The Design History of the Artificial Heart by Roberto S

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Msc. Mechanical Engineering

CME8056

Manufacturing, Materials and Processes

“The design history of the artificial heart”

By Roberto Sacoto M.

Student number: 120395769

28/04/2014

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The design history of the artificial heart

Introduction

The heart is one of the most important organs in the human body, even to have pulse, is

considered as sign of life. A great quantity of people around the world suffers of heart failure,

and in numerous cases when the heart condition is severe, is strictly mandatory to make a

heart transplant. Moreover, in the world exists a high demand of heart donors, but there is no

possibility to cover it. For this reason, the necessity to create an alternative to replace the ill

heart marked the origin of the artificial heart.

Along the history, the development of the artificial heart have passed through many

contemplations, since the early models across to the current day versions, where new

technology and design has been applied trying to achieve always better results. As Sheppard

comments, several years have passed since the first successful heart-‐lung machine was applied

on a human in 1953. However, four years after the first “artificial heart” (made from plastic)

was implanted inside a dog. Subsequently, since the decade of 1960s some devices were

developed with limited achievements.

In the year of 1982 the first successful artificial heart transplant was performed, where the

patient survived 112 days. This fact brought plenty interest for the developing of the total

artificial heart (TAH). This included new studies of the technology used in this mechanical

device, in order to improve the compatibility between both the human body and the artificial

heart to avoid the rejection of it, or any other possible problems, such as infections provoked

after the implantation of the artificial device. According to a report from the Natural Heart

Institute, the ideal materials to be used need to have some the next characteristics: should not

modify blood or tissue electrolyte composition, not cause allergic or toxic reactions and must

not interfere with the body’s normal defence mechanisms to prevent cancer generation and

harm the blood and tissues. Although the heart is conceptually a simple organ (a muscle that

works as pump), it involves complex finesses that challenge the direct simulation using power

supplies and synthetic materials.

In these days the artificial heart has been used for temporary support until a natural heart can

be transplanted, which is a considerable limitation because the native heart is removed.

Nevertheless, this inconvenient encouraged the development of the ventricular assist devices.

In this work some of the most relevant artificial heart devices are going to be discuss, with the

intention to highlight their achievements and limitations. Moreover, is important to say that

every one of them has been important in the field of medicine research.

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The artificial hear through the time

Early models

The Liotta Total Artificial Heart

This device is considered the first artificial

heart implanted in a human. Developed in

the decade of 1960s by Dr. Domingo Liotta,

it was implanted in a 47-‐year-‐old patient.

Work description and materials technology

This apparatus was a pneumatic pump with

double-‐ventricle input and output. Four

valves controlled the flow of blood across

the intake and outtake areas of the pump.

Basically, it was handmade with materials

like polyester (Dracon) and silicon (Silastic) tubing. The figure 1 shows the needlework used to

join the tubing with chamber fabric. An external unit controlled the two pneumatic units that

generated the vacuum and pumping actions to move the blood across the mechanical heart.

Akutsu III Total Artificial Heart

In the year of 1982, a new prosthesis

designed by Dr. Tetsuzo Akutzu was

implanted on a 36-‐year-‐old man.


This device contained two double-‐

chambered pumps powered by air. The

prosthetic ventricles were attached to the

remnants of the natural heart’s atria and

the vessels by flexible detachable quick-‐

connectors. The control console had a large size and a more complex control system. The

figure 2 shows the orthotopic placement of the device.

Design Achievements:

-‐ Complete artificial heart

-‐ Continuous-‐flow pump in humans

-‐ A new soft material was used in the pumping chambers, called Avcothane, which has

the property to resist to the bacteria development.

Figure 1. Liotta total artificial heart http://www.theatlantic.com/technology/archive/2010/10/the-‐worlds-‐first-‐artificial-‐heart/63949/

Figure 2. Diagram showing the orthotopic placement of the Akutsu III TAH

Total artifical heart in two stages transplantation

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Limitations

-‐ Skin-‐piercing tubes (infections may occur)

-‐ Not portable and very complex system

-‐ Complex control system and short term support

Jarvik 7 Total Artificial heart

Designed to work as a natural heart by Dr. Robert Jarvik, the

Jarvik 7 (fig. 3) was successfully implanted in 1982. The

patient survived 112 days with this artificial device (Franklin

Inst.).


As an improving in the design this device had two pumps

much similar to the hearts ventricles. The polyurethane

ventricles where sphere-‐shaped, and had a disk-‐shaped

mechanism to push the blood from the inlet valve to the

outlet valve. As its predecessors, polyester was still used in

cuffs to attach the device to the natural heart’s atria. Also

aluminium was used on the valves internal parts. The artificial heart’s pneumatic out drivelines

were made of polyurethane tubing. At the skin exit the drivelines were covered with velour-‐

covered Silastic material to encourage tissue generation.

The mechanical heart was pneumatic powered by an external control system. The control

console was large and heavy. However, it has a more detailed control panel that allowed the

doctors to manage the control pump rate, pumping pressure and other functions.


-‐ More efficient design (truly successful artificial heart, longer support time)

-‐ Better manufacturing quality and control safety improvement

-‐ Patient is transportable (the external control system included air scuba and battery

power back up during transportation)

Limitations:

-‐ Large external console

-‐ Was not permanent

-‐ Skin-‐piercing tubes and health risks (compatibility rejection and organ failure had

presented in some cases)

Figure 3. Jarvik 7 total artificial heart

http://www.smithsonianlegacies.si.edu/objectdescription.cfm?ID=172

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Actual models

SynCardia Total Artificial Heart

The Syncardia total artificial heart is a design based on

the previous Jarvik 7 model (Texas Heart Institute).

However it has been developed with new more

reliable materials.


It is basically a pneumatic pump, externally air

powered. The base assembly is fabricated form

IsoPlast, engineered polyurethane. The doom-‐like

thermoplastic chamber housing is fabricated from

segmented polyurethane solution (SPUS), overlaid on

a Dracon Mesh. Multiple layers of SPUS are utilized to

fabricate the blood chamber, all applied via sequential

pouring over a mould. As can be appreciated in figure 4, this device has the option of a

portable external device, which allows the patient to be transported and perform some daily

activities.


-‐ Smaller and More efficient design (longer support time, used as a bridge between

transplant, approximate time of 18 months)

-‐ Use of reliable materials and better manufacturing control

-‐ Portable control device available to transport the patient

-‐ Heart system repair and calibration can be made externally

Limitations:

-‐ Skin-‐piercing tubes (infections may occur)

-‐ Temporary Treatment (bridge), very expensive

AbioCor Total Artificial Heart

The AbioCor TAH is the first completely self-‐contained total artificial heart.


Dissimilar to the artificial hearts of the past, patients are not tied to a large, air-‐pumping

console nor do they have wires or tubes piercing their skin. The internal device it’s a motor-‐

driven hydraulic pump. The pressure is created by the motors rotation between 4000 to 8000

rpm. The figure 5 indicates the internal system of the AbioCor TAH, which apart has an

Figure 4. Syncardia total artificial heart connected to a portable control device http://transplants.ucla.edu/body.cfm?id

=223

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emergency rechargeable battery that is continuously charged by an external power source. A

big difference from the other TAH is that this device has

a wireless energy transfer system that is based on a

transcutaneous energy transmission. The Texas Heart

Institute describes that it consists of internal and

external coils that are used to transmit power across

the skin. Because tubes or wires do not pierce the skin,

the chances of developing an infection are decreased.

External battery packs can power the AbioCor for 4

hours.

Achievements:

-‐ Internal powered device with internal control

drive system

-‐ Completely self-‐portable (compact, safe, life

time of 2 years approx.)

-‐ AngioFlex and Titanium conform the principal

materials of the device.

-‐ Less risk o infection due to no skin-‐piercing wires and tubing.

Limitations:

-‐ Heavy (2 pounds approx.) and large size device – only fits 50% of U.S. males (Luber)

-‐ Limited battery life (4 hours)

-‐ Complicated anticoagulation management

-‐ Very expensive (around 250000 dollars, Washington Post)

Novel devises

Carmat Hydraulic Artificial Heart

It consists of two cavities, imitating the organ’s

ventricles, which are separated by a moving membrane

that’s hydraulically powered via a special drive fluid. This

membrane reproduces the action of the ventricular wall

during contractions, creating blood flow in and out of

the device. The system works in conjunction with

sensors and a microcontroller that continuously adjust

the activity of the prosthesis to match the needs of the

Figure 5. AbioCor total artificial heart system

http://texasheart.org/Research/Devices/abiocor.cfm

Figure 6. Carmat Hydraulic Artificial Heart http://www.medgadget.com/2013/05/carmat-‐hydraulic-‐artificial-‐heart-‐set-‐to-‐

begin-‐human-‐trials-‐wvideo.html

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patient. (Fig.6). The whole device is covered by compatible polymer membrane that emulates

a heart tissue. Also, all controls and sensors are internally installed.

No pulse artificial heart

This novel device (fig. 7) has been developed in

the Texas Heart Institute during the last 10

years. It was successfully implanted in the year

of 2011 in a man.

What makes it great is that this device does not

simulate the heart beating. This characteristic

defies all the actual knowledge of the human

body system, which strongly believes that

heartbeat is an important key to define the life

in the human body.

This device works as continuous turbine pump

capable to rotate at more than 10000 rpm,

leaving the patient with absolutely no pulse. It

still under development and is one of the most promising devises in the future of the cardiac

prosthesis.

Ventricular assist devices

Depending on the patients case, not always is

necessary to make a total heart transplant,

for some cases a ventricular assist device can

be use. It is a mechanical pump that is used to

support heart function and blood flow in

patients who have debilitated hearts.

Practically the design, materials and control

technology are similar to the previous

devices. However, these kinds of devices are

less invasive, which means that the heart is

not totally extracted and in some cases it can

recover its health. Figure 8 shows a

ventricular assist device installed in a patient

to help the ill heart.

Figure 7. No pulse artificial heart device http://www.kollected.com/Artificial-‐Heart

Figure 8. Ventricular assist device (Thoratec HeartMate II LVAS)

http://texasheart.org/Research/Devices/thorate

c_heartmateii.cfm

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Conclusions

In conclusion, the last 50 years have marked a new era in the artificial organs development.

Each created device has contributed for the medical advance. Due to the necessity to fusion

the artificial device with the human body, the experimentation with new materials and power

sources increased. Although the essence of the artificial heart have not changed considerably,

new materials and technology has been applied. Since basic polymers as plastic, through more

complex polyurethane shapes, the improvement of materials is now significant advanced.

However, in the case of power sources it is still difficult and controversial. Actually, all the

artificial heart devices needs from an electrical or pneumatic power source to work, which has

been a difficulty for the system, due to the risks of infections and other problems that can

cause to the patients. However, the transportability of the person is now a reality. Backpacks

filled with lithium batteries supports the power to the mechanism system, contrasting with the

early days of the artificial heart when the patient was not able to leave the bed of the hospital.

Perhaps, in the future these mechanical devises will be able to be powered by the own human

organism, as the intention to work as one. Another remarkable event is the development of

the no pulse devise. As written before, it simply defies the previous knowledge of the human

heart, diminishing the heartbeat as one of the essential characteristics, which may influence

the future design of the total artificial heart.

Finally, the artificial heart implant shall continue to catch the public’s imagination, possibly

because the idea of it seems captivating out of this world. Hopefully, future investigations will

achieve this big goal, however it may take some several years until all the technology needed

will be available, or better say developed by the scientists.

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References

-‐ Abiomed (19/04/2014) AbioCor [WWW Document]. URL

http://www.abiomed.com/products/heart-‐replacement/

-‐ AlNuaimi A, Mohamend N., et all. (22/04 /2014) Artificial Heart [WWW Document]. URL

http://forum.panet.co.il/showthread.php?t=49818

-‐ Baum D. (21/04/2014) No Pulse: How Doctors Reinvented The Human Heart [WWW

Document]. URL http://www.popsci.com/science/article/2012-‐02/no-‐pulse-‐how-‐doctors-‐

reinvented-‐human-‐heart

-‐ Brown D. (24/04/2014) Artificial Heart Gets Limited FDA Approval [WWW Document]. URL

http://www.washingtonpost.com/wp-‐

dyn/content/article/2006/09/05/AR2006090501309.html

-‐ Cooley D. , Akutzu T, et all. (1981)Total artifical heart in two stages transplantation.

Cardiovasc Dis. Sep 1981; 8(3): 305–319.

-‐ Kollected (25/04/2014) No Pulse: How Doctors Reinvented The Human Heart [WWW

Document]. URL http://www.kollected.com/Artificial-‐Heart -‐ Lubher S. (20/ 04/ 2014) The AbioCor system: Overview [WWW Document]. URL

http://www.slideshare.net/saluber/the-‐abiocor-‐system-‐overview

-‐ Madrigal A (20/ 04/ 2014) The World's First Artificial Heart [WWW Document]. URL

http://www.theatlantic.com/technology/archive/2010/10/the-‐worlds-‐first-‐artificial-‐

heart/63949/

-‐ Mallari K. (20/04/2014) Fake Hearts, Anyone? [WWW Document]. URL

http://agham.asti.dost.gov.ph/1998/4th/extras/astra1.htm

-‐ Medgadget (22/04/2014) CARMAT Hydraulic Artificial Heart Set to Begin Human Trials

[WWW Document]. URL http://www.medgadget.com/2013/05/carmat-‐hydraulic-‐

artificial-‐heart-‐set-‐to-‐begin-‐human-‐trials-‐wvideo.html

-‐ Sheppard L. (20/04/2014) Artificial Heart [WWW Document]. URL

http://www.madehow.com/Volume-‐6/Artificial-‐Heart.html#ixzz2zRZGH8xC -‐ Slepian M, Alemu Y., et all (2012) The SyncardiaTM total artificial heart: in vivo, in vitro, and

computational modeling studies. Pages 267-‐274

-‐ Smithsonian institution Press (20/ 04/ 2014) Jarvik-‐7 artificial heart, 1985 [WWW

Document]. URL http://www.smithsonianlegacies.si.edu/objectdescription.cfm?ID=172

-‐ SynCardia Systems Inc. (23/04/2014) Total Artificial Heart Facts [WWW Document]. URL

http://www.syncardia.com/total-‐facts/total-‐artificial-‐heart-‐facts.html

-‐ Texas Heart Institute (21/04/2014) Heart Assist Devises [WWW Document]. URL

http://texasheart.org/Research/Devices/thoratec_heartmateii.cfm

-‐ UCLA Transplantation Services (19/04/2014) SynCardia Total Artificial Heart [WWW

Document]. URL http://transplants.ucla.edu/body.cfm?id=223

Documents

The Design History of the Artificial Heart by Roberto S