Extracorporeal life support in fulminant myocarditis: on the side or in the centre?

The advent of extracorporeal life support (ECLS) represents a milestone in the treatment of appropriately selected patients with severe refractory cardiogenic shock [1]. Indeed, fulminant myocarditis (FM) can lead to such a state. This rare, but potentially fatal, entity often affects patients who are relatively young, and aggressive therapy is mandated [2]. In this edition of EJCTS, Tadokoro et al. [3] share their experience treating FM with different ECLS modalities. It is known that prompt initiation of peripheral ECLS is beneficial for patients struggling with refractory cardiac dysfunction and shock. Tadokoro et al. suggest that such promptness is also mandated in converting patients not faring well on peripheral ECLS. Their retrospective study of 70 patients demonstrates a statistically similar 5-year survival rate between those on peripheral and central ECLS. They also characterize the weaning course, which was more challenging in patients on central ECLS. Creatinine kinase-MB level over 180 IU/ml, protracted aortic valve closure and presence of rhythm disturbance were the 3 factors predictive of impaired recovery despite centrally implanted support. Understandably, these are proxies for extensive damage indicative of more serious pathology. The authors’ rigorous application of the Dallas criteria in identifying FM cases and the clarity of their decision-making process contribute to the strength of this analysis. Despite low case numbers due to the relatively rarity of FM, the authors offer precious insight on ECLS strategy. First, they demonstrate the feasibility of a dynamic and modular approach to ECLS, pushing the limits of convention. Then, they achieve comparable survival rates between the 2 groups, suggesting that surgical conversion to more invasive support results in clinical benefit, in spite of more severe FM. As a result, the authors deserve commendation for their well-defined and pertinent study of a challenging patient population. While they could have broadened their study by including patients requiring ECLS due to other causes, their focus on FM is appreciated given its contemporary relevance. Indeed, the SARS-CoV-2 virus has demonstrated its destructive potential on the heart. Cases of cardiac injury and clinically suspected myocarditis associated with the illness have been recognized, although the pathophysiology remains poorly defined [4]. Tadokoro et al. therefore offer a graduated strategy that could be relevant to the management of this serious occurrence. On the other hand, the authors’ focus on FM limits this study’s generalizability. Several processes (infarction, inflammation and infiltration to name a few) can cause profound cardiac damage requiring ECLS, and these entities are physiologically distinct. Subsequently, their respective recovery timelines differ. It is unclear whether outcomes of this study can be replicated in patient populations with acute cardiogenic shock caused by diseases other than FM. Even within FM, there exist important distinctions in patterns of myocardial damage and recovery [5]. For instance, human herpes virus 6 and parvovirus B19 trigger FM differently, and to different extents, as previously described in the literature [6]. Numerous avenues exist for further research. In subsequent investigations of ECLS therapy for refractory heart failure, it would be clinically useful to delineate patient-specific and disease-specific factors to identify those who would benefit from a central configuration instead of a peripheral one at the outset. This could potentially alleviate the need for, cost associated with, and complications of peripheral ECLS in certain situations. It is also unclear whether one particular central ECLS layout is to be favoured. The authors aptly demonstrate the absence of a risk differential between central support configurations, but do not comment on superiority of any one of them. As such, future work should be designed to refine the indications of each of these setups with the goal of optimizing recovery and modifying the disease course. In conclusion, Tadokoro et al. demonstrate promising results with the use of central ECLS modalities as the next step in treating patients with FM-related cardiogenic shock. In so doing, they provide additional management options for patients unresponsive to peripheral ECLS. Their study is an example of the creativity required to tackle challenging situations and improve outcomes in fatal conditions. Better understanding of each individual disease entity that will benefit from this expensive treatment modality will undoubtedly improve the cost-benefit and justification of ECLS application, which is easy to install but morally difficult to stop. This study is proof that our surgical specialty is alive and well, and much room exists for investigation and improvement.