New Non-ST-Elevation ACS Guidelines: New Title, New Approach

Marlene Busko

September 29, 2014

DALLAS, TX and WASHINGTON, DC — The American Heart Association and the American College of Cardiology have issued a guideline for the management of patients with non-ST-elevation acute coronary syndromes (NSTE-ACS)[1], which addresses the "landmark advances" in the care of these patients since the 2007 guidelines for the management of patients with unstable angina/non-ST-elevation MI were published[2].

The guidelines were published online September 23, 2014 in Circulation and the Journal of the American College of Cardiology.

Although focused updates have been issued, "this is the first full revision since the 2007 guideline," writing committee chair Dr Ezra A Amsterdam (University of California School of Medicine Davis and Sacramento, CA) told heartwire . It covers the new challenges and opportunities posed by emerging diagnostic and therapeutic strategies.

The first thing that has changed is the name. The new title, "Non-ST-elevation acute coronary syndromes," emphasizes the pathophysiological continuum between unstable angina and non-ST-elevation MI (NSTEMI). Moreover, patients who present with unstable angina or NSTEMI can be indistinguishable. Thus, they are considered together in this new guideline.

To more clearly convey this physiology-based patient-management approach, the guideline has replaced the term "initial conservative management" with "ischemia-guided strategy," Amsterdam noted.

One of the most rapidly evolving areas in the care of patients with non-ST-elevation ACS is the use of cardiac troponin, the authors write. Even though highly sensitive troponin assays are not yet available in the US, the sensitivity of troponin assays has been steadily increasing. "A promising approach to improve the diagnostic accuracy for detecting myocardial necrosis is measurement of absolute cardiac troponin change, which may be more accurate than the traditional analysis of relative alterations," the authors suggest.

"We should have a truly high-sensitive troponin assay [in the US] within the next year or so, which may radically change patient management," Amsterdam speculated. "Some hospitals still use traditional 'rule-out-MI' procedures . . . [that are] very inefficient and very costly," he noted.

The guideline provides summary tables with up-to-date, easily accessible information. For example, it includes information based on the 2013 cholesterol-management guidelines. "We agree on the use of high-intensity statins for patients with overt cardiovascular disease," Amsterdam said.

For patient risk stratification, the guideline advocates the use of tools such as the TIMI risk score and the Global Registry of Acute Coronary Events (GRACE) risk score. It also provides information about how to identify low-risk patients with chest pain who are not having an acute coronary syndrome and who may safely be discharged early.

There is a more robust section on posthospital discharge, based on new knowledge gained in the past seven years. "A key issue is to make patients' subsequent survival optimal," which includes patient education and adherence to recommended care, according to Amsterdam. Referral to cardiac rehabilitation programs is strongly recommended.

The guideline also highlights evidence gaps, including a need for more data from patients older than 75 and women, who make up most of the special populations of patients with non-ST-elevation ACS. "An unmet need is to more clearly distinguish which older patients are candidates for an ischemia-guided strategy compared with an early invasive management strategy. An appreciable number of patients with NSTE-ACS have angiographically normal or nonobstructive CAD, a group in which women predominate," the authors write.

Amsterdam also pointed out that it remains a challenge to balance the blood-thinning effects of the newer more potent anticoagulants that reduce the risk of major adverse cardiac outcomes vs the increased risk of bleeding. "Patients with atrial fibrillation who develop non-ST-elevation acute coronary syndrome and receive a coronary stent are the population at risk from indicated triple anticoagulant/antiplatelet therapy," the authors note. Elimination of aspirin may modify the risk, but this requires confirmation, they add.

This type of problem is faced by cardiologists every day and is an example of how clinical judgment should always be used to supplant information gleaned from guidelines, Amsterdam said.

There are also important changes to the level of recommendation for different antiplatelet drugs. For the first time, the guideline specifies that it is reasonable to use the P2Y12 inhibitor ticagrelor (Brilinta, AstraZeneca) rather than clopidogrel in patients with NSTEMI ACS who undergo an early invasive or ischemia-guided strategy or who receive a coronary stent (class IIa recommendation).

The guideline writers conclude with a reminder of the need for individualized patient care. "The science of medicine is rooted in evidence, and the art of medicine is based on the application of this evidence to the individual patient."

Amsterdam has no conflicts of interest. Disclosures for the coauthors are listed in the article.

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