MI After Non–ST-Segment Elevation Acute Coronary Syndrome

Study Questions:

What are the risk and predictors of spontaneous myocardial infarction (MI) among patients with non–ST-segment elevation myocardial infarction (NSTEMI) acute coronary syndrome (ACS) who are treated with medical therapy?

Methods:

The investigators used data from 9,294 patients with NSTEMI/unstable angina ACS randomized in the TRILOGY ACS trial to assess predictors of MI. All patients were treated medically for the index presentation.

Results:

A total of 695 patients had a spontaneous MI over 30 months (10.7%). Of these, 8.2% were STEMIs and 86.8% were NSTEMIs. Predictors of spontaneous MI were older age, index presentation with NSTEMI, diabetes mellitus, absence of pre-randomization angiography, and abnormal renal function. The authors developed a risk model calculator using these factors, which had modest discrimination, with a c statistic of 0.73.

Conclusions:

Among patients with NSTEMI ACS who are treated medically, the risk of spontaneous MI is approximately 10% over the subsequent 30 months, and can be predicted based on clinical risk factors.

Perspective:

A significant proportion of patients with NSTEMI do not have severe coronary artery disease, and this study suggests that they continue to be at risk for future events despite good medical therapy. The authors developed a calculator to predict which patient is likely to have a subsequent event, but the modest discrimination of the model and the low incidence of events makes it difficult to endorse use of this calculator to risk stratify patients for more (or less) aggressive risk factor modification. All of these patients need to be treated with aggressive risk factor modification until tools (or models) with better negative predictive power can be developed.

Clinical Topics: Acute Coronary Syndromes, Invasive Cardiovascular Angiography and Intervention, Interventions and ACS, Interventions and Coronary Artery Disease, Interventions and Imaging, Angiography, Nuclear Imaging

Keywords: Acute Coronary Syndrome, Angina, Unstable, Angiography, Coronary Artery Disease, Diabetes Mellitus, Myocardial Infarction, Renal Insufficiency, Risk Factors


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