Circulatory & Ventricular Assist Devices (VAD)
For some patients, conventional treatments are inadequate to relieve the effects of heart
failure. Under these circumstances, mechanical circulatory support is considered. There are now a
variety of devices capable of pumping blood to restore circulation of vital organs, even
temporarily replacing the function of the native heart. Once the patient is stabilized, procedures
such as bypass surgery, stent insertion, and/or medications can be offered to assist the injured
heart to recover. Alternatively, if damage to the heart is beyond repair, patients can be
considered for heart transplantation or implantation of more permanent heart replacement pumps
that can allow individuals to lead active and productive lives.
Examples of the many options for mechanical circulatory assistance available at the
Center for Circulatory Support at the University of Michigan include:
Abiomed AB5000™ Ventricular Assist Device (Abiomed, Inc., Danvers, MA)
The ABIOMED AB5000™ Circulatory Support System is a short-term mechanical system that can
provide left, right, or biventricular support for patients whose hearts have failed but have the
potential for recovery. The AB5000™ can be used to support the heart, giving it time to rest
– and potentially recover native heart function. The device can also be used as a bridge to
definitive therapy. The AB5000™, recently approved by the US Food and Drug Administration (FDA),
builds upon more than 20 years of research and development for similar technologies, including
the ABIOMED BVS 5000™.
Abiomed BVS 5000™ Ventricular Assist Device (Abiomed, Inc., Danvers, MA)
The ABIOMED BVS 5000™ is used worldwide for temporary left, right, or biventricular (both
ventricles) support in patients with potentially reversible heart failure. It was the first heart
assist device approved by the US Food and Drug Administration for the support of post-cardiotomy
patients (those who have developed heart failure as a result of heart surgery). Since that time,
hundreds of patients have been sustained by the BVS 5000.
Abiomed™ Impella Percutaneous Ventricular Assist Device
The Abiomed™ Impella 2.5 is a minimally invasive, catheter-based cardiac assist device designed to assist the failing heart. The Impella 2.5 is the "world's smallest heart pump", designed to be inserted percutaneously in the catheterization laboratory (cath lab) via the femoral artery into the left ventricle. Up to 2.5 liters of blood per minute are delivered by the pump from the left ventricle into the ascending aorta, providing the heart with active support in critical situations. The Impella 2.5 is FDA 510(k) for short-term circulatory support.
Berlin Heart® Ventricular Assist Device (Berlin, Germany)
The Berlin Heart® is a ventricular assist device which can be configured to support any size
pediatric patient from newborn to full-grown teenager. The Berlin Heart has been used extensively
in Europe as a bridge to transplant, and in some cases, a bridge to recovery. Although it is not
currently FDA approved, special permission can be obtained for implantation in the United States.
At the University of Michigan's C.S. Mott Children's Hospital, many children have undergone
ventricular assist device implantation using a variety of devices, including the Berlin Heart®.
CardiacAssist TandemHeart™ pVAD Ventricular Assist Device
The CardiacAssist TandemHeart™ Percutaneous Ventricular Assist Device (pVAD) differs from other assist devices in that it can be inserted either by cardiovascular surgeons in the operating room or by a cardiologist in the cardiac catheterization laboratory. The TandemHeart™ has been used in postcardiotomy cardiogenic shock patients (those who have developed heart failure as a result of heart surgery or a heart attack) and as a bridge to a more definitive therapy. The TandemHeart™ pVAD provides short-term support from a few hours up to 14 days, giving the heart time to recover and regain native function.
CardioWest™ temporary Total Artificial Heart (TAH-t)
This medical device is the modern version of the Jarvik 7 artificial heart first implanted into
Barney Clark in 1982. The CardioWest™ temporary Total Artificial Heart is the only FDA approved temporary total artificial heart in the world. The TAH-t is used as a bridge to heart transplant for eligible patients suffering from end-stage biventricular failure.
HeartWare® Left Ventricular Assist Devices (LVAD)
The HeartWare® Left Ventricular Assist System (LVAS) is a third-generation continuous flow blood pump for the treatment of advanced heart failure. It features a miniaturized centrifugal pump, which is small enough to be implanted above the diaphragm in all patients. The device is capable of generating up to 10 liters per minute of blood flow. The pump has only one moving part, the impeller, which spins at rates between 2,000 and 3,000 revolutions per minute. The impeller is suspended within the pump housing through a combination of passive magnets and a hydrodynamic thrust bearing. This hydrodynamic suspension is achieved by a gentle incline on the upper surfaces of the impeller blades. When the impeller spins, blood flows across these inclined surfaces, creating a "cushion" between the impeller and the pump housing. The HeartWare VAD, has been approved for sale in the European Union and is currently in clinical trial in the United States.
Click here to view an animation of the HeartWare® Ventricular Assist System. Courtesy of HeartWare, Inc.
Terumo Heart DuraHeart™ LVAD
The DuraHeart™ LVAD is a third-generation continuous flow blood pump designed for long-term patient support. It incorporates a centrifugal flow rotary pump with a magnetically levitated impeller to pump blood from the heart around the body. The DuraHeart™ LVAD is the first device to reach clinical trial that combines centrifugal pump and magnetic-levitation technologies. Weighing 19 ounces (about 540 grams) and measuring about 2.87 inches in diameter and 1.82 inches thick, it is a small device that provides support to a wider range of patient. The unique design of the DuraHeart™ LVAS incorporates, flow rates from two to eight liters per minute with motor speeds between twelve hundred and twenty-four hundred revolutions per minute and flow rates that vary with physiological changes. The DuraHeart™ is an investigational device and is currently in clinical trial in the United States.
Click here to view an animation of the Terumo Heart DuraHeart™. Courtesy of Terumo Heart, Inc.
Thoratec HeartMate II® Left Ventricular Assist Device
The HeartMate II® is a high-speed, axial flow, rotary blood pump. As an axial flow device, the HeartMate II® produces no pulsatile action. Weighing 12 ounces (about 375 grams) and measuring about 1.5 inches (4 cm) in diameter and 2.5 inches (6 cm) long, it is significantly smaller than other currently approved devices. As such, it may be suitable for a wider range of patients, including small adults and children. The University of Michigan Center for Circulatory Support participated in the first clinical testing of the HeartMate II® device in the United
Click here to view an animation of the HeartMate II®. Courtesy of Thoratec.
Thoratec HeartMate® XVE Left Ventricular Assist Device
The Thoratec HeartMate® XVE LVAD (vented electric) was developed and tested by Thermo
Cardiosystems, Inc. This titanium blood pump consists of a blood chamber, motor chamber,
drive-line, and inflow and outflow conduits. The pump weighs 1150 grams. Each conduit contains a
25-mm porcine (pig) valve within a woven Dacron™ fabric graft. A polyurethane diaphragm separates the blood chamber and the motor chamber. Textured surfaces within the blood chamber promote the development of a cellular lining, which helps prevent blood clots and infection. The XVE LVAS has a maximum stroke volume of 83 milliliters. It can be operated at up to 120 beats per minute, resulting in flow rates of up to 10 liters per minute.
Thoratec CentriMag® Blood Pump
The Thoratec CentriMag® blood pump is an extracorporeal circulatory support device for patients with a failing heart. The CentriMag® is a magnetically-levitated pump impeller which provides a contact-free environment to help minimize blood-related complications such as hemolysis. It is capable of delivering high flows up to 9.9 LPM. FDA 510K approved, the CentriMag can be used as a short-term solution to support the circulation while longer-term options are considered. CentriMag is approved for use as an RVAD for periods of support up to 30 days for patients in cardiogenic shock due to acute right ventricular failure. CentriMag is also being evaluated in the United States for use in failure to wean patients as a bridge to recovery, transplant, or a long-term VAD in patients unable to be weaned from cardiopulmonary bypass.
Thoratec IVAD™ Ventricular Assist Device
The Thoratec IVAD™ is now FDA approved for use in bridge-to-transplantation and post-cardiotomy recovery patients who are unable to be weaned from cardiopulmonary bypass. The IVAD™ is the only currently approved, implantable cardiac assist device that can provide left, right or biventricular support. It was recently approved for use in Europe. The IVAD's compact size facilitates implants to assist both ventricles and enables it to accommodate a wide range of patients, including those who were previously unable to receive an implantable, pulsatile device.