43 The role of mechanically-supported emergency percutaneous coronary intervention in cardiogenic shock

Abstract

Background Historically, the intra-aortic balloon pump (IABP) has been the primary means of providing rapid mechanical circulatory support (MCS) in patients undergoing emergency revascularisation for acute myocardial infarction complicated by cardiogenic shock (AMI-CS). Despite the availability of alternative devices such as the percutaneous Impella 2.5/CP® which have displayed superior haemodynamic support in animal models, evidence in support of their use in humans is limited and international guidelines do not currently recommend their use. This review aims to examine the existing literature in order to compare survival outcomes in AMI-CS patients undergoing emergent revascularisation supported by percutaneous MCS devices; IABP and Impella 2.5/CP, to discuss the implications of the findings on clinical practice. Method A review of the literature was conducted through the application of search terms ‘Intra-aortic balloon pump’, ‘Impella’, ‘Cardiogenic shock’ and ‘Mortality’ to four databases: Ovid Medline, Ovid Embase, Cochrane and Web of Science. This resulted in 1,823 studies which were then screened based on title and abstract before full text analysis to identify studies that met pre-defined inclusion and exclusion criteria. Results 12 studies met the eligibility criteria: 2 randomised controlled trials (RCTs) and 10 observational studies. In total 28,104 patients were included. 10 studies compared outcomes in patients treated with IABP compared to control. Only 2 studies directly compared outcomes in patients supported by the IABP vs Impella®. The results were inconsistent. 10/12 studies found no difference in mortality between intervention and control arms. Notably, one study claimed reduced mortality with IABP vs control, and one study concluded that Impella® improved survival rates when compared to IABP. The average 30-day all-cause mortality in patients treated with IABP was 42.5% vs 37% in patients treated with Impella® which is consistent with historical studies. Conclusion AMI-CS represents an important cohort of patients in whom conducting RCTs is difficult. As a result, the literature is limited. Analysis of the studies available suggests that there is insufficient evidence to support superior survival in those supported by IABP or Impella® when compared to control. Despite noting positive findings in terms of demonstratable haemodynamic support associated with the Impella® in porcine models these benefits have not been observed in human studies. This literature review failed to establish superior survival associated with the use of IABP or the Impella®, however limitations of the studies have been discussed to outline suggestions for future research. Conflict of Interest None