Elsevier

American Heart Journal

Volume 238, August 2021, Pages 66-74
American Heart Journal

Clinical investigations
Clinical features and outcomes in patients with cardiogenic shock complicating acute myocardial infarction: early vs recent experience with impella

https://doi.org/10.1016/j.ahj.2021.04.002Get rights and content

Objectives

To compare clinical features and outcomes in patients with acute myocardial infarction complicated by cardiogenic shock (AMICS) treated in the early experience with Impella percutaneous ventricular assist device and patients treated recently.

Background

Since pre-market approval (PMA) of Impella device as treatment for AMICS, use of the device has grown considerably.

Methods

We retrospectively analyzed 649 AMICS patients treated with perioperative Impella, with 291 patients treated from 2008 to 2014 comprising the early experience cohort and 358 patients treated from 2017 to 2019 comprising the recent experience cohort. The primary end point was risk adjusted in-hospital mortality.

Results

Mean age and gender distribution of patients was similar in the two cohorts. The recent cohort had more invasive hemodynamic monitoring (64% vs 46%; P < .001) and less use of an intra-aortic balloon pump prior to Impella (15% vs 41%; P < .001). Recently treated patients were significantly more likely to receive Impella support prior to PCI (58% vs 44%; P = .005). In-hospital mortality was lower in the recent cohort (48% vs 56%; P = .043). This difference was however no longer significant after risk adjustment (adjusted OR 0.89, 95% CI 0.59-1.34, P = .59). Rates of acute kidney injury, major bleeding, and vascular complications requiring surgery were also significantly lower in the recent cohort.

Conclusions

Use of Impella for AMICS during recent years is associated with lower unadjusted in-hospital mortality, which may reflect better patient selection, earlier device implantation, and improved management algorithms. In-depth understanding of these factors may inform the development of future treatment protocols.

Introduction

Despite significant advances in early revascularization and pharmacological strategies, cardiogenic shock remains the most common cause of death in patients with acute myocardial infarction.1,2 The overall incidence of cardiogenic shock in acute myocardial infarction (AMICS) is reported between 7%-10% and has remained steady over recent times.3,4 The in-hospital mortality continues to remain high, ranging between 27% and 51%.5,6 Coronary reperfusion achieved through percutaneous or surgical revascularization remains pivotal to survival of these patients;7,8 adjunct pharmacological strategies or the use of intra-aortic balloon counterpulsation (IABP) have not been shown to positively affect outcomes.7,9,10 Alternatively, percutaneous ventricular assist devices (pVAD) are increasingly used as part of contemporary management of selective AMICS patients, with a recent study finding that early placement of Impella CP (Abiomed, Danvers, MA), a commonly used pVAD, was associated with improved 30-day mortality compared to a control group of IABP-treated patients in an AMICS patient population.11

In the U.S Impella Registry (predecessor to the currently ongoing cVAD registry), Impella support initiated prior to PCI in AMICS patients was associated with improved survival to hospital discharge compared with patients who received Impella support post-PCI.12 In addition, a multicenter, prospective study assessing Impella use as treatment for patients developing cardiogenic shock after cardiac surgery reported favorable results.13 Since receiving FDA pre-market approval in 2016, observational and registry data has suggested improved survival with early initiation of Impella support coupled with implementation of regional treatment algorithms and better patient selection.13,14 However, it is unclear whether contemporary device use is associated with improved survival outcomes compared to earlier experience with the device, and how patient selection, greater operator and institutional experience, and best practice CS protocols developed for implanting and monitoring the device have impacted outcomes.

Accordingly, the purpose of this study was to compare clinical characteristics and in-hospital outcomes of AMICS patients treated with Impella during its early and recent experience.

Section snippets

The United States Impella (cVAD) registry and patient population

The catheter-based ventricular assist devices (cVAD) registry is a prospective, observational, multicenter registry designed to monitor the real-world safety and performance of Impella heart pumps as mechanical circulatory support during PCI. The predecessor to the cVAD registry, a retrospective registry known as USpella, was initiated in 2009.15 The registry design was changed from retrospective to prospective in 2017 to accommodate for the FDA requirement of post-market and post-approval

Baseline characteristics

A total of 649 patients with AMICS were evaluated for this analysis: 291 patients who received hemodynamic support with Impella before its pre-market approval (December 2007 to June 2014, early cohort) and 358 recent patients enrolled in the post market approval period (January 2017 to August 2019, recent cohort). Demographic and comorbidity characteristics of these patients are shown in Table 1. The mean age of patients was similar in the 2 cohorts (65 ± 13 y vs 64 ± 12 y in the early and

Discussion

In this retrospective analysis of clinical characteristics and acute outcomes in AMICS patients treated in early and recent experience with Impella pVADs, we observed that several baseline and procedural characteristics have evolved with greater experience with Impella patient selection and technique. Several of these factors along with improvement in system of care for cardiogenic shock patients have significantly impacted in-hospital mortality rates, with anoxic brain injury, baseline renal

Limitations

Some limitations should be considered when interpreting the current study. Given the observational, retrospective nature of this analysis, caution needs to be exercised when inferring causality. As in all observational analyses, influence of unmeasured confounders on study results cannot be ascertained. We cannot provide insights into the specific mechanisms of lower observed mortality in the recent period. Clearly, despite support for the use of Impella based on better hemodynamics with this

Funding

None

Conflict of interest

Dr Amir Kaki: Proctor and speaker for Abiomed. Dr William O'Neill: Consultant to Edwards and Abiomed. Dr Navin K. Kapur: Speaker honoraria/consulting from Abbott, Abiomed, Boston Scientific, LivaNova, Medtronic, Precardia and Research grants from Abiomed and Boston Scientific. Dr E. Magnus Ohman: Research grants: Abiomed, Chiesi: Consultant: 3D Communications, Abiomed, ACI Clinical, Cara Therapeutics, Cardinal Health, Faculty Connection, Imbria, Impulse Medical, Janssen Pharmaceuticals,

Translational perspective

The use of Impella in patients with acute myocardial infarction and cardiogenic shock (AMICS) during recent years was associated with lower observed in-hospital mortality that was mostly related to patient characteristics on admission, such as anoxic brain injury and cardiac arrest, suggesting better patient selection in addition to changes in processes of care for these patients. In depth understanding of these factors associated with lower mortality has the potential to improve outcomes of

Acknowledgments

No extramural funding was used to support this work. The authors are solely responsible for the design and conduct of this study, all study analyses, the drafting and editing of the paper and its final contents. Dana Bentley, MWC, provided auxiliary medical editing services and writing assistance funded by the device manufacturer, in accordance with Good Publication Practice. Data management and statistical analyses were performed by ABIOMED.

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