Cardiac Arrest Prior to Venoarterial Extracorporeal Membrane Oxygenation: Risk Factors for Mortality

Objectives: Mortality after cardiac arrest remains high despite initiation of venoarterial extracorporeal membrane oxygenation. We aimed to identify pre-venoarterial extracorporeal membrane oxygenation risk factors of 90-day mortality in patients with witnessed cardiac arrest and with greater than or equal to 1 minute of cardiopulmonary resuscitation before venoarterial extracorporeal membrane oxygenation. The association between preimplant variables and all-cause mortality at 90 days was analyzed with multivariable logistic regression. Design: Retrospective observational cohort study. Setting: Tertiary medical center. Patients: Seventy-two consecutive patients with cardiac arrest prior to venoarterial extracorporeal membrane oxygenation cannulation. Interventions: None. Measurements and Main Results: Median age was 56 years (interquartile range, 43-56 yr), 75% (n = 54) were men. Out-of-hospital cardiac arrest occurred in 12% (n = 9) of the patients. Initial cardiac rhythm was nonshockable in 57% (n = 41) and shockable in 43% (n = 31) of patients. Median cardiopulmonary resuscitation duration was 21 minutes (interquartile range, 10-73 min; range, 1-197 min]. No return of spontaneous circulation was present in 64% (n = 46) and postarrest cardiogenic shock in 36% (n = 26) of the patients at venoarterial extracorporeal membrane oxygenation cannulation. Median duration of venoarterial extracorporeal membrane oxygenation was 5 days (interquartile range, 2-12 d). The 90-day overall mortality and in-hospital mortality were 57% (n = 41), 53% (n = 38) died during venoarterial extracorporeal membrane oxygenation, and 43% (n = 31) were successfully weaned. All survivors had Cerebral Performance Category score 1-2 at discharge to home. Multivariable logistic regression analysis identified initial nonshockable cardiac arrest rhythm (odds ratio, 12.2; 95% CI, 2.83-52.7; p = 0.001), arterial lactate (odds ratio per unit, 1.15; 95% CI, 1.01-1.31; p = 0.041), and ischemic heart disease (7.39; 95% CI, 1.57-34.7; p = 0.011) as independent risk factors of 90-day mortality, whereas low-flow duration, return of spontaneous circulation, and age were not. Conclusions: In 72 patients with cardiac arrest before venoarterial extracorporeal membrane oxygenation initiation, nonshockable rhythm, arterial lactate, and ischemic heart disease were identified as independent pre-venoarterial extracorporeal membrane oxygenation risk factors of 90-day mortality. The novelty of this study is that the metabolic state, expressed as level of lactate just before venoarterial extracorporeal membrane oxygenation initiation seems more predictive of outcome than cardiopulmonary resuscitation duration or absence of return of spontaneous circulation.