Percutaneous Mechanical Circulatory Support vs. IABP in Cardiogenic Shock

Study Questions:

What is the impact of a percutaneous mechanical circulatory support (pMCS) device (Impella) on 30-day mortality when compared with an intra-aortic balloon pump (IABP) in patients with severe shock complicating acute myocardial infarction (AMI)?


IMPRESS in Severe Shock was a randomized, prospective, open-label, multicenter trial, in which 48 patients with severe cardiogenic shock complicating AMI were assigned to pMCS (n = 24) or IABP (n = 24). Severe cardiogenic shock was defined as systolic blood pressure <90 mm Hg or the need for inotropic or vasoactive medication and the requirement for mechanical ventilation. The primary endpoint was 30-day all-cause mortality. All data were analyzed according to the intention-to-treat principle. In addition, a per-protocol analysis of the primary endpoint was performed. Cumulative mortality throughout the first 6 months following randomization was characterized with the use of Kaplan-Meier plots, with the log-rank test used for the comparison between the two groups.


At 30 days, mortality in patients treated with either IABP or pMCS was similar (50% and 46%, respectively; hazard ratio with pMCS, 0.96; 95% confidence interval, 0.42-2.18; p = 0.92). At 6 months, mortality rates for both pMCS and IABP were 50% (hazard ratio, 1.04; 95% confidence interval, 0.47-2.32; p = 0.923).


The authors concluded that routine treatment with pMCS was not associated with reduced 30-day mortality compared with IABP in patients with severe shock complicating AMI.


This randomized trial comparing Impella with the IABP in mechanically ventilated patients with cardiogenic shock complicating AMI reports that pMCS support with Impella was not associated with lower 30-day or 6-month mortality when compared with IABP support. While further studies are indicated to clarify the clinical characteristics of patients with cardiogenic shock who benefit from one mode of mechanical circulatory support more than another, routine use of Impella is not indicated in these patients.

Clinical Topics: Acute Coronary Syndromes, Cardiac Surgery, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Aortic Surgery, Cardiac Surgery and Heart Failure, Acute Heart Failure, Mechanical Circulatory Support, Interventions and ACS

Keywords: Acute Coronary Syndrome, Blood Pressure, Heart-Assist Devices, Heart Failure, Intra-Aortic Balloon Pumping, Myocardial Infarction, Percutaneous Coronary Intervention, Respiration, Artificial, Shock, Shock, Cardiogenic

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