The pulsatile pump (A) fills with blood. When the sensors indicate it is full, the blood is ejected out of the device (B) through a one- way valve to the aorta or pulmonary artery. The pump rate may not equal the heart rate.
What is a ventricular assist device (VAD)?
A ventricular assist device (VAD -- also called ventricular assist system or VAS) is a mechanical pump that is implanted to help the heart’s weakened ventricle (major pumping chamber of the heart) pump blood throughout the body.
The VAD can be used as a bridge-to-transplant, which means it can help a patient survive until a donor heart becomes available for transplant. This option may be appropriate for people whose medical therapy has failed and who are hospitalized with end-stage systolic heart failure. As a bridge-to-transplant, the VAD allows the patient to be discharged to an outpatient setting while waiting for transplant. Without this device, there is a greater risk of death during the wait for a transplant.
The VAD also can be used as destination therapy, which is an alternative to heart transplant. Destination therapy provides long-term support in patients who are not candidates for transplant.
When used as a bridge-to-transplant or as destination therapy, the VAD provides effective hemodynamic support, maintains or improves other organ function, improves exercise performance and enables participation in cardiac rehabilitation.
The continuous flow pump produces a continuous, nonpulsatile flow of blood through the circulatory system using only one moving part—a rotary pumping mechanism.
How does the VAD work?
A VAD does not replace the heart. It assists the patient’s own heart to pump blood throughout the body, decreasing the work of the left ventricle.
Blood flows from the ventricle into the pump (which may be internal or external). A left ventricular assist device (LVAD) receives blood from the left ventricle and delivers it to the aorta. A right ventricular assist device (RVAD) receives blood from either the right atrium or right ventricle and delivers it to the pulmonary artery. Some VADs can perform the functions of either an LVAD or a RVAD, or both (BiVAD).
What are the components of the VAD?
There are several types and sizes of VADs. The size of the device depends on its function. The type of VAD selected will depend on each patient’s individual needs and medical condition. The components of the VAD vary, according to the specific device used. In general, the device consists of a pump unit (which may be implanted in the abdomen or be outside the body), a control system and an energy supply. Below is a diagram of one type of VAD called the HeartMate II and its components.
Outflow tube (A) attached to the aorta (the large artery that carries blood away from the heart)
Inflow tube (B) (or conduit), attached to the bottom (apex) of the left ventricle
Power source (C) The HeartMate requires either electrical power or battery power to work. Pictured here, the device is operating on battery power.
Pump unit (D)
Driveline (E) that passes from the internal device through the skin, and outside your body to the controller. It contains the electrical cables that power the pump.
External controller (F) (outside the body) that attaches to the pump through the power leads and to either a power base unit or batteries. The controller is a computer that monitors the pump’s function. It displays the status of the system and has alarms that sound when necessary.
When the unit is untethered, rechargeable batteries are used when the patient wants to be mobile. The batteries are changed as needed. The power base unit or alternate source is used to recharge the batteries. The controller and batteries can be worn in a belted waist pack or alternate carrying device.
When the unit is tethered, the power supply is provided by a device called a power base unit that is plugged into an electrical outlet.
Untethered Pump Operation
Tethered Pump Operation
Who is eligible to receive a VAD?
A VAD is a treatment option for certain patients with end-stage heart failure. Your doctor will determine if a VAD is an appropriate treatment for you, based on your medical condition, symptoms, age, body size and presence of other medical conditions.
A VAD may not be the appropriate treatment choice for some patients who have blood clotting disorders, irreversible kidney failure, severe liver disease, severe lung disease, or infections that can not be treated with antibiotics.
What are the risks of the VAD implantation procedure?
As with any surgical procedure, there are risks to the VAD implantation procedure. Your doctor will talk with you about the specific risks and potential benefits of this procedure. Some of the possible risks include bleeding, development of blood clots, respiratory failure, kidney failure, stroke, infection and device failure. Special precautions are taken to decrease these risks.
There may be other possible risks. When you meet with your doctor, please ask questions to make sure you understand why the procedure is recommended and the potential risks of the procedure.
How long can I be supported with a VAD?
The amount of time you can receive support from a VAD is variable, depending on the type of system you receive, whether the VAD was implanted for bridge-to-transplant or destination therapy, and your medical condition.
The average support duration for bridge-to-transplant applications varies, since the time needed to wait for transplant varies.
How will I know how to care for my VAD?
To enhance quality of life, all patients with a VAD must carefully follow the guidelines provided by their health care team.
After the implantation procedure, a detailed education program is provided to you and your caregivers to ensure safety and proper use of the device. You’ll learn how to manage the device and trouble-shoot potential emergency situations. You’ll be required to demonstrate your knowledge about the device before you are discharged from the hospital. You’ll also need to demonstrate independence with self-care activities before you are discharged.
You will learn about activity guidelines, medications, diet and when to call the doctor.
You will receive information about how to page the health care team when necessary. A medical team member is always available to answer your questions, 24 hours a day.
The Cleveland Clinic Experience
For more than a decade, surgeons in the Kaufman Center for Heart Failure at Cleveland Clinic have successfully utilized ventricular assist devices (VADs) as a bridge- to-transplant for patients awaiting heart transplantation. The Cleveland Clinic has one of the most experienced VAD programs in the United States. The Cleveland Clinic has access to FDA- approved ventricular assist devices, as well as new investigational devices.
For certain patients with severe heart failure, the Kaufman Center is approved by the Centers for Medicare and Medicaid Services and the FDA to offer destination therapy.
Cleveland Clinic is an approved site for disease- specific care for ventricular assist devices as of December 29, 2008.
If you need more information or would like to make an appointment with a specialist, contact us, chat online with a nurse or call the Miller Family Heart and Vascular Institute Resource & Information Nurse at 216.445.9288 or toll-free at 866.289.6911. We would be happy to help you.
This information is provided by Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition.
Copyright 2009 Cleveland Clinic. All rights reserved. 12/09