Clinical review: mechanical circulatory support for cardiogenic shock complicating acute myocardial infarction

Abstract

Acute myocardial infarction is one of the 10 leading reasons for admission to adult critical care units. In-hospital mortality for this condition has remained static in recent years, and this is related primarily to the development of cardiogenic shock. Recent advances in reperfusion therapies have had little impact on the mortality of cardiogenic shock. This may be attributable to the underutilization of life support technology that may assist or completely supplant the patient's own cardiac output until adequate myocardial recovery is established or long-term therapy can be initiated. Clinicians working in the intensive care environment are increasingly likely to be exposed to these technologies. The purpose of this review is to outline the various techniques of mechanical circulatory support and discuss the latest evidence for their use in cardiogenic shock complicating acute myocardial infarction.

Figure 1

Pictorial representation of intra-aortic balloon pump within the aorta, showing placement just distal to subclavian artery. Reprinted with permission from Maquet GmbH & Co. KG (Rastatt, Germany).

Figure 2

Diagrammatic representation of peripheral veno-venous (VV-ECMO) and peripheral veno-arterial (VA-ECMO) extracorporeal membrane oxygenation. Reprinted with permission from Maquet GmbH & Co. KG (Rastatt, Germany).

Figure 3

Simplified flow diagram of initiation of mechanical circulatory support. Patients requiring full mechanical circulatory support should be referred to experienced, high-volume centers. *See Table 4 for contraindications to mechanical circulatory support. ^†Inotrope score = doses of dopamine + dobutamine μg/kg per min + [(epinephrine + norepinephrine + isoproterenol μg/kg per min) × 100] + [milrinone μg/kg per min × 15]. AMI, acute myocardial infarction; APO, acute pulmonary edema; AR, aortic regurgitation; ECMO, extracorporeal membrane oxygenation; IABP, intra-aortic balloon pump; IPPV, invasive positive pressure ventilation; LVAD, left ventricular assist device; MCS, mechanical circulatory support.

Figure 4

Diagram of the TandemHeart percutaneous left ventricular assist device in situ in an adult. Reprinted with permission from CardiacAssist, Inc. (Pittsburgh, PA, USA), the manufacturer of this device.

Figure 5

Diagram demonstrating the Impella LP2.5 axial flow left ventricular assist device sitting across the aortic valve. Reprinted with permission from Abiomed (Aachen, Germany), the manufacturer of this device.