IMPella versus IABP Reduces mortality in STEMI patients treated with primary PCI in Severe cardiogenic SHOCK - IMPRESS

Contribution To Literature:

The IMPRESS trial showed that outcomes following mechanical circulatory support are similar with both Impella CP and IABP among patients with STEMI and cardiogenic shock undergoing primary PCI.

Description:

The goal of the trial was to compare outcomes following Impella CP or intra-aortic balloon pump (IABP) in patients presenting with ST-segment elevation myocardial infarction (STEMI) and cardiogenic shock and undergoing primary percutaneous coronary intervention (PCI).

Study Design

Patients undergoing primary PCI for STEMI and cardiogenic shock were randomized in a 1:1 fashion to either Impella CP (n = 24) or IABP (n = 24).

  • Total number of enrollees: 48
  • Duration of follow-up: 30 days
  • Mean patient age: 58 years
  • Percentage female: 21%

Inclusion criteria:

  • Acute myocardial infarction with ST-segment elevation complicated by severe cardiogenic shock in the setting of immediate PCI
  • Mechanically ventilated before randomization

Exclusion criteria:

  • Severe aorto-iliac arterial disease impeding placement of either device
  • Known severe cardiac aortic valvular disease
  • Serious known concomitant disease with a life expectancy of <1 year
  • Known participation in this study or any other trial within the previous 30 days or coronary artery bypass grafting within the preceding week

Other salient features/characteristics:

  • Diabetes: 11%
  • Infarct-related artery: left anterior descending 65%
  • Multivessel disease: 7%
  • Cardiac arrest before randomization, 91%; first rhythm ventricular tachycardia/ventricular fibrillation, 88%
  • Therapeutic hypothermia: 75%
  • Baseline ejection fraction >40%: 27%
  • Median duration of support: 48 hours

Principal Findings:

The primary outcome, all-cause mortality for Impella CP vs. IABP, was 46% vs. 50%, p = 0.92.

Secondary outcomes (for Impella CP vs. IABP):

  • All-cause mortality at 6 months: 50% vs. 50%, p = 0.92
  • Stroke at 30 days: 4% vs. 4%, p > 0.05
  • Major vascular complication: 4% vs. 0%
  • Major bleeding: 33% vs. 8%
  • Hemolysis requiring device removal: 8% vs. 0%

Interpretation:

The results of this small trial indicate that outcomes following mechanical circulatory support (MCS) were similar with both Impella CP and IABP among patients with STEMI and cardiogenic shock undergoing primary PCI. This is despite the fact that the Impella CP device can provide hemodynamic support of approximately 3-3.5 L/min compared with an IABP that typically provides 0.8-1 L/min of mechanical support. Sheath sizes are different: 14 Fr vs. 7.5 Fr, thus not surprisingly, vascular and bleeding complications were higher with the Impella CP device. The trial was significantly underpowered.

One must note that this was a very critically ill population. Nearly all had experienced cardiac arrest, with a median lactate level of nearly 8 mmol/L and a pH of 7.15. The major cause of death was anoxic brain injury, suggesting that MCS may be of limited utility in this patient population overall.

References:

Ouweneel DM, Eriksen E, Sjauw KD, et al. Impella CP Versus Intra-Aortic Balloon Pump in Acute Myocardial Infarction Complicated by Cardiogenic Shock: The IMPRESS trial. J Am Coll Cardiol 2016;Oct 31:[Epub ahead of print].

Editorial Comment: Zeymer U, Thiele H. Mechanical Support for Cardiogenic Shock: Lost in Translation? J Am Coll Cardiol 2016;Oct 31:[Epub ahead of print].

Research Letter: Ouweneel DM, Eriksen E, Seyfarth M, Henriques JP. Impella Versus Intra-Aortic Balloon Pump For Treatment Of Cardiogenic Shock: A Meta-Analysis of Randomized Controlled Trials. J Am Coll Cardiol 2016;Oct 31:[Epub ahead of print].

Presented by Dr. Jose P.S. Henriques at the Transcatheter Cardiovascular Therapeutics meeting (TCT 2016), Washington, DC, October 31, 2016.

Clinical Topics: Acute Coronary Syndromes, Arrhythmias and Clinical EP, Cardiac Surgery, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Aortic Surgery, Cardiac Surgery and Arrhythmias, Cardiac Surgery and Heart Failure, Acute Heart Failure, Mechanical Circulatory Support , Interventions and ACS

Keywords: Acute Coronary Syndrome, Arrhythmias, Cardiac, Brain Injuries, Critical Illness, Heart Arrest, Hemolysis, Hemodynamics, Hemorrhage, Hypothermia, Induced, Intra-Aortic Balloon Pumping, Myocardial Infarction, Percutaneous Coronary Intervention, Shock, Cardiogenic, Stroke, Transcatheter Cardiovascular Therapeutics


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