Trends in mechanical circulatory support use and hospital mortality among patients with acute myocardial infarction and non-infarction related cardiogenic shock in the United States

Abstract

Background: Recent trends on outcomes in cardiogenic shock (CS) complicating acute myocardial infarction (AMI) suggest improvements in early survival. However, with the ever-changing landscape in management of CS, we sought to identify age-based trends in these outcomes and mechanical circulatory support (MCS) use among patients with both AMI and non-AMI associated shock.

Methods: We queried the 2005-2014 Nationwide Inpatient Sample databases to identify patients with a diagnosis of cardiogenic shock. Trends in the incidence of hospital-mortality, and use of MCS such as intra-aortic balloon pump (IABP), Impella/TandemHeart (IMP), and extra corporeal membrane oxygenation (ECMO) were analyzed within the overall population and among different age-categories (50 and under, 51-65, 66-80 and 81-99 years). We also made comparisons between patient groups admitted with CS complicating AMI and those with non-AMI associated CS.

Results: We studied 144,254 cases of CS, of which 55.4% cases were associated with an AMI. Between 2005 and 2014, an overall decline in IABP use (29.8-17.7%; ptrend < 0.01), and an uptrend in IMP use (0.1-2.6%; ptrend < 0.01), ECMO use (0.3-1.8%; ptrend < 0.01) and in-hospital mortality (44.1-52.5% AMI related, 49.6-53.5% non-AMI related; ptrend < 0.01) was seen. Patients aged 81-99 years had the lowest rate of MCS use (14.8%), whereas those aged 51-65 years had highest rate of MCS use (32.3%). Multivariable analysis revealed that patients aged 51-65 years (aOR 1.46, 95% CI 1.40-1.52; p<0.001), 66-80 years (aOR 2.51, 95% CI 2.39-2.63; p<0.01) and 81-99 years (aOR 5.04, 95% CI 4.78-5.32; p<0.01) had significantly higher hospital mortality compared to patients aged ≤ 50 years. Patients admitted with CS complicating AMI were older and had more comorbidities, but lower hospital mortality (45.0 vs. 48.2%; p < 0.001) when compared to non-AMI related CS. We also noted that the proportion of patients admitted with CS complicating AMI significantly decreased from 2005 to 2014 (65.3-45.6%; ptrend < 0.01) whereas those admitted without an associated AMI increased.

Conclusions: IABP use has declined whereas IMP and ECMO use has increased over time among CS admissions. Older age was associated with an incrementally higher independent risk for hospital mortality. Recent trends indicate an increase in both proportion of patients admitted with CS without associated AMI and in-hospital mortality across all CS admissions irrespective of AMI status.

Keywords: Balloon pump; Cardiogenic shock; ECMO; Impella; MCS; Mortality; Nationwide inpatient sample; Trends.