How little we know: the search for a simple answer on acute beta-blocker use in the management of acute coronary syndrome

Treatment and outcomes in patients with myocardial infarction treated with acute β-blocker therapy: results from the American College of Cardiology's NCDR(®)

BACKGROUND

Although β-blockers (BBs) reduce long-term mortality in patients after myocardial infarction (MI), data regarding acute usage are conflicting.

METHODS

We examined acute (≤24 hours) BB use in 34,661 patients with ST-elevation MI (STEMI) and non-ST-segment MI (NSTEMI) included in the NCDR(®) ACTION Registry(®)-GWTG™ (291 US hospitals) between January 2007 and June 2008. Patients with contraindications or did not receive BBs or with missing data were excluded. We analyzed the use and impact of BB 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 beat/min on presentation.

RESULTS

Among patients without contraindications, at least 1 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.

CONCLUSIONS

Risk factors for shock are common in STEMI and NSTEMI patients treated with early BBs. Increasing numbers of risk factors were associated with increased risk for shock or death in patients treated with BBs. These results are consistent with current recommendations for avoiding early BB treatment for patients with acute MI.