Patent Publication Number: US-2023136820-A1

Title: MULTl-MATERIAL THREE-DIMENSIONAL PRINTED PORTION OF A HEART

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit and priority to U.S. Provisional Application Number 62/955,133, filed on Dec. 30, 2019, the entirety of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     This disclosure is directed to simulation devices, and more particularly, to a multi-material three-dimensional printed portion of a heart for cardiovascular simulation devices. 
     BACKGROUND 
     Heart disease is the leading cause of mortality and morbidity in the modern world. Numerous mini-invasive therapies such as percutaneous or transcatheter interventions have recently been introduced for treatment of structural heart disease (SHD). However, currently, there are limited opportunities and tools for SHD teams to plan and practice any structural heart intervention in the cardiac catheterization laboratory environment. 
     SUMMARY 
     Example 1 Disclosed is a multi-material three-dimensional printed portion of the heart configured to mimic an anatomical shape and a mechanical behavior of the portion of the heart, comprising: a frame made from acrylonitrile butadiene styrene (ABS) having a Young’s modulus of between 1 and 2 GPA; a first layer including a plurality of polygons, each said polygon having a plurality of vertices composed of a first material, each said polygon defining an interior portion filled with a second material different that the first material; and second and third layers sandwiching the first layer, the second and third layers composed of a third material; wherein the first material is a photopolymerized Acrylate-Based PEG Hydrogels; wherein the second and third materials each have a second Young’s modulus of between 0.3 and 7 MPa. 
     Example 2 The multi-material three-dimensional printed portion of the heart of Example 1, wherein each of the plurality of polygons have a diameter d determined as a largest distance between any pair of the plurality of vertices for a given polygon, where d is between 5.0 mm to 6.0 millimeters. 
     Example 3 The multi-material three-dimensional printed portion of the heart of Example 1, wherein each of the vertices of the plurality of polygons have a thickness d, where d is between 0.4 and 0.5 millimeters 
     Example 4 The multi-material three-dimensional printed portion of the heart of Example 1, wherein the first material is a photopolymerized Acrylate-Based PEG Hydrogels. 
     Example 5 The multi-material three-dimensional printed portion of the heart of Example 1, wherein the second and third material are Acrylate photopolymerized resin, like Polyjet® materials of Young’s modulus comprised between 0.3 to 7 MPa. 
     Example 6 The multi-material three-dimensional printed portion of the heart of Example 1, wherein the first layer has a thickness D 1 , where D 1  is between 0.3 and 0.4 millimeters. 
     Example 7 The multi-material three-dimensional printed portion of the heart of Example 1, wherein the second and third layers each has a thickness D 2 , where D 2  is between 0.3 and 0.35 millimeters. 
     Example 8 The multi-material three-dimensional printed portion of the heart of Example 1, wherein first, second and third materials are radiofrequency compatible materials. 
     Example 9 The multi-material three-dimensional printed portion of the heart of Example 1, having a superior-inferior diameter of, 20.8±6.2 mm. 
     Example 10 The multi-material three-dimensional printed portion of the heart of Example 1, having an anterior-posterior diameter of, 15.7±6.2 mm. 
     Example 11 The multi-material three-dimensional printed portion of the heart of Example 1, having a thickness equal to, 0.68±0.27 mm. 
     Example 12 A multi-material three-dimensional printed portion of the heart configured to mimic an anatomical shape and a mechanical behavior of the portion of the heart, comprising: a first layer including a plurality of coaxial, closed geometric shapes, each said closed geometric shape composed of a first material, each said closed geometric shape defining an interior portion filled with a second material different that the first material; second and third layers sandwiching the first layer, the second and third layers composed of a third material; wherein the first material is a photopolymerized Acrylate-Based PEG Hydrogels wherein the second and third materials each have a second Young’s modulus of between 0.3 and 7 MPa. 
     Example 13 The multi-material three-dimensional printed portion of the heart of Example 12, wherein the first material is elastic Acrylate photopolymerized resin. 
     Example 14 The multi-material three-dimensional printed portion of the heart of Example 12, wherein the second material is 1%-40% elastic Acrylate photopolymerized resin by weight with the balance formed of Hydrogel. 
     Example 15 The multi-material three-dimensional printed portion of the heart of Example 12, wherein the third material is 1%-40% elastic Acrylate photopolymerized resin by weight with the balance formed of Hydrogel. 
     Example 16 The multi-material three-dimensional printed portion of the heart of Example 12, wherein three-dimensional printed portion of the heart is a fossa ovalis; wherein the plurality of closed geometric shapes are each generally circular fibers and comprise a first closed geometric shape having a radius r-1, a second closed geometric shape having a radius r-2, and a third closed geometric shape having a radius r-3, where radius r-1 is 20% of a radius Rfo of the fossa ovalis, radius r-2 is 50% of the radius Rfo of the fossa ovalis, and radius r-3 is 80% of the radius Rfo of the fossa ovalis. 
     Example 17 The multi-material three-dimensional printed portion of the heart of Examples 12-16, wherein each of the plurality of closed geometric shapes have a width w, where w is between 0.5 and 0.8 millimeters. 
     Example 18 The multi-material three-dimensional printed portion of the heart of Examples 12-17, wherein the first layer has a thickness D 1 , where D 1  is between 0.2 and 0.4 millimeters. 
     Example 19 The multi-material three-dimensional printed portion of the heart of Examples 12-18, wherein the second and third layers each has a thickness D 2 , where D 2  is between 0.3 and 0.35 millimeters. 
     Example 20 The multi-material three-dimensional printed portion of the heart of Examples 12-19, wherein first, second and third materials are radiofrequency compatible materials. 
     It is understood that various configurations of the subject technology will become readily apparent to those skilled in the art from the disclosure, wherein various configurations of the subject technology are shown and described by way of illustration. As will be realized, the subject technology is capable of other and different configurations and its several details are capable of modification in various other respects, all without departing from the scope of the subject technology. Accordingly, the summary, drawings and detailed description are to be regarded as illustrative in nature and not as restrictive. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and related objects, features, and advantages of the present disclosure will be more fully understood by reference to the following detailed description, when taken in conjunction with the following figures, wherein: 
         FIG.  1    illustrates various interventional cardiac procedures that can be simulated with a physical simulator device according to aspects of the disclosure. 
         FIG.  2    illustrates an exemplary catheterization (Cath) lab including a physical simulator device, according to aspects of the disclosure. 
         FIG.  3    illustrates a physical simulator device in partial transparency and overlaid on a patient, according to aspects of the disclosure. 
         FIG.  4    illustrates various locations on a septum of a heart for a transseptal puncture for various procedures. 
         FIGS.  5 A and  5 B  illustrate further details of a physical simulator device, according to aspects of the disclosure. 
         FIG.  6    illustrates a perspective view of a physical simulator device, according to aspects of the disclosure. 
         FIG.  7    illustrates a cross-sectional side view of a station of a physical simulator device, according to aspects of the disclosure. 
         FIG.  8    illustrates a side view, in partial transparency and aligned with a patient, of a station of a physical simulator device, according to aspects of the disclosure. 
         FIG.  9    illustrates a cross-sectional side view of an esophageal access system of a physical simulator device, according to aspects of the disclosure. 
         FIG.  10    illustrates a cross-sectional side view of the station of a physical simulator device, according to aspects of the disclosure. 
         FIG.  11    illustrates a side view, in partial transparency of a physical simulator device including a patient-specific cartridge, according to aspects of the disclosure. 
         FIG.  12    illustrates a cross-sectional end view of a lumen of a physical simulator device, according to aspects of the disclosure. 
         FIG.  13    illustrates a perspective view of a portion of an esophageal access system of a physical simulator device, according to aspects of the disclosure. 
         FIG.  14    illustrates a top view of a portion of a physical simulator device, according to aspects of the disclosure. 
         FIGS.  15 A and  15 B  illustrate exploded perspective and perspective views of a vascular access device of a physical simulator device, according to aspects of the disclosure. 
         FIGS.  16 A and  16 B  illustrate side and top views of the vascular access device of a physical simulator device, according to aspects of the disclosure. 
         FIG.  17    illustrates a cross-sectional top view of a physical simulator device, according to aspects of the disclosure. 
         FIG.  18    illustrates a perspective view of an access port of a station of a physical simulator device, according to aspects of the disclosure. 
         FIG.  19    illustrates through holes of the access port of  FIG.  18   , according to aspects of the disclosure. 
         FIG.  20    illustrates a perspective view of a housing of a station of a physical simulator device, according to aspects of the disclosure. 
         FIG.  21    illustrates another perspective view of the housing of the station of a physical simulator device, according to aspects of the disclosure. 
         FIG.  22    illustrates an acoustic coating for a tank of station of a physical simulator device, according to aspects of the disclosure. 
         FIG.  23    illustrates ultrasound images obtained with and without an acoustic coating in a tank of a physical simulator device, according to aspects of the disclosure. 
         FIG.  24    illustrates a cross-sectional side view of a tank of station of a physical simulator device, according to aspects of the disclosure. 
         FIG.  25    illustrates a perspective view of a patient-specific cartridge of a physical simulator device, according to aspects of the disclosure. 
         FIGS.  26 A and  16 B  illustrate perspective and top views of another patient-specific cartridge of a physical simulator device, according to aspects of the disclosure. 
         FIGS.  27 - 1 A -  27 - 1 H  illustrate features of a fossa ovalis of a patient-specific model of a patient-specific cartridge of a physical simulator device, according to aspects of the disclosure. 
         FIGS.  27 - 2 A -  27 - 2 E shows an example cardiac model cartridge  308  with the removable septum cartridge  308 ′ removed/installed. 
         FIG.  27 – 27 F  is a graph illustrating the difference in mechanical properties between the honeycomb structure of  FIG.  27 - 1 B and the concentric closed-shape structure of  FIG.  27.1 D ). 
         FIG.  28    illustrates ultrasound images of a patient-specific model in a tank of a physical simulator device, that may be obtained using an ultrasound device disposed in the tank of the physical simulator device, according to aspects of the disclosure. 
         FIG.  29    illustrates a left atrial appendage of a patient-specific model of a patient-specific cartridge of a physical simulator device, according to aspects of the disclosure. 
         FIG.  30    illustrates a portion of a patient heart that can be modeled by a patient-specific model of a patient-specific cartridge of a physical simulator device, according to aspects of the disclosure. 
         FIG.  31    illustrates a perspective view of a patient-specific cartridge having a standard frame, according to aspects of the disclosure. 
         FIG.  32    illustrates a perspective view of a standard frame for a patient-specific cartridge, according to aspects of the disclosure. 
         FIG.  33    illustrates a perspective view of a patient-specific cartridge having a patient-specific model coupled to a standard frame, according to aspects of the disclosure. 
         FIG.  34    illustrates another perspective view of a patient-specific cartridge having another patient-specific model coupled to a standard frame, according to aspects of the disclosure. 
         FIG.  35    illustrates a patient-specific model, according to aspects of the disclosure. 
         FIG.  36    illustrates another perspective view of a standard frame of a patient-specific cartridge coupled to various different patient-specific models, according to aspects of the disclosure. 
         FIG.  37    illustrates a coupling portion of a patient-specific model for coupling to a standard frame, according to aspects of the disclosure. 
         FIGS.  38 A and  38 B  respectively illustrate misaligned patient portions and corresponding coupling portions of a patient-specific model for coupling to a standard frame, according to aspects of the disclosure. 
         FIG.  39    illustrates another example of misaligned patient portions and corresponding coupling portions of a patient-specific model for coupling to a standard frame, according to aspects of the disclosure. 
         FIG.  40    illustrates various aspects of a process for manufacturing a patient-specific cardiac model for coupling to a standard frame, according to aspects of the disclosure. 
         FIG.  41    illustrates a fluoroscopic image of a surgical instrument in a portion of a patient’s heart, according to aspects of the disclosure. 
         FIG.  42    illustrates a fluoroscopic image of a surgical instrument in a patient-specific model of a patient’s heart, according to aspects of the disclosure. 
         FIG.  43    illustrates a cross-sectional view of a portion of a wall of a patient-specific model of a patient’s heart, according to aspects of the disclosure. 
         FIG.  44    illustrates a cross-sectional view of a portion of a coated wall of a patient-specific model of a patient’s heart, according to aspects of the disclosure. 
         FIG.  45    illustrates a process for injecting a light-reactive material into a wall of a patient-specific model of a patient’s heart, according to aspects of the disclosure. 
         FIG.  46    illustrates a perspective view of a spinal shadow card, according to aspects of the disclosure. 
         FIG.  47    illustrates a side view of a station of a physical simulator device with a spinal shadow card, according to aspects of the disclosure. 
         FIG.  48    illustrates a schematic view of a fluid flow system of a physical simulator device, according to aspects of the disclosure. 
         FIG.  49    illustrates a schematic view of another fluid flow system of a physical simulator device, according to aspects of the disclosure. 
         FIG.  50    illustrates a schematic view of a fluid heating system of a physical simulator device, according to aspects of the disclosure. 
         FIG.  51    illustrates a perspective view of an accessory fluid heater for a physical simulator device, according to aspects of the disclosure. 
         FIG.  52    illustrates a cross-sectional view of a mounting member of an accessory fluid heater for a physical simulator device, according to aspects of the disclosure. 
         FIG.  53 A  illustrates a perspective view of another accessory fluid heater for a physical simulator device, according to aspects of the disclosure. 
         FIG.  53 B  illustrates a cross-sectional view of a mounting portion of the accessory fluid heater of  FIG.  53 A , according to aspects of the disclosure. 
         FIG.  53 C  illustrates a cross-sectional view of a mounting portion and a heating element of the accessory fluid heater of  FIG.  53 A , according to aspects of the disclosure. 
         FIG.  54    illustrates a perspective view of a flush system for a physical simulator device, according to aspects of the disclosure. 
         FIGS.  55  and  56    illustrate schematic views of respective open and closed arrangements of a portion of a fluid flow system of a physical simulator device for coupling to the flush system of  FIG.  54   , according to aspects of the disclosure. 
         FIG.  57    illustrates a cross-sectional view of a Y-pipe of a fluid flow system of a physical simulator device for coupling to the flush system of  FIG.  54   , according to aspects of the disclosure. 
         FIG.  58    illustrates a schematic side view of a patient-specific cartridge during installation in a tank of a station of a physical simulator device, according to aspects of the disclosure. 
         FIG.  59    illustrates a schematic side view of a patient-specific cartridge installed in a tank of a station of a physical simulator device, according to aspects of the disclosure. 
         FIG.  60    illustrates a schematic perspective view of securement members on a frame of a patient-specific cartridge, according to aspects of the disclosure. 
         FIG.  61    illustrates a schematic perspective view of securement members on a sidewall of a tank of station, according to aspects of the disclosure. 
         FIG.  62    illustrates a schematic side view of a securement interaction between securement members on a sidewall of a tank of station and corresponding securement members of a frame of a patient-specific cartridge, according to aspects of the disclosure. 
         FIG.  63    illustrates a schematic side view of a securement interaction between an access port of a tank of station and a front support of a frame of a patient-specific cartridge, according to aspects of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, numerous specific details are set forth to provide a full understanding of the present disclosure. It will be apparent, however, to one ordinarily skilled in the art that embodiments of the present disclosure may be practiced without some of the specific details. In other instances, well-known structures and techniques have not been shown in detail so as not to obscure the disclosure. 
     Interventional cardiologists work with fluoroscopy as the main tool for real-time guidance of catheter-based therapy. Since interventions in structural heart disease (SHD) are performed on the beating heart, visualization of the relevant structures with means other than direct visual inspection by the surgeon is crucial. Advances in cardiac imaging with three-dimensional transesophageal echocardiography (TEE) have proven particularly helpful in demonstrating the complex cardiac morphology and in performing necessary pre-interventional precise measurements for planning and tailoring of percutaneous therapies. 
     Virtual and physical simulators offer the opportunity to train for a procedure before actions can influence patient out-comes, insulating patients from risk during the novice operator period. The use of simulators also reduces training time and facilitates more structured, comprehensive skill acquisition when compared to the classical apprenticeship model. However, existing simulation devices for training and/or planning do not reproduce a realistic biomechanical behavior and/or are not visible on ultrasound imaging with visual aspects close to those of biological tissues. 
     Therefore, a need exists for a physical simulator device that can assist in training and planning for structural heart disease interventions, which can replicate the interaction (e.g., friction, feedback force, etc.) between the cardiovascular wall and the surgical tools in a mechanically accurate manner, and in a manner that is visible on ultrasound imaging with visual aspects close to those biological tissues. 
     In the last several years, there has been an explosion in Structural Heart Diseases (SHD) interest, driven largely by the adoption of transcatheter aortic valve replacement, mitral valve interventions, and transcatheter left atrial appendage closure. 
     Structural heart interventions are performed with specially designed catheters, guides, sheaths, and implantation tools. For example,  FIG.  1    shows part of a  2016  Mayo Clinic® graphic which illustrates eight structural heart interventions (labeled A-H) that are performed, in part, by inserting one or more of the specially designed catheters, guides, sheaths, and implantation tools from the inferior vena cava  110  into the right atrium  101  of a heart  100  of a patient, then into the left atrium  102  via a transseptal puncture through the septum  112 . As shown in  FIG.  1   , these interventions can be performed to manipulate and/or address issues with the mitral valve between the left atrium  102  and the left ventricle  104 , the pulmonary vein  114 , and/or the left atrial appendage  116  (as examples). 
     To perform successful interventions (e.g., of the types shown in  FIG.  1   ) without causing any harm, it is mandatory to use these tools with high precision. For example, the transseptal puncture may be formed at different locations on the septum  112  for different procedures. For this and other reasons, SHD interventions are complex, and numerous guidelines recommend the implementation of a multidisciplinary SHD team rather than a single person. The SHD team typically consists of cardiologists and cardiac interventionalists, a cardiac surgeon, cardiovascular imaging specialists, anesthesiologists, and specialized nurses. The action of the intervening specialists heavily depends on images offered by the imaging specialist, who in turn needs to know the structures relevant to the interventionalist and what views are optimal for guiding the procedure. Identifying structures simultaneously on echocardiographic and fluoroscopic imaging is complicated and prone to miscommunication. 
     The systems and methods disclosed herein provide a training and planning tool for SHD procedures, such as those illustrated in  FIG.  1   , that better aids training and pre-operative planning for interventional cardiology procedures. For example, a physical simulation device is disclosed which accurately replicates a specific patient’s anatomy and cardiac wall mechanical behavior, and, when imaged using ultrasound imaging, generates images with visual aspects that are close to the corresponding visual aspects of the corresponding biological tissues of the patient under ultrasound imaging. As will be described in further detail hereinafter, the physical simulator device can include a station that includes a housing having a tank within which a patient-specific cardiac model can be disposed, an esophageal access system within the housing, and a vascular access system coupled to the housing. A patient-specific cartridge can be placed into the tank, the cartridge including a standard frame and a multi-material patient-specific cardiac model with realistic biomechanical properties and that is visible on ultrasound imaging with aspect close to biological tissues. The simulator system (e.g., including the station and the cartridge) can be arranged to mimic the characteristics (e.g., the geometry, acoustic impedance and biomechanics) of the human right and left atrium, and to fit the environment of a non-sterile operating room (e.g., a Cath lab) without the presence of any patient. 
     For example,  FIG.  2    illustrates a Cath lab  200  implementing a simulator system that includes a physical simulator device  202  (e.g., supported on a Cath lab table  210 ), an imaging system  204  (e.g., an ultrasound imaging system), a control station  208  for the imaging system, and a display  206  on which images such as ultrasound images of a cartridge within a tank of the station of the physical simulator device  202  can be seen. 
     Details of the physical simulator device  202  are shown in  FIG.  3   . In  FIG.  3   , physical simulator device  202  is shown in partial transparency over a depiction  399  of a human body so that the alignment between various features of the physical simulator device  202  and body of a patient can be seen. In particular,  FIG.  3    shows show the physical simulator device  202  may include a station  300  having a tank  306  arranged to receive a patient-specific cartridge  308  that mimics the mechanical and acoustic features of at least portions of a heart of a particular patient. 
     As shown, the tank  306  is positioned relative to an esophageal access port  304  and vascular access port  310 , in accordance with the relative positions of the patient’s heart relative to the patient’s mouth and a femoral vein puncture location. In this way, the arrangement of the physical simulator device  202  mimics the relative locations of the organ to be operated on (e.g., the heart), an ultrasound access point (e.g., the patient’s mouth), and a vascular access port (e.g., along the femoral vein). For example,  FIG.  3    also shows how the physical simulator device  202  includes a vascular access system  302  coupled to the station  300 , and having a curvature that allows the vascular access system  302  to mimic a portion of the femoral vein, the right external and common iliac veins  312 , and the vena cava  314  leading to the right atrium of the simulated patient heart in cartridge  308 . 
     In some implementations, the combination of the cartridge  308  and the station  300  aim to achieve the functionality of all the anatomical parts needed for a Left Atrial Appendage (LAA) closure intervention. The station  300  and a frame of the cartridge  308  may represent standard anatomical parts (e.g., of a generic patient) and a patient-specific model of the cartridge  308  may represent the patient-specific anatomical parts. 
     In this example, the LAA closure intervention starts with a puncture at a port  310  in the femoral vein replica (e.g., a standard-patient part), and then a guidewire is installed through the replica to the right atrium replica of the heart simulated by cartridge  308 . The catheter enters the cartridge  308 , which includes the patient-specific part of the system. 
     To access to the LAA, the cardiologist must cross the replicate septum of the cartridge  308  at a specific spot for the LAA procedure, within the fossa ovalis. For example,  FIG.  4    is a portion of a Mayo Clinic® image that illustrates a location  408  on the fossa ovalis  400  for the transseptal puncture for a LAA procedure. Other locations on the fossa ovalis  400  are also shows for transseptal punctures for other procedures, such as a location  404  for a transseptal patent foramen ovale closure, a location  402  for a paravalvular leak closer, a location  406  for a percutaneous left ventricular assist device placement, and a location  410  for a pulmonary vein intervention. 
     Cartridge  308  includes a patient-specific model, in which the position and the shape of the fossa ovalis is patient specific. The mechanical features of the patient-specific model, such as the mechanical response of the modeled fossa ovalis to external forces (e.g., forces exerted by surgical instruments) may be patient-specific to mimic the mechanical response of the corresponding tissue of the patient’s heart, responsive to the same forces. The thickness and/or material properties of portions of the model (e.g., the fossa ovalis) can be arranged to generate the desired patient-specific mechanical features, as described in further detail hereinafter. In the LAA example, once the catheter is in the left atrium, the cardiologist pushes the guidewire inside the patient-specific upper pulmonary vein replica of the cartridge  308 . Then the surgeon pulls on the catheter, crosses the ridge between the replicated pulmonary vein and ends in the LAA, and deploys the device. 
     As shown in  FIG.  3   , during a simulated procedure, the cartridge  308  is positioned within the tank  306  disposed within the station  300 , and submerged in a blood mimicking fluid  307  in the tank  306 , so that the simulated tissue and interventional tools can be seen under ultrasound imaging (as described in further detail hereinafter). Station  300  may also include fluid control systems for circulating, flushing, filtering, heating, and/or otherwise manipulating the blood mimicking fluid  307 , as described in further detail hereinafter. 
       FIGS.  5 A and  5 B  show additional views of the physical simulator device  202  during a simulated LAA procedure, with portions of the physical simulator device  202  shown in partial transparency for clarity of other features. For example, in  FIG.  5 A , the cartridge  308 , the housing  309  of station  300 , and the housing of vascular access system  302  are shown in partial transparency so that an ultrasound probe  505  (e.g., a transesophageal echocardiographic (TEE) ultrasound probe), a guidewire  507 , and operational components  501  (e.g., pumps for moving fluid through the physical simulator device  202 ) can be seen. In this example, the ultrasound device  505  has been inserted, via an esophageal access system within the station, under the cartridge  308  in the tank  306 . Guidewire  507  has been inserted via vascular access device  302 , through into a portion of the patient-specific cartridge  308 . 
       FIG.  5 B  shows station  300  in partial transparency so that cartridge  308  can be seen with a delivery device for an LAA closure device  502  having been passed through a transseptal puncture  511  in a simulated septum  112 ′ to close the simulated LAA  116 ′. A position marker  500  on the delivery device can also be seen. 
       FIG.  6    illustrates a perspective view of the physical simulator device  202 , according to aspects of the disclosure. In the example of  FIG.  6   , housing  309  of station  300  can be seen coupled to a surgical access device such as vascular access system  302 . In this example, the vascular access port  310  at the proximal end of the vascular access system  302  can be seen. Tank  306  in the housing  309  of station  300  can also be seen. 
     The station  300  and/or vascular access system  302  may be arranged to represent certain standard (i.e., non-patient specific) anatomical parts involved in a simulated intervention. The primary functions of the station  300  are to hold the cartridge  308  (e.g., including the patient-specific cardiac model) in an anatomically relevant position, circulate fluid through the cartridge  308  to simulate blood flow, and provide anatomically realistic vascular and esophageal access. 
     The simulated vascular access provided by vascular access system  302  simulates the right femoral vein, iliac vein, and inferior vena cava access. The simulated esophageal access can be disposed within housing  309  and provides a path for insertion and placement of, for example, a transesophageal echocardiographic (TEE) ultrasound probe for imaging the simulated procedure. A pump (e.g., implemented as one of components  501  of  FIG.  5   ) simulates blood flow through the heart to enable realistic dispersion of contrast agents introduced through the catheter employed during the practiced procedure, and to replicate the fluid mechanical forces to be experienced by the surgeon during the procedure. The pump can also purge the station  300  of fluid post procedure. 
     The station  300  and vascular access device  302  are designed to be positionable on a Cath Lab patient bed with all components being positioned in corresponding anatomical positions of a patient on the bed, as depicted in  FIG.  3   . Accordingly, and as described in further detail hereinafter, the station  300  includes a main housing  309  surrounding the pump (e.g., pump  501 ), the tank  306  (in which the cartridge can be positioned), an imaging access system such as a replicated esophageal access system (also referred to herein as a TEE approach system), and a catheterization path channel. 
     Although various examples disclosed herein are described in connection with a simulator device for cardiac procedures, it should be appreciated that a physical simulator device for simulating procedures for other organs of bodily features can also be provided with station, a tank, a patient-specific cartridge corresponding to the organ, a surgical access device for simulating interventional access to the organ, and an imaging access device for simulating imaging component access to the organ, without departing from the scope of the disclosure. For example, the physical simulator device  202  may be implemented with as a surgical simulation device that includes a patient-specific cartridge  308  that replicates anatomical and acoustic features of an organ (e.g., a heart, a lung, a stomach, a urinary bladder, a bone, a lymph node, a larynx, a pharynx, muscle vasculature, a spinal column, an intestine, a colon, a rectum, or an eye) of a specific patient, a station  300  including a tank  306  configured to receive the patient-specific cartridge  308 , a surgical access system  302  coupled to the station  300  and including a lumen  1700  extending from a surgical access port  310  to an access port  718  for the tank  306 , the lumen  1700  configured to simulate a blood vessel of a generic patient, and an imaging access system  700  extending within the station  300  from an imaging access port  304  to the tank  306 , the imaging access system comprising a lumen  900  configured to simulate an imaging access pathway within the generic patient. 
       FIG.  7    illustrates a cross-sectional side view of a station  300  with an imaging access system implemented as an esophageal access system  700 . In the example of  FIG.  7   , esophageal access system  700  extends, within housing  309 , from a proximal end  710  at the imaging access port  304  on housing  309  to a distal end  714  within the housing. As shown, the distal end  714  forms a port in the tank  306  that allows an imaging device, such as a TEE device, to be extended into the tank from imaging access port  304 . A proximal membrane  711  at imaging access port  304 , and distal membrane  712  at an interface between a first pipe member  702  and a second pipe member  704  of the esophageal access system  700  may be included.  FIG.  7    also shows how the housing  309  of station  300  may include an access port  706  to which vascular access system  302  can be attached, and which includes an additional port  718  into tank  306 , opposite to the port formed at the distal end  714  of the esophageal access system  700 . Port  718  may be arranged to interface with a superior vena cava (SVC) interface on the patient-specific cartridge  308 , as described in further detail hereinafter. 
     For ergonomic and sealing reasons, the replicated esophageal access system/TEE approach system  700  may not be fully anatomical in terms of shape, size and angulation of a patient’s esophagus  708 . Instead, a standardized approach for the TEE approach system  700  may be used that allows a clinician to place a TEE probe  505  in a position in the station  300  that corresponds to the position a TEE probe would be positioned during an actual procedure, with similar, though not fully simulated tactile feedback provided to the clinician. 
     For example,  FIG.  8    illustrates station  300  in partial transparency, in side-view alignment with a generic patient’s esophagus  708 , showing how the imaging access port  304  is generally aligned with the generic patient’s mouth  800 , and pipe sections  702  and  704  approximate the pathway of the generic patient’s esophagus  708  and lead to the bottom of tank  306  at a position that would be beneath the patient’s heart  802 . In this way, the simulated esophageal access system  700  of  FIG.  7    may provide good ergonomics without leaks and without impacting the realism of the navigation of the imaging device. 
       FIGS.  9  and  10    show certain design parameters selected for the esophageal access system  700  that provide the realistic navigation with improved ergonomics. Such parameters include first and second bends  904  and  906  having radii of curvature (e.g., 67 mm) at the respective proximal and distal ends of the replicated esophageal channel  900 , the length of a conduit  903  between the proximal and distal bends (e.g., 125 mm), and the angle formed between the conduit  903  and the bottom of the tank in the station (e.g., 150 degrees). While these dimensions have proven useful and appropriate for certain implementations, they are not be considered limiting in any way, and may differ, for example, in specialized stations that may be employed for planning or practicing procedures for certain patients, e.g., children, very tall patients, obese patients, etc., whose torso geometries may vary substantially from an average adult patient. In  FIGS.  9  and  10   , portions of the fluid flow control system  909  of station  300  are also shown, as will be described in further detail hereinafter. 
       FIG.  11    shows another view of the esophageal access system  700  in the station  300 , with a cartridge  308  installed in the tank  306  and coupled, at interface port  718 , to vascular access port  706  within the housing.  FIG.  12    shows a cross section of the primary conduit  903  of the replicated esophageal channel  900  with illustrative, non-limiting dimensions. 
     As illustrated in  FIGS.  7 - 11   , the esophageal access system  700  may include first and second pipe sections  702  and  704  within the housing  309 , the first pipe section  702  extending from the esophageal access port  304  on the housing  309  to the second pipe section  704 , and the second pipe section  704  extending from the first pipe section  702  to a first port (at distal end  714 ) in the tank  306 . The first pipe section  702  may include a first bend  904  at a proximal end, and a substantially straight conduit  903  extending from the first bend  904  to the second pipe section  704 . The second pipe section  704  includes a second bend  906 . The second bend  906  may form an angle of between one hundred thirty degrees and one hundred seventy degrees between the substantially straight conduit  903  and a bottom surface (see, e.g., bottom surface  1402  of  FIG.  14   ) of the tank. The esophageal access system  700  may also include a first membrane  711  at the esophageal access port  304  and a second membrane  712  at an interface between the first pipe section  702  and the second pipe section  704 . 
     In patient’s body, a TEE probe will slide along the esophagus, which helps maintain the probe position during the manipulation. As the station esophagus system  700  is not anatomic, the system includes features that reproduce this esophagus “catch” in order to hold the probe in a realistic way. For example, esophageal access system  700  may combine two interchangeable membranes (e.g., latex membranes) located on the way to the tank  306  (e.g., a proximal membrane  711  at the top of the station  300  at the proximal end of the esophageal access system  700 , and a distal membrane  712  just before the tank), as illustrated in  FIG.  13   . These two membranes  711  and  712  may be changed easily in order to be compatible with all probes (e.g., different brands, shrinking sizes, etc.) 
       FIG.  14    shows a top-down view of the station tank  306 , with the patient-specific cardiac model removed. As shown in  FIG.  14   , a recess  1400  is formed in the bottom surface  1402  of tank  306 , into which the TEE probe can extend from the tank port at the distal end  714  of the esophageal access system  700 . In the example of  FIG.  14   , the recess  1400  is wider than the probe  505  allowing the clinician an ability to adjust the probe position within the tank  306  in a realistic manner with realistic movement constraints. 
       FIG.  14    also shows how access port  718  may be formed on a sidewall  1491  of tank  306 . As shown, additional access ports such as access ports  1404  and  1408  can be provided on an opposing sidewall  1489  of tank  306 . Access port  718  may be arranged to interface with a simulated superior vena cava interface on patient-specific cartridge  308 . Access port  1404  may be arranged to interface with a simulated inferior vena cava interface on patient-specific cartridge  308 . Access port  1408  may be arranged to interface with a simulated upper pulmonary vein interface on patient-specific cartridge  308 . 
       FIG.  14    also shows how one or more fluidic openings such as fluidic openings  1406 ,  1410 , and  1412  may be provided in tank  306 , to allow flow of blood simulation fluid  307  around a patient-specific cartridge  308  that is mounted in tank  306  (e.g., in addition to and/or in place of fluid  307  flow into and/or out of the patient-specific structures of cartridge  308  via access ports  1404 ,  1408 , and  718 ). Fluidic openings  1406 ,  1410 , and  1412  may be fluidically coupled to fluid control system  909  (see, e.g.,  FIGS.  9  and  10   ), as described in further detail hereinafter, and may be located at different positions from those shown in  FIG.  14    in some implementations. Access ports  1404 ,  1408 , and  718  may also, or alternatively, be fluidically coupled to fluid control system  909  (see, e.g.,  FIGS.  9  and  10   ), as described in further detail hereinafter. 
       FIGS.  15 A and  15 B  show perspective exploded and perspective views, respectively, of the vascular access system  302  that couples to and extends away from the station  300 . The vascular access system  302  replicates the anatomic and certain biomechanical features of the vascular pathway from the right femoral vein to the inferior vena cava that a clinician would experience in a live procedure. 
     As seen in  FIG.  15   , the proximal end  1500  (e.g., the end configured to be proximal to the clinician during a simulated procedure) of the vascular access system  302  includes sealing membrane  1502  (e.g., a latex seal) that can be punctured by a catheter to simulate the introduction of a catheter into the right femoral vein of a patient (e.g., into the femoral vein and through the skin). As shown in  FIG.  15 B , the vascular access port  310  formed at proximal end  1500  is wide enough to allow for the use of an introducer, which may be needed for certain difficult to catheterize patients. As can be seen in  FIG.  15 A , the sealing membrane  1502  is replaceable by removal of a seal cap  1504  that covers the proximal end  1500  of the vascular access system  302 . The sealing membrane  1502  itself can include several alignment holes  1506  that are aligned with posts  1508  extending upwards from a portion of the proximal end of the vascular access system to ensure proper seal placement. 
     As shown in  FIGS.  15 A and  15 B , the bottom side of the vascular access system  302  includes a number of flanges  1517  extending downwards from the main shaft  1510  to support the vasculature access system at a height over a Cath lab patient table (see, e.g., table  210  of  FIG.  2   ) that would be anatomically appropriate for an average patient. 
     The vascular access system  302  can be constructed of multiple components joined together. The assembly is in some implementations semi-rigid to improve the stability of the device on a work surface (such as a Cath lab table), to reduce the likelihood of cantilevering of the device, and improve durability of the device. The main shaft  1510  includes an interior lumen (not visible in  FIGS.  15 A and  15 B ) of the vascular access system  302 , which can have a substantially constant diameter for the majority, or in some implementations, the entirety of the length of the lumen. 
       FIGS.  16 A and  16 B  show a side view and top view, respectively, of the vascular access system  302 . As can be seen in  FIGS.  15  and  16 B , the vascular access system  302  (e.g., the main shaft  1510  and internal lumen) has a curvature (e.g., including a first or proximal curve  1611  and a second or distal curve  1613 ) that substantially replicates the path of the right femoral vein, iliac vein and inferior vena cava to the right atrium. 
       FIG.  17    shows a top-down cutaway view of the vascular access system  302  coupled to the housing  309  of the station  300  at access port  706 . The access system  302  can be screwed onto the access port  706  of the housing  309 , providing fluidic access between the internal lumen  1700  within main shaft  1510  to the interior of the tank  306 . When a patient-specific cartridge  308  with a patient-specific cardiac model is installed in the tank  306  (as shown in  FIG.  17   ), the coupling between vascular access system  302  and access port  706  of housing  309  provides fluidic coupling between internal lumen  1700  and a portion of the patient-specific model that simulates a portion of the right atrium of the patient. 
       FIG.  18    shows an enlarged view of the access port  706  for connection between the vascular access system  302  and the housing  309  of the station  300 . As shown in  FIG.  18   , the housing access port  706  may be implemented as a dual-lumen pipe  1800 , with a central lumen  1805  allowing a catheter access to a cardiac model within the station tank  306  and to allow fluid to flow into the vascular access system  302  (e.g., into main lumen  1700 ). An outer toroidal chamber  1802  may be provided that surrounds the central lumen  1805  and is fluidically coupled to the central lumen  1805  through an array of through holes  1804 . 
     The holes  1804  (shown in cutaway detail in  FIG.  19   ) may be angled away from the tank  306  of station  300  at, for example, 60 degrees from the horizontal, though the angle can be between 50 and 75 degrees in other implementations. The holes  1804 , in the illustrated implementation, have a diameter of 1.5 mm, but can range from 1.0-2.0 mm in other implementations. The toroidal chamber  1802  is fluidically coupled by a return fluid channel  1702  to the tank  306 . As such, if too much fluid pressure builds up in the vascular access system  302  or in the replicated right atrium, the fluid can escape through the holes  1804  and be rerouted back to the tank  306 . The holes  1804  also provide a route for air bubbles to escape. In some implementations, the hole array only occupies the top half of the wall of the central lumen  1805 . In other implementations, more or less of the wall surface of the central lumen  1805  is occupied by through holes. 
       FIGS.  20  and  21    show two different perspective views of the housing  309  of station  300 , showing the tank  306  at different angles. Also seen in  FIGS.  20  and  21    is an opening  2002  in housing  309  for the proximal end  710  of the esophageal access system  700 .  FIG.  20    shows interface port  718  connecting to the passageway (e.g., central lumen  1805  of access port  706 ) out of the tank  306  to the vascular access system  302 . 
     As illustrated in  FIGS.  20  and  21   , the interior of the tank  306  may be coated with acoustic shielding  2006 . A perspective view of the acoustic shielding  2006  is also shown in  FIG.  22   . The acoustic shielding  2006  may be constructed from ethylene propylene diene monomer (EDPM) rubber, though other polymer coatings with similar acoustic properties could be used instead. The acoustic shield  2006  helps prevent the walls of the tank  306  from impacting the ultrasound images (i.e., by reducing acoustic noise) obtained via the TEE probe. Acoustic output measurements or ultrasonic imaging/testing in general can be strongly affected by reflections or echoes from test tank walls. To overcome this, the tank  306  may be coated with linings of low ultrasonic reflection yet highly absorbent to ultrasound (EDPM is one such material). For example, acoustic shielding  2006  may provide absorption of acoustic energy in the frequency range of 1 MHz &lt; F &lt; 10 MHz (e.g., the frequency range for TEE: Trans Esophageal Echography).  FIG.  23    shows two ultrasound images, including a first image  2300  obtained with a tank that has the acoustic shielding  2006 , and a second image  2302  obtained with a tank that does not have acoustic shielding, to show the impact of the shielding. 
       FIG.  24    shows a cutaway view of the tank  306  with the acoustic shielding  2006 . Also visible in  FIG.  24    are the distal end  714  of the esophageal access system  700 , the recess  1400  in which a TEE probe can positioned after passing through lumen  900 , the access port  706  for coupling to the vascular access system  302 , and a fluid channel  2402  for introducing fluid into the simulated pulmonary vein of the cardiac model (not shown in  FIG.  24   ). As shown, the recess  1400  may be a recess in a bottom wall  2400  of tank  306 . 
     Several studies have shown that cardiac physical models can be conveniently used to evaluate treatment strategies. Most previous studies have been carried out on models obtained using injection molds or additive manufacturing technology, using just one material. The presently disclosed systems and methods utilize a patient-specific cartridge  308  with a patient-specific cardiac model that has the advantages of being arranged for mounting to interface port  718  in tank  306  of station  300 , and of being multi-material. For example, the cardiac model may be derived directly from a patient-specific anatomy into a biomechanical simplified model, approaching the biomechanical behavior of the anisotropic vascular wall material and as well as being, in some implementations, visible under echography. 
       FIG.  25    illustrates an example of a patients-specific cartridge  308  that includes a frame  2500  and a cardiac model  2502 . Of the cardiac model  2502 , one or more, and in some implementations, all of the following components are patient specific: the replicated septum  112 ′, the replicated fossa ovalis  400 ′ of the septum (e.g., both the position and biomechanics of the replicated fossa ovalis  400 ′ may be patient specific for tenting and puncture), a replicated upper 2.5 cm - 5 cm (e.g., 3 cm) of the replicated left pulmonary vein  2505  and the spur (also referred to as a ridge) separating the left pulmonary vein  2505  from the left atrium  2504 , the replicated Left Atrial Appendage  116 ′ (e.g., the position of the LAA  116  and its trabeculae, including both position and biomechanics can be patient specific), and the replicated mitral ring  2503  (e.g., the position of the replicated mitral ring may be patient specific). 
     In some implementations, the cardiac model  2502  may include either patient-specific or standardized portions for a replicated portion  2506  of the right atrium and non-patient specific portions of the left atrium  2504 . 
     A method for fabricating a patient-specific physical cardiac simulation device such as patient-specific cartridge  308  may include segmenting the region of interest from typical medical imaging modalities such as MRI, CT; creating a 3D geometric model from the segmented images, integrating the 3D geometric model to a standard frame, creating a 3D Finite Element model of the anatomical region of interest, assigning realistic material properties from a data-bases of biomechanical cardiovascular tissue model, creating a second 3D Finite Element model, applying a goal-based design optimization algorithm to the second 3D Finite Element model to assign the distribution of printable materials that can replicate the behavior of the first 3D Finite Element model, and printing (e.g., using additive manufacturing techniques) the multi-material model with the frame. More detailed descriptions of this process can be found in PCT Applications WO/2018/050915 and WO/2018/051162, each of which is hereby incorporated by reference in its entirety. 
     In the example of  FIG.  25   , the frame  2500  holds a cardiac model  2502  that includes a portion  2506  corresponding to a patient’s right atrium, a portion  2504  corresponding to the patient’s left atrium, a portion  116 ′ corresponding to the patient’s left atrial appendage  116  extending off from the left atrium that has the shape and biomechanics of the left atrial appendage of the patient, and a portion corresponding to the patient’s pulmonary vein  2505  (positioned behind the left atrial appendage). A portion  400 ′ corresponding to the patient-specific fossa ovalis separates the right atrium from the left atrium. In some implementations, the portion  2506   corresponding to the right atrium need not be patient specific and may have a standard shape and material composition. 
       FIGS.  26 A and  26 B  illustrate perspective and top views, respectively, of another example cardiac model  2502  incorporated into a frame  2500 , according to another implementation. In contrast to the model shown in  FIG.  25   , the cardiac model  2502  shown in  FIGS.  26 A and  26 B  includes a window  2600  in an upper facing-portion of the replicated right atrium  2506 . The window  2600 , formed by an absence of material (for example), provides both visual access to the replicated right atrium  2506  during a planning/practice procedure, as well as improves the ultrasound aspect of the device. In addition, the model  2502  shown in  FIGS.  26 A and  26 B  includes a replicated aortic valve annulus  2602  not seen in  FIG.  25   . In  FIG.  26 B , the replicated fossa ovalis  400 ′ can be seen clearly through the window  2600  formed in the right atrium model portion  2506 , avoiding the need for fluoroscopy during the practice/planning procedure. Finally, the window  2600  provides an avenue for air bubbles to escape the replicated right atrium  2506  that might introduce artifacts in an ultrasound image. 
     The frame  2500  in all of  FIGS.  25 ,  26 A, and  26 B  is shaped such that it curves around the anatomic structures relevant to the procedure to avoid introduction of ultrasound artifacts, while still supporting (but not over-supporting) the cardiac model  2502 . The frame  2500  also has standard dimensions used for all patients, so that the cartridge  308  can be securely positioned within the tank  306  of the station  300  and such that the fluidic channels of fluid control system  909  of the station mate with the model fluid ports connected to the right atrium and pulmonary vein portions  2506  and  2505  of the model  2502  to ensure proper fluid flow through the model. For example, as shown in  FIG.  26 A , frame  2500  may include openings  2609 ,  2611 , and  2613  corresponding, respectively, to the simulated superior vena cava interface, the inferior vena cava interface, and the upper pulmonary vein interface of the patient-specific model  2502 , and respectively, to the access ports  718 ,  1404 , and  1408  in tank  306 . 
     In some implementations, the standard frame  2500  includes the right atrium portion  2506  of the cardiac model  2502 , other than the septum  112 ′ and fossa ovalis  400 ′ separating the right atrium from the left atrium portions of the model. In some examples, the cardiac model cartridge  308  may include a replaceable fossa ovalis  400 ′ to allow a practitioner to practice crossing the septum. The fossa ovalis  400 ′ may include a frame which removably engages with the cartridge  308 . In general, the artificial tissues may range in thickness from between about 0.5 cm to about 2.5 cm. 
     To help provide biomimetic biomechanics of the replicated fossa ovalis  400 ′, in some implementations, additional structural reinforcements are introduced into the model structure. The additional structures allow for bio-realistic tenting and puncturing of the model fossa ovalis  400 ′ during procedures. For example,  FIG.  27 - 1 A  shows a view of the external surface  2702  of the model fossa ovalis  400 ′.  FIG.  27 - 1 B  shows an example view of the interior structure of the model fossa ovalis  400 ′ of  FIG.  27 - 1 A .  FIG.  27 - 1 C  is an enlarged view of  FIG.  27 - 1 B  showing dimensions of the honeycomb structure. 
     In overview, the model fossa ovalis  400 ′ can be constructed from, for example, three or more structural layers, including two outer layers  2702  (e.g., one facing the right atrium and one facing the left atrium), and an inner reinforced layer  2707 . The two outers layers  2702  may be composed of 3D printed acrylate photopolymerized resin having a Young’s modulus comprised from 0.3 GPa to 0.7 GPa and Shore A hardness of between S20 to S95. The inner layer  2707  may be composed of 3D printable material having a Young’s modulus of between 0.2 and 1.0 MPa, and a shore A hardness from 80 to 90. The inner layer  2707  may be a mix between acrylate photopolymerized resins and acrylate based PEG hydrogel (see Table 2). 
     In the example shown in  FIGS.  27 - 1 B and  27 - 1 C , inner reinforced layer  2707  includes an array of polygons including but not limited to honeycomb structures. 
     The thickness and other material and/or mechanical properties of the patient-specific model  2502  may be selected and arranged to provide both a patient-specific flexible septum, and a patient-specific flexible fossa ovalis. More specifically, the flexibility of various portions of patient-specific model  2502  is based on both the shape of the anatomy of the specific patient, and on the mechanical properties of the whole septum structure. As would be understood by one of ordinary skill in the art, the fossa ovalis is a portion of the septum, being defined as an oval/round depression in the lower posterior part of the interatrial septum (e.g., in average 30% of the whole septum area), composed primarily by thin fibrous tissue. 
     For example, in order to form a simulated fossa ovalis  400 ′ for patient-specific model  2502 , the simulated fossa ovalis may be provided with a superior-inferior diameter of, for example, 20.8±6.2 mm, an anterior-posterior diameter of, for example, 15.7±6.2 mm and thickness equal to, for example, 0.68±0.27 mm, the lowest in the whole septum anatomy. Then, moving anteriorly or posteriorly the thickness may increase, with an average value of about, for example, 1.8±0.7 mm. In particular, the simulated septum  112 ′ may be thickest above the fossa ovalis  400 ′ adjacent to superior vena cava entrance  2609  (e.g., 3.4 mm in average); e.g., 1.8 mm thick, in average, in the narrow isthmus anterior to the fossa and in the most inferior portion; e.g., 2.4 mm, in average, in the area immediately inferior to the fossa. 
     In order to provide the simulated fossa ovalis  400 ′ with an adequate flexibility towards a proper patient-specific tenting while providing a more realistic puncturing mechanical feedback to the surgeon during a simulated procedure, the thickness and the material properties of the simulated septum may be arranged to create a gradient zone moving from the outer part of the septum towards the center (fossa ovalis), progressively increasing (e.g., in a direction opposite the radial direction R indicated in  FIG.  27 - 1 A ) the flexibility and the compliance of the model wall, by the arrangement of the materials and/or thicknesses of the model at those locations. For example, the thickness and the material properties the simulated left atrium tissue may be selected based on the strain energy function in Equation 1 below: 
     
       
         
           
             
               
                 W 
                 = 
                 
                   c 
                   
                     10 
                   
                 
                 
                   
                     
                       
                         I 
                         ¯ 
                       
                       1 
                     
                     − 
                     3 
                   
                 
                 + 
                 
                   c 
                   
                     01 
                   
                 
                 
                   
                     
                       
                         I 
                         ¯ 
                       
                       2 
                     
                     − 
                     3 
                   
                 
                 + 
                 
                   c 
                   
                     20 
                   
                 
                 
                   
                     
                       
                         
                           I 
                           ¯ 
                         
                         1 
                       
                       − 
                       3 
                     
                   
                   2 
                 
                 + 
                 
                   c 
                   
                     11 
                   
                 
                 
                   
                     
                       
                         I 
                         ¯ 
                       
                       1 
                     
                     − 
                     3 
                   
                 
                 
                   
                     
                       
                         I 
                         ¯ 
                       
                       2 
                     
                     − 
                     3 
                   
                 
               
             
             
               
                   
                   
                 + 
                 
                   c 
                   
                     02 
                   
                 
                 
                   
                     
                       
                         
                           I 
                           ¯ 
                         
                         1 
                       
                       − 
                       3 
                     
                   
                   2 
                 
               
             
           
         
       
     
      where I 1  and I 2  are invariants of strain, and c ij  are material constants such as the constants provided in Table 1 below. 
     
       
         
          TABLE 1
           
               
               
               
             
               
                 Parameter 
                 Value 
                 Units 
               
             
            
               
                 c 10 
 
                 -5.84× 10 4 
 
                 Pa 
               
               
                 c 01 
 
                 6.34 × 10 4 
 
                 Pa 
               
               
                 c 20 
 
                 1.60 × 10 7 
 
                 Pa 
               
               
                 c 11 
 
                 -3.53 × 10 7 
 
                 Pa 
               
               
                 c 02 
 
                 1.97×10 7 
 
                 Pa 
               
            
           
         
       
     
     The mechanical features of the simulated septum  112 ′ are arranged to mimic biological soft tissue, particularly with respect to the interatrial septum fibers, which have a hierarchical microstructure that results in hyperelastic properties. These mechanical features of the simulated septum  112 ′ allow the patient-specific cartridge  308  to mimic a patient’s actual transseptal tenting and puncture for clinicians training and/or patient-specific rehearsal. The mechanical features of the simulated septum  112 ′ may be arranged to be nearly isotropic and hyperelastic. Accordingly, in some implementations, the simulated fossa ovalis  400 ′ of patient-specific model  2502  may be isotropic and hyperelastic with a flexibility gradient of decreasing flexibility with increasing radial distance from the center of the fossa ovalis. 
       FIG.  27 - 1 C shows a more detailed geometry of the honeycombs  2709  that may be included in inner reinforced layer  2707 , and that may be arranged (e.g., along with the thickness and material properties of the surrounding layers) to provide the patient-specific flexibility and tenting characteristics of the simulated septum  112 ′ and fossa ovalis  400 ′ of the patient-specific model. For example, each polygon  2709  can be hexagonal in shape, with a diameter D ( FIG.  27 – 1 C  measured from diametrically opposing corners of the hexagon (ranging from around 5.0 mm to about 6.0 mm. The honeycomb  2709  can be fabricated, for example, from Acrylonitrile butadiene styrene (ABS) or the like relatively stiff materials where “stiff” is understood to be a material with a Young’s Modulus greater than 100 MPa, for example, a Young’s Modulus of between about 1-2 GPa. The distance (d) between cells (i.e., the in-plane thickness of the edges of each honeycomb) can range from about 0.4 to about 0.5 mm. The out-of-plane thickness of the honeycomb (which corresponds to the thickness of the entire inner layer) is about 0.3 mm to about 0.4 mm (e.g., 0.36 mm). The space  2710  within the honeycomb structure  2709  can be filled with elastic Acrylate photopolymerized resin, such as Agilus PolyJet material or the like relatively soft material where “soft” is understood to be a material having a Young’s Modulus of between about 0.3-7 MPa. The specific materials utilized are unimportant and other materials may be substituted so long as the Young’s modulus of these materials is roughly approximated. The inner and outer layers 700&#39;A and 400&#39;B of the model fossa ovalis  400 ′ can also be formed of elastic Acrylate photopolymerized resin such as Agilus PolyJet or like soft material, and have a thickness of between about 0.30 mm and 0.35 mm (e.g., 0.32). Together the model fossa ovalis  400 ′ may be about 1 mm thick, though thickness may be varied based on the specific anatomy of the patient. In some embodiments, inner reinforced layer  2707  may include 1% to 40% of the elastic Acrylate photopolymerized resin. For example, the space  2710  within the honeycomb structure  2709  may include 1% to 40% of the elastic Acrylate photopolymerized resin. In some embodiments, the inner and outer layers 700&#39;A and 400&#39;B of the model 
     The remaining patient-specific portions of the cardiac model  2502  can be made from a combination of materials determined using the above-referenced optimization process (discussed further in PCT Applications WO/2018/050915 and WO/2018/051162) to obtain tissues that have shapes and biomechanical characteristics substantially similar to that of the actual patient’s anatomy. Typical replicated anatomical wall thicknesses range from about 0.5 to about 2.5 cm. In some implementations, as described further in U.S. Pat. Application No. 16/417,151, hereby incorporated herein by reference in its entirety, the materials can further be selected to achieve an ultrasound aspect that is substantially similar to that of the actual specific patient. 
     In the example of  FIGS.  27 - 1 A through  27 - 1 C , the patient-specific model  2502  includes a fossa ovalis  400 ′ having a flexibility corresponding to a flexibility of a fossa ovalis of the heart of the patient (e.g., a flexibility that decreases with increasing radial distance from a center thereof, such as according to the decreasing flexibility of the fossa ovalis of the patient with the same increasing radial distance). 
       FIGS.  27 - 1 D  though   27 - 1 H  shows another example of middle layer 400′C which replaces the honeycomb  2709  structure of  FIGS.  27 - 1 B and  27 - 1 C with bands of fiber  2709 ′. According to one example, the fiber  2709 ′ is generally flat and formed as concentric, closed curve. In some examples, the fibers  2709 ′ may have a width of between 0.5 and 0.8 mm, a thickness of between 0.2 mm and 0.4 mm, and may be formed of a stiff material such as stiff Acrylate photopolymerized resin. The fibers  2709 ′ may have a Young’s modulus of between 1 and 2 GPA, and a Shore D hardness of between 20 and 95. The area or space  2710 ′ adjacent the fiber  2709 ′ may be composed of a soft material such as a mixture of elastic Acrylate photopolymerized resin (e.g., Agilus® PolyJet) and Hydrogel. See Table 2. Again, the specific materials used for  2709 ′ and  2710 ′ is unimportant so long as the Young’s modulus is roughly the same. According to one example, the space  2710 ′ is composed of between 95%-100% Agilus (by weight) with the balance (if any) formed of Hydrogel. According to one example, three fibers  2709 ′ are provided with fiber 2709′-1 have a radius r-1 which is 20% of the radius Rfo of the fossa ovalis, fiber 2709′-2 have a radius r-2 which is 50% of the radius Rfo of the fossa ovalis, and fiber 2709′-3 have a radius r-3 which is 80% of the radius Rfo of the fossa ovalis. 
     Like the preceding example, the fossa ovalis  400 ′ according to this example includes inner and outer layers 400&#39;A, 400&#39;B which may be formed of a soft material. The inner and outer layers 400′A, 400′B may have a thickness of 0.35 mm, and the middle layer 400′C may have a thickness of between 0.2 mm and 0.3 mm. 
     The changes in the structure of the fossa mainly concern the “sandwich”. Table 2 sums up the material proportion for different materials tested. Some of the materials tested have better properties regarding absorption of water which lead to better RF conductivity of the material. This is highlighted in Table 3. 
     
       
         
          TABLE 2
           
               
               
               
               
               
               
               
             
               
                 Material 
                 M1 
                 M2 
                 M3 
                 M4 
                 M5 
                 M6 
               
             
            
               
                 % hydrogel 
                 8.6 
                 18.4 
                 28.3 
                 17.11 
                 26.32 
                 15.74 
               
               
                 % Stiff acrylate photopolymerized resin (Vero) 
                 0 
                 0 
                 0 
                 1.81 
                 2.40 
                 3.18 
               
               
                 % Soft acrylate photopolymerized resin (Agilus) 
                 91.4 
                 81.6 
                 71.7 
                 81.08 
                 71.28 
                 81.08 
               
            
           
         
       
     
     
       
         
          TABLE 3
           
               
               
               
               
               
             
               
                 Results of Baylis experimental tests using a saline water of 1% 
               
               
                 ID 
                 Thickness 
                 Material 
                 Pulse time to cross 
                 Constant time to cross 
               
             
            
               
                 CA 
                 1 mm 
                 Sandwich M1 (LAACS) 
                 1 sec 4 sec 
                 8 sec 6 sec 
               
               
                   
               
               
                 CB 
                 1 mm 
                 Sandwich M2 
                 1 sec 2 sec 2 sec 
                 3 sec 1 sec 2 sec 
               
               
                   
               
               
                   
               
               
                 CC 
                 1 mm 
                 Sandwich M2 
                 1 sec 2 sec 2 sec 
                 4 sec 1 sec 
               
               
                   
               
               
                   
               
               
                 BA 
                 2 mm 
                 M1 
                 4 sec 5 sec 1 sec 
                 5 sec 8 sec 1 sec 
               
               
                   
               
               
                   
               
               
                 BB 
                 2 mm 
                 M2 
                 3 sec 2 sec 2 sec 1 sec 
                 3 sec 3 sec 2 sec 
               
               
                   
               
               
                   
               
               
                   
               
               
                 BC 
                 2 mm 
                 M3 
                 Needle went through without RF 1 sec 2 sec 1 sec 
                 Needle went through without RF 
               
               
                   
               
               
                   
               
               
                   
               
               
                 BD 
                 2 mm 
                 M4 
                 2 sec 2 sec 1 sec 
                 1 sec 1 sec 2 sec 
               
               
                   
               
               
                   
               
               
                 BE 
                 2 mm 
                 M5 
                 1 sec 
                 Needle went through without RF 
               
            
           
         
       
     
     Radiofrequency puncture systems (like the Baylis system) (https://www.baylismedical.com/products/specialty-devices/rfp-100a-rf-puncture-generator/ ) applies to coagulation induced by all electromagnetic energy sources with frequencies less than 900 kHz, although most devices function in the range of 375-500 kHz. The term RF refers not to the emitted wave but rather to the alternating electric current that oscillates in this frequency range. In monopolar RF ablation, the patient is part of a closed-loop circuit that includes an RF generator, an electrode needle, and a large dispersive electrode (ground pads). An alternating electric field is created within the tissue of the patient. Because of the relatively high electrical resistance of tissue in comparison with the metal electrodes, there is marked agitation of the ions present in the target tissue. 
     The thermal damage caused by RF heating produces irreversible cellular damage allowing the needle to go through the tissue. 
     For cardiology application the radiofrequency is used to cross the septum. For 3D printed model or silicone-based model, these systems don’t work as the electric loop is not closed because of the non-conductivity of the material. 
     The disclosed implementation of two layers of Acrylic photopolymerized material encasing and hydrogel, the septum absorbs and retains water making the system compatible with RF. 
     Putting saline water of 1% of concentration in the simulation system tank allows our system to be compatible with radiofrequency because our septum has enough electrical conductivity to close the loop. The table 3 show septum crossing with RF for different implementation. 
     Example configuration BA allows more realistic tenting and use RF to go through the fossa. 
       FIG.  27 - 2 A  shows an example cardiac model cartridge  308  with the removable septum cartridge  308 ′ removed, and  FIGS.  27 - 2 B,  27 - 2 C  shows the example cardiac model cartridge  308  of  FIG.  27 - 2 A  with the removable septum cartridge  308 ′ installed. 
       FIG.  27 - 2 D  is a graph illustrating the difference in mechanical properties between the honeycomb structure of  FIG.  27 - 1 B  and the concentric closed-shape structure of  FIG.  27 - 1 D ). The graph compares the maximum stress changes into the fossa with different structures. To do so, a first simulation was conducted with a mono material and unstructured fossa as a base. Then, the fossa with honeycomb and concentric structures were simulated. The graph highlights the fact that concentric closed-shape structure of  FIGS.  27 - 1    decreases more and more the maximum stress along iterations compared to honeycomb structure that increases maximum stress by 13% for every iteration. 
     A simple ellipse punctured 1 mm thick has been designed (fossa average thickness) including different structures (see  FIGS.  27 - 3 A-  27 - 3 C ). Distance between structure is the same for both  FIGS.  27 - 3 A and  27 - 3 B  because it is dependent of the dilator diameters (5F to 10F i.e., D1.67 mm to D3.3 mm), the only variable is the thickness of the structure, as seen below in Table 4: 
     
       
         
          TABLE 4
           
               
               
             
               
                 Concentric circle 
                 Walls 
               
             
            
               
                 0.5 mm 
                 0.375 mm 
               
               
                 0.8 mm 
                 0.75 mm 
               
               
                 1.5 mm 
                 1.1 mm 
               
            
           
         
       
     
     For the honeycomb structure, the dimension was taken from the actual solution in ABS. 
     
       
         
          TABLE 5
           
               
               
               
             
               
                 Test 
                 Objective 
               
               
                 Reduce max and mean mises stress in anatomy geometry         Δ   %     =         σ     s   t   r   u   c   t   u   r   e   d       m   a   x       −     σ     m   o   n   o   m   a   t       m   a   x             σ     m   o   n   o   m   a   t       m   a   x           ∗   100       
 
               
               
                   
                 Mean stress 
                 Max stress 
               
             
            
               
                 Circular structure 0.5 mm thick 
                 12% 
                 -17% 
               
               
                 Circular structure 0.8 mm thick 
                 17% 
                 -29% 
               
               
                 Circular structure 1.1 mm thick 
                 31% 
                 -17% 
               
               
                 Wall structure 0.375 mm thick 
                 12% 
                 -5% 
               
               
                 Wall structure 0.75 mm thick 
                 33% 
                 -8% 
               
               
                 Wall structure 1.5 mm thick 
                 42% 
                 7% 
               
               
                 Honeycomb structure (actual) 
                 12% 
                 11% 
               
            
           
         
       
     
     As seen above in Table 5, only the wall structure of 1.5 mm thickness and the honeycomb structure does not decrease the maximum stress for 1.5 mm of displacement. For each test case, the maximum stress has been verified to be under the tensile strength. 
       FIG.  28    shows three images  2800 A,  2800 B, and  2800 C of an example cardiac model cartridge  308  under ultrasound, demonstrating the biomimetic ultrasound response of the model. In various scenarios, the surgical simulation device  202  may be used by providing a surgical simulation device  202  having a station  300  having a housing  309 , a tank  306  formed in the housing  309 , and a vascular access system  302  coupled to the housing  309 , providing, in the tank  306 , a patient-specific cartridge  308  that includes a patient-specific model  2502  of at least a portion of a heart of a patient, inserting an imaging device (e.g., TEE probe  505 ) through an esophageal access system  700  within the housing  309  from an esophageal access port  304  on the housing  309 , though a first port (at end  714 ) in the tank  306 , and into a recess  1400  in a bottom surface  1402  of the tank  306  beneath the patient-specific cartridge  308 , and inserting a surgical element (e.g., a guidewire, a tool, etc.) from a vascular access port  310  of the vascular access system  302 , through a main lumen  1700  of the vascular access system  302 , and into a portion of the patient-specific model  2502  via a second port  718  in the tank  306 . The imaging device may then be operated to capture images such as ultrasound images  2800 A,  2800 B, or  2800 C, to aid in manipulating the surgical element to, through, around, or within various portions of the patient-specific model. 
       FIG.  29    shows an example entry to the replicated left atrial appendage  116 ′ to be occluded during example procedures contemplated to be carried out using the station  300  and cartridges  308  disclosed herein. As can be seen in  FIG.  29   , the interior surface  2900  of replicated left atrial appendage  116 ′ may include a micropattern of small depressions  2902 . The depressions  2902  shown in  FIG.  29    are circular in shape, though other regular or irregular geometric shapes may also be used. Each depression  2902  can be between about 0.1 mm and 1.0 mm in diameter and be between 0.1 mm and 2.0 mm deep. The micropattern improves the ability for atrial appendage occluders to anchor to the simulated tissue. In various implementations, the micropattern may extend to from about 1.0 cm to about 2.5. cm into the model left atrial appendage  116 ′. 
       FIG.  30    illustrates a portion of a patient heart that can be modeled by a patient-specific model of a patient-specific cartridge of a physical simulator device, according to aspects of the disclosure. For example,  FIG.  30    shows a patient’s fossa ovalis  3000 , and various potential puncture locations thereon, relative to other cardiac structures such as the coronary sinus ostium (CS Os)  3002 , right atrium (RA), and inferior vena cava (IVC), and indicates the radial direction R′ of the patient’s negative flexibility gradient, corresponding to the radial direction R of the flexibility gradient of the simulated fossa ovalis  400 ′ described above in connection with  FIG.  27 – 1 D . 
     As described above in connection with, for example,  FIGS.  26 A and  26 B , patient-specific cartridge  308  may include a patient-specific model  2502  coupled to a frame  2500 . In some implementations, the frame  2500  is a standard frame that can carry various different patient-specific models.  FIG.  31    illustrates a perspective view of a patient-specific cartridge having a standard frame, according to aspects of the disclosure. As shown in  FIG.  31   , patient-specific model  2502  may include a patient-specific portion (e.g., including the simulated right atrium  2506 , the simulated left atrium  2504 , the simulated aortic annulus  2602 , and the left atrial appendage  116 ′) in which the shape, mechanical properties, acoustic properties, and/or other properties correspond to the same properties of a specific patient. The patient-specific model  2502  may also include interfacing portions such as interfacing portions  3100 ,  3102 , and  3103  that may deviate, in shape, size, orientation, and/or mechanical properties, from the corresponding properties of the patient, in order to interface with standard frame  2500 . As shown in  FIG.  31   , standard frame  2500  may include a base portion  3108 , a rear portion  3112 , and front support  3110  surrounding opening  2609  (e.g., corresponding to a superior vena cava interface for patient-specific cartridge  308 ). As shown, interfacing portion  3100  extends between the patient-specific portion of patient-specific model  2502  and opening  2609  of frame  2500 . Interfacing portions  3100 ,  3102 , and  3103  may be integrally formed portion of a contiguous patient-specific model  2502 , though they may deviate from the patient’s anatomical shape. 
       FIG.  32    illustrates a perspective view of the standard frame  2500  of  FIG.  31   , with the patient-specific model removed. As shown in  FIG.  32   , rear portion  3112  may include two additional openings  2611  and  2613 . As shown in  FIG.  32   , a curved support structure  3207  may also extend from rear portion  3112  for supporting and/or orienting patient-specific model  2502  on the frame. 
       FIG.  33    illustrates a perspective view of a patient-specific cartridge  308  having a patient-specific model  2502  coupled to a standard frame  2500  in an orientation in which an upper pulmonary vein interface portion  3102  of patient-specific model  2502  extends between the patient-specific portion of patient-specific model  2502  and opening  2613  in frame  2500 . Because interfacing portions  3100 ,  3102 , and  3103  are allowed to deviate from the patient-specific shape of the patient-specific portion, each patient-specific model  2502  is arranged to include features that anatomically, mechanically, and/or acoustically correspond to a particular patient, while coupling to the same standard frame  2500 , which reduces cost, and increases ease of use of the simulator device  202 . 
     For example,  FIG.  34    illustrates a patient-specific cartridge  308  having another patient-specific model  2502  coupled to the standard frame  2500 . As shown in  FIG.  34   , the patient-specific portion of patient-specific model  2502  is different from that of  FIG.  33   , resulting in interfacing portions  3100 ′,  3102 ′, and  3103 ′ having different shapes from portions  3100 ,  3102 , and  3103  of  FIG.  33    that allow interfacing to the same standard openings  2609 ,  2611 , and  2613  of the same standard model  2500 . 
       FIG.  35    illustrates a patient-specific model  2502 , emphasizing the patient-specific portion(s) of the model, which may include the simulated right atrium  2506 , aorta  2602 , left atrium  2504 , and left atrial appendage  116 ′.  FIG.  36    illustrates three different patient-specific models  2502 A,  2502 B, and  2502 C, each having different patient-specific features (e.g., patient-specific right atria  2506 , aortas  2602 , left atria  2504 , and left atrial appendages  116 ′) that match the anatomical, mechanical, and acoustic characteristics of the corresponding features of a particular patient, and each having different interfacing portions  3100 ,  3102 , and  3103  that allow the different patient-specific features to interface with the same standard frame  2500 . As shown, the three different patient-specific models  2502 A,  2502 B, and  2502 C can be coupled to a standard frame  2500  to form three different patient-specific cartridges  308 A,  308 B, and  308 C. 
     For example,  FIG.  37    shows how a patient-specific model  2502  can have an integrally formed upper pulmonary vein interfacing (coupling) portion  3102  that deviates from the patient’s anatomical form and extends between the patient-specific portion and opening  2613 . Arrow  3700  indicates that the interfacing portion  3102  is a supplemental piece of the patient-specific model  2502 , though the patient-specific portion and the interfacing portion  3102  can be formed in a common manufacturing process (e.g., an additive manufacturing process). 
     As illustrated in, for example,  FIGS.  31 - 37   , a patient-specific cartridge  308  for a surgical simulator device  202  may include a patient-independent (e.g., standard) frame having first, second, and third openings  2609 ,  2611 , and  2613 , and a patient-specific cardiac model  2502 . The patient-specific cardiac model  2502  may include a right atrium  2506 , a left atrium  2504  and a septum  112 ′ having mechanical and anatomical shape properties that correspond to the mechanical and anatomical shape properties of the left atrium  102  and the septum  112  of a patient, a superior vena cava interfacing portion  3100  that deviates from the anatomical shape of the superior vena cava of the patient and extends between the right atrium  2506  and the first opening  2609  in the patient-independent frame  2500 ; an inferior vena cava interfacing portion  3103  that deviates from the anatomical shape of the inferior vena cava of the patient and extends between the right atrium  2506  and the second opening  2611  in the patient-independent frame  2500 , and an upper pulmonary vein interfacing portion  3102  that deviates from the anatomical shape of the pulmonary vein of the patient and extends between the left atrium  2504  and the third opening  2613  in the patient-independent frame  2500 . The patient-specific cardiac model  2502  may also include a left atrial appendage  116 ′ having mechanical and anatomical shape properties that correspond to the mechanical and anatomical shape properties of the left atrial appendage  116  of the patient. 
       FIGS.  38 A and  38 B  respectively illustrate misaligned patient-specific superior vena cava and inferior vena cava interfacing portions  3802  and  3800  that do not align with standard frame  2500 , and corresponding interfacing portions  3100  and  3102  of a patient-specific model that deviate from the patient-specific forms of  3802  and  3800  to couple to openings  2609  and  2611  of a standard frame  2500 .  FIG.  39    illustrates another view of the misaligned patient-specific superior vena cava and inferior vena cava interfacing portions  3802  and  3800  (shown in partial transparency), the corresponding interfacing portions  3100  and  3102  coupled to openings  2609  and  2611 , and an additional portion  3900  of the model that can be removed or omitted to form an opening  2600  into the right atrium of the model. 
       FIG.  40    illustrates various aspects of a process for manufacturing a patient-specific cardiac model  2502  for coupling to a standard frame  2500 , according to aspects of the disclosure. As indicated in  FIG.  40   , during the design phase of the manufacturing process for a particular patient-specific model  2502 , the virtual patient-specific model may include patient-specific superior vena cava portion  3802 , patient-specific inferior vena cava portion  3800 , and patient-specific upper pulmonary vein portion  4003 , which would be misaligned with openings  2609 ,  2611 , and  2613  of standard frame  2500 . These patient-specific features can be generated based on images and/or other measurements of the size, shape, orientation, thicknesses, and/or other properties of the patient’s actual cardiac structures. As shown, three interfaces between the virtual patient-specific model and three planes  4000 ,  4002 , and  4004  may be identified. Portions  3800 ,  3802 , and  4003  extending beyond respective planes  4000 ,  4002 , and  4004  may be removed, and interfacing portions  3011 ,  3102 , and  3103  can be designed to extend between the identified planar interfaces and the known locations of standard frame openings  2609 ,  2611 , and  2613 . Once these interfacing portions  3011 ,  3102 , and  3103  are designed into the virtual model, the entire patient-specific model including these portions can be generated (e.g., in an additive manufacturing, molding, or other suitable manufacturing process). 
     As shown in the various examples shown in  FIGS.  31 ,  33 ,  35 ,  36 ,  39 , and  40   , the patient-specific cartridge  308  can be provided with a frame  2500  configured to couple the patient-specific model  2502  to the tank  306 . The frame  2500  can include first, second, and third openings  2609 ,  2611 , and  2613  configured to align with first, second, and third access ports  718 ,  1404 , and  1408  in the tank. As shown in these examples, the patient-specific model  2502  may include a patient-specific portion that corresponds to the anatomical shape of the corresponding portion of the heart of the patient, and first, second, and third interfacing portions  3100 ,  3103 , and  3102  that deviate from the anatomical shape of the corresponding portions of the patient’s heart to extend between the patient-specific portion and the first, second, and third openings  2609 ,  2611 , and  2613 . The first, second, and third interfacing portions  3100 ,  3103 , and  3102  may correspond, respectively, to a superior vena cava interfacing portion, an inferior vena cava interfacing portion, and an upper pulmonary vein interfacing portion of the patient-specific model. The patient-specific model  2502  may include a simulated right atrium  2506  having a window  2600 . 
     Various examples discussed herein describe the advantages of providing a patient-specific model  2502  with acoustic features that mimic the acoustic features of the corresponding patient cardiac structures (e.g., for ultrasound imaging during a simulated surgical procedure). In some circumstances, it can also be beneficial to be able to provide a physical simulator device in which features of the patient’s anatomy mimic the response of various anatomical features to other imaging technologies. 
     For example, during some cardiac interventions, x-ray imaging can be performed to help a surgeon more accurately understand the location of a guidewire or other surgical device.  FIG.  41    illustrates, for example, a fluoroscopic image of an LAA closure device  502  being installed within a patient’s heart, in which the shadow  4102  of the patient’s heart and a shadow  4104  of the patient’s spine can be seen. These shadows, while faint, can be helpful to a surgeon, in addition to ultrasound imaging with ultrasound probe  505 . However, as shown in  FIG.  42   , unless the patient-specific model  2502  and/or other portions of station  300  are provided with x-ray interactive features, while the ultrasound probe  505 , and a guidewire  507  can be seen in a fluoroscopic image  4200  of device  202 , image  4200  does not include the shadows  4102  and  4104 . In order to include these fluoroscopic shadow features, patient-specific model  2502  and/or portions of station  300  can be provided with x-ray interactive features. 
       FIG.  43    illustrates a cross-sectional view of a portion of a wall of a patient-specific model  2502  of a patient’s heart. As shown in  FIG.  43   , the walls of patient-specific model  2502  may be formed (e.g., in a three-dimensional printing process) from an inner polymer (e.g., PolyJet) layer  4302 , an outer polymer (e.g., PolyJet) layer  4300 , and a hydrogel layer  4303  interposed between the inner and outer layers  4302  and  4300 . For example, inner layer  4302  and outer layer  4300  may be formed from PolyJet materials (e.g., Stratasys resins) that encapsulate hydrogel layer  4303 . In various implementations, hydrogel layer  4303  may be used as a sacrificial support material or may be used to absorb an injected aqueous liquid such as an x-ray absorbent liquid. Layers  4300 ,  4302 , and/or  4303  may be arranged to mechanically and/or acoustically mimic the anatomical features of patient cardiac structures. 
     In order to provide a patient-specific model  2502  that generates a cardiac shadow similar to cardiac shadow  4102  of  FIG.  41   , the patient-specific model  2502  may be provided with x-ray interactive material. For example, as shown in  FIG.  44   , patient-specific model  2502  may be provided with an x-ray interactive coating  4400  (e.g., an x-ray absorbent coating such as an iodine coating, a barium coating such as a barium sulfate paint, a calcium phosphate coating, a radio opaque ink, a metal coating, a hydrophilic coating, and/or any combination thereof) on outer polymer layer  4300  (and/or on inner layer  4302 ). 
     Additionally, or alternatively, hydrogel layer  4303  may be injected with an x-ray interactive material (e.g., a contrast liquid including calcium, iodine, and/or barium such as Iohexol).  FIG.  45    illustrates a process for injecting a light-reactive material such as an x-ray interactive material into a wall of a patient-specific model of a patient’s heart, according to aspects of the disclosure. As shown in  FIG.  45   , layer  4303  may be injected with an x-ray absorbent aqueous liquid to form an x-ray absorbing internal layer  4502  for patient-specific model  2502 . The injected X-ray absorbent aqueous liquid may diffuse inside the hydrogel layer  4303  to obtain a homogenous X-ray absorption characteristic all over the model  2502  to reproduce the heart shadow described above in connection with  FIG.  41   . Coating and/or injection of x-ray absorbent materials for patient-specific model  2502  can be performed during a post-processing of the model (e.g., following an additive manufacturing process to generate the model). In the example of  FIG.  45   , the patient-specific model  2502  includes at least one wall portion having an outer layer  4300 , an inner layer  4302 , and an x-ray absorbent material  4502  interposed between the outer layer and the inner layer. 
     The features described above in connection with  FIG.  44    and/or 45 may provide patient-specific cartridge  308  with fluoroscopic features that cause the patient-specific model  2502  to generate a cardiac shadow similar to cardiac shadow  4102  of  FIG.  41   , under x-ray imaging of station  300  and cartridge  308  installed therein. 
       FIG.  46    illustrates a perspective view of a spinal shadow card  4600  that can be provided in station  300  to generate, under x-ray imaging, a spinal shadow similar to spinal shadow  4104  of  FIG.  41   , according to aspects of the disclosure. The shadow of the spine is used during the procedure by the clinician to estimate where the catheter is inside the right atrium. By knowing over which vertebra the catheter is, the surgeon is able to understand whether they are in front of the septum to initiate a transseptal puncture, for example. 
     As shown in  FIG.  46   , spinal shadow card  4600  may include a substrate  4602  and a spinal simulation feature  4604  formed on the substrate. Spinal simulation feature  4604  may be printed on, embedded within, etched in, or otherwise formed on or in substrate  4602 . For example, spinal simulation feature  4604  may be a radio opaque ink printed on an x-ray transparent substrate  4602 . Spinal simulation feature  4604  may be patient-specific or may represent the geometrical shape of a shadow of a generic patient (e.g., to a C-ARM fluoroscopy instrument at least at 0 degrees during the catheter navigation in the right atrium). 
       FIG.  47    illustrates a side view of a station  300  of a physical simulator device  202  showing how a spinal shadow card  4600  may be disposed within the station beneath bottom wall  4700  of tank  306 . In this arrangement, a spinal simulation card is disposed outside the tank adjacent to a bottom wall of the tank, and an x-ray image of station  300  will include a simulated spinal shadow caused by spinal simulation features  4604 . 
     As illustrated by  FIG.  47   , a surgical simulation device  202  may be provided that includes a station  300  having a housing  309 , a tank  306  formed in the housing and configured to receive a patient-specific cartridge  308  that includes a patient-specific model  2502  of at least a portion of a heart of a patient, where the tank  306  has a bottom wall  4700  having a first surface that forms a bottom surface  1402  of the tank, and an opposing second surface, an esophageal access system  700  extending within the housing between an esophageal access port  304  on the housing and a first port  714  in the tank, a vascular access system  302  including a first end with a vascular access port  310  and a second end configured to be fluidly coupled to a second port  718  in the tank, and a spinal shadow simulation card  4600  disposed within the housing  309  adjacent the opposing second surface of the bottom wall  4700  of the tank. The patient-specific model  2502  includes mechanical and acoustic features that correspond to mechanical and acoustic features of the heart of the patient. The esophageal access system  700  is configured to allow access to the tank  306  by an ultrasound probe  505  for ultrasound imaging of the patient-specific cartridge  308 . 
       FIGS.  48 - 57    illustrate various aspects of fluid flow control system  909  of a physical simulator device  202 . For example,  FIG.  48    illustrates a schematic view of a fluid flow control system  909  that includes an outlet pipe  4804  and an inlet pipe  4814  fluidly coupled to tank  306  via openings  4800  and  4802  of a physical simulator device  202  (e.g., corresponding to openings  1406  and  1410  of  FIG.  14   , respectively). In the example of  FIG.  48   , outlet pipe  4804  includes a filter  4806 , and a pump  4808  that controls the flow of blood simulation fluid  307  through pipes  4804  and  4814  and tank  306 . In the example of  FIG.  48   , inlet pipe  4814  includes a chamber  4810  having an air cavity  4812  for removal of air bubbles from the blood simulation fluid  307  that could otherwise negatively impact ultrasound imaging. 
       FIG.  49    illustrates a schematic view of another implementation of fluid flow control system  909  in which an additional outlet pipe  4909  extending between additional opening  4905  to filter  4806 , and a heater  4900  coupled to a power supply  4902  are provided. Heater  4900  may be powered by power supply  4902  (e.g., a battery within station  300 ) to heat blood simulation fluid  307  (e.g., to approximately 37.5° C.). 
     In the examples of  FIGS.  48  and  49   , a fluid control system  909  is provided in the station  300 , and configured to circulate a blood simulation fluid  307  through the tank  306  at least a portion of the patient-specific model  2502 . The fluid control system  909  includes an outlet pipe (e.g., pipe  4804  and/or  4909 ) coupled to a first opening (e.g.,  4800  or  4905 ) in the tank, an inlet pipe (e.g., pipe  4814 ) coupled to a second opening (e.g., opening  4802 ) in the tank, and a pump  4808  configured to move the blood simulation fluid  307  through the inlet pipe, the tank, and the outlet pipe. The fluid control system  909  may also include a filter  4806  on the outlet pipe. The fluid control system may also include a heater  4900  disposed between the pump  4808  and the second opening. The fluid control system  909  may also include a chamber  4810  having an air cavity  4812  disposed between the pump and the second opening and/or between the heater and the second opening. 
       FIG.  50    schematically illustrates additional features of the heating system for station  300 , according to aspects of the disclosure. 
       FIG.  51    illustrates a perspective view of an accessory fluid heater  5100  that can be provided for a physical simulator device  202 , according to aspects of the disclosure. As shown in  FIG.  51   , in one implementation, an accessory heater  5100  may include a mounting structure  5102  configured to removably attach to a sidewall  5110  of station  300 , and configured to hold a temperature sensor  5104 , and a resistive heating element  5106  within fluid  307  in tank  306 . 
       FIG.  52    illustrates a cross-sectional view of a mounting member  5102 , installed on sidewall  5110  of station  300 . As shown in  FIG.  52   , mounting member  5102  may be arranged to wrap around and over the top of sidewall  5110  (e.g., secured by a friction fit), while holding temperature sensor  5104  and resistive heating element  5106  in a desired position. Resistive heating element  5106  may be provided in tank  305 , in a feedback loop with temperature sensor  5104 , to rapidly heat the blood simulation fluid  307  (e.g., to 37.5° C.) prior to a simulated surgical procedure, the fluid thereafter being held at the desired temperature by internal heater  4900  (see  FIG.  49   ). Resistive heating element  5106  may be powered by an external power source  5108 . 
       FIGS.  53 A,  53 B, and  53 C  illustrate various features of another implementation of an accessory heater for physical simulator device  202 . 
     For example, as shown in  FIG.  53 A , an accessory heater  5300  may be provided that includes two mounting portions  5304 , configured to wrap around and over opposing sidewalls  5110  and  5112  of station  300 , and a cap portion  5302  extending between the two mounting portions  5304 . 
       FIG.  53 B  illustrates a cross-sectional view of a mounting portion  5304  of the accessory fluid heater  5300  of  FIG.  53 A . As shown in  FIG.  53 B , mounting portion  5304  may include a first vertical extension  5308  having a first magnet  5306  and a second vertical extension  5310  having a second magnet  5313 . As shown, sidewall  5112  of tank  306  may include magnets  5309  and  5311  configured to magnetically engage with magnets  5306  and  5313  of mounting portion  5304  to temporarily secure accessory heater  5300  to tank  306 . Sidewall  5110  may include magnets similar to magnets  5309  and  5311 , for magnetically engaging with magnets in the other mounting portion  5304  of accessory heater  5300 . As shown in  FIG.  53 C , a resistive heating element  5390  may extend from cap portion  5302  into blood simulation fluid  307  (when mounting portions  5304  are mounted to sidewalls  5110  and  5112 ) to rapidly heat fluid  307  (e.g., to 37.5° C.) prior to a simulated surgical procedure. 
     As shown in  FIG.  54   , physical simulator device  202  may include a flush system  5400  configured to couple to station  300  for flushing blood simulation fluid  307  from station  300 . As shown in  FIG.  54   , flush system  5400  may include external flush tubing  5404  that extends between a flush valve  5402  and a flush receptacle  5406 . 
       FIG.  55    shows how, internally to station  300 , fluid flow system  909  may include a Y-pipe  5500  at an intersection between outlet pipe  4804  and inlet pipe  4814  before flush valve  5402 .  FIG.  55    includes arrows that illustrate the fluid flow within outlet pipe  4804  and inlet pipe  4814  (noting that other features of fluid control system  909  such as heater  4900 , pump  4808 , and chamber  4810  are not shown in  FIG.  55    for clarity of the present description) when flush valve  5402  is closed. In contrast,  FIG.  56    includes arrows that illustrate the fluid flow within outlet pipe  4804 , inlet pipe  4814 , and flush tubing  5404  when flush valve  5402  is open.  FIGS.  55  and  56    each also include an enlarged view of Y-pipe  5500  showing how the Y-pipe may include a restricted portion  5509  between outlet pipe  4804  and flush portion  5512 , at the location of the intersection with a return section  5510  to inlet pipe  4814 , to create a venturi effect to help facilitate flushing of the system.  FIG.  57    illustrates a cross-sectional perspective view showing further details of the constriction of Y-pipe  5500 . The venturi effect generated by the constriction of the Y-pipe  5500  allows pump  4808  in the station  300  to be used to circulate fluid within the station, and to generate an aspiration to flush the station. The constriction  5509  may narrow the diameter of pipe  4804  from, for example, approximately 10 mm to approximately 8 mm, 6 mm, or 4 mm (as examples). In the examples of  FIGS.  54 - 57   , the fluid control system  909  includes a Y-pipe  5500  disposed between the flush valve  5402  and both the inlet pipe  4814  and the outlet pipe  4804  for tank  306 . 
       FIG.  58    illustrates a schematic side view of a patient-specific cartridge during installation in a tank of a station of a physical simulator device. In the example of  FIG.  58   , front support  3110  of standard frame  2500  may first be placed into position against access port  718  in sidewall  1491  of tank  306 , while base portion  3108  of frame  2500  is rotated toward bottom wall  4700  of tank  306 , until base portion  3108  contacts bottom wall  4700  and portion  3112  is in contact with sidewall  1489 , as shown in  FIG.  59   . 
       FIG.  60    shows how portion  3112  of frame  2500  can include engagement features such as magnets  6000 . As shown in  FIG.  61   , sidewall  1489  of tank  306  may be provided with corresponding engagement features  6100  for engagement with engagement features  6000  on frame  2500 , to secure cartridge  308  within tank  306 . For example,  FIG.  62    includes arrows  6200  illustrating a magnetic engagement between portion  3112  of frame  2500  and sidewall  1489  of tank  306 . Magnets  6000 , disposed on the patient-independent frame  2500  (e.g., along with magnets  6100  in the sidewall of tank  306 ) help facilitate plug-and-play installation and removal of the patient-specific cartridge  308  in the surgical simulator device  202 . 
     In the examples of  FIGS.  60 - 62   , the frame  2500  includes a base portion  3108  configured to abut a bottom surface  1402  of the tank  306  when the patient-specific cartridge  308  is installed in the tank. The frame  2500  also includes an opening  2609  configured to align with an access port  718  on a first sidewall  1491  of the tank  306 , and a rear portion  3112  including at least one engagement member (e.g., one or more of magnets  6000 ) configured to engage with a corresponding engagement member (e.g., one or more of magnets  6100 ) on an opposing second sidewall  1489  of the tank  306 . 
       FIG.  63    shows how, when magnetic engagement between portion  3112  of frame  2500  and sidewall  1489  of tank  306  holds a first side of frame  2500  in place within tank  306 , an engagement between access port  718  and front portion  3110  of frame  2500  may hold the opposing side of frame  2500  in place within tank  306 . 
     As one illustrative example of a method of using the technology disclosed herein, a method is described that includes providing a surgical simulation device  202  having a station  300  having a housing  309 , a tank  306  formed in the housing  309 , and a vascular access system  302  coupled to the housing. The method may include providing, in the tank  306 , a patient-specific cartridge  308  that includes a patient-specific model  2502  of at least a portion of a heart of a patient. The method may also include inserting an imaging device, such as an ultrasound probe  505 , through an esophageal access system  700  within the housing from an esophageal access port  304  on the housing, though a first port  714  in the tank, and into a recess  1400  in a bottom surface  1402  of the tank  306  beneath the patient-specific cartridge  308 . The method may also include inserting a surgical element (e.g., a guidewire and/or one or more cardiac interventional devices) from a vascular access port  310  of the vascular access system  302 , through a main lumen  1700  of the vascular access system, and into a portion of the patient-specific model  2502  via a second port  718  in the tank  306 . The method may also include, prior to providing the patient-specific cartridge  308  in the tank  306 , coupling first, second, and third interfacing portions  3100 ,  3103 , and  3102  of the patient-specific model  2502  to corresponding first, second, and third openings  2609 ,  2611 , and  2613  in a frame  2500  of the patient-specific cartridge  308 . The method may also include circulating a blood simulation fluid  307  through the tank  306  and at least portions of the patient-specific model  2502  (e.g., using fluid control system  909 ). The method may also include heating the blood simulation fluid  307  with a heater  4900  in the station  300 . The method may also include, prior to heating the blood simulation fluid  307  with the heater  4900  in the station  300 , preheating the blood simulation fluid  307  with an accessory heater (e.g., accessory heater  5100  or accessory heater  5300 ) configured to attach to at least one sidewall  5110  of the station  300 . The method may also include obtaining fluoroscopy images of the patient-specific cartridge  308  using x-ray absorbent material in or one the patient-specific model  2502 . 
     While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any inventions or of what may be claimed, but rather as descriptions of features specific to particular implementations of particular inventions. Certain features that are described in this specification in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable sub-combination. Moreover, although features may be described above in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a sub-combination or variation of a sub-combination. 
     Similarly, while operations may be described herein in a particular order, this should not be understood as requiring that such operations be performed in the particular order or in sequential order, or that all illustrated operations be performed, to achieve desirable results. 
     Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described components and systems can generally be integrated together in a single product or packaged into multiple products. 
     Implementations of portions of the subject matter and the operations described in this specification can be implemented in digital electronic circuitry, or in computer software embodied on a tangible medium, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them. Implementations of portions of the subject matter described in this specification can be implemented as one or more computer programs embodied on a tangible medium, i.e., one or more modules of computer program instructions, encoded on one or more computer storage media for execution by, or to control the operation of, a data processing apparatus. A computer storage medium can be, or be included in, a computer-readable storage device, a computer-readable storage substrate, a random or serial access memory array or device, or a combination of one or more of them. The computer storage medium can also be, or be included in, one or more separate components or media (e.g., multiple CDs, disks, or other storage devices). The computer storage medium may be tangible and non-transitory. 
     References to “or” may be construed as inclusive so that any terms described using “or” may indicate any of a single, more than one, and all of the described terms. The labels “first,” “second,” “third,” and so forth are not necessarily meant to indicate an ordering and are generally used merely to distinguish between like or similar items or elements. 
     Various modifications to the implementations described in this disclosure may be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other implementations without departing from the spirit or scope of this disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but are to be accorded the widest scope consistent with this disclosure, the principles and the novel features disclosed herein.