On-pump Beating Coronary Artery Bypass Grafting by Ventricular Assist

Off-pump coronary artery bypass grafting (CABG) tends to have a lower incidence of postoperative complications and remarkable advantages in terms of hospital stay. However, some drawbacks include higher rates of incomplete revascularization and the hemodynamic deterioration during manipulation of the heart, more occurring in the cases of posterolateral anatomical constraints and cardiac dysfunction. It leads to urgent conversion to extracorporeal circulation (ECC) and increases the mortality. Although conventional ECC with cardioplegia arrest provides bloodless immovable field, intense systemic inflammatory response may contribute to hemodynamic unstability especially in patients already with severe cardiac dysfunction. On-pump beating CABG, as a more comprehensive approach, not only facilitates stable hemodynamics and complete revascularization, but also supports myocardial lymphatic flow balance and decreases interstitial myocardial edema in the beating state. Especially in the high-risk patients,some findings suggested that off-pump CABG should be converted to on-pump beating CABG without hesitation, avoiding hemodynamic collapse and even catastrophic outcomes. Some investigators intentionally planned on-pump beating CABG aiming to some patients with severe left ventricle dysfunction. Furthermore, on-pump beating CABG with ECC assistance in a high-risk subgroup is also an acceptable trade-off between conventional cardioplegia and off-pump operations. The above-mentioned ECC results about on-pump, beating-heart CABG pay much attention to the biventricular assist (BiVA). Nonetheless, much evidence also reveals that BiVA triggers an intense inflammatory response due to extracorporeal membrane lung and circuit line. Comparatively speaking, single left ventricular assist (LVA), with shorter circuit line, less priming volume and free of extracorporeal membrane lung, theoretically should reduce the inflammatory response and relative complications. As a result, aiming to the high-risk patients with severe left ventricle dysfunction, who need ECC assistance (BiVA or LVA), the investigators designed the randomized prospective study to evaluate: 1) the differences in myocardial injury as expressed by cardiac Troponin I(cTnI) and in inflammatory response by C-reactive protein (CRP), 2) the differences in the early postoperative outcomes including graft number, incidence of atrial fibrillation, in-hospital mortality and ICU stay.