Outcome of patients with cardiogenic shock in acute myocardial infarction treated with Impella CP and a standardized protocol
Authors: Sramko M , Benak A , Toman J , Zelizko M , Janek B , Karmazin V , Hrncarek M , Kleissner M , Pazdernik M , Holek M , Kettner J , Kautzner J 
Published: November 2023

Abstract

Background
Recent registry data indicate improved outcome of patients with cardiogenic shock in acute myocardial infarction (AMICS) if treated with Impella CP according to a standardized protocol.

Purpose
To evaluate in-hospital and 6-months survival of patients with AMICS after implementation of a standardized protocol with early use of Impella CP.

Methods
The study compared a contemporary cohort of consecutive patients treated in our centre for AMICS with Impella CP according to an established protocol with a historical cohort of consecutive patients treated with IABP without a protocol (admissions during 5/2019 - 5/2022 vs. 1/2007 - 12/2012). The criteria for implantation of Impella included: 1.) ischemia duration of &lt;24 hours, 2.) age &lt;75 years and absence of life-limiting comorbidities, 3.) impaired left ventricular contractility with enddiastolic pressure (LVEDP) of &gt;18 mmHg, and 4.) successful percutaneous coronary intervention (PCI), urgent coronary artery bypass grafting (CABG), or potential candidacy for long-term left ventricular assist device (LVAD) in case of unattainable coronary revascularization. Excluded were patients with out-of-hospital cardiac arrest of &gt;5 minutes, mechanical complications of myocardial infarction, and patients with small diameter of access arteries. The protocol contained recommendations for early identification of AMICS, complex intensive care, pharmacotherapy, and escalation of the mechanical circulatory support. The patients in the historical cohort were retrospectively matched with the contemporary cohort by the same idication criteria except for LVEDP, which was not measured routinely. In-hospital and 6-months survival status were evaluated from collected medical records.

Results
In total, 21 patients were treated with Impella CP according to the protocol and 23 patients were treated with IABP without a protocol (age: 65 ± 10 vs. 64 ± 10 years; males: 19 [90%] vs. 20 [87%], LVEF: 27 ± 7% vs. 24 ± 6%, median [IQR] lactate: 3.7 [2.1 - 5.7] vs. 4.2 [2.2 – 9.2] mmol/l, all p-values &gt;0.2). Revascularisation was successful in 90% and 91% of the patients, respectively (PCI/CABG: 17/2 vs. 17/4). In 5 (24%) of the patients treated with Impella, the device was implanted before PCI. Subsequent addition of ECMO for refractory shock was needed in 4 (19%) of the patients in the contemporary cohort and 3 (13%) of the patients in the historical cohort. Long-term LVAD was implanted in 3 (14%) patients and 1 patient (4%), respectively. In-hospital survival was 15 (71%) in the contemporary cohort vs. 14 (61%) in the historical cohort, and 6-months survival was 15 (71%) vs. 11 (48%), respectively (p = 0.008 by log-rank test).

Conclusions
Patients with AMICS who were treated according to a standardized protocol with early implantation of Impella CP had a relatively favourable 6-months survival that was better compared to a historical cohort.