New guidelines address care, treatment for heart attacks

New clinical trial data on a variety of aspects of heart attack care has prompted the American College of Cardiology and American Heart Association to update portions of their joint guidelines for treating the type of heart attack called ST elevation myocardial infarction (STEMI).

The revised guidelines will be published in the Jan. 15, 2008, print issues of Circulation: Journal of the American Heart Association and the Journal of the American College of Cardiology and are available online at www. americanheart.org and www. acc.org.

Almost half a million Americans each year have a STEMI, which is caused by a completely blocked artery. STEMIs are considered the most critical type of heart attack but can be quickly recognized and treated to reduce heart damage.

“Our recommendations for the initial treatment of STEMI continue to reinforce the goal of restoring blood flow to the heart as quickly as possible,” said Elliott Antman, M.D., chair of the guideline writing group, director of the coronary care unit at Brigham and Women’s Hospital and professor of medicine Harvard Medical School. “Data show that better systems of care, leading to faster times to reperfusion, result in better outcomes for patients with STEMI. One underutilized but effective strategy for improving STEMI systems of care is to expand the use of prehospital 12-lead electrocardiography programs by emergency medical systems (EMS) that provide advanced life support. This provides the early diagnosis that can set into motion the appropriate treatment strategy.”

The recommendations clarify that the emphasis on percutaneous coronary intervention (PCI) should not obscure the importance of fibrinolytic (clot-busting) therapy. PCI, also known as angioplasty, is a procedure in which a tiny wire is inserted into the blocked area of a coronary artery and a balloon is inflated to re-open the artery and restore blood flow to the heart; a stent is frequently inserted to keep the artery propped open.

STEMI patients presenting to a hospital with PCI capability should be treated with primary PCI within 90 minutes of first medical contact as a systems goal. The 90-minute goal still stands for hospitals without PCI capability, as long as a patient can be transferred and receive treatment within the 90-minute window. However, patients who cannot be transferred to a PCI center and undergo PCI within 90 minutes should be treated with fibrinolytic therapy within 30 minutes of hospital presentation as a systems goal unless fibrinolytic therapy is contraindicated.

The update also includes clarification of which patients with STEMI are candidates for early intravenous (IV) beta-blocker therapy, now noting that IV beta-blockers should not be administered to STEMI patients who have any of the following: 1) signs of heart failure; 2) evidence of a low output state; 3) increased risk for cardiogenic shock; or 4) other relative contraindications to beta blockade (including second- or third-degree heart block, active asthma, or reactive airway disease).