Editorial

The use of percutaneous temporary mechanical circulatory support (tMCS) devices has changed dramatically over the last decade. While the use of intra-aortic balloon pump (IABP) has decreased, the use of microaxial flow pumps (mAFP) and veno-arterial extracorporeal membrane oxygenation (V-A ECMO) has increased. Cardiogenic shock (CS) is a complex, heterogenous, and haemodynamically challenging condition. Research in this area is notoriously difficult to conduct and there exists no robust evidence supporting a benefit in mortality. This is generally true for all pump types apart from V-A ECMO, which has demonstrated benefit in refractory cardiac arrest in one small trial. As a result, there is no agreement for tMCS use across publications, and guidelines are not specific regarding patient and device selection.

This complexity of CS is compounded by a lack of pulse pressure and reversal of aortic flow when tMCS are employed in this setting. Parsing the interplay between human physiology and individual devices is challenging and fascinating; tMCS may be immediately lifesaving in some patients, providing stabilization of haemodynamics and recovery of the heart function, while in others the condition continues to deteriorate despite adequate device performance. Currently, the combination of mAFP and V-A ECMO, termed ECMELLA, is used to overcome the theoretical disadvantages of afterload increase from V-A ECMO. However, there are no clear venting criteria in place and randomized controlled trial (RCT)-driven data are also lacking.

In addition to a dearth of consensus on the benefit of mAFP, V-A ECMO, and ECMELLA, there is a gap in data-driven guidance for device management, particularly post-implantation in the intensive care unit. Outcomes of CS and tMCS complications are often played out in real-time. Therefore, new interdisciplinary competence is necessary to master all aspects of patient care. The indications for selection of specific tMCS, escalation, and weaning strategies should be evaluated in RCTs, although these studies are unlikely to address all facets of treatment and daily management. Moreover, even if event-driven upcoming RCTs are neutral, these devices will likely still be used in selected patients.

As such, the goal of this supplement is to provide the reader with expert knowledge on the clinical approach to the most important phases of tMCS patient management. This supplement is a contemporary, comprehensive overview of the best practices as considered by this group of experienced users. This overview has been developed over recent years based on existing retrospective and prospective registries, as well as personal and global expertise. The community has fully endorsed the value of the Society for Cardiovascular Angiography and Interventions (SCAI) staging and its role in defining the severity of patient status; thus, this nomenclature is the ‘red line’ of this supplement, though limitations and knowledge gaps will be also detailed.

It is necessary to first discuss the essentials of patient identification and selection, as current evidence suggests that some patients may receive more benefit from tMCS support than others. Within this section is a discussion on SCAI classification and the impact of temporary changes on this classification due to the dynamic nature of CS. Sex-related differences in CS and the different CS phenotypes will also be covered, with a focus on CS caused by acute myocardial infarction (AMI-CS). Once a patient has been selected for tMCS support, clinicians must navigate the decision on device selection and a treatment strategy.

To that end, the basic principles of CS treatment will be reviewed, including a description of tMCS and a proposed algorithm of device selection based on device characteristics. Best practices on implantation techniques and periprocedural patient management are also proposed. Timing of tMCS initiation may be crucial to successful outcomes of tMCS therapy. Therefore, a discussion is presented on determining the optimal timing for mAFP, V-A ECMO, or ECMELLA, and aspects of revascularization strategies in AMI-CS. Additionally, the issue of shock networks and transportation of critically ill CS patients is considered, with attention given to the pitfalls inherent to the current systems. The focus then shifts to patient management and monitoring, with suggestions for best practices for tMCS in intensive care medicine. This includes noting the options for escalation with different mAFPs, V-A ECMO cannulation strategies, and other right heart-supporting devices. ECMELLA is discussed in depth, including escalation and de-escalation strategies and a proposed weaning protocol. Finally, we look into the future, interpreting the outcomes of the latest CS trials and their potential impact on daily clinical practice, and discuss future trials highlighting the hopes and difficulties in performing RCTs in the setting of CS (Figure 1).

Figure 1.

Successful MCS management of CS patients is a multifactorial process. From appropriate patient and device selection through best practices for timing, monitoring, escalation, and weaning, clinicians must take many factors into consideration when treating CS patients with MCS. This supplement is designed to guide users through the current state of the field and provide a glimpse into the future of MCS for CS. MCS, mechanical circulatory support; CS, cardiogenic shock; SCAI, Society for Cardiovascular Angiography & Interventions; pVAD, percutaneous ventricular assist device; mAFP, microaxial flow pumps; V-A ECMO, veno-arterial extracorporeal membrane oxygenation; ECMELLA, combined use of Impella and V-A ECMO; AMI-CS, acute myocardial infarction with cardiogenic shock.

This multidisciplinary compilation from experts throughout Europe provides a powerful opportunity to highlight the ongoing need for overarching guidelines on patient care decisions. Indeed, the difficulties that many trials are facing in CS underscore the lack of definite definitions and timely identification of patients. This results in the provision of care in higher SCAI stages, when the need for cardiopulmonary resuscitation plays a major prognostic role. Future considerations should focus on the proficiency required to manage complications and special scenarios during tMCS support, as concepts routinely applied to ‘typical’ patients are not necessarily optimal in the setting of CS due to applicability (e.g. endomyocardial biopsy) or reproducibility (e.g. antibiotic dosing). Collectively, we hope these articles will be of particular interest to the readers of the European Heart Journal Supplements.

Funding

This work has been supported by Abiomed Europe GmbH to cover publication costs as well as professional language editing of each manuscript. No individual fees were paid to the authors in the generation of this publication. This paper was published as part of a supplement financially supported by Abiomed GmbH.

Data availability

No new data were generated or analysed in support of this research.