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The Thoratec HeartMate® XVE Left Ventricular Assist System is an FDA approved device for both bridge-to-transplantation therapy and destination therapy. The original version of this device, the Vented Electric (VE), included an internal lining designed to reduce the possibility of blood clotting. Based on results from the REMATCH trial (Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure), an enhanced version of the device was developed—the Extended Lead Vented Electric (XVE). Thoratec HeartMate XVE offers surgeons an easier means of implantation, and offers patients added comforts. Specific improvements in the Thoratec HeartMate XVE include a longer lead with a smaller diameter and greater flexibility, as well as new controller software that reduces the amount of wear on the moving parts of the device (leading to a longer device life). The device is placed in the chest and is attached to the left ventricle and the aorta. A cable extends through the abdomen and connects to an external controller unit. The pump can be powered by a unit that plugs into the wall or by a wearable battery pack that allows greater mobility for the patient. The Thoratec® VAD system is the only system that provides left, right, or bi-ventricular assistance to patients with end stage heart failure. It has been FDA-approved as both a bridge-to-transplant therapy and for postcardiotomy recovery from open-heart surgery. The VADs are prosthetic ventricles which are composed of blood sacs inside of a hard plastic casing. A pressure/vacuum system allows air to enter the casing around the blood sac. This expansion and contraction of the air sacs allows the VAD to fill and eject blood, and provides the body with blood flow similar to that of the native heart. Thoractec VADs exist outside the body. The Novacor® Left Ventricular Assist System (LVAS) is an electromechanically driven pump device used primarily for bridge-to-transplant cases. It is currently in clinical trials for use as a destination therapy. The LVAS takes over most of the workload of the left ventricle. Blood enters the pump through an inflow conduit connected to the left ventricle and is ejected through an outflow conduit into the body's arterial system. The system is monitored by an electronic controller and powered by primary and reserve battery packs. The controller is connected to the implanted pump by a small tube containing control and power wires through the recipient's skin. The device is known to be reliable for long-term use. The ABIOMED BVS®5000 Biventricular Support System and AB5000™ Circulatory Support System provide temporary support for one or both sides of the heart to assist patients with potentially reversible heart failure. The most widely used cardiac assist system, the BVS-5000 is an air-driven blood pump which is placed outside the body. The dual-chamber design is similar to the natural heart. Approved by the FDA in 2003, the AB5000 is designed to provide improved patient mobility, comfort, and ease of use. Devices in Clinical Trials
The Thoratec HeartMate® II LVAS (Left Ventricular Assist System) is an implantable second-generation device intended for long-term cardiac support for patients with end stage heart failure who are awaiting transplantation. The HeartMate II employs a rotary blood pump that is expected to have a significantly greater pump-life than the mechanism used in the HeartMate VE and XVE. The HeartMate II is about 1/8th the size of the HeartMate XVE and is therefore suitable for a wider range of patients, including petite adults and children. The device provides blood flow through the circulatory system on a continual basis, and its small size makes it easier to implant than pulsatile devices. The HeartMate II is designed to operate more simply and quietly than other approved devices. Another unique feature of the device is its automatic speed control mode that is designed to regulate pumping activity based on different levels of patient or cardiac activity. Read about the phase II trial. The MicroMed DeBakey VAD® is a second-generation miniature heart pump designed to provide increased blood flow (up to 10L/min) from the left ventricle of the heart throughout the body for patients with end stage heart failure. It can be used for both a bridgeto-transplantation and destination therapy. The device is only about three inches long and one inch wide. The smaller size results in reduced surgical time and offers treatment hope for patients with smaller body sizes, such as petite women and children. The DeBakey employs only one moving part–an impeller to pump blood throughout the body–making it quieter than many other devices. It also potentially offers patients greater mobility through the VADPAK, a portable controller and battery pack that powers the pump. The impella® recover is under investigation for the provision of temporary support to either or both sides of the heart in patients with severe heart failure. It offers the smallest and only minimally invasive mechanical cardiovascular support system, which can be inserted and removed through an incision in the groin. With a diameter of only 6.4 mm, the electric motor can pump 5 to 6 liters per minute, while potentially reducing the amount of damage to the blood, the need for hemodilution medications such as heparin, and the and the risk of infection. Specific systems include:
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| ©1999-2007. Columbia University Medical Center, Department of Surgery, New York, NY. |
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