Physician's Weekly Article - Welcome Changes: Updated Guidelines for Managing Unstable Angina & NSTEMI

       Newly released guidelines offer clinicians an expanded group of diagnostic and therapeutic options to effectively identify and manage unstable angina and non-ST elevation myocardial infarction.

      Unstable angina (UA) and non-ST elevation myocardial infarction (NSTEMI) are acute manifestations of coronary artery disease (CAD), a leading cause of death in the United States. They are also the leading causes of emergency department visits and hospitalizations. The ability to detect and treat UA/NSTEMI earlier has greatly improved over the past several years, resulting in improved outcomes. However, methods to improve the recognition and treatment of these conditions are still needed to significantly reduce morbidity and mortality rates.

      Beginning in 1994, the American College of Cardiology (ACC) and the American Heart Association (AHA) jointly released guidelines for the management of patients with UA/NSTEMI. Since that time, significant advances in knowledge about methods to diagnose and manage UA/NSTEMI have occurred. As such, the ACC and AHA collaborated again to update the guidelines to incorporate new scientific advances. The updated guidelines were published in the August 15, 2007 issue of the Journal of the American College of Cardiology.

      In developing the new guidelines, a panel of renowned health professionals and scientists reviewed the highest quality research published since 2002 addressing important topics related to UA/NSTEMI. “In a field in which the science continually evolves,” says A. Michael Lincoff, MD, who co-authored the guidelines, “it’s critical to consistently reevaluate clinical evidence and consider expert opinion. The updated guidelines include revisions to and confirmation of the most appropriate methods to diagnose and treat patients with UA/NSTEMI.”

      Refining Old Strategies

      The 2007 guidelines introduce a number of new recommendations for initial diagnostic testing as well as choice and duration of antiplatelet therapy. In addition, new anticoagulants and other agents that, through numerous clinical trials, have been proven to be of no benefit or possible harm are also evaluated in the guidelines (Table 1). “The new guidelines represent a refinement of strategy,” Dr. Lincoff explains. “There is now a more defined shift. The 2002 guidelines recommended an early invasive strategy, one that encouraged the use of diagnostic angiography and revascularization, as the optimal way to treat UA/NSTEMI patients. The 2007 guidelines now encourage physicians to conduct an initial risk assessment using an overall clinical risk score and biomarkers to determine if the patient is at low- or high-risk [Table 2]. Once the level of risk is established, the mission is to then choose a treatment pathway accordingly. Results from the Invasive Versus Conservative Treatment in Unstable Coronary Syndrome trial, or ICTUS, suggest that an initially conservative, noninvasive strategy may be appropriate for low-risk patients or for those who have been stabilized.”

      Another major shift represented by the updated guidelines is the incorporation of medications before, during, and after a UA/NSTEMI diagnosis. Bivalirudin and fondaparinux have received a Class I indication by the 2007 guidelines for adjunctive use with antiplatelet therapy in patients who receive an invasive treatment strategy. Unfractionated heparin and enoxaparin have received Class I indications in patients undergoing either invasive or conservative strategies, but the guidelines state that fondaparinux is preferred over these other agents in conservatively managed patients who are at increased risk of bleeding. When an initial conservative strategy is selected in UA/NSTEMI patients, enoxaparin or fondaparinux are recommended.

      More stringent lipid and blood pressure control for UA/NSTEMI patients is also strongly encouraged by the guidelines. LDL-cholesterol should be lower than 100 mg/dL and ideally reduced to 70 mg/dL. Blood pressure should be lower than 140/90 mm Hg for those with diabetes or chronic kidney disease; blood pressure lower than 130/80 mm Hg is optimal.

      Identifying Unbeneficial & Harmful Agents

      The new ACC/AHA guidelines also reaffirm agents that have been proven to be of no benefit and potential harm to UA/NSTEMI patients, including antioxidant vitamin supplements (eg, beta-carotene, vitamin E and C, and folic acid), hormone replacement therapy in post-menopausal women, and nonsteroidal anti-inflammatory drugs (except for aspirin) during hospitalization. Dr. Lincoff notes that “the recommendations for not using these agents doesn’t come out of the blue. Rather, these guidelines are based on what we have seen in patterns over time. We’re simply using the update to reinforce their nonuse among patients with UA/NSTEMI.”

      Looking Ahead

      Adverse outcomes from UA/NSTEMI have fallen dramatically over the past decade, and Dr. Lincoff says that it is hoped that more updates of evidence-based guidelines will further advance clinician knowledge and improve quality of care for patients with UA/NSTEMI. “We’ll continue to use national registries and other investigations to evaluate adherence to guidelines, utilization of different therapies, and their impact on clinical outcomes related to UA/NSTEMI in the future.”

      Dr.Lincoff has indicated to Physician’s Weekly that he has received grants/research support from Alexion Pharm, Amer Bioscience, AstraZeneca, Atherogenics, Biosite, Centocor, Converge Medical, Cordis, Dr. Reddy’s Laboratory, Eli Lilly, GlaxoSmithKline, Glaxo Wellcome, Guilford, Medtronic, Novartis, Pfizer, Pharmacia Upjohn, Philips, Orphan Therapeutic, Sankyo, Sanofi, Scios, Takeda America, The Medicines Company, and Vasogenix.