AMI Cardiogenic Shock
Early Utilization of Mechanical Circulatory Support in Acute Myocardial Infarction Complicated by Cardiogenic Shock
The National Cardiogenic Shock Initiative
Mir B. Basir, DO et al.
Key Topics and Take Aways
- Early use of mechanical circulatory support (MCS; Impella CP in 92% of cases) in patients with acute myocardial infarction complicated by cardiogenic shock (AMI-CS), resulted in improvements to early hemodynamics and perfusion.
- Results from the NCSI study demonstrated 99% procedural survival, 71% survival to discharge, 68% survival to 30 days, and 53% survival to one year.
- Best practices emerging from the National Cardiogenic Shock Initiative (NCSI) study include MCS before percutaneous coronary intervention (pre-PCI), door-to-support <90 minutes, establishing TIMI 3 flow, using a right heart catheter (RHC), weaning of inotropes, and maintaining cardiac power output (CPO) > 0.6W, all with the aim of achieving survival to hospital discharge of ≥ 80%.
Early use of MCS as part of a shock protocol or team-based system was linked to high survival when compared with prior clinical trials with similar inclusion criteria and shock stages.
The NCSI (National Cardiogenic Shock Initiative) study is a single-arm, multicenter study with the primary outcome of assessing the feasibility of using a shock protocol and assessing in-hospital survival in patients with acute myocardial infarction complicated by cardiogenic shock (AMI-CS). Secondary outcomes included assessing the effect of mechanical circulatory support (MCS) on early hemodynamics and perfusion and assessing survival at 30 days and one year. The study included 406 patients treated between 2016 and 2020.
The investigators undertook this study to provide clinicians with a more uniform mechanism for the use of MCS and to help fill the void of inexperience and unfamiliarity regarding MCS. The authors of the study write, “Previous work from the catheter-based ventricular assist devices (cVAD) registry demonstrated that early use of an Impella® heart pump, particularly pre-PCI and before escalating the number of vasoactive agents, was associated with improved survival. We therefore created a shock protocol that emphasized the early use of MCS with Impella, guided by invasive hemodynamics, and assessed the feasibility of using such an approach and its effect on early hemodynamics, perfusion, and in-hospital survival.”
In this study, MCS, being Impella CP® in 92%, was inserted pre-PCI in 70% of patients and a right heart catheter (RHC) was used in 91% of the index procedures. Initial hemodynamics demonstrated that patients had decreased cardiac power output (CPO) of 0.67 W, and at 24 hours CPO had increased to 1.0 W. The median door to support time was 78 minutes, while the median door-to-balloon time was 81 minutes in patients with ST-elevation myocardial infarction (STEMI). Ninety percent of patients presented with less than thrombolysis in myocardial infarction (TIMI) 3 flow at baseline, with 91% achieving TIMI 3 flow at the end of the procedure.
This study demonstrated 99% procedural survival, 71% survival to discharge, 68% survival to 30 days, and 53% survival to one year. When patients were retrospectively classified and stratified by Society for Cardiovascular Angiography and Intervention (SCAI) shock stages, patients with SCAI shock stage C or D achieved 99% procedural survival, 79% survival to discharge, 77% survival to 30 days, and 62% survival to one year. Patients with SCAI shock stage E had survival rates of 98%, 54%, 49% and 31%, respectively.
Best practices for AMI-CS emerging from the study include:
- MCS Pre-PCI
- Door-to-support <90 minutes
- Establish TIMI 3 flow
- RHC utilization
- Wean Inotropes
- Maintain CPO > 0.6W
- Aim to achieve survival to hospital discharge of 80% or higher
The authors of this paper conclude that, “Early use of MCS in AMI-CS is feasible across varying health care settings and resulted in improvements to early hemodynamics and perfusion. Survival rates to hospital discharge were high. Given the encouraging results from our analysis, RCTs are warranted to assess the early use of MCS using a standardized, multidisciplinary approach.”
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