to be movably disposed within the sheath lumen, the balloon configured to inflate from the first state to the second state to transition the distal region from the contracted state to the expanded state.

37. 37. The device of claim 36, wherein in the contracted state, the distal region of the sheath comprises a plurality of longitudinal slits defining an opening and arranged circumferentially along the distal region and extending from the opening toward the proximal region of the sheath, and wherein in the expanded state, the distal region of the sheath expands along the plurality of longitudinal slits such that each of the plurality of longitudinal slits comprises a V-shape; The device wherein the distal tip of the balloon extends through the opening and is configured to form a continuous, stepless transition between the balloon and the distal region of the sheath.

38. 38. The device of claim 37, wherein the plurality of longitudinal slits define a plurality of fingers in the distal region, and a distal end of each of the plurality of fingers comprises a rounded shape.

39. 37. The device of claim 36, wherein the distal region of the sheath comprises a shape memory material configured such that the distal region returns to the contracted state upon exposure to heat.

40. 12. The device of claim 11, wherein the expandable portion of the dilator comprises a balloon coupled to a balloon catheter configured to be movably disposed within the sheath lumen, the balloon configured to transition between the first state and the second state adjacent the distal region to form a continuous, stepless transition between the balloon and the distal region of the sheath.

41. 41. The device of claim 40, further comprising a pusher slidably disposed within the sheath lumen, the pusher comprising a pusher lumen sized and shaped to slidably receive the balloon catheter therethrough, and a distal end configured to engage a proximal portion of the shunt in the collapsed delivery state, thereby moving the shunt distally relative to the sheath.

42. 41. The device of claim 40, further comprising a release knot slidably disposed within the sheath lumen, the release knot releasably engaging the shunt via a hitch knot, wherein pulling a first end of the release knot releases the release knot from the shunt, and pulling a second end of the release knot retracts the shunt proximally within the sheath lumen, thereby partially retrieving the shunt.

43. 43. The apparatus of claim 42, wherein the hitch knot comprises a Painta hitch knot or a Quick Tie and Release (QTaR) hitch knot.

44. 43. The device of claim 42, wherein the release knot is configured to be releasably engaged with a proximal portion of the shunt.

45. 45. The device of claim 44, wherein the first and second ends of the release knot pass through a central passage of the shunt toward the intermediate portion of the shunt, form a loop around the outer surface of the intermediate portion of the shunt, and return toward the hitch knot, whereby pulling the second end of the release knot transitions the shunt to the collapsed delivery state.

46. 43. The device of claim 42, wherein the release knot is configured to releasably engage an intermediate portion of the shunt, and wherein the first and second ends of the release knot form a loop that circumferentially surrounds the outer surface of the intermediate portion of the shunt, whereby pulling the second end of the release knot transitions the shunt to the collapsed delivery state.

47. 41. The device of claim 40, wherein the balloon is in a deflated configuration to allow deployment of the shunt through the distal region of the sheath.

48. 41. The apparatus of claim 40, wherein the balloon catheter comprises a fluid lumen configured to fluidly couple the balloon to a fluid source.

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