Systems and methods for radiographic monitoring of shunts

Information

  • Patent Grant
  • 12213817
  • Patent Number
    12,213,817
  • Date Filed
    Friday, April 23, 2021
    4 years ago
  • Date Issued
    Tuesday, February 4, 2025
    3 months ago
Abstract
The present technology relates to interatrial shunting systems and methods. In some embodiments, the present technology includes a method for monitoring a shunting element implanted in a patient and having a lumen fluidly coupling cavities of the patient's heart. The method can comprise obtaining first and second radiographic images of at least two radiopaque elements associated with the lumen of the shunting element. A spatial relationship between the radiopaque elements varies according to a size of the lumen. The first radiographic image can be taken from a first viewing angle and the second radiographic image can be taken from a second viewing angle generally orthonormal to the first viewing angle. The method also includes determining the size of the lumen based, at least in part. on locations of the radiopaque elements in the first and second radiographic images.
Description
TECHNICAL FIELD

The present technology generally relates to implantable medical devices and, in various aspects, to methods for monitoring implantable interatrial systems for selectively controlling blood flow between cavities of a patient's heart.


BACKGROUND

Heart failure is a medical condition associated with the inability of the heart to effectively pump blood to the body. Heart failure affects millions of people worldwide, and may arise from multiple root causes, but is generally associated with myocardial stiffening, myocardial shape remodeling, and/or abnormal cardiovascular dynamics. Chronic heart failure is a progressive disease that worsens considerably over time. Initially, the body's autonomic nervous system adapts to heart failure by altering the sympathetic and parasympathetic balance. While these adaptations are helpful in the short-term, over a longer period of time they serve to make the disease worse.


Heart failure (HF) is a medical term that includes both heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF). The prognosis with both HFpEF and HFrEF is poor; one-year mortality is 26% and 22%, respectively, according to one epidemiology study. In spite of the high prevalence of HFpEF, there remain limited options for HFpEF patients. Pharmacological therapies have been shown to impact mortality in HFrEF patients, but there are no similarly-effective evidence-based pharmacotherapies for treating HFpEF patients. Current practice is to manage and support patients while their health continues to decline. Moreover, people may live unknowingly with heart failure until treatment options are limited. For example, a patient with HFpEF may not be symptomatic until the heart failure disease has progressed to the late stages or the patient presents with comorbidities.


A common symptom among heart failure patients is elevated left atrial pressure. In the past, clinicians have treated patients with elevated left atrial pressure by creating a shunt between the left and right atria using a blade or balloon septostomy. The shunt decompresses the left atrium (LA) by relieving pressure to the right atrium (RA) and systemic veins. Over time, however, the shunt typically will close or reduce in diameter. More recently, percutaneous interatrial shunt devices have been developed which have been shown to effectively reduce left atrial pressure. However, these percutaneous devices generally have an annular passage with a fixed diameter which fails to account for a patient's changing physiology and condition. For this reason, existing percutaneous shunt devices may have a diminishing clinical effect after a period of time. Many existing percutaneous shunt devices typically are also only available in a single size that may work well for one patient but not another. Also, sometimes the amount of shunting created during the initial procedure is later determined to be less than optimal months after implantation. Accordingly, there is a need for improved devices, systems, and methods for treating heart failure patients, particularly those with elevated left atrial pressure.





BRIEF DESCRIPTION OF THE DRAWINGS


FIG. 1 is a schematic illustration of an interatrial device implanted in a heart and configured in accordance with an embodiment of the present technology.



FIG. 2 is a perspective view of an interatrial shunting system configured in accordance with an embodiment of the present technology.



FIG. 3 is a block diagram illustrating a method for monitoring an interatrial shunting system configured in accordance with an embodiment of the present technology.



FIGS. 4A-4D illustrate calculation of lumen diameter from radiographic images in accordance with an embodiment of the present technology.





DETAILED DESCRIPTION

The present technology is generally directed to systems and methods for monitoring interatrial shunting systems. A system configured in accordance with an embodiment of the present technology can include, for example, a shunting element implantable into a patient at or adjacent to a septal wall. The shunting element can include a lumen fluidly connecting cavities of the patient's heart (e.g., the LA and the RA) to facilitate blood flow therebetween. The geometry (e.g., size and/or shape) of the lumen can be selectively adjustable (e.g., non-invasively adjustable) to control the amount of blood flow therethrough.


In some embodiments, the shunting element includes one or more radiopaque elements associated with the lumen to allow for non-invasive monitoring of the lumen geometry. For example, to determine the size of the lumen (e.g., before, during, and/or after adjusting the lumen), the clinician can obtain radiographic images of the shunting element and the radiopaque elements from multiple viewing angles (e.g., orthogonal and/or orthonormal viewing angles). Subsequently, the size of the lumen can be calculated based on the locations of the radiopaque elements in the images, the locations of the radiopaque elements relative to the lumen, the viewing angles from which the images were taken, and/or scaling information for the images. The present technology is expected to improve treatment efficacy by allowing the clinician to monitor lumen geometry, determine whether lumen adjustments would be beneficial, and/or confirm whether lumen adjustments were successful.


The terminology used in the description presented below is intended to be interpreted in its broadest reasonable manner, even though it is being used in conjunction with a detailed description of certain specific embodiments of the present technology. Certain terms may even be emphasized below; however, any terminology intended to be interpreted in any restricted manner will be overtly and specifically defined as such in this Detailed Description section. Additionally, the present technology can include other embodiments that are within the scope of the examples but are not described in detail with respect to FIGS. 1-4D.


Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present technology. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features or characteristics may be combined in any suitable manner in one or more embodiments.


Reference throughout this specification to relative terms such as, for example, “generally,” “approximately,” and “about” are used herein to mean the stated value plus or minus 10%.


As used herein, the terms “interatrial device,” “interatrial shunt device,” “IAD,” “IASD,” “interatrial shunt,” and “shunt” are used interchangeably to refer to a device that, in at least one configuration, includes a shunting element that provides a blood flow between a first region (e.g., a LA of a heart) and a second region (e.g., a RA or coronary sinus of the heart) of a patient. Although described in terms of a shunt between the atria, namely the left and right atria, one will appreciate that the technology may be applied equally to devices positioned between other chambers and passages of the heart, or between other parts of the cardiovascular system or other system. For example, any of the shunts described herein, including those referred to as “interatrial,” may be nevertheless used and/or modified to shunt between the LA and the coronary sinus, or between the right pulmonary vein and the superior vena cava. Moreover, while the disclosure herein primarily describes shunting blood from the LA to the RA, the present technology can be readily adapted to shunt blood from the RA to the LA to treat certain conditions, such as pulmonary hypertension. For example, mirror images of embodiments, or in some cases identical embodiments, used to shunt blood from the LA to the RA can be used to shunt blood from the RA to the LA in certain patients.


Although certain embodiments herein are described with respect to radiopaque elements configured to be visualized via radiographic imaging, it will be appreciated that the principles of the present technology can be adapted for use with other imaging methods. For example, the present technology can alternatively or additionally use markers with selective echogenicity (e.g., largely hyperechoic) configured to be visualized through ultrasound imaging and related imaging methods.


The headings provided herein are for convenience only and do not interpret the scope or meaning of the claimed present technology.


A. Interatrial Shunts for Treatment of Heart Failure


Heart failure can be classified into one of at least two categories based upon the ejection fraction a patient experiences: (1) HFpEF, historically referred to as diastolic heart failure or (2) HFrEF, historically referred to as systolic heart failure. One definition of HFrEF is a left ventricular ejection fraction lower than 35%-40%. Though related, the underlying pathophysiology and the treatment regimens for each heart failure classification may vary considerably. For example, while there are established pharmaceutical therapies that can help treat the symptoms of HFrEF, and at times slow or reverse the progression of the disease, there are limited available pharmaceutical therapies for HFpEF with only questionable efficacy.


In heart failure patients, abnormal function in the left ventricle (LV) leads to pressure build-up in the LA. This leads directly to higher pressures in the pulmonary venous system, which feeds the LA. Elevated pulmonary venous pressures push fluid out of capillaries and into the lungs. This fluid build-up leads to pulmonary congestion and many of the symptoms of heart failure, including shortness of breath and signs of exertion with even mild physical activity. Risk factors for HF include renal dysfunction, hypertension, hyperlipidemia, diabetes, smoking, obesity, old age, and obstructive sleep apnea. HF patients can have increased stiffness of the LV which causes a decrease in left ventricular relaxation during diastole resulting in increased pressure and inadequate filling of the ventricle. HF patients may also have an increased risk for atrial fibrillation and pulmonary hypertension, and typically have other comorbidities that can complicate treatment options.


Interatrial shunts have recently been proposed as a way to reduce elevated left atrial pressure, and this emerging class of cardiovascular therapeutic interventions has been demonstrated to have significant clinical promise. FIG. 1 shows the conventional placement of a shunt in the septal wall between the LA and RA. Most conventional interatrial shunts (e.g., shunt 10) involve creating a hole or inserting a structure with a lumen into the atrial septal wall, thereby creating a fluid communication pathway between the LA and the RA. As such, elevated left atrial pressure may be partially relieved by unloading the LA into the RA. In early clinical trials, this approach has been shown to improve symptoms of heart failure.


One challenge with many conventional interatrial shunts is determining the most appropriate size and shape of the shunt lumen. A lumen that is too small may not adequately unload the LA and relieve symptoms; a lumen that is too large may overload the RA and right heart more generally, creating new problems for the patient. Moreover, the relationship between pressure reduction and clinical outcomes and the degree of pressure reduction required for optimized outcomes is still not fully understood, in part because the pathophysiology for HFpEF (and to a lesser extent, HFrEF) is not completely understood. As such, clinicians are forced to take a best guess at selecting the appropriately sized shunt (based on limited clinical evidence) and generally cannot adjust the sizing over time. Worse, clinicians must select the size of the shunt based on general factors (e.g., the size of the patient's anatomical structures, the patient's hemodynamic measurements taken at one snapshot in time, etc.) and/or the design of available devices rather than the individual patient's health and anticipated response. With many such traditional devices, the clinician does not have the ability to adjust or titrate the therapy once the device is implanted, for example, in response to changing patient conditions such as progression of disease. By contrast, interatrial shunting systems configured in accordance with embodiments of the present technology allow a clinician to select shunt size—perioperatively or post-implant—based on the patient and, as discussed above, allow for non-invasive monitoring of lumen geometry to determine whether lumen adjustments would be beneficial and/or confirm whether lumen adjustments were successful.


B. Select Embodiments of Methods for Monitoring Interatrial Shunting Systems


As provided above, the present technology is generally directed to methods for monitoring interatrial shunting systems. Such systems include a shunting element implantable into a patient at or adjacent to a septal wall. The shunting element can include a lumen fluidly connecting the LA and the RA of the patient to facilitate blood flow therebetween. In some embodiments, the lumen is invasively or non-invasively adjustable to selectively control blood flow between the LA and the RA. To allow for monitoring of the lumen geometry (e.g., to confirm whether a desired adjustment was successfully achieved, determine whether an adjustment would be beneficial, etc.), the shunting element can include at least two radiopaque elements positioned such that the spatial relationship between the radiopaque elements varies based on the lumen geometry. Accordingly, the clinician can determine the lumen geometry by taking radiographic images of the radiopaque elements from different viewing angles and calculating the spatial relationship between the radiopaque elements from the image data.



FIG. 2 is a perspective view of an interatrial shunting system 200 configured in accordance with an embodiment of the present technology. The system 200 includes a shunting element 202 defining a lumen 204 therethrough. When implanted in the septal wall (not shown) of a patient, the shunting element 202 can fluidly connect the LA (not shown) and the RA (not shown) via the lumen 204. In some embodiments, the geometry (e.g., size and/or shape) of the lumen 204 is adjustable (e.g., invasively or non-invasively adjustable) to alter the amount of fluid flow through the shunting element 202, as described in greater detail below.


The shunting element 202 can be secured to the septal wall via one or more first anchoring elements 206a and one or more second anchoring elements 206b. Anchoring elements 206a/206b may assume a variety of shapes, such as struts, flanges, coils, braids, cones, etc. In some embodiments, the first anchoring elements 206a are configured to engage a portion of the septal wall facing a first heart chamber (e.g., the RA) and the second anchoring elements 206b are configured to engage a portion of the septal wall facing a second heart chamber (e.g., the LA). In other embodiments the shunting element 202 is anchored in place using anchoring elements positioned on only one side of the septal wall. Optionally, a single anchoring element may be used on one or both sides of the septal wall. In yet other embodiments, the system 200 does not include first and second anchoring elements 206a-b and is instead secured in place by exerting a radially outward pressure against the septal wall or by other suitable mechanisms.


The system 200 can include a first membrane 208a and a second membrane 208b operably coupled to the shunting element 202 (e.g., carried by, connected to, and/or at least partially covering the shunting element 202). In the illustrated embodiment, for example, the first membrane 208a is connected to an end portion of the shunting element 202 near the lumen 204 and the first anchoring elements 206a, while the second membrane 208b is connected to the remaining portions of the shunting element 202 and to the second anchoring elements 206b. The membranes 208a-b can be flexible and can be made of a material that is impermeable to or otherwise resists blood flow therethrough. Optionally, the material can be an anti-thrombogenic material. In some embodiments, the membranes 208a-b are made of a thin, elastic material such as a polymer. For example, the membranes 208a-b can be made of polytetrafluoroethylene (PTFE), expanded PTFE (ePTFE), silicone, nylon, polyethylene terephthalate (PET), polyether block amide (pebax), polyurethane, blends or combinations of these materials, or other suitable materials. It will be appreciated that the first and second membranes 208a-b can be configured in many different ways. In other embodiments, for example, the first and second membranes 208a-b can be connected to different portions of the shunting element 202. In further embodiments, the first and second membranes 208a-b can be combined into a single unitary membrane. Optionally, one or both of the first and second membranes 208a-b can be omitted.


In some embodiments, the system 200 includes a flow control mechanism 210 configured to change a size, shape, and/or other characteristic of the shunting element 202 to selectively modulate the flow of fluid through the lumen 204. For example, the flow control mechanism 210 can be configured to selectively increase and/or decrease a size (e.g., diameter) of the lumen 204 in response to an input. In other embodiments, the flow control mechanism 210 is configured to otherwise affect the geometry (e.g., size and/or shape) or another characteristic of the lumen 204. In the illustrated embodiment, for example, the flow control mechanism 210 includes an annular structure 212 (e.g., a band, ring, frame, etc.) surrounding the lumen 204. The portions of the first membrane 208a around the perimeter of the lumen 204 can be coupled to the annular structure 212. As a result, the geometry of the lumen 204 can be altered directly or indirectly by adjusting the geometry of the annular structure 212 (e.g., by deforming, deflecting, or otherwise changing the annular structure 212 from a first configuration to a second configuration). The changes in the geometry of the annular structure 212 can deform (e.g., stretch, compress) or otherwise move the portions of the first membrane 208a surrounding the lumen 204 thereby altering the geometry of the lumen 204.


In some embodiments, the geometry of the annular structure 212 can be altered directly using mechanical techniques (e.g., dilating with a balloon). Alternatively or in combination, one or more portions of the annular structure 212 can be made of a shape memory material (e.g., nitinol). In such embodiments, for example, changes to the geometry of the annular structure 212 (and therefore the lumen 204) can be induced by applying external stresses to the annular structure 212 and/or by inducing internal stresses in the annular structure 212 via the application of energy (e.g., heating the annular structure 212 beyond a transition temperature that results in at least a temporary alteration of the material state).


Alternatively or in combination, the system 200 can include other types of flow control mechanisms configured to selectively change the geometry of the lumen 204. In some embodiments, for example, the flow control mechanism 210 can include one or more motors, such as electromagnetic motors, implanted battery and mechanical motors, MEMS motors, micro brushless DC motors, piezoelectric based motors, solenoids, and other motors. In other embodiments, the flow control mechanism 210 includes one or more shape memory elements. A shape memory element can be configured to change in shape (e.g., transform between a first configuration and a second configuration) in response to a stimulus (e.g., heat or mechanical loading) as is known to those of skill in the art. In embodiments of the present technology that utilize heat or another form of energy applied to a shape memory element or another component of the system 200, the energy/heat can be applied both invasively (e.g., via a catheter delivering laser, radiofrequency, or another form of energy, via an internal stored energy source such as a supercapacitor, etc.), non-invasively (e.g., using radiofrequency energy delivered by a transmitter outside of the body, by focused ultrasound, etc.), or through a combination of these methods.


The system 200 further includes a first radiopaque element 214a and a second radiopaque element 214b (shown schematically) carried by the shunting element 202. The radiopaque elements 214a-b can be made of any material having sufficient density to reduce or inhibit the transmission of X-rays or other forms of electromagnetic radiation so that the radiopaque elements 214a-b can be visualized using radiographic imaging techniques (e.g., X-ray imaging). For example, the radiopaque elements 214a-b can be made of a metal (e.g., tantalum, gold, platinum), a polymer, a composite, a dye, a contrast medium (e.g., barium sulfate), or any other suitable material known to those of skill in the art. In some embodiments, the system 200 may alternatively or in combination contain markers with selective echogenicity (e.g., largely hyperechoic) to enable visualization through ultrasonic and related imaging methods.


The geometry (e.g., size, shape) of the radiopaque elements 214a-b can be configured in many different ways. For example, the radiopaque elements 214a-b can be bands, markers, discs, rivets, fasteners, beads, bearings, or any other structure suitable for incorporation in the system 200. The shape of the radiopaque elements 214a-b can be selected to facilitate visualization in radiographic images. In some embodiments, for example, the radiopaque elements 214a-b each have a spherical, circular, or cylindrical shape so that at least one dimension (e.g., diameter) of the element is fixed and readily ascertainable even when imaged from different viewing angles (e.g., for determining scaling as described in greater detail below). Alternatively, the radiopaque elements 214a-b can have another shape (e.g., square, rectangular, triangular, elliptical, polygonal, curvilinear, etc.). In some embodiments, some or all of the radiopaque elements 214a-b can have different sizes and/or shapes so they can be distinguished from each other.


In some embodiments, some or all of the radiopaque elements 214a-b are coupled to another component of the system 200 via adhesives, fasteners, bonding, etc. In the illustrated embodiment, for example, the radiopaque elements 214a-b can be attached to one or more of the shunting element 202, anchoring elements 206a-b, membranes 208a-b, flow control mechanism 210, or annular structure 212. Alternatively or in combination, some or all of the radiopaque elements 214a-b can be integrally formed with or otherwise be a part of another component. For example, one or more portions of the first membrane 208a surrounding the lumen 204 can be made from or otherwise include a radiopaque material. Radiopaque materials can be incorporated in the components of the system 200 in many different ways, such as by coating, printing, impregnating, or other techniques known to those of skill in the art. Optionally, in some embodiments the radiopaque elements 214a-b are not discrete components, but instead are features of a continuous radiopaque component that can be distinguished from each other in images. For example, the annular structure 212 can be made from a radiopaque material and can include distinct features (e.g., peaks, rivets, points, etc.) that serve as the radiopaque elements 214a-b for purposes of the methods described herein.


The radiopaque elements 214a-b can be operably coupled to and/or associated with the lumen 204 such that changes in the geometry of the lumen 204 produce corresponding changes in the spatial relationship of the radiopaque elements 214a-b to each other. For example, the system 200 can include a structure at least partially surrounding the lumen 204 (e.g., a frame, stent, membrane, ring, band, etc.) such that changes in the geometry of the structure correlate to changes in the geometry of the lumen. The radiopaque elements 214a-b can be included in, coupled to, or otherwise associated with the structure so that changes in the geometry of the structure alter the positions of the radiopaque elements 214a-b in one or more dimensions. In the illustrated embodiment, for example, the radiopaque elements 214a-b are positioned at or near the perimeter of the lumen 204 (e.g., attached to or incorporated into the first membrane 208a). The radiopaque elements 214a-b can be at diametrically opposed locations relative to the lumen 204 such that the distance D between the radiopaque elements 214a-b corresponds directly to a dimension (e.g., a diameter) of the lumen 204. As a result, the dimension of the lumen 204 can be determined based on the spacing between the radiopaque elements 214a-b in radiographic images, as described in greater detail below.


Although FIG. 2 illustrates two radiopaque elements 214a-b, in other embodiments the system 200 can include a different number of radiopaque elements 214, such as one, three, four, five, or more. In embodiments where the system 200 includes a plurality of radiopaque elements 214, the radiopaque elements 214 can be distributed across different locations of the system 200 (e.g., coupled to or included in the shunting element 202, anchoring elements 206a-b, membranes 208a-b, flow control mechanism 210, annular structure 212, etc.). The radiopaque elements 214 can be spaced apart from each other in a defined and precise spatial relationship to allow the lumen geometry to be reconstructed from radiographic images of the radiopaque elements 214, as described further below. For example, three or more radiopaque elements 214 can be spaced around the perimeter of the lumen 204 (e.g., with paired elements at diametrically opposite locations). The use of multiple radiopaque elements 214 is expected to provide redundancy that improves the accuracy and precision of the measurement techniques described herein.


In some embodiments, the system 200 can optionally include one or more calibration elements 216. As described in detail below with respect to FIG. 3, the one or more calibration elements 216 can be used to calculate a scaling factor to more accurately and precisely measure a dimension between the radiopaque elements 241a-b. Although shown as positioned on a first anchoring element 206a, the calibration elements 216 can alternatively be positioned on other portions of the system 200, such as within a housing (not shown) that carries a power supply or other electronic components of the system 200. The calibration elements 216 can also be spaced apart from the system 200, and/or positioned external to the patient.



FIG. 3 is a block diagram illustrating a method 300 for monitoring an interatrial shunting system configured in accordance with an embodiment of the present technology. The method 300 can be applied to any interatrial shunting system including radiopaque elements, such as the system 200 described with respect to FIG. 2 or other suitable systems. In some embodiments, some or all of the steps of the method 300 are performed by a processor configured to execute instructions stored in a memory and/or a non-transitory computer-readable medium for performing the operations described herein. For example, the method 300 can be performed by a computing system configured to receive radiographic images and, based on the received images, determine a lumen size. In other embodiments, however, the method 300 may be implemented by other suitable mechanisms, systems, or devices.


Beginning at block 310, the method 300 includes receiving a first radiographic image of at least two radiopaque elements from a first viewing angle. The method continues with receiving a second radiographic image of the at least two radiopaque elements from a second viewing angle (block 320). The at least two radiopaque elements can be identical or generally similar to the radiopaque elements 214a-b described with respect to FIG. 2. For example, the radiopaque elements can be operably coupled to and/or associated with a lumen of the shunting element (e.g., positioned at or near the perimeter of the lumen). The radiopaque elements can have a specified spatial relationship with each other (e.g., diametrically opposite locations) that allows the lumen geometry to be reconstructed from the first and second radiographic images.


The first and second radiographic images can be any type of image data (e.g., still images, video) obtained via radiographic imaging techniques, such as an X-ray (e.g., a chest X-ray). Radiographic imaging techniques suitable for use with the embodiments herein include, but are not limited to, fluoroscopy (e.g., biplane fluoroscopy), C-arm X-ray imaging, and computed tomography (CT) imaging. In some embodiments, the first and second radiographic images are obtained by a suitable radiographic imaging device and transmitted to a computing device or system for subsequent processing and analysis. In embodiments of the system that include echogenic markers, the radiographic images may alternatively or in combination include ultrasonic images.


A radiographic imaging device can include at least one radiation source (e.g., an X-ray source) that is oriented relative to the patient's body to produce a radiographic image of the body along a corresponding viewing angle. In the method 300, the first radiographic image can be taken from a first viewing angle and the second radiographic image can be taken from a second viewing angle. The first and second viewing angles can be different viewing angles, e.g., the first viewing angle is a posterior-anterior viewing angle and the second viewing angle is a lateral viewing angle. In some embodiments, the first and second viewing angles are orthogonal or generally orthogonal such that they differ from each other by approximately 90 degrees. In some embodiments, the first and second viewing angles are orthonormal or generally orthonormal. In other embodiments the first and second viewing angles may not be orthogonal or orthonormal to each other.


The first and second radiographic images can be obtained in many different ways. For example, the first and second radiographic images can be taken by a radiographic imaging device having multiple radiation sources for taking images from multiple viewing angles (e.g., biplane fluoroscopy). In such embodiments, the first radiographic image can be obtained using a first radiation source oriented along the first viewing angle and the second radiographic image can be obtained using a second radiation source oriented along the second viewing angle. As another example, the first and second radiographic images can be taken by an imaging device having a single radiation source movable between a plurality of different orientations relative to the patient (e.g., a C-arm). In such embodiments, the first radiographic image can be obtained while the radiation source is oriented along the first viewing angle. The radiation source can then be moved to the second viewing angle to obtain the second radiographic image.


In some embodiments, the first and second radiographic images are obtained while the patient remains generally stationary. In such embodiments, radiographic images can be obtained by multiple radiation sources oriented along different viewing angles and/or by a single radiation source that is movable between different viewing angles. This approach is expected to improve the accuracy of capturing images at the desired viewing angles (e.g., orthonormal viewing angles). In other embodiments, however, the radiation source(s) can remain fixed while the patient is moved to different orientations. For example, the patient can be placed in a first orientation relative to the radiation source(s) to produce the first radiographic image, then subsequently moved to a second orientation to produce the second radiographic image.


In some embodiments, the first and second radiographic images are gated to reduce or prevent bodily movements of the patient (e.g., movements of the heart and/or lungs) from affecting measurement accuracy. For example, respiratory and/or cardiac movements can affect the position of the patient's body relative to the radiation source(s) as well as the position and geometry of implanted components (e.g., the shunting element, the lumen, the radiopaque elements). To limit the effect of these movements, the radiographic images can be gated based on the patient's respiratory cycle and/or cardiac cycle so that that the locations of the implanted components remain identical or generally similar across different images.


The method 300 further includes determining a lumen size based at least in part on the first and second radiographic images (block 330). In some embodiments, the first and second radiographic images each provide a two-dimensional (2D) projection of the three-dimensional (3D) locations of the radiopaque elements within the patient's body. Each radiographic image can be used to calculate various 2D measurements of the radiopaque elements. For example, the radiographic images can be used to calculate 2D locations or coordinates of each radiopaque element relative to a plane within a reference coordinate system (e.g., a coordinate system generally aligned with the patient's anatomical axes). The collective 2D measurements of the radiopaque elements in the images can be used to calculate the corresponding 3D spatial relationship of the radiopaque elements in the patient, which in turn is used to determine the geometry of the lumen (e.g., a lumen diameter). For example, in embodiments where a pair of radiopaque elements are positioned at diametrically opposed locations around the lumen perimeter, the 2D measurements can be used to calculate the 3D distance between the elements, which corresponds to a lumen diameter. Additional details of techniques for determining the lumen size are described with respect to FIGS. 4A-4D below.


In some embodiments, the method 300 also optionally includes calculating a scaling factor for converting 2D distances in the radiographic images (e.g., distances expressed in pixels) to actual 3D distances in the patient's body (e.g., distances expressed in mm). For example, to calculate the scaling factor, the sizes of the radiopaque elements in the radiographic images can be measured and compared to the known actual sizes of the radiopaque elements. Alternatively or in combination, the scaling factor can be calculated based on the size of at least one calibration element shown in the radiographic images. The calibration element(s) can have a spherical, circular, or cylindrical shape so that at least one dimension (e.g., diameter) of the calibration element(s) remains generally fixed when imaged from different viewing angles. In some embodiments, one or more calibration elements are located in the patient's body. For example, the calibration element(s) can be carried by the shunting element (e.g., the calibration element(s) 216 shown in FIG. 2, which may optionally be positioned within a housing of the system 200 for a power supply or other electronic components). In other embodiments, the calibration element(s) can be separate from but located near the shunting element, or can be located at a different region within the patient's body. In further embodiments, the calibration element(s) can be external to the patient's body (e.g., a ball bearing taped to the patient's body). The size of the calibration element(s) in the radiographic images can be measured and compared to the known actual size of the calibration element(s) to determine the scaling factor.


It will be appreciated that the method 300 can be implemented in many different ways. In some embodiments, for example, the method 300 further includes obtaining and/or receiving additional radiographic images of the radiopaque elements. For example, rather than taking a single radiographic image at each viewing angle, multiple images can be taken at each viewing angle, and the measurements from those images can be averaged or otherwise combined to improve accuracy. As another example, a third radiographic image can be obtained at a third viewing angle different from the first and second viewing angles and used to determine lumen size.


In some embodiments, the method 300 is performed before, during, and/or after a shunt adjustment operation. For example, a clinician can use the techniques described herein to non-invasively determine the lumen geometry of an implanted shunting element before making any adjustments to the shunting element, e.g., to assess the current state of the shunting element, determine whether the shunting element was implanted properly, evaluate whether adjustments would be beneficial, etc. The techniques herein can also be used for radiographic monitoring during a shunt adjustment procedure, e.g., to provide fluoroscopic guidance for invasive adjustments. Optionally, the techniques herein can also be used to measure the lumen geometry after the adjustment procedure has been completed, e.g., to confirm whether the intended adjustments were successfully achieved, assess whether additional adjustments would be beneficial, etc.


Optionally, the method 300 can be repeated multiple times to obtain radiographic images and determine the lumen size at multiple time points. For example, a first set of radiographic images can be obtained at a first time point to determine the lumen size at the first time point (e.g., before making an adjustment to a shunting element, during an initial phase of treatment, etc.). After a desired time period has passed (e.g., hours, days, weeks, months, years, etc.), a second set of radiographic images can be obtained at a second time point to determine the lumen size at the second time point (e.g., after making an adjustment to a shunting element, during a subsequent phase of treatment, etc.). This process can be repeated to determine the lumen size at as many additional time points as desired. The lumen sizes across the different time points can be compared to each other, e.g., to confirm whether an adjustment was successful, track the size of the lumen over time, detect whether undesirable changes in the lumen size have occurred. In some embodiments, the comparison of lumen sizes over time is used to evaluate the patient's condition (e.g., physiological state, health status, etc.).


Optionally, the measured lumen size can be compared to an estimated lumen size. In embodiments where adjustments to the shunting element are made via an implanted flow control mechanism (e.g., the flow control mechanism 210 of FIG. 2), the estimated lumen size can be calculated based at least partly on the configuration of the flow control mechanism (e.g., position, orientation, size, etc.). By comparing the measured and estimated lumen sizes, the clinician can assess whether the flow control mechanism was able to successfully adjust the shunting element and/or whether additional adjustments should be performed to achieve a desired lumen size. Optionally, the differences between the measured and estimated lumen sizes can be tracked and analyzed over time (e.g., via suitable software or other devices or techniques) to monitor and assess the condition of the patient and/or the shunting element.



FIGS. 4A-4D illustrate calculation of lumen diameter from radiographic images in accordance with an embodiment of the present technology. More specifically, FIG. 4A illustrates a first radiographic image 400a of first and second radiopaque elements 402a-b, FIG. 4B illustrates a second radiographic image 400b of the radiopaque elements 402a-b, FIG. 4C illustrates 2D measurements of the radiopaque elements 402a-b in the first radiographic image 400a, and FIG. 4D illustrates 2D measurements of the radiopaque elements 402a-b in the second radiographic image 400b.


Referring first to FIGS. 4A and 4B together, the first radiographic image 400a includes image data of the two radiopaque elements 402a-b from a first viewing angle (e.g., a posterior-anterior viewing angle), and the second radiographic image 400b includes image data of the two radiopaque elements 402a-b from a second viewing angle orthonormal to the first viewing angle (e.g., a lateral viewing angle). The radiopaque elements 402a-b can be positioned at diametrically opposite locations near a perimeter of a lumen of a shunting element, as previously described. As can be seen in FIGS. 4A and 4B, the radiographic images 400a-b each provide a 2D projection of the 3D locations of the radiopaque elements 402a-b in the patient's body.


Referring next to FIGS. 4C and 4D together, the locations of the radiopaque elements 402a-b in the radiographic images 400a-b can be determined with respect to a reference coordinate system 404. The axes of the reference coordinate system 404 (e.g., x, y, z axes) can be configured to be generally aligned with the anatomical axes of the patient's body (e.g., left (L)-to-right (R), superior (S)-to-inferior (I), and anterior (A)-to-posterior (P) axes—shown in FIGS. 4A and 4B). In other embodiments, however, the reference coordinate system 404 can be aligned with other anatomical axes, or can be aligned with an off-axis imaging plane (e.g., right anterior oblique (RAO)-to-left anterior oblique (LAO)). In some embodiments, at least one axis of the reference coordinate system 404 is collinear with the axis of rotation between the first and second radiographic images 400a-b. In the illustrated embodiment, for example, the y-axis is collinear with the axis of rotation (e.g., the SI axis) and is coplanar with the patient's sagittal and coronal planes.


Referring to FIG. 4C, for the first radiographic image 400a, a line Y1 can be drawn from the location of the first radiopaque element 402a in a direction parallel to the axis of rotation (e.g., parallel to the y-axis of the reference coordinate system 404 as indicated by the arrow along line Y1). A line X1 can be drawn from the second radiopaque element 402b in a direction perpendicular to line Y1 (e.g., parallel to the x-axis of the reference coordinate system 404 as indicated by the arrow along line X1). Lines X1 and Y1 can terminate at their point of intersection. The lengths of lines X1 and Y1 can provide a first set of 2D measurements for the radiopaque elements 402a-b.


Referring to FIG. 4D, for the second radiographic image 400b, a line Y2 can be drawn from the location of the first radiopaque element 402a in a direction parallel to the axis of rotation (e.g., parallel to the y-axis of the reference coordinate system 404 as indicated by the arrow along line Y2). A line Z1 can be drawn from the second radiopaque element 402b in a direction perpendicular to line Y2 (e.g., parallel to the z-axis of the reference coordinate system 404 as indicated by the arrow along line Z1). Lines Z1 and Y2 can terminate at their point of intersection. The lengths of lines Z1 and Y2 can provide a second set of 2D measurements for the radiopaque elements 402a-b.


The 3D spatial relationship between the radiopaque elements 402a-b can be reconstructed based on the first and second sets of 2D measurements (e.g., X1, Y1, Z1, Y2). In the illustrated embodiment, X1 corresponds to the x-distance between the radiopaque elements 402a-b, Y1 and/or Y2 correspond to the y-distance, and Z1 corresponds to the z-distance. In some embodiments, either Y1, Y2, or both can be used to calculate the y-distance. As can be seen in FIGS. 4C and 4D, because lines Y1 and Y2 are parallel to the axis of rotation, the lengths of lines Y1 and Y2 are expected to be identical. However, Y1 and Y2 may not be identical if the first and second radiographic images 400a-b are not exactly orthonormal to each other, e.g., due to variations in patient posture, respiration, cardiac biomechanics, and/or the rotational precision of the imaging device. Accordingly, in some embodiments, Y1 and Y2 are averaged to improve the measurement accuracy. The 3D distance between the radiopaque elements 402a-b, D, which corresponds to the lumen diameter, can then be calculated using the following equation:






D
=



X
1
2

+

Z
1
2

+


(



Y
1

+

Y
2


2

)

2







Although FIGS. 4A-4D illustrate a lumen size calculation performed using two radiographic images 400a-b and two radiopaque elements 402a-b, one of skill in the art will appreciate that the principles described herein can be adapted for a different number of radiographic images and/or radiopaque elements. Moreover, although the calculation described with respect to FIGS. 4A-4D involves two radiopaque elements 402a-b positioned at diametrically opposed locations around the lumen, the present technology can be adapted for use with other arrangements of radiopaque elements relative to the lumen.


As one of skill in the art will appreciate from the disclosure herein, various features of the methods and systems described above can be omitted without deviating from the scope of the present technology. Likewise, additional features not explicitly described above may be added to the methods and systems without deviating from the scope of the present technology. Accordingly, the methods and systems described herein are not limited to those configurations expressly identified, but rather encompasses variations and alterations of the described methods and systems. Moreover, the following paragraphs provide additional description of various aspects of the present technology. One skilled in the art will appreciate that the following aspects can be incorporated into any of the methods and systems described above.


EXAMPLES

Several aspects of the present technology are set forth in the following examples:


1. A method for monitoring a shunting element implanted in a patient and having a lumen fluidly coupling a first body region of the patient and a second body region of the patient, the method comprising:

    • receiving a first radiographic image of at least two radiopaque elements associated with the lumen, wherein a spatial relationship between the at least two radiopaque elements varies according to a size of the lumen, and wherein the first radiographic image is taken from a first viewing angle;
    • receiving a second radiographic image of the at least two radiopaque elements, wherein the second radiographic image is taken from a second viewing angle different than the first viewing angle; and
    • determining the size of the lumen based, at least in part, on locations of the at least two radiopaque elements in the first and second radiographic images.


2. The method of example 1 wherein the second viewing angle is orthogonal to the first viewing angle.


3. The method of example 1 wherein the second viewing angle is orthonormal to the first viewing angle.


4. The method of any of examples 1-3 wherein the at least two radiopaque elements are positioned at or near a perimeter of the lumen.


5. The method of example 4 wherein the at least two radiopaque elements include a first radiopaque element and a second radiopaque element positioned at diametrically opposite locations at or near the perimeter of the lumen.


6. The method of example 4 wherein the at least two radiopaque elements include three or more radiopaque elements spaced around the perimeter of the lumen.


7. The method of any of examples 1-6 wherein the shunting element includes a structure at least partially surrounding the lumen, and wherein the structure includes the at least two radiopaque elements.


8. The method of example 7 wherein the structure comprises one or more of a frame, a stent, a membrane, a ring, or a band.


9. The method of any of examples 1-8 wherein the at least two radiopaque elements comprise bands, markers, discs, rivets, fasteners, or beads.


10. The method of any of examples 1-9 wherein the at least two radiopaque elements each have a spherical, cylindrical, or circular shape.


11. The method of any of examples 1-10 wherein:

    • the first and second radiographic images each include image data of at least one calibration element having a spherical, cylindrical, or circular shape; and
    • the method further comprises determining a scaling factor for the first and second radiographic images based at least in part on the image data of the at least one calibration element.


12. The method of example 11 wherein the at least one calibration element is carried by the shunting element.


13. The method of example 11 wherein the at least one calibration element is external to the patient's body.


14. The method of any of examples 1-13 wherein:

    • the first radiographic image is obtained using a first radiation source oriented along the first viewing angle; and
    • the second radiographic image is obtained using a second radiation source oriented along the second viewing angle.


15. The method of any of examples 1-13 wherein:

    • the first and second radiographic images are obtained using a single radiation source; and
    • the method further comprises moving the single radiation source between the first and second viewing angles to obtain the first and second radiographic images.


16. The method of any of examples 1-15 wherein:

    • the first radiographic image is obtained when the patient is positioned at a first orientation corresponding to the first viewing angle;
    • the second radiographic image is obtained using when the patient is positioned at a second orientation corresponding to the second viewing angle; and
    • the method further comprises moving the patient between the first and second orientations to obtain the first and second radiographic images.


17. The method of any of examples 1-16 wherein the first viewing angle is an anterior-posterior viewing angle and the second viewing angle is a lateral viewing angle.


18. The method of any of examples 1-17, further comprising:

    • receiving a third radiographic image of the at least two radiopaque elements, wherein the third radiographic image is taken at a third viewing angle different from the first and second viewing angles; and
    • determining the size of the lumen based at least in part on locations of the at least two radiopaque elements in the third radiographic image.


19. The method of any of examples 1-18 wherein the first and second radiographic images are gated based on one or more of a respiratory cycle or a cardiac cycle of the patient.


20. The method of any of examples 1-19 wherein determining the size of the lumen comprises:

    • determining two-dimensional measurements of the at least two radiopaque elements in each of the first and second radiographic images; and
    • calculating a three-dimensional distance between the at least two radiopaque elements based on the two-dimensional measurements.


21. The method of any of examples 1-20 wherein the first and second radiographic images are X-ray images.


22. The method of any of examples 1-21 wherein the lumen of the shunting element is selectively adjustable to control fluid flow therethrough.


23. The method of example 22, further comprising adjusting the lumen of the shunting element before, during, and/or after obtaining the first and second radiographic images.


24. The method of any of examples 1-23 wherein the first body region includes a first cavity of a heart of the patient and the second body region includes a second cavity of the heart of the patient, and wherein the first and second cavities of the heart of the patient include: (a) a left atrium and a right atrium, (b) a left ventricle and a right ventricle, or (c) a coronary sinus and the left ventricle.


25. The method of any of examples 1-24 wherein:

    • the first and second radiographic images are obtained at a first time point;
    • the size of the lumen is a first size; and
    • the method further comprises:
      • receiving one or more additional radiographic images of the at least two radiopaque elements obtained at a second time point different from the first time point; and
      • determining a second size of the lumen based, at least in part, on locations of the at least two radiopaque elements in the one or more additional radiographic images.


26. The method of example 25, further comprising comparing the first and second lumen sizes.


27. The method of example 26, further comprising evaluating one or more of a physiological state or health status of the patient based, at least in part, on the comparison of the first and second lumen sizes.


28. A system for monitoring a shunting element implanted in a patient and having a lumen fluidly coupling a first body region of the patient and a second body region of the patient, the system comprising:

    • a processor; and
    • a memory storing instructions that, when executed by the processor, cause the system to perform operations comprising:
      • receiving first radiographic image data of at least two radiopaque elements associated with the lumen, wherein a spatial relationship between the at least two radiopaque elements varies according to a size of the lumen, and wherein the first radiographic image data is taken from a first viewing angle;
      • receiving second radiographic image data of the at least two radiopaque elements, wherein the second radiographic image data is taken from a second viewing angle different than the first viewing angle; and
      • determining the size of the lumen based, at least in part, on locations of the at least two radiopaque elements in the first and second radiographic image data.


29. The system of example 28, further comprising a radiographic imaging device configured to obtain the first and second radiographic image data.


30. The system of example 28 or 29 wherein the second viewing angle is orthogonal to the first viewing angle.


31. The system of example 28 or 29 wherein the second viewing angle is orthonormal to the first viewing angle.


32. The system of any of examples 28-31 wherein the first body region includes a first cavity of a heart of the patient and the second body region includes a second cavity of the heart of the patient, and wherein the first and second cavities of the heart of the patient include: (a) a left atrium and a right atrium, (b) a left ventricle and a right ventricle, or (c) a coronary sinus and the left ventricle.


33. A non-transitory computer-readable medium storing instructions that, when executed by a processor of a system for monitoring a shunting element implanted in a patient and having a lumen fluidly coupling a first body region of the patient and a second body region of the patient, cause the system to perform operations comprising:

    • receiving first radiographic image data of at least two radiopaque elements associated with the lumen, wherein a spatial relationship between the at least two radiopaque elements varies according to a size of the lumen, and wherein the first radiographic image data is taken from a first viewing angle;
    • receiving second radiographic image data of the at least two radiopaque elements, wherein the second radiographic image data is taken from a second viewing angle different than the first viewing angle; and
    • determining the size of the lumen based, at least in part, on locations of the at least two radiopaque elements in the first and second radiographic image data.


34. The non-transitory computer-readable medium of example 33 wherein the second viewing angle is orthogonal to the first viewing angle.


35. The non-transitory computer-readable medium of example 33 wherein the second viewing angle is orthonormal to the first viewing angle.


36. The non-transitory computer-readable medium of any of examples 33-35 wherein the first body region includes a first cavity of a heart of a patient and the second body region includes a second cavity of a heart of the patient, and wherein the first and second cavities of the heart of the patient include: (a) a left atrium and a right atrium, (b) a left ventricle and a right ventricle, or (c) a coronary sinus and the left ventricle.


CONCLUSION

Embodiments of the present disclosure may include some or all of the following components: a battery, supercapacitor, or other suitable power source; a microcontroller, FPGA, ASIC, or other programmable component or system capable of storing and executing software and/or firmware that drives operation of an implant; memory such as RAM or ROM to store data and/or software/firmware associated with an implant and/or its operation; wireless communication hardware such as an antenna system configured to transmit via Bluetooth, WiFi, or other protocols known in the art; energy harvesting means, for example a coil or antenna which is capable of receiving and/or reading an externally-provided signal which may be used to power the device, charge a battery, initiate a reading from a sensor, or for other purposes. Embodiments may also include one or more sensors, such as pressure sensors, impedance sensors, accelerometers, force/strain sensors, temperature sensors, flow sensors, optical sensors, cameras, microphones or other acoustic sensors, ultrasonic sensors, ECG or other cardiac rhythm sensors, SpO2 and other sensors adapted to measure tissue and/or blood gas levels, blood volume sensors, and other sensors known to those who are skilled in the art. Embodiments may include portions that are radiopaque and/or ultrasonically reflective to facilitate image-guided implantation or image guided procedures using techniques such as fluoroscopy, ultrasonography, or other imaging methods. Embodiments of the system may include specialized delivery catheters/systems that are adapted to deliver an implant and/or carry out a procedure. Systems may include components such as guidewires, sheaths, dilators, and multiple delivery catheters. Components may be exchanged via over-the-wire, rapid exchange, combination, or other approaches.


Embodiments of the present disclosure may be implemented as computer-executable instructions, such as routines executed by a general-purpose computer, a personal computer, a server, or other computing system. The present technology can also be embodied in a special purpose computer or data processor that is specifically programmed, configured, or constructed to perform one or more of the computer-executable instructions explained in detail herein. The terms “computer” and “computing device,” as used generally herein, refer to devices that have a processor and non-transitory memory, as well as any data processor or any device capable of communicating with a network. Data processors include programmable general-purpose or special-purpose microprocessors, programmable controllers, ASICs, programming logic devices (PLDs), or the like, or a combination of such devices. Computer-executable instructions may be stored in memory, such as RAM, ROM, flash memory, or the like, or a combination of such components. Computer-executable instructions may also be stored in one or more storage devices, such as magnetic or optical-based disks, flash memory devices, or any other type of non-volatile storage medium or non-transitory medium for data. Computer-executable instructions may include one or more program modules, which include routines, programs, objects, components, data structures, and so on that perform particular tasks or implement particular abstract data types.


The above detailed description of embodiments of the technology are not intended to be exhaustive or to limit the technology to the precise forms disclosed above. Although specific embodiments of, and examples for, the technology are described above for illustrative purposes, various equivalent modifications are possible within the scope of the technology as those skilled in the relevant art will recognize. For example, although steps are presented in a given order, alternative embodiments may perform steps in a different order. The various embodiments described herein may also be combined to provide further embodiments. For example, although this disclosure has been written to describe devices that are generally described as being used to create a path of fluid communication between the LA and RA, the LV and the right ventricle (RV), or the LA and the coronary sinus, it should be appreciated that similar embodiments could be utilized for shunts between other chambers of heart or for shunts in other regions of the body.


From the foregoing, it will be appreciated that specific embodiments of the technology have been described herein for purposes of illustration, but well-known structures and functions have not been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments of the technology. Where the context permits, singular or plural terms may also include the plural or singular term, respectively.


Unless the context clearly requires otherwise, throughout the description and the examples, the words “comprise,” “comprising,” and the like are to be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” As used herein, the terms “connected,” “coupled,” or any variant thereof, means any connection or coupling, either direct or indirect, between two or more elements; the coupling of connection between the elements can be physical, logical, or a combination thereof. Additionally, the words “herein,” “above,” “below,” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application. Where the context permits, words in the above Detailed Description using the singular or plural number may also include the plural or singular number respectively. As used herein, the phrase “and/or” as in “A and/or B” refers to A alone, B alone, and A and B. Additionally, the term “comprising” is used throughout to mean including at least the recited feature(s) such that any greater number of the same feature and/or additional types of other features are not precluded. It will also be appreciated that specific embodiments have been described herein for purposes of illustration, but that various modifications may be made without deviating from the technology. Further, while advantages associated with some embodiments of the technology have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the technology. Accordingly, the disclosure and associated technology can encompass other embodiments not expressly shown or described herein.

Claims
  • 1. A method for monitoring a shunting element implanted in a patient and having a lumen fluidly coupling a first body region of the patient and a second body region of the patient, wherein the lumen of the shunting element is selectively adjustable to control fluid flow therethrough, the method comprising: receiving a first radiographic image of at least two radiopaque elements associated with the lumen, wherein a spatial relationship between the at least two radiopaque elements varies according to a size of the lumen, and wherein the first radiographic image is taken from a first viewing angle;receiving a second radiographic image of the at least two radiopaque elements, wherein the second radiographic image is taken from a second viewing angle different than the first viewing angle; anddetermining the size of the lumen based, at least in part, on locations of the at least two radiopaque elements in the first and second radiographic images.
  • 2. The method of claim 1 wherein the second viewing angle is orthogonal to the first viewing angle.
  • 3. The method of claim 1 wherein the second viewing angle is orthonormal to the first viewing angle.
  • 4. The method of claim 1 wherein the at least two radiopaque elements are positioned at or near a perimeter of the lumen.
  • 5. The method of claim 4 wherein the at least two radiopaque elements include a first radiopaque element and a second radiopaque element positioned at diametrically opposite locations at or near the perimeter of the lumen.
  • 6. The method of claim 1 wherein the shunting element includes a structure at least partially surrounding the lumen, wherein the structure comprises one or more of a frame, a stent, a membrane, a ring, or a band, and wherein the structure includes the at least two radiopaque elements.
  • 7. The method of claim 1 wherein the at least two radiopaque elements comprise bands, markers, discs, rivets, fasteners, or beads.
  • 8. The method of claim 1 wherein the at least two radiopaque elements each have a spherical, cylindrical, or circular shape.
  • 9. The method of claim 1 wherein: the first and second radiographic images each include image data of at least one calibration element having a spherical, cylindrical, or circular shape; andthe method further comprises determining a scaling factor for the first and second radiographic images based at least in part on the image data of the at least one calibration element.
  • 10. The method of claim 9 wherein the at least one calibration element is carried by the shunting element.
  • 11. The method of claim 9 wherein the at least one calibration element is external to the patient's body.
  • 12. The method of claim 1 wherein the first viewing angle is an anterior-posterior viewing angle and the second viewing angle is a lateral viewing angle.
  • 13. The method of claim 1 wherein the first and second radiographic images are gated based on one or more of a respiratory cycle or a cardiac cycle of the patient.
  • 14. The method of claim 1 wherein determining the size of the lumen comprises: determining two-dimensional measurements of the at least two radiopaque elements in each of the first and second radiographic images; andcalculating a three-dimensional distance between the at least two radiopaque elements based on the two-dimensional measurements.
  • 15. The method of claim 1, further comprising adjusting the lumen of the shunting element before, during, and/or after obtaining the first and second radiographic images.
  • 16. The method of claim 1 wherein the first body region includes a first cavity of a heart of the patient and the second body region includes a second cavity of the heart of the patient, and wherein the first and second cavities of the heart of the patient include: (a) a left atrium and a right atrium, (b) a left ventricle and a right ventricle, or (c) a coronary sinus and the left ventricle.
  • 17. A system for monitoring a shunting element implanted in a patient and having a lumen fluidly coupling a first body region of the patient and a second body region of the patient, the system comprising: a processor; anda memory storing instructions that, when executed by the processor, cause the system to perform operations comprising: receiving first radiographic image data of at least two radiopaque elements associated with the lumen, wherein a spatial relationship between the at least two radiopaque elements varies according to a size of the lumen, wherein the lumen of the shunting element is selectively adjustable to control fluid flow therethrough, and wherein the first radiographic image data is taken from a first viewing angle;receiving second radiographic image data of the at least two radiopaque elements, wherein the second radiographic image data is taken from a second viewing angle different than the first viewing angle; anddetermining the size of the lumen based, at least in part, on locations of the at least two radiopaque elements in the first and second radiographic image data.
  • 18. The system of claim 17 wherein the second viewing angle is orthogonal to the first viewing angle.
  • 19. The system of claim 17 wherein the second viewing angle is orthonormal to the first viewing angle.
  • 20. A non-transitory computer-readable medium storing instructions that, when executed by a processor of a system for monitoring a shunting element implanted in a patient and having a lumen fluidly coupling a first body region of the patient and a second body region of the patient, cause the system to perform operations comprising: receiving first radiographic image data of at least two radiopaque elements associated with the lumen, wherein a spatial relationship between the at least two radiopaque elements varies according to a size of the lumen, wherein the lumen of the shunting element is selectively adjustable to control fluid flow therethrough, and wherein the first radiographic image data is taken from a first viewing angle;receiving second radiographic image data of the at least two radiopaque elements, wherein the second radiographic image data is taken from a second viewing angle different than the first viewing angle; anddetermining the size of the lumen based, at least in part, on locations of the at least two radiopaque elements in the first and second radiographic image data.
  • 21. The non-transitory computer-readable medium of claim 20 wherein the second viewing angle is orthogonal to the first viewing angle.
  • 22. The non-transitory computer-readable medium of claim 20 wherein the second viewing angle is orthonormal to the first viewing angle.
CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a 35 U.S.C. § 371 U.S. National Phase application of International Patent Application No. PCT/US2021/028787, filed Apr. 23, 2021, which claims the benefit of U.S. Provisional Patent Application No. 63/014,318, filed Apr. 23, 2020, each of which is herein incorporated by reference in its entirety.

PCT Information
Filing Document Filing Date Country Kind
PCT/US2021/028787 4/23/2021 WO
Publishing Document Publishing Date Country Kind
WO2021/216964 10/28/2021 WO A
US Referenced Citations (253)
Number Name Date Kind
3874388 King et al. Apr 1975 A
4601309 Chang Jul 1986 A
4662355 Pieronne et al. May 1987 A
4705507 Boyles Nov 1987 A
4836204 Landymore et al. Jun 1989 A
4979955 Smith Dec 1990 A
4995857 Arnold Feb 1991 A
5186431 Tamari Feb 1993 A
5267940 Moulder Dec 1993 A
5290227 Pasque Mar 1994 A
5312341 Turi May 1994 A
5326374 Ilbawi et al. Jul 1994 A
5332402 Teitelbaum Jul 1994 A
5334217 Das Aug 1994 A
5409019 Wilk Apr 1995 A
5429144 Wilk Jul 1995 A
5500015 Deac Mar 1996 A
5531759 Kensey et al. Jul 1996 A
5556386 Todd Sep 1996 A
5584803 Stevens et al. Dec 1996 A
5597377 Aldea Jan 1997 A
5645559 Hachtman et al. Jul 1997 A
5655548 Nelson et al. Aug 1997 A
5662711 Douglas Sep 1997 A
5702412 Popov et al. Dec 1997 A
5725552 Kotula et al. Mar 1998 A
5741297 Simon Apr 1998 A
5795307 Krueger Aug 1998 A
5810836 Hussein et al. Sep 1998 A
5824071 Nelson et al. Oct 1998 A
5916193 Stevens et al. Jun 1999 A
5941850 Shah et al. Aug 1999 A
5957949 Leonhardt et al. Sep 1999 A
6039759 Carpentier et al. Mar 2000 A
6077298 Tu et al. Jun 2000 A
6126686 Badylak et al. Oct 2000 A
6165188 Saadat et al. Dec 2000 A
6210318 Lederman Apr 2001 B1
6217541 Yu Apr 2001 B1
6242762 Brown et al. Jun 2001 B1
6254564 Wilk et al. Jul 2001 B1
6260552 Mortier et al. Jul 2001 B1
6270526 Cox Aug 2001 B1
6277078 Porat et al. Aug 2001 B1
6302892 Wilk Oct 2001 B1
6328699 Eigler et al. Dec 2001 B1
6344022 Jarvik Feb 2002 B1
6358277 Duran Mar 2002 B1
6406422 Landesberg Jun 2002 B1
6447539 Nelson et al. Sep 2002 B1
6451051 Drasler et al. Sep 2002 B2
6458153 Bailey et al. Oct 2002 B1
6468303 Amplatz et al. Oct 2002 B1
6478776 Rosenman et al. Nov 2002 B1
6491705 Gifford, III et al. Dec 2002 B2
6527698 Kung et al. Mar 2003 B1
6544208 Ethier et al. Apr 2003 B2
6562066 Martin May 2003 B1
6572652 Shaknovich Jun 2003 B2
6589198 Soltanpour et al. Jul 2003 B1
6632169 Korakianitis et al. Oct 2003 B2
6638303 Campbell Oct 2003 B1
6641610 Wolf et al. Nov 2003 B2
6652578 Bailey et al. Nov 2003 B2
6685664 Levin et al. Feb 2004 B2
6712836 Berg et al. Mar 2004 B1
6911043 Myers et al. Jun 2005 B2
7001409 Amplatz Feb 2006 B2
7011095 Wolf et al. Mar 2006 B2
7056294 Khairkhahan et al. Jun 2006 B2
7149587 Wardle et al. Dec 2006 B2
7175656 Khairkhahan Feb 2007 B2
7270675 Chun et al. Sep 2007 B2
7294115 Wilk Nov 2007 B1
7311690 Burnett Dec 2007 B2
7311730 Gabbay Dec 2007 B2
7317951 Schneider et al. Jan 2008 B2
7390310 McCusker et al. Jun 2008 B2
7513908 Lattouf Apr 2009 B2
7524329 Rucker Apr 2009 B2
7524330 Berreklouw Apr 2009 B2
7524332 Osborne et al. Apr 2009 B2
7608067 Bonni Oct 2009 B2
7699059 Fonseca et al. Apr 2010 B2
7736327 Wilk et al. Jun 2010 B2
7780725 Haug et al. Aug 2010 B2
7794473 Tessmer et al. Sep 2010 B2
7806921 Hoffman Oct 2010 B2
7892246 Akin et al. Feb 2011 B2
7905901 Corcoran et al. Mar 2011 B2
7922764 Gordy et al. Apr 2011 B2
7938840 Golden et al. May 2011 B2
7967769 Faul et al. Jun 2011 B2
7988724 Salahieh et al. Aug 2011 B2
8012198 Hill et al. Sep 2011 B2
8016877 Seguin et al. Sep 2011 B2
8043360 McNamara et al. Oct 2011 B2
8070708 Rottenberg et al. Dec 2011 B2
8091556 Keren et al. Jan 2012 B2
8096959 Stewart et al. Jan 2012 B2
8147545 Avior Apr 2012 B2
8157860 McNamara et al. Apr 2012 B2
8172896 McNamara et al. May 2012 B2
8235916 Whiting et al. Aug 2012 B2
8235933 Keren et al. Aug 2012 B2
8246677 Ryan Aug 2012 B2
8252042 McNamara et al. Aug 2012 B2
8303511 Eigler et al. Nov 2012 B2
8348996 Tuval et al. Jan 2013 B2
8398708 Meiri et al. Mar 2013 B2
8460366 Rowe Jun 2013 B2
8460372 McNamara et al. Jun 2013 B2
8597225 Kapadia Dec 2013 B2
8647381 Essinger et al. Feb 2014 B2
8696611 Nitzan et al. Apr 2014 B2
8740962 Finch et al. Jun 2014 B2
8745845 Finch et al. Jun 2014 B2
8747458 Tuval et al. Jun 2014 B2
8752258 Finch et al. Jun 2014 B2
8764848 Callaghan et al. Jul 2014 B2
8882697 Celermajer et al. Nov 2014 B2
8951223 McNamara et al. Feb 2015 B2
9005155 Sugimoto Apr 2015 B2
9034034 Nitzan et al. May 2015 B2
9138213 Amin et al. Sep 2015 B2
9205236 McNamara et al. Dec 2015 B2
9232997 Sugimoto et al. Jan 2016 B2
9277995 Celermajer et al. Mar 2016 B2
9358371 McNamara et al. Jun 2016 B2
9456812 Finch et al. Oct 2016 B2
9629715 Nitzan et al. Apr 2017 B2
9642993 McNamara et al. May 2017 B2
9649480 Sugimoto et al. May 2017 B2
9681948 Levi et al. Jun 2017 B2
9707382 Nitzan et al. Jul 2017 B2
9713696 Yacoby et al. Jul 2017 B2
9724499 Rottenberg et al. Aug 2017 B2
9757107 McNamara et al. Sep 2017 B2
9775636 Fazio et al. Oct 2017 B2
9918856 Favier et al. Mar 2018 B2
9937036 Sugimoto et al. Apr 2018 B2
9943670 Keren et al. Apr 2018 B2
9980815 Nitzan et al. May 2018 B2
10045766 McNamara et al. Aug 2018 B2
10076403 Eigler et al. Sep 2018 B1
10188375 McNamara et al. Jan 2019 B2
10207087 Keren Feb 2019 B2
10251740 Eigler et al. Apr 2019 B2
10292690 Celermajer et al. May 2019 B2
10350384 Farnan et al. Jul 2019 B2
10357357 Levi et al. Jul 2019 B2
10368981 Nitzan et al. Aug 2019 B2
10376359 Essinger et al. Aug 2019 B2
10376680 McNamara et al. Aug 2019 B2
10398421 Celermajer Sep 2019 B2
10405903 Biesinger et al. Sep 2019 B1
10413284 McNamara et al. Sep 2019 B2
10413286 McNamara et al. Sep 2019 B2
10463477 Forcucci et al. Nov 2019 B2
10463490 Rottenberg et al. Nov 2019 B2
10478594 Yacoby et al. Nov 2019 B2
10568751 McNamara Feb 2020 B2
10588611 Magnin et al. Mar 2020 B2
10610210 Finch et al. Apr 2020 B2
10624621 Celermajer Apr 2020 B2
10632292 Forcucci et al. Apr 2020 B2
10639459 Nitzan et al. May 2020 B2
10675450 Finch Jun 2020 B2
10828151 Nitzan et al. Nov 2020 B2
10835394 Nae et al. Nov 2020 B2
10898698 Eigler et al. Jan 2021 B1
10912645 Rottenberg et al. Feb 2021 B2
10925706 Eigler et al. Feb 2021 B2
10932786 McNamara et al. Mar 2021 B2
10940296 Keren Mar 2021 B2
10945716 Chen et al. Mar 2021 B2
11135410 Finch et al. Oct 2021 B2
11633194 Alexander et al. Apr 2023 B2
20020169371 Gilderdale Nov 2002 A1
20020169475 Gainor et al. Nov 2002 A1
20020177891 Miles et al. Nov 2002 A1
20030125798 Martin Jul 2003 A1
20030127090 Gifford et al. Jul 2003 A1
20040016514 Nien Jan 2004 A1
20040077988 Tweden et al. Apr 2004 A1
20040088045 Cox May 2004 A1
20040093075 Kuehne May 2004 A1
20040143294 Corcoran et al. Jul 2004 A1
20040147869 Wolf et al. Jul 2004 A1
20040162514 Alferness et al. Aug 2004 A1
20040210190 Kohler et al. Oct 2004 A1
20040215067 Stiger et al. Oct 2004 A1
20040215323 Stiger Oct 2004 A1
20050033351 Newton Feb 2005 A1
20050148925 Rottenberg et al. Jul 2005 A1
20050165344 Dobak, III Jul 2005 A1
20050192627 Whisenant et al. Sep 2005 A1
20060025857 Bergheim et al. Feb 2006 A1
20060111660 Wolf et al. May 2006 A1
20070010837 Tanaka Jan 2007 A1
20070010852 Blaeser et al. Jan 2007 A1
20070043435 Seguin et al. Feb 2007 A1
20070213813 Von Segesser et al. Sep 2007 A1
20070282157 Rottenberg et al. Dec 2007 A1
20080119891 Miles et al. May 2008 A1
20090243956 Keilman et al. Oct 2009 A1
20090276040 Rowe et al. Nov 2009 A1
20110054515 Bridgeman et al. Mar 2011 A1
20110218480 Rottenberg et al. Sep 2011 A1
20110218481 Rottenberg et al. Sep 2011 A1
20110257723 McNamara Oct 2011 A1
20110295183 Finch et al. Dec 2011 A1
20120290062 McNamara et al. Nov 2012 A1
20140128796 Keren et al. May 2014 A1
20140163449 Rottenberg et al. Jun 2014 A1
20140277054 McNamara et al. Sep 2014 A1
20150034217 Vad Feb 2015 A1
20150119796 Finch Apr 2015 A1
20150141807 Fetterly May 2015 A1
20150230843 Palmer et al. Aug 2015 A1
20160151179 Favier et al. Jun 2016 A1
20170340460 Rosen et al. Nov 2017 A1
20180014828 Fonte et al. Jan 2018 A1
20180256865 Finch et al. Sep 2018 A1
20190021861 Finch Jan 2019 A1
20190254814 Nitzan et al. Aug 2019 A1
20190262118 Eigler et al. Aug 2019 A1
20190269392 Celermajer et al. Sep 2019 A1
20190328513 Levi et al. Oct 2019 A1
20190336163 McNamara et al. Nov 2019 A1
20200060825 Rottenberg et al. Feb 2020 A1
20200078196 Rosen et al. Mar 2020 A1
20200078558 Yacoby et al. Mar 2020 A1
20200188143 McNamara Jun 2020 A1
20200245991 Celermajer Aug 2020 A1
20200261705 Nitzan et al. Aug 2020 A1
20200268515 Vettukattil et al. Aug 2020 A1
20200315599 Nae et al. Oct 2020 A1
20200368505 Nae et al. Nov 2020 A1
20210052378 Nitzan et al. Feb 2021 A1
20210059527 Najafi Mar 2021 A1
20210100665 Nae et al. Apr 2021 A1
20210121179 Ben-David et al. Apr 2021 A1
20210153776 Minar et al. May 2021 A1
20210177508 Kellerman Jun 2021 A1
20210259732 Dicicco et al. Aug 2021 A1
20210259829 Quinn Aug 2021 A1
20210259839 Cole et al. Aug 2021 A1
20210290214 Cole et al. Sep 2021 A1
20210299425 Kume et al. Sep 2021 A1
20210299430 Ratz et al. Sep 2021 A1
20210361257 Eimer et al. Nov 2021 A1
20240032869 Andriola et al. Feb 2024 A1
Foreign Referenced Citations (121)
Number Date Country
2005211243 Aug 2005 AU
2010344182 Aug 2012 AU
2011332324 Jun 2013 AU
2012214279 Aug 2013 AU
2018228451 Sep 2019 AU
2785041 Aug 2011 CA
2786575 Aug 2011 CA
2818417 May 2012 CA
2955389 Jan 2016 CA
3054891 Sep 2018 CA
101415452 Apr 2009 CN
102458316 May 2012 CN
102905626 Jan 2013 CN
103458832 Dec 2013 CN
105662653 Jun 2016 CN
109646063 Apr 2019 CN
110536657 Dec 2019 CN
2097012 Sep 2009 EP
2528646 Dec 2012 EP
2642954 Oct 2013 EP
2967867 Jan 2016 EP
3087953 Nov 2016 EP
3291773 Mar 2018 EP
3329860 Jun 2018 EP
3579907 Dec 2019 EP
3589238 Jan 2020 EP
3624701 Mar 2020 EP
2999412 May 2020 EP
3705154 Sep 2020 EP
3716877 Oct 2020 EP
3740163 Nov 2020 EP
3766431 Jan 2021 EP
3834737 Jun 2021 EP
3843618 Jul 2021 EP
3871626 Sep 2021 EP
3886761 Oct 2021 EP
3893731 Oct 2021 EP
3897369 Oct 2021 EP
176973 Dec 2006 IL
221127 Sep 2012 IL
226374 Jul 2013 IL
215975 Nov 2016 IL
227756 Jun 2017 IL
220201 Aug 2017 IL
253648 Sep 2017 IL
255379 Dec 2017 IL
252395 Apr 2020 IL
2011KN04472 Jul 2012 IN
2012KN01275 Feb 2013 IN
2013KN01954 Nov 2013 IN
2013CN06525 Aug 2014 IN
2012KN01988 Aug 2016 IN
2007527742 Oct 2007 JP
2010508093 Mar 2010 JP
2013046784 Mar 2013 JP
2014503246 Feb 2014 JP
2014512869 May 2014 JP
2020509812 Apr 2020 JP
20010046155 Jun 2001 KR
WO2005074367 Aug 2005 WO
WO2007083288 Jul 2007 WO
WO2008055301 May 2008 WO
WO2010128501 Nov 2010 WO
WO2010129089 Nov 2010 WO
WO2011093941 Aug 2011 WO
WO2011094521 Aug 2011 WO
WO2012071075 May 2012 WO
WO2012085913 Jun 2012 WO
WO2012109557 Aug 2012 WO
WO2013014539 Jan 2013 WO
WO2013096965 Jun 2013 WO
WO2014150106 Sep 2014 WO
WO2014188279 Nov 2014 WO
WO2016014821 Jan 2016 WO
WO2016038115 Mar 2016 WO
WO2016178171 Nov 2016 WO
WO2018158747 Sep 2018 WO
WO2019142152 Jul 2019 WO
WO2019179447 Sep 2019 WO
WO2019188917 Oct 2019 WO
WO2019189079 Oct 2019 WO
WO2019209420 Oct 2019 WO
WO2020094085 May 2020 WO
WO2020094087 May 2020 WO
WO2020094094 May 2020 WO
WO2020110048 Jun 2020 WO
WO2020123338 Jun 2020 WO
WO2020202046 Oct 2020 WO
WO2020215090 Oct 2020 WO
WO2020217194 Oct 2020 WO
WO2020219265 Oct 2020 WO
WO2020225698 Nov 2020 WO
WO2020225757 Nov 2020 WO
WO2020229636 Nov 2020 WO
WO2020234751 Nov 2020 WO
WO2020251700 Dec 2020 WO
WO2020259492 Dec 2020 WO
WO2021025905 Feb 2021 WO
WO2021026485 Feb 2021 WO
WO2021046753 Mar 2021 WO
WO2021055264 Mar 2021 WO
WO2021065873 Apr 2021 WO
WO2021065874 Apr 2021 WO
WO2021065875 Apr 2021 WO
WO2021065912 Apr 2021 WO
WO2021086707 May 2021 WO
WO2021091566 May 2021 WO
WO2021096766 May 2021 WO
WO2021101707 May 2021 WO
WO2021113670 Jun 2021 WO
WO2021136252 Jul 2021 WO
WO2021136261 Jul 2021 WO
WO2021138041 Jul 2021 WO
WO2021146342 Jul 2021 WO
WO2021158559 Aug 2021 WO
WO2021162888 Aug 2021 WO
WO2021178636 Sep 2021 WO
WO2021190547 Sep 2021 WO
WO2021212011 Oct 2021 WO
WO2021224736 Nov 2021 WO
WO2022093918 May 2022 WO
Non-Patent Literature Citations (30)
Entry
Jodi Perkins, “Corvia Medical and physIQ Partner in Global Phase 3 Heart Failure Clinical Trial to Leverage Novel Digital Endpoints,” Press Release, 2019 Copyright, Medical Alley Association, 3 pages.
Lehner et al., “The Creation of an Interatrial Right-To-Left Shunt in Patients with Severe, Irreversible Pulmonary Hypertension: Rationale, Devices, Outcomes,” Current Cardiology Reports (2019) 21: 31, https://doi.org/10.1007/s11886-019-1118-8; 9 pages.
International Search Report and Written Opinion received for International Application No. PCT/US21/28787, filed Apr. 23, 2021; Applicant: Shifamed Holdings, LLC; Date of Mailing: Aug. 10, 2021; 17 pages.
Extended European Search Report received for Application No. 21791938.0, Applicant: Shifamed Holdings, LLC; Date of Mailing: Apr. 3, 2024; 6 pages.
Ando et al., “Left ventricular decompression through a patent foramen ovale in a patient with hypertrophic cardiomyopathy: a case report,” Cardiovascular Ultrasound volume, Article No. 2 (2004).
Braunwald, Heart Disease, Chapter 6, 2015, p. 186.
Bridges et al., “The Society of Thoracic Surgeons practice guideline series: transmyocardial laser revascularization,” The Annals of Thoracic Surgery, vol. 77, Issue 4, Apr. 2004, pp. 1494-1502.
Bristow et al., “Improvement in cardiac myocyte function by biological effects of medical therapy: A new concept in the treatment of heart failure,” European Heart Journal, vol. 16, Issue suppl. F, Jul. 1995, pp. 20-31.
Case et al., “Relief of High Left-Atrial Pressure in Left-Ventricular Failure,” Lancet, Oct. 17, 1964, pp. 841-842.
Coats et al., “Controlled trial of physical training in chronic heart failure. Exercise performance, hemodynamics, ventilation, and autonomic function,” Circulation, 1992;85:2119-2131.
Davies et al., “Reduced contraction and altered frequency response of isolated ventricular myocytes from patients with heart failure,” Circulation, (1995), 92:2540-2549, Circulation, (1995), 92:2540-2549.
Ennezat et al., “An unusual case of low-flow, low gradient severe aortic stenosis: Left-to-right shunt due to atrial septal defect,” Cardiology, (2009), 113(2):146-148.
Ewert et al., “Masked Left Ventricular Restriction in Elderly Patients With Atrial Septal Defects: A Contraindication for Closure,” Catheterization and Cardiovascular Interventions, 52: 177-180, 2001.
Ewert et al., “Acute left heart failure after interventional occlusion of an atrial septal defect,” Z. Kardiol., Catheterization and Cardiovascular Interventions, Z. Kardiol., (May 2001), 90(5):362-366.
Geiran et al., “Changes in cardiac dynamics by opening an interventricular shunt in dogs,” J. Surg. Res., (Jan. 1990), 48(1):6-12.
Gelernter-Yaniv et al., “Transcatheter closure of left-to-right interatrial shunts to resolve hypoxemia,” Congenit. Heart Dis., (Jan. 2008), 31(1):47-53.
Gewillig et al., “Creation with a stent of an unrestrictive lasting atrial communication,” Cardio. Young, (2002), 12(4):404-407.
Khositseth et al., “Transcatheter Amplatzer Device Closure of Atrial Septal Defect and Patent Foramen Ovale in Patients With Presumed Paradoxical Embolism,” Mayo Clinic Proc., 79:35-41 (2004).
Kramer et al., “Controlled study of captopril in chronic heart failure: A rest and exercise hemodynamic study,” Circulation, (1983), 67(4):807-816.
Lai et al., “Bidirectional shunt through a residual atrial septal defect after percutaneous transvenous mitral commissurotomy,” Cardiology, (1993), 83(3):205-207.
Lemmer et al., “Surgical implications of atrial septal defect complicating aortic balloon valvuloplasty,” Ann. thorac. Surg., (Aug. 1989), 48(2):295-297.
Park et al., “Blade atrial septostomy: collaborative study,” Circulation, 66(2):258-266 (1982).
Roven et al., “Effect of Compromising Right Ventricular Function in Left Ventricular Failure by Means of Interatrial and Other Shunts,” American Journal Cardiology, 24:209-219 (1969).
Salehian et al., “Improvements in Cardiac Form and Function After Transcatheter Closure of Secundum Atrial Septal Defects,” Journal of the American College of Cardiology, 45(4):499-504 (2005).
Schmitto et al., “Chronic heart failure induced by multiple sequential coronary microembolization in sheep,” The International Journal of Artificial Organs, 31(4):348-353 (2008).
Schubert et al., “Left ventricular conditioning in the elderly patient to prevent congestive heart failure after transcatheter closure of the atrial septal defect,” Catheter Cardiovasc. Interv., (2005), 64(3):333-337.
Stormer et al., “Comparative study of in vitro flow characteristics between a human aortic valve and a designed aortic and six corresponding types of prosthetic heart valves,” European Surgical Research, (1976), 8(2):117-131.
Stumper et al., “Modified technique of stent fenestration of the atrial septum, Heart,” (2003), 89:1227-1230.
Trainor et al., “Comparative Pathology of an Implantable Left Atrial Pressure Sensor.” ASAIO Journal, Clinical Cardiovascular/Cardiopulmonary Bypass, 59(5):486-92 (2013).
Zhou et al., “Unidirectional valve patch for repair of cardiac septal defects with pulmonary hypertension,” Annals of Thoracic Surgeons, 60: 1245-1249, 1995.
Related Publications (1)
Number Date Country
20240000404 A1 Jan 2024 US
Provisional Applications (1)
Number Date Country
63014318 Apr 2020 US