A 56-year-old man is brought to the emergency department due to chest pain. An hour ago, he woke up with severe, burning, retrosternal chest pain accompanied by sweating and left arm numbness. The patient's symptoms subsided with aspirin and sublingual nitroglycerin administered by the paramedics; he currently rates the pain as 4 on a scale of 0-10. He has had no nausea, vomiting, or abdominal discomfort. The patient has a history of gastroesophageal reflux disease and diet-controlled diabetes mellitus. He has a 30-pack-year history. Temperature is 37.3 (99 F), blood pressure is 150/90 mm Hg on the right arm and 145/88 mm Hg on the left arm, and pulse is 95/min and regular. The lungs are clear on auscultation, and heart sounds are normal with no murmur or gallop. ECG shows normal sinus rhythm with T-wave inversions in leads V1 through V4. The troponin level is normal. Which of the following is the most appropriate next step in management of this patient?
Acute management of acute coronary syndrome (STEMI, NSTEMI, or unstable angina) | |
Nitrates |
|
Beta blocker |
|
Antiplatelet therapy |
|
Anticoagulation |
|
Statin therapy |
|
Coronary reperfusion | STEMI
NSTEMI or unstable angina
|
*In patients with NSTEMI or unstable angina, P2Y12 inhibitor therapy is often held until after coronary angiography in case the atherosclerotic coronary anatomy indicates the need for coronary artery bypass grafting. NSTEMI = non–ST-segment elevation myocardial infarction; PCI = percutaneous coronary intervention; RV = right ventricular; STEMI = ST-segment elevation myocardial infarction. | |
This patient's clinical presentation—sudden onset of chest discomfort with left arm numbness, diaphoresis, and T-wave inversions in the anterior precordial leads—is consistent with acute coronary syndrome (ACS) due to unstable angina (UA) or non–ST-segment elevation myocardial infarction (NSTEMI). A significant troponin elevation within 6-12 hours differentiates NSTEMI from UA, but acute management of the conditions is the same. The goals include relief of ischemic pain, assessment and maintenance of hemodynamic stability, and prevention of recurrent ischemia and thrombosis.
The following pharmacologic agents are used:
Antiplatelet agents (eg, aspirin plus clopidogrel, ticagrelor, or prasugrel) and anticoagulant therapy (eg, unfractionated heparin, enoxaparin, fondaparinux, bivalirudin) to prevent intracoronary thrombus propagation and abrupt vessel occlusion
Beta blockers (eg, metoprolol, atenolol) to reduce myocardial oxygen demand and the risk of ventricular arrhythmia
Nitrates as needed to reduce myocardial oxygen demand, relieve ischemic pain, and reduce preload
High-intensity statins (eg, atorvastatin, rosuvastatin) to stabilize atherosclerotic plaque and lower the risk of recurrent ACS
(Choice A) Exercise stress testing is used to evaluate for coronary artery disease in patients with symptoms consistent with stable angina (eg, chest pain with exertion that resolves with rest) or after a period of medical stabilization of ACS. However, subjecting a patient with evolving ACS to a stress test could cause extension of the infarcted area or provoke a life-threatening arrhythmia. This patient's clinical presentation is highly consistent with ACS, so stress testing is not appropriate until he is stabilized.
(Choice B) Intravenous alteplase (tissue plasminogen activator) is a fibrinolytic agent indicated for the treatment of ST-segment elevation myocardial infarction (STEMI) when timely primary percutaneous revascularization is unavailable. Fibrinolytic therapy is not indicated for ACS due to UA or NSTEMI.
(Choice D) Prophylactic administration of lidocaine or any other antiarrhythmic therapy (other than beta blockers) is not recommended in ACS. However, serum potassium and magnesium should be maintained at normal levels to help prevent arrhythmias.
(Choice E) Oral proton pump inhibitors are used to treat gastroesophageal reflux disease. The chest pain of MI can be similar to that of gastroesophageal reflux disease; however, this patient's ECG findings suggestive of ischemia (eg, anterior precordial T-wave inversion) make ACS more likely.
Educational objective:
Acute coronary syndrome (ACS) due to unstable angina or non–ST-segment elevation myocardial infarction is managed with antiplatelet and anticoagulant agents, beta blockers, nitrates as needed, and high-intensity statins. Fibrinolytic therapy is not used in patients with non–ST-segment elevation ACS.