The present study was designed to assess the value of the presenting symptom of “typical” anginal pain, “atypical/nonanginal” pain, or the lack of chest pain in predicting the presence of inducible myocardial ischemia using cardiac stress testing in emergency department patients being evaluated for possible acute coronary syndrome. We performed a retrospective observational study of adult patients who were evaluated for acute coronary syndrome in an emergency department chest pain unit. The presenting symptoms were obtained from a structured questionnaire administered before stress testing. Patient chest pain was categorized according to the presence of substernal chest pain or discomfort that was provoked by exertion or emotional stress and was relieved by rest and/or nitroglycerin. Chest pain was classified as “typical” angina if all 3 descriptors were present and “atypical” or “nonanginal” if <3 descriptors were present. All patients underwent serial biomarker and cardiac stress testing before discharge. A total of 2,525 patients met the eligibility criteria. Inducible ischemia on stress testing was found in 33 (14%, 95% confidence interval 10% to 19%) of the 231 patients who had typical anginal pain, 238 (11%, 95% confidence interval 10% to 13%) of the 2,140 patients presenting with atypical/nonanginal chest pain, and 25 (16%, 95% confidence interval 11% to 22%) of the 153 patients who had no complaint of chest pain on presentation. Compared to patients with atypical or no chest pain, patients with typical chest pain were not significantly more likely to have inducible ischemia on stress testing (likelihood ratio +1.25, 95% confidence interval 0.89 to 1.78). In conclusion, in our study, the patients who presented with “typical” angina were no more likely to have inducible myocardial ischemia on stress testing than patients with other presenting symptoms.
Although it has long been recognized that patients with acute coronary syndromes (ACSs) can present with atypical symptoms, it has been commonly believed that patients who present with symptoms that meet the strict criteria for “typical” angina have a greater probability of obstructive coronary artery disease (CAD). If true, the presence of “typical” anginal pain should allow clinicians to easily identify a group of patients for whom diagnostic (ie, cardiac catheterization vs stress testing) and disposition (ie, admission vs observation) decisions can be appropriately made according to the patient’s high pretest probability of disease. The belief that the probability of obstructive CAD can be determined by the presenting symptoms has been based on studies that were performed decades ago on patients unlikely to represent a present-day emergency department (ED) population. In this study of ED patients evaluated for ACS in an observation unit setting, we investigated the test characteristics of the patients’ initial presenting complaint. The goal of this investigation was to evaluate the accuracy of a presenting symptom of typical anginal pain, atypical/nonanginal pain, or a lack of chest pain in predicting the presence of inducible myocardial ischemia (IMI) using cardiac stress testing in ED patients being evaluated for possible ACS. Based on the results from previous studies of non-ED patients, the symptoms that met the predefined criteria for “typical” angina should be more predictive of IMI than other presenting complaints. From our clinical experience with ED patients, we hypothesized this would not be true.
Methods
We performed a retrospective observational study of all patients who were evaluated for ACS in an ED-based chest pain unit with serial biomarkers and had undergone cardiac stress testing before discharge. The institutional review board of Mount Sinai Medical Center (New York, New York) approved this study.
The present study was conducted in the ED chest pain unit of an urban academic tertiary care center from March 2004 to May 2008. The annual ED census is >90,000 patients, and the observation unit evaluates >700 eligible patients annually for potential ACS. Our ED evaluates 3,800 to 4,500 patients annually for undifferentiated chest pain. Of these patients, approximately 60% are discharged home from the ED without prolonged observation or cardiac testing. Of the patients who are kept for additional evaluation, 30% are placed in the observation unit to rule out ACS, 51% are admitted to a telemetry floor, and 19% are taken directly to the catheterization laboratory for a diagnostic or an interventional procedure. Approximately 18% of all patients evaluated in the chest pain unit during the study period demonstrated stress test results consistent with IMI.
All patients without a history of previous myocardial infarction or previous revascularization who were admitted to the observation unit for the evaluation of ACS and completed provocative testing during the study period were considered eligible for the present study. The admission criteria for the observation unit, which are based on previously published risk factors for adverse events in ED patients with chest pain, focus a given patient’s risk of near-term complications rather than an assessment of the probability of obstructive CAD ( Table 1 ). Thus, patients who might be described as moderate to high risk of obstructive CAD because of age, gender, traditional cardiac risk factors, and/or the nature of the presenting symptoms are often placed in the unit. No upper or lower age limit was used to be eligible for the present study.
| Clinical concern for myocardial ischemia according presenting complaint as determined by attending emergency department physician, with none of following high-risk features ⁎ |
| Electrocardiographic evidence of myocardial ischemia or infarction (new or not known to be old) |
| ST-segment depression >0.1 mV measured 80 ms from J point or inverted T waves >0.3 mV |
| ST-segment elevation >0.1 mV measured 80 ms from J point in ≥2 contiguous leads or Q waves ≥30 ms and 0.1 mV in depth |
| Clinical evidence of heart failure |
| Initial systolic blood pressure <100 mm Hg |
| Worsening of previously stable angina pectoris |
| Pain same as for previous myocardial infarction |
⁎ Data from Goldman L, Cook EF, Johnson PA, Brand DA, Rouan GW, Lee TH. Prediction of the need for intensive care in patients who come to the emergency departments with acute chest pain. N Engl J Med 1996;334:1498–1504.
According to the noninvasive cardiology laboratory protocol, the patient data, including the nature of the presenting symptoms, was obtained before stress testing using a structured patient questionnaire that was administered by either a registered nurse or cardiology fellow, with the data subsequently entered into a clinical database. Patient chest pain was categorized according to the presence of substernal chest pain or discomfort that was provoked by exertion or emotional stress and was relieved by rest and/or nitroglycerin. Chest pain was classified as “typical” angina if all 3 descriptors were present and as atypical or nonanginal if <3 descriptors were present, as defined by the American College of Cardiology/American Heart Association 2002 Guideline Update on Exercise Testing.
Information, including age, gender, and traditional cardiac risk factors, was also collected for each patient ( Table 2 ). Additionally, the type and results of the provocative cardiac testing were recorded for each patient and classified into 1 of 2 categories: (1) negative, no evidence of IMI; or (2) positive, perfusion abnormality consistent with IMI ( Table 3 ). During the study period, 1,026 patients underwent pharmacologic myocardial sestamibi testing, 1,309 patients underwent exercise myocardial sestamibi studies, and 190 patients were evaluated using only exercise stress electrocardiography.
| Variable | Total | Typical Anginal Pain | Atypical, Nonanginal Pain | No Chest Pain |
|---|---|---|---|---|
| Total | 2,524 | 231 | 2140 | 153 |
| Age (years) | ||||
| Men | 980 | 50.7 ± 12.0 | 51.2 ± 12.8 | 57.2 ± 15.1 |
| Women | 1,544 | 56.1 ± 12.6 | 56.7 ± 13.9 | 62.5 ± 13.8 |
| Diabetes mellitus | ||||
| Yes | 487 | 49 (10%) | 394 (81%) | 44 (9%) |
| No | 2,037 | 182 (9%) | 1,743 (86%) | 112 (6%) |
| Menopausal status | ||||
| Premenopausal | 475 | 37 (8%) | 418 (88%) | 20 (4%) |
| Postmenopausal | 763 | 62 (8%) | 645 (85%) | 56 (7%) |
| After hysterectomy | 306 | 39 (13%) | 255 (83%) | 12 (4%) |
| Hypertension | ||||
| Yes | 1386 | 131 | 1,157 | 98 |
| No | 1,138 | 100 | 983 | 55 |
| Family history of premature coronary atherosclerotic disease | ||||
| Yes | 317 | 39 | 266 | 12 |
| No | 2,130 | 192 | 1,874 | 141 |
| Hyperlipidemia (by patient report) | ||||
| Yes | 901 | 84 | 768 | 49 |
| No | 1,623 | 147 | 1,372 | 104 |
| Smoker | ||||
| Yes | 1,228 | 108 | 1,047 | 74 |
| No | 1,296 | 123 | 1,093 | 79 |
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