Chapter 37 Coronary Artery Disease and Acute Coronary Syndrome Answer Keys for Questions • Rationales for Bridge to NCLEX Examination Questions 1. Correct answers: b, c, d Rationale: Atherosclerosis is the major cause of coronary artery disease (CAD). It is characterized by a focal deposit of cholesterol and lipids, primarily within the intimal wall of the artery. The endothelial lining of the coronary arteries becomes inflamed from the presence of unstable plaques and the oxidation of low-density lipoprotein (LDL) cholesterol. Fibrous plaque causes progressive changes in the endothelium of the arterial wall. The result is a narrowing of the vessel lumen and a reduction in blood flow to the myocardial tissue. 2. Correct answer: b Rationale: Risk factors for coronary artery disease include high serum levels of lipids, high BP, tobacco use, physical inactivity, obesity, diabetes, metabolic syndrome, certain psychologic states, and high homocysteine levels. Weight lifting is not a cardioprotective exercise. An example of health-promoting regular physical activity is brisk walking (3 to 4 miles/hr) for at least 30 minutes 5 or more times each week. 3. Correct answer: b Rationale: Chronic stable angina is chest pain that occurs intermittently over a long period with the same pattern of onset, duration, and intensity of symptoms. The chest pain is relieved by rest or by rest and medication (e.g., nitroglycerin). The ischemia is transient and does not cause myocardial damage. Copyright © 2023 by Elsevier, Inc. All rights reserved. 4. Correct answer: b Rationale: Acute pericarditis is inflammation of the visceral and/or parietal pericardium. It often occurs 2 to 3 days after an acute myocardial infarction. Chest pain may vary from mild to severe. It is worsened by inspiration, coughing, and movement of the upper body. Sitting in a forward position often relieves the pain. The pain is usually different from pain associated with a myocardial infarction and is treated with different medications. Assessment of the patient with pericarditis may reveal a friction rub over the pericardium. 5. Correct answers: a, b, e Rationale: When a patient presents with suspected ACS, antiplatelet therapy, IV NTG, and atorvastatin are drug treatments of choice. For patients with UA and NSTEMI, heparin (UH or LMWH) is recommended to prevent microemboli from forming and causing further chest pain. DAPT (e.g., aspirin and clopidogrel or ticagrelor [Brilinta]) also is recommended for NSTEMI patients (with or without a stent). Thrombolytic therapy and antibiotics are not indicated for NSTEMI. 6. Correct answer: c Rationale: Physical activity should be regular, rhythmic, and repetitive, with the use of large muscles to build up endurance (e.g., walking, cycling, swimming, rowing). Physical activity sessions should be at least 30 minutes long. Teach the patient to begin slowly at personal tolerance (perhaps only 5 to 10 minutes) and build up to 30 minutes. 7. Correct answer: c Rationale: Left ventricular dysfunction (ejection fraction less than 30%) and ventricular dysrhythmias after myocardial infarction are the strongest predictors of sudden cardiac death Copyright © 2023 by Elsevier, Inc. All rights reserved. (SCD). • Answer Guidelines for Case Study in the text. 1. Explain the pathogenesis of CAD. What risk factors contribute to its development? What risk factors were present in D.M.’s life? The pathogenesis of coronary artery disease (CAD) develops over many years and involves the development of atherosclerosis of the coronary arteries. The development of atherosclerosis occurs in 3 stages: (1) fatty streak, in which streaks of fat develop within the smooth muscle cells of the arteries; (2) raised fibrous plaque, in which endothelial injury results in the formation of a plaque composed of fatty lesions that are covered with collagen tissue, elastic fibers, and smooth muscle cells filled with fat; and (3) complicated lesion, in which the plaque consists of a core of lipid materials within an area of dead tissue that continues to grow by incorporating lipids, thrombi, damaged tissue, and calcium. The result is rigidity and hardening of the artery with total or partial occlusion of the artery by the lesion. Risk factors that contribute to atherosclerosis and coronary artery disease include both nonmodifiable and modifiable factors. Those factors that are not modifiable include age, gender, ethnicity, genetic predisposition, and family history of heart disease. Those factors that are modifiable include high serum lipids, hypertension, tobacco use, obesity, physical inactivity, diabetes, and stressful lifestyle. Risk factors present in D.M.’s life include a history of CAD (chronic stable angina), hypertension, obesity, physical inactivity, stress, and high serum total cholesterol and Hb A1C. 2. Which coronary artery(ies) is/are most likely occluded in D.M.’s coronary circulation? An inferolateral wall myocardial infarction (MI) is usually the result of blockages in the right coronary and circumflex artery. Copyright © 2023 by Elsevier, Inc. All rights reserved. 3. Explain the significance of the results of the laboratory tests and the 12-lead ECG findings. The high troponin level shows that myocardial cellular death has occurred. The high cholesterol level and Hb A1C are evidence of his increased risk for CAD. The premature ventricular contractions found on the ECG are common findings after MI and may occur because of myocardial ischemia, electrolyte imbalances, or SNS stimulation. The ST elevation in leads II, III, and aVF; V5, V6 represent myocardial death in the inferior and lower lateral wall of the left ventricle. 4. Give a rationale for each treatment measure ordered for D.M. • Oxygen is applied to ensure the adequacy of oxygen supply to the heart muscle. • Continuous ECG monitoring allows for a constant readout of the heart rate and rhythm. It also allows for detection of dysrhythmias (e.g., atrial fibrillation, premature ventricular contractions, ventricular tachycardia) and return of ST segment elevations to baseline. • Aspirin is used as an antithrombotic agent to prevent platelet aggregation around thrombi and atherosclerotic lesions. • Eptifibatide (Integrilin) is a glycoprotein IIb/IIIa inhibitor (antiplatelet agent) used to prevent platelet aggregation around thrombi and atherosclerotic lesions. It should not delay D.M. getting to the cardiac catheterization laboratory. • Weight-based IV heparin is an anticoagulant used to prevent further extension of the existing thrombi or new clot formation. It only would be used if D.M. does not go directly to the cardiac catheterization laboratory. Copyright © 2023 by Elsevier, Inc. All rights reserved. • IV nitroglycerin decreases preload and afterload while increasing the myocardial oxygen supply. IV nitroglycerin is usually titrated to relieve pain. Because hypotension is a common side effect, BP is closely monitored during this time, and parameters should be established. • IV morphine is a vasodilator and decreases cardiac workload by lowering myocardial oxygen consumption, reducing contractility, and decreasing BP and HR. In addition, morphine can help reduce pain, anxiety, and fear. • Vital signs and pulse oximetry are monitored frequently (according to agency policy) during the acute phase of an MI to evaluate the patient’s response to treatments and detect the development of complications (e.g., heart failure, cardiogenic shock). • PCI is the first line of treatment for patients with confirmed STEMI (i.e., definitive ECG changes of ST elevation and/or positive cardiac biomarkers). The goal is to open the affected artery within 90 minutes of arrival to a facility with an interventional cardiac catheterization lab. • In this situation, D.M. will have a cardiac catheterization within 90 minutes of arrival to find and assess the severity of the blockage(s), determine the presence of collateral circulation, and evaluate left ventricular function. With actual visualization of the coronary artery system and left ventricular function, treatment modalities most beneficial to the patient are selected. Usually PCI with the placement of a stent(s) is performed on the artery responsible for the infarction. If other arteries have significant blockage, they are stented later. 5. What are the priority nursing interventions for D.M. before PCI? Immediately after PCI? • Perform all required activities needed to prepare patient for rapid and safe transfer to the cardiac catheterization laboratory (e.g., IV access, blood work, 12-lead ECG). Copyright © 2023 by Elsevier, Inc. All rights reserved. • Explain all interventions to patient, including preparations for transfer to the cardiac catheterization lab. • Give drugs to relieve pain as ordered and monitor their effectiveness. • Titrate supplemental oxygen as ordered. • Monitor continuous ECG. • Frequently monitor vital signs, including pulse oximetry. • Assess heart and breath sounds. • Provide support to help him deal with anxiety and other emotions related to his MI. • Offer to bring caregiver(s) to bedside and explain all activities. Immediately after his PCI? • Monitor for signs of recurrent angina. • Monitor vital signs, including pulse oximetry. • Assess heart and breath sounds. • Monitor continuous ECG. • Monitor catheter insertion site for signs of bleeding. • Perform neurovascular assessment of involved extremity. • Maintain bed rest per agency policy. 6. Identify activities that can be delegated to unlicensed assistive personnel (UAP). Activities that can be delegated to UAP: • Vital signs, including pulse oximetry • Provide oral hygiene as needed • Assist with getting out of bed and toileting Copyright © 2023 by Elsevier, Inc. All rights reserved. • Assist with feeding, as ordered • Obtain capillary blood glucose level according to agency policy 7. What outcomes would show that the interdisciplinary care was successful? Transfer of D.M. to the cardiac catheterization laboratory within 90 minutes. Successful placement of stents in blocked arteries. No bleeding from the catheter insertion site or any other complication after PCI. Resolution of chest pain. Stable vital signs and heart rhythm. Patient requesting information about lifestyle changes. Copyright © 2023 by Elsevier, Inc. All rights reserved.
