Author + information
- Juan J. Russo, MD,
- Pietro Di Santo, MD,
- Ajay J. Kirtane, MD, SM and
- Benjamin Hibbert, MD, PhD∗ ()
- ↵∗Ottawa Heart Institute, 40 Ruskin Street, Ottawa, Ontario K1Y 4W7, Canada
We thank Dr. Li and colleagues and Dr. Meuwese and colleagues for their comments and additional analyses provided in their letters. Although the findings of our meta-analysis help inform the decision to unload the left ventricle in patients treated with venoarterial extracorporeal membrane oxygenation (VA-ECMO) for cardiogenic shock, we caution that the underlying data supporting an association between left ventricular unloading and reduced mortality remains observational (1). To this end, the analysis by Meuwese and colleagues confirms the overall meta-analysis in the subset of studies that provided adjusted risk ratios. Secondarily, we agree with Li and colleagues that the specific left ventricular unloading strategy (e.g., timing or modality) may have an important modulating effect on the association between left ventricular unloading and mortality warranting further investigation. In our analysis, we found no heterogeneity in the relationship between left ventricular unloading and all-cause mortality when an intra-aortic balloon pump or percutaneous left ventricular assist device was used. We did not include studies examining cannula-based vents in this specific comparison as statistical analyses were limited by the small sample size of this subset (n = 94). Although there are many reports of the use of cannulas for left ventricular unloading during VA-ECMO, our pre-specified protocol mandated reporting of mortality with left ventricular unloading and in a control group, leading to the exclusion of uncontrolled surgical case series. In some settings, the current standard of care for the management of cardiogenic shock with mechanical circulatory support has sped ahead of the available evidence. As a result, practitioners managing patients with cardiogenic shock may be resorting to observational data or expert opinion alone as a foundation for clinical decisions. Buoyed by a common interest to improve clinical outcomes in cardiogenic shock, randomized comparisons to establish the treatment effect of VA-ECMO and left ventricular unloading in patients with cardiogenic shock are needed and are feasible in the current era.
Please note: The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- 2019 American College of Cardiology Foundation