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Journal of Cardiovascular NursingVol. 20, No. 5S, pp S22–S30 ❘ ©
2005 Lippincott Williams & Wilkins, Inc.
Julie A. Shinn, MA, RN, CCRN, FAANStanford University Medical
Center, Stanford Hospital and Clinics,Calif.
Corresponding authorJulie A. Shinn, MA, RN, CCRN, FAAN, Stanford
University MedicalCenter, Stanford Hospital and Clinics, Room H0105
MC 5221, 300Pasteur Dr, Stanford, CA 94305 (e-mail:
[email protected]).
Implantable LeftVentricular Assist DevicesJulie A. Shinn, MA,
RN, CCRN, FAAN
The first bridge to transplant with a left ventricular assist
device (LVAD) was preformed over 20 years ago. Since that time, the
devices have continued to evolve and now patients arebeing
supported with devices as an alternative to transplantation. The
primary indication ofend-stage heart failure remains the same but
increased knowledge about patient selection, thetiming of implant,
and patient management have contributed to improved outcomes
withdecreasing adverse events. Multiorgan failure, right
ventricular failure, bleeding, infection,thromboembolism, and
device malfunction continue to be the most serious threats to
long-term survival in these patients. Despite that, patients who do
well are now able to bedischarged from the hospital and resume
relatively normal lives with the devices. The articlereviews 3 of
the most widely used LVADs for bridge to transplant therapy: the
Thoratec;HeartMate vented electric; and the Novacor Left
Ventricular Assist System. Indications,mechanism of operation,
clinical problems, and out-of-hospital preparation are
outlined.
KEY WORDS: alternative to transplantation, heart failure,
ventricular assist devices
Considerable progress has been made in the lastdecade in
treatment of congestive heart failure.Newer pharmacologic agents,
biventricular pacing,and implantable defibrillators have enabled
cardiolo-gists with the ability to maintain patients in a
com-pensated state with good quality of life for long peri-ods of
time. Surgical techniques of revascularization,valve repair, or
replacement and surgical remodelingof the left ventricle also have
extended the lives ofmany patients. Despite these advances, the
5-yearmortality rate for heart failure continues to be about70%.1
Approximately 5 million Americans haveheart failure today and after
the age of 65 years, itaffects approximately 10 per 1000 of the
population.1
Heart failure is the cause of approximately 250,000deaths per
year in the United States.2 As heart failureprogresses and becomes
more refractory to treatment,subsequent secondary organ dysfunction
develops asa result of chronic poor organ perfusion. At this
end
stage of the clinical syndrome of heart failure, there isa
1-year mortality of more than 50%.3
Heart transplantation is a treatment option formany end-stage
heart failure patients but with donorsupply limited to
approximately 2500 organs per year,it is clearly not an option for
most patients.4 Youngerpatients without comorbidities are the most
likely can-didates for heart transplantation. They are also
thebest-suited candidates for left ventricular assist device(LVAD)
implantation as a bridge to transplantation.The use of LVADs as
bridges to transplantation hasbecome a standard treatment option
for advancedheart failure. Between January 2002 and May 2004,312
patients in the International Society for Heart andLung
Transplantation’s (ISHLT’s) Mechanical Circul-atory Support
Database received bridge to transplanttherapy in 48 centers
submitting data5; 35 of those cen-ters were in the United States.
This number is actuallyan underestimate of all LVAD patients being
bridged totransplant as the database is still relatively new
andmany centers have yet to enroll.
The goal of most companies that are developingLVAD devices is to
develop products that can serve aspermanent, definitive therapy.
The HeartMate ventedelectric (VE) system (Thoratec, Pleasanton,
Calif) wasapproved for this use by the Federal Food and
DrugAdministration (FDA) for destination therapy in
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Implantable Left Ventricular Assist Devices S23
2003 and the Novacor Left Ventricular Assist System(LVAS) (World
Heart, Oakland, Calif) is in the finalstages of an evaluation study
for premarket approval.It is estimated that 30,000 to 60,000
end-stage heartfailure patients in the United States per year would
bepotential candidates for destination therapy.6
The article reviews the clinical indications, clinicalproblems,
and out-of-hospital preparation of the 3most widely used LVADs as
bridges to transplantationtherapy: the Thoratec; HeartMate VE, XVE
(a newerrevision of the VE); and Novacor LVAS devices.
Historical PerspectiveThe first successful bridge to heart
transplant with animplantable LVAD was done in 1984 with a
NovacorLVAD.7 That patient lived more than 20 years
aftertransplantation. Many lives have been saved by thistechnology
but it has been difficult to determine whothe best candidates are
and who has the greatestchances of survival. Because of the
relatively low vol-ume of patients, no one center where LVAD
implantsare performed can amass enough data to answer thatquestion
well. For that reason, in 2001, a mechanicalcirculatory support
device database was establishedby the ISHLT to collect and pool
data from multipleinstitutions. The goal of this project is to
accuratelyanalyze data to help improve short- and long-termoutcomes
and to facilitate the selection of patientsbest suited for this
therapy.5 The majority of thepatients who have been entered in the
databasereceived LVADs capable of chronic support.
A significant study opened the door for theexpanded use of
implantable LVADs as an alternativeto transplantation. The
Randomized Evaluation ofMechanical Assistance for the Treatment of
CongestiveHeart Failure (REMATCH) was a randomized, con-trolled
trial of 129 patients in 20 institutions who wereineligible
candidates for heart transplantation. Ofthose, 68 were randomized
to receive the HeartMateVE LVAD and 61 patients served as controls,
receivingoptimal medical management.8 The importance of thestudy
was the demonstration that LVAD implants wereassociated with a
relative reduction in the risk of deathof 48% during the entire
follow-up period comparedto the medical therapy group (P � .001).8
This studyled to the FDA approval of the device for use as
desti-nation therapy in November 2002. Subsequent to that,the
Centers for Medicare and Medicaid Services (CMS)approved national
insurance coverage for destinationtherapy in October 2003.
Indications for LVAD TherapyThe primary indication for LVAD
therapy is end-stage heart failure that is no longer responding
to
conventional medical management. If the implant isfor bridge to
transplant, the patient would berequired to meet transplant
criteria and to already beaccepted as a transplant candidate.
Patient selectionis extremely important determinant of patient
out-come following LVAD implant.9,10 Prior to implant,the majority
of patients will be hospitalized on intra-venous inotropic therapy.
Many will require the sup-port of intra-aortic balloon pump
therapy, althoughsome centers do ventricular assist device
(VAD)implantation without a trial on intra-aortic balloonpump
therapy. It is important to time surgery beforerenal and hepatic
dysfunction deteriorate and beforepostoperative right ventricular
failure will become asignificant problem.10
The best outcomes will be achieved in patientsgoing for implant
under elective conditions.Emergency implant is associated with
higher mortal-ity.11 Investigators at Columbia University have
cal-culated a risk factor score that can be used to predictoutcomes
after device implant.12 They identified sev-eral risk factors that
place patients at greater risk ofmortality in a consecutive series
of 130 patients.Each factor carries a weighted score and a total
scoreof more than 5 corresponded to 47% mortality com-pared to 12%
mortality in patients with scores ofless than 5. Risk factors
included mechanical ventila-tion, previous LVAD, or right
ventricular assistdevice used as a bridge to a more long-term
VAD,postcardiotomy shock, previous cardiac surgery, acentral venous
pressure more than 16 mm Hg as anindicator of the extent of right
ventricular failure, aprothrombin time more than 16 seconds,
acutemyocardial infarction, and ischemic cardiomyopa-thy.12 The
single most important risk factor for mor-tality after LVAD implant
is the presence of preoper-ative mechanical ventilation.12 Table 1
summarizesthe risk factors for mortality. At present, no univer-sal
criteria exist and patient selection remains a com-plex
process.13
Overview of the DevicesThis review cannot possibly outline in
detail all of theLVAD devices being used and evaluated today.
Manyhave merits but are still in investigational stages requir-ing
FDA approval for use in selected centers. Thisreview will focus on
3 devices that are used widely andhave FDA approval for bridge to
transplantation.
Thoratec LVAD
The Thoratec LVAD is an external, paracorporeal,pulsatile
pneumatic pump. Its placement is achievedvia a median sternotomy on
cardiopulmonary bypass.The inflow cannula is placed in the left
ventricular
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S24 Journal of Cardiovascular Nursing ❘ September/October
2005
apex and tunneled subcostally to the external pump.Blood is
returned via an outflow cannula, again, sub-costally to the
ascending aorta. The inflow cannulacan also be placed in the left
atrium but less optimalflows will be a disadvantage and that is not
the usualapproach if the patient is being bridged to
transplant.Figure 1 illustrates the placement of this pump.
Theblood sac is a smooth, polyurethane material, whichwill
necessitate that the patient be anticoagulated ini-tially with
heparin and later converted to warfarinsodium. A console or the
driver of the pump is con-nected via a pneumatic hose that will
deliver alter-nating pressure or vacuum inside the rigid shell
hous-ing the blood sac. With pressure, the blood sac col-lapses,
causing ejection to occur. Application of vac-uum creates a
pressure gradient assisting filling fromthe left ventricle.
Unidirectional flow is maintainedby tilting disk valves in the
blood pump. The maxi-mum stroke volume of this pump is 65
millimeters.Its flow or output will depend on how quickly thepump
fills. Pump flow rates range from 1.3 to 7.2mm per minute.14
The cannula to and from the pump are coveredwith a Dacron
material that allows for endothelialcell ingrowth, which
effectively seals off the tract ofthe cannula into the mediastinum,
preventing migra-tion of bacteria from the skin into the
mediastinum.This act of sealing also allows the patient
consider-able mobility after this process is complete. It
usuallytakes up to 10 days for sealing to be completed.
An obvious advantage of this pump is that it canbe placed in
smaller individuals such as women oradolescents. Its paracorporeal
position does notrequire the larger body habitus needed for the
totallyimplantable LVADs. This pump requires a body sur-face area
of 1.3 m squared versus the totallyimplantable pumps, which require
a body surfacearea of 1.5 meters squared. Another advantage of
thesystem is that a second pump can easily be added tosupport the
right ventricle when indicated.
Two modes of operation are commonly used withthis pump. It can
be run at a fixed rate determined byclinicians or in an automatic
mode. The automaticmode operates by activation of a switch
signaling afull blood sac. This switch initiates the filling of
thepump housing with compressed air, which forces theblood out of
the blood sac, and ejection commences.When ejection is complete,
vacuum is applied andfilling of the blood sac begins. Fill to empty
is a termthat is used to describe this method of operation.
Thepreferred trigger for pump ejection is when the pumpreaches full
fill. It can be run at a fixed rate, but it ispreferred to have the
blood sac fully fill to prevent thepossibility of thrombus
formation with in the bloodsac. Any LVAD that operates in such a
method will beasynchronous with the native heart rate and
willincrease or decrease its rate on the basis of the rate
offilling. In this way, the pump rate can increase toaccommodate
the patient’s activity level and increasedrate of venous return to
the heart. Pump rates typi-cally decrease when the patient is at
rest. Any pumpusing a fill to empty mode will be totally
dependenton the patient’s preload status for adequate pumpoutput
and support of systemic circulation.
Although the Thoratec pump is pneumatic, elec-trical power must
be available at all times to run thecompressors. A portable console
that can run thepump on battery power is available. Each
fullycharged battery with the portable console can sup-port a
patient on an LVAD for up to 80 minutes.With a pneumatic system,
ventricular assist can bemaintained utilizing manual pumping to
compressthe blood sack in the event of a console
malfunction.Patients being maintained on the portable systemcan be
discharged from the hospital to wait fororgan donation. The
Thoratec VAD system wasapproved for use as a bridge to transplant
device in1995.14
TABLE 1 Risk Factors for Mortality After LVADImplant*
■ Mechanical ventilation■ Previous LVAD or RVAD used to bridge
to a long-term VAD■ Postcardiotomy shock■ Redo surgery■ CVP � 16 mm
Hg■ Prothrombin time � 16 s■ Ischemic cardiomyopathy
*LVAD indicates left ventricular assist device; RVAD, right
ventricularassist device; VAD, ventricular assist device, and CVP,
central venouspressure.
FIGURE 1. Placement of the Thoratec left ventricular
assistdevice is illustrated depicting the paracorporeal
placementwith the pump outside the body and with the inflow
andoutflow cannula traversing subcostally to the left ventricleand
ascending aorta respectively. This is an example ofbiventricular
support. Reprinted with permission fromThoratec Corp, Pleasanton,
Calif.
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Implantable Left Ventricular Assist Devices S25
A newer version of this pump is the ThoratecInternal Ventricular
Assist Device (IVAD), which is asmaller version of the same pump,
allowing it to beimplantable. A wire for the electrical signal of
“full fill”and the pneumatic hose remains external. The princi-ples
of pump operation are the same. The advantagesare increased patient
mobility, esthetics, and the reim-bursement category for implanted
pumps. Also, theesthetics of living outside the hospital with
animplanted pump is more appealing. This particularpump was
approved for use by the FDA in August2004.
HeartMate VE and XVE Pump
The HeartMate VE or XVE is a totally implantableelectrically
driven pulsatile LVAD. The pump is mostoften positioned
preperitionally in the left upperabdominal quadrant or
alternatively intraabdomi-nally. Implantation requires a median
sternotomythat extends to the umbilicus and the use of
car-diopulmonary bypass. This 2-compartment surgeryincreases the
risk of infection, which is greater in thiscase than when the
device is isolated to the chestcavity alone. The pump is made of
medical gradetitanium. The inflow cannula is positioned in theapex
of the left ventricle, bringing blood into thepump. Blood is
returned to the ascending aorta fromthe outflow cannula of the
pump. Constructedporcine tissue valves maintain unidirectional
flow. Apercutaneous lead from the pump is tunneled subcu-taneously
to exit the body in the right upper quad-rant just above waist
level. The lead carries electricalenergy to the pump and brings
data from transducerslocated in the pump, alerting clinicians or
the patientto changes in pump rate, stroke volume, or pumpoutput.
This pump has a flow rate capability inexcess of 10 liters per
minute.15
As the pump fills, air must be displaced from thepump housing to
the outside and must reenter as airspace is created during pump
ejection. The air ventthat facilitates these maneuvers can also be
attachedto a hand pump for emergency manual pumping ifthe
electrical mechanism fails. If the situation is unre-pairable,
these pumps can be converted to pneumat-ically driven systems
requiring that dischargedpatients be readmitted to the hospital.
Figure 2 illus-trates the design and positioning of the HeartMateVE
LVAD. Figure 3 is a picture of both the Thoratecand HeartMate
Pumps.
HeartMate’s percutaneous lead is covered with aDacron material
that will allow for tissue ingrowththat, when intact, will protect
the patient from infec-tion. The lead is connected to a system
controller,which runs and monitors the pump for alarm condi-tions.
The controller is attached to a source of AC
power or 2 portable lead acid batteries that are capa-ble of 4
to 6 hours of untethered support. Controllerscan be clipped to a
belt and batteries can be carriedin a shoulder holster or waist
pack. External compo-nents are relatively light weight, which
allows thepatient a broader range of activities than the
Thoratecpump.
FIGURE 3. Thoratec and HeartMate sites.
FIGURE 2. This illustration depicts the implantableHeartMate
pump with the wearable controller and battery.Reprinted with
permission from Thoratec Corp, Pleasan-tation, Calif.
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S26 Journal of Cardiovascular Nursing ❘ September/October
2005
As with the Thoratec, the HeartMate can either beoperated at a
fixed rate or in the automatic mode inwhich ejection occurs when
the pump is fully filled.Pump rates in the automatic mode are
determined byhow quickly the blood pump is filled by the left
ven-tricle. A unique characteristic of the HeartMate is thetextured
interior surface of the blood pump thatencourages endothelial cells
to cover the surface cre-ating a biologic lining. As a result of
this smooth bio-logic lining interfacing with the blood, patients
donot need to be maintained on warfarin for anticoag-ulation as do
all other with LVAD devices. Antiplatelettherapy is all that is
required.16
Novacor LVAS
Like the HeartMate, the Novacor pump is animplantable,
electrically driven, pulsatile LVAD. It isone of the most reliable
systems of circulatory sup-port.17 In fact, it comes with a 3-year
warranty andit is the only pump to offer such a warranty. Long-term
support capability has been demonstrated. ByKaplan-Meier analysis,
excluding percutaneous leaddamage, more than 86% of pumps are in
service at 3 years.18 With long-term use, eventual wearing
ofmechanical parts and the porcine tissue valves canoccur,
requiring elective replacement. In 10 patientswho have lived longer
than 3 years on pump support,3 patients required pump
replacement.18 TheNovacor is still in the process of acquiring
FDAapproval for destination therapy use in the UnitedStates. The
positioning of the pump in the left upperquadrant of the abdomen is
similar to the techniqueof the HeartMate VE placement with the same
con-nections to the left ventricle and aorta. A percuta-neous lead
is also used to bring electrical power tothe pump, to send
hemodynamic information fromthe pump to the system monitor and to
provide aroute for airflow in and out of the pump housing.Figure 4
illustrates the Novacor pump placement.Pump flow rates of 10 liters
per minute are achiev-able with this LVAD.
Modes of operation are similar to the HeartMate aswell. It can
either be programmed to run in a fixedrate mode or in a fill to
empty mode. The rate of bloodfilling the pump determines when
ejection occurs inthe later mode. When it is set to trigger when
fillingdecreases by 100%, it runs in fill to empty mode.
Thatpercentage can be decreased to allow for synchroniza-tion with
the native heart systole. In a bridge to trans-plant patient or
eventually a destination therapypatient, that feature is not
necessary. It might be usedin a patient who might potentially be
weaned from thepump. Explantation of LVADs following
myocardialrecovery after LVAD support has been reported insmall
numbers of patients.19–21
The Novacor pump is currently being evaluated asa destination
therapy device under an FDA con-trolled trial. The trial,
Investigation of Non-Transplant Eligible Patients who are
InotropeDependent or INTrEPID, is completed but the resultsare yet
to be released.
Unlike HeartMate, the Novacor requires antico-agulation with
heparin initially followed by conver-sion to warfarin sodium. In
addition, antiplateletagents are required to prevent thrombotic
events andtransient ischemic phenomena. These events are mostlikely
to occur in the first 30 days postimplant.17
Initially, stroke was a greater problem in the NovacorLVAS but
modifications in the outflow graft havebeen made. As a result, the
incidence of these adverseevents is similar in both pumps.17
Like the HeartMate pump, the batteries and con-troller can be
carried or worn by the patient. Patientscan be untethered from AC
power for up to 5 hoursper battery. Battery support duration is
only limitedby the number of charged batteries a patient has inhis
or her possession.
ComplicationsThere are several postoperative complications to
bevigilant for and are seen in all of the previously
FIGURE 4. An implanted Novacor left ventricular assistdevice is
depicted showing pump placement and the wear-able controller and
batteries. Reprinted with permissionfrom World Heart, Inc, Oakland,
Calif.
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Implantable Left Ventricular Assist Devices S27
described LVAD populations. The causes of deathfollowing device
implant are primarily multiorganfailure, renal failure, right
ventricular failure, andinfection.10 Bleeding and thrombembolism
are 2other important complications causing postoperativemorbidity.
Patient selection and timing of the deviceimplantation appear to be
critical factors that deter-mine successful outcome.10 As data on
complicationsand patient characteristics accumulate, risk
factorsfor these complications will be better understood
andoutcomes should improve over time.
Multiorgan Failure
Patients with end-stage heart failure have many pre-operative
conditions that may contribute to the devel-opment of multiorgan
failure postoperatively.Preoperative low perfusion may be evident
and maypersist postoperatively after the insult of cardiopul-monary
bypass and the surgery itself. Preoperatively,patients may be
supported with mechanical ventila-tion and may already have some
degree of pulmonarydysfunction. Often, creatinine, blood urea
nitrogen,and bilirubin levels are elevated, suggesting renal
andhepatic dysfunction. Nutrition is often inadequateand is very
likely an underestimated risk factor inmechanical support.10 The
more severe the level ofsecondary organ dysfunction is
preoperatively, thegreater the risk of postoperative multiorgan
failure.Multiorgan failure accounted for 27% of deathsreported to
the ISHLT circulatory support database.5
Right Ventricular Failure
Right ventricular failure is a concern in any patientwho has
elevated pulmonary and central venous pres-sures in the
preoperative setting. The hallmark of rightventricular failure in
the postoperative period will beelevated central venous pressures,
an empty left ventri-cle, and a decrease in device outputs.15 These
patientswill require right ventricular unloading with vasodila-tors
and/or nitric oxide and prolonged inotropic sup-port of the right
ventricle. Given time, the right ventri-cle usually recovers as
left sided unloading remainsconstant with the assist of the LVAD.
An occasionalpatient may require temporary assist from a
short-termright ventricular assist device. Continual
biventricularsupport might be employed in a bridge to
transplantpatient with either the implanted or
paracorporealThoratec but this would not be a suitable option for
adestination therapy patient. That type of patient wouldneed to
utilize a temporary support device.
Bleeding
Postoperative bleeding is common and there aremany factors that
contribute. Prolonged cardiopul-
monary bypass time, anticoagulation, and extensivesurgical
dissection, especially with the Heartmate VEand Novacor, will
contribute to increased risk ofbleeding. Preoperative hepatic
dysfunction will alsoadd to the risk of coagulopathy. Patients who
havehad previous cardiac surgical interventions will bemore prone
to bleeding because of excessive scarringin the mediastinum and the
need for more surgicaldissection. Excessive bleeding has been as
frequent as20% and 50% with the Thoratec, HeartMate, andNovacor
devices but has decreased with greaterdevice experience.15 The
ISHLT database reports a27.8% incidence of postoperative
bleeding.5
Infection
Infection is a serious complication that occurs fre-quently.
Patients are vulnerable to the usual postoper-ative infections seen
in any postsurgical patient suchas line sepsis, pneumonias, and
urinary tract infec-tions.15 These infections may have been present
pre-operatively because of the debilitated nature of thepatients’
conditions. Device-related infections canoccur in the percutaneous
driveline, the pump pocket,from the pump in the form of
endocarditis, or in theblood stream. Percutaneous driveline
infections arethe most common. The most common pathogens
arestaphyloccus, pseudomonas, enterococcus, and can-dida.22 Pocket
infection rates range from 11% to24% for the HeartMate and Novacor
LVADs, witheven greater rates of driveline infections, which
rangefrom 18% to 30%.23 The ISHLT circulatory supportdatabase
reports a 32.5% incidence of infection andthat infection is
responsible for 7% of deaths for alldevices in the database.5
Infection does not present anobstacle to successful transplantation
as long as it isidentified and appropriately treated. In theREMATCH
trial, the probability of infection of theLVAD device was 28%
within 3 months of implantand was the leading cause of death.8 Once
deviceinfection occurs, it can usually be controlled for someperiod
of time but often reoccurs, causing late mor-tality and
morbidity.22
As we enter the era of destination LVAD therapy,device-related
infection is a major concern. In per-manent implants, chronic
infection will decreasequality of life, increase the cost of care,
and mayrequire replacement of the device.24 Along with theusual
practices to prevent infection, steps to preventinoculation of the
pumps and components in theoperating room include limiting room
traffic, avoid-ing opening the LVAD sterile packaging
prematurely,assembling the pump in a low traffic area, usingdummy
pumps to size and fashion the abdominalpockets, using
antibiotic-soaked sponges to covercomponents prior to implant,
using antibiotic
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S28 Journal of Cardiovascular Nursing ❘ September/October
2005
irrigations prior to closure immobilizing the percuta-neous lead
with a secure dressing, and abdominalbinder prior to leaving the
operating room.22
Immobilizing the percutaneous lead, power cables,or drivelines
will be crucial to the healing of the site.Tissue ingrowth into the
velour covering of the leadsor drivelines will take about 10 to 14
days to be com-plete. If the sealing of the track is disrupted by
move-ment or tension on the lead or driveline during thistime, it
may never heal completely. Incomplete heal-ing will allow
microorganisms to be able to track upthe tunneled lead to the pump
pocket or the medi-astinum. Meticulous dressing changes need to be
per-formed daily and their importance emphasized topatients and
caregivers as they begin to assume theirown care.
Thromboembolism
Death from stroke accounts for 10% of all deaths inthe ISHLT
database.5 Neurologic dysfunctionoccurred in 14% of patients.5 All
of these deviceshave a blood-device interface that harbors the
poten-tial for thrombus formation. With the exception ofthe
HeartMate, all of the described devices requireanticoagulation with
warfarin and antiplateletagents. The HeartMate’s biologic lining,
describedearlier, precludes the need for anything other
thanantiplatelet therapy.16 The Novacor device has previ-ously been
associated with higher rates of stroke thanthe other devices.
However, modifications in the out-flow graft have lead to a
thromboembolic rate simi-lar to the HeartMate device.17 A recent
studyreported the incidence of thromboembolic eventsbefore
modifications at 23% compared to an inci-dence of 6% after
modifications.17 In a large multi-center trial of 280 patients
supported with theHeartMate VE, thromboembolic events occurred
in12% of patients; 6% were deemed device related.16
Neurologic impairment following thromboembolicevents range from
transient central nervous system orneuromuscular disorders to
permanent disability.
Device Malfunction
It is not unexpected that some degree of device fail-ure or
malfunction occurs over time with mechanicaldevices. Moving
mechanical parts incur wear. Motorfailure, wear on bearings, wear
on valves, and break-ing of external components because of wear and
tearby patients have all contributed to device failure
andmalfunction. The probability of device failure by 24 months in
the REMATCH trial was 35% requir-ing replacement of the device in
10 patients.8 In thebridge to transplant population at
ColumbiaUniversity, device malfunction that was considered
clinically significant only occurred in 5.7% of thesingle lead
HeartMate VE patients (N � 174), with amean support duration of
65.3 days.25 In a report of277 patients (137 HeartMate VEs, 81
pneumaticHeartMates and 57 Novacors), there were 21 devicefailures
only one of which was a Novacor.26 TheNovacor has demonstrated a
very high degree of reli-ability and durability and impending
wearing out ofthe pump can be diagnosed at least 2 months
beforeanticipated potential failure.11 This wear on pumpswill
become a problem that will need to be furtheraddressed in the
destination therapy patients.
Discharging Patients From the Hospital
Following transfer from the intensive care unit,patients and
caregivers begin training for eventualdischarge from the hospital.
Outpatient care requiresreliable compliance by the patient and
caregiver, con-tinued education with constant reinforcement,
andadequate anticoagulation monitoring.27 Table 2 out-lines
teaching topics unique to LVADs that patientsmust understand and be
competent in before dis-charge can occur. These issues are crucial
because alack of understanding or an inability to demonstrateproper
device management could lead to morbidityand possibly endanger a
patient’s life. It is recom-mended that a teaching documentation
tool with spe-cific competencies be used to track patient and
care-giver progress.28 Patients receive written informationin the
form of patient handbooks from the variouscompanies. Teaching the
patient to become inde-pendent occurs on a daily basis with
instruction byLVAD coordinators and continual reinforcement bythe
unit staff nurses. To reinforce the importance of
TABLE 2 Preparation for Discharge: PatientTraining and Education
Topics Unique to LVADTherapy*
■ Components of the LVAD system and their functions■ Care and
maintenance of the equipment■ Driveline care and dressing changes■
Battery management■ Safety precautions■ Showering techniques■
Response to alarms■ Response to emergencies■ Execution of hand
pumping (Thoratec and HeartMate
only)■ Changing controllers and cables■ Conditions requiring
notification of the physician or device
coordinator■ Anticoagulant monitoring■ Use of the medical center
paging system■ Dealing with household power failures■ Contact with
emergency medical services
*LVAD indicates left ventricular assist device.
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Implantable Left Ventricular Assist Devices S29
what is being taught, some centers use signed con-sents or
contracts to emphasize to the patients andcaregivers the importance
of following the protocolsor instructions.29,30
In preparation for eventual discharge, patients aregradually
introduced to experiences outside the hos-pital. Initially, they
are accompanied outside the hos-pital for various excursions by
professional staff. Asthey become more confident and competent,
they areencouraged to make out-of-hospital excursions
inde-pendently. Some institutions encourage an overnightstay out of
hospital prior to discharge. With dedi-cated, daily teaching and
reinforcement, patientswho do well from a medical point of view and
haveadequate caregiver support can be discharged asearly as 14 days
postimplant.28 Many institutionsrequire that patients reside within
a limited radius ofthe hospital, which is usually a 2-hour drive,
whileother institutions will allow patients to go home evenif that
distance exceeds a 2-hour limit. In this case,the patient and
caregiver must reside locally, demon-strate competence, and have no
outstanding medicalissues before being allowed to live outside a
closeradius to the medical center. It is important that themedical
center personnel advise the patient’s localphysician and emergency
medical personnel of anLVAD patient’s presence in the community.
Trainingand education of these individuals is recommendedin the
event of emergencies in the community.28
These individuals include staff in the local
emergencydepartment, the fire department, and paramedics
andemergency medical technicians who are likely torespond to an
emergency in the home.
As we enter the era of destination therapy, we willsee more
older patients receiving LVAD implantsbecause transplantation is
not an option for them.Older age has some potential impacts on
patient teach-ing and discharge planning. Older patients may
needmodification in the discharge teaching plan because ofcognitive
impairment, physical limitations such asarthritis, and an inherent
discomfort with technology.28
These patients may need a 24-hour companion whereyounger
patients do not. This requirement will putmore strain on the family
or caregivers and plans willneed to be in place to address this
issue.29
ReimbursementThe CMS have recently made significant changes in
thereimbursement for implantable LVADs and for theapproved external
LVADs. These figures are containedin the Medicare Hospital
Inpatient ProspectivePayment System Final Rule for fiscal year 2005
(www.cms.hhs.gov/providers/hipps/frnotices.asp).
Basically, the new rule, effective October 1, 2004,improves
payment for destination therapy and bridge
to transplant. CMS has reclassified implants ofimplantable
pulsatile LVADs from diagnosis relatedgroup (DRG) 525 to DRG 103.
This is significantbecause DRG 525 previously reimbursed
substantiallyless than DRG 103, which is the category for
hearttransplantation. The LVAD implant surgery and sub-sequent
recovery is often more complex and associ-ated with a longer length
of stay, both in the intensivecare unit and the hospital in
general. Now, patientswho are discharged longer than 30 days after
LVADimplant and readmitted for a later heart transplant areable to
be classified as DRG 103 a second time, allow-ing for a second
payment for the transplant surgeryand hospitalization. The base
reimbursement rates forDRG 525 are $56,500 and $97,200 for DRG
103.
Examples of how reimbursement would occurwith different types of
LVADs can be illustrated usingthe Thoratec extracorporeal device
versus animplantable device. A Thoratec extracorporeal LVADwould
fall into category 525 but if the heart trans-plant occurs during
the same hospital admission,reimbursement would be based on the
transplantDRG 103. If the Thoratec patient is discharged formore
than 30 days and readmitted for transplant, thereimbursement rate
for the first admission would bebased on DRG 525 and on DRG 103 for
the secondadmission. A patient who receives an implantedLVAD would
be classified under DRG 103. If theheart transplant occurs during
the same admission,reimbursement for both surgeries is based on
thatone DRG. If the same patient is discharged with theimplanted
LVAD for greater than 30 days and read-mitted for a later heart
transplant, the institution willbe reimbursed based on 2 DRG 103s.
These changeswill likely open the door for wider use of LVAD
ther-apy by more institutions.
ConclusionAlthough an attempt has been made to present
anobjective overview of the devices described in thearticle, the
current methods of recording, analyzing,and publicizing information
regarding adverse eventsand outcomes are often not standardized
sufficientlyto allow for meaningful comparisons of the
devices.Pooling of these data in an international databasewhere
standardized definitions are employed shouldhelp with future, more
accurate comparisons.
We are on the verge of seeing a variety of end-stage heart
failure patients being supported on long-term assist device
therapy. Many pumps havenow or will shortly be proven to be
effective and reli-able for long-term support of these patients
with anacceptable complication rate. Because of changes
inreimbursement rates, the use of these devices willbecome more
widely accepted. We still have a lot to
-
S30 Journal of Cardiovascular Nursing ❘ September/October
2005
learn about appropriate candidate selection andwhen we do, the
therapy will become more cost-effective. This patient population
represents anopportunity for advanced practice nursing to step
inand provide direction for this new population ofindividuals who
will need chronic care and support.
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