Saturday, October 27, 2007

ACC/AHA 2007 Guidelines for the Management of Patients With Unstable Angina/Non–ST-Elevation Myocardial Infarction—Executive Summary

ACC/AHA 2007 Guidelines for the Management of Patients With Unstable Angina/Non–ST-Elevation Myocardial Infarction—Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 2002 Guidelines for the Management of Patients With Unstable Angina/Non–ST-Elevation Myocardial Infarction): Developed in Collaboration With the American College of Emergency Physicians, the Society for Cardiovascular Angiography and Interventions, and the Society of Thoracic Surgeons.

Anderson JL, Adams CD, Antman EM, et al.

J Am Coll Cardiol. 2007;50:652-726.

Twenty points to remember about these guidelines are:

Initial Evaluation:

1. Patients with chest discomfort whose symptoms are not improved 5 minutes after taking nitroglycerin (NTG) are advised to call emergency medical service (EMS) before taking more NTG. Patients with chronic stable angina may take up to a maximum of three doses, 5 minutes apart, if symptoms are significantly improved by the first dose of NTG. They should still call EMS if symptoms are not resolved completely.

2. An electrocardiogram (ECG) should be performed on the patient with chest pain within 10 minutes of arrival to the emergency department (ED). Patients with chest pain should be rapidly stratified into one of four categories: noncardiac diagnosis, definite acute coronary syndrome (ACS), possible ACS, and chronic stable angina.

3. A cardiac-specific troponin is the preferred biomarker in patients presenting with symptoms consistent with ACS.

4. Patients with possible ACS, but with normal ECG and biomarkers over 12 to 16 hours should generally have a stress test performed prior to ED discharge or within 72 hours of discharge. These patients should be treated with appropriate pharmacotherapy while awaiting the stress test.

5. Patients with low probability of coronary artery disease (CAD) and possible ACS can also be evaluated by computed tomography angiography in lieu of a stress test.

Early Management:

6. Patients with hemodynamic instability or those with ongoing symptoms should be admitted to a coronary care unit, whereas others should be admitted to a step-down unit.

7. Oral beta-blockers should be instituted within the first 24 hours in absence of contraindications. Intravenous beta-blockers should only be used for specific indications and not as a routine therapy.

8. Nonsteroidal anti-inflammatory drugs (COX-1 or COX-2 inhibitors) other than aspirin (ASA) should be discontinued on admission to the hospital in a patient with ACS.

9. Use of morphine as an analgesic has been associated with a worse outcome in observational studies. The guidelines have downgraded it from a Class I to a Class IIa recommendation.

10. Antiplatelet therapy:

a. ASA should be administered to patients with ACS as soon as possible (unless contraindicated) and continued lifelong. Patients with ASA allergy or intolerance should be treated with clopidogrel.

b. Clopidogrel, in addition to ASA, should be initiated in patients in whom either a conservative or an early invasive therapy is considered, but the likelihood of surgical disease requiring early coronary artery bypass grafting (CABG) is low.

c. Upstream use of eptifibatide or tirofiban should be considered in high-risk patients and those with troponin elevation, especially if an invasive therapy is contemplated. Abciximab should not be used unless there is no appreciable delay to percutaneous coronary intervention (PCI). Abciximab can be used safely for PCI in patients who have not received upstream glycoprotein (GP) IIb/IIIa inhibitors and may be better than tirofiban in this population. GP IIb/IIIa inhibitors provide incremental benefit in patients with elevated troponin undergoing PCI even among those pretreated with clopidogrel.

11. Anticoagulant therapy:

a. In patients treated with conservative therapy, the preferred anticoagulant may be fondaparinux, enoxaparin (for 8 days or duration of hospitalization), or unfractionated heparin (UFH) (for 48 hours) (in that order).

b. In patients treated with invasive therapy, enoxaparin or UFH-based regimens have the most supporting evidence.

c. For patients undergoing CABG, ASA should be continued while clopidogrel should be stopped 5-7 days before, and low-molecule GP IIb/IIIa inhibitors stopped 4 hours before the surgery. Enoxaparin should be stopped 12-24 hours prior and fondaparinux stopped 24 hours prior to CABG, and UFH started.

d. All patients receiving intravenous GP IIb/IIIa inhibitors must also receive concomitant UFH or another antithrombotic agent.

12. Early invasive therapy is preferable in the high-risk patients with ongoing symptoms or hemodynamic instability, whereas either early invasive or conservative therapy can be used in other patients based on physician and patient preference. In patients who are stable for 12-24 hours on conservative therapy, noninvasive stress testing should be performed prior to discharge.

13. Choice of surgical versus percutaneous revascularization (similar to that in a patient with stable disease) should be determined by a patient’s anatomy, left ventricular function, and presence or absence of diabetes and other comorbidities.

14. Patients with non–ST-elevation myocardial infarction (NSTEMI) who had totally occluded vessels on angiography did not benefit from PCI in the OAT trial (similar to those with STEMI) and should not be intervened upon.

15. The risk of death or recurrent MI in patients with NSTEMI ACS is highest in the first 2 months and returns to a baseline risk of those with stable CAD by 3 months. Low-risk patients (and fully revascularized patients) should be followed up at 2-6 weeks, whereas high-risk patients should be re-evaluated within 2 weeks.

16. All patients with ACS should receive ASA, statins, beta-blockers, and clopidogrel (for at least 1 year). Angiotensin-converting enzyme inhibitors (or angiotensin-receptor blockers) should be initiated in patients with abnormal left ventricular ejection fraction, hypertension, diabetes, or heart failure. These medications are best initiated in the hospital since the likelihood that they will be continued long-term is highest. The blood pressure goal should be less than 140/90 mm Hg for all patients and less than 130/80 mm Hg for patients with diabetes mellitus or chronic kidney disease.

17. Hormone replacement therapy (HRT) should not be started in patients with ACS. Patients on HRT at the time of ACS should be advised to discontinue it.

18. Patients with diabetes should be treated with aggressive glucose control while hospitalized. Other diagnostic and therapeutic interventions should be in a manner similar to those of nondiabetics.

19. Special attention to drug dosing and altered pharmacodynamics is warranted while treating the elderly and patients with renal impairment.

20. Return to activity should be guided by an exercise tolerance test. Exercise training can begin within 1-2 weeks after coronary revascularization. Patients should be encouraged to walk (or engage in other physical activity) for 30-60 minutes daily. Patients with uncomplicated NSTEMI ACS can return to driving within 1 week of discharge unless prohibited by State law. Patients with complicated MI should delay driving for 2-3 weeks. Hitinder S. Gurm, M.B.B.S., F.A.C.C.

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