Extracorporeal cardiopulmonary resuscitation success - System or selection?

With great interest we read the article by Bosson et al. describing the implementation of a multicentre extracorporeal CPR (ECPR) program for out-of-hospital cardiac arrest (OHCA) in the Los Angeles region.1Bosson N. Kazan C. Sanko S. Abramson T. Eckstein M. Eisner D. et al.Implementation of a regional extracorporeal membrane oxygenation program for refractory ventricular fibrillation out-of-hospital cardiac arrest.Resuscitation. 2023; 109711Google Scholar The success of implementation of an ECPR program can be judged by its clinical results, and the authors deserve praise for achieving 27% survival with favourable neurological outcome. We recently published the INCEPTION trial,2Suverein M.M. Delnoij T.S.R. Lorusso R. Brandon Bravo Bruinsma G.J. Otterspoor L. Elzo Kraemer C.V. et al.Early Extracorporeal CPR for Refractory Out-of-Hospital Cardiac Arrest.N Engl J Med. 2023; 388: 299-309Crossref PubMed Scopus (28) Google Scholar which some consider an example of a flawed implementation of a multicentre ECPR program, most importantly due to failure to achieve timely successful cannulation.3Bartos J.A. Yannopoulos D. Starting an Extracorporeal cardiopulmonary resuscitation Program: Success is in the details.Resuscitation. 2023; 187109792Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar However, we noticed numerous similarities between our own and Bosson’s experience. Alike Bosson et al., we selected state-of-the-art STEMI centres with operational ECMO programs. All centres had protocols for multidisciplinary collaboration around ECPR with free choice of cannulation method. In addition, we also performed regular simulation training and issued continuous ECPR awareness campaigns amongst EMS services. Most striking however, are the remarkable similarities between the time intervals from cardiac arrest until the eventual start of ECMO which also can be seen as quality indicators for system performance (Table 1).Table 1Comparison of time intervals between patients assigned to ECPR in the INCEPTION-trial and the Los Angeles ECPR experience.1Bosson N. Kazan C. Sanko S. Abramson T. Eckstein M. Eisner D. et al.Implementation of a regional extracorporeal membrane oxygenation program for refractory ventricular fibrillation out-of-hospital cardiac arrest.Resuscitation. 2023; 109711Google Scholar Data from the INCEPTION trial have partly been published before.2Suverein M.M. Delnoij T.S.R. Lorusso R. Brandon Bravo Bruinsma G.J. Otterspoor L. Elzo Kraemer C.V. et al.Early Extracorporeal CPR for Refractory Out-of-Hospital Cardiac Arrest.N Engl J Med. 2023; 388: 299-309Crossref PubMed Scopus (28) Google Scholar Data are numbers (percentage), mean (SD) or median (IQR).INCEPTIONLos AngelesPatients with ≥3 defibrillations59/70 (84.3%)11/11 (100%)Survival to ICU Admission*44/52 (84.6%)9/11 (81.8%)Time on ECMO (days)1.2 (1.7)2.4 (2.2)EMS response time (min)8 (5–10)8 (6–10)EMS scene time (min)22 (18–27)19 (16–25)Transport time (min)15 (7–25)16 (12–18)Time from ED arrival to ECMO (min)34 (24–40)31 (16–54)Time from cardiac arrest to ECMO (min)74 (63–87)76 (53–94)Survival with favourable neurology \dag5/52 (9.6%)*3/11 (27.3%)*Only patients where ECPR was initiated; \dag INCEPTION: 30-days after arrest, LA: at hospital discharge. Open table in a new tab *Only patients where ECPR was initiated; \dag INCEPTION: 30-days after arrest, LA: at hospital discharge. In the accompanying editorial, Bartos and Yannopoulos emphasize that optimal system performance is mandatory to achieve excellent results with ECPR for OHCA.3Bartos J.A. Yannopoulos D. Starting an Extracorporeal cardiopulmonary resuscitation Program: Success is in the details.Resuscitation. 2023; 187109792Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar However, the time intervals reported by Bosson et al. suggest that their good clinical results may be the result of patient selection, rather than of system performance. Selection criteria excluded patients rapidly progressing from ventricular fibrillation to PEA or asystole and patients with dismal biochemical parameters, reserving ECPR for patients with a highly favourable metabolic profile in which time to ECMO may be less critical. Here lies a vast difference with the INCEPTION trial that selected patients based on more limited, clinical information (age, witnessed arrest, immediate BLS and shockable rhythm). It seems clear that pragmatic patient selection impairs the outcome of ECPR, even in an excellently functioning system.4Belohlavek J. Smalcova J. Rob D. Franek O. Smid O. Pokorna M. et al.Effect of Intra-arrest Transport, Extracorporeal Cardiopulmonary Resuscitation, and Immediate Invasive Assessment and Treatment on Functional Neurologic Outcome in Refractory Out-of-Hospital Cardiac Arrest: A Randomized Clinical Trial.JAMA. 2022; 327: 737-747Crossref PubMed Scopus (106) Google Scholar Probably partly due to their strict selection criteria, Bosson et al. identified only 11 ECPR candidates in an area with 4 million inhabitants over a 2-year timespan, resulting in 3 survivors. Although the survival rate is encouraging, it may be argued that absolute revenues do not (yet) seem to be proportional to the resources that were allocated to the program. ECPR for refractory OHCA is established as a promising rescue option that can make a substantial difference in seasoned systems.5Yannopoulos D. Bartos J. Raveendran G. Walser E. Connett J. Murray T.A. et al.Advanced reperfusion strategies for patients with out-of-hospital cardiac arrest and refractory ventricular fibrillation (ARREST): a phase 2, single centre, open-label, randomised controlled trial.Lancet. 2020; 396: 1807-1816Abstract Full Text Full Text PDF PubMed Scopus (336) Google Scholar While the results from the Los Angeles region confirm that a clinically relevant survival rate can be achieved with ECPR for OHCA in selected cases, they also emphasize the stubbornness of the implementation of an ECPR system that consistently achieves a time from arrest to ECMO below 60 minutes. Whether ECPR can eventually evolve into an effective, sustainable, commonplace therapy in refractory OHCA remains to be answered. As such, we look forward to future results from the Los Angeles group to see whether they will be able to increase case-load and improve system performance while preserving their laudable clinical outcome. Roberto Lorusso reports financial support was provided by Abiomed Europe GmbH. Marcel van de Poll reports financial support was provided by Getinge AB. Roberto Lorusso reports a relationship with Xenios AG that includes: board membership. Anina F. van de Koolwijk: Writing – original draft, Writing – review & editing, Conceptualization. Johannes F.H. Ubben: Conceptualization, Formal analysis, Writing – review & editing. Martje M. Suverein: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Project administration, Resources, Software, Validation, Writing – review & editing. Roberto Lorusso: Conceptualization, Investigation, Methodology, Supervision, Writing – original draft, Writing – review & editing. Marcel C.G. van de Poll: Conceptualization, Data curation, Formal analysis, Funding acquisition, Investigation, Methodology, Project administration, Resources, Software, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing. The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Roberto Lorusso reports financial support was provided by Abiomed Europe GmbH. Marcel van de Poll reports financial support was provided by Getinge AB. Roberto Lorusso reports a relationship with Xenios AG that includes: board membership.