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Guidelines: Managing Patients with Unstable Angina and Non-ST-Segment-Elevation MI

The AHA and ACC have updated their 2000 guidelines to keep pace with rapid changes in therapy and management options for these patients.

Sponsoring Organizations: the American College of Cardiology and the American Heart Association

Background and Purpose: Since 2000, when these guidelines were last issued, there have been rapid advances in antiplatelet, antithrombotic, and cholesterol-lowering therapy, along with further evidence supporting invasive management for certain subgroups of patients with unstable angina and non-ST-segment-elevation MI (UA/NSTEMI). This revision reflects those new realities.

Key Points:

1. The guidelines continue to emphasize risk stratification in the initial evaluation and treatment of UA/NSTEMI patients. A combination of history, clinical findings, ECG findings, and cardiac markers enable differentiation into low-, intermediate-, and high-risk patient groups. New to this update is an acknowledgement of multivariable risk scores, which may allow more quantitative risk stratification.

2. Among the class I recommendations for antiplatelet therapy are initiating clopidogrel plus aspirin in the hospital and continuing them for at least 1 month (and up to 9 months), both in conservatively managed patients and in most who undergo PCI (see Journal Watch Cardiology Sep 28 2001 for reviews of the CURE trial and its PCI substudy). Clopidogrel should be withheld for at least 5 days (if possible) in patients for whom CABG is planned. Clopidogrel is the preferred thienopyridine (over ticlopidine).

3. Using low-molecular-weight heparin (LMWH) or unfractionated heparin (UFH) remains a class I recommendation. However, the LMWH enoxaparin is now preferred to UFH, unless early CABG is planned.

4. Using platelet glycoprotein IIb/IIIa inhibitors is a class I recommendation for patients in whom catheterization and PCI are planned. Class II (somewhat less well-supported) recommendations include eptifibatide or tirofiban, but not abciximab, when PCI is not planned in high-risk (class IIa) and lower-risk (class IIb) patients.

5. On the basis of data from the TACTICS-TIMI 18 trial (Journal Watch Cardiology Aug 3 2001), new criteria that can be used to support an early invasive management strategy (versus a conservative one) include recurrent angina/ischemia at rest, elevated troponin level, and new ST-segment depression.

6. Recommendations for long-term medical therapy have been updated to include clopidogrel plus aspirin for 9 months, ACE inhibition (even in patients with normal LV function), and predischarge initiation of lipid-lowering therapy according to NCEP guidelines.

Comment: These guidelines are a comprehensive, well-referenced source for evaluating and treating UA/NSTEMI patients, with new recommendations on how and when to use clopidogrel, enoxaparin, and an early invasive management strategy. Unfortunately, because of a lack of evidence, the authors could make few recommendations about combined therapy with the many potent new antiplatelet and antithrombotic therapies in either medical or invasive management.

— Howard C. Herrmann, MD

Published in Journal Watch Cardiology April 26, 2002

Citation(s):

Braunwald E et al. ACC/AHA guideline update for the management of patients with unstable angina and non-ST-segment elevation myocardial infarction: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on the Management of Patients with Unstable Angina). 2002. http://www.acc.org/clinical/guidelines/unstable/unstable.pdf