(Circulation. 1999;100:II-236.)
© 1999 American Heart Association, Inc.
Thoracic Transplantation and Ventricular Assist Devices |
From the Department of Surgery, Division of Cardiothoracic Surgery (J.H.A.), and Department of Medicine, Division of Circulatory Physiology (G.-H.Y., D.B., J.W.), College of Physicians and Surgeons, Columbia University, New York, NY; and Cardio Technologies Inc (H.R.L.), Pine Brook, NJ.
Correspondence to Jie Wang, MD, PhD, Department of Medicine, Division of Circulatory Physiology, College of Physicians and Surgeons, Columbia University, MHB 5-435, 177 Fort Washington Ave, New York, NY 10032. E-mail jw147{at}columbia.edu
BackgroundBiventricular direct cardiac compression (DCC) has the potential to support the failing heart without the complications associated with a blood/device interface encountered with the use of current ventricular assist devices. A clinically designed DCC device that provides compression pressure around the base of the heart in synchrony with native ventricular contractions was evaluated with the use of an ex vivo and in vivo canine model of heart failure.
Methods and ResultsThe device was tested over a series of
ventricular preloads with the use of an ex vivo canine
heart preparation and computerized afterload system that mimicked the
conditions of heart failure. The end-systolic pressure-volume
relation of the left and right ventricles was shifted upward in
parallel by DCC, with the magnitude of the shift averaging 40% of the
device compression pressure. The device was tested in vivo with the use
of a canine model of acute ischemic heart failure in which
graded reductions in ventricular function were created
through serial coronary artery embolizations. Under the most
severe condition of heart failure, DCC improved cardiac output (CO) by
104% (0.80±0.33 to 1.63±0.40 L/min) and mean arterial
pressure by 95% (45.6±11 to 89.0±18.2 mm Hg). The CO was
typically restored to
60% of the normal baseline value, despite
attempts to further increase CO by increasing the amount or duration of
compression pressure.
ConclusionsNonuniform DCC significantly improves the left and right ventricular pressure-generating capability and, in the setting of acute heart failure, can increase CO and mean arterial pressure. Such DCC devices can potentially avoid the complications associated with currently available ventricular support devices that involve a blood/device interface.
Key Words: heart failure hemodynamics ischemia physiology cardiac assist devices
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