The mechanical characteristics and the effects of the circulatory support of left ventricular copulsation in ischemic heart canine preparation--an experimental study
Furukawa, H.
Nihon Kyobu Geka Gakkai 36(9): 2079-2089
1988
ISSN/ISBN: 0369-4739 PMID: 3204298 Document Number: 311729
The mechanical characteristics of left ventricular copulsation (LVCOP) as a new and simple means of circulatory support was evaluated in a mock circulatory system, and the hemodynamic effects were compared with those of intraaortic ballon pumping (IABP) in a canine ischemic heart preparation. In mock circulatory examinations, LVCOP produced 2.7 L/min of maximum line flow, but the flow reduced in an inverse proportion to the driving rate above 100 beats/min. Approximately 2.0 L/min of flow was attained with a cannula larger than 28F in diameter and shorter than 15 cm in length at the driving rate lower than 100 beats/min. A canine ischemic heart was produced by multiple transmural ligations over a left ventricular anterior wall and continuous microdrip infusions of propranolol (0.2 .mu.g/kg/min). In vivo experiment, LVCOP was easily equipped with a commercially available pulsatile bypass pump which was attached to an apical left ventricular vent cannula. Compared to the pre-copulsation level, LVCOP produced a 29.2% increase in mean aortic flow and a 20.3% increase in mean aortic pressure. Improvement in these variables was statistically significant (p < 0.01) and the effect was considered to be about equal to that of IAMP. More than all, the addition of IABP to LVCOP produced further hemodynamic enhancement; mean aortic flow rose by 39.8% and mean aortic pressure by 31.3%. Since mean left ventricular pressure and myocardial oxygen consumption were not significantly increased during LVCOP, the left ventricular load was seemed to be less augmented. An apical left ventricular cannula was safely introduced without causing visible endocardial injuries, and no antiarrhythmic drugs were necessary. Thus, the author concludes that LVCOP may prove a promising circulatory assist secondary to more complex modalities in the management of refractory left ventricular power failure. However, prior to the clinical application, further studies will be needed to solve the problems of anticoagulation, hemolysis and others in long term use.