Schaeffer et al. present a retrospective single-centre study analysing 23 years of experience at a German referral centre with the use of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) as circulatory support following congenital heart surgery. The primary objective was to identify factors associated both with the need for ECMO support and with in-hospital survival among patients requiring this therapy, with particular attention to the impact of support duration on clinical outcomes.

During the study period, 9892 congenital heart surgery procedures were evaluated, approximately 1.8% of which required VA-ECMO because of refractory cardiopulmonary failure. The authors analysed the clinical, surgical, and postoperative characteristics of this cohort, including variables related to the underlying congenital heart defect, surgical complexity, age, cardiopulmonary bypass (CPB) times, complication rates, and mortality despite mechanical circulatory support.

The results showed that, among patients younger than 2 years, the need for ECMO was significantly more frequent in those with single-ventricle physiology undergoing highly complex procedures such as the Norwood procedure, in patients undergoing repair of coronary artery malformations, and in those experiencing perioperative cardiopulmonary resuscitation or prolonged CPB times. Among patients older than 12 years, prolonged CPB times and perioperative cardiopulmonary resuscitation were particularly relevant. In-hospital survival was approximately 45%, a figure comparable to that reported in major international registries and one that illustrates both the value of ECMO as a rescue therapy and the extreme severity of illness among patients in whom it is required.

Regarding mortality, multivariable analysis identified acute kidney injury requiring renal replacement therapy (RRT) as one of the main independent predictors of death among patients younger than 2 years. In addition, the authors observed that ECMO support extending beyond 6 days was associated with an increasing risk of adverse outcomes, suggesting that the clinical course during the first week of support represents a particularly important period for reassessing the likelihood of recovery.

The authors conclude that ECMO remains an essential tool in the management of refractory circulatory failure after congenital heart surgery and emphasize the importance of early identification of factors associated with poor prognosis, together with continuous reassessment throughout mechanical support. In this regard, the study provides useful information for clinical decision-making, particularly concerning the temporal evolution of patients and the need to reassess dynamically whether ongoing mechanical support remains appropriate.

COMMENTARY:

Extracorporeal membrane oxygenation (ECMO) is currently the main form of circulatory support for patients with refractory cardiopulmonary failure following congenital heart surgery. Technological advances in ECMO systems, the development of specialized multidisciplinary teams, and the progressive standardization of ECMO programmes have broadened its indications and improved procedural safety. Nevertheless, these advances have not resolved the fundamental dilemma that continues to accompany this therapy. The decision to initiate ECMO is usually relatively well defined; far more difficult is determining which patients will derive meaningful benefit from support, how their subsequent clinical course should be interpreted, and, particularly, when ECMO ceases to represent a bridge to recovery and instead becomes a means of prolonging an irreversible pathophysiological process.

Rather than providing survival figures substantially different from those already reported, the main contribution of this study lies in shifting attention toward a much less extensively investigated question: what happens after ECMO has been initiated. Traditionally, the literature has focused primarily on defining indications for support, describing complications, or comparing outcomes between centres. Clinical practice, however, shows that the most difficult decisions are rarely made at the time of implantation. The real challenge begins over the following days, when the multidisciplinary team must determine whether there remains a reasonable likelihood of myocardial recovery, whether residual lesions amenable to correction are present, whether the patient should be considered for durable ventricular assist device support, or whether progressive multiorgan failure should instead prompt reconsideration of the therapeutic goals.

This concept has implications that extend beyond the study itself. Too often, continuation of support reflects the absence of an immediate alternative rather than the presence of a clearly defined therapeutic strategy. Each additional day on ECMO should prompt renewed consideration of several fundamental questions: does a reversible cause remain? Is there objective evidence of cardiac recovery? Is the original goal of support still achievable? When these questions can no longer be answered affirmatively, prolonging ECMO is unlikely to alter the patient’s prognosis. From this perspective, the study by Schaeffer et al. does not propose a time limit for support but rather provides a framework for making its continuation more rational and structured.

Within this context, the significant increase in mortality beyond the sixth day of support is particularly relevant. It would be inappropriate to interpret this finding as a chronological threshold beyond which withdrawal of support should routinely be considered. Myocardial recovery is an extraordinarily variable process influenced by numerous anatomical and pathophysiological factors. The principal value of this finding is that it transforms a widely shared clinical perception into an objective element that can be incorporated into decision-making, rather than defining a fixed time limit for ECMO. Day 6 should therefore be regarded as a clinical inflection point prompting structured reassessment rather than as an expiration date for mechanical support. ECMO should not be viewed as a single decision made at the time of implantation, but rather as a dynamic strategy whose continued indication must be justified daily according to clearly defined therapeutic objectives.

The identification of acute kidney injury requiring RRT as a major independent predictor of mortality is also particularly noteworthy. This finding may be better interpreted as a marker of overall pathophysiological severity rather than simply as a complication attributable to ECMO and is consistent with previous reports. It also raises an important question that the study does not directly answer but that inevitably emerges from its findings: are we initiating ECMO too late? It is possible that some of the high mortality observed in these series reflects not so much the limitations of extracorporeal support itself as the degree of organ dysfunction already established by the time ECMO is finally initiated. If this hypothesis is correct, future progress may depend not only on further technological refinement of ECMO systems but also on developing tools capable of identifying patients who could benefit from earlier support, before irreversible multiorgan failure develops.

Nevertheless, these findings should be interpreted in light of several methodological limitations that, although considered in the analysis, remain potential sources of bias. Paradoxically, the greatest strength of the study is also one of its main limitations. Analysing 23 years of accumulated experience provides an exceptional cohort for a relatively uncommon clinical scenario. However, it also means that markedly different surgical strategies, ECMO programmes, intensive care protocols, and criteria for initiating support coexist within the same series. It was not only the devices that changed; the overall concept of mechanical circulatory support also evolved. Over this period, surgical techniques, extracorporeal circuits, anticoagulation strategies, perioperative management, and even candidate selection underwent substantial changes. Consequently, it is difficult to regard the cohort as entirely homogeneous. An analysis stratified by treatment era could have helped determine whether the prognostic impact of variables such as duration of support remains consistent in contemporary practice or partly reflects historical changes in treatment and the institutional learning curve.

This temporal heterogeneity is compounded by the extraordinary anatomical diversity of congenital heart disease. Although multivariable analysis attempts to account for these differences, it seems unlikely that prognostic factors have the same significance in a neonate undergoing a Norwood procedure as in an older patient with biventricular physiology. Similarly, the study continues to use in-hospital survival as its principal outcome. In a paediatric population with potentially many decades of life ahead, however, survival to discharge represents only the first stage of recovery. Neurological preservation, neurodevelopment, quality of life, and the need for subsequent interventions are increasingly relevant outcomes and should be systematically incorporated into future studies.

The study also raises a conceptual and ethical issue that receives relatively limited explicit consideration. ECMO is a supportive therapy, not a curative treatment. Its usefulness depends on the existence of a clinically achievable goal: myocardial recovery, transition to durable ventricular assist device support, or heart transplantation. When none of these options is feasible, continuing support no longer represents a bridge and may instead become a potentially futile intervention. Identifying that point is probably one of the most difficult decisions in contemporary cardiovascular surgery. No algorithm can resolve it, nor can any biomarker replace clinical judgement. It requires continuous reassessment, multidisciplinary evaluation, and appropriate integration of the patient’s physiological trajectory, realistic therapeutic possibilities, and overall goals of care.

In summary, Schaeffer and colleagues present a robust and clinically relevant study that is unlikely, by itself, to change current indications for ECMO. Its main contribution is not to redefine the indications for mechanical support, but rather to remind us that the success of this therapy depends less on the moment at which it is initiated than on the quality of the clinical judgement applied when reassessing whether it should be continued. The study may not tell us exactly when ECMO should be discontinued, because no study can provide a universally applicable answer. It does, however, reinforce a fundamental principle that is sometimes overlooked: initiating ECMO is a technical act; deciding, day after day, whether continuing it still makes sense is an exercise in clinical judgement. At least for now, no technological innovation has been able to replace that judgement.

REFERENCE.

Schaeffer T, Hayat S, Matsubara M, Palm J, Lemmen T, Heinisch PP, et al. Early outcomes of extracorporeal membrane oxygenation in congenital heart surgery. Eur J Cardiothorac Surg. 2026;68(6):ezag123. doi:10.1093/ejcts/ezag123.