News Release

Experimental, implantable device may give patients greater freedom while supporting heart

Peer-Reviewed Publication

Cedars-Sinai Medical Center

LOS ANGELES (Mar. 14, 2003) – Cedars-Sinai Medical Center's cardiothoracic surgery department is one of 10 centers nationwide participating in a study of an experimental, implantable ventricular assist device that may provide improved mobility and quality of life for patients whose hearts need temporary support.

A ventricular assist device (VAD) is used as a bridge to recovery or a bridge to transplantation, helping to pump blood for days, weeks, months or even years until the heart is able to function on its own or until a donor heart becomes available for transplantation. Just a few years ago, assist devices and their control units and power sources were large, unwieldy bedside machines that required patients to stay in the hospital. But as the devices become smaller and more sophisticated, patients grow increasingly mobile.

The new Intracorporeal Ventricular Assist Device (IVAD), developed by Thoratec Corporation, consists of a small pump that is positioned inside the chest wall and upper abdomen and connected by a thin, flexible line to a control unit and battery pack that are about the size of a briefcase. The control unit monitors the pump and adjusts its pumping rate as needed. Although the device has been tested in animal studies, this is the first time that it will be tested in humans.

Weighing less than a pound, the pump can be adapted to take over the work of the left side of the heart (left ventricle) or the right side of the heart (right ventricle). If needed, two IVADs can be implanted to support both ventricles. Previously, the only assist devices that provided biventricular support were placed outside the body at the front of the abdominal wall (paracorporeal) with tubes crossing through the diaphragm to the chest to connect to the heart and vessels.

The IVAD's small size – about half that of existing implantable left-ventricular systems – makes the implantable pump an option for many smaller patients whose chest cavities were not able to accommodate the larger size, according to Kathy E. Magliato, M.D., Cardiothoracic Surgeon and Director of the Cardiac Mechanical Assist Device Program in Cedars-Sinai's Division of Cardiothoracic Surgery. Dr. Magliato is the principal investigator in the IVAD study at Cedars-Sinai.

Thoratec based the intracorporeal device on its well-established paracorporeal VAD system. Blood flow path and many other details are virtually identical, although the new pump housing consists of contoured, polished titanium alloy, designed to reduce the risk of infection, organ compression and other potential complications.

To reduce the pump's size as much as possible, the complicated electromechanical components of the control unit remain outside the body. This also allows the control unit to be serviced or replaced without subjecting patients to additional surgery.

The new IVAD, which is being tested for the first time in humans, may enable more patients of various body sizes to receive an implanted device, whether they need one or both ventricles supported. It also may allow more patients to have greater mobility and shorter hospitalizations. Patients may be able to return home with their assist device in place to await heart transplantation or recovery of their heart's function. They would be able to resume their normal daily activities and have a better quality of life.

Despite these advantages, the IVAD is not intended to completely replace the paracorporeal system, which will continue to be preferred for shorter-term ventricular assistance and in a number of other instances.

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Cedars-Sinai Medical Center is one of the largest nonprofit academic medical centers in the Western United States. For the fifth straight two-year period, it has been named Southern California's gold standard in health care in an independent survey. Cedars-Sinai is internationally renowned for its diagnostic and treatment capabilities and its broad spectrum of programs and services, as well as breakthrough in biomedical research and superlative medical education. Named one of the 100 "Most Wired" hospitals in health care in 2001, the Medical Center ranks among the top 10 non-university hospitals in the nation for its research activities.


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