AMA: Beta blockers underused

Recent studies confirm position

Late last year, the American Medical Association (AMA) in Dallas joined five other medical spe-cialty societies to announce a new call to action to expand the use of beta blockers to a larger group of patients than previously considered — even those at low-risk, as well as those who may not have been candidates for this therapy due to contraindications.

Since 1995, the AMArecommended beta block-ers as part of a comprehensive program to pre-vent second heart attacks for those at high risk —having conditions such as heart rhythm prob-lems, chest pain, or high blood pressure. The organization reaffirms its position that beta blockers are useful and effective for individuals at high risk for a repeat heart attack and goes a step further to point out that some contraindica-tions for the drugs may need to be reevaluated. For example, the benefits of beta blockers may outweigh their risks for patients with conditions such as asthma, diabetes, chronic obstructive pul-monary disease, or abnormal EKGs.

Skewed views of drug’s use

Even though IV beta blockers have been shown to reduce mortality, infarct size, and the incidence of complications in patients with acute myocardial infarction (AMI), many such patients — even those without contraindications — do not receive this adjunctive therapy. Investigators wanted to know if that could be because practi-tioners have a skewed view of the drug’s use.

They ran a retrospective review of 35 charts from Morristown (NJ) Hospital to determine the difference between the actual and perceived use of IV beta blockers in emergency department (ED) patients with diagnoses of AMI.1

The researchers analyzed the records to deter-mine if beta blockers were used and if any con-traindications were present. In addition, they surveyed ED physicians and cardiologists to determine their perceptions concerning the appropriate use of beta blockers in these patients.

Of the 35 participants, four patients received IV beta blockers while only 15 of the rest had con-traindications to the drug. The survey indicates ED physicians were less likely than cardiologists to use IV beta blockers in patients who were nor-motensive and not tachycardic, and tend to defer the decision to a cardiologist. The investigators concluded a written protocol for treating ED patients with AMI might increase the early use of IV bet blockers.

In a related study, beta blocker therapy was shown to improve left-ventricular function in patients with heart failure.2 The CIBIS-II investi-gators ran a 15-month randomized trial of about 2,600 patients with symptoms of heart disease who were already on diuretics or angiotensin-converting enzyme (ACE) inhibitors. The beta-blocker bisoprolol or a placebo was randomly assigned to patients. Bisoprolol significantly low-ered all-cause mortality, and the rate of sudden death before the end of the trial — 17% in placebo patients vs. 12% in bisoprolol patients. Though patients were less likely to die of any cause and there were fewer deaths due to cardiovascular problems in the patients treated with bisoprolol, the stroke rate was higher in patients on the beta blocker compared with patients on placebo.

The results apply only to patients with mild to moderate heart failure, stated Harlan Krumholz, MD, of Yale University in New Haven, CT. He called CIBIS-II a landmark study for those patients and points out that evidence is needed for benefit among patients with severe heart fail-ure, symptom-free left-ventricular dysfunction, new myocardial infarction, and older patients.

References

1. O’Bryan MM, Banas JS. AMI therapy: IV beta blockers perceived vs. actual use by cardiologists and emergency physicians. Am J Emerg Med 1998; 16:623-626.

2. Dargie HJ. The Cardiac Insufficiency Bisoprolol Study II (CIBIS-II). Lancet 1999; 353:(2) 9-13.