Scoring the Importance of Patient Selection in Extracorporeal Cardiopulmonary Resuscitation and Non‐Shockable Rhythm Cardiac Arrest: The START‐ECPR Score

Extracorporeal cardiopulmonary resuscitation (ECPR) has emerged as an advanced resuscitative technique in the setting of out‐of‐hospital cardiac arrest that incorporates venoarterial extracorporeal membrane oxygenation to provide circulatory support in patients with refractory cardiac arrest. ¹ While ECPR holds promise in improving outcomes for selected patient populations, its application requires significant resources and specialized expertise, necessitating clear criteria to optimize patient selection and resource use. Recent advances in ECPR have further shaped its role in resuscitative medicine. ² Innovative developments in cannulation techniques and configurations have improved the speed and safety of ECPR initiation. Additionally, advancements in portable extracorporeal membrane oxygenation devices have enhanced the feasibility of prehospital ECPR implementation, expanding the potential window for effective intervention. ³ The integration of real‐time hemodynamic monitoring and the use of biomarkers to assess organ perfusion have also contributed to more precise patient management during ECPR. Furthermore, the evolution of postresuscitation care protocols, including targeted temperature management and optimized anticoagulation strategies, has been associated with better neurologic outcomes in ECPR‐treated patients.

The article published in this issue of the Journal of the American Heart Association (JAHA) by Kawauchi et al, ⁴ which presents a meticulous derivation of the Clinical Prediction Score for Initial Non‐shockable Rhythm Patients Receiving Extracorporeal Cardiopulmonary Resuscitation for Out‐of‐Hospital Cardiac Arrest (START‐ECPR) designed to predict survival outcomes in patients undergoing ECPR after out‐of‐hospital cardiac arrest with nonshockable rhythms, represents a significant contribution to the field of resuscitative medicine, particularly in its focus on an often‐overlooked patient subset. The authors have commendably used a large observational cohort from a national registry, using contemporary statistical methodologies to develop a score that includes 3 readily accessible clinical predictors: shockable rhythm or pulseless electrical activity at hospital arrival, transient return of spontaneous circulation before hospital arrival, and signs of life at hospital arrival. The simplicity and immediate applicability of these variables enhance the score's potential utility in emergent clinical decision making, where time and accuracy are of the essence. For example, the high specificity of the START‐ECPR, with mortality rates of 91.7% and poor neurologic outcomes at 95% when all positive indicators are absent, has profound implications for clinical decision making. Such degree of specificity for poor outcomes underscores the score's potential to inform resource allocation decisions, particularly concerning the initiation of extracorporeal membrane oxygenation in resource‐constrained settings.

Despite the strengths of the START‐ECPR, there are important limitations that were candidly addressed by the authors. Strict exclusion criteria, such as those with unknown presenting rhythm, poses selection biases. Additionally, local practice variations, regional prehospital protocols and transport time, and intensive care unit extracorporeal membrane oxygenation management were unknown. Despite robust statistical adjustments and imputation, it is not clear if strict definitions of important variables were followed at all centers, such as “signs of life” and transient return of spontaneous circulation. These and other limitations influence the observed patient viability and applicability across diverse populations. The clinical application would have been strengthened by external validation, though this is partially mitigated through robust internal validation techniques. The study included patients undergoing ECPR from 2013 to 2018. While this seems relatively recent, ECPR technology and clinical protocols are advancing at light speed, not only influencing the performance and applicability of the START‐ECPR but further adding to the demand for external validation.

In conclusion, Dr Kawauchi and colleagues have delivered an insightful and clinically relevant manuscript. Derivation of the START‐ECPR demanded advanced, clinical insight and scientific rigor. While not ready for prime time, prospective external validation will confirm the score's practical applicability in guiding lifesaving decisions for patients with out‐of‐hospital cardiac arrest with nonshockable rhythms. I commend the authors for their significant efforts and thoughtful contributions to the field.

Disclosures

None.