Cardiogenic shock: evolving definitions and future directions in management

Abstract

Cardiogenic shock (CS) is a complex and highly morbid entity conceptualised as a vicious cycle of injury, cardiac and systemic decompensation, and further injury and decompensation. The pathophysiology of CS is incompletely understood but limited clinical trial experience suggests that early and robust support of the failing heart to allow for restoration of systemic homoeostasis appears critical for survival. We review the pathophysiology, clinical features and trial data to construct a contemporary model of CS as a systemic process characterised with maladaptive compensatory mechanisms requiring prompt and appropriately tailored medical and mechanical support for optimal outcomes. We conclude with an algorithmic approach to acute CS incorporating clinical and haemodynamic data to match the patient's cardiac and systemic needs as a template for contemporary management.

Keywords: cardiogenic shock; heart failure; mechanical circulatory support; myocardial infarction; temporary circulatory support.

Figure 1

Conceptual algorithm for the management of cardiogenic shock (CS). The pathophysiology of CS is characterised by impaired cardiac output, SIRS, end-organ hypoperfusion and maladaptive compensatory mechanisms. Prevention of progressive cardiac and systemic compromise requires early recognition typically requiring right and left catheterisation and interruption of the vicious cycle by addressing underlying insults and initiation of mechanical circulatory support matched to the degree of clinical decompensation. Clinical indices such as CPI for LV function, PAPi for right ventricular function, and presence of malignant clinical features such as arrhythmia and hypoxaemia may help guide the decision for the most appropriate MSC modality. Bi-V, biventricular; CPI, Cardiac Power Index; LV, left ventricular; MCS, mechanical circulatory support; MI, myocardial infarction; PAPi, Pulmonary Artery Pulsatility Index; SIRS, systemic inflammatory response syndrome.

Figure 2

Causes of cardiogenic shock (adapted from Harjola et al [10]). ACS, acute coronary syndrome; MI, myocardial infarction.

Figure 3

Cardiac index (CI) and mean arterial pressure (MAP) correlation to Cardiac Power Index (CPI).