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Revised Guidelines Issued for the Management of Unstable Angina and Non-ST-Elevation Myocardial Infarction
Coronary artery disease (CAD) is the leading cause of death in the United States, and UA and NSTEMI are acute manifestations of this condition. In 2004, the National Center for Health Statistics reported 669,000 hospitalizations for UA and 896,000 for myocardial infarction. Unstable angina, which causes chest pain and discomfort, occurs when a coronary artery is partially blocked. Myocardial infarction, or heart attack, occurs when a coronary artery is completely blocked, cutting off blood flow to the heart resulting in death of heart muscle.
The ability to detect and treat these conditions earlier has greatly improved over the last several years. “New evidence from pivotal trials over the past five years has been gathered together in these guidelines to give physicians up-to-date and detailed information on which treatment options will provide the best possible outcomes for their patients,” said Nanette K. Wenger, M.D., F.A.C.C., F.A.H.A., a member of the guidelines writing committee and professor of medicine in the Division of Cardiology at Emory University School of Medicine in Atlanta. “This is a major educational document for health professionals, and I trust it will become part of the core teaching for medical students, residents and graduate physicians.”
The guidelines, which were last published in 2002, have been developed for cardiovascular specialists, emergency room physicians and healthcare professionals who evaluate and treat patients with acute coronary syndrome. They focus on the diagnosis, treatment and management of patients with UA and the closely related condition of NSTEMI.
The 2002 guidelines recommended an early invasive strategy – diagnostic angiography and revascularization – as the way to treat UA/NSTEMI patients. The revised guidelines differentiate more extensively between high- and low-risk UA/NSTEMI groups, and recommend an early invasive strategy for unstable and high risk patients, with an initial conservative (non-invasive) strategy – stress test, echocardiogram or radionuclide study – as a possible treatment option in stabilized UA/NSTEMI patients and low risk patients. Risk status is determined by risk scores.
For clinical practitioners, the revised guidelines emphasize secondary prevention, recommendations that should be continued after the UA/NSTEMI patient is discharged from the hospital to reduce risk of a recurrent heart attack. “We are emphasizing the use of ACE inhibitors---drugs that protect the muscle--- and prescribing aldosterone receptor blockade, a new drug category that wasn’t available previously for people with heart failure,” said Wenger. “High-dose antioxidant vitamin supplements such as beta carotene, vitamins E and C and folic acid for secondary prevention are no longer recommended because results from clinical trials have shown no benefit and possible harm.” There is also a greater emphasis on smoking cessation.
Also new in the guidelines is the call for more intense lipid and blood pressure control. More stringent LDL cholesterol-lowering therapy and blood pressure management is recommended for UA/NSTEMI patients. LDL (“bad” cholesterol) should be lower than 100 mg/dL and ideally reduced to 70 mg/dL. Blood pressure should be lower than 140/90 and for those with diabetes or chronic kidney disease, a reading lower than 130/80 is recommended.
Because platelets are thought to play a key role in recurrent heart attack, the anti-platelet therapy clopidogrel is now recommended for at least one year after placement of a drug-eluting stent and shorter term for bare metal stent and with medical therapy. “In addition we are emphasizing the value of intensive, long-term platelet therapy,” said Wenger.
Additional updates to the guidelines include recommendations to discontinue the use of hormone replacement therapy in postmenopausal women; add troponin biomarkers as markers of cardiac damage and B-type natriuretic peptide (BNP) markers as potentially useful for cardiac risk assessment; and stop the usage of non-steroidal anti-inflammatory drugs (NSAIDS) for all UA/NSTEMI patients during hospitalization.
Source: American College of Cardiology and the American Heart Association