Short-term and long-term prognostic outcomes of patients with ST-segment elevation myocardial infarction complicated by profound cardiogenic shock undergoing early extracorporeal membrane oxygenator-assisted primary percutaneous coronary intervention

Abstract

Background

This study investigated the 30-day and long-term prognostic outcomes in patients with ST-segment elevation myocardial infarction (STEMI) complicated with profound cardiogenic shock (CS) undergoing early routine extracorporeal membrane oxygenator (ECMO)-assisted primary percutaneous coronary intervention (PCI).

Methods

Between December 2005 and December 2014, 65 consecutive STEMI patients with profound CS underwent routine ECMO-supported primary PCI.

Results

The incidences of acute pulmonary edema, respiratory failure with requirement of mechanical ventilatory support upon presentation, and 30-day mortality rate were 100%, 95.4%, and 43.1%, respectively. The duration of hospitalization, mean long-term follow-up, and survival rate were 32.1 ± 53.1 (days), 733.6 ± 986.7 (days), and 32.3%, respectively. The mean APACHE score (32.6 ± 8.3 vs. 28.5 ± 7.5), peak serum creatinine level (4.3 ± 2.4 vs. 1.7 ± 1.2 mg/dL), incidences of failed ECMO weaning (57.1% vs. 0%), successful ECMO weaning but in-hospital death (40.0% vs. 0%) were significantly lower in 30-day survivors than those in non-survivors (all p < 0.05), whereas final thrombolysis in myocardial infarction (TIMI)-3 flow [53.6% vs. 91.9%] showed an opposite pattern compared to that of APACHE score in the two groups (p < 0.02). Multivariate analysis demonstrated that unsuccessful reperfusion, failed ECMO weaning, and peak creatinine level were independent predictors of 30-day mortality (all p < 0.01).

Conclusions

Early ECMO-supported primary PCI in STEMI patients with profound CS was feasible as a life-saving strategy with acceptable 30-day and long-term prognostic outcomes.

Introduction

Acute myocardial infarction (AMI) had been identified as the leading cause of death in patients hospitalized for cardiovascular diseases [1], [2], [3]. However, with the improvement of pharmacological treatment [4], [5], [6], advanced technique of percutaneous coronary intervention (PCI) [7], [8], [9], shortening of door-to-balloon time for patients with acute ST-segment elevation MI (STEMI) [10], [11], flexible utilization of mechanical device for circulatory support [12], [13], [14] in situations of unstable hemodynamics, and active cardiac rehabilitation programs [15], [16], reperfusion therapy has remarkably decreased the mortality rate of patients with STEMI [4], [17], [18] as compared to that in the pre-reperfusion era worldwide [19].

Nevertheless, the in-hospital mortality rate of the subgroup of STEMI patients complicated by cardiogenic shock (CS) is still unacceptably high despite reperfusion therapy [14], [20], [21] with intra-aortic balloon pump (IABP) support and the long-term outcome remains unfavorable [14], [22], [23]. Indeed, our previous study has further demonstrated that the incidence of profound shock in the setting of CS was greater than 21% and that the clinical outcome was extremely poor for patients with STEMI complicated by profound CS [12], [14]. Therefore, reduction of short-term and long-term mortality for STEMI patients with profound CS undergoing primary PCI is the real therapeutic goal for this subgroup of patients.

Growing data have revealed that extracorporeal membrane oxygenator (ECMO)-assisted primary PCI appears to be an effective modality for improving in-hospital survival for patients with STEMI complicated by CS, especially in those with profound CS undergoing primary PCI [14], [24], [25], [26]. However, the sample sizes in these studies [14], [24], [25], [26] were relatively small. Besides, the long-term outcome of patients with profound CS undergoing primary PCI has not been reported. Moreover, the fact that ECMO support was highly selective for patients in most of these studies [24], [25], [26] is not consistent with real-world clinical practice.

Kaohsiung Chang Memorial Hospital is a tertiary medical center for providing patients with critical care in various disease settings, including those with STEMI in extremely unstable condition. A program for ECMO-support primary PCI for eligible patients with STEMI complicated by profound CS has been started at the institute since 2005. Our study was a descriptive observational design. Thus, in this study, we could only investigate the characteristics that were related with a poor prognosis in patients with STEMI complicated by profound CS undergoing early routine ECMO-supported primary PCI.