Acute Coronary Syndrome: Current Treatment TIMOTHY L. SWITAJ, MD, U.S. Army Medical Department Center and School, Fort Sam Houston, Texas SCOTT R. CHRISTENSEN, MD, Martin Army Community Hospital Family Medicine Residency Program, Fort Benning, Georgia DEAN M. BREWER, DO, Guthrie Ambulatory Health Care Clinic, Fort Drum, New York Acute coronary syndrome continues to be a significant cause of morbidity and mortality in the United States. Family physicians need to identify and mitigate risk factors early, as well as recognize and respond to acute coronary syn- drome events quickly in any clinical setting. Diagnosis can be made based on patient history, symptoms, electrocardi- ography findings, and cardiac biomarkers, which delineate between ST elevation myocardial infarction and non–ST elevation acute coronary syndrome. Rapid reperfusion with primary percutaneous coronary intervention is the goal with either clinical presentation. Coupled with appropriate medical management, percutaneous coronary interven- tion can improve short- and long-term outcomes following myocardial infarction. If percutaneous coronary interven- tion cannot be performed rapidly, patients with ST elevation myocardial infarction can be treated with fibrinolytic therapy. Fibrinolysis is not recommended in patients with non–ST elevation acute coronary syndrome; therefore, these patients should be treated with medical management if they are at low risk of coronary events or if percutaneous coronary intervention cannot be performed. Post–myocardial infarction care should be closely coordinated with the patient’s cardiologist and based on a comprehensive secondary prevention strategy to prevent recurrence, morbidity, and mortality. (Am Fam Physician. 2017;95(4):232-240. Copyright © 2016 American Academy of Family Physicians.) CME This clinical content very 34 seconds, one American has of hospitalization and mortality in patients conforms to AAFP criteria a coronary event.1 It is important receiving appropriate treatment, ACS con- for continuing medical for primary care physicians to be tinues to be the most common cause of death education (CME). See 1 CME Quiz Questions on able to diagnose and manage acute in the United States. This article focuses page 220. Ecoronary syndrome (ACS), which com- on the treatment of ACS based on the 2013 Author disclosure: No rel- prises two clinical presentations: ST eleva- American College of Cardiology Foundation evant financial affiliations. tion myocardial infarction (STEMI) and (ACCF)/AHA guideline for the management non–ST elevation acute coronary syndrome of STEMI 4 and the 2014 ACC/AHA guide- (NSTE-ACS). The term non–ST elevation line for the management of NSTE-ACS.5 acute myocardial infarction (NSTEMI) is no longer used in the American College of Car- Primary Prevention diology/American Heart Association (ACC/ The ACC/AHA guidelines continue to AHA) guidelines as a broad category with emphasize the importance of primary pre- separate treatment guidelines. In lieu of this, vention of ACS by decreasing coronary artery ACS presentations not resulting in ST eleva- disease risk factors, including hypertension, tion are grouped together as NSTE-ACS, hypercholesterolemia, diabetes mellitus, and including NSTEMI and unstable angina. smoking.1 Family history of coronary artery As of 2010, more than 625,000 patients disease is also a risk factor. There are several were discharged from U.S. hospitals each risk calculators available, most notably the year with an ACS diagnosis.2 The GRACE Framingham risk score and, more recently, study found that approximately 30% of Pooled Cohort Equations for atherosclerotic patients with ACS had STEMI, whereas cardiovascular disease.6 The atheroscle- 70% had a type of NSTE-ACS.3 The aver- rotic cardiovascular disease risk estimator age age at first myocardial infarction (MI) is available online and in mobile app for- is 65 years in men and 72 years in women.2 mat at http://my.americanheart.org/cvrisk Although evidence shows decreased rates calculator and at http://www.cardiosource. 232Downloaded American from the Family American Physician Family Physician website at www.aafp.org/afp.www.aafp.org/afp Copyright © 2017 American AcademyVolume of Family 95, Physicians.Number 4 For ◆ theFebruary private, 15,noncom 2017- mercial use of one individual user of the website. All other rights reserved. Contact [email protected] for copyright questions and/or permission requests. Acute Coronary Syndrome BEST PRACTICES IN CARDIOLOGY: RECOMMENDATIONS FROM THE CHOOSING WISELY CAMPAIGN Recommendation Sponsoring organization org/en/Science-And-Quality/Practice- Do not test for myoglobin or creatine kinase- American Society for Clinical Guidelines-and-Quality-Standards/2013- MB in the diagnosis of acute myocardial Pathology infarction. Instead, use troponin I or T. Prevention-Guideline-Tools.aspx. However, this calculator has been criticized for overes- Source: For more information on the Choosing Wisely Campaign, see http:// timating the risk of cardiovascular disease in www.choosingwisely.org. For supporting citations and to search Choosing 7 Wisely recommendations relevant to primary care, see http://www.aafp.org/afp/ adults without diabetes. recommendations/search.htm. Family physicians should continue to edu- cate patients about the risk factors, clinical presentation, and symptoms of ACS. Older persons, per- should receive a loading dose of clopidogrel (300 mg sons with diabetes, women, and postoperative patients in persons younger than 75 years, or 75 mg in persons should be aware that they may have atypical symptoms 75 years and older) before treatment. Clopidogrel, 75 and presentation for ACS. At-risk patients should be reg- mg per day, should be continued in patients receiving ularly advised to seek medical care immediately if any fibrinolytic treatment for at least 14 days and up to one atypical symptoms occur.1 year. Glycoprotein IIb/IIIa inhibitors (such as tirofiban (Aggrastat), eptifibatide (Integrilin), and abciximab Initial Management [Reopro]) have shown benefit when used during PCI in At the individual level, patients should be advised to chew persons with STEMI and as an adjunct to PCI in persons a nonenteric coated aspirin (162 to 325 mg) at first rec- with NSTE-ACS; however, triple antiplatelet therapy has ognition of ACS symptoms, unless they have a history been associated with an increased risk of bleeding.1 of severe aspirin sensitivity.4 At the community level, Anticoagulation therapy should also be initiated with local areas should create and maintain emergency medi- either PCI or fibrinolytic therapy for the treatment of cal service systems that support STEMI care. Initial care STEMI. For patients undergoing PCI, unfractionated should include a full assessment of clinical symptoms heparin should be administered to maintain a therapeu- and coronary artery disease risk factors, as well as 12-lead tic activated clotting time level. Bivalirudin (Angiomax) electrocardiography. Electrocardiographic findings that is an option, even with previous use of unfractionated may reflect myocardial ischemia include changes in the heparin. Fondaparinux (Arixtra) should not be used as PR segment, QRS complex, and the ST segment.1 Part of sole anticoagulation therapy in patients undergoing PCI the initial assessment also involves obtaining cardiac bio- because of the risk of catheter thrombosis.4 For patients markers that include troponin (I or T). Primary percuta- receiving fibrinolytic therapy for STEMI, unfractionated neous coronary intervention (PCI) is the recommended heparin, enoxaparin (Lovenox), or fondaparinux can reperfusion method; therefore, all efforts should be made be used. Treatment should be given for a minimum of to transfer a patient with suspected STEMI to a PCI- 48 hours and up to eight days. capable hospital. If none is available within a 30-minute Additional acute treatment options include supple- travel time, medical management should occur in the mental oxygen, nitroglycerin, intravenous morphine, nearest emergency department. The goal of medical beta blockers, angiotensin-converting enzyme inhibi- management is to administer fibrinolytic therapy within tors or angiotensin receptor blockers, and statins. These 30 minutes of first medical contact.4 medications may be used for STEMI or NSTE-ACS, but with a few slight differences as outlined in Table 1.4,5 Medical Management There are limited data to support or refute the routine Table 1 summarizes the medications used to manage use of supplemental oxygen in the acute phase of man- ACS.4,5 Dual antiplatelet therapy is highly recommended agement.4 Oxygen supplementation may increase coro- in the treatment of STEMI to support primary PCI nary vascular resistance, although it may be appropriate and fibrinolytic treatment strategies. With either strat- in patients with oxygen saturation less than 90%. Mor- egy, aspirin therapy (162 to 325 mg per day) should be phine continues to be the medication of choice for pain started as soon as possible and continued indefinitely.4 relief in patients with STEMI; however, it should be used For patients undergoing primary PCI for STEMI, a P2Y12 in patients with NSTE-ACS only if anti-ischemic ther- receptor antagonist, such as clopidogrel (Plavix; 600 apy has been maximized and chest pain persists. Beta mg), should be administered as early as possible or at the blockers should be started within 24 hours in patients time of PCI, and a maintenance dosage of 75 mg per day with STEMI or NSTE-ACS