ST Elevation Myocardial Infarction Diagnosed After Hospital Admission

Study Questions:

What are the clinical characteristics, time to treatment, and clinical outcomes of patients who develop ST-segment elevation myocardial infarction (STEMI) after a hospital admission?

Methods:

This was an analysis of STEMI patients treated between March 2003 and January 2013 (following the implementation of the “Level 1 MI program,” a regional STEMI system, which standardized the protocol for transfer of STEMI patients from community hospitals without percutaneous coronary intervention [PCI] capability). Based on mode of arrival, patients were categorized as arrival via emergency medical services (EMS), self/family driven, or in-hospital presentation. The authors reported characteristics and outcomes for each of these three categories.

Results:

Of 3,795 patients enrolled into the regional Level 1 program, 83 (8.4%) patients developed STEMI after hospital admission. This was a heterogeneous group. Of the 83 patients, 25 were admitted with an acute coronary syndrome (ACS) but without initial ST-elevation, 19 were post-surgery, 11 had respiratory failure, and 8 were admitted for PCI and subsequently had either stent thrombosis (n = 7) or a post-stent dissection (n = 1). Overall, door-to-balloon (diagnostic ECG-to-balloon for in-hospital patients) times were longer for patients with in-hospital presentation compared to EMS patients (76 vs. 51 minutes; p < 0.001), but similar to self-family driven patients (76 vs. 66 minutes; p = 0.13). Those who developed STEMI after hospital admission had longer length of stay (5 vs. 3 vs. 3 days; p < 0.001) and higher 1-year mortality (16.9% vs. 10.3% vs. 7.1%; p = 0.032). Among the patients with in-hospital presentation of STEMI, those who were admitted for cardiac reasons had lower 1-year mortality rates, shorter length of stay (LOS), and shorter diagnostic ECG-to-balloon times, when compared to those who were admitted for noncardiac reasons.

Conclusions:

The minority of patients who develop STEMI after a hospital admission are a unique group of patients that have increased time to treatment, mortality, and LOS, compared to those who develop STEMI prior to hospitalization.

Perspective:

The authors presented findings that highlight a heterogeneous group of patients who develop STEMI after hospitalization and may be particularly vulnerable to delays in treatment and adverse outcomes. The analysis is limited by a single-center experience and a relatively small number of patients who actually develop STEMI after hospitalization. Nonetheless, quality efforts around standardizing the care of these patients may lead to better outcomes.

Keywords: Acute Coronary Syndrome, Myocardial Infarction, Hospitals, Community, Respiratory Insufficiency, Electrocardiography, Angioplasty, Balloon, Coronary, Percutaneous Coronary Intervention, Length of Stay, Stents, Thrombosis, Reference Standards, Hospitalization


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