Developing a risk prediction model for survival to discharge in cardiac arrest patients who undergo extracorporeal membrane oxygenation

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Highlights

  • We developed a prognostic model in patients underwent ECPR.

  • The ECPR score was a good indicator of survival to discharge.

  • This new scoring system might be helpful in ECPR management decision making.

Abstract

Background

Limited data are available on a risk model for survival to discharge after extracorporeal membrane oxygenation (ECMO)-assisted cardiopulmonary resuscitation (ECPR). We aimed to develop a risk prediction model for survival to discharge in cardiac arrest patients who undergo ECMO.

Methods

Between January 2004 and December 2012, 505 patients supported by ECMO were enrolled in a retrospective, observational registry. Among those, we studied 152 adult patients with in-hospital cardiac arrest. The primary outcome was survival to discharge. A new predictive scoring system, named the ECPR score, was developed to monitor survival to discharge using the β coefficients of prognostic factors from the logistic model, which were internally validated.

Results

In-hospital death occurred in 104 patients (68.4%). In multivariate logistic regression, age  66, shockable arrest rhythm, CPR to ECMO pump-on time  38 min, post-ECMO arterial pulse pressure > 24 mm Hg, and post-ECMO Sequential Organ Failure Assessment score  14 were independent predictors for survival to discharge. Survival to discharge was predicted by the ECPR score with a c-statistics of 0.8595 (95% confidence interval [CI], 0.80–0.92; p < 0.001) which was similar to the c-statistics obtained from internal validation (training vs. test set; c-statistics, 0.86 vs. 0.86005; 95% CI, 0.80–0.92 vs. 0.77–0.94). The sensitivity and specificity for prediction of survival to discharge were 89.6% and 75.0%, respectively, when the ECPR score was > 10.

Conclusions

The new risk prediction model might be helpful for decisions about ECPR management and could provide better information regarding early prognosis.

Introduction

Cardiopulmonary resuscitation (CPR) has traditionally been the treatment of choice for cardiopulmonary collapse and it has been developed and modified to achieve better survival. Unfortunately, previous studies revealed a low survival to discharge rate that ranged from 7 to 26% [1], [2], [3], [4], which declines rapidly if the duration of CPR exceeds 10 min [5], [6], [7]. Recently, extracorporeal cardiopulmonary resuscitation (ECPR) with a portable cardiopulmonary bypass system has been increasingly utilized to supply oxygenated blood in the absence of spontaneous cardiac pumping [8], [9]. Several observation studies have shown an improved survival rate compared to conventional CPR in patients with in-hospital cardiac arrest [10], [11]. However, to date, there have been no guidelines for the application of ECMO in the setting of CPR and the prognostic factors under ECPR have not been fully established in patients with in-hospital cardiac arrest. Therefore, we investigated the predictive risk factors for in-hospital death and developed a risk prediction model to better inform physicians of suitable candidates and their expected survival rate in cardiac arrest patients undergoing ECPR.

Section snippets

Study population

This was a retrospective, single-center, observational study of consecutive adult patients with in-hospital cardiac arrest who had ECPR at Samsung Medical Center between January 2004 and December 2012. This study received the Institutional Review Board approval and informed consent was waived. Clinical, laboratory, and outcome data were collected by a trained study coordinator using a standardized case report form. Additional information was documented by reviewing hospital records and

Baseline and procedural characteristics

Among 152 adult cardiac arrest patients who underwent ECPR, successful ECMO weaning was achieved in 67 patients (44.1%) and survival to discharge was identified in 48 patients (31.6%). The demographic patient data are shown in Table 1. There were no significant differences between non-survival and survival groups except for the diabetes. The initial arrest and procedural findings are shown in Table 2. A cardiogenic origin was the most common cause of cardiopulmonary resuscitation (n = 125, 82.2%)

Discussion

In our study, we investigated the risk factors predictive of survival and developed a new prognostic scoring system to predict survival to discharge for in-hospital cardiac arrest adult patients who underwent ECPR using a single-center registry for nine years. Old age, arrest rhythm of asystole, delayed ECMO pump-on, low initial pulse pressure, and poor initial SOFA score were independent predictors of in-hospital death. The ECPR score, which was developed using β coefficients of five

Funding source

None.

Conflict of interest

The authors declare no conflicts of interest. The authors of this manuscript have certified that they comply with the Principles of Ethical Publishing in the International Journal of Cardiology.

Acknowledgments

We appreciate the excellent statistical support of Seonwoo Kim, PhD, and Joonghyun Ahn, MS at the Samsung Biomedical Research Institute.

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