Counterpulsation in atrio-aortic bypass: theoretical and experimental aspects.

Mechanical support of the heart is becoming an established method for emergency situations or bridge to transplant applications. Nevertheless the discussion concerning the importance of co- or counterpulsation isn't yet finished. Using a theoretical model of the cardiovascular system, the influence of a LVAD triggered to co- and counterpulsation will be discussed. The theoretically obtained results are compared to a series of six experiments in calves, where the influence of LVAD-pumping in co- and counterpulsation pumping mode was investigated. Additional benefits were seen compared to the copulsation pump method: there was more reduction of the cardiac stroke work, afterload and an increase of the diastolic pressure, which is important for the coronary blood flow. In order to verify the benefits of the additional reduction of pressure work a small series of animal experiments was performed.