What is a Left Ventricular Assist Device (LVAD)?

sarahvandevrede, BSN

If you are a nurse at a rural hospital, you may have had a patient arrive at your hospital with an LVAD, and you may have felt uncomfortable with this unfamiliar device. If so, you probably wanted to learn more about LVADs and how to properly care for your patient. Read this article to learn more about LVADs and what steps you can take if you happen to have a patient show up at your hospital with an LVAD.

Disclaimer. Nurses who work at LVAD centers are trained on how to properly care for patients with LVADs. This article is not considered a training manual and does not encourage untrained nurses to manage LVAD devices; however, it provides an overview of what an LVAD is for your knowledge base and what to expect if you happen to see one in your hospital.

What is an LVAD?

LVAD stands for Left Ventricular Assist Device. An LVAD is a treatment device for advanced heart failure. The goal of the LVAD is to assist the heart in circulating blood to the body in a heart that is otherwise too weak to adequately pump blood. The device is implanted in the apex of the left ventricle and connects to the aorta via a cannula. Using power, the device moves oxygenated blood from the left ventricle to the body. A driveline cable connects the internal portion of the device to an external power source by exiting the body through the abdomen. The exit point is commonly called the driveline site. Once outside the body, the driveline connects to the controller (the brain of the device) and two power sources.

An LVAD device essential replaces the pumping action of the heart. Current devices are commonly referred to as continuous-flow devices. This means that blood is continually circulated through the device and to the body, thus masking the pulsatile effect of the heart, often eliminating pulse detection.

Indications

Listed below are three common treatment tracks for patients with LVADs.

1- Bridge-to-Transplant

This treatment option is used for patients who qualify for a heart transplant and are listed on the heart transplant list. Patients in the bridge-to-transplant track will get an LVAD temporarily until a donor's heart is available.

2- Destination Therapy

Patients who do not qualify for heart transplants fall into the destination therapy category. For these patients, an LVAD is the final treatment option for their advanced heart failure. In this tract, most patients keep the device for life.

3- Bridge-to-Recovery

Patients who need temporary left ventricular support fall into this category. The goal is to remove the device after the heart shows signs of recovery.

Components of an LVAD

Implanted pump. This is the internal portion of the device. The pump is implanted in the apex of the left ventricle and connects to the aorta via a cannula.
Controller. The controller is located outside the body and monitors the pump. It is considered the brain of the device. If something is wrong, it will notify you with alarms.
Driveline. The driveline has both an internal and external portion. It connects the internal pump to the external controller by exiting the body through the abdomen. The exit point is called the driveline site.
Power source. The external power source connects to the controller and powers the pump. This component is extremely important because, without power, the device does not run. Some devices have a temporary backup power source built inside the pump, but patients are taught never to rely on this.

What does Life Look Like with an LVAD?

Patients can live fairly normal lives with LVAD devices. They are encouraged to be active. Some patients get back to dancing, gardening, golfing, and even playing tennis. Patients will take anticoagulants for as long as they have the device. They are not allowed to swim because they can't submerge the device in water and are discouraged from doing contact sports because of bleeding risk.

No pulse? No blood pressure? No Problem!

Because LVADs are continuous flow devices, it is common for patients not to have palpable pulses or easily detected blood pressures. Instead, clinicians measure and monitor mean arterial pressure (commonly referred to as MAP) in patients with LVAD devices.

Use a Doppler to Check MAP in an LVAD patient without a pulse

Place a blood pressure cuff on the patient's arm
Using a doppler placed over the brachial artery, listen for an audible swooshing sound
Slowly inflate the blood pressure cuff until the audible sound goes away
Deflate the blood pressure cuff until you hear the return of the audible sound
Record this number as the MAP
The typical MAP goal is 80 mmHg

What are the Risks of LVADs?

Stroke and Pump Thrombosis. The formation of blood clots in the device is a major risk. For this reason, patients will be on warfarin for as long as they have the device. There is a risk for both ischemic and hemorrhagic stroke in patients with LVADs.
Bleeding. Because Patients with LVADs will be on warfarin, the risk for bleeding is high.
Infection. Infection may occur internally in the pump or externally at the driveline site. LVAD coordinators extensively educate patients on at-home driveline site care to prevent infection. The driveline site should be kept clean, dry, and covered. Patients change their dressing sterilely once a day at home.
RHF. There is a risk of right heart failure developing following the placement of an LVAD. RVADs (right ventricular assist devices) do exist; however, they are less commonly seen in the community.

Common Types of LVADs

Let's discuss the most common types of LVADs seen in the community. Medtronic's Heartware (also called HVAD) and Abbott's Heartmate2 and Heartmate3.

Heartware HVAD

The HVAD controller should always have two sources of power; either two batteries, or one battery and one AC/DC power cable. Charge batteries in the battery charger.

Numbers. The HVAD controller has 3 numbers listed on its screen.

RPM shows the speed of the device measured in pump rotations per minute.
L/min monitors blood flow in liters per min.
Watts measures the power level of the pump.

Changes in numbers can indicate complications such as pump thrombosis or worsening heart failure.

Changing power sources. Patients are educated on how to change power sources and batteries. Find out how to change power sources at the end of this article.

Alarms and what they mean. Read about the attached alarm guide from the manufacturer.

Product Update. Medtronic stopped the distribution of new HVADs in June of 2021 due to complications with the pump. Medtronic is not currently recommending the replacement of HVADs, so you will still continue to see patients with HVAD devices in the community.

Abbott's Heartmate2 and Heartmate3

Heartmate3 is Abbott's updated model. Both versions have similar controllers. The heartmate LVAD has a power unit that connects to an AC outlet in order to provide power. Patients will connect to the power unit while they are sleeping or resting indoors. The heartmate also comes with portable batteries. Charge batteries in the battery charger.

Numbers. Both Heartmate2 and Heartmate3 controllers will show 4 numbers on their screen, viewed one at a time by pushing the square display button on the controller.

Pump speed is measured in RPMs (rotations per minute).
Flow Indicates blood flow in Liters per min.
Power is indicated in Watts.
PI stands for pulse index. The range is 1-10 per manufacturer.

Changing power sources. Patients are educated on how to change Heartmate's power sources and batteries. Find out more details at the end of this article.

Alarms and what they mean. Read for further information on Heartmate3 alarms.

Who Should I Contact for Questions or Concerns?

Contact the manufacturer's local device representative.
LVAD patients should know who their local device rep is and how to contact them. Patients should have the rep's contact information readily displayed in their device kits and/or listed on their phones.

Dos and Don'ts with LVADS

Do

Encourage the patient to be the owner of their device if possible while they are hospitalized. Enlist the help of a trained family member if the patient is unable to care for themself.
Always keep the device connected to two sources of power.
Keep the emergency contact number for the manufacturer handy in case of an emergency.
Monitor INR because the patient will be on warfarin. The typical INR goal range is 2-3.
Have the patient change their driveline site daily. This is done using sterile technique. They typically use gauze, spit gauze, betadine, and tape.
Monitor the driveline site. Look for signs of infection.
Always keep at least two backup batteries and the backup controller with the patient at all times.

Don't

Submerge device in water
Change power sources for the patient without training
Disconnect both power sources at the same time!
Manage the pump without official training

Commonly Asked Questions

Q. Can my patient shower?

A. Yes. A special shower bag is used to cover the device to prevent it from getting wet. Dressing changes are performed after a shower.

Q. How do I know if the pump is running?

A. You will hear the humming sound of the pump when auscultating the patient's upper left chest with a stethoscope.

Q. My EKG reading shows artifact. Is this normal?

A. EKG readings are difficult to pick up in patients with LVADs as the device may create electromagnetic interference. Oftentimes it requires adjusting lead placement.

Q. If my patient codes, what do I do?

A. Follow the manufacturer's guidelines. There are risks associated with chest compressions. Both Heartware and Abbott advocate using clinical judgment.

Where Can I Find More Info?

Read more about Medtronic's Heartware HVAD.
Learn more about Abbott's Heartmate2.
Find more info on Abbott's Heartmate3.

How to Change Power Sources for Heartware HVAD

Line up the solid white arrow on the power connector with the red dot on the controller and gently push the cable into the controller until you hear a click. Confirm connection by gently tugging back on the power cable.
To disconnect, grasp the power cable at the connection site. First, turn counterclockwise, then pull the cable out of the controller.
Never Disconnect both power sources at the same time! This will make the pump stop.
For safety, always have 2 power sources connected!

How to Change Power Sources for Abbott's Heartmate2 and Heartmate3

Switching from power unit to battery. Place two batteries in two clips by lining the red arrow on the batteries with the red arrow on the clips until a click is heard. Disconnect the white power cable from the white power unit system. Align the half circles and pins of the white power cable with the first battery and push, tighten until secure. Repeat with the black power cable and the second battery.
Changing from batteries to power unit. Reverse the process by first disconnecting the white power cord from the first battery then connecting it to the white cable on the power unit. Then, disconnect the black cable from the second battery and connect it to the black cable on the power unit.
Changing batteries while on battery power. Press the power release button on the clip and remove the battery. With a new battery, line up the red arrow on the battery with the red arrow on the clip. Repeat with the second battery.
To avoid damage, do not twist the connection when aligning pins
Always connect white to white and black to black

References/Resources

Left Ventricular Assist Devices

Outcomes based on blood pressure in patients on continuous flow left ventricular assist device support: An Interagency Registry for Mechanically Assisted Circulatory Support analysis

Hypertension, Arterial Compliance and LVAD Pump Function

Understanding Left Ventricular Assist Devices

Ventricular assist device (VAD)

Left Ventricular Assist Devices (Mechanical Circulatory Support MCS)

Treating patients with Left Ventricular Assist Device (LVAD)

HeartMate 3™ Left Ventricular Assist Device: PUMP PARAMETER OVERVIEW

HeartMate 3 LVAD

HeartMate II™ Left Ventricular Assist Device

Medtronic HVAD Learning Center