The Management of Cardiogenic Shock in Acute Myocardial Infarction: Conservative vs Aggressive Approach

Cardiogenic shock is a cardiac emergency condition defined as the inability of the heart to supply sufficient blood in order to meet the needs of tissue basal metabolism, even though the intravascular volume is sufficient. This condition occurs mainly in acute myocardial infarction. The incidence of cardiogenic shock in acute myocardial infarction remains relatively unchanged over the last 23 years despite significant advances in the management of patients have been achieved. A dilemma on what the best strategy is in managing patients still persists: should it be conservative or aggressive? The criteria of cardiogenic shock according to SHOCK trial include clinical and hemodynamic parameters such as systolic blood pressures of < 90 mmHg for 30 minutes prior to inotropic or vasopressor administration; a condition where intraaortic balloon pump (IABP) is required to maintain the systolic blood pressure of ³ 90 mmHg; evidence of decreased organ perfusion; and heart rate of ³ 60 bpm. The hemodynamic criteria include a pulmonary capillary wedge pressure of ³15 mmHg and an index cardiac output of £ 2.2/ min/ m2. Cardiogenic shock usually occurs as aresult of left ventricular failure associated with acute myocardial infarction with only < 40% of left ventricle mass involved in contraction. The main principle in the management of cardiogenic shock is to open the obstructed coronary vessels as soon as possible. It could be done either through thrombolysis or through invasive revascularization with percutaneous or surgical coronary intervention, popularly known as coronary artery bypass graft surgery (CABG). Various studies, both randomized and non-randomized, have supported more aggressive approach with early revascularization in the effort to increase patient life expectancy.