Mechanical circulatory support in cardiogenic shock

Abstract

Cardiogenic shock is a complex and diverse pathological condition characterized by reduced myocardial contractility. The goal of treatment of cardiogenic shock is to improve abnormal hemodynamics and maintain adequate tissue perfusion in organs. If hypotension and insufficient tissue perfusion persist despite initial therapy, temporary mechanical circulatory support (t-MCS) should be initiated. This decade sees the beginning of a new era of cardiogenic shock management using t-MCS through the accumulated experience with use of intra-aortic balloon pump (IABP) and venoarterial extracorporeal membrane oxygenation (VA-ECMO), as well as new revolutionary devices or systems such as transvalvular axial flow pump (Impella) and a combination of VA-ECMO and Impella (ECPELLA) based on the knowledge of circulatory physiology. In this transitional period, we outline the approach to the management of cardiogenic shock by t-MCS. The management strategy involves carefully selecting one or a combination of the t-MCS devices, taking into account the characteristics of each device and the specific pathological condition. This selection is guided by monitoring of hemodynamics, classification of shock stage, risk stratification, and coordinated management by the multidisciplinary shock team.

Fig. 1

PV loops under various t-MCS conditions for the treatment of cardiogenic shock. Illustrations of PV loops in cardiogenic shock or cardiogenic shock with several MCS support conditions. A In cardiogenic shock, acute decrease of Ees shifts the PV loop rightward and reduces the stroke volume and LV pressure. B–H PV loops under various support conditions: IABP, VA-ECMO, VA-ECMO + IABP, Impella partial support, Impella total support, ECPELLA total support, and ECPELLA total unloading. PV loop pressure–volume loop, t-MCS temporary mechanical circulatory support, CGS cardiogenic shock, IABP intra-aortic balloon pump, VA-ECMO venoarterial extracorporeal membrane oxygenation, ECPELLA VA-ECMO + Impella, Ea effective arterial elastance, Ees end-systolic elastance, SV stroke volume, PVA pressure‒volume area, EDP end-diastolic pressure, EDPVR end-diastolic pressure‒volume relation, ESPVR end-systolic pressure‒volume relation

Fig. 2

The impact of aortic pressure on ECPELLA-supported PV loop. In cardiogenic shock condition (A), VA-ECMO markedly increases total systemic flow, while loading LV and increasing PVA (B). Addition of Impella to VA-ECMO decreases PVA (C). Further addition of a vasodilator that decreases blood pressure further reduces PVA markedly, and further increases total systemic flow (D). The simulation was conducted using our electrical model reported previously [33]. The cardiovascular parameters employed for the simulation are depicted in the right column. MCS mechanical circulatory support, VA-ECMO venoarterial extracorporeal membrane oxygenation, ECPELLA combination of VA-ECMO and Impella, AOP aortic pressure, LAP left atrial pressure, LVP left ventricular pressure, LVCO left ventricular cardiac output, PV pressure‒volume, PVA pressure‒volume area, LV-E_es left ventricular end-systolic elastance, RV-E_es right ventricular end-systolic elastance, EDPVR end-diastolic pressure–volume relationship, V₀ the volume intercept of end-systolic pressure volume relationship of LV, SBV stressed blood volume, SVR systemic vascular resistance, PVR pulmonary vascular resistance

Fig. 3

SCAI cardiogenic shock-classification. This figure was modified from Fig. 4 of the article. “SCAI SHOCK Stage Classification Expert Consensus Update: A Review and Incorporation of Validation Studies: This statement was endorsed by the American College of Cardiology (ACC), American College of Emergency Physicians (ACEP), American Heart Association (AHA), European Society of Cardiology (ESC) Association for Acute Cardiovascular Care (ACVC), International Society for Heart and Lung Transplantation (ISHLT), Society of Critical Care Medicine (SCCM), and Society of Thoracic Surgeons (STS) in December 2021 [56]

Fig. 4

Protocol of selection and escalation of temporary mechanical circulatory support. CAG cardiogenic shock, IABP intra-aortic balloon pumping, ROSC return of spontaneous circulation, VA-ECMO venoarterial extracorporeal membrane oxygenation, ECPELLA combination of VA-ECMO and Impella, LVEF left ventricular ejection fraction, LVEDP left ventricular end-diastolic pressure, CPO Cardiac power output, PCI percutaneous coronary intervention, PAC pulmonary artery catheter, VT ventricular tachycardia, Vf ventricular fibrillation, sBP systolic blood pressure, mBP mean blood pressure, CCU cardiovascular care unit

Fig. 5

Protocol of weaning of temporary mechanical circulatory support. MCS mechanical circulatory support, VA-ECMO venoarterial extracorporeal membrane oxygenation, ECPELLA combination of VA-ECMO and Impella, LV left ventricular, MAP mean arterial pressure, PAWP pulmonary artery wedge pressure, PA pulmonary artery, RV right ventricular, LV left ventricular, RAP right atrial pressure, PAPi pulmonary artery pulsatility index, VAD ventricular assist device, LVOT-VTI left ventricular outflow tract velocity time integral, CPO cardiac power output