Background: Off-pump coronary artery bypass (OPCAB) surgery for posterior and inferior wall vessels requires heart displacement, which leads to hemodynamic instability. Based on results indicating that displacement primarily alters right heart function, this study evaluates the safety and efficacy of right heart support during OPCAB surgery to the posterior and inferior wall vessels.
Methods: In a multi-center, prospective study, 25 patients underwent multi-vessel OPCAB surgery. Right heart support was carried out using the Enabler circulatory support system (Hemodynamics Systems Ltd., Upper Yokneam, Israel). Hemodynamic measurements were recorded at baseline and during heart displacement with and without right heart support.
Results: No mortality was recorded. Mean graft number was 2.25 +/- 0.36. Inability to position the Enabler system occurred in five cases. Once the Enabler was properly positioned, there was no case of conversion to cardiopulmonary bypass (CPB) due to failure of the Enabler to provide adequate support. Cardiac index (CI) declined from 2.4 +/- 0.5 L/min x /m2 to 1.6 +/- 0.6 L/min x /m2 (p <0.05) during heart displacement and increased to 2.3 +/- 0.6 L/min x /m2 (p <0.05) following Enabler activation. Mean arterial blood pressure (MAP) dropped from 82 +/- 18.6 mmHg to 53.1 +/- 16.6 mmHg (p <0.001) during heart displacement and was restored to 69.8 +/- 19.4 mmHg (p <0.001) with Enabler support.
Conclusions: Heart displacement caused a significant hemodynamic deterioration that was stabilized with right heart support. The Enabler system is safe and effective in facilitating multi-vessel OPCAB surgery. However, there are still serious technical problems during cannula insertion that cause an unacceptable failure rate of device utilization.