Impella vs Veno-arterial extracorporeal membrane oxygenation in cardiogenic shock: a systematic review and meta-analysis of propensity score matched studies

Abstract

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Abiomed Singapore PTE. Ltd. Background/Introduction Cardiogenic shock is a life-threatening condition associated with multi-organ failure and death. Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is well-established in the management of cardiogenic shock; however, mortality rates have remained relatively consistent over the past two decades. Impella is a transluminal microaxial ventricular assist device that improves haemodynamics by unloading the left ventricle and represents an alternative to VA-ECMO. No randomised controlled trials exist to date comparing Impella versus VA-ECMO given difficulties in recruiting patients due to the acute nature of the condition. Whilst a plethora of non-randomised, comparative studies have been published, many are confounded by underlying differences in baseline disease characteristics. Propensity score matched / adjusted studies may mitigate confounding by accounting for differences in important covariates that impact outcomes. Purpose The objective of this study was to conduct a systematic review and meta-analysis of propensity score matched / adjusted studies to assess the clinical outcomes of Impella versus VA-ECMO in cardiogenic shock patients. Methods A systematic review was undertaken to identify all comparative studies of Impella and VA-ECMO in cardiogenic shock which performed propensity score matching / adjustment of outcomes to account for important covariates. The study limitations were assessed using the GRADE (Grading of Recommendations, Assessment, Development and Evaluations) approach. In-hospital/30-day survival and bleedings requiring transfusion were meta-analysed using the random effects method. Results Six propensity score matched / adjusted studies comparing Impella versus VA-ECMO in cardiogenic shock were included in the meta-analysis. A statistically significant difference in in-hospital/30-day mortality was detected between patients treated with Impella (39.6%) versus VA-ECMO (53.8%) (odds ratio [OR] 95% confidence interval [95% CI]: 0.57 [0.44, 0.74]; p<0.0001). Similarly, Impella (19.9%) was associated with statistically significantly fewer bleeding events requiring transfusion compared with VA-ECMO (28.8%) (OR=0.61 [0.46, 0.80]; p=0.0004). Conclusion(s) This systematic review identified no randomised controlled trials of Impella versus VA-ECMO. The meta-analysis of propensity matched observational trials, represents the highest level of evidence available to date, and suggests that Impella may be associated with increased survival rates and decreased bleeding. Randomised controlled trials are urgently needed to assess cardiac support modalities in cardiogenic shock.