The role of acute circulatory support in ST-segment elevation myocardial infarction complicated by cardiogenic shock

Abstract

In the setting of ST-segment elevation myocardial infarction (STEMI) complicated by cardiogenic shock, three primary treatment objectives include providing circulatory support, ventricular unloading, and restoring myocardial perfusion. In addition to primary percutaneous coronary intervention, each of these three objectives can be achieved with appropriate use of an acute mechanical circulatory support (AMCS) pump. Over the past decade, utilization of percutaneously-delivered AMCS devices including the Impella axial-flow catheter, TandemHeart left atrial-to-femoral artery bypass system, and veno-arterial extracorporeal membrane oxygenation (VA-ECMO) has grown exponentially. In this review, we will discuss the hemodynamic impact of each AMCS device and clinical data surrounding their use in the setting of STEMI complicated by cardiogenic shock.

Venoarterial Extracorporeal Membrane Oxygenation in Cardiogenic Shock: Lifeline of Modern Day CICU

“…It reduces afterload, increases stroke volume, optimizes coronary flow, and decreases oxygen consumption 27 (Figure 2A). 28,29 However, a meta-analysis reported no differences in short-term or long-term mortality in CS patients supported with IABP. 30 TandemHeart is a percutaneous continuous-flow centrifugal pump providing circulatory support of up to 5 L/min, but it requires trans-septal puncture, as it is inserted into the femoral vein and advanced across the interatrial septum into the left atrium.…”

“…7,31 This device unloads the left atrium, ultimately decreasing LV end-diastolic volumes. 16,29 Thiele et al looked at patients who were randomized to IABP or TandemHeart and found greater improvements in cardiac power, cardiac index, pulmonary arterial pressure, and pulmonary capillary wedge pressure but had similar 30-day mortality (43% vs 45%, P = .86). 32 Another study retrospectively looked at patients referred for TandemHeart and found that survival was significantly influenced by implant indication with 23.8% surviving in bridge to recovery versus 51% in bridge to left ventricular assist device (LVAD) or surgery ( P = .04).…”

“…Venoarterial ECMO increases mean arterial pressures (MAPs) and afterload as well as increases LV systolic and diastolic pressures as illustrated in Figures 2 and 3. 28,29 Unfortunately, this can contribute to an increase in LVEDP. If patients have a significantly reduced ejection fraction at baseline, VA-ECMO can lead to increased LV wall stress, oxygen demand, and ultimately slow myocardial recovery.…”

“…This device ultimately unloads the LV by decreasing end-diastolic volume and pressure. 16,29 Contrary to IABP, Impella does not require electrocardiogram or arterial waveform triggering, allowing its use in tachyarrhythmias or electromechanical dissociation. 2 Two different trials that investigated 2 versions of Impella (Impella 2.5 and Impella Cardiac Power [CP]) compared to IABP failed to demonstrate a mortality benefit; 46% in both Impella 2.5 and IABP and 50% versus 46% for Impella CP versus IABP, respectively.…”

“…Figures 2C represents the hemodynamic effects of VA-ECMO without LV venting. 28,29 Due to this milieu of pressure changes, close monitoring of LVEDP is required during VA-ECMO.…”