Hospitals with lower risk-adjusted in-hospital mortality rates (RAMR) among patients with cardiogenic shock following acute myocardial infarction (AMI) demonstrated higher rates of revascularization and better adherence to associated process measures, but did not exhibit structural factors associated with decreased mortality among this patient population, according to a study published in the American Journal of Cardiology.

Including 16,337 patients (median age 66, 33% women) across 440 sites (median RAMR 33.4%) captured from 2015 through 2018 by the ACC’s Chest Pain – MI Registry, Amit Saha, MD, et al., sought to evaluate characteristics of high-performing hospitals in treating cardiogenic shock after AMI. For comparison, sites were stratified across tertiles of RAMR: low (RAMR 0.0-28.8%), medium (RAMR 28.9-37.9%) and high (RAMR 40.0%-71.3%).

After risk adjustment, the authors found that lower-RAMR sites treated patients with fewer comorbidities, performed more revascularization (92.7% vs. 90.6% vs. 85.9%; p<0.001), and demonstrated better adherence to other associated process measures.  

However, factors associated with lower in-hospital mortality and likely reflective of greater institutional knowledge or resources, such as left ventricular assist device capability (odds ratio [OR], 0.78 [0.67-0.92]; p=0.002), a greater proportion of patients undergoing revascularization (OR, 0.93 [0.88-0.98]; p=0.006) and higher volume of AMI patients with cardiogenic shock (OR, 0.95 [0.91-0.99]; p=0.009) were not observed more frequently at low-RAMR sites.

“Despite the strength of the utilized stratification model, there were likely multiple confounders affecting mortality across sites, such as preadmission comorbidities,” write the authors. They note that their findings “highlight the difficulty in capturing the heterogeneity and variable severity of [cardiogenic shock following AMI] and the consequent challenge in adequately defining the high-performing shock center despite using a high-quality national database.”

Clinical Topics: Heart Failure and Cardiomyopathies, Acute Heart Failure

Keywords: National Cardiovascular Data Registries, Chest Pain MI Registry, Shock, Cardiogenic, Myocardial Infarction