CARDIOGENIC SHOCK DUE TO END-STAGE HEART FAILURE AND ACUTE MYOCARDIAL INFARCTION: CHARACTERISTICS AND OUTCOME OF TEMPORARY MECHANICAL CIRCULATORY SUPPORT

Background: Mechanical circulatory support (MCS) is increasingly used in cardiogenic shock, but outcomes may differ between patients with acute myocardial infarction (AMI) or end-stage heart failure (ESHF). This study aimed to describe the characteristics of patients with cardiogenic shock due to AMI and ESHF. Methods: Single-center study of consecutive patients with cardiogenic shock due to AMI (n=26) and ESHF (n=42) who underwent MCS (extracorporeal life support, Impella or temporary ventricular assist devices). Arterial and venous O-2 content and CO2 tension (PCO2), O-2-hemoglobin affinity (P50) were measured. Veno-arterial difference in PCO2/arterio-venous difference in O-2 content ratio was derived. Acid-base balance was characterized by the Gilfix method. MCS-related complications that required intervention or surgery were collected. Results: Patients with ESHF had lower ejection fraction, higher right and left-sided filling pressures, pulmonary artery pressure and vascular resistance, lower oxygen delivery (DO2) compared with AMI, which was not fully compensated by the increased hemoglobin P50. As a result, patients with ESHF had higher veno-arterial difference in PCO2 relative to arterio-venous difference in O-2 content. Despite greater anerobic metabolism, patients with ESHF had less severe metabolic acidosis and base deficit compared with AMI, predominantly due to differences in strong ions. Conclusion: The cardiogenic shock phenotype in ESHF was distinct from AMI, characterized by higher filling and pulmonary artery pressures, lower DO2, greater anaerobic metabolism but less severe metabolic acidosis.