Impact of age on the outcomes of extracorporeal cardiopulmonary resuscitation: analysis using inverse probability of treatment weighting

Abstract

Objectives: Patient selection is crucial to improving the outcomes of extracorporeal cardiopulmonary resuscitation (ECPR). However, ECPR's efficacy with older patients remains unknown.

Methods: We reviewed patients who underwent extracorporeal membrane oxygenation (ECMO) for refractory cardiac arrest from January 2006 to December 2018. Exclusion criteria were age <18 years, cannulation failure and ECMO applied at another hospital. We divided patients into 2 groups with an age cut-off of 66 years, using the Contal and O'Quigley method for overall survival. We performed inverse probability of treatment weighting (IPTW) between the 2 groups and set the primary outcome as overall survival.

Results: We included 318 patients in our study (≤66 years, n = 199; >66 years, n = 119). Before IPTW, we observed that the older group had a higher frequency of diabetes, hypertension, and myocardial infarction. In the young group, more patients had out-of-hospital cardiac arrest as compared with the older group. The hospital mortality rate was 55% (48.7% in the young group, 65.5% in the older group; P = 0.004). In the multivariable analysis after IPTW, the older group showed worse outcomes in overall survival [hazard ratio (HR) = 2.02; 95% confidence interval (CI), 1.50-2.70; P < 0.001] and neurological outcomes at discharge (odds ratio = 2.95; 95% CI, 1.69-5.14; P = <0.001). ECMO insertion during catheterization (HR = 0.57; 95% CI, 0.36-0.90; P = 0.015) and recovery of spontaneous circulation before pump-on (HR = 0.67; 95% CI, 0.50-0.89; P = 0.007) were positive predictors, but initial asystole rhythm, non-cardiac cause (HR = 2.39; 95% CI, 1.59-3.61; P < 0.001), out-of-hospital cardiac arrest (HR = 1.86; 95% CI, 1.24-2.79; P = 0.003) and prolonged cardiopulmonary resuscitation to pump-on time (HR = 1.01; 95% CI, 1.01-1.02; P < 0.001) were negative predictors for overall survival.

Conclusions: Older patients who had ECPR had significantly worse survival and neurological outcomes. For patients older than age 66 years, more careful patient selection is critically important for improving the efficacy of ECPR.

Keywords: Extracorporeal cardiopulmonary resuscitation; Inverse probability of treatment weighting; Neurological outcome; Old age; Survival.