[Perioperative Management of Cardiac Surgery in Patients with Preoperative Heart Failure]

The lower preoperative left ventricular ejection fraction( LVEF), the more postoperative death. The perioperative management for cardiovascular patients with heart failure (LVEF<40%) is of great importance in cardiac surgery. The failing heart is characterized by intracellular Ca2+ handling abnormalities during excitation/contraction coupling( i.e., less amount of cytosolic Ca2+ recruitment in systole and insufficient cytosolic Ca2+ extrusion in diastole), which are caused by increased reverse-mode Na+/ Ca2+ exchange activity and abnormal sarcoplasmic reticular Ca2+ channels (ryanodine receptors) and Ca2+ pumps (adenosine triphosphatase:ATPases). Myocardial ischemia/reperfusion (I/R) damage is characterized by intracellular acidosis followed by Ca2+ overload during I/R. The failing/hypertrophied myocardium has a low coronary vascular density, leading to low oxygen supply to the cardiomyocyte, and is vulnerable to Ca2+ load during I/R. Based on those abnormalities, hypothermic cardioplegia is recommended to suppress myocardial oxygen demand in open heart surgery for patients with heart failure(low LVEF). Optimal medical managements using adrenergic stimulators, vasodilators, antiarrhythmics, cardiac pacing, NO inhalation, or myocardial Ca2+ sensitizers under preload adjustment may be essential for hemodynamic improvement of postoperative low cardiac output syndrome. On a case-bycase basis, mechanical circulatory support systems should be utilized before the development of multiple organ failure.