Medical Device Daily

U.S. heart experts are recommending a two-pronged approach to treating patients with chest pain or heart attacks caused by blocked arteries, according to the revised guidelines for the management of patients with unstable angina (UA) or non-ST-elevation myocardial infarction (NSTEMI).

The guidelines were developed for cardiovascular specialists, emergency room physicians and healthcare professionals who evaluate and treat patients with acute coronary syndrome.

Issued jointly by the American College of Cardiology (ACC; location) and the American Heart Association (AHA; Dallas), the revised guidelines tweak 2002 guidelines, which recommended an early invasive strategy — diagnostic angiography and revascularization — as a way to treat UA and NSTEMI patients.

According to Elliott Antman, MD, a member of the guidelines writing committee and a professor of medicine in the cardiovascular division at Brigham and Women’s Hospital, Harvard Medical School (Boston), one thing that has changed since the guidelines were previously published in 2002 is that there are a number of medications that are new or for which heart experts now have more information than they did five years ago.

“We focused on those individuals for whom a non-invasive strategy should be performed and those for whom a more conservative strategy is appropriate,” Antman told Medical Device Daily .

Thus, 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, but an initial non-invasive strategy —stress test, echocardiogram or radionuclide study — as a possible treatment option in stabilized and low risk patients. Risk scores determine risk status.

“Undertaking a catheter and possibly doing bypass surgery or [implanting] a stent is not a trivial procedure, and we don’t want to put the patient at risk for potential complications if they are not going to benefit from that as much,” Antman said.

In general, Antman said, low-risk women, more so than men, should probably be handled medically rather than with an invasive procedure, because they tend to be smaller, anatomically.

Coronary artery disease is the leading cause of death in the U.S., and UA and NSTEMI are acute manifestations of this condition, according to the physician groups. 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 the death of heart muscle.

The ability to detect and treat these conditions earlier has greatly improved over the last several years, according to the ACC and AHA.

“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 Wenger, MD, a member of the guidelines writing committee and a professor of medicine in the division of cardiology at Emory University School of Medicine (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.”

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,” Wenger said. “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 the guidelines emphasize the value of intensive, long-term platelet therapy, Antman told MDD.

Additional updates to the guidelines include recommendations to discontinue the use of hormone replacement therapy in postmenopausal women; the addition of 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.

The guidelines will be published the current (Aug. 14) issues of the Journal of the American College of Cardiology, and Circulation: Journal of the American Heart Association.

The American College of Cardiology is a 34,000-member non-profit medical society and bestows the credential Fellow of the American College of Cardiology upon physicians who meet its stringent qualifications.

Founded in 1924, the American Heart Association is the nation’s oldest and largest voluntary health organization dedicated to reducing disability and death from diseases of the heart and stroke.