A study of management and biochemical outcomes in AMI patients supported with different mechanical devices in a single center

Abstract

Introduction: Patients with myocardial infarction (MI) and cardiogenic shock (CS) have poor outcomes in terms of morbidity and mortality. Many devices act as a ‘bridge’ in case of cardiogenic shock, by providing circulatory support and buy time so that the patient either recovers or receives a transplant or a long-term device. Materials and methods: This is a retrospective observational study where all patients (n = 286) getting admitted for MI and CS were included. The different variables are compared across the three groups [extracorporeal membrane oxygenation (ECMO), Intra-aortic balloon pump (IABP) and IABP + ECMO]. The fourth group (Impella) had only 6 patients and no statistical analysis has been done for the same, to avoid skewness of results. Results: There are a total of 286 patients in the study out of which ECMO was used in 99 patients, IABP in 138 patients, both IABP and ECMO in 43 patients, and Impella in 6 patients. The patients differed in terms of diagnosis category, pre-existing hypertension, pre-existing diabetes, pre-existing hyperlipidemia, pre-existing heart failure, and other co-morbidities. The groups also differed in terms of the cardiac findings like heart rate, left ventricular end-diastolic diameter (LVED), and left ventricular ejection fraction (LVEF). Stents were implanted more commonly among the IABP (22.5%) and IABP + ECMO group (25.6%) as compared to the ECMO group (6.1%), and the difference was statistically significant (p Value = 0.0012). The median time for device usage in ECMO group was 147 h, as compared to 130 h among IABP group and 144 h among IABP + ECMO group, and the difference was statistically significant between the ECMO and IABP group (p Value = 0.047). The median time for breathing machine assisted ventilation was also highest in the ECMO group (262 h), as compared to IABP (86 h) and IABP + ECMO group (177 h). Patients in the ECMO group had the higher heart rate than patients in IABP group (median heart rate: 95 vs 86 beats per minute). Left ventricular ejection fraction was highest in the IABP group (41% in IABP group Vs 24.5% in ECMO group & 35% in IABP + ECMO group). Conclusion: Though the three groups (IABP, ECMO and ECMO + IABP) were heterogenous, there was a clear advantage in terms of outcomes in the group in which more than one device was used. In conclusion we can say that all three devices have their own advantages and disadvantages, and they have a distinct hemodynamic footprint and thus should be used after detailed assessment of the patient.

Keywords

• Mechanical circulatory devices
• AMI-CS
• Outcomes
• Impella
• IABP
• ECMO