Mechanical Circulatory Support with the Impella® LP5.0 Pump and an Intra-Aortic Balloon Pump for Cardiogenic Shock in Acute Myocardial Infarction: The IMPELLA-STIC Randomized Study
Background
Percutaneous assist devices may be used as a bridge to recovery in patients with acute myocardial infarction complicated by cardiogenic shock (CS-AMI).
Aim
To test the hypothesis that the Impella® LP5.0 pump (Abiomed Europe GmbH, Aachen, Germany) provides haemodynamic benefits and improves left ventricular ejection fraction (LVEF) in patients with CS-AMI already managed with an intra-aortic balloon pump (IABP).
Methods
This was a prospective randomized study. The primary endpoint was change in cardiac power index (CPI) from baseline to 12 hours after implantation, measured with a Swan-Ganz catheter. Secondary endpoints included LVEF at 30 days.
Results
Fifteen patients with CS-AMI were randomized; 12 were available for primary endpoint analysis (IABP group, n = 6; Impella LP5.0 + IABP group, n = 6). Baseline characteristics were similar in both groups. Change in CPI after 12 hours was not significantly different between the two groups (IABP group: ΔCPI = 0.08 ± 0.08 W/m2; Impella LP5.0 + IABP group: ΔCPI = –0.02 ± 0.25 W/m2; P = 0.4). There was no significant change from baseline CPI in either group over 96 hours, and no difference in CPI between groups at each timepoint. In the Impella LP5.0 + IABP group, the part of the CPI provided by the native heart decreased from 0.37 ± 0.10 to 0.10 ± 0.20 (P = 0.01). LVEF was similar at baseline (29.7% ± 8.4% and 29.3% ± 6.7%) and 1 month (40.6% ± 12.5% and 38.6% ± 14.4%) in the IABP and Impella LP5.0 + IABP groups, respectively. Adverse events, especially major bleeding, were common, and occurred mainly in the Impella LP5.0 + IABP group.
Conclusions
In patients with CS-AMI stabilized by initial treatment with inotropes and an IABP, the Impella LP5.0 did not provide additional haemodynamic support or improvement in LVEF at 1 month; its use in this setting might be futile and possibly harmful.
