Guideline released on management of non-ST-elevation acute coronary syndromes

The American Heart Association (AHA) and the American College of Cardiology (ACC) released the “2014 Guideline for the Management of Patients with Non-ST-Elevation Acute Coronary Syndromes” (NSTE-ACS) last week.

The guideline was based on a review of evidence published through October 2012, as well as selected references published through April 2014. It revises the 2007 American College of Cardiology Foundation/AHA guideline for management of patients with unstable angina and non-ST-elevation myocardial infarction (NSTEMI), as well as the 2012 focused update. The new title of the guideline “emphasizes the pathophysiologic continuum of unstable angina and NSTEMI and their frequently indistinguishable clinical presentations,” the AHA and ACC said in a press release.

The guideline recommends that patients with suspected ACS should be risk-stratified according to the likelihood of ACS and adverse outcomes to decide on the need for hospitalization and assist in the selection of treatment options (class I recommendation; B evidence). Patients with suspected ACS and high-risk features such as continuing chest pain, severe dyspnea, syncope/presyncope, or palpitations should be referred immediately to the ED and transported by emergency medical services when available (class I recommendation; C evidence). Patients with less severe symptoms may be considered for referral to the ED, a chest pain unit, or another facility capable of performing adequate evaluation according to clinical circumstances (class IIb recommendation; C evidence).

Regarding discharge from the ED or chest pain unit, the guideline made these class IIa recommendations:

• It is reasonable to observe patients with symptoms consistent with ACS without objective evidence of myocardial ischemia (nonischemic initial electrocardiogram [ECG] and normal cardiac troponin) in a chest pain unit or telemetry unit with serial ECGs and cardiac troponin at 3- to 6-hour intervals (B evidence).
• It is reasonable for patients with possible ACS who have normal serial ECGs and cardiac troponins to have a treadmill ECG (A evidence), stress myocardial perfusion imaging, or stress echocardiography before discharge or within 72 hours after discharge (B evidence).
• In patients with possible ACS and a normal ECG, normal cardiac troponins, and no history of coronary artery disease (CAD), it is reasonable to initially perform (without serial ECGs and troponins) coronary CT angiography to assess coronary artery anatomy (A evidence) or rest myocardial perfusion imaging with a technetium-99m radiopharmaceutical to exclude myocardial ischemia (B evidence).
• It is reasonable to give low-risk patients who are referred for outpatient testing daily aspirin, short-acting nitroglycerin, and other medication if appropriate (e.g., beta-blockers), with instructions about activity level and clinician follow-up (C evidence).

After hospital admission, supplemental oxygen should be administered to patients with NSTE-ACS who have arterial oxygen saturation less than 90%, respiratory distress, or other high-risk features of hypoxemia, the guideline said (class I recommendation; C evidence). Nitroglycerin should be administered sublingually every 5 minutes for up to 3 doses for continuing ischemic pain, and need for IV nitroglycerin should then be assessed if not contraindicated (class I recommendation; C evidence); IV nitroglycerin should be administered for persistent ischemia, heart failure, or hypertension (class I recommendation; B evidence). Nitrates are contraindicated in patients who have recently taken a phosphodiesterase inhibitor (class III recommendation: harm; B evidence). Any NSAIDs besides aspirin should not be started and should be discontinued during hospitalization for NSTE-ACS because of an associated increased risk for major adverse cardiovascular events, the guideline said (class III recommendation: harm; B evidence).

During early hospitalization, oral beta-blockers should be initiated within the first 24 hours in patients without heart failure, low-output state, risk for cardiogenic shock, or other contraindication, the guideline said (class I recommendation; A evidence). It recommended sustained-release metoprolol succinate, carvedilol, or bisoprolol for beta-blocker therapy with concomitant NSTE-ACS, stabilized heart failure, and reduced systolic function (class I recommendation; C evidence). Initial therapy with nondihydropyridine calcium-channel blockers should be administered in patients with recurrent ischemia and contraindications to beta-blockers in the absence of left ventricular dysfunction, increased risk for cardiogenic shock, PR interval greater than 24 seconds, or second- or third-degree atrioventricular block without a cardiac pacemaker, the guideline said (class I recommendation; B evidence).

Oral nondihydropyridine calcium antagonists should be administered in patients with recurrent ischemia after use of beta-blockers and nitrates as long as contraindications aren't present (class I recommendation; C evidence); calcium-channel blockers are recommended for ischemic symptoms when beta-blockers are unsuccessful, contraindicated, or cause unacceptable side effects, although short-acting dihydropyridine calcium-channel antagonists should be avoided (class I recommendation; C evidence). High-intensity statins should be initiated or continued in patients with no contraindications (class I recommendation; A evidence).

The guideline also offered detailed recommendations on initial antiplatelet/anticoagulant therapy in patients with definite or likely NSTE-ACS and PCI, as well as a management algorithm comparing ischemia-guided strategy (formerly called “initial conservative management”) versus early invasive strategies. In an ischemia-guided strategy, the guideline recommended noninvasive stress testing in patients at low and intermediate risk who have had no ischemia at rest or with low-level activity for at least 12 to 24 hours (class I recommendation; B evidence). Pharmacological stress testing with imaging is recommended for patients with physical limitations that will not allow an adequate exercise stress test (class I recommendation; C evidence).

Aspirin should be continued indefinitely in NSTE-ACS patients, the guideline said, with a maintenance dose of 81 mg/d in patients who are treated with ticagrelor and 81 to 325 mg a day in all other patients (class I recommendation; A evidence). Either clopidogrel or ticagrelor should be continued for up to 12 months in patients with NSTE-ACS who have no contraindications and are treated according to an ischemia-guided strategy (class I recommendation; B evidence). Patients who receive a stent during PCI for NSTE-ACS should receive PSY₁₂ inhibitor therapy for at least 12 months (class I recommendation; B evidence).

Regarding secondary prevention, all patients with NSTE-ACS who are eligible should be referred to a comprehensive cardiovascular rehab program before hospital discharge or during their first outpatient visit (class I recommendation; B evidence). Patients should also receive education about appropriate cholesterol management, blood pressure, smoking cessation, and lifestyle management (class I recommendation; C evidence).

The guideline also includes recommendations for specific patient groups, including older patients, patients with heart failure and cardiogenic shock, patients with diabetes, patients who have had coronary artery bypass grafting, women, patients with chronic kidney disease, and others.

The full text of the guideline and an executive summary are available online.