Impella versus IABP in acute myocardial infarction complicated by cardiogenic shock

Abstract

Objective: We investigated the benefit of Impella, a modern percutaneous mechanical support (pMCS) device, versus former standard intra-aortic balloon pump (IABP) in acute myocardial infarction complicated by cardiogenic shock (AMICS).

Methods: This single-centre, retrospective study included patients with AMICS receiving pMCS with either Impella or IABP. Disease severity at baseline was assessed with the IABP-SHOCK II score. The primary outcome was all-cause mortality at 30 days. Secondary outcomes were parameters of shock severity at the early postimplantation phase. Adjusted Cox proportional hazards models identified independent predictors of the primary outcome.

Results: Of 116 included patients, 62 (53%) received Impella and 54 (47%) IABP. Despite similar baseline mortality risk (IABP-SHOCK II high-risk score of 18 % vs 20 %; p = 0.76), Impella significantly reduced the inotropic score (p < 0.001), lactate levels (p < 0.001) and SAPS II (p =0.02) and improved left ventricular ejection fraction (p = 0.01). All-cause mortality at 30 days was similar with Impella and IABP (52 % and 67 %, respectively; p = 0.13), but bleeding complications were more frequent in the Impella group (3 vs 4 units of transfused erythrocytes concentrates due to bleeding complications, p = 0.03). Previous cardiopulmonary resuscitation (HR 3.22, 95% CI 1.76 to 5.89; p < 0.01) and an estimated intermediate (HR 2.77, 95% CI 1.42 to 5.40; p < 0.01) and high (HR 4.32 95% CI 2.03 to 9.24; p = 0.01) IABP-SHOCK II score were independent predictors of all-cause mortality.

Conclusions: In patients with AMICS, haemodynamic support with the Impella device had no significant effect on 30-day mortality as compared with IABP. In these patients, large randomised trials are warranted to ascertain the effect of Impella on the outcome.

Keywords: IABP; cardiogenic shock; impella; mechanical support; myocardial infarction.

Figure 1

Changes in clinical parameters and use of catecholamines during hospitalisation (A) inotropic score, B) serum lactate levels and (C) SAPS II from baseline to the fourth day after device implantation, and (D) LVEF from baseline to discharge are depicted. measurements are presented as median and 25th–75th percentile. P values are from a generalised linear model considering the between and within difference among groups. The catecholamine dose was evaluated by the inotropic score (µ/kg/min.)=dopamine+dobutamine +100*epinephrine +100*norepinephrine +100*isoproterenol. IABP, intra-aortic balloon pump; LVEF, left ventricular ejection fraction; SAPS II, Simplified Acute Physiology Score II.

Figure 2

Kaplan-Meier estimates of all-cause mortality at 30 days. Depicted are the Kaplan-Meier estimates of all-cause mortality at 30 days. P-values from the log-rank test. events were analysed (A) in the whole study population, (B) after excluding deaths due to palliation by irreversible postanoxic brain damage, (C) in the low-intermediate and (D) high IABP-SHOCK II risk score subgroup. IABP-SHOCK II, Intra-aortic Balloon Pump in Cardiogenic Shock II.

Figure 3

Independent predictors of all-cause mortality at 30 days. (HRs are from COX regressions with 95% CIs). Events were analysed (A) in the whole study population and (B) in the subgroup of patientswith low-intermediate IABP-SHOCK II score. adjustment covariates including IABP-SHOCK II risk score and CPR. CPR, cardiopulmonary resuscitation; IABP-SHOCK II, Intra-aortic Balloon Pump in Cardiogenic Shock II.