Efficacy of veno-arterial extracorporeal membrane oxygenation in acute myocardial infarction with cardiogenic shock

Abstract

Aim

We analyzed the results of acute myocardial infarction (AMI) complicated by cardiogenic shock (CS) necessitating extracorporeal membrane oxygenation (ECMO), and investigated for the associated risk factors for poor clinical outcomes.

Methods

We retrospectively reviewed the medical records of 27 patients who required ECMO for AMI associated with CS between April 2006 and July 2010. Mean age was 63.7 ± 11.0 (range: 45–81) years, and there were 16 males (59.3%).

Results

The mean duration of ECMO support was 30.2 ± 30.1 (range: 1–141) h. Cardiopulmonary resuscitations (CPR) were performed in 21 patients (77.8%) before ECMO initiation. Twenty-two patients (81.5%) were successfully weaned off ECMO, and 16 patients (59.3%) survived to discharge. The 30-day mortality was 37.0% (10/27 patients). Complications developed in 17 patients (63.0%: pneumonia in 10 patients, acute renal failure in 10 patients, massive bleeding in 4 patients, and thromboembolic event in 1 patient). The period between CPR initiation and ECMO commencement was a significant risk factor for ECMO weaning failure. High pre-ECMO serum lactate level was identified as a significant risk factor for poor survival on univariated and multivariated analysis.

Conclusion

ECMO support could improve survival in patients who suffer AMI associated with CS, and early ECMO initiation yields better outcomes (successful ECMO weaning).

Introduction

Over the past 15 years, the 30-day mortality and overall complications of acute myocardial infarction (AMI) have been substantially reduced by the use of coronary reperfusion therapy.1, 2, 3 However, cardiogenic shock (CS) remains a leading cause of death in patients hospitalized with AMI.⁴ Although intra-aortic balloon pump (IABP) counterpulsation remains the first choice of mechanical circulatory support and plays a certain beneficial role in the management of CS,5, 6 mortality associated with AMI-related CS is expected to rise in patients who experience cardio-pulmonary arrest and receive cardio-pulmonary resuscitation (CPR).

Extracorporeal membrane oxygenation (ECMO) provides cardiopulmonary support and has been shown to be effective for the treatment of refractory pulmonary insufficiency,⁷ and for providing cardiac assistance in patients with severe cardiac failure.8, 9, 10 It has recently been reported that ECMO improves the outcome of cardiac resuscitation in patients with CS or arrest due to ischemic heart disease.11, 12 Little information, however, is available on the efficacy of ECMO for the management of AMI associated with CS.

In this study, we focused on a group of patients initially presented with AMI complicated by CS unresponsive to conventional treatment, and required ECMO support over a 5-year period. The aims of this study were to analyze the results of AMI complicated with CS necessitating ECMO, and to investigate for the associated risk factors for poor clinical outcomes.