Acute coronary syndromes

This chapter will review the pharmacologic management of acute coronary syndromes (ACS) according to the 2013 American College of Cardiology Foundation/American Heart Association (AHA) ST-Elevation Myocardial Infarction (STEMI) and 2014 AHA/American College of Cardiology Non-ST-Elevation Acute Coronary Syndromes (NSTE-ACS) guidelines.

Clinical signs and symptoms of ACS ( fig. 1.1 )

Causes of troponin elevations ( box 1.1 )

Box 1.1

Causes of Troponin Elevations

Acute decompensated heart failure	Early post–cardiac surgery
Acute MI	Heart transplantation
Acute pulmonary embolism	Myocarditis
Aortic stenosis	Pericarditis
Cardiac amyloidosis	Post-PCI
Cardiotoxic chemotherapy	Rhabdomyolysis
Chest compressions	Sepsis
Chest wall trauma	Severe strenuous exercise
Chronic heart failure	Tachyarrhythmia
Direct current cardioversion/defibrillation	Type A dissection

MI , Myocardial infarction; PCI , Percutaneous coronary intervention

Acute management of ACS

Goals of care ( box 1.2 )

Box 1.2

Goals of Care

Data from O’Gara PT, Kushner FG, Ascheim DD, et al. ACCF/AHA guideline for the management of ST-elevation myocardial infarction: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Circulation. 2013;127:e362–e425; Amsterdam EA, Wenger NK, Brindis RG, et al. AHA/ACC guideline for the management of patients with non–ST-elevation acute coronary syndromes: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation . 2014;130:2354–2394.

STEMI: REPERFUSION THERAPY	NSTE-ACS: PREVENT TOTAL OCCLUSION OF THE VESSEL
Primary PCI recommended if possible within 90 min of presentation If primary PCI impossible within 120 min of medical contact, thrombolytic recommended within 30 min of presentation unless contraindicated Surgical revascularization may be indicated	Revascularization within 24–72 h vs. medical management depending on risk stratification, symptom resolution, and indicators of ongoing myocardial damage/ischemia

NSTE-ACS , Non-ST-elevation acute coronary syndromes; PCI , Percutaneous coronary intervention; STEMI , ST-elevation myocardial infarction

Initial interventions on presentation of ACS ( box 1.3 )

Box 1.3

Initial Interventions on Presentation of ACS

Data from Amsterdam EA, Wenger NK, Brindis RG, et al. 2014 AHA/ACC guideline for the management of patients with non–ST-elevation acute coronary syndromes: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation . 2014;130:2354–2394.

Morphine	2–4 mg IV q5min prn chest pain Provides analgesia and decreases pain-induced sympathetic tone Morphine may induce vasodilation and preload reduction
Oxygen	2–4 L/min by nasal cannula or face mask if hypoxemia (SaO ₂<90%), HF, or dyspnea Use cautiously because it may promote coronary vasoconstriction and generate toxic O ²metabolites
Aspirin	162–325 mg (non-EC) chewed and swallowed immediately, then 81 mg (EC) daily Inhibit platelet activation
Nitroglycerin (NTG)	Facilitate coronary vasodilation NTG 0.4 mg sublingually or spray q5min ×3. If continuous ischemic pain, HF, or htn, IV NTG 10 mcg/min increased by 5 mcg/min q5min to desired effect (NTE 200 mcg/min) Avoid NTG if: • SBP <90 mm Hg or SBP ≤30 mm Hg below baseline • Severe bradycardia with HR ≤50 • HR ≥100 in the absence of symptomatic HF, or RV infarction • Oral phosphodiesterase inhibitor within the past 24–48 h
β-Blockers	Metoprolol 5 mg IV q5min up to ×3 then 25–50 mg PO q6–12h, transitioned to metoprolol tartrate BID or metoprolol succinate daily Decreases risk of ventricular arrhythmias and sudden cardiac death post-MI Improves oxygen flow through the coronary arteries Initiate within first 24 h of ACS except for: • Signs of HF or low-output state • Increased risk of cardiogenic shock (SBP <120, HR >110 or <60, age >70) • Other CI to β-blockade (i.e., active asthma, reactive airway disease, heart block)
Acronym MONA ± β-Blockers	M orphine O xygen N itroglycerin A spirin β-Blocker

ACS , Acute coronary syndromes; BID , Twice daily; CI , Contraindication; EC , Enteric coated; HF , Heart failure; HR , Heart rate; htn , Hypertension; MI , Myocardial infarction; NTE , Not to exceed; PO , Orally; RV , Right ventricular; SBP , Systolic blood pressure