Advancements in Artificial Hearts
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Transcript of Advancements in Artificial Hearts
8/18/2019 Advancements in Artificial Hearts
http://slidepdf.com/reader/full/advancements-in-artificial-hearts 1/6
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 $ecember 1, 1*3 [].The man, named arney -lar", was ineligible for heart
transplantation due to his age and severe emphysema.
-lar" received the 5arvi"6 artificial heart, the product of several decades of research [].
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The early 5arvi"6 Total 'rtificial 7eart []
The 5arvi"6 artificial heart was the first artificial heart
successfully transplanted into a human being []. This
device was constructed out of aluminum and polyurethane
and was powered by an almost 4!! pound refrigerator si2ed air compressor. -lar" had a vast number of medical
issues during the 11 days he was "ept alive with the
5arvi"6. These included sei2ures, a coma, malfunctioning
valves, renal failure, and pneumonia. 7owever, on the11th day with the 5arvi"6 artificial heart, -lar" finally
succumbed to multi6organ failure [].
These early versions are a far cry from the modern-ardio8est and 'bio-or artificial hearts.
A( 4ardio5est Artificial Heart#
The -ardio8est 'rtificial 7eart was tested in many
patients in a study conducted as a trial through the 9$'[]. 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.$uring the course of the trial, there were 1! bleeding
events, one serious device malfunction, and a fittingcomplication with the device on five patients []. This
misfitting of the device contributed to the death of two out
of the five patients, while the serious device malfunction
was the cause of death for one patient. 'lso during thecourse of the trial there were 1+ infections [].The modern -ardio8est artificial heart [].
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This data can be accounted for, however. ;n 34% of the
patients receiving the device, infection was not a
contributor to transplantation delay or death []. The
study also contends that, <'s e#pected in this group of very sic" patients, most of the deaths before
transplantation were due to end stage heart disease,
whereas most deaths in the protocol group were related to
multi6organ failure, technical problems, sepsis, or bleeding during the first four wee"s of transplantation=
[].
The -ardio8est artificial heart eliminates many problemscommonly seen with the &'$ 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
&'$s is the e#ceptionally slic" surface of the device [+].Thromboembolism is :uite a common problem with
The modern 'biocor 'rtificial 7eart [+].
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&'$ 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.
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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
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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.