Page 13 - JSOM Fall 2021

Joint Trauma System Clinical Practice Guideline

Acute Coronary Syndrome (ACS)

14 May 2021

Overview
Deployed medical providers at all roles of care must be pre- electrocardiogram (ECG) can further assist in differentiating
pared to recognize and manage acute coronary syndrome the etiology of chest pain. 9,10
(ACS). Under optimal conditions, treatment is initiated with
medical therapy and may be followed by prompt coronary Diagnosis and management of ACS can be uniquely chal-
angiography and revascularization. Emergent percutaneous lenging in locations where PCI centers or treatment with fi-
coronary intervention (PCI) is not available in most deployed brinolytics are not available. PCI is recommended within 120
locations, however, and the time for such intervention is often minutes of first medical contact and is the preferred and most
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dependent on long-range evacuation. This CPG provides guid- common treatment for ACS in the US. However, if evacua-
ance on best management for ACS patients in the deployed tion is required, the delay to reach a PCI center may exceed
and resource-constrained environment. the recommended door-to-balloon time. Military physicians
located outside continental United States (OCONUS) may
therefore be required to treat ACS with fibrinolytics, which
Background
is not common in most US locations. Additionally, many di-
Coronary heart disease (CHD) is the leading cause of mor- agnostic tools helpful in evaluating chest pain, such as ECGs
tality in the US and worldwide. Cardiovascular health may and cardiac troponin assays, may not be available in many de-
1,2
in fact be worse for active duty servicemen when compared ployed locations. Refer to Appendix C for ACS management
to the civilian population. Additionally, cardiovascular dis- recommendations by role of care.
3
ease is the second most common chronic disease among ac-
tive duty Army personnel following arthritis. While clinical It is the responsibility of every medical provider to be prepared
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CHD typically presents at older ages, significant coronary ath- for initial management of ACS, to include understanding how
erosclerosis and myocardial infarction (MI) can manifest in to use teleconference services. Diagnosis and treatment of ACS
young adults and teenage patients. In a cross-sectional study should be guided by expert consultation. In addition, the ca-
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by Webber et al., coronary atherosclerosis was identified in pability to obtain and transmit an ECG and to provide cardiac
8.5% of the autopsies performed on US military personnel in first aid treatments with oxygen, nitroglycerin, and aspirin are
Operation Iraqi Freedom/Operation New Dawn (OIF/OND) key capabilities in initial stabilization and should be available
and Operation Enduring Freedom (OEF). In this study pop- to all deployed medical providers. Expanded capabilities for
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ulation, older age, lower educational level, higher body mass medical stabilization with antiplatelet agents, systemic anti-
index at military entrance, and prior diagnoses of dyslipid- coagulation, and fibrinolytic therapy should be available in
emia, hypertension, and obesity, were associated with a higher the evacuation chain within 24 hours and must be considered
prevalence of atherosclerosis. Additionally, MI/ACS was the during operational planning. Fibrinolytics are ideally given
most common medical/nonsurgical diagnosis for Critical Care within 12 hours of symptom onset; however, there may be a
Air Transport Team (CCATT) evacuations, representing 6.6% benefit up to 24 hours after symptom onset. 12,13
of 290 patients evacuated by CCATT during OIF/OEF. 7
Diagnosis
Acute coronary syndrome is typically a consequence of CHD
and refers to a spectrum of disease among patients experienc- ACS is a clinical syndrome that includes MI and unstable
ing, or suspected of experiencing, myocardial ischemia. ACS angina. An MI can present as either a STEMI or NSTEMI.
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is further divided into three subgroups: 1) ST-elevation MI A STEMI typically occurs as a result of plaque rupture and
(STEMI), 2) non–ST-elevation MI (NSTEMI), and 3) unstable subsequent thrombosis of a coronary artery that leads to in-
angina. farction and subsequent ECG changes. An NSTEMI does not
have the ECG changes seen in STEMI but can also occur sec-
When evaluating patients with chest pain concerning ACS, it ondary to plaque rupture (type 1 NSTEMI) or to inadequate
is important to consider other life-threatening causes of chest blood flow to meet the metabolic demands of the myocardium
pain such as pulmonary emboli, pneumonia, aortic dissection, in conditions like sepsis, pulmonary embolism, or coronary
pneumothorax, esophageal rupture, and myocarditis as they vasospasm (type 2 NSTEMI). In either case, both STEMI and
are managed differently. A thorough history and physical NSTEMI will result in an elevated troponin. Unstable angina
exam may be helpful in guiding the deployed provider towards is characterized by new-onset chest pain, pain lasting greater
a presumptive diagnosis. When available, imaging, labs, and than 20 minutes, or pain at rest or with minimal exertion.

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