TheIn and Outs
Of TheVentricular Assist Device
By: Nicholas Todd
Objectives
• Define Ventricle Assist Device• Identify hemodynamic differences in patients with
a VAD• List VAD related complication• Demonstrate how to assess a patient with a VAD• Describe how to treat VAD complications • Identify VAD resources that can be utilized when
caring for these patients
What is a VAD?
• A left ventricular assist device (LVAD) is a pump that is used for patients who have reached end-stage heart failure or awaiting a heart transplant. The LVAD’s are surgically implanted and are attached to the left ventricle and aorta. The LVAD is a battery-operated, mechanical pump, which then helps the left ventricle pump blood to the rest of the body.
Ventricular Assist Device (VAD)
• A mechanical pump that is surgically attached to one of the heart’s ventricles to augment or replace native ventricular function
• Can be used for the left (LVAD), right (RVAD), or both ventricles (BiVAD)
• Are powered by external power sources that connect to the implanted pump via a percutaneous lead (driveline) that exits the body on the right abdomen
• Pump output flow will be non-pulsatile
Indications for VAD Bridge to transplant
(BTT)• Most common• Allow rehab from
severe CHF while awaiting a donor heart
“Destination” therapy (DT)• Permanent device,
instead of transplant • Currently only in
transplant-ineligible patients
Bridge to recovery (BTR)• Unload heart, allow
“reverse remodeling”
• Can be short term or long term
Bridge to candidacy (BTC)/ Bridge to decision (BTD)• When eligibility
unclear at implant• Not true “indication”
but for many pts
VAD Setup Continuous-flow devices
• Impeller (spinning turbine-like rotor blade) propels blood continuously forward into systemic circulation.
• Axial flow: blood leaves impeller blades in the same direction as it enters (think fan or boat motor propeller).
Most implanted devices are LVADs only LVAD’s are quite and cannot be heard outside of the patient’s
body. Assess VAD status by auscultation over the apex of the LV. The VAD should have a continuous, smooth humming sound.
The Patient may have a weak, irregular, or non-palpable pulse
The Patient may have a narrow pulse pressure and may not be measurable with automated blood pressure monitors. This is due to the continuous forward outflow from the VAD. Recommended use of a Doppler and a manual B/P cuff to obtain B/P.
The Mean Arterial Pressure is the key in monitoring hemodynamics. Ideal range is 65-90 mmHg.
VAD Key Parameters Flow:• Measured in liters per minute• Correlates with pump speed (speed=flow,
↓speed=↓flow)• Dependent on Preload and Afterload
Speed:• How fast the impeller of the internal pump
spins• Measured in revolutions per minute (rpm)• Flow speed is set and determined by VAD
clinical team and usually cannot be manipulated outside of the hospital
VAD Key Parameters Power:• The amount of power the VAD consumes to
continually run at a set speed• Sudden or gradual sustained increases in the
power can indicate thrombus inside the VAD
Pulsatility Index (PI):• A measure of the pressure differential inside
the internal VAD pump during the native heart’s cardiac cycle
• Varies by patient• Indicates volume status, right ventricle
function, and native heart contractility
VAD Key Parameters
The device parameters are displayed numerically on the VAD console or controller
Will vary with each individual patient a VAD device
VAD ParametersParameters for VAD devices vary with
each device model
Patients and their care givers know the expectable parameter ranges and goals for their specific device
Contact the VAD Coordinator at the implanting medical center, they will be your best resource when treating a VAD patient.
Basic VAD Management
VADs are: Preload-dependent EKG-independent Afterload-sensitive Anticoagulated Prone to:• infection• bleeding• thrombosis/stroke• mechanical malfunction
MOST COMMON VADEQUIPMENT
HeartMate II LVAS Internally implanted, axial-flow (non-
pulsatile) device left heart support only speed: 8000-15000 rpm• flow: ~3-8 lpm
Medium- to long-term therapy (months to years)
bridge to transplant (FDA-approved) destination therapy (investigational)
VAD ISSUES
Problems And Complications
Major VAD Complications Bleeding Thrombosis Infection• sepsis is leading cause of death in long-
term VAD support RV dysfunction/failure Suckdown (low preload causes a
nonpulsatle VAD to collapse the ventricle)
Device failure/malfunction (highly variable by device type)
Hemolysis (the VAD destroys blood cells)
Problems And Complications
Other Common Issues Arrhythmias
• A patient can be in a lethal arrhythmia and be asymptomatic. Treat the patient not the monitor.
• Do not cardiovert/ defib. unless the patient is unstable with the arrhythmia.
• Do not initiate chest compressions unless instructed by a physician or VAD coordinator. Chest compressions can disrupt the implanted equipment causing bleeding and death
• Electrical shock from cardiovert/ defib. will not damage any of the VAD equipment
Problems And Complications
Other Common Issues Hypertension
• High afterload can limit VAD flow/ output
• Do not administer antihypertensive medications or nitrates unless instructed by a physician or VAD Coordinator
Hypotension/ loss of Preload• All VADs are preload dependent. A
loss or reduction in preload will compromise VAD function and limit flow/ output
Problems And Complications
Other Common Issues Depression/ Adjustment Disorders
• Living with a VAD is difficult to management for a lot of patients.
• A large percentage of patients experience symptoms of depression
Portability/ Ergonomics• The external VAD equipment is
heavy and cumbersome limiting a patient’s mobility and greatly impacting their quality of life.
Problems And Complications
Bleeding & Thrombosis Careful control of anticoagulation
is imperative• Patients are often on both
anticoagulants and platelet inhibitors
• Device thrombosis Typically revealed by increased
power and signs and symptoms of hemolysis
Problems And Complications
Bleeding & Thrombosis Treatment• Assess for signs and symptoms
of bleeding• Neuro Assessment to rule out
CVA• Initiate IV therapy and
administer fluid slowly to maintain preload
• Device Thrombus is treated with low dose lytics and/ or increasing anticoagulation therapy
Problems And Complications
Infection• The leading cause of mortality in
VAD patients• Higher incidence in pulsatile VADs• The driveline provides direct
access into the body and into the blood stream
• Often recurrent and difficult to treat
Problems And Complications
Suckdown LV collapse due to
hypovolemia/hypotension or VAD overdrive
Indicators: hypotension, PVCs/VT, low VAD flows.
Problems And Complications
Treating Suckdown• Initiate a peripheral IV and
slowly give volume to increase preload
• Assess for signs and symptoms of bleeding and sepsis
Problems And Complications
Device Failure This is a true emergency requiring
immediate transport to the implanting VAD center
Patients & caregivers are trained to identify signs and symptoms of device failure
May require the VAD to be replaced
Problems And Complications
Hemolysis Blood cells are destroyed as they
travel through the VAD
Problems And Complications
Treating Hemolysis• Initiate a peripheral IV and
slowly give volume• If thrombus is suspected to be
causing hemolysis, administer lytics and anticoagulants as able/ ordered
Alarms All VAD devices typically have two
distingue alarms to indicate a problem and it’s severity • Advisory Alarms• Critical/ Hazardous Alarms
Alarms Advisory Alarms are intermittent beeping
sounds that have a corresponding YELLOW light that illuminates on the system controller• Not critical but the device requires
attention• Likely due to low battery, cable
disconnected, or device not functioning properly.
Alarms Hazardous or Critical alarms are a loud,
continuous, shrill sound that have a corresponding RED light that illuminates on the system controller• Indicating the device needs
immediate attention• Often because the pump has
stopped or a problem is detected with the system controller
• Most likely intervention required is to change out the system controller
Field Management
All VADs are dependent on adequate preload in order to maintain proper functioning
Volume resuscitation in an unstable VAD patient is the first line of therapy before vasopressors but be cautious with fluid as to not over load the right ventricle in L VADs only.
Field ManagementNitrates can be detrimental to a VAD
patient because of the reduction in preload
• Results in decreased pump efficiency
• Consult with medical control before administering nitrates per protocol
Field Management
Initiate IV therapy with all VAD patients if possible
• Use aseptic technique due to the patient’s increased risks of infection
Field ManagementVAD patients are susceptible to other
injuries unrelated to the VAD
Contact the VAD Coordinator, they are your most valuable resource when encountering these patients
Consult with medical control about transport
Patient Transport This is emergency, resource and protocol driven
decision makingVAD patients require unique care that not all
medical centers are equipped to handle. Transport to the implanting center when able or the closest VAD center
Make sure when transporting to bring all VAD related equipment
Secure VAD batteries and the controller to prevent dropping or damage. If batteries need to be changed during transport, change one at a time system will alarm during battery change but this is normal and will stop.
Make sure to keep all cables tangle and kink free
Pre-Planning For Transport
Medical Control
• Inquire ahead of time the level of knowledge/ comfort with your medical directors regarding the management of VAD patient
Know Transport Options
• Air vs. Ground
• Know your tertiary facilities and their ability to management VAD patients
Things To Remember
EMS can walk into just about any situationDepending on the individuals- the family may
not be able to handle the emergencyListen to the family members that can handle
the emergency and “assist” them with whatever they need
The only resources/ tools you can truly rely on are the ones you bring to the call
Follow-up and educate yourself to new technologies that keep entering into the industry
Things To Remember
Ask for the contact number for the managing center’s VAD Coordinator as soon as you arrive, this should be on the person or close by. This is the coordinator they work very closely with and will be your best resource
Family, friends, co-workers- listen to them for direction, they should be educated/ trained to assist with most VAD related complications
911 activation may not be for a VAD related emergency
Things To Remember
Emergency bag containing back-up VAD supplies needs to stay with the patient at all times. Should contain extra batteries and the spare system controller
Ask the family for any trouble shooting guidelines that maybe available. This often includes various alarms and interventions
Remember that the family/ friends are not emergency responders or maybe too upset to assist you
If a VAD patient calls 911 it will not be for something simple like a battery change. VAD related emergencies are serious life threatening events
Additional resources materials and information please visit:
www.thoratec.comwww.jarvikheart.comwww.umm.edu/heart/index.htm
THANK YOU FOR YOUR TIME !!!!