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romac |
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University of Virginia Rotating Machinery and Controls Laboratory P.O. Box 400746 122 Engineer’s Way Charlottesville, VA 22904 (434)924-3292 (434)982-2246(fax) |
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Rotating Machinery and Controls Laboratory |
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HEARTPUMP PROJECT
When a patient has long term congestive heart failure, the native heart pumps at a flow rate much below the normal rate of approximately 6 liters per minute. Over a long period of time with this disease, the human body is starved for blood flow and eventually we die. An estimate of the need for long term implantable blood pumps ranges from 17,000 to 240,000 patients annually in the U.S. that could benefit from such a system. At this time, the most promising approach is to use a ventricular assist device in the configuration shown in Fig. 1. Heart failure is diagnosed in nearly 500,000 new patients each year and is the primary diagnosis for over 900,000 hospitalizations a year in the U.S with an estimated total cost exceeding $10 billion/year. Initially the VADs were limited to bridge to cardiac transplantation (BTT). Recently, however, the FDA has approved the HEARTMATE I and the MicroMed-DeBakey VAD for long-term, i.e. destination, therapy. The left ventricular assist device (LVAD) is located just below the diseased heart and pumps in parallel with the native heart as illustrated in Fig. 1. A hole is placed in the left ventricle and an inlet cannula is brought to the axial flow LVAD which rotated continuously at a speed of approximately 8.000 rpm. It pumps additional blood (beyond that of the diseased native heart) through the discharge cannula up to the aorta and back into the bloodstream. It is powered by a battery and the speed controller contained in an external pack and connected to the LVAD pump by a wire placed through the skin.
LEV-VAD2 Developed by Utah Artificial Heart Institute/University of Virginia/Flowserve/Kipp Engineering A new magnetically suspended ventricular assist device is currently under development as funded by the National Institute of Health. The University of Virginia is responsible for the flow design and testing (Houston Wood of ROMAC), magnetic suspension and electronics (Paul Allaire and Zongli Lin of ROMAC). Kipp Engineering is responsible for design drawings of the pump and Flowserve (ROMAC Industrial Member Company) is responsible for pump manufacture. Utah Artificial Heart Institute is responsible for animal testing, in cooperation with the University of Virginia Heart Surgery Team, and overall administration of the project. These systems are acknowledged by the blood pump development community as the ultimate in mechanical blood pumps. There are several 3rd generation pumps being developed to provide continuous flow with an impeller suspended with magnetic bearings. The previously developed CFVAD by the UAHI, UVA and MedQuest Products was the first to demonstrate feasibility of a totally suspended (no physical contact) impeller, and the only system incorporating a centrifugal pump to facilitate a simplified control mechanism. The first prototype of the pump is currently undergoing design finalization and manufacturing by UVA, Flowserve, and Kipp Engineering. It is expected that the first pumps will be produced in June, 2006, be flow tested and magnetically levitated at UVA in July and tested in animals in August 2006 by UAHI and UVA. For additional information on this project, see our ROMAC Newsletter.
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