Determinants of Early and Late In-Hospital Mortality After Acute Myocardial Infarction: A Subanalysis of the OBTAIN Registry

Abstract

Background: Predictors of in-hospital mortality after myocardial infarction (MI) have been reported dichotomously: survival vs death. Predictors of time from admission to death have not been reported.

Methods: A total of 7335 patients were enrolled in a prospective multicentre registry of acute MI. In-hospital mortality was classified by time from admission as acute (≤ 2 days), subacute (3 to 7 days), late (8 to 14 days), and very late (≥ 15 days) to identify factors associated with time to death in patients who died before discharge. Patient and MI characteristics, in-hospital interventions, and electrocardiographic findings were screened for differences in time to in-hospital death.

Results: In-hospital death affected 351 patients (4.8%). Mean age was 72.0 ± 12.4 years, and 40.5% were female patients. Median survival was 5 days (interquartile range: 2-12), and 41% of in-hospital deaths occurred after 1 week. Cardiac biomarkers and ejection fraction were not related to time to in-hospital death. Previous MI, systolic blood pressure, pharmacologic therapy, and interventional treatments were different among the 4 groups. The factors associated with late in-hospital death were coronary artery bypass graft surgery (CABG), new-onset atrial fibrillation or flutter, heart failure or pulmonary edema, bleeding, and lung disease. Acute and subacute in-hospital death was associated with ST-elevation MI, lower systolic blood pressure, and cardiac arrest on admission. CABG was performed in 12% of post-MI patients who died in hospital.

Conclusions: Clinical risk factors for in-hospital mortality evolve over time immediately after acute MI. Understanding the time-dependent risk factors may allow for the development of new approaches to curtail the "later" in-hospital mortality.