Mortality in patients with cardiogenic shock treated with the Impella CP microaxial pump for isolated left ventricular failure

Cardiogenic shock is still associated with high mortality rates of around 50%. Intra-aortic counterpulsation had been frequently used in cardiogenic shock, but was previously found to provide no mortality benefit. We investigated the effect of an interdisciplinary and multiprofessional routine strategy of early invasive haemodynamic support in combination with complete revascularization in patients with cardiogenic shock before admission to our intensive care unit.

We analysed all cardiogenic shock patients (mean age 62±13 years) presenting at our institution between 2013 and mid 2016, who received an Impella CP microaxial pump for isolated left ventricle support (n=61). Sixty-one per cent (n=37) had been resuscitated before Impella insertion. Overall mortality was 48% (n=29/61) at 30 days. Thirty-day mortality was higher in resuscitated patients (resuscitated: 65% (n=24/37); non-resuscitated: 21% (n=5/24)). When applying the inclusion/exclusion criteria of the SHOCK-II trial, eligible patients (n=25) had a markedly lower mortality (24% (n=6/25) at 30 days) compared with the published trial (~40% in both arms). The observed mortality of SHOCK-II-like patients in the registry was also lower compared with their predicted mortality using IABP-Shock II score (49%) and CardShock score (36%).

The results of this registry suggest that using a standardized protocol including early active haemodynamic support with Impella CP in cardiogenic shock in patients with isolated left ventricle failure may be associated with improved outcomes and lower than previously reported or predicted mortality rates. Pre-implantation cardiac arrest critically influences observed mortality. The results support the case for a randomized trial.