There currently exists no commercially available cardiovascular device for testing intracardiac devices or protocols associated with such devices. A model has been constructed for Vanderbilt
University Medical Center (VUMC) but the model is experiencing the following issues: leaking, inability to visualize devices or flow through system, lack of portability, absence of flow gradient.
Cardiovascular Model
The system consists of acrylic tubing mimicking the inferior venous system, an egg shaped acrylic block with 4 chambers hollowed to represent the atria and ventricles, 2 bioprosthetic 3 leaf valves between each atrium and ventricle, and an axial pump for generating a venous flow gradient.
The system will function in the testing of newly developed devices, including bioprosthetic heart valves, bovine and porcine valves, catheters: both steerable and non, and intracardiac devices intended for reaching the septum. Further, the device will be used for developing cardiac procedures associated with the aforementioned devices and for training doctors and operating room staff for these procedures.
The system environment will be a research lab in the Cardiology department at VUMC. Systems interacting with the model include the devices tested on the model and the individuals operating the model. The model will be transported on airplanes and thus will face turbulence. Otherwise, the model will be stored at room temperature and will not face increased humidity or other deteriorating environments.
Problems that should be resolved include the problems with the current model used by VUMC
Cardiology. These issues include: leaking at joints connecting venous returns and venous inflow and outflow from the heart, lack of portability, inability to modulate the heart (including interior), inability to visualize flow at joints due to the presence of silicon, lack of realistic heart shape, and lack of simple aesthetics.
Poor design considerations are the main mechanisms underlying the problems with the current model. There is no generalized cardiovascular model commercially available because biotechnology firms are establishing models for device specific testing, such as fatigue testing on heart valves.
The most fundamental undesired consequence of the unresolved problem is leaking of the system which results in water loss. The second undesired consequence resulting from the absence of a pump is inability to empty the water from the model for transportation. Finally, the model cannot be broken down smaller parts for transportation.

Historically, few models have been created and those that exist are designed to test specific devices. Currently existent models include the following:
1. A patented model for prosthetic tricuspid valve replacements. The leaflet valve is exposed to in vivo loading including forward pressure applied to the valve and backflow pressure on the valve.
2. In a second model, an agar gel with characteristics of biological tissue was used to model left ventricular and aortic chambers for which ultrasound imaged flow dynamics through bicuspid valve.
3. Finally, a device exists for testing ventricle assist devices which models pumping performance and flow dynamics with resistance comparable to native heart.
One model has been established for VUMC Cardiology with the following problems: leaking at joints connecting venous returns and venous inflow and outflow from the heart, lack of portability, inability to modulate the heart (including interior), inability to visualize flow at joints due to the presence of silicon, lack of realistic heart shape, and lack of simple aesthetics.
The problems with the current systems have been identified. It is the goal of this design to improve upon these problems in the design of the future model.
Ideally the model will have the following characteristics:
1. A pressure gradient using a cyclic pump (10 mmHg)
2. Model inferior systemic venous flow in a closed circuit, returning fluid to the heart
3. Hinging of the heart to increase ease of modulating inner chambers of heart, including the valves and septum
4. Be aesthetically pleasing and viewable throughout
5. Being easily portable
Resources in the design of our model will include use of currently available and applicable technologies. This will include use of a previously designed 3 leaf bioprosthetic valve, potentially one that does not meet standards for in vivo use and will be donated. The second resource will be use of an axial aquarium pump. Taking advantage of currently available technology will make the design of our model significantly simpler. Other resources include specialists in the area who will act as information resources. These individuals will be Dr. Michael Barnett with VUMC Cardiology and
Andrew Cross with the simulations lab at Vanderbilt.
1. Completely changing the system is allowed. Nonetheless, there are some fundamental aspects of the current model that do not need to be changed including the size of tubing as it is anatomically correct.
1. Performance will be assessed by how physicians interface with device and how realistically the device models cardiac procedures
2. Conclusions will be drawn on how the design implements intended design features a. Portable, Transparent, Pump, Water-tight
3. Physician input will be considered for future design improvements and used to identify drawbacks

If this device is made commercially available the market will be for all biotechnology companies and research institutions developing and testing cardiovascular devices. The market will also include hospitals for use in training doctors and OR staff. No competitors or suppliers currently exist.
1. Project name: Developing a Cardiovascular Model
2. Project objectives: To develop a prototype for testing new devices and techniques that is capable of: a. Generating a pressure gradient using a cyclic pump (10 mmHg) b. Modeling inferior systemic venous flow in a closed circuit, returning fluid to the heart c. Hinging of the heart to increase ease of modulating inner chambers of heart, including the valves and septum d. Be aesthetically pleasing and viewable throughout e. Being easily portable
3. Project Timeline: a. By December 15th- Establish CAD design of model and meet with project coordinator to discuss final design. b. By End of March- Have model constructed and ensure proper function
4. Project Team a. Jim Clear b. Chase Houghton c. Meghan Murphy
5. Contact Information: a. James.W.Clear@vanderbilt.edu b. Chase.C.Houghton@vanderbilt.edu c. Meghan.K.Murphy@vanderbilt.edu

» 1. Find a way to eliminate, reduce, or prevent [the] (The joints are inefficient) in order to avoid [the]
(Model leaks), under the conditions of [the] (Lots of silicone around joints).
2. Find a way to eliminate, reduce, or prevent [the] (Model leaks) in order to avoid [the] (Model is messy to use), under the conditions of [the] (The joints are inefficient).
3. Find a way to eliminate, reduce, or prevent [the] (Model is messy to use) under the conditions of
[the] (Model leaks) and (Model is drained my tilting).
4. Find a way to eliminate, reduce, or prevent [the] (Model is drained my tilting) in order to avoid [the]
(Model is messy to use), under the conditions of [the] (There is no way to pump out water).
5. Find a way to eliminate, reduce, or prevent [the] (There is no way to pump out water) in order to avoid [the] (Model is drained my tilting), under the conditions of [the] (There is no pump).
» 6. Find a way to eliminate, reduce, or prevent [the] (There is no pump) in order to avoid [the] (There is no way to pump out water) and (Physiological venous return is not reproduced).

7. Find a way to eliminate, reduce, or prevent [the] (Physiological venous return is not reproduced) under the conditions of [the] (There is no pump).
8. Find a way to eliminate, reduce, or prevent [the] (Lots of silicone around joints) in order to avoid [the]
(The joints are inefficient) and (Model is not entirely transparent).
9. Find a way to eliminate, reduce, or prevent [the] (Model is not entirely transparent) under the conditions of [the] (Lots of silicone around joints) and (Heart walls are opaque), then think how to provide [the] (Visualization of catheter-based surgeries).
10. Try to resolve the following contradiction: The harmful factor [the] (Model is not entirely transparent) should not exist in order to avoid harmful results and should be in place in order to provide or enhance
[the] (Visualization of catheter-based surgeries).
11. Find an alternative way to obtain [the] (Visualization of catheter-based surgeries) that offers the following: provides or enhances [the] (User satisfaction), does not require [the] (Model is not entirely transparent), is not influenced by [the] (Anatomy of the heart is not mimicked).
12. Find a way to eliminate, reduce, or prevent [the] (Heart walls are opaque) in order to avoid [the]
(Model is not entirely transparent).
13. Find an alternative way to obtain [the] (User satisfaction) that offers the following: does not require
[the] (Visualization of catheter-based surgeries) and (Showcasing procedures to other physicians), is not influenced by [the] (Model is messy to use).
14. Consider transitioning to the next generation of the system that will provide [the] (User satisfaction) in a more effective way and/or will be free of existing problems.
15. Find an alternative way to obtain [the] (Showcasing procedures to other physicians) that offers the following: provides or enhances [the] (User satisfaction), is not influenced by [the] (Model is not portable).
» 16. Find a way to eliminate, reduce, or prevent [the] (Model is not portable).
17. Find a way to eliminate, reduce, or prevent [the] (Anatomy of the heart is not mimicked) under the conditions of [the] (Heart geometry is incorrect).
» 18. Find a way to eliminate, reduce, or prevent [the] (Heart geometry is incorrect) in order to avoid
[the] (Anatomy of the heart is not mimicked).
1. Find a way to eliminate, reduce, or prevent [the] (The joints are inefficient) in order to avoid [the]
(Model leaks), under the conditions of [the] (Lots of silicone around joints).
Primary Directions
- Eliminate the cause of the undesired action of [the] (The joints are inefficient).
- Consider resources to reduce the undesired factor (The joints are inefficient).
- Isolate the system or its part from the harmful effect of [the] (The joints are inefficient).
Out-of-scope
- Counteract the harmful effect of [the] (The joints are inefficient).
- Impact on the harmful action of [the] (The joints are inefficient).

- Reduce sensitivity of the system or its part to the harmful effect of [the] (The joints are inefficient).
- Reduce the harmful results produced by [the] (The joints are inefficient).
- Apply universal Operators to reduce the undesired factor (The joints are inefficient).
- Try to benefit from the undesired factor (The joints are inefficient).
6. Find a way to eliminate, reduce, or prevent [the] (There is no pump) in order to avoid [the] (There is no way to pump out water) and (Physiological venous return is not reproduced).
Primary Directions
- Eliminate the cause of the undesired action of [the] (There is no pump).
- Consider resources to reduce the undesired factor (There is no pump).
Out-of-scope
- Isolate the system or its part from the harmful effect of [the] (There is no pump).
- Counteract the harmful effect of [the] (There is no pump).
- Impact on the harmful action of [the] (There is no pump).
- Reduce sensitivity of the system or its part to the harmful effect of [the] (There is no pump).
- Reduce the harmful results produced by [the] (There is no pump).
- Apply universal Operators to reduce the undesired factor (There is no pump).
- Try to benefit from the undesired factor (There is no pump).
16. Find a way to eliminate, reduce, or prevent [the] (Model is not portable).
Primary Directions
- Eliminate the cause of the undesired action of [the] (Model is not portable).
- Consider resources to reduce the undesired factor (Model is not portable).
Out-of-scope
- Isolate the system or its part from the harmful effect of [the] (Model is not portable).
- Counteract the harmful effect of [the] (Model is not portable).
- Impact on the harmful action of [the] (Model is not portable).
- Reduce sensitivity of the system or its part to the harmful effect of [the] (Model is not portable).
- Reduce the harmful results produced by [the] (Model is not portable).
- Apply universal Operators to reduce the undesired factor (Model is not portable).
- Try to benefit from the undesired factor (Model is not portable).
18. Find a way to eliminate, reduce, or prevent [the] (Heart geometry is incorrect) in order to avoid [the]
(Anatomy of the heart is not mimicked).
Primary Directions
- Reduce sensitivity of the system or its part to the harmful effect of [the] (Heart geometry is incorrect).
- Consider resources to reduce the undesired factor (Heart geometry is incorrect).
- Eliminate the cause of the undesired action of [the] (Heart geometry is incorrect).
Out-of-scope
- Isolate the system or its part from the harmful effect of [the] (Heart geometry is incorrect).
- Counteract the harmful effect of [the] (Heart geometry is incorrect).
- Impact on the harmful action of [the] (Heart geometry is incorrect).
- Reduce the harmful results produced by [the] (Heart geometry is incorrect).
- Apply universal Operators to reduce the undesired factor (Heart geometry is incorrect).
- Try to benefit from the undesired factor (Heart geometry is incorrect).

- Insert pump in series with the circuit
- Create draining hole near bottom of device
- Manufacture a heart in an oval rather than cube acrylic shape
- Replace plastic tubing with acrylic tubing
- Replace silicone with chloroform as adhesive
- Use basin to catch any leaking from model
- Convert to modular design for more compact transport
- Hinge heart for viewing of right atria-ventricle valve
Easy drainage of device – Pump insertion and drainage hole near bottom of device
Insert the pump near the drainage hole so that water is pumped out of the device
Device leakage
Modular construction and hinging of the heart counteract water tightness
Combine water collecting devices around module connectors to collect leaking water
Use of chloroform at solid acrylic tubing joints to eliminate leaks
Other ideas are independent concepts
In order to segment the device, build modular interconnecting components. This will allow for the compaction of the device for easier transport.
Other lines of evolution currently do not apply to solving problems of the device.
Once model has been constructed after implementing design ideas we will evaluate whether goals have been adequately reached.
Potential failures include leakage of device at module joints and at heart hinge joints. Research will need to be done to identify solutions to these problems, complete with trial and error analysis.
Implement design ideas, with concern being taken to prevent leakage of device especially given the modular construction.