Hemodynamic changes and right heart support during vertical displacement of the beating heart

Backgrond. Hemodynamic instability during heart displacement in off-pump mu ltivessel coronary artery bypass grafting might be related to right heart d ysfunction. The Enabler (HemoDynamics Systems Ltd, Upper Yoqneam, Israel) i s a cannula pump that expels blood from the right atrium into the pulmonary artery. We studied the hemodynamic changes and the role of the enabler dur ing heart displacement. Methods. Nine anesthetized sheep were assessed for hemodynamic changes duri ng 90-degree heart displacement with or without Enabler support. Hemodynami c parameters included cardiac output, systemic arterial blood pressures, an d left and right heart filling pressures. Results. Heart displacement caused a significant decrease in cardiac output and systemic blood pressure (46% +/- 5%, p = 0.001; and 20% +/- 5%, p = 0. 009, respectively), with a concomitant 137% +/- 24% (p = 0.003) increase in central venous pressure. No significant change in left atrial pressure was observed. Activation of the Enabler caused a significant increase in cardi ac output and systemic blood pressure (67% +/- 150, p = 0.01; and 17% +/- 7 %, p = 0.04, respectively), as well as a decrease in central venous pressur e by 49% +/- 8% (p = 0.0001). Conclusions. Heart displacement causes hemodynamic instability mainly by ri ght heart dysfunction. The Enabler significantly stabilized circulation dur ing vertical displacement of the beating heart. (C) 2000 by The Society of Thoracic Surgeons.