Patient-specific cardiovascular simulation device

A surgical simulation device is disclosed that allows a structural heart disease (SHD) team, including a surgeon and an imaging specialist to perform a simulated cardiac intervention procedure using a patient-specific model that replicates biomechanical and echogenic properties of a specific patient to be operated on. The surgical simulation device can include a station with a tank for receiving a patient-specific cartridge with the patient-specific model. The device can also include an esophageal access system in the station and a vascular access system that couples to an access port of the station.

TECHNICAL FIELD

This disclosure is directed simulation devices, and more particularly, to patient-specific 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

A simulation device is disclosed that mimics cardiovascular anatomical structures for training and planning interventional cardiology procedures. The simulation device can include a frame and a multi-material patient-specific cardiac model with accurate biomechanical properties and variable echogenic materials. The variable echogenic materials may be visible on ultrasound imaging, with visual aspects close to those of biological tissues.

According to some aspects of the disclosure, a surgical simulation device is disclosed that includes a patient-specific cartridge that includes a patient-specific model of at least a portion of a heart of a patient, the patient-specific model including at least a portion configured to mimic an anatomical shape and a mechanical behavior of the portion of the heart of the patient; a station having a housing; a tank formed in the housing and configured to receive the patient-specific cartridge; an esophageal access system extending within the housing between an esophageal access port on the housing and a first port in the tank; and a vascular access system comprising a first end with a vascular access port and a second end configured to be fluidly coupled to a second port in the tank.

According to other aspects of the disclosure, a patient-specific cartridge for a surgical simulator device is provided, the patient-specific cartridge including a patient-independent frame having first, second, and third openings; and a patient-specific cardiac model. The patient-specific cardiac model includes a right atrium; a left atrium and a septum having mechanical and anatomical shape properties that correspond to the mechanical and anatomical shape properties of the left atrium and the septum of a patient; a superior vena cava interfacing portion that deviates from the anatomical shape of the superior vena cava of the patient and extends between the right atrium and the first opening in the patient-independent frame; an inferior vena cava interfacing portion that deviates from the anatomical shape of the inferior vena cava of the patient and extends between the right atrium and the second opening in the patient-independent frame; and an upper pulmonary vein interfacing portion that deviates from the anatomical shape of the pulmonary vein of the patient and extends between the left atrium and the third opening in the patient-independent frame.

According to other aspects of the disclosure, a surgical simulation device is provided that includes a station having a housing; a tank formed in the housing and configured to receive a patient-specific cartridge that includes a patient-specific model of at least a portion of a heart of a patient, wherein the tank comprises a bottom wall having a first surface that forms a bottom surface of the tank, and an opposing second surface; an esophageal access system extending within the housing between an esophageal access port on the housing and a first port in the tank; a vascular access system including a first end with a vascular access port and a second end configured to be fluidly coupled to a second port in the tank; and a spinal shadow simulation card disposed within the housing adjacent the opposing second surface of the bottom wall of the tank.

According to other aspects of the disclosure, a method is provided that includes providing a surgical simulation device having a station having a housing, a tank formed in the housing, and a vascular access system coupled to the housing; providing, in the tank, a patient-specific cartridge that includes a patient-specific model of at least a portion of a heart of a patient; inserting an imaging device through an esophageal access system within the housing from an esophageal access port on the housing, though a first port in the tank, and into a recess in a bottom surface of the tank beneath the patient-specific cartridge; and inserting a surgical element from a vascular access port of the vascular access system, through a main lumen of the vascular access system, and into a portion of the patient-specific model via a second port in the tank.

According to other aspects of the disclosure, a surgical simulation device is provided that includes a patient-specific cartridge that replicates anatomical and acoustic features of an organ of a specific patient; a station including a tank configured to receive the patient-specific cartridge: a surgical access system coupled to the station and including a lumen extending from a surgical access port to an access port for the tank, the lumen configured to simulate a blood vessel of a generic patient; and an imaging access system extending within the station from an imaging access port to the tank, the imaging access system comprising a lumen configured to simulate an imaging access pathway within the generic patient.

According to aspects of the disclosure, the imaging access system mimics an esophagus of a generic patient, and provides access to a transesophageal echocardiography probe.

DETAILED DESCRIPTION

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 of 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.1shows 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 cava110into the right atrium101of a heart100of a patient, then into the left atrium102via a transseptal puncture through the septum112. As shown inFIG.1, these interventions can be performed to manipulate and/or address issues with the mitral valve between the left atrium102and the left ventricle104, the pulmonary vein114, and/or the left atrial appendage116(as examples).

To perform successful interventions (e.g., of the types shown inFIG.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 septum112for 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 inFIG.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 includes a patient-independent frame and a multi-material patient-specific cardiac model with realistic biomechanical properties and that is visible on ultrasound imaging with an aspect that is close to the corresponding aspect of corresponding 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.2illustrates a Cath lab200implementing a simulator system that includes a physical simulator device202(e.g., supported on a Cath lab table210), an imaging system204(e.g., a fluoroscopy system), an ultrasound system208(e.g., an ultrasound imaging system), and a display206on which images such as ultrasound and fluoroscopy images of a cartridge within a tank of the station of the physical simulator device202can be seen.

Details of the physical simulator device202are shown inFIG.3. InFIG.3, physical simulator device202is shown in superimposed over a depiction399of a human body so that the alignment between various features of the physical simulator device202and body of a patient can be seen. In particular,FIG.3shows show the physical simulator device202may include a station300having a tank306arranged to receive a patient-specific cartridge308that mimics the mechanical and acoustic features of at least portions of a heart of a particular patient.

As shown, the tank306is positioned relative to an esophageal access port304and vascular access port310, 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 device202mimics 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.3also shows how the physical simulator device202includes a vascular access system302coupled to the station300, and having a curvature that allows the vascular access system302to mimic a portion of the femoral vein, the right external and common iliac veins312, and the vena cava314leading to the right atrium of the simulated patient heart in cartridge308.

In some implementations, the combination of the cartridge308and the station300aim to achieve the functionality of all the anatomical parts needed for a Left Atrial Appendage (LAA) closure intervention. The station300and a frame of the cartridge308may represent standard anatomical parts (e.g., of a generic patient) and a patient-specific model of the cartridge308may represent the patient-specific anatomical parts.

In this example, the LAA closure intervention starts with a puncture at a port310in 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 cartridge308. The catheter enters the cartridge308, which includes the patient-specific part of the system.

To access to the LAA, the cardiologist must cross the replicate septum of the cartridge308at a specific spot for the LAA procedure, within the fossa ovalis. For example,FIG.4is a portion of a Mayo Clinic® image that illustrates a location408on the fossa ovalis400for the transseptal puncture for a LAA procedure. Other locations on the fossa ovalis400are also shows for transseptal punctures for other procedures, such as a location404for a transseptal patent foramen ovale closure, a location402for a paravalvular leak closer, a location406for a percutaneous left ventricular assist device placement, and a location410for a pulmonary vein intervention.

Cartridge308includes 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 cartridge308. 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 inFIG.3, during a simulated procedure, the cartridge308is positioned within the tank306disposed within the station300, and submerged in a fluid307(e.g., water or a blood mimicking fluid) in the tank306, so that the simulated tissue and interventional tools can be seen under ultrasound imaging (as described in further detail hereinafter). Station300may also include fluid control systems for circulating, flushing, filtering, heating, and/or otherwise manipulating the blood mimicking fluid307, as described in further detail hereinafter.

FIGS.5A and5Bshow additional views of features of the physical simulator device202during a simulated LAA procedure (e.g., in a simulated fluoroscopic view representing the appearance of aspects of the system under x-ray imaging). For example, inFIG.5A, an ultrasound probe505(e.g., a transesophageal echocardiographic (TEE) ultrasound probe), a guidewire507, and operational components501(e.g., pumps for moving fluid through the physical simulator device202) can be seen. In this example, the ultrasound device505has been inserted, via an esophageal access system within the station, under the cartridge308in the tank306. Guidewire507has been inserted via vascular access device302, through into a portion of the patient-specific cartridge308.

InFIG.5Bcartridge308can be seen with a delivery device for an LAA closure device502having been passed through a transseptal puncture511in a simulated septum112′ to close the simulated LAA116′. A position marker500on the delivery device can also be seen.

FIG.6illustrates a perspective view of the physical simulator device202, according to aspects of the disclosure. In the example ofFIG.6, housing309of station300can be seen coupled to a surgical access device such as vascular access system302. In this example, the vascular access port310at the proximal end of the vascular access system302can be seen. Tank306in the housing309of station300can also be seen.

The station300and/or vascular access system302may be arranged to represent certain standard (i.e., non-patient specific) anatomical parts involved in a simulated intervention. The primary functions of the station300are to hold the cartridge308(e.g., including the patient-specific cardiac model) in an anatomically relevant position, circulate fluid through the cartridge308to simulate blood flow, and provide anatomically realistic vascular and esophageal access.

The simulated vascular access provided by vascular access system302simulates the right femoral vein, iliac vein, and inferior vena cava access. The simulated esophageal access can be disposed within housing309and 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 components501ofFIG.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 station300of fluid post procedure.

The station300and vascular access device302are 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 inFIG.3. Accordingly and as described in further detail hereinafter, the station300includes a main housing309surrounding the pump (e.g., pump501), the tank306(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 device202may be implemented with as a surgical simulation device that includes a patient-specific cartridge308that 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 station300including a tank306configured to receive the patient-specific cartridge308, a surgical access system302coupled to the station300and including a lumen1700extending from a surgical access port310to an access port718for the tank306, the lumen1700configured to simulate a blood vessel of a generic patient and an imaging access system700extending within the station300from an imaging access port304to the tank306, the imaging access system comprising a lumen900configured to simulate an imaging access pathway within the generic patient.

FIG.7illustrates a cross-sectional side view of a station300with an imaging access system implemented as an esophageal access system700. In the example ofFIG.7, esophageal access system700extends, within housing309, from a proximal end710at the imaging access port304on housing309to a distal end714within the housing. As shown, the distal end714forms a port in the tank306that allows an imaging device, such as a TEE device, to be extended into the tank from imaging access port304. A proximal membrane711at imaging access port304, and distal membrane712at an interface between a first pipe member702and a second pipe member704of the esophageal access system700may be included.FIG.7also shows how the housing309of station300may include an access port706to which vascular access system302can be attached, and which includes an additional port718into tank306, opposite to the port formed at the distal end714of the esophageal access system700. Port718may be arranged to interface with a superior vena cava (SVC) interface on the patient-specific cartridge308, as described in further detail hereinafter.

For ergonomic and sealing reasons, the replicated esophageal access system/TEE approach system700may not be fully anatomical in terms of shape, size and angulation of a patient's esophagus708. Instead, a standardized approach for the TEE approach system700may be used that allows a clinician to place a TEE probe505in a position in the station300that 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.8illustrates station300, in side-view alignment with, and superimposed on a representation of a generic patient's esophagus708, showing how the imaging access port304is generally aligned with the generic patient's mouth800, and pipe sections702and704approximate the pathway of the generic patient's esophagus708and lead to the bottom of tank306at a position that would be beneath the patient's heart802. In this way, the simulated esophageal access system700ofFIG.7may provide good ergonomics without leaks and without impacting the realism of the navigation of the imaging device.

FIGS.9and10show certain design parameters selected for the esophageal access system700that provide the realistic navigation with improved ergonomics. Such parameters include first and second bends904and906having radii of curvature (e.g., 67 mm) at the respective proximal and distal ends of the replicated esophageal channel900, the length of a conduit903between the proximal and distal bends (e.g., 125 mm), and the angle formed between the conduit903and 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. InFIGS.9and10, portions of the fluid flow control system909of station300are also shown, as will be described in further detail hereinafter.

FIG.11shows another view of the esophageal access system700in the station300, with a cartridge308installed in the tank306and coupled, at interface port718, to vascular access port706within the housing.FIG.12shows a cross section of the primary conduit903of the replicated esophageal channel900with illustrative, non-limiting dimensions.

As illustrated inFIGS.7-11, the esophageal access system700may include first and second pipe sections702and704within the housing309, the first pipe section702extending from the esophageal access port304on the housing309to the second pipe section704, and the second pipe section704extending from the first pipe section702to a first port (at distal end714) in the tank306. The first pipe section702may include a first bend904at a proximal end, and a substantially straight conduit903extending from the first bend904to the second pipe section704. The second pipe section704includes a second bend906. The second bend906may form an angle of between one hundred thirty degrees and one hundred seventy degrees between the substantially straight conduit903and a bottom surface (see, e.g., bottom surface1402ofFIG.14) of the tank. The esophageal access system700may also include a first membrane711at the esophageal access port304and a second membrane712at an interface between the first pipe section702and the second pipe section704.

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 system700is 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 system700may combine two interchangeable membranes (e.g., latex membranes) located on the way to the tank306(e.g., a proximal membrane711at the top of the station300at the proximal end of the esophageal access system700, and a distal membrane712just before the tank), as illustrated inFIG.13. These two membranes711and712may be changed easily in order to be compatible with all probes (e.g., different brands, shrinking sizes, etc.)

FIG.14shows a top-down view of the station tank306, with the patient-specific cardiac model removed. As shown inFIG.14, a recess1400is formed in the bottom surface1402of tank306, into which the TEE probe can extend from the tank port at the distal end714of the esophageal access system700. In the example ofFIG.14, the recess1400is wider than the probe505allowing the clinician an ability to adjust the probe position within the tank306in a realistic manner with realistic movement constraints.

FIG.14also shows how access port718may be formed on a sidewall1491of tank306. As shown, additional access ports such as access ports1404and1408can be provided on an opposing sidewall1489of tank306. Access port718may be arranged to interface with a simulated superior vena cava interface on patient-specific cartridge308. Access port1404may be arranged to interface with a simulated inferior vena cava interface on patient-specific cartridge308. Access port1408may be arranged to interface with a simulated upper pulmonary vein interface on patient-specific cartridge308.

FIG.14also shows how one or more fluidic openings such as fluidic openings1406,1410, and1412may be provided in tank306, to allow flow of blood simulation fluid307around a patient-specific cartridge308that is mounted in tank306(e.g., in addition to and/or in place of fluid307flow into and/or out of the patient-specific structures of cartridge308via access ports1404,1408, and718). Fluidic openings1406,1410, and1412may be fluidically coupled to fluid control system909(see, e.g.,FIGS.9and10), as described in further detail hereinafter, and may be located at different positions from those shown inFIG.14in some implementations. Access ports1404,1408, and718may also, or alternatively, be fluidically coupled to fluid control system909(see, e.g.,FIGS.9and10), as described in further detail hereinafter.

FIGS.15A and15Bshow perspective exploded and perspective views, respectively, of the vascular access system302that couples to and extends away from the station300. The vascular access system302replicates 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 inFIG.15, the proximal end1500(e.g., the end configured to be proximal to the clinician during a simulated procedure) of the vascular access system302includes sealing membrane1502(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 inFIG.15B, the vascular access port310formed at proximal end1500is wide enough to allow for the use of an introducer, which may be needed for certain difficult to catheterize patients. As can be seen inFIG.15A, the sealing membrane1502is replaceable by removal of a seal cap1504that covers the proximal end1500of the vascular access system302. The sealing membrane1502itself can include several alignment holes1506that are aligned with posts1508extending upwards from a portion of the proximal end of the vascular access system to ensure proper seal placement.

As shown inFIGS.15A and15B, the bottom side of the vascular access system302includes a number of flanges1517extending downwards from the main shaft1510to support the vasculature access system at a height over a Cath lab patient table (see, e.g., table210ofFIG.2) that would be anatomically appropriate for an average patient.

The vascular access system302can 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 shaft1510includes an interior lumen (not visible inFIGS.15A and15B) of the vascular access system302, which can have a substantially constant diameter for the majority, or in some implementations, the entirety of the length of the lumen.

FIGS.16A and16Bshow a side view and top view, respectively, of the vascular access system302. As can be seen inFIGS.15and16B, the vascular access system302(e.g., the main shaft1510and internal lumen) has a curvature (e.g., including a first or proximal curve1611and a second or distal curve1613) that substantially replicates the path of the right femoral vein, iliac vein and inferior vena cava to the right atrium.

FIG.17shows a top down cutaway view of the vascular access system302coupled to the housing309of the station300at access port706. The access system302can be screwed onto the access port706of the housing309, providing fluidic access between the internal lumen1700within main shaft1510to the interior of the tank306. When a patient-specific cartridge308with a patient-specific cardiac model is installed in the tank306(as shown inFIG.17), the coupling between vascular access system302and access port706of housing309provides fluidic coupling between internal lumen1700and a portion of the patient-specific model that simulates a portion of the right atrium of the patient.

FIG.18shows an enlarged view of the access port706, formed in the housing309, for connection between the vascular access system302and a cartridge308installed in the tank306of the station300. As shown inFIG.18, the access port706may be implemented as a dual-lumen pipe1800within housing309, with a central lumen1805allowing a catheter access to a cardiac model within the station tank306and to allow fluid to flow into the vascular access system302(e.g., into main lumen1700). An outer toroidal chamber1802may be provided that surrounds the central lumen1805and is fluidically coupled to the central lumen1805through an array of through holes1804.

The holes1804(shown in cutaway detail inFIG.19) may be angled away from the tank306of station300at, for example, 60 degrees from the horizontal, though the angle can be between 50 and 75 degrees in other implementations. This angling of the holes1804away from tank306(e.g., opposite to the direction in which surgical instruments moved toward the tank during insertion) helps ensure that a catheter, guidewire, or other surgical instrument being inserted into the tank via central lumen1805does not catch on the holes. The holes1804, 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 chamber1802is fluidically coupled by a return fluid channel1702to the tank306. As such, if too much fluid pressure builds up in the vascular access system302or in the replicated right atrium, the fluid can escape through the holes1804and be rerouted back to the tank306. In some implementations, the hole array only occupies the top half of the wall of the central lumen1805. In other implementations, more or less of the wall surface of the central lumen1805is occupied by through holes.

FIGS.20and21show two different perspective views of the housing309of station300, showing the tank306at different angles. Also seen inFIGS.20and21is an opening2002in housing309for the proximal end710of the esophageal access system700.FIG.20shows interface port718connecting to the passageway (e.g., central lumen1805of access port706) out of the tank306to the vascular access system302.

As illustrated inFIGS.20and21, the interior of the tank306may be coated with acoustic shielding2006. A perspective view of the acoustic shielding2006is also shown inFIG.22. The acoustic shielding2006may be constructed from ethylene propylene diene monomer (EDPM) rubber, though other polymer coatings with similar acoustic properties could be used instead. The acoustic shield2006helps prevent the walls of the tank306from 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 tank306may be coated with linings of low ultrasonic reflection yet highly absorbent to ultrasound (EDPM is one such material). For example, acoustic shielding2006may provide absorption of acoustic energy in the frequency range of 1 MHz<F<10 MHz (e.g., the frequency range for medical ultrasound imaging), or 4 MHz<F<8 MHz (e.g., the frequency range for TEE: Trans Esophageal Echography).FIG.23shows two ultrasound images, including a first image2300obtained with a tank that has the acoustic shielding2006, and a second image2302obtained with a tank that does not have acoustic shielding, to show the impact of the shielding.

FIG.24shows a cutaway view of the tank306with the acoustic shielding2006. Also visible inFIG.24are the distal end714of the esophageal access system700, the recess1400in which a TEE probe can positioned after passing through lumen900, the access port706for coupling to the vascular access system302, and a fluid channel2402for introducing fluid into the simulated pulmonary vein of the cardiac model (not shown inFIG.24). As shown, the recess1400may be a recess in a bottom wall2400of tank306.

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 cartridge308with a patient-specific cardiac model that has the advantages of being arranged for mounting to interface port718in tank306of station300, 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.25illustrates an example of a patients-specific cartridge308that includes a frame2500and a cardiac model2502. Of the cardiac model2502, one or more, and in some implementations, all of the following components are patient specific: the replicated septum112′, the replicated fossa ovalis400′ of the septum (e.g., both the position and biomechanics of the replicated fossa ovalis400′ 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 vein2505and the spur (also referred to as a ridge) separating the left pulmonary vein2505from the left atrium2504, the replicated Left Atrial Appendage116′ (e.g., the position of the LAA116and its trabeculae, including both position and biomechanics can be patient specific), and the replicated mitral ring2503(e.g., the position of the replicated mitral ring may be patient specific).

In some implementations, the cardiac model2502may include either patient-specific or standardized portions for a replicated portion2506of the right atrium and non-patient specific portions of the left atrium2504.

A method for fabricating a patient-specific physical cardiac simulation device such as patient-specific cartridge308may 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 (patient-independent) 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 ofFIG.25, the frame2500holds a cardiac model2502that includes a portion2506corresponding to a patient's right atrium, a portion2504corresponding to the patient's left atrium, a portion116′ corresponding to the patient's left atrial appendage116extending 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 vein2505(positioned behind the left atrial appendage). A portion400′ corresponding to the patient-specific fossa ovalis separates the right atrium from the left atrium. In some implementations, the portion2506corresponding to the right atrium need not be patient specific and may have a standard shape and material composition.

FIGS.26A and26Billustrate perspective and top views, respectively, of another example cardiac model2502incorporated into a frame2500, according to another implementation. In contrast to the model shown inFIG.25, the cardiac model2502shown inFIGS.26A and26Bincludes a window2600in an upper facing-portion of the replicated right atrium2506. The window2600, formed by an absence of material (for example), provides both visual access to the replicated right atrium2506during a planning/practice procedure, reduces the time, complexity, materials, and cost of manufacturing the cardiac model2502, as well as improves the ultrasound aspect of the device (e.g., by avoiding unrealistic ultrasound effects generated by a top wall of the right atrium). In addition, the model2502shown inFIGS.26A and26Bincludes a replicated aortic valve annulus2602not seen inFIG.25. InFIG.26B, the replicated fossa ovalis400′ can be seen clearly through the window2600formed in the right atrium model portion2506, avoiding the need for fluoroscopy during the practice/planning procedure. Finally, the window2600provides an avenue for air bubbles to escape the replicated right atrium2506that might introduce artifacts in an ultrasound image.

The frame2500in all ofFIGS.25,26A, and26Bis 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 model2502. The frame2500also has standard dimensions used for all patients, so that the cartridge308can be securely positioned within the tank306of the station300and such that the fluidic channels of fluid control system909of the station mate with the model fluid ports connected to the right atrium and pulmonary vein portions2506and2505of the model2502to ensure proper fluid flow through the model. For example, as shown inFIG.26A, frame2500may include openings2609,2611, and2613corresponding, respectively, to the simulated superior vena cava interface, the inferior vena cava interface, and the upper pulmonary vein interface of the patient-specific model2502, and respectively, to the access ports718,1404, and1408in tank306.

In some implementations, the standard frame2500includes the right atrium portion2506of the cardiac model2502, other than the septum112′ and fossa ovalis400′ separating the right atrium from the left atrium portions of the model. In general, the artificial tissues may range in thickness from between about 0.5 cm to about 2.5 cm.

To help provide biomimetic mechanics of the replicated fossa ovalis400′, 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 ovalis400′ during procedures. For example,FIG.27shows two images2700A and2700B, each with a view of an example model fossa ovalis400′, included in the cardiac model2502. Image2700A shows a view of the external surface2702of the model fossa ovalis400′. Image2700B shows a view of the interior structure of the model fossa ovalis400′. In overview, the model fossa ovalis400′ can be constructed from, for example, three structural layers, including two outer layers (e.g., one facing the right atrium and one facing the left atrium), and an inner reinforced layer2707. The inner reinforced layer2707includes an array of honeycomb structures.

The thickness and other material and/or mechanical properties of the patient-specific model2502may 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 model2502is 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 ovalis400′ for patient-specific model2502, the simulated fossa ovalis may be provided with a superior-inferior diameter of, for example, 20.8±16.2 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 septum112′ may be thickest above the fossa ovalis400′ adjacent to superior vena cava entrance2609(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 ovalis400′ 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 toward s the center (fossa ovalis), progressively increasing (e.g., in a direction opposite the radial direction R indicated inFIG.27) 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=c10(Ī1−3)+c01(Ī2−3)+c20(Ī1−3)2+c11(Ī1−3)(Ī2−3)+c02(Ī1−3)2(1)
where I1and I2are invariants of strain, and cijare material constants such as the constants provided in Table 1 below.

The mechanical features of the simulated septum112′ 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 septum112′ allow the patient-specific cartridge308to mimic a patient's actual transseptal tenting and puncture for clinicians training and/or patient-specific rehearsal. The mechanical features of the simulated septum112′ may be arranged to be nearly isotropic and hyperelastic. Accordingly, in some implementations, the simulated fossa ovalis400′ of patient-specific model2502may be isotropic and hyperelastic with a flexibility gradient of decreasing flexibility with increasing radial distance from the center of the fossa ovalis.

FIG.27also includes a diagram2700C showing more detailed geometry of the honeycombs2709that may be included in inner reinforced layer2707, 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 septum112′ and fossa ovalis400′ of the patient-specific model. For example, each honeycomb2709can be hexagonal in shape, with a diameter D ranging from around 5.0 mm to about 6.0 mm. The honeycomb can be fabricated, for example, from Acrylonitrile butadiene styrene (ABS). 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 to about 0.4 (e.g., 0.36) mm. The honeycomb structure can be filled, for example with Agilus polyjet material having a Young's Modulus of between about 0.6-5 MPa. In contrast, the ABS that forms the honeycomb can have a Young's Modulus of between about 1-2 GPa. The inner and outer layers of the model fossa ovalis400′ can also be formed form Agilus, and have a thickness of between about 0.30 mm and 0.35 mm (e.g., 0.32). Together the model fossa ovalis400′ may be about 1 mm thick, though thickness may be varied based on the specific anatomy of the patient.

The remaining patient-specific portions of the cardiac model2502can 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. patent application Ser. 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.

For example, manufacturing the patient-specific portions of patient-specific model2502may include obtaining medical image data of an organ (e.g., the patient's heart) within a specific patient. The medical image data may then be processed to generate one or more data files including a volumetric model of the organ. Generating the data file(s) may include receiving one or more material data files specifying a configuration of one or more materials to be deposited by an additive manufacturing system. The patient-specific model may then be generated by dispensing at least one first material having lower acoustic impedance properties and a second material having higher acoustic impedance properties.

The medical image data of the organ may be obtained using common medical imaging modalities such as X-ray radiography, X-ray rotational angiography, MRI, CT scanning, ultrasound imaging (2D or 3D), or nuclear medicine functional imaging techniques such as positron emission tomography and single-photon emission computed tomography. The medical image data may be obtained for an organ within a specific patient or for pan of a larger organ. For example, the organ may be a heart, a portion of a heart, or an artery. The medical image data may also include data associated with organs surrounding or located in close proximity to the organ being imaged such as bones, joints, fatty tissue, glands, or membranes which may exert mechanical feedback on the organ to be replicated.

The medical image data may be processed to generate a volumetric model of the specific organ to be replicated as the patient-specific model2502. The volumetric model may be generated by converting the medical image data into a three dimensional data model describing the anatomic characteristics of the organ to be replicated. The anatomic characteristics may include various linear dimensions, volume dimensions, thicknesses, as well as other characteristics of the organ being replicated, such as tissue echogenicity. Such characteristics can be derived directly from the medical imaging data collected (e.g., from ultrasound images), or indirectly by reference to one or more databases or other electronic data sources of anatomical knowledge that stores reference information about representative tissue characteristics of various tissues in the body. The volumetric model includes a three dimensional set of nodes which define a plurality of elementary volumetric elements or voxels partitioning a space region (e.g., the space encompassed by the organ or portions of the organ) modeled by the volumetric model. The elementary volumetric elements may be defined as shapes of a tetrahedron, a pyramid, a triangular prism, a hexahedron, a sphere, or an ovoid. The volumetric model may be generated from a three dimensional surface mesh of the organ to be replicated which captured in the medical image data. In some implementations, the volumetric model may be generated by performing volumetric model generation on the surface mesh. In some implementations, the volumetric model is generated by performing finite-element volumetric model generation on the medical image data. In some implementations, the volumetric model is further processed to generate a deformed volumetric model of the organ to be replicated. In these implementations, the deformed volumetric model replicates the loads and constraints imposed on the in vivo organ tissue of a specific patient by one or more organ tissues surrounding the specific patient's in vivo organ tissue.

Defining the three dimensional set of nodes and the elementary volumetric elements or voxels associated with the imaged organ allows a plurality of materials to be assigned to each voxel so that the additive manufacturing system may form the patient-specific model2502such that the echogenic properties of the in vivo organ tissue at one or more locations are accurately replicated in the corresponding locations of the patient-specific model2502. The assigned materials may include materials of differing acoustic impedance values, such as higher acoustic impedance materials, lower acoustic impedance material, or mixtures or suspensions of materials having different acoustic impedances.

Material assignment is performed using a cost function to minimize the error between the desired echogenic properties (determined based on the medical image data or from electronic databases or data sources storing representative tissue characteristic data) and the resulting echogenic properties of the combination of one or more of the materials selected for deposition in a location corresponding to a given voxel or cluster of voxels of the volumetric model. In some embodiments, the cost function may include additional cost functions, for example a cost function to minimize the error associated with the elastic material properties or other mechanical material properties of the organ being replicated. In these embodiments, material assignment may be achieved by solving the cost function using a joint search to minimize the sum of the errors between the mechanical material properties and the echogenicity material properties. In some implementations, weights may be applied to the respective constituent cost functions based on the desired application. For example, it may be desirable to apply a higher weight to the cost function associated with mechanical material properties when accurately simulating echogenicity in the patient-specific model2502is less important. Alternatively, it may be important to weight the cost function associated with echogenic material properties higher in situations where it is critical to accurately simulate echogenicity in the patient-specific model2502. After performing a joint search as described above, a final volumetric model may be generated.

In some implementations, as an alternative to a joint search method, a predetermined number of best fitting echogenic (acoustic) property models could be evaluated using a mechanical property cost function to select an overall best fitting model. Additionally, or alternatively, a predetermined number of best fitting mechanical property models may be evaluated using an echogenicity cost function to identify an overall best fitting model. In some implementations, the cost function may include constraints to prevent aspects of the volumetric model from being assigned specific materials. For example, a constraint may be implemented to require lower acoustic impedance materials formed from sacrificial material to be fully encapsulated within one or more higher acoustic impedance materials.

The object materials to be assigned to each voxel that were determined as a result of applying the cost function(s) may be selected from a database of object materials. In some implementations, a particular material may be selected based on the results of minimizing a cost function for a given region (e.g., a cluster) or plurality of elementary volumetric elements of the volumetric model.

In some implementations, processing the medical image data includes converting the medical image data from a data or file format that is specific to the particular medical imaging modality used to obtain the medical image data into a data or file format that is compatible with an additive manufacturing system. For example, the medical image data may be processed and converted into one or more STL data files or other additive manufacturing system compatible file format. The STL file format may be utilized by the additive manufacturing system to generate a 3D patient-specific model2502based on the volumetric model included in the one or more data files.

One or more material data files may specify a configuration of one or more materials to be deposited by an additive manufacturing system. The one or more material data files may define an arrangement or configuration of a plurality of echogenic and non-echogenic materials (or higher acoustic impedance and lower acoustic impedance materials) to be deposited by the additive manufacturing system based on the processed image data. For example, based on the plurality of materials assigned to each voxel of the volumetric model included in the one or more material data files, the additive manufacturing system may determine the arrangement of one or more materials to be deposited in one or more layers to form the patient-specific model2502.

The additive manufacturing system may form the patient-specific model2502by dispensing at least one material having lower acoustic impedance properties and a second material having higher acoustic impedance properties. The additive manufacturing system dispenses the plurality of materials to form the patient-specific model2502. The plurality of materials includes at least one lower acoustic impedance material and a higher acoustic impedance material. The two materials may be dispensed simultaneously as a suspension of the higher acoustic impedance material within the lower acoustic impedance material, or as separate depositions of higher acoustic impedance material and lower acoustic impedance materials. Based on the configuration of materials assigned to each voxel of the volumetric model included in the one or more material data files, the additive manufacturing system dispenses the appropriate material determined for a given elementary volumetric element defined in the volumetric model of the organ to be replicated. For example, the additive manufacturing system dispenses amounts of at least one hypo-echogenic material at locations in the patient-specific model2502which map or correspond to the same locations in the volumetric model that were determined to be less echogenic areas or regions based on the medical image data. Similarly, hyper-echogenic materials (e.g., a suspension with a higher density of high acoustic impedance material) may be dispensed by the additive manufacturing system at locations in the patient-specific model2502which correspond to the same locations in the volumetric model that were determined to be more echogenic.

There need not be a one-to-one correspondence between a voxel and a given material deposition. A voxel is a logical construct which can be processed by an additive manufacturing device to determine an appropriate set of independent material depositions. For example, some volumetric models may be generated with lower resolution than a print-resolution of a 3D printer used to print the patient-specific model2502. In such situations, the 3D printer may make multiple deposits of material to generate a single voxel. For example, in some implementations, each voxel may correspond to a 3×3×3, 4×4×4, 5×5×5, or other sized cuboid of material depositions. In other implementations, voxels may translate into ovoid or other shaped depositions, rather than cuboid depositions. The 3D printer used to fabricate the patient-specific model2502may translate an echogenicity value assigned to each voxel to an appropriate pattern of material depositions within a given a corresponding cuboid or ovoid deposition. In other implementations, each voxel corresponds to a single material deposition, which may have a spherical, ovoid, rectangular or other regular or irregular shape depending on the equipment used to make the deposition. The at least one material having lower acoustic impedance properties and the second material having higher acoustic impedance properties may be dispensed by the additive manufacturing system using casting, 3D printing, mechanical linkages of disparate materials and material deposition manufacturing. A variety of additive manufacturing processes may be utilized by the additive manufacturing system to form the patient-specific model2502including binder jetting, directed energy deposition, material jetting, power bed fusion, fused deposition modeling, laser sintering, stereolithography, photopolymerization, and continuous liquid interface production. In some implementations, 3D printers using PolyJet Matrix™ technology (Stratasys, Ltd., Eden Prairie, MN) may be used to simultaneously dispense a plurality of materials having different elastic and acoustic impedance properties to form an patient-specific model2502with varying elastic and echogenic properties at one or more locations. In some implementations, the at least one material having higher acoustic impedance properties includes a polymerized material, such as PolyJet material having a polymerized density of 1.18-1.21 g/cm3. In some implementations, the lower acoustic impedance includes a hydrogel with acoustic properties similar to water. In some implementations, the lower acoustic impedance material includes a non-polymerized material such as water, a gel, an ion, or a bio-molecule.

In the example ofFIG.27, the patient-specific model2502includes a fossa ovalis400′ 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).

FIG.28shows three images2800A,2800B, and2800C of an example cardiac model cartridge308under ultrasound, demonstrating the biomimetic ultrasound response of the model. In particular, images2800A and2800B show the model septum before and after pressure from a puncturing instrument is applied to the septum (causing the tenting in image2800B). Image2800C shows the model LAA before and after occlusion. In various scenarios, the surgical simulation device202may be used by providing a surgical simulation device202having a station300having a housing309, a tank306formed in the housing309, and a vascular access system302coupled to the housing309, providing, in the tank306, a patient-specific cartridge308that includes a patient-specific model2502of at least a portion of a heart of a patient, inserting an imaging device (e.g., TEE probe505) through an esophageal access system700within the housing309from an esophageal access port304on the housing309, though a first port (at end714) in the tank306, and into a recess1400in a bottom surface1402of the tank306beneath the patient-specific cartridge308, and inserting a surgical element (e.g., a guidewire, a tool, etc.) from a vascular access port310of the vascular access system302, through a main lumen1700of the vascular access system302, and into a portion of the patient-specific model2502via a second port718in the tank306. The imaging device may then be operated to capture images such as ultrasound images2800A,2800B, or2800C, to aid in manipulating the surgical element to, through, around, or within various portions of the patient-specific model.

FIG.29shows an example entry to the replicated left atrial appendage116′ to be occluded during example procedures contemplated to be carried out using the station300and cartridges308disclosed herein. As can be seen inFIG.29, the interior surface2900of replicated left atrial appendage116′ may include a micropattern of small depressions2902. The depressions2902shown inFIG.29are circular in shape, though other regular or irregular geometric shapes may also be used. Each depression2902can 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 appendage116′.

FIG.30illustrates 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.30shows a patient's fossa ovalis3000, 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 ovalis400′ described above in connection withFIG.27.

As described above in connection with, for example,FIGS.26A and26B, patient-specific cartridge308may include a patient-specific model2502coupled to a frame2500. In some implementations, the frame2500is a patient-independent frame that can carry various different patient-specific models.FIG.31illustrates a perspective view of a patient-specific cartridge having a patient-independent frame, according to aspects of the disclosure. As shown inFIG.31, patient-specific model2502may include a patient-specific portion (e.g., including the simulated right atrium2506, the simulated left atrium2504, the simulated aortic annulus2602, and the left atrial appendage116′) in which the shape, mechanical properties, acoustic properties, and/or other properties correspond to the same properties of a specific patient. The patient-specific model2502may also include interfacing portions such as interfacing portions3100,3102, and3103that may deviate, in shape, size, orientation, and/or mechanical properties, from the corresponding properties of the patient, in order to interface with standard frame2500. As shown inFIG.31, patient-independent frame2500may include a base portion3108, a proximal portion3112, and a distal support3110surrounding opening2609(e.g., corresponding to a superior vena cava interface for patient-specific cartridge308). As shown, interfacing portion3100extends between the patient-specific portion of patient-specific model2502and opening2609of frame2500. Interfacing portions3100,3102, and3103may be integrally formed portion of a contiguous patient-specific model2502, though they may deviate from the patient's anatomical shape.

FIG.32illustrates a perspective view of the patient-independent frame2500ofFIG.31, with the patient-specific model removed. As shown inFIG.32, proximal portion3112may include two additional openings2611and2613. As shown inFIG.32, a curved support structure3207may also extend from proximal portion3112for supporting and/or orienting patient-specific model2502on the frame.

FIG.33illustrates a perspective view of a patient-specific cartridge308having a patient-specific model2502coupled to a patient-independent frame2500in an orientation in which an upper pulmonary vein interface portion3102of patient-specific model2502extends between the patient-specific portion of patient-specific model2502and opening2613in frame2500. Because interfacing portions3100,3102, and3103are allowed to deviate from the patient-specific shape of the patient-specific portion, each patient-specific model2502is arranged to include features that anatomically, mechanically, and/or acoustically correspond to a particular patient, while coupling to the same patient-independent frame2500, which reduces cost, and increases ease of use of the simulator device202.

For example,FIG.34illustrates a patient-specific cartridge308having another patient-specific model2502coupled to the patient-independent frame2500. As shown inFIG.34, the patient-specific portion of patient-specific model2502is different from that ofFIG.33, resulting in interfacing portions3100′,3102′, and3103′ having different shapes from portions3100,3102, and3103ofFIG.33that allow interfacing to the same standard openings2609,2611, and2613of the same standard model2500.

FIG.35illustrates a patient-specific model2502, emphasizing the patient-specific portion(s) of the model, which may include the simulated right atrium2506, aorta2602, left atrium2504, and left atrial appendage116′.FIG.36illustrates three different patient-specific models2502A,2502B, and2502C, each having different patient-specific features (e.g., patient-specific right atria2506, aortas2602, left atria2504, and left atrial appendages116′) that match the anatomical, mechanical, and acoustic characteristics of the corresponding features of a particular patient, and each having different interfacing portions3100,3102, and3103that allow the different patient-specific features to interface with the same standard frame2500. As shown, the three different patient-specific models2502A,2502B, and2502C can be coupled to a patient-independent frame2500to form three different patient-specific cartridges308A,308B, and308C.

For example,FIG.37shows how a patient-specific model2502can have an integrally formed upper pulmonary vein interfacing (coupling) portion3102that deviates from the patient's anatomical form and extends between the patient-specific portion and opening2613. Arrow3700indicates that the interfacing portion3102is a supplemental piece of the patient-specific model2502, though the patient-specific portion and the interfacing portion3102can be formed in a common manufacturing process (e.g., an additive manufacturing process).

As illustrated in, for example,FIGS.31-37, a patient-specific cartridge308for a surgical simulator device202may include a patient-independent frame2500(sometimes referred to herein as a standard frame) having first, second, and third openings2609,2611, and2613, and a patient-specific cardiac model2502. The patient-specific cardiac model2502may include a right atrium2506, a left atrium2504and a septum112′ having mechanical and anatomical shape properties that correspond to the mechanical and anatomical shape properties of the left atrium102and the septum112of a patient, a superior vena cava interfacing portion3100that deviates from the anatomical shape of the superior vena cava of the patient and extends between the right atrium2506and the first opening2609in the patient-independent frame2500: an inferior vena cava interfacing portion3103that deviates from the anatomical shape of the inferior vena cava of the patient and extends between the right atrium2506and the second opening2611in the patient-independent frame2500, and an upper pulmonary vein interfacing portion3102that deviates from the anatomical shape of the pulmonary vein of the patient and extends between the left atrium2504and the third opening2613in the patient-independent frame2500. The patient-specific cardiac model2502may also include a left atrial appendage116′ having mechanical and anatomical shape properties that correspond to the mechanical and anatomical shape properties of the left atrial appendage116of the patient.

FIGS.38A and38Brespectively illustrate misaligned patient-specific superior vena cava and inferior vena cava interfacing portions3802and3800that do not align with standard frame2500, and corresponding interfacing portions3100and3102of a patient-specific model that deviate from the patient-specific forms of3802and3800to couple to openings2609and2611of a patient-independent frame2500.FIG.39illustrates another view of the misaligned patient-specific superior vena cava and inferior vena cava interfacing portions3802and3800(which would not be manufactured), the corresponding interfacing portions3100and3102coupled to openings2609and2611, and an additional portion3900of the model that can be removed after manufacturing or omitted from manufacturing, to form an opening2600into the right atrium of the model.

FIG.40illustrates various aspects of a process for manufacturing a patient-specific cardiac model2502for coupling to a patient-independent (standard) frame2500, according to aspects of the disclosure. As indicated inFIG.40, during the design phase of the manufacturing process for a particular patient-specific model2502, the virtual patient-specific model may include patient-specific superior vena cava portion3802, patient-specific inferior vena cava portion3800, and patient-specific upper pulmonary vein portion4003, which would be misaligned with openings2609,2611, and2613of standard frame2500. 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 planes4000,4002, and4004may be identified. Portions3800,3802, and4003extending beyond respective planes4000,4002, and4004may be removed, and interfacing portions3011,3102, and3103can be designed to extend between the identified planar interfaces and the known locations of standard frame openings2609,2611, and2613. Once these interfacing portions3011,3102, and3103are 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 inFIGS.31,33,35,36,39, and40, the patient-specific cartridge308can be provided with a frame2500configured to couple the patient-specific model2502to the tank306. The frame2500can include first, second, and third openings2609,2611, and2613configured to align with first, second, and third access ports718,1404, and1408in the tank. As shown in these examples, the patient-specific model2502may 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 portions3100,3103, and3102that 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 openings2609,2611, and2613. The first, second, and third interfacing portions3100,3103, and3102may 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 model2502may include a simulated right atrium2506having a window2600.

Various examples discussed herein describe the advantages of providing a patient-specific model2502with 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.41illustrates, for example, a fluoroscopic image of an LAA closure device502being installed within a patient's heart, in which the shadow4102of the patient's heart and a shadow4104of the patient's spine can be seen. These shadows, while faint, can be helpful to a surgeon, in addition to ultrasound imaging with ultrasound probe505. However, as shown inFIG.42, unless the patient-specific model2502and/or other portions of station300are provided with x-ray interactive features, while the ultrasound probe505, and a guidewire507can be seen in a fluoroscopic image4200of device202, image4200does not include the shadows4102and4104. In order to include these fluoroscopic shadow features, patient-specific model2502and/or portions of station300can be provided with x-ray interactive features.

FIG.43illustrates a cross-sectional view of a portion of a wall of a patient-specific model2502of a patient's heart. As shown inFIG.43, the walls of patient-specific model2502may be formed (e.g., in a three-dimensional printing process) from an inner polymer (e.g., PolyJet) layer4302, an outer polymer (e.g., PolyJet) layer4300, and a hydrogel layer4303interposed between the inner and outer layers4302and4300. For example, inner layer4302and outer layer4300may be formed from Polyjet materials (e.g., Stratasys resins) that encapsulate hydrogel layer4303. In various implementations, hydrogel layer4303may be used as a sacrificial support material or may be used to absorb an injected aqueous liquid such as an x-ray attenuating liquid. Layers4300,4302, and/or4303may be arranged to mechanically and/or acoustically mimic the anatomical features of patient cardiac structures.

In order to provide a patient-specific model2502that generates a cardiac shadow similar to cardiac shadow4102ofFIG.41, the patient-specific model2502may be provided with x-ray interactive material. For example, as shown inFIG.44, patient-specific model2502may be provided with an x-ray interactive coating4400(e.g., an x-ray attenuating 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 layer4300(and/or on inner layer4302).

Additionally, or alternatively, hydrogel layer4303may be injected with an x-ray interactive material (e.g., a contrast liquid including calcium, iodine, and/or barium such as Iohexol).FIG.45illustrates a process for injecting an x-ray reactive material such as an x-ray attenuating material into a wall of a patient-specific model of a patient's heart, according to aspects of the disclosure. As shown inFIG.45, layer4303may be injected with an x-ray attenuating aqueous liquid to form an x-ray attenuating internal layer4502for patient-specific model2502. The injected X-ray attenuating aqueous liquid may diffuse inside the hydrogel layer4303to obtain a homogenous X-ray absorption characteristic all over the model2502to reproduce the heart shadow described above in connection withFIG.41. Coating and/or injection of x-ray attenuating materials for patient-specific model2502can be performed during a post-processing of the model (e.g., following an additive manufacturing process to generate the model). In the example ofFIG.45, the patient-specific model2502includes at least one wall portion having an outer layer4300, an inner layer4302, and an x-ray attenuating material4502interposed between the outer layer and the inner layer.

The features described above in connection withFIGS.44and/or45may provide patient-specific cartridge308with fluoroscopic features that cause the patient-specific model2502to generate a cardiac shadow similar to cardiac shadow4102ofFIG.41, under x-ray imaging of station300and cartridge308installed therein.

FIG.46illustrates a perspective view of a spinal shadow card4600that can be provided in station300to generate, under x-ray imaging, a spinal shadow similar to spinal shadow4104ofFIG.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 inFIG.46, spinal shadow card4600may include a substrate4602and a spinal simulation feature4604formed on the substrate. Spinal simulation feature4604may be printed on, embedded within, etched in, or otherwise formed on or in substrate4602. For example, spinal simulation feature4604may be a radio opaque ink printed on an x-ray transparent substrate4602. Spinal simulation feature4604may 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.47illustrates a side view of a station300of a physical simulator device202showing how a spinal shadow card4600may be disposed within the station beneath bottom wall4700of tank306. 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 station300will include a simulated spinal shadow caused by spinal simulation features4604.

As illustrated byFIG.47, a surgical simulation device202may be provided that includes a station300having a housing309, a tank306formed in the housing and configured to receive a patient-specific cartridge308that includes a patient-specific model2502of at least a portion of a heart of a patient, where the tank306has a bottom wall4700having a first surface that forms a bottom surface1402of the tank, and an opposing second surface, an esophageal access system700extending within the housing between an esophageal access port304on the housing and a first port714in the tank, a vascular access system302including a first end with a vascular access port310and a second end configured to be fluidly coupled to a second port718in the tank, and a spinal shadow simulation card4600disposed within the housing309adjacent the opposing second surface of the bottom wall4700of the tank. The patient-specific model2502includes mechanical and acoustic features that correspond to mechanical and acoustic features of the heart of the patient. The esophageal access system700is configured to allow access to the tank306by an ultrasound probe505for ultrasound imaging of the patient-specific cartridge308.

FIGS.48-57illustrate various aspects of fluid flow control system909of a physical simulator device202. For example,FIG.48illustrates a schematic view of a fluid flow control system909that includes an outlet pipe4804and an inlet pipe4814fluidly coupled to tank306via openings4800and4802of a physical simulator device202(e.g., corresponding to openings1406and1410ofFIG.14, respectively). In the example ofFIG.48, outlet pipe4804includes a filter4806, and a pump4808that controls the flow of blood simulation fluid307through pipes4804and4814and tank306. In the example ofFIG.48, inlet pipe4814includes a chamber4810having an air cavity4812for removal of air bubbles from the blood simulation fluid307that could otherwise negatively impact ultrasound imaging.

FIG.49illustrates a schematic view of another implementation of fluid flow control system909in which an additional outlet pipe4909extending between additional opening4905to filter4806, and a heater4900coupled to a power supply4902are provided. Heater4900may be powered by power supply4902(e.g., a battery within station300) to heat blood simulation fluid307(e.g., to approximately 37.5 degrees Celsius).

In the examples ofFIGS.48and49, a fluid control system909is provided in the station300, and configured to circulate a blood simulation fluid307through the tank306at least a portion of the patient-specific model2502. The fluid control system909includes an outlet pipe (e.g., pipe4804and/or4909) coupled to a first opening (e.g.,4800or4905) in the tank, an inlet pipe (e.g., pipe4814) coupled to a second opening (e.g., opening4802) in the tank, and a pump4808configured to move the blood simulation fluid307through the inlet pipe, the tank, and the outlet pipe. The fluid control system909may also include a filter4806on the outlet pipe. The fluid control system may also include a heater4900disposed between the pump4808and the second opening. The fluid control system909may also include a chamber4810having an air cavity4812disposed between the pump and the second opening and/or between the heater and the second opening.

FIG.50schematically illustrates a functional procedure of the heating system for the station300, including during a preparation operation, a use operation, and a flush operation. The preparation operation may include operation of an accessory fluid heater temporarily attached to the station300, according to aspects of the disclosure.

FIG.51illustrates a perspective view of an accessory fluid heater5100that can be provided for a physical simulator device202, according to aspects of the disclosure. As shown inFIG.51, in one implementation, an accessory heater5100may include a mounting structure5102configured to removably attach to a sidewall5110of station300, and configured to hold a temperature sensor5104, and a resistive heating element5106within fluid307in tank306.

FIG.52illustrates a cross-sectional view of a mounting member5102, installed on sidewall5110of station300. As shown inFIG.52, mounting member5102may be arranged to wrap around and over the top of sidewall5110(e.g., secured by a friction fit), while holding temperature sensor5104and resistive heating element5106in a desired position. Resistive heating element5106may be provided in tank305, in a feedback loop with temperature sensor5104, to rapidly heat the blood simulation fluid307(e.g., to 37.5 degrees Celsius) prior to a simulated surgical procedure, the fluid thereafter being held at the desired temperature by internal heater4900(seeFIG.49). Resistive heating element5106may be powered by an external power source5108.

FIGS.53A,53B, and53Cillustrate various features of another implementation of an accessory heater for physical simulator device202.

For example, as shown inFIG.53A, an accessory heater5300may be provided that includes two mounting portions5304, configured to wrap around and over opposing sidewalls5110and5112of station300, and a cap portion5302extending between the two mounting portions5304.

FIG.53Billustrates a cross-sectional view of a mounting portion5304of the accessory fluid heater5300ofFIG.53A. As shown inFIG.53B, mounting portion5304may include a first vertical extension5308having a first magnet5306and a second vertical extension5310having a second magnet5313. As shown, sidewall5112of tank306may include magnets5309and5311configured to magnetically engage with magnets5306and5313of mounting portion5304to temporarily secure accessory heater5300to tank306. Sidewall5110may include magnets similar to magnets5309and5311, for magnetically engaging with magnets in the other mounting portion5304of accessory heater5300. As shown inFIG.53C, a resistive heating element5390may extend from cap portion5302into blood simulation fluid307(when mounting portions5304are mounted to sidewalls5110and5112) to rapidly heat fluid307(e.g., to 37.5 degrees Celsius) prior to a simulated surgical procedure.

As shown inFIG.54, physical simulator device202may include a flush system5400configured to couple to station300for flushing blood simulation fluid307from station300. As shown inFIG.54, flush system5400may include external flush tubing5404that extends between a flush valve5402and a flush receptacle5406. In some implementation flush system5400may include an external flush pump (e.g., as shown on flush tubing5404ifFIG.54). Additionally or alternatively, station300may include a pump that can be used for flushing fluid to fluid tubing5404.

FIG.55shows how, internally to station300, fluid flow system909may include a Y-pipe5500at an intersection between outlet pipe4804and inlet pipe4814before flush valve5402.FIG.55includes arrows that illustrate the fluid flow within outlet pipe4804and inlet pipe4814(noting that other features of fluid control system909such as heater4900, pump4808, and chamber4810are not shown inFIG.55for clarity of the present description) when flush valve5402is closed. In contrast,FIG.56includes arrows that illustrate the fluid flow within outlet pipe4804, inlet pipe4814, and flush tubing5404when flush valve5402is open.FIGS.55and56each also include an enlarged view of Y-pipe5500showing how the Y-pipe may include a restricted portion5509between outlet pipe4804and flush portion5512, at the location of the intersection with a return section5510to inlet pipe4814, to create a venturi effect to help facilitate flushing of the system.FIG.57illustrates a cross-sectional perspective view showing further details of the constriction of Y-pipe5500. The venturi effect generated by the constriction of the Y-pipe5500allows pump4808in the station300to be used to circulate fluid within the station, and to generate an aspiration to flush the station. The constriction5509may narrow the diameter of pipe4804from, for example, approximately 10 mm to approximately 8 mm, 6 mm, or 4 mm (as examples). In the examples ofFIGS.54-57, the fluid control system909includes a Y-pipe5500disposed between the flush valve5402and both the inlet pipe4814and the outlet pipe4804for tank306.

FIG.58illustrates 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 ofFIG.58, distal support3110of patient-independent frame2500may first be placed into position against access port718in sidewall1491of tank306, while base portion3108of frame2500is rotated toward bottom wall4700of tank306, until base portion3108contacts bottom wall4700and portion3112is in contact with sidewall1489, as shown inFIG.59.

FIG.60shows how portion3112of frame2500can include engagement features such as magnets6000. As shown inFIG.61, sidewall1489of tank306may be provided with corresponding engagement features6100for engagement with engagement features6000on frame2500, to secure cartridge308within tank306. For example.FIG.62includes arrows6200illustrating a magnetic engagement between portion3112of frame2500and sidewall1489of tank306. Magnets6000, disposed on the patient-independent frame2500(e.g., along with magnets6100in the sidewall of tank306) help facilitate plug-and-play installation and removal of the patient-specific cartridge308in the surgical simulator device202.

In the examples ofFIGS.60-62, the frame2500includes a base portion3108configured to abut a bottom surface1402of the tank306when the patient-specific cartridge308is installed in the tank. The frame2500also includes an opening2609configured to align with an access port718on a first sidewall1491of the tank306, and a proximal portion3112including at least one engagement member (e.g., one or more of magnets6000) configured to engage with a corresponding engagement member (e.g., one or more of magnets6100) on an opposing second sidewall1489of the tank306.

FIG.63shows how, when magnetic engagement between portion3112of frame2500and sidewall1489of tank306holds a first side of frame2500in place within tank306, an engagement between access port718and distal portion3110of frame2500may hold the opposing side of frame2500in place within tank306.

As one illustrative example of a method of using the technology disclosed herein, a method is described that includes providing a surgical simulation device202having a station300having a housing309, a tank306formed in the housing309, and a vascular access system302coupled to the housing. The method may include providing, in the tank306, a patient-specific cartridge308that includes a patient-specific model2502of at least a portion of a heart of a patient. The method may also include inserting an imaging device, such as an ultrasound probe505, through an esophageal access system700within the housing from an esophageal access port304on the housing, though a first port714in the tank, and into a recess1400in a bottom surface1402of the tank306beneath the patient-specific cartridge308. 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 port310of the vascular access system302, through a main lumen1700of the vascular access system, and into a portion of the patient-specific model2502via a second port718in the tank306. The method may also include, prior to providing the patient-specific cartridge308in the tank306, coupling first, second, and third interfacing portions3100,3103, and3102of the patient-specific model2502to corresponding first, second, and third openings2609,2611, and2613in a frame2500of the patient-specific cartridge308. The method may also include circulating a blood simulation fluid307through the tank306and at least portions of the patient-specific model2502(e.g., using fluid control system909). The method may also include heating the blood simulation fluid307with a heater4900in the station300. The method may also include, prior to heating the blood simulation fluid307with the heater4900in the station300, pre-heating the blood simulation fluid307with an accessory heater (e.g., accessory heater5100or accessory heater5300) configured to attach to at least one sidewall5110of the station300. The method may also include obtaining fluoroscopy images of the patient-specific cartridge308using x-ray attenuating material in or one the patient-specific model2502, while the patient-specific cartridge is in the tank.

The patient-specific model may include a right atrium, a septum, and a left atrium, and the method may include inserting, via the second port in the tank, the surgical element into the right atrium of the patient-specific model. The method may also include puncturing the septum of the patient-specific model with the surgical element. The method may also include passing a device through the punctured septum into the left atrium of the patient-specific model. The patient-specific model may also include a left atrial appendage, and the method may also include occluding the left atrial appendage of the patient-specific model with the device. The septum, the left atrium, and the left atrial appendage of the patient-specific model have mechanical and acoustic characteristics that correspond to mechanical and acoustic characteristics, respectively, of a septum, a left atrium, and a left atrial appendage of the patient. The method may also include generating an ultrasound image of the patient-specific cartridge using the imaging device.

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.