Chapter 53: Management of ST-Elevation Myocardial Infarction

A nurse is giving aspirin to a patient during acute management of STEMI. The patient asks why a chewable tablet is given. Which response by the nurse is correct? a. "Aspirin is absorbed more quickly when it is chewed." b. "Chewing aspirin prevents it from being metabolized by the liver." c. "Chewing aspirin prevents stomach irritation." d. "More of the drug is absorbed when aspirin is chewed."

ANS: A Aspirin should be chewed to allow rapid absorption across the buccal mucosa. Chewing aspirin does not affect hepatic metabolism, stomach irritation, or the amount absorbed.

A patient arrives in the emergency department complaining of chest pain that has lasted longer than 1 hour and is unrelieved by nitroglycerin. The patient's electrocardiogram reveals elevation of the ST segment. Initial cardiac troponin levels are negative. The patient is receiving oxygen via nasal cannula. Which drug should be given immediately? a. Aspirin 325 mg chewable b. Beta blocker given IV c. Ibuprofen 400 mg orally d. Morphine intravenously

ANS: A This patient shows signs of acute ST-elevation myocardial infarction (STEMI). Because cardiac troponin levels usually are not detectable until 2 to 4 hours after the onset of symptoms, treatment should begin as symptoms evolve. Chewable aspirin (ASA) should be given immediately to suppress platelet aggregation and produce an antithrombotic effect. Beta blockers are indicated but do not have to be given immediately. Ibuprofen is contraindicated. Morphine is indicated for pain management and should be administered after aspirin has been given.

Patients with a history of myocardial infarction should take which medications indefinitely? (Select all that apply.) a. ACE inhibitors b. Alteplase c. Aspirin d. Beta blockers e. Clopidogrel

ANS: A, C, D Patients who have had an MI should take ACE inhibitors, ASA, and beta blockers indefinitely to prevent recurrence and to minimize continuing cardiac remodeling. Alteplase is given during acute management, and clopidogrel is used during acute management and as an adjunct to reperfusion therapy.

A patient is admitted to the coronary care unit from the emergency department after initial management of STEMI. A primary percutaneous coronary intervention has been performed. The nurse notes an initial heart rate of 56 beats per minute and a blood pressure of 120/80 mm Hg. The patient has a history of stroke and a previous myocardial infarction. Which order will the nurse question? a. Aspirin b. Beta blocker c. Clopidogrel d. Heparin

ANS: B A beta blocker would be contraindicated in this patient, because it slows the heart, and this patient is already bradycardic. Aspirin, clopidogrel, and heparin are recommended in patients who have had a primary PCI.

A patient who is receiving reperfusion therapy has a history of heparin-induced thrombosis (HIT). The patient has a creatinine clearance of 28 mL/min. In addition to the fibrinolytic agent, which medication will the nurse expect to administer to this patient? a. Aspirin b. Bivalirudin [Angiomax] c. Clopidogrel [Plavix] d. Fondaparinux [Arixtra]

ANS: B Patients receiving a fibrinolytic medication will also need an anticoagulant to reduce the risk of thrombosis. This patient cannot receive heparin because of the history of HIT, so he or she will need either bivalirudin or fondaparinux. Bivalirudin may be used at reduced doses in patients with a creatinine clearance less than 30 mL/min, but fondaparinux is contraindicated in such patients. Antiplatelet drugs such as aspirin or clopidogrel are not used for this purpose.

A patient has undergone a primary percutaneous coronary intervention with a stent placement. The provider has ordered a daily dose of 81 mg of aspirin and clopidogrel. The patient asks the nurse how long the medications must be taken. What will the nurse tell this patient about the medication regimen? a. This drug regimen will continue indefinitely. b. The clopidogrel will be discontinued in one year and the aspirin will be given indefinitely. c. The aspirin will be discontinued in one year and the clopidogrel will be given indefinitely. d. Both drugs will be discontinued in one year.

ANS: B Patients who have undergone PCI with a stent will take ASA indefinitely along with an antiplatelet drug for one year. The clopidogrel will be discontinued in one year, but the aspirin will be given indefinitely.

A patient has undergone a PCI, and the provider orders clopidogrel to be given for 12 months, along with an ACE inhibitor and heparin. What will the nurse do? a. Question the need for heparin. b. Request an order for a beta blocker. c. Request an order for aspirin. d. Suggest ordering clopidogrel for 14 days.

ANS: C Patients who have undergone a PCI should receive heparin, ASA, and a fibrinolytic; therefore, this patient needs ASA added to the drug regimen. Heparin should be given before, during, and for at least 48 to 72 hours after the procedure. Beta blockers are not necessarily indicated. Clopidogrel should be given at least 12 months after the procedure.

A nurse is evaluating a patient admitted to the emergency department with an evolving STEMI for possible administration of thrombolytic therapy. Which information, identified during history taking, would contraindicate this type of therapy? a. The patient just completed her last menstrual cycle. b. The patient states that the chest pain started 1 hour ago. c. The patient has a history of a small cerebral aneurysm. d. The patient has hypertension that is well controlled by diuretic therapy.

ANS: C Patients with a history of CVA should not receive fibrinolytic therapy. This patient has had a known cerebral aneurysm. Active internal bleeding is a contraindication for thrombolysis except for menses, but the patient has indicated she has completed her last cycle. Fibrinolytic therapy should be administered for chest pain that has been present for no longer than 12 hours. Poorly controlled or severe hypertension is a relative contraindication. Thrombolytics can be administered with caution.

A nurse is discussing fibrinolytic therapy for the acute phase of STEMI management with a group of nursing students. Which statement by a student indicates understanding of this therapy? a. "Fibrinolytics are effective when the first dose is given up to 24 hours after symptom onset." b. "Fibrinolytics should be given once cardiac troponins reveal the presence of STEMI." c. "Fibrinolytics should be used with caution in patients with a history of cerebrovascular accident." d. "Patients should receive either an anticoagulant or an antiplatelet agent with a fibrinolytic drug."

ANS: C Patients with a history of cerebrovascular accident (CVA) should not receive fibrinolytic agents because of the increased risk of intracranial hemorrhage. Fibrinolytics are most effective when given within 30 minutes of arrival in the emergency department. Because cardiac troponins are not detectable until 2 to 4 hours after the onset of symptoms, fibrinolytics should be administered before these laboratory values are available. Patients receiving fibrinolytics should receive both an anticoagulant and an antiplatelet drug.

A patient in the emergency department has severe chest pain. The nurse administers morphine intravenously. The patient asks the nurse why morphine is given. Which response by the nurse is correct? a. "Morphine helps by reducing anxiety and relieving pain." b. "Morphine helps by reducing pain and dissolving clots." c. "Morphine helps by relieving pain and lowering blood pressure." d. "Morphine helps by relieving pain and reducing the cardiac oxygen demand."

ANS: D IV morphine is the treatment of choice for STEMI-associated pain. Besides relieving pain, it promotes vasodilation and reduces cardiac preload, which lowers the cardiac oxygen demand. It does not reduce anxiety, dissolve clots, or lower blood pressure.

A patient diagnosed with STEMI is about to undergo a primary percutaneous coronary intervention (PCI). Which combination of pharmacotherapeutic agents will be given to augment this procedure? a. Beta blocker and nitroglycerin b. Abciximab and a fibrinolytic drug c. Angiotensin-converting enzyme (ACE) inhibitor and aspirin d. Heparin, aspirin, and clopidogrel

ANS: D Patients undergoing a primary PCI should receive heparin intravenously combined with aspirin and either clopidogrel or prasugrel. Abciximab and fibrinolytic drugs are not indicated. Beta blockers and nitroglycerin do not prevent thromboses. ACE inhibitors do not prevent thromboses

A patient who is recovering from a STEMI 3 months prior is in the clinic for a follow-up evaluation. The patient is taking 81 mg of aspirin, a beta blocker, and an ACE inhibitor daily and uses nitroglycerine as needed for angina. The patient's BMI is 24.5 kg/m2, and serum LDL is 150 mg/dL. The patient has a blood pressure of 135/80 mm Hg. What will the nurse expect the provider to order for this patient? a. An antihypertensive medication b. Counseling about a weight loss diet c. Discontinuing the ACE inhibitor d. High-dose statin therapy

ANS: D To help prevent recurrence of MI in patients post-STEMI, a high-dose statin should be given to patients with elevated cholesterol. This patient's blood pressure and BMI are normal, so antihypertensives and a weight loss diet are not recommended. The three drugs should be continued indefinitely.