advancements in artificial hearts

8/18/2019 Advancements in Artificial Hearts

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BRIDGING THE GAP TO HEART TRANSPLANTATION

Jessica Zurcher

Indiana Institute of Technolo!

A"stract# The $ro"le% of desinin and i%$le%entin

a &ia"le aid for heart trans$lant $atients a'aitin a

donor heart has "een a focal $oint of cardiac research

for decades due to the %onths and so%eti%es !ears a

$atient %ust 'ait "efore a donor heart "eco%es

a&aila"le in his or her area( Since the earl! )*+,-s

technolo! has "een de&elo$ed to hel$ to "ride this

a$ "et'een the ti%e a $atient is $ut on the donor list.until the $atient actuall! recei&es a donor heart( The

technoloies that ha&e de&elo$ed to assist this $rocess

are &ast( Ho'e&er. the artificial heart as 'ell as

technoloies used to /ee$ the donor oran functional

for loner $eriods of ti%e 'ill "e e0a%ined( The

functionalit! and the histor! of the artificial heart 'ill

"e descri"ed( The su"stantial i%$ro&e%ents in

dura"ilit!. 1ualit! of life. sur&i&al to trans$lantation.

and the decrease in related co%$lications as a result of

de&elo$in technoloies 'ill "e e0a%ined( The total

artificial hearts that 'ill "e discussed include the earl!

Jar&i/23 artificial heart as 'ell as the 4ardio5est and

the A"io4or artificial heart( The technoloiesde&elo$ed that /ee$ the donor orans &ia"le $rior to

trans$lantation are the 6aso5a&e s!ste% as 'ell as

the Trans7edics oran care s!ste%(

The use of these technoloies has reatl! i%$ro&ed the

1ualit! of life. lone&it! of orans. as 'ell as the life

e0$ectanc! of $atients 'ho ha&e recei&ed donor

orans( The de&elo$%ents in these technoloies ha&e

decreased co%$lications in heart trans$lant $atients.

'hile hel$in to /ee$ the $atient health! and acti&e

until the surer!( The continued i%$ro&e%ents on

these technoloies to further increase $atient lone&it!

as 'ell as %ini%i8e co%$lications 'ill "e interal in

the future of cardiac %edicine(

9e!'ords# 4ardio5est. A"io4or. A"io7ed.

S!ncardia. artificial heart. O4S. 6aso5a&e.

Trans7edics. cardiac. trans$lant. "ride to

trans$lantation(

I( Introduction#

The bridge to cardiac transplantation has become a much

longer road in the most recent years. Today, the average

timeline between transplant list and cardiactransplantation is over one year [1]. This is due to a higher

demand for organs than are available.

On average, only 4% of all organ donors produce viablesolid organs [1]. Of this remaining number of organ

donors, !% actually donate their heart for use. Of these

available hearts, very few actually ma"e it into another

person due to geographic restraints. On average, a heartcan survive outside of the body for si# hours before it is

considered unable to be transplanted [1].

$ue to this gap, thousands of patients have suffered and

many have died awaiting a donor organ to become

available. To help patients survive to cardiac

transplantation, several technologies have been developedincluding the artificial heart, eft &entricle 'ssist $evices

(&'$), inotropic therapies, and devices that increase thelongevity of a recently donated organ.

II( The Artificial Heart#

' total artificial heart is a mechanical device that

surgically replaces both ventricles and all valves of aheart. The first successful total artificial heart transplant in

a living being occurred in 1*+ with the transplantation of

a total artificial heart into a dog at the -leveland -linic.

nfortunately the animal died after *! minutes. /oonafter, in 1*0*, the first successful transplantation of an

artificial heart into a human being occurred. The patient

survived three full days with the artificial heart, but diedsoon after transplantation [].

These early applications of the artificial heart finally gave

way to the first widely publici2ed transplantation of a

permanent total artificial heart on $ecember 1, 1*3 [].The man, named arney -lar", was ineligible for heart

transplantation due to his age and severe emphysema.

-lar" received the 5arvi"6 artificial heart, the product of several decades of research [].



The early 5arvi"6 Total 'rtificial 7eart []

The 5arvi"6 artificial heart was the first artificial heart

successfully transplanted into a human being []. This

device was constructed out of aluminum and polyurethane

and was powered by an almost 4!! pound refrigerator si2ed air compressor. -lar" had a vast number of medical

issues during the 11 days he was "ept alive with the

5arvi"6. These included sei2ures, a coma, malfunctioning

valves, renal failure, and pneumonia. 7owever, on the11th day with the 5arvi"6 artificial heart, -lar" finally

succumbed to multi6organ failure [].

These early versions are a far cry from the modern-ardio8est and 'bio-or artificial hearts.

A( 4ardio5est Artificial Heart#

The -ardio8est 'rtificial 7eart was tested in many

patients in a study conducted as a trial through the 9$'[]. This study included 1! patients, 31 meeting protocol

standards, + controls, and 14 patients who did not meet

inclusion criteria but received the device due on a

compassionate use basis [].

't the conclusion of this study it was found that *% of

patients receiving the total artificial heart survived to

cardiac transplantation, compared to only 40% of thecontrol group []. The effectiveness of the -ardio8est

artificial heart in improving the :uality of life of patients

was also evaluated. Of those receiving the artificial heart,

!% survived to one year after transplantation. This iscompared to the only !% of patients whom survived to

one year after transplantation in the control group [].

The :uality of life for patients receiving the total artificialheart during the bridge to cardiac transplantation also was

significantly higher than that of patients in the control

group []. One wee" after the implantation of the artificial

heart, +% of patients in the protocol group were out of bed. 0!.+% of these patients were mobile, able to wal" at

least 1!! ft. [].

7owever, there were also a considerable amount of

complications with this artificial heart during the trial.$uring the course of the trial, there were 1! bleeding

events, one serious device malfunction, and a fittingcomplication with the device on five patients []. This

misfitting of the device contributed to the death of two out

of the five patients, while the serious device malfunction

was the cause of death for one patient. 'lso during thecourse of the trial there were 1+ infections [].The modern -ardio8est artificial heart [].



This data can be accounted for, however. ;n 34% of the

patients receiving the device, infection was not a

contributor to transplantation delay or death []. The

study also contends that, <'s e#pected in this group of very sic" patients, most of the deaths before

transplantation were due to end stage heart disease,

whereas most deaths in the protocol group were related to

multi6organ failure, technical problems, sepsis, or bleeding during the first four wee"s of transplantation=

[].

The -ardio8est artificial heart eliminates many problemscommonly seen with the &'$ devices according to 5ac"

-opeland in the article, <-ardiac >eplacement with a

Total 'rtificial 7eart as a ridge to Transplantation=. 7e

states, <The -ardio8est Total 'rtificial 7eartorthotopically replaces both native cardiac ventricles and

all cardiac valves, thus eliminating problems commonly

seen in the bridge to transplantation with left ventricle and

biventricular assist devices, such as right heart failure,

valvular regurgitation, cardiac arrhythmias, ventricular clots, intraventricular communications, and low blood

flow= [].

There are also many personal accounts of the success of

the -ardio8est artificial heart. 5ustin >yder was only +

years old by the time he was in desperate need of hearttransplantation [4]. >yder was born with an enlarged heart

and went through several surgeries including artificial

mitral and aortic valves, a pacema"er, and a defibrillator.

'fter a test of his heart revealed that his e#isting heartwas incredibly inefficient, >yder was put on the transplant

list [4].

$uring the bridge to cardiac transplantation, >yder hasthe -ardio8est artificial heart implanted [4]. 8ithin two

wee"s of receiving the artificial heart, >yder was healthy

enough to be placed on the 9reedom portable driver

power source for his heart. >yder said of his 3 days withthe -ardio8est artificial heart, <; played bas"etball, ;

played soccer with the 9reedom driver, ?ust wearing it in a

bac"pac", and never had any problems. ;t@s a no brainer.

;f you have to ma"e the decision to receive the Total'rtificial 7eart, if that@s your only decision to stay alive, ;

don@t even "now why you@d hesitate to say yes= [4].

The -ardio8est artificial heart was successful both in the

clinical trial as well as with 5ustin >yder. The -ardio8estartificial heart is a practical solution for individuals during

the bridge to heart transplantation because of the low

number of complications and high number of successesconsidering that most patients receiving the treatment

were already in end6stage heart failure.

B( A"io4or Total Artificial Heart#

One of the most innovative artificial hearts is the 'bio-or

'rtificial 7eart manufactured by 'bioAed [+]. The

'bio-or artificial heart is considered so innovative because it is the first fully implantable artificial heart.

8ith the 'bio-or, the patient is not attached to monitors,

e#ternal pumps, or other controls. i"e the -ardio8est

artificial heart, the 'bio-or heart fully replaces bothventricles of the heart while attaching to the patients

natural atria. 7owever, patients with the 'bio-or artificial

heart have more freedom than those with other artificial

devices. The 'bio-or is powered through an e#ternal power source but also has an internal power source that is

implanted into the patient@s abdomen. This allows patients!64! minutes at a time off of the e#ternal battery to

perform natural daily activities such as showering [+].

8hile the 'bio-or allows patients more freedom, it also

helps to decrease infections [+]. The 'bio-or does re:uirean opening in the patient@s body to receive power. The

'bio-or receives power through a radio signal

transmitted from the battery pac" to give the internal

power source energy. This is crucial according to 9redBarenetchi, president of 'bioAed. 7e contends, <8hen

you implant a cable that runs outside the body, there is an

easy pathway for serious, deep infection= [+].

This is true of many other devices such as the &'$ as

well as the -ardio8est artificial heart. ;n the -ardio8est

artificial heart, *% of patients in the protocol group had

transplant delay or died as a result of infections sustainedfrom the power source [].

'nother advantage of the 'bio-or artificial heart over

&'$s is the e#ceptionally slic" surface of the device [+].Thromboembolism is :uite a common problem with

The modern 'biocor 'rtificial 7eart [+].



&'$ devices. 7owever, 'bioAed@s artificial heart is

made of a material that clots cannot stic" to [0].

The 'bioAed has applied for ./. 9ood and $rug'dministration (9$') approval to allow for the sale of

'bio-or to the public [+]. 7owever, 'bio-or is currently

undergoing clinical trials. The 'bio-or has been

implanted in a total of 1+ patients. Of these patients, thelongest living lived 1 months on the device before his

death due to an internal membrane wearing out on the

device [+].

;t is the hope of 'bioAed to use the information gathered

from their clinical trials to produce an artificial heart that

can be used for five years before replacement.

;t appears that the 'bio-or and devices li"e it are the

future of the bridge to cardiac transplantation. The

'bio-or has advantages over the -ardio8est due to itsdurability, strength, and its resistance to

thromboembolism and infections.

III( Oran 4are S!ste%s

;n 1*0, the first organ transplant too" place [0]. /ince

that time, there has been no change in how organs are

cared for in the time they are ta"en from the donor and put into the recipient.

's simple as it may seem, this process involves a cooler and ice. This system, while :uite effective, can only "eep

an organ viable for a ma#imum of si# hours. 'fter this

point, the organ is considered too dangerous to transplant

into a human being [1].

This is a significant contributor to the length of the bridge

to cardiac transplantation in the nited /tates. 'lthough

the ./. population currently stands at 1.*1 millionaccording to the ./. -ensus ureau, only !!! donor

hearts are received by patients [0]. This is due to the vast

number of organs that go unused due to geographic

restraints [1]. ;n 7awaii alone, almost 4! usable hearts gounused per year due to the time it ta"es to travel the

distance from 7awaii to the mainland of the nited /tates

[1]. 8ithout a significant change in the transportation of

donor organs the situation is only going to get worse. Thisis due to an overwhelming amount of the

./. population, 1 percent, beingconsidered baby boomers [0]. These

individuals are aging :uic"ly and will soon be re:uiring avast number of donor organs. The solution to this problem

lies in two new technologies, the &aso8ave and the

Transmedics Organ -are /ystem (O-/).

A( 6aso5a&e

The &aso8ave organ care system is a machine that puts

the donor organ into an environment very close to the

natural physiological state in the body. This process

essentially preserves the organ instead of slowing thedeterioration of the organ li"e the ice and cooler method

does [].

'ccording to $r. 5ohn >obertson, the chief science officer and e#pert in transitional medical problem solving, the

&aso8ave does ?ust that. 7e stated, <8e can demonstrate

very effective fluid circulation down to the level of tiny

capillaries, the place where cells interface with thecirculation. 8e have demonstrated that a uni:ue pulse

waveform helps create better transplants C ones more

li"ely to wor" and to continue to wor".= The ability to

continue to transplant fluid to the tissues coulde#ponentially increase the life of an organ by increasing

the circulation. This increase in the circulation of blood

and other fluids to an organ creates a healthier organ and a

better transplant for the patient [].

'nother interesting aspect of the &asowave system is its

fle#ibility. The &asowave has the capability to "eeporgans as diverse as a pediatric "idney to a full6si2e adult

liver alive in the bridge to transplantation [].

'lthough cutting edge, the &asowave has not had muchtesting or clinical trials to substantiate any claims made.

'ccording to their website, <&asowave is an investigative

device in the preclinical stage of development. The

&asowave has yet to be e#tensively tested on humans or approved for commercial sale by the 9$' or any other

governing body= [3].

B( Trans7edics Oran 4are S!ste%

TheTransAedics

Organ -are /ystem (O-/) is a device similar to the

&aso8ave system in that it is used to preserve organs by

"eeping them in a near physiologic state. The entire O-/system is about ! pounds, and the si2e of a miniature

refrigerator.

The cutting6edge TransAedics Organ -are /ystem [3].

The heart is contained in the O-/ perfusion chamber.



Once the organ is removed from the body, it is placed in

the perfusion chamber of the O-/ (shown in the photo

above) [3]. Then, tubes are placed into the organ which

helps it to circulate 1,!!!61,+!! ml of the donors@ blood.The blood is fed nutrients including amino acids and

glucose to "eep it fresh. Therefore, the heart may remain

pumping blood as it normally would inside the human

body. The TransAedics -ompany claims that the O-/can "eep an organ transplantable for up to 1 hours,

which would help to get viable hearts to a significantly

larger number of individuals in need [3].

The O-/ has substantially more clinical trials and testing

than the cutting edge &aso8ave organ care system. The

O-/ was tested in a trial in Durope to test its@ durability

and safety for humans [3]. Twenty heart failure patientswere given a donor organ "ept viable and transported by

the O-/ system. The trial concluded that 1!! percent of

patients were still living ! days after transplantation [3].

nfortunately, the O-/ is not yet available in the nited/tates and has not been 9$' approved. The O-/ is

currently in the process of a clinical trial with the 9$' on! patients in the nited /tates to determine the safety

and reliability of the O-/ for future organ transplantation

[3].

I6( 4onclusion

Technology to aid patients in the bridge to cardiac

transplantation has developed substantially over the last! years. $evelopments have been made to not only help

patients survive to heart transplantation, but to help donor

organs survive longer as well.

'lthough significant developments have been made to

ma"e artificial hearts a reliable option for even the sic"est

of patients, it is not enough. 9urther technologies need to

be developed which can "eep patients alive much longer than a year. 8ith the rise in the aging population e#pected

very soon, we need a permanent solution for the shortage

of transplant hearts. 8hile the 'bio-or and the

-ardio8est are a step in the correct direction, they needto develop durability. These devices could also benefit

from a decrease in complications from the devices

themselves, or an easy way to replace the devices or partsof the devices.

8hile organ care systems such as the TransAedics O-/

and the &aso8ave have not been approved yet for use in

the nited /tates, they could drastically ma"e an impact

on the face of organ transplantation. These systems candouble the life of the organ outside of the human body

while "eeping the organ healthier, but organ longevity out

of the body is still a challenge. 9uture developments in

the field of organ transplant machines such as theseshould focus on "eeping the organ living for a much

longer period of time than they are currently achieving.

The bridge to cardiac transplantation is a long andstressful time for those waiting for a transplant. 7owever,

devices li"e the artificial heart and devices to increase the

longevity of donor organs are helping not only to shorten

this bridge, but provide a better :uality of life for patientsand their families. ;t is through the further development of

technologies such as these that the bridge to cardiac

transplantation will be a much safer and shorter time for

citi2ens of the nited /tates.

References#

1. Heart In A Box. Eerf. 'bbas 'drehali. F.D. 9ocus9orward, !1. Online.

. 5auhar, /andeep, A$, Eh$. GThe 'rtificial 7eart.G The New England Journal of Medicine +!.0 (!!4)H +464. ProQuest Psychology Journals. 8eb. Aar. !14.

. -opeland, 5ac" F., >ichard F. /mith, 9rancisco '.'rabia, Eaul D. Iolan, Fulshan J. /ethi, Eei 7. Tsau,$ouglas Acclellan, and Aarvin 5. /lepian. G-ardiac>eplacement with a Total 'rtificial 7eart as a ridge to

Transplantation.G New England Journal of Medicine+1.* (!!4)H 3+*60. Erint.

4. G/yn-ardia /ays ;ts Total 'rtificial 7eart Offers ridgeto 7eart Transplant Eatients.G Entertainment lose ! "#(!1)H n. pag. ProQuest Business ollection. 8eb. Aar. !14.

+. Dhrenman, Fayle. G' 8hole Iew 7eart.G Mechanical Engineering 1+.3 (!!)H +16+. ProQuest Businessollection. 8eb. Aar. !14.

0. G-ensus ureau Eopulation.G "$%$ ensus Bureau. I.p., n.d. 8eb. + Aar. !14.

. G&'/O8'&DK /ystems.G &rgan Trans#lant Technology' %mart Perfusion (aso)a*e %ystem' +i*er Trans#lant' ,idney Trans#lant' Heart Trans#lant .&aso8ave, n.d. 8eb. Aar. !14.

3. Leter, >uhi, Aichael 7ubler, Airalem Easic, >oland7et2er, and -hristoph Jnosalla. GOrgan Ereservation withthe Organ -are /ystem.G A##lied ardio#ulmonary

Patho#hysiology 1+ (!11)H !61. A##lied



ardio#ulmonary Patho#hysiology. Eabst /cienceEublishers, !11. 8eb. Aar. !14.

Biora$hical S/etch#

5essica Burcher is currently a freshman iomedicalDngineering student at ;ndiana ;nstitute of Technology.

/he is pursuing her achelors in iomedical Dngineeringand plans to eventually attend medical school to become a

pediatric cardiologist.

5essica has been the recipient of the $ean@s ist honorsthe fall semester. /he is also heavily involved in her university where she is a member of the &arsity 8omen@s/occer Team, iomedical Dngineering /ociety, and willserve as a >esident 'ssistant ne#t fall.

advancements in artificial hearts

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