Treatment and Outcomes in Patients With Myocardial Infarction Treated With Acute β-Blocker Therapy: Results From the American College of Cardiology’s NCDR®
What is the association between beta-blocker (BB) use and in-hospital outcomes stratified by type of myocardial infarction (MI) and number of risk factors for cardiogenic shock?
The investigators examined acute (≤24 hours) BB use in 34,661 patients with ST-elevation MI (STEMI) and non–STEMI (NSTEMI) included in the NCDR® ACTION Registry®-GWTG™ (291 US hospitals) between January 2007 and June 2008. Patients with contraindications, who did not receive BBs, or with missing data were excluded. They analyzed the use and impact of BBs stratified by variables associated with increased risk for shock specified in the recent guidelines: age >70 years, symptoms >12 hours (STEMI patients), systolic blood pressure <120 mm Hg, and heart rate >110 bpm on presentation.
Among patients without contraindications, at least one high-risk variable was found in 45% of STEMI and 63% of NSTEMI patients. In-hospital complications including cardiogenic shock, mortality, and the composite outcome of shock or mortality were significantly increased, with more shock risk factors in both STEMI and NSTEMI patients. Very early use in the emergency department was associated with a significantly increased risk of shock for both STEMI and NSTEMI patients compared to patients treated later, but within 24 hours.
The authors concluded that risk factors for shock are common in STEMI and NSTEMI patients treated with early BBs.
The study found that most patients with STEMI or NSTEMI who were treated with acute BB treatment had at least one risk factor for cardiogenic shock, as defined by current guidelines. Very early BB use either in the emergency department or before primary percutaneous coronary intervention was also associated with the development of cardiogenic shock and the combination of shock or death when compared to patients treated later, but within 24 hours of presentation. The data support current guidelines, which recommend that caution should be used when giving BBs to high-risk patients early during the initial acute care period, and waiting for patient stabilization before starting a BB appears prudent.
Keywords: Shock, Cardiogenic, Myocardial Infarction, Emergency Service, Hospital, United States, Percutaneous Coronary Intervention
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