Clinical Investigation
Acute Ischemic Heart Disease
Differences in symptom presentation and hospital mortality according to type of acute myocardial infarction

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Background

Chest pain/discomfort (CP) is the hallmark symptom of acute myocardial infarction (MI), but some patients with MI present without CP. We hypothesized that MI type (ST-segment elevation MI [STEMI] or non-STEMI [NSTEMI]) may be associated with the presence or absence of CP.

Methods

We investigated the association between CP at presentation and MI type, hospital care, and mortality among 1,143,513 patients with MI in the National Registry of Myocardial Infarction (NRMI) from 1994 to 2006.

Results

Overall, 43.6% of patients with NSTEMI and 27.1% of patients with STEMI presented without CP. For both MI type, patients without CP were older, were more frequently female, had more diabetes or history of heart failure, were more likely to delay hospital arrival, and were less likely to receive evidence-based medical therapies and invasive cardiac procedures. Multivariable analysis indicated that NSTEMI (vs STEMI) was the strongest predictor of atypical symptoms (adjusted odds ratio [95% CI], 1.93 [1.91-1.95]). Within the 4 CP/MI type categories, hospital mortality was highest for no CP/STEMI (27.8%), followed by no CP/NSTEMI (15.3%) and CP/STEMI (9.6%), and was lowest for CP/NSTEMI (5.4%). The adjusted odds ratio of mortality was 1.38 (1.35-1.41) for no CP (vs CP) in the STEMI group and 1.31 (1.28-1.34) in the NSTEMI group.

Conclusions

Hospitalized patients with NSTEMI were nearly 2-fold more likely to present without CP than patients with STEMI. Patients with MI without CP were less quickly diagnosed and treated and had higher adjusted odds of hospital mortality, regardless of whether they had ST-segment elevation.

Section snippets

Patient population and data collection

The NRMI was funded by Genentech, Inc, and represents the largest registry of its kind in the world, which has enrolled 2,160,671 patients admitted with MI at 1,977 hospitals from 1994 to 2006. In the NRMI, the diagnosis of acute MI was based on a clinical presentation consistent with acute MI at the time of hospitalization and was determined by each local hospital. This primarily involved an International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis code of

Study population

A total of 1,143,513 patients with MI were eligible. The average age was 69.6 years, and 42% were female. About half of our study population presented with STEMI (n = 565,195) and the other half with NSTEMI (n = 578,314). Among patients with STEMI, more than one fourth presented without chest pain/discomfort (Figure 1). In patients with NSTEMI, more than two fifths presented without chest pain/discomfort.

Baseline and presenting characteristics

Patients with STEMI and chest pain/discomfort were, on average, younger than those without

Discussion

We present the largest study to date examining atypical presentation by classification of MI type and associated hospital mortality. Among patients with STEMI, just more than one fourth presented without chest pain/discomfort compared with more than two fifths of patients with NSTEMI. In an adjusted model accounting for sociodemographics, coronary heart disease risk factors, and medical history, patients with NSTEMI had almost twice the odds compared with patients with STEMI of having MI

Conclusions

Hospitalized patients with NSTEMI were almost 2-fold more likely to present without chest pain/discomfort than patients with STEMI. In both STEMI and NSTEMI, patients without chest pain/discomfort received fewer guideline-based potentially lifesaving interventions upon hospitalization and had significantly higher crude and adjusted mortality than patients with chest pain/discomfort. More than one-quarter of patients with STEMI presented with atypical symptoms. Because patients with STEMI are

Disclosures

Paul D. Frederick is an employee of ICON, a contract research organization that receives research funding from the pharmaceutical industry. He was paid by Genentech, Inc, to provide biostatistical and analytic services. George Sopko is an employee of the Health and Human Services, National Institutes of Health, and National Heart, Lung, and Blood Institute, and the material presented should not be taken as representing the viewpoint of these organizations.

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Catarina Kiefe reports receiving partial funding from the National Institutes of Health (grants U01HL 105268 and U54 RR 026088).

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For the NRMI Investigators.

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