Mortality differences among patients with in-hospital ST-elevation myocardial infarction

Background: In-hospital ST-elevation myocardial infarction (STEMI) is associated with a higher mortality rate than out-of-hospital STEMI. Quality measures and universal protocols for treatment of in-hospital STEMI do not exist, likely contributing to delays in recognition and treatment.

Hypothesis: To analyze differences in mortality among three subsets of patients who develop in-hospital STEMI.

Methods: This was a multicenter, retrospective observational study of patients who developed in-hospital STEMI at six United States medical centers between 2008 and 2017. Patients were stratified into three groups: (1) cardiac, (2) periprocedure, or (3) noncardiac/nonpostprocedure. Outcomes examined include time from electrocardiogram (ECG) acquisition to cardiac catheterization lab arrival (ECG-to-CCL) and survival to discharge.

Results: We identified 184 patients with in-hospital STEMI (mean age 68.7 years, 58.7% male). Group 1 (cardiac) patients had a shorter average ECG-to-CCL time (69 minutes) than group 2 (periprocedure, 215 minutes) and group 3 (noncardiac/nonpostprocedure, 199 minutes). Compared to group 1, survival to discharge was lower for group 2 (OR 0.33, P = .102) and group 3 (OR 0.20, P = .016). After adjusting for prespecified covariates, the relationship between group and survival showed a similar trend but did not reach statistical significance.

Conclusions: Patients who develop in-hospital STEMI in the context of a preceding procedure or noncardiac illness appear to have longer reperfusion times and higher in-hospital mortality than patients admitted with cardiac diagnoses. Larger studies are warranted to further investigate these observations. Health systems should place an increased emphasis on developing quality metrics and implementing quality improvement initiatives to improve outcomes for in-hospital STEMI.