Myocardial protection with glucose-insulin potassium in patients with acute coronary syndromes requiring coronary artery bypass grafting: A case series

Emergent cardiac surgery in patients with acute coronary syndrome (ACS) is always a challenging task for surgeons, anesthesiologists and patients. As “time is muscle,” early revascularization by percutaneous coronary intervention (PCI) has been largely advocated to salvage myocardial ischemic cells. In cases judged not suitable for PCI, on-pump coronary artery bypass grafting (CABG) is indicated with cardioplegic arrest and eventually anesthetic preconditioning to enhance myocardial protection. In these high-risk emergent procedures, adjuvant interventions to cardioplegic arrest are aimed to maximize the chance of cardiac functional recovery. Although the infusion of glucose-insulin-potassium (GIK) has demonstrated interesting cardioprotective effects in animal models of myocardial ischemia and in patients undergoing elective cardiac surgery, this cardioprotective strategy has not yet been adopted largely and has been ignored so far in emergent myocardial revascularization procedures. In this case series, we describe the effects of GIK on left ventricular performance assessed by transesophageal echocardiography in four patients with ACS who required emergent CABG surgery. The GIK solution of 20 g glucose, 20 UI insulin and 10 mEq potassium chloride was infused twice over 30 min, first after anesthesia induction and later after aortic unclamping. The systolic performance was assessed after anesthesia induction and after each GIK infusion using the 3D left ventricular ejection fraction, as well as the global longitudinal and circumferential strain. The diastolic function was assessed based on mitral inflow patterns (E-and A-waves) as well as flow propagation velocity.