Multiple changes spawn new UA/NSTEMI guidelines

September 17, 2007

The American College of Cardiology and the American Heart Association have updated their guidelines for the drug therapy used to treat patients with Unstable Angina/Non-ST-Elevation Myocardial Infarction.

"From a therapeutic point of view, several new therapies have emerged and landmark clinical trials have been published since 2002 that rendered the guidelines outdated," remarked Robert J. DiDomenico, Pharm.D., clinical assistant professor at the Colleges of Pharmacy and Medicine at the University of Illinois at Chicago. "For example, drug-eluting stents were not available when the '02 guidelines were published but are now used in the majority of percutaneous coronary intervention [PCI] cases, including patients with UA/NSTEMI," he explained. "As a result, there was a need to comment on the appropriate adjunctive therapy for those patients."

Antiplatelet therapy

"Recommendations are now being made regarding the use of NSAIDs [nonsteroidal anti-inflammatory drugs] and COX-2 inhibitors on the heels of studies demonstrating increased cardiovascular risk in patients taking these medications chronically," DiDomenico pointed out. The new guidelines state that during hospitalization for UA/NSTEMI, all patients should refrain from using NSAIDs. Other notable changes include the recommendation that hormonal replacement therapy should be discontinued in postmenopausal women and high-dose antioxidant supplements (beta-carotene, vitamins E and C), which were previously recommended for secondary prevention of UA/NSTEMI, are no longer recommended. New clinical trial evidence suggests no benefit from the supplements and even possible harm.

Smoking cessation

In addition, to decrease the risk for recurrent UA/NSTEMI, the new guide highlights the importance of smoking cessation and recommends the use of ACE inhibitors to reduce remodeling, as well as aldosterone-receptor blockers (ARBs) for heart failure. ACC/AHA has tightened the control of lipids as well, with a new LDL cholesterol target of less than 100 mg/dl and an optimal level of 70 mg/dl. Blood pressure targets are <140/90 mmHg or 130/80 mmHg in patients with diabetes or chronic renal disease.

"New antithrombotic drugs have been approved and studied in the setting of acute coronary syndrome that either were not available or had not been studied for ACS in 2002," DiDomenico explained. "For example, bivalirudin [Angiomax, The Medicines Co.] and fondaparinux [Arixtra, GlaxoSmithKline] have been shown to be safe and effective in this setting and recommendations are now provided." Both drugs are indicated as alternatives to heparin and enoxaparin (Lovenox, Sanofi-Aventis) in UA/NSTEMI for patients having early, invasive therapy, but the level of evidence with bivalirudin and fondaparinux is lower (level B), he said.

For patients at high risk for bleeding complications, the new guidelines specifically recommend fondaparinux over heparin and enoxaparin. "Furthermore, it is given a class IIa recommendation that fondaparinux (or enoxaparin) are preferred to heparin in conservatively managed patients, provided CABG [coronary artery bypass graft] surgery is not going to be performed within 24 hours," DiDomenico concluded.

The new ACC/AHA UA/STEMI guidelines can be accessed on-line at http:// http://content.onlinejacc.org/cgi/content/full/50/7/e1.