Long-term survival of emergency department patients with acute chest pain

A 14-year follow-up study of chest pain patients including stress hormones and mental stress at index event

BACKGROUND

Knowledge of long-term outcome in chest pain patients is limited. We reinvestigated patients who 14 years earlier had visited the emergency department due to chest pain, and were discharged without hospitalization. Extensive examinations were made at that time on 484 patients including full medical history, exercise test, a battery of stress questions and stress hormone sampling.

METHODS

From a previously conducted chest pain study patients still alive after 14 years were approached. Hospitalization or deaths with a diagnosis of ischemic heart disease or cerebrovascular disease were used as end point.

RESULTS

During the follow-up period 24 patients had died with a diagnosis of ischemic heart or cerebrovascular disease, and 50 patients had been given such a diagnosis at hospital discharge. Age (OR 1.12, CI 1.06-1.19), previous history of angina pectoris (OR 9.69, CI 2.06-71.61), pathological ECG at emergency department visit (OR 3.27, CI 1.23-8.67), hypertension (OR 5.03, CI 1.90-13.76), smoking (OR 3.04, CI 1.26-7.63) and lipid lowering medication (OR 14.9, CI 1.60-152.77) were all associated with future ischemic heart or cerebrovascular events. Noradrenalin levels were higher in the event group than in the non-event group, mean (SD) 2.44 (1.02) nmol/L versus 1.90 (0.75) nmol/L. When noradrenalin was included in the regression model high maximal exercise capacity was protective of an event (OR 0.986, CI 0.975-0.997).

CONCLUSION

In chest pain patients previous history of angina pectoris, hypertension, smoking, pathological ECG at primary examination, and age were the main risk factors associated with future cardiovascular or cerebrovascular events.

Incremental value of myocardial perfusion over regional left ventricular function and coronary stenosis by cardiac CT for the detection of acute coronary syndromes in high-risk patients: a subgroup analysis of the ROMICAT trial

OBJECTIVES

To determine the incremental benefit of assessing myocardial perfusion defects (MPD) for acute coronary syndromes (ACS) over coronary and functional assessment by rest cardiac computed tomography (CT) in patients with acute chest pain.

BACKGROUND

Assessment of myocardial perfusion is feasible with cardiac CT; however, the diagnostic value of this assessment in patients at risk for ACS has not been demonstrated.

METHODS

The study included patients who presented to the emergency department with acute chest pain, nonischemic initial electrocardiogram (ECG), and negative cardiac biomarkers but had clinical suspicion for ACS and underwent invasive coronary angiography (ICA). Results were blinded to caregivers and patients. CT data sets were independently assessed for the presence of coronary plaque and stenosis, regional left ventricular function, and myocardial perfusion deficits by 2 blinded observers. Coronary angiography was assessed for the presence of stenosis, TIMI myocardial perfusion grade, and corrected TIMI frame count. The endpoint was ACS during index hospitalization.

RESULTS

We analyzed data from 35 subjects (69% male, mean age 58 ± 9 years) of whom 22 (63%) had ACS. The sensitivity and specificity of MPD for ACS were 86% (95% CI: 64%-96%) and 62% (95% CI: 32%-85%), respectively. Combined, MPD and RWMA assessment resulted in specificity and sensitivity of 86% (95% CI: 64%-96%) and 85% (95% CI: 54%-97%), respectively. Adding MPD and RWMA to the assessment for significant stenosis (>50%) resulted in a higher sensitivity of 91% (69-98%) and specificity of 85% (54-97%) and a significantly increased overall diagnostic accuracy when compared with assessment for stenosis (AUC: 0.88 vs 0.79; respectively, P = 0.02). Diagnostic accuracy of CT was not associated with impaired CTFC >40 or myocardial TIMI perfusion grade < 3.

CONCLUSIONS

Assessment of myocardial perfusion and regional wall motion abnormalities may enhance the ability of CT to detect ACS in patients with acute chest pain.

Direct hospital costs of chest pain patients attending the emergency department: a retrospective study

Background

Chest pain is one of the most common complaints in the Emergency Department (ED), but the cost of ED chest pain patients is unclear. The aim of this study was to describe the direct hospital costs for unselected chest pain patients attending the emergency department (ED).

Methods

1,000 consecutive ED visits of patients with chest pain were retrospectively included. Costs directly following the ED visit were retrieved from the hospital economy system.

Results

The mean cost per patient visit was 26.8 thousand Swedish kronar (kSEK) (median 7.2 kSEK), with admission time accounting for 73% of all costs. Mean cost for patients discharged from the ED was 1.4 kSEK (median 1.3 kSEK), and for patients without ACS admitted 1 day or less 7.6 kSEK (median 6.9 kSEK). The practice in the present study to admit 67% of the patients, of whom only 31% proved to have ACS, was estimated to give a cost per additional life-year saved by hospital admission, compared to theoretical strategy of discharging all patients home, of about 350 kSEK (39 kEUR or 42 kUSD).

Conclusion

Costs for chest pain patients are large and primarily due to admission time. The present admission practice seems to be cost-effective, but the substantial overadmission indicates that better ED diagnostics and triage could decrease costs considerably.

Disagreement in the interpretation of electrocardiographic ST segment elevation: a source of error for emergency physicians?

Evaluation of the electrocardiogram (ECG) is a complex, subjective process with the potential for interobserver disagreement. The objective of this study was to determine the ECG patterns with discrepant interpretations, the rates of disagreement in the determination of both the presence of ST segment elevation (STE) and morphology. ECGs were reviewed in a retrospective fashion by attending EPs for STE and waveform morphology. Those ECGs that were interpreted in a discrepant fashion were then analyzed to detect patterns of disagreement. ECGs from 599 patients were reviewed. Two hundred eleven patients (35.2% of the total patient population surveyed) had STE as determined by at least one attending EP; 40 (19% of the STE population) patients had STE determined by 1 EP, 21 (10% of the STE population) patients by 2 EPs, and 150 (71% of the STE population) patients by 3 EPs. The STE of 61 (28.9%) ECGs were interpreted in a discrepant fashion. The average STE was 1.31 mm per lead for ECGs with disagreement and 2.93 mm per lead for ECGs with agreement (P<.05). ECGs with reciprocal ST depression were more likely to have agreement with regard to the STE (P<.05). Fourteen ECGs (8.2% of 171 ECGs with STE determined by at least 2 EPs) had ST segment morphology interpreted in a discrepant fashion. Disagreement in the determination of electrocardiographic ST segment elevation by EPs occurs frequently and is related to the amount of STE present on the ECG. Electrocardiographic patterns responsible for this interpretive disagreement of ST segment elevation can represent an unfortunate but potentially predictable source of error in emergency medical care.

Cost effectiveness of diagnostic strategies for patients with acute, undifferentiated chest pain

OBJECTIVES

Patients presenting to hospital with acute, undifferentiated chest pain have a low, but important, risk of significant myocardial ischaemia. Potential diagnostic strategies for patients with acute, undifferentiated chest pain vary from low cost, poor effectiveness (discharging all home) to high cost, high effectiveness (admission and intensive investigation). This paper aimed to estimate the relative cost effectiveness of these strategies.

METHODS

Decision analysis modelling was used to measure the incremental cost per quality adjusted year of life (QALY) gained for five potential strategies to diagnose acute undifferentiated chest pain, compared with the next most effective strategy, or a baseline strategy of discharging all patients home without further testing.

RESULTS

Cardiac enzyme testing alone costs pound 17 432/QALY compared with discharge without testing. Adding two to six hours of observation and repeat enzyme testing costs an additional pound 18 567/QALY. Adding exercise testing to this strategy costs pound 28 553/QALY. A strategy of overnight admission, enzyme, and exercise testing has an incremental cost of pound 120 369/QALY, while a strategy consisting of overnight admission without exercise testing is subject to extended dominance. Sensitivity analysis revealed that the results are sensitive to variations in the direct costs of running each strategy and to variation in assumptions regarding the effect of diagnostic testing upon quality of life of those with non-cardiac disease.

CONCLUSION

Observation based strategies incur similar costs per QALY to presently funded interventions for coronary heart disease, while strategies requiring hospital admission may be prohibitively poor value for money. Validation of the true costs and effects of observation based strategies is essential before widespread implementation.

Critical pathways for patients with acute chest pain at low risk

Critical pathways are predefined protocols that define the crucial steps in evaluating and treating a clinical problem to improve quality of patient care, reduce variability and enhance efficiency. Critical pathways have proliferated for a variety of diagnoses, including evaluation of patients with chest pain, a common and costly complaint. This review will outline the development, implementation, and assessment of critical pathways using as a paradigm our experience with a pathway for patients presenting to the Emergency Department with acute chest pain who are at low risk of myocardial ischemia. The goals of the pathway were to expedite evaluation of low-risk patients and reduce admission rates among these patients and in the cohort overall without compromising outcomes. The pathway was developed by a multidisciplinary team in an iterative process that considered published literature, as well as the experience and consensus of local opinion leaders. Patients at least 30 years old presenting to the Emergency Department of an urban teaching hospital who were pain-free without heart failure or ischemic changes on EKG, but who were not considered appropriate for discharge by the treating physician, were eligible for the critical pathway. The pathway involved one set of creatine kinase-MB enzymes drawn at least 4 hours after pain, a 6 hour observation period after the last episode of pain and exercise testing. Outcomes during evaluation and admission rates were assessed. Clinical outcomes at 7 days and 6 months after evaluation and patient satisfaction at 7 days were also measured. Of 1363 patient visits, 145 (10.6%) were triaged by the pathway: 131 (90.3%) were discharged, 14 (9.7%) were admitted. The overall admission rate decreased from 63% (2898/4595) to 60% (819/1363) [p < 0.05] in comparison to a cohort studied prior to pathway implementation. Pathway patients reported low rates of subsequent cardiac procedures. No deaths or myocardial infarctions were recorded. At 7 days, only 2 respondents (2%) reported going to an Emergency Department since their evaluation. Most respondents (83%) rated their care as very good or excellent. Critical pathways designed to enhance efficiency, reduce variability, and improve the quality of care are becoming increasingly common. Our pathway for evaluation of patients with chest pain at low risk of myocardial ischemia was feasible and safe and was associated with a decline in absolute admission rates. Because of the possibility of concomitant secular trends and the effects of a changing medical environment, further rigorous research on the efficacy of individual pathways is needed.

Prevention of coronary heart disease through treatment of infection with Chlamydia pneumoniae? Estimation of possible effectiveness and costs

Evidence has been accumulating for a link between Chlamydia pneumoniae and coronary heart disease (CHD). A spreadsheet model was used to estimate the impact of different strategies for screening and treating C. pneumoniae on the incidence of myocardial infarction and cardiac mortality over a 1-year post-intervention period. It was found that screening would potentially be most cost-effective in men aged over 35 with a history of myocardial infarction (around ł2,000 per life-year saved). Cost-effectiveness would be inferior in those with established heart disease but no history of myocardial infarction (MI), and poor for people at elevated risk of CHD. If causality of the association were proven, the cost-effectiveness of treating C. pneumoniae in post-MI patients would compare favourably with, for example, statins for treating hypercholesterolaemia.

Chest pain unit and decentralized testing of cardiac markers

Chest pain is one of the most important reasons of Emergency Department arrivals (5% of total). As it is not possible to rule-in all patients claiming chest pain, it has been proposed to create new departments to monitor these patients during some hours, in order to exclude or confirm an acute coronary syndrome. These departments are named Chest Pain Units (CPUs). The Chest Pain Unit has been created since June 1998 in Alessandria Hospital "SS. Antonio e Biagio e C. Arrigo". Chest Pain Unit patients presenting in Emergency Department with an unclear defined chest pain are submitted to a continuous ECG monitoring of S-T trend for 24 h. Moreover, cardiac markers such as myoglobin, mass CK-MB and Troponin-I are tested at arrival and Troponin-I is tested again serially 3, 6, 9, 18 h after the first sampling. It is really important to be able to measure these markers of myocardial damage with robust and quick methods. A point-of-care analyzer is available in our chest pain unit and enables our department to obtain results in a very short time at low cost and with quality similar to that of clinical chemistry laboratories' instruments. This easy-to-use analyzer can be run by nurses without interfering in their normal activities. The presentation of our experience will be completed by describing all patients admitted in our Chest Pain Units from January to June 1998.

Characteristics and outcomes of young adults who present to the emergency department with chest pain

BACKGROUND

Most studies of emergency department (ED) chest pain patients exclude patients <30-40 years old. As a result, the clinical course of these patients is poorly described.

OBJECTIVE

To study the clinical characteristics, hospital course, and 30-day outcomes of ED chest pain patients <40 years old. The hypothesis was that patients <40 years old without a cardiac history and with normal electro-cardiograms (ECGs) or no cardiac risk factors would be at a <1% risk for acute coronary syndromes (ACSs) and 30-day adverse cardiovascular (CV) events.

METHODS

This was a prospective cohort study of non-cocaine-using ED patients, 24-39 years old, who received an ECG for chest pain between July 9, 1999, and October 23, 2000. Structured data collection at presentation included demographics, chest pain description, history, laboratory, and ECG data. Hospital course was followed daily. Thirty-day follow-up was performed by telephone. The main outcomes were discharge diagnosis and 30-day adverse CV events [acute myocardial infarction (AMI), death, percutaneous intervention (PCI), or coronary artery bypass grafting (CABG)].

RESULTS

A total of 487 patients presented 527 times and comprised the study group. Patients were most often 30-39 years old (71%), female (60%), and African-American (73%). Thirty-two percent were admitted. Five hundred seven of 527 patient visits (96%) had 30-day follow-up. Patients had the following cardiac risk factors: tobacco, 37%; hypertension, 22%; family history, 19%; diabetes mellitus, 6%; cholesterol, 6%; prior angina, 3%; known coronary artery disease, 3%; and prior AMI, 2%. Patients usually had unremarkable ECGs (61% normal, 98% nonischemic). Overall, 11 of 527 patients had adverse CV events (2.1%; 95% CI = 0.9% to 3.3%): 8 AMIs (1.5%), 4 deaths (0.8%), 5 PCIs (0.9%), and no CABG. Twenty-five patients had a final diagnosis of ACS (4.7%; 95% CI = 2.9% to 6.5%). The incidence of ACS in the 210 patients without a cardiac history and without cardiac risk factors was 0.5% (95% CI = 0% to 1.4%). At 30 days, none of these 210 patients had AMI, PCI, CABG, or death (0%, 95% CI = 0% to 1.4%). The incidence of ACS in the 312 patients with normal ECGs and a negative cardiac history was 0.3% (95% CI = 0% to 0.9%). At 30 days, there was no AMI, PCI, or CABG in these 312 patients, and one patient with metastatic cancer died (adverse CV event 0.3%, 95% CI = 0% to 0.9%).

CONCLUSIONS

Although young patients, as a whole, have a 4.7% risk of ACSs and a 2.1% risk of adverse CV events at 30 days, those without known cardiac disease or any cardiac risk factors had a <1% risk of ACSs and were free from adverse CV events over 30 days. Likewise, young patients without a cardiac history and with a normal ECG had a <1% risk of ACSs and adverse CV events at 30 days. It may be reasonable to expedite outpatient management and limit unnecessary admissions in these cohorts.

Randomized comparison of a strategy of predischarge coronary angiography versus exercise testing in low-risk patients in a chest pain unit: in-hospital and long-term outcomes

OBJECTIVES

This randomized trial compared a strategy of predischarge coronary angiography (CA) with exercise treadmill testing (ETT) in low-risk patients in the chest pain unit (CPU) to reduce repeat emergency department (ED) visits and to identify additional coronary artery disease (CAD).

BACKGROUND

Patients with chest pain and normal electrocardiograms (ECGs) have a low likelihood of CAD and a favorable prognosis, but they often seek repeat evaluations in EDs. Remaining uncertainty regarding their symptoms and diagnosis may cause much of this recidivism.

METHODS

A total of 248 patients with no ischemic ECG changes triaged to a CPU were randomized to CA (n = 123) or ETT (n = 125). All patients had a probability of myocardial infarction < or =7% according to the Goldman algorithm, no biochemical evidence of infarction, the ability to exercise and no previous documented CAD. Patients were followed up for > or =1 year and surveyed regarding their chest pain self-perception and utility of the index evaluation.

RESULTS

Coronary angiography showed disease (> or =50% stenosis) in 19% and ETT was positive in 7% of the patients (p = 0.01). During follow-up (374+/-61 days), patients with a negative CA had fewer returns to the ED (10% vs. 30%, p = 0.0008) and hospital admissions (3% vs. 16%, p = 0.003), compared with patients with a negative/nondiagnostic ETT. The latter group was more likely to consider their pain as cardiac-related (15% vs. 7%), to be unsure about its etiology (38% vs. 26%) and to judge their evaluation as not useful (39% vs. 15%) (p < 0.01 for all comparisons).

CONCLUSIONS

In low-risk patients in the CPU, a strategy of CA detects more CAD than ETT, reduces long-term ED and hospital utilization and yields better patient satisfaction and understanding of their condition.

PITFALLS IN THE EMERGENCY DEPARTMENT DIAGNOSIS OF ACUTE MYOCARDIAL INFARCTION

The accurate assessment and triage of patients with potential ACS is a complex decision-making process based on information that is not entirely reliable. The knowledgeable EP recognizes that assessment of patients with chest pain requires an understanding of the various clinical presentations of ACS and high-risk patient types, as well as careful use of the available modalities to diagnose these syndromes efficiently while incurring minimal risk to the patients safety. The busy EP is faced with sick patients with chest pain daily, so that it behoove anyone in emergency medicine to familiarize themselves with these diagnostic pitfalls.

Stress testing for risk stratification of patients with low to moderate probability of acute cardiac ischemia

In summary, this article focused on the use of stress testing to risk-stratify patients at the conclusion of their emergency evaluation for ACI. As discussed, those patients in the probably not ACI category require additional risk stratification prior to discharge. It should be kept in mind that patients in this category are heterogeneous, containing subgroups at both higher and lower risk of ACI and cardiac events. The patients with lower pretest probability for ACI may only need exercise testing in the ED. Patients with higher pretest probability should undergo myocardial perfusion or echocardiographic stress testing to maximize diagnostic and prognostic information. Prognostic information is the key to provocative testing in the ED. Prognostic information is the component that will help emergency physicians identify the patients who may be discharged home safely without having to worry about a 6% annual cardiac death rate and a 10% overall death rate over the next 30 months. Stress testing provides this key prognostic data, and it can be obtained in short-stay chest pain observation units in a safe, timely, and cost-effective fashion.

Outcome analysis of chest pain patients discharged from the ED--a pilot study

The objective of this pilot study was to determine clinical predictors of adverse outcome, defined as myocardial infarction, angioplasy or stent placement, coronary artery bypass graft, or death, within 60 days for patients discharged from the emergency department with a presenting complaint of chest pain. All patients presenting to the emergency department with a chief complaint of chest pain were eligible for the study. A chest pain risk analysis sheet was completed as part of the patient evaluation. Patients discharged from the emergency department, in whom a risk analysis sheet was completed, were contacted to determine their clinical course within 60 days of their discharge from the emergency department. During the 6-month study period, 129 eligible patients were enrolled. Of these 129 patients, four had an adverse outcome within 60 days of their discharge. All four patients had either a balloon angioplasty procedure, coronary artery bypass graft, or both. None of the study patients had a myocardial infarction or died. Statistically significant predictors of adverse outcome in our study population were an abnormal electrocardiogram (ECG), a history of myocardial infarction, and a history of hypertension. In conclusion, patients discharged from the emergency department with a presenting complaint of chest pain were at a low risk for having a myocardial infarction or dying within 60 days of their discharge. Several patients, however, did have significant coronary artery disease requiring angioplasty or bypass. These patients were more likely to have an abnormal ECG, a history of myocardial infarction, or have a history of hypertension. A prospective study with larger numbers of patients is needed to validate these findings.

Cardiac troponin T in chest pain unit patients without ischemic electrocardiographic changes: angiographic correlates and long-term clinical outcomes

OBJECTIVES

We prospectively evaluated the relation between cardiac troponin T (cTnT) level, the presence and severity of coronary artery disease (CAD) and long-term prognosis in patients with chest pain but no ischemic electrocardiographic (ECG) changes who had short-term observation.

BACKGROUND

Cardiac TnT is a powerful predictor of future myocardial infarction (MI) and death in patients with ECG evidence of an acute coronary syndrome. However, for patients with chest pain with normal ECGs, it has not been determined whether cTnT elevation is predictive of CAD and a poor long-term prognosis.

METHODS

In 414 consecutive patients with no ischemic ECG changes who were triaged to a chest pain unit, cTnT and creatine kinase, MB fraction (CK-MB) were evaluated > or = 10 h after symptom onset. Patients with adverse cardiac events, including death, MI, unstable angina and heart failure were followed for as long as one year.

RESULTS

A positive (>0.1 ng/ml) cTnT test was detected in 37 patients (8.9%). Coronary artery disease was found in 90% of 30 cTnT-positive patients versus 23% of 144 cTnT-negative patients who underwent angiography (p < 0.001), with multivessel disease in 63% versus 13% (p < 0.001). The cTnT-positive patients had a significantly (p < 0.05) higher percent diameter stenosis and a greater frequency of calcified, complex and occlusive lesions. Follow-up was available in 405 patients (98%). By one year, 59 patients (14.6%) had adverse cardiac events. The cumulative adverse event rate was 32.4% in cTnT-positive patients versus 12.8% in cTnT-negative patients (p = 0.001). After adjustment for baseline clinical characteristics, positive cTnT was a stronger predictor of events (chi-square = 23.56, p = 0.0003) than positive CK-MB (>5 ng/ml) (chi-square = 21.08, p = 0.0008). In a model including both biochemical markers, CK-MB added no predictive information as compared with cTnT alone (chi-square = 23.57, p = 0.0006).

CONCLUSIONS

In a group of patients with chest pain anticipated to have a low prevalence of CAD and a good prognosis, cTnT identifies a subgroup with a high prevalence of extensive and complex CAD and increased risk for long-term adverse outcomes.

Serial use of bedside CKMB/myoglobin device to detect acute myocardial infarction in emergency department chest pain patients

A qualitative bedside device (Spectral Diagnostics, Toronto, Canada) for CKMB and myoglobin (MYOG) detection was evaluated in emergency department (ED) patients with chest pain to determine performance characteristics. At presentation (0 h) and at three hours (3 h), serum was analyzed in the ED with results considered positive if either 0-h or 3-h CKMB or MYOG bands were visible. The results were compared with the diagnosis of myocardial infarction (MI) per hospital discharge diagnosis (n = 132, 87%) or telephone follow-up (n = 19; 1 patient lost to follow-up). Of 151 study patients, 30 (20%) were diagnosed with MI; all were admitted to hospital. On electrocardiogram (EKG), 17 (57%) MI patients had ST-segment elevation. At 0-h, 26 of 30 (87%) MI patients were positive for CKMB/MYOG. By 3 h, 21 of 23 (91%) MI patients were positive for CKMB/MYOG; 7 MI patients were already admitted to hospital. Combining 0-h and 3-h results, the device sensitivity for MI was 93% (28/30) with specificity of 54%. Combining device results plus diagnostic EKG, sensitivity was found to be 100% (30/30). If the device result was positive, then the odds ratio for having an ischemic complication was 6.5. We conclude that the CKMB/MYOG device identified most MI patients at ED presentation and 3 h later. Combining device results with EKG detected all MI patients in the ED.

Early use of coronary angiography and intervention

In this article we have outlined the current rationale and role of invasive management in ACS. For the majority of patients with ACS, who are either at high risk or unstable, invasive management is a critical element in breaking the sequence of recurrent ischemia leading to early cardiac events (Fig. 11). Secular trends in the care of cardiovascular patients predict even more sophisticated, invasive methods of treating coronary occlusion in the future. A futurist's view on this subject may envision the following type of scenario. A patient with prior CAD experiences persistent chest pain and notifies the emergency medical system. The paramedics arrive, and perform a rapid fingerstick cardiac biomarker panel and ECG. The results are interpreted by an emergency physician via a telecommunication system, and the patient is determined to be at high risk. He or she is triaged to a center capable of angioplasty and bypass surgery. On the way to the hospital, the patient is treated with aspirin, IV heparin, and an IV glycoprotein IIb/IIIa inhibitor. The patient undergoes triage angiography within 1 hour of hospital arrival, culprit lesion(s) are identified, and a revascularization plan is made--setting a critical pathway that is definitive. This vision is not far off on the horizon. We anticipate additional clinical trial results will help form the decision points in this optimal treatment scenario, which for a large proportion of patients will involve invasive management.

Evaluation and risk stratification of patients with chest pain in the emergency department. Predictors of life-threatening events

While assessing chest pain in the emergency department, physicians must first estimate the probability of acute ischemic states in the patient. This first estimate is based on the patient's history, physical examination, and electrocardiogram. Patients who meet the threshold for acute cardiac ischemia are further evaluated to confirm or exclude this diagnosis, while other life-threatening factors are excluded.

Educational Strategies to Prevent Prehospital Delay in Patients at High Risk for Acute Myocardial Infarction: A Report by the National Heart Attack Alert Program

An estimated 13 million people in the United States have coronary heart disease (CHD), peripheral vascular disease, or cerebrovascular disease. The risk for subsequent myocardial infarction (MI) and death in these patients is fivefold to sevenfold higher than for the general population. Many effective therapies are now available for patients with unstable angina, acute myocardial infarction (AMI), potentially fatal arrhythmias, and cardiogenic shock if they seek and receive care expeditiously. However, delays in accessing and receiving care are a continuing problem, threatening the effectiveness of available treatments. Patients with previously diagnosed CHD, including a previous MI, have the same or greater delay times as those without prior MI or CHD. Because of the high-risk status of these patients, combined with the problem of delay in seeking care, this Working Group of the National Heart Attack Alert Program Coordinating Committee advises physicians and other healthcare providers of their important role in reducing treatment delay in these patients. The Working Group recommends that primary care clinicians in the office and in inpatient settings provide these patients and their family members or significant others with contingency counseling about actions to take in response to symptoms of an AMI. The counseling should address the emotional aspects (e.g., fear and denial) that patients and those around them may experience, as well as barriers that may be associated with the healthcare delivery system. Assistance from other healthcare providers (e.g., nurses) should be solicited to initiate, reinforce, and supplement the counseling. A Patient Advisory Form is offered as an aid to providers in counseling their high-risk patients about these issues. Other materials and aids should be considered as well. Physicians' offices and clinics should devise a system to triage patients rapidly when they call or walk in seeking advice for possible AMI symptoms. Further research is needed to learn more about effective counseling strategies; symptom manifestation in high-risk groups, including the elderly, women, and minorities; and healthcare delivery systems that enhance access to timely care for patients with prior CHD or other clinical atherosclerotic disease.

Clinical value of acute rest technetium-99m tetrofosmin tomographic myocardial perfusion imaging in patients with acute chest pain and nondiagnostic electrocardiograms

OBJECTIVES

We sought to evaluate the clinical use and cost-analysis of acute rest technetium-99m (Tc-99m) tetrofosmin single-photon emission computed tomographic (SPECT) myocardial perfusion imaging in patients with chest pain and a normal electrocardiogram (ECG).

BACKGROUND

Current approaches used in emergency departments (EDs) for treating patients presenting with chest pain and a nondiagnostic ECG result in poor resource utilization.

METHODS

Three hundred fifty-seven patients presenting to six centers with symptoms suggestive of myocardial ischemia and a nondiagnostic ECG underwent Tc-99m tetrofosmin SPECT during or within 6 h of symptoms. Follow-up evaluation was performed during the hospital period and 30 days after discharge. All entry ECGs, SPECT images and cardiac events were reviewed in blinded manner and were not available to the admitting physicians.

RESULTS

By consensus interpretation, 204 images (57%) were normal, and 153 were abnormal (43%). Of 20 patients (6%) with an acute myocardial infarction (MI) during the hospital period, 18 had abnormal images (sensitivity 90%), whereas only 2 had normal images (negative predictive value 99%). Multiple logistic regression analysis demonstrated abnormal SPECT imaging to be the best predictor of MI and significantly better than clinical data. Using a normal SPECT image as a criterion not to admit patients would result in a 57% reduction in hospital admissions, with a mean cost savings per patient of $4,258.

CONCLUSIONS

Abnormal rest Tc-99m tetrofosmin SPECT imaging accurately predicts acute MI in patients with symptoms and a nondiagnostic ECG, whereas a normal study is associated with a very low cardiac event rate. The use of acute rest SPECT imaging in the ED can substantially and safely reduce the number of unnecessary hospital admissions.

Clinical and echocardiographic correlates of health status in patients with acute chest pain

OBJECTIVE

To assess the ability of echocardiographic data to predict important functional status outcomes in patients with chest pain.

DESIGN

Prospective cohort study.

SETTING

A large, urban teaching hospital.

PATIENTS

Three hundred thirty-three patients admitted from the Emergency Department for evaluation of chest pain.

MEASUREMENTS AND MAIN RESULTS

Patients underwent two-dimensional and Doppler echocardiography as well as a face-to-face interview during their initial hospitalization and a telephone interview 1 year thereafter. The interview included the Medical Outcomes Study 36-Item Short Form (SF-36) health inventory, a generic health status instrument with a physical function subscale. The relation between clinical and echocardiographic factors and functional status was explored by univariable and multivariable linear regression and logistic regression analyses. Multiple clinical and echocardiographic factors correlated significantly with functional status measures at 1 year. For the SF-36 score at 1 year, age, male gender, white race, the presence of rales, and a comorbidity score were independently predictors in multivariate analysis; echocardiographic findings of severe left ventricular dysfunction (parameter estimate [PE] -27.6; 95% confidence interval [CI] -43.1, -12.2) and aortic insufficiency (PE -16.7; 95% CI -26.4, -7.0) added independent predictive information. Explanatory power (r2) for models using clinical and demographic variables was .27 and increased after inclusion of echocardiographic data to an r2 of .35. Results in the subset of patients (n = 148) with acute coronary syndromes such as unstable angina or myocardial infarction were qualitatively similar. Selected factors (rales on examination, electrocardiographic changes suggestive of ischemia, and moderate to severe mitral regurgitation) also predicted which patients would die or have a decline in their functional status. In multivariate analysis, only rales remained an independent predictor of poor outcome (odds ratio 2.4; 95% CI 1.2, 4.5).

CONCLUSIONS

Echocardiographic data are correlated with measures of functional status in patients with chest pain, but the ability to predict future functional status from clinical or echocardiographic information is limited. Because functional status cannot be predicted adequately from either patients' characteristics or echocardiographic testing, it must be assessed directly.

Impact of valvular regurgitation and ventricular dysfunction on long-term survival in patients with chest pain

Doppler echocardiography is often used in evaluating patients with chest pain, but information on prognostic value of this testing and data to help guide selective use are limited. We prospectively studied 448 patients admitted from the emergency department for acute chest pain to assess the utility of qualitative echocardiographic data in predicting long-term survival and the incremental value of this information over routine clinical and electrocardiographic data. Doppler echocardiograms, recorded an average of 21 hours after presentation, were analyzed independently by 2 echocardiographers for global left and right ventricular function and valvular disease. Regional function was assessed by wall motion index. Data on long-term survival were collected with an average follow-up of 35.0 +/- 12.1 months. In univariate Cox regression analysis, left ventricular function and size, wall motion index, right ventricular function, and aortic, mitral, and tricuspid insufficiency were significant predictors of total and cardiovascular mortality. In multivariate analysis, moderate or severe left ventricular dysfunction (mortality rate ratio 3.2, 95% confidence intervals 1.8 to 5.8] and more than mild valvular regurgitation (mortality rate ratio 2.0, 95% confidence interval 1.1 to 3.6) were independent predictors of mortality in a model adjusted for clinical and electrocardiographic data. These factors were more common in patients aged >60 years, in those with prior acute myocardial infarction or angina, and in those with rales on physical examination. In the absence of these clinical characteristics, only 8 of 124 patients (7%) had moderate or severe left ventricular dysfunction or valvular regurgitation. In patients with moderate or severe regurgitation, a murmur was noted on the admission physical examination in 41 of 69 cases (59%). We conclude that echocardiographic evidence of moderate or severe left ventricular dysfunction or valvular regurgitation identifies a high-risk group for overall and cardiovascular mortality in patients with chest pain, and this evidence may not be detected clinically.

Serial creatine kinase-MB results are a sensitive indicator of acute myocardial infarction in chest pain patients with nondiagnostic electrocardiograms: the second Emergency Medicine Cardiac Research Group Study

OBJECTIVE

To determine the test performance characteristics of serial creatine kinase-MB (CK-MB) mass measurements for acute myocardial infarction (MI) in patients presenting to the ED with chest pain and nondiagnostic ECGs.

METHODS

A prospective, observational test performance study was conducted. Hemodynamically stable patients aged > or = 25 years with chest discomfort, but without ECGs diagnostic for MI, were enrolled at 7 university teaching hospitals. Presenting ECGs showing > 1-mV ST-segment elevation in > or = 2 electrically contiguous leads were considered diagnostic for MI; patients with diagnostic ECGs on presentation were excluded. Real-time, serial CK-MB mass levels were obtained using a rapid serum immunochemical assay at the time of ED presentation (0-hour) and 3 hours later (3-hour). The following testing schemes were evaluated for their sensitivity and specificity for detection of MI during patient evaluation in the ED: 1) an elevated (> or = 8 ng/mL) presenting CK-MB level; 2) an elevated presenting and/or 3-hour CK-MB level; 3) a significant increase (i.e., > or = 3 ng/mL) within the range of normal limits for CK-MB concentrations during the 3-hour period (delta CK-MB); and/or 4) development of ST-segment elevation during the 3 hours (second ECG).

RESULTS

Of the 1,042 patients enrolled, 777 (74.6%) were hospitalized, including all 67 MI patients (8.6% of admissions). As a function of duration of time in the ED, the test performance characteristics of serial CK-MBs for MI (and cumulative data for the additional ECG) were: [table: see text] The 0-hour to 3-hour CK-MB positive and negative predictive values were 52% to 55% and 96% to 99%, respectively. The sensitivities of serial CK-MB results as a function of the interval following chest discomfort onset were: [table: see text]

CONCLUSION

Serial CK-MB monoclonal antibody mass measurements in the ED can identify MI patients with initially nondiagnostic ECGs. CK-MB sensitivity significantly increases over 3 hours of observation of stable chest discomfort patients in the ED; it also increases as a function of the total interval from onset until enzyme measurement.

Responding to symptoms and signs of acute myocardial infarction--how do you educate the public?: a social-psychologic approach to intervention

In an era of highly time-dependent therapies for acute myocardial infarction-namely thrombolytic therapy and cardiopulmonary resuscitation-it is imperative that public education programs facilitate expeditious care-seeking. However, community intervention studies to reduce the interval of time-from the onset of an acute myocardial infarction to arrival at a hospital emergency department-have shown ambiguous results. To understand and reduce this time interval, a theoretic model is proposed that draws from self-regulation theory. The combined model focuses on three issues: first, information for systematic sign-and-symptom recognition and labeling; second, behavioral information as to what to do in the event of an acute myocardial infarction; and third, information on how to control affective and emotional responses that may interfere with effective coping. Seven recommendations are made for guiding community intervention with use of the proposed model.

Echocardiographic prediction of complications in patients with chest pain

The optimal role of Doppler echocardiography in the evaluation of patients with acute chest pain syndromes is unclear. We prospectively studied a cohort of 466 patients admitted with acute chest pain syndromes to clarify the relation between echocardiographic data and the risk of serious predischarge complications, and to determine if echocardiographic data can provide incremental prognostic information beyond clinical and electrocardiographic variables. Doppler echocardiograms, performed an average of 21 hours after presentation, were independently analyzed by 2 echocardiographers for information on global left and right ventricular function and valvular disease. Regional function was assessed by a wall motion index (WMI). A composite complications end point was positive if significant recurrent myocardial ischemia, heart failure, or arrhythmia developed after the echocardiogram. In univariate analysis, left (odds ratio [OR] 2.9, 95% confidence interval [CI] 1.6, 5.1) and right (OR 2.7, 95% CI 1.2, 6.2) ventricular function, left ventricular end-diastolic (OR 1.6/cm, 95% CI 1.1, 2.3) and end-systolic (OR 1.4/cm, 95% CI 1.1, 1.9) dimensions, and WMI (OR 3.0, 95% CI 1.8, 4.8) predicted complications that developed after the echocardiogram. In multivariate analysis, WMI remained an incremental predictor of risk with an OR of 2.2/unit (95% CI 1.2, 3.9) scaled from 1 to 4. Even in the subset of 403 patients without acute myocardial infarction, WMI was associated with an OR of 1.9 (95% CI 1.0, 3.7). We conclude that early echocardiography provides incremental prognostic information concerning risk of subsequent complications in patients hospitalized with chest pain.

Improvement of ED prediction of cardiac mortality among patients with symptoms suggestive of acute myocardial infarction

A study was undertaken to evaluate the 1-year risk of cardiac death for patients with chest pain/suspected acute myocardial infarction in the emergency department (ED) and express the prognosis in a statistical model. Clinical variables and electrocardiogram were correlated to cardiac death during 1 year. Cox regression model was used to estimate the risk of death as a continuous function of a risk score and the time interval. From these, the prognosis for each patient can be calculated. There were 6,794 visits by 5,303 patients followed for 1 year, during which 604 patients died. The absolute risk of cardiac death can be calculated from the independent predictors for cardiac death: age; sex; histories of diabetes mellitus, hypertension, and congestive heart failure; and symptoms, electrocardiographic pattern, and degree of suspicion of acute myocardial infarction on admission. This model allows estimation of the prognosis for every patient with chest pain/suspected acute myocardial infarction from data easily available in the ED.

Cost-effectiveness of a coronary care unit versus an intermediate care unit for emergency department patients with chest pain

BACKGROUND

Guidelines are not available for which patients with acute chest pain should be admitted to the coronary care unit and which patients can be reasonably triaged to monitored beds in lower levels of care.

METHODS AND RESULTS

Clinical and resource utilization data from 12 139 emergency department patients with acute chest pain were used in a decision-analytic model to identify cost-effective guidelines for the admission to a coronary care unit versus an intermediate care unit for initially uncomplicated patients without other indications for intensive care. The probability of clinical complications and death were derived from data on age-specific subsets of the population. Resource utilization estimates were based on cost data from a subset of 901 patients and length of stay data for the entire cohort. The survival benefit associated with initial triage to the coronary care unit instead of an intermediate care unit was assumed to be 15%. In the baseline analysis for 55- to 64-year-old patients, the probability of acute myocardial infarction (AMI) at which the coronary care unit had an incremental cost-effectiveness below $50 000 per year-of-life-saved was 29%. Triage to the coronary care unit was somewhat more cost-effective in elderly patients because their higher early complication rate more than offset their shorter life expectancy.

CONCLUSIONS

This analysis indicates that the coronary care unit usually should be reserved for patients with a moderate (21% or more, depending on the patient's age) probability of AMI unless patients need intensive care for other reasons. Clinical data suggest that only patients with ECG changes of ischemia or infarction not known to be old have a probability of AMI this high. Intermediate care units are appropriate for patients whose risks are not high enough for a coronary care unit to be cost-effective but too high for other alternatives to be recommended for safety and effectiveness.

Influence of pseudodiagnostic information on the evaluation of ischemic heart disease

STUDY OBJECTIVES

To measure the influence of classic epidemiologic risk factors (as recorded on the chart) on physicians' admission decisionmaking for patients with suspected acute cardiac ischemia and to compare the influence of those risk factors, which are of limited predictive utility, to the influence of predictively useful information.

DESIGN

Retrospective chart review.

SETTING

Emergency departments of two community hospitals.

PARTICIPANTS

Seven hundred eighty-seven patients evaluated for suspected acute cardiac ischemia, whether admitted or not.

RESULTS

Logistic regression revealed that the effect of a recorded history of hypertension on the admission decision (OR, 7.89; 95% CI, 4.57 to 13.58) was greater than that for ST-segment changes on the ECG (OR, 3.98; 95% CI, 2.56 to 6.18) or history of infarction (OR, 2.36; 95% CI, 1.53 to 3.62). A recorded history of diabetes had a small effect (OR, 1.84; 95% CI, 1.01 to 3.36), whereas Q waves and T-wave changes were not statistically significant.

CONCLUSION

Physicians' admission decisions appeared to be more heavily influenced by pseudodiagnostic information than by information of objective predictive power. Physicians do not appear to distinguish risk factors from diagnostic information; education may be directed at this distinction.

Prognosis and gender differences in chest pain patients discharged from an ED

A large proportion of patients evaluated for chest pain in the emergency department (ED) will be sent home because the probability of acute myocardial infarction, unstable angina, or other severe disease processes is determined to be sufficiently low. Patients who came to the ED at Sahlgrenska Hospital, Göteborg during a 21-month period because of chest pain were registered and followed up for one year. Survivors after one year were asked to complete a mailed questionnaire regarding different kinds of symptoms. Of 5,362 patients evaluated in the ED, 2,175 were sent home on their first visit. Fifty-four percent were men and 46% were women. The one-year mortality rate was 3% in men and 3% in women. Recurrent chest pain, dyspnea, and psychological symptoms were more frequently reported by patients with known cardiac disease than by patients without cardiac disease. Female patients with and without cardiac disease reported significantly more frequent recurrent chest pain, dyspnea, and psychological and psychosomatic complaints than male patients with and without cardiac disease. These data suggest that there are specific gender differences between men and women who are discharged from the ED after being evaluated for chest pain. In particular, psychological gender differences may exist and need to be addressed when evaluating patients with chest pain.

Utility and safety of immediate exercise testing of low-risk patients admitted to the hospital for suspected acute myocardial infarction

More than 2 million patients are admitted to U.S. hospitals annually for clinical suspicion of acute myocardial infarction (AMI), and > 70% are found not to have had a cardiac event. This study evaluates the safety and efficacy of immediate exercise testing for patients admitted to the hospital for suspected AMI. Ninety-three nonconsecutive low-risk patients admitted to the hospital from the emergency department to rule out AMI underwent exercise treadmill testing using a modified Bruce protocol immediately on admission to the hospital (median time < 1 hour). Twelve patients had positive exercise electrocardiograms, 6 of whom had significant coronary narrowing by angiography. An uncomplicated non-Q-wave AMI was diagnosed in 1 patient. Fifty-nine patients had negative and 22 patients had nondiagnostic exercise electrocardiograms. Of these 81 patients, 44 were discharged immediately after exercise testing, 17 were discharged within 24 hours, and 20 were discharged after 24 hours of observation. There were no complications from exercise testing. There were 2 late noncardiac deaths and 1 late AMI. Thus, immediate exercise testing of low-risk patients with chest pain who are at sufficient risk to be designated for hospital admission is effective in further stratifying this group into those who can be safely discharged immediately and those who require hospitalization.

Echocardiographic correlates of survival in patients with chest pain

OBJECTIVES

This study sought to identify echocardiographic predictors of survival in patients with chest pain and to assess the utility of qualitative echocardiographic data in the prognostic stratification of this cohort.

BACKGROUND

The potential usefulness of echocardiographic data in prognostic stratification of patients with acute chest pain is unclear, in part because of the qualitative nature of routinely available echocardiographic readings.

METHODS

The study group comprised 513 patients who underwent transthoracic two-dimensional and Doppler echocardiography within 1 month of emergency department visits for acute chest pain. Clinical and electrocardiographic (ECG) data were recorded for these patients at the time of their initial evaluations, and echocardiographic data were subsequently obtained from the official hospital reports. Follow-up survival rate data were obtained from medical records or the Massachusetts Bureau of Vital Statistics.

RESULTS

A mean of 28.5 months after the index visit, 102 patients (20%) had died, including 58 (57%) for whom the primary cause of death was cardiovascular. In analysis of routinely available qualitative echocardiographic data, left ventricular size and function, the presence of regional wall motion abnormalities, mitral regurgitation and structural abnormalities of the mitral valve were significant univariate correlates of both overall mortality and death from cardiovascular causes. Severe left ventricular dysfunction (adjusted rate ratio 3.8, 95% confidence interval [CI] 1.9-7.5) and moderate or severe mitral regurgitation (adjusted rate ratio 2.4, 95% CI 1.5-3.7) were independent predictors of mortality in a multivariate Cox regression analysis that adjusted for clinical and ECG variables. Moderate or severe left ventricular dysfunction and mitral regurgitation were predictors of mortality in the subset of patients without acute myocardial infarction.

CONCLUSIONS

Qualitative echocardiographic reports of left ventricular dysfunction and mitral regurgitation were independent correlates of prognosis in patients with acute chest pain, including patients without acute myocardial infarction. Further data are needed to assess the generalizability of these findings and the implications for use of this diagnostic technology.

Prognosis and symptoms one year after discharge from the emergency department in patients with acute chest pain

BACKGROUND

A high proportion of patients admitted to a medical emergency department due to chest pain are directly sent home, since the initial suspicion of acute myocardial infarction (AMI) can be quickly ruled out.

AIM

To describe the outcome of such patients during 1 year of follow-up in terms of mortality, development of AMI, and especially severity of symptoms 1 year after discharge.

METHODS

All patients who during 21 months were admitted to the medical emergency department at Sahlgrenska Hospital, Göteborg, Sweden, due to chest pain, and who could be directly sent home, were prospectively followed up for 1 year. Their outcome was compared with patients who had chest pain and were hospitalized for AMI during the same time.

RESULTS

Patients with chest pain directly sent home (n = 2,102) had a median age of 52 years (age range, 16 to 96 years), and 54 percent were men. The mortality during 1 year was 3 percent, and 3 percent developed AMI. As compared with patients with AMI, those who were directly sent home less frequently reported various cardiovascular symptoms, with the exception for chest pain at rest and palpitations. On the other hand, various emotional and psychosomatic symptoms were more frequently reported by patients who were directly sent home than by patients with AMI.

CONCLUSION

Patients who came to a medical emergency department due to chest pain, and who were sent home, had a low risk of death and development of infarction during the following year. Survivors after 1 year do, however, more frequently report emotional and psychosomatic symptoms than survivors of AMI.