Early and long-term outcomes of extracorporeal membrane oxygenation support in refractory cardiogenic shock for non-surgical patients: nine years experience at our Institute
Authors: St-Pierre G , Laflamme L , Charbonneau E , Sia Y.T 
Published: November 2020

Abstract

Purpose
Venoarterial extracorporeal membrane oxygenation (VA-ECMO) support is ultimately applied in refractory cardiogenic shock and is associated with high in-hospital mortality. We sought to describe the characteristics and analyze early and long-term outcomes of patients with refractory cardiogenic shock at our institution as well as our approach to patient selection.

Methods
This single-center retrospective study used the ECMO database from the cardiac surgery department to identify all patients with refractory cardiogenic shock at our Institute. VA-ECMO for patients with postcardiotomy shock, on-going cardiopulmonary resuscitation and venovenous ECMO were excluded. Primary endpoint was in-hospital mortality after VA-ECMO. Secondary outcomes were early complications on VA-ECMO and long-term survival after hospital discharge. Refractory cardiogenic shock was defined by either hypotension or end-organ failure despite adequate inotropic support.

Results
All patients with refractory cardiogenic shock were admitted to our cardiological ICU and our Heart team was systematically consulted. This team was mainly composed of transplant and LVAD cardiologists and cardiac surgeons specialized in ECMO. After case discussion, the decision for VA-ECMO implantation as a bridge therapy was made if the patient was deemed candidate to advance heart failure treatment. VA-ECMO was rapidly implanted by cardiac surgeons at bedside or in operating room with a median time from decision to implantation of 150 minutes (IQR: 100–233).
Fifty-nine patients underwent VA-ECMO for refractory cardiogenic shock between 2010–2019. Patients were 52.1±14.5 years old, 75% were male and more than 90% were not known for any prior cardiac history. The indication for VA-ECMO support was acute myocardial infarction in 34 patients (58%) with reduced LVEF, mitral regurgitation, arrhythmia storm or ventricular septal defect. Myocarditis occurred in 19% of patients. The median LVEF was 13% (IQR: 10–31). Peripheral cannulation was most frequently implanted (92%). During VA-ECMO support, 43 patients survived and 16 patients died. Figure 1 shows weaning strategies for patients who survived VA-ECMO support. Of these, 37 patients survived up to discharge (86%). After a median follow-up of 2.9 years (IQR: 1.8–4.8), 92% were alive. The median time on VA-ECMO support was 4.9 days (IQR 3.5–7.6). Complications were bleeding needing reoperation (41%), pneumonia (41%), renal failure requiring dialysis (39%) and limb ischemia (17%).

Conclusion
In our experience, venoarterial ECMO is a feasible and acceptable alternative to support patients with refractory cardiogenic shock despite inotropic agents. Interestingly, the survival rate was particularly high as compared to the literature. This could be explained by patient selection and early VA-ECMO implantation.
Evolution of patients after ECMO

Funding Acknowledgement
Type of funding source: None