Response by Bartos and Yannopoulos to Letter Regarding Article, “Improved Survival With Extracorporeal Cardiopulmonary Resuscitation Despite Progressive Metabolic Derangement Associated With Prolonged Resuscitation”
Authors: Jason A. Bartos, Demetris Yannopoulos
Journal: Circulation (2020)

In Response:We appreciate the letter from Den Uil et al regarding our research article describing improved survival with use of extracorporeal cardiopulmonary resuscitation (ECPR) in patients with refractory ventricular fibrillation/ventricular tachycardia out-of-hospital cardiac arrest. 1 This study examined a cohort of 160 consecutive patients treated with the University of Minnesota ECPR protocol in comparison with patients from the amiodarone arm of the ALPS (Amiodarone, Lidocaine, or Placebo Study).The ALPS cohort included shock-refractory ventricular fibrillation/ ventricular tachycardia patients treated with standard advanced cardiac life support provided by highly trained emergency medical services.The key finding of this study was a significantly higher rate of neurologically favorable survival in patients treated with ECPR at all CPR durations <60 minutes with an overall odds ratio of 20.80 when all patient and arrest characteristics were included in the logistic regression model.However, the rate of survival declined over time, with 2.5% decrease in survival per minute of professional CPR beyond 30 minutes.There were no survivors with favorable neurological status in the ALPS group with CPR duration ≥40 minutes, consistent with previously published studies. 2 In comparison, the ECPR group had 25% neurologically favorable survival even after prolonged CPR.It is important that even at the shortest CPR times observed in the ECPR cohort of 20 to 29 minutes, survival was significantly higher in the ECPR group compared with ALPS, suggesting that ECPR enhances survival even without corrections for CPR duration.Prospective studies are underway, including multiple randomized clinical trials (NCT03880565, NCT03101787, and NCT01605409).The ARREST trial (Advanced Reperfusion Strategies for Refractory Ventricular Fibrillation Out-of-Hospital Cardiac Arrest) has concluded.The results will be published shortly.As noted by Den Uil et al, a few patients achieved return of spontaneous circulation before arrival at the cardiac catheterization laboratory, resulting most often in use of an intra-aortic balloon pump for hemodynamic support because these patients had ongoing cardiogenic shock on arrival.Previously published data demonstrated that 13% of patients transported achieved return of spontaneous circulation before arrival. 3The role of intra-aortic balloon pump in this population remains untested.Patients with cardiogenic shock after prolonged cardiac arrest have not been studied rigorously, and they constitute a small portion of this cohort.Coronary artery disease is highly prevalent in this population.As previously published, 3 of 4 patients have at least 1 critical stenosis and 2 of 3 have acute thrombotic lesions. 4This is distinct from the results of the COACT trial (Coronary Angiography After Cardiac Arrest Without ST-Segment Elevation), which included resuscitated patients and excluded patients with signs of cardiogenic shock. 5 The median time from arrest to return of spontaneous circulation was 15 minutes.As such, the 2 populations are clinically different.Patients with refractory