Community and Prehospital Strategies for Managing Patients with Acute Coronary Syndromes

Joseph P. Ornato

Just as in cardiac arrest, a STEMI ‘chain of survival’ metaphor can be used to emphasize the need for rapid (1) symptom recognition and a call for help, (2) emergency medical services (EMS) evaluation and treatment, (3) emergency department (ED) evaluation and treatment, and (4) reperfusion therapy.¹

Early symptom recognition activates a STEMI Chain of Survival providing access to optimized time-sensitive care for patients with chest discomfort and possible ACS.
Prehospital electrocardiograms identify patients with STEMI for rapid reperfusion and appropriate destination hospital selection.
STEMI systems of care, provide rapid reperfusion for STEMI patients and optimize resource utilization for possible ACS patients.

Introduction

The 2005 American Heart Association (AHA) Guidelines for Cardiopulmonary Resuscitation (CPR) and Emergency Cardiovascular Care (ECC) state that half of all patients who die from acute myocardial infarction (AMI) will do so before reaching the hospital, with most deaths due to ventricular tachycardia (VT) or fibrillation (VF) in the first 3 to 4 hours after onset of symptoms.² The guidelines encourage communities to “develop programs to respond to out-of-hospital cardiac arrest that include prompt recognition of symptoms of acute coronary syndromes (ACS), early activation of the emergency medical services (EMS) system, and, if needed, early CPR and early access to an automated external defibrillator (AED) through community AED programs.”²

Effective interventions exist for the majority of ACS patients, but these interventions are extremely time-sensitive, particularly for those with acute ST-segment-elevation myocardial infarction (STEMI). Just as in cardiac arrest, a STEMI “chain of survival” metaphor (Fig. 4-1) can be used to emphasize the need for rapid (1) symptom recognition and a call for help; (2) EMS evaluation and treatment; (3) emergency department (ED) evaluation and treatment; and (4) reperfusion therapy.¹ This chapter focuses on community and prehospital evidence-based guideline management strategies that can be used to reduce ACS morbidity and mortality.³^,⁴^,⁵^,⁶

Symptom Recognition

Many laypersons do not know or recognize the symptoms of cardiac ischemia or infarction (i.e., a “heart attack”), which often delays seeking medical evaluation and care. The longest interval from STEMI symptom onset to definitive treatment is usually due to delay in patient symptom recognition and arrival at the point of care.⁷ Failure to recognize symptoms as being caused by a heart attack can be due to inadequate knowledge of AMI symptoms, maladaptive coping strategies, or misattribution of the symptoms to another, noncardiac cause.⁸^,⁹^,¹⁰ Common reasons why STEMI patients delay seeking emergency medical attention are listed in Table 4-1.⁵

Figure 4-1 • The STEMI “Chain of Survival”: (1) symptom recognition and a call for help; (2) EMS evaluation and treatment; (3) emergency department (ED) evaluation and treatment; and (4) rapid reperfusion therapy.¹

The longest interval from STEMI symptom onset to definitive treatment is usually due to delay in patient symptom recognition and health-seeking behavior.

Goff et al.¹¹ conducted random-digit-dialed telephone surveys of the 1,294 adults in 20 U.S. cities involved in the National Institutes of Health (NIH)–sponsored Rapid Early Action for Coronary Treatment (REACT) trial to determine how frequently laypersons could identify common symptoms of a heart attack (chest discomfort, arm or shoulder pain or discomfort, jaw or neck pain, back pain, shortness of breath, nausea or vomiting, sweating, light-headedness, and weakness). Chest discomfort was reported as a symptom by 89.7% of respondents and was thought to be the most important symptom by 56.6%. Knowledge of arm pain or numbness (67.3%), shortness of breath (50.8%), sweating (21.3%), and other heart attack symptoms was less common. In a multivariable-adjusted model,
significantly higher mean numbers of correct symptoms were reported by non-Hispanic whites than by other racial or ethnic groups, by middle-aged persons than by older and younger persons, by persons with higher socioeconomic status than by those with lower, and by persons with versus those without previous heart attack experience. The authors concluded that, although the public’s knowledge of chest discomfort as an important heart attack symptom is relatively high, knowledge of the complex constellation of heart attack symptoms is deficient in the U.S. population, especially in low-socioeconomic and racial or ethnic minority groups.

Table 4-1 • Reasons Why STEMI Patients Delay in Seeking Emergency Medical Attention

Expected a dramatic presentation
Thought symptoms were not serious/would go away
Took a “wait and see” approach to the initial symptoms that included self-evaluation, self-treatment, and reassessment until “certain”
Tended to attribute symptoms to other chronic conditions (e.g., arthritis, muscle strain) or common illnesses (e.g., influenza)
Lacked awareness of the benefits of rapid action, reperfusion treatment, or of the importance of calling EMS/911 for AMI symptoms
Expressed fear of embarrassment if symptoms turned out to be a false alarm; reluctant to “bother” physicians or EMS unless “really sick”; needed “permission” from others such as health care providers, spouses, family to take rapid action
Few ever discussed symptoms, responses, or actions for a heart attack in advance with family or providers
Stereotypes of who is at risk for a heart attack
Not perceived at risk if:
- Young and healthy
- A woman
- Under a doctor’s care or making lifestyle changes (especially men with risk factors)

From Antman EM, Anbe DT, Armstrong PW, et al. ACC/AHA guidelines for the management of patients with ST-elevation myocardial infarction—executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 1999 Guidelines for the Management of Patients With Acute Myocardial Infarction). Circulation 2004;110(5):588–636, with permission.

Atypical Symptoms

Atypical symptom presentations for ACS, including STEMI, are more commonly seen in elderly, female, and diabetic patients.¹²^,¹³^,¹⁴^,¹⁵^,¹⁶^,¹⁷ A surprisingly large percentage of patients presenting to the hospital proven subsequently to have AMI do not have chest discomfort. Canto et al.¹⁸ found that 142,445 of 434,877 patients (33%) with confirmed AMI in the National Registry of Myocardial Infarction-2 did not have chest discomfort on presentation to the hospital. This group of AMI patients was, on average, 7 years older than those with chest discomfort (74.2 vs. 66.9 years) and included a higher proportion of women (49.0% vs. 38.0%) and patients with diabetes mellitus (32.6% vs. 25.4%), or prior heart failure (26.4% vs. 12.3%). AMI patients without chest discomfort had a longer delay before hospital presentation (mean, 7.9 vs. 5.3 hours), were less likely to be diagnosed as having confirmed AMI at the time of admission (22.2% vs. 50.3%) and were less likely to receive fibrinolysis or a primary percutaneous intervention (PCI) (25.3% vs. 74.0%), aspirin (ASA; 60.4% vs. 84.5%), beta-blockers (28.0% vs. 48.0%), or heparin (53.4% vs. 83.2%) compared with those with chest discomfort. AMI patients without chest discomfort had a 23.3% in-hospital mortality rate, compared with 9.3% among patients with chest pain (adjusted odds ratio for mortality, 2.21 [95% CI, 2.17–2.26]). The authors concluded that patients without chest pain on hospital presentation represent a large segment of the AMI population and are at increased risk for delays in seeking medical attention, less aggressive treatments, and in-hospital mortality.

Atypical symptom presentations for ACS, including STEMI, are more commonly seen in elderly, female, and diabetic patients. A surprisingly large percentage of patients presenting to the hospital proven subsequently to have AMI do not have chest discomfort.

Prodromal unstable angina symptoms are present in roughly half of AMI patients and are associated with a more favorable prognosis, probably by ischemic preconditioning of the myocardium.¹⁹^,²⁰^,²¹^,²² Prodromal unstable angina was a strong predictor of a smaller infarct size as judged by creatine kinase release (P = 0.017) and was associated with an increased odds ratio (3.83; 95% CI, 1.27–11.47) for 5-year survival in the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-I) study.²¹

Women

Women are particularly likely to have prodromal symptoms prior to AMI. In a recent study, 489 of 515 (95%) of women diagnosed with AMI treated at five different hospitals reported prodromal symptoms in the weeks prior to their infarction.²³ The most frequent prodromal symptoms experienced >1 month before AMI were unusual fatigue (70.7%), sleep disturbance (47.8%), and shortness of breath (42.1%). Only 29.7% reported chest discomfort. The most frequent acute symptoms in women were chest discomfort (57%), shortness of breath (57.9%), weakness (54.8%), and fatigue (42.9%).

Media Campaigns and Public Education to Improve Symptom Recognition

Intense public education can increase patient knowledge of heart attack symptoms and the need to call 911/seek medical attention quickly, but it has not been consistently successful in shortening patient delay in executing these actions.²⁴^,²⁵ Ho et al.²⁵ were the first U.S. investigators to prospectively evaluate the effect of a 7-month public education campaign on AMI patient health-seeking delay and EMS use in King County, WA. The goal of the educational intervention was to increase the public’s knowledge of AMI symptoms and encourage anyone with such symptoms to “Call 911, Call Fast.” The investigators showed that the public’s knowledge of AMI symptoms and the need to call 911 quickly increased significantly in the postmessage period (premessage, 53%; postmessage, 74%; P <0.0001). However, the campaign failed to shorten significantly AMI patient delay in seeking medical care (median delay premessage, 2.6 hours; postmessage, 2.3 hours) or alter the distribution of patients in the time intervals of <2 hours, 2 to 4 hours, and >4 hours. The rate of EMS use did not change significantly (premessage, 42%; postmessage, 44%), prompting the authors to conclude that the short-duration public educational campaign increased knowledge of AMI symptoms and appropriate health-seeking actions but did not alter AMI patient behavior.

Soon after this publication, Herlitz et al.²⁶ reported the results of a media campaign aimed at reducing delay times in suspected AMI on the volume of emergency department (ED) chest pain patients in Goteborg, Sweden. During the first week of the campaign, the mean
number of patients with chest pain increased from 10.5 to 25.4 per day. However, the number declined rapidly over the next several months. The average ED volume increased by 9% during the entire media campaign, while the number of confirmed AMI patients increased by only 6%. The greatest increase was observed in patients with chest discomfort in whom AMI was not suspected after physician evaluation.

Intense public education can increase patient knowledge of heart attack symptoms and the need to call 911/seek medical attention quickly, but it has not been consistently successful in shortening patient delay in executing these actions. Despite these somewhat “mixed” results, prudence would dictate that public education is necessary, albeit perhaps insufficient, to improve ACS patient health-seeking behavior.

In 1996, Blohm et al.²⁷

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