Evaluation of a Clinical Decision Rule for Young Adult Patients with Chest Pain

Pragmatic approach to chest pain patients discharged with undetectable high-sensitivity troponin T and normal electrocardiogram: the STABS + CT protocol

A strategy that discharges chest pain patients with negative high-sensitivity troponin and non-ischaemic electrocardiography changes may still result in 0.44% of patients experiencing myocardial infarction within 30 days. We observed that a pragmatic approach that systematically discharged 25 patients on cardio-protective medications of aspirin, metoprolol and atorvastatin followed with prompt (<10 days) coronary computed tomography angiography resulted in no major adverse cardiac event and adverse drug reaction 30 days post-presentation. The strategy resulted in three patients (12%) ultimately diagnosed with likely unstable angina, which required planned coronary intervention in two patients and medical management in one patient. No unplanned readmissions for chest pains were noted from initial presentation through to 6-month follow up.

Comparison of Time Trends of Cardiovascular Disease Risk Factors and Framingham Risk Score Between Patients With and Without Acute Coronary Syndrome Undergoing Percutaneous Intervention Over the Last 17 Years: From the Mayo Clinic Percutaneous Coronary Intervention Registry

BACKGROUND

The objective of this study was to investigate cardiovascular disease risk factor (cvRF) profiles and compare their trends over 17 years in patients with and without acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI).

HYPOTHESIS

Time trends of cvRF are different between ACS and non-ACS patients.

METHODS

This study was a time-trend analysis from 1994 to 2010 within the Mayo Clinic PCI registry. Outcome measures were incidence and prevalence of cvRF, including the Framingham Risk Score (FRS), at the time of admission for PCI.

RESULTS

Age of non-ACS patients was higher than that of ACS patients, and age distribution slightly shifted toward older age in both groups (P for trend <0.001). There was no difference in FRS between the 2 groups; however, 10-year cardiovascular disease risk (%) remained higher in non-ACS than in ACS patients, decreasing over time. Diastolic blood pressure and high-density lipoprotein cholesterol were higher in non-ACS patients, but total cholesterol and low-density lipoprotein cholesterol were higher in ACS patients, with an improving trend over time. Prevalence of diabetes mellitus, hypertension, and history of hypercholesterolemia were higher in non-ACS patients, increasing over time. Smoking did not change over time. Use of most medications increased over time in both groups.

CONCLUSIONS

Most cvRFs and their time trends exhibited statistically significant differences between ACS and non-ACS patients, except systolic blood pressure, body mass index, and history of myocardial infarction. A new risk-factor profile assessment may be needed for stratification of PCI patients according to ACS and non-ACS status. Clinical and public-health interventions should consider different approaches to ACS and non-ACS patients.

Diagnostic values of chest pain history, ECG, troponin and clinical gestalt in patients with chest pain and potential acute coronary syndrome assessed in the emergency department

In the assessment of chest pain patients with suspected acute coronary syndrome (ACS) in the emergency department (ED), physicians rely on global diagnostic impressions (‘gestalt’). The aim of this study was to determine the diagnostic value of the ED physician’s overall assessment of ACS likelihood, and the values of the main diagnostic modalities underlying this assessment, namely the chest pain history, the ECG and the initial troponin result. 1,151 consecutive ED chest pain patients were prospectively included. The ED physician’s interpretation of the chest pain history, the ECG, and the global likelihood of ACS were recorded on special forms. The discharge diagnoses were retrieved from the medical records. A chart review was carried out to determine whether patients with a non-ACS diagnosis at the index visit had ACS or suffered cardiac death within 30 days. The gestalt was better than its components both at ruling in (“Obvious ACS”, LR 29) and at ruling out (“No Suspicion of ACS”, LR 0.01) ACS. In the “Strong suspicion of ACS” group, 60% of the patients did not have ACS. A positive TnT (LR 24.9) and an ischemic ECG (LR 8.3) were strong predictors of ACS and seemed superior to pain history for ruling in ACS. In patients with a normal TnT and non-ischemic ECG, chest pain history typical of AMI was not a significant predictor of AMI (LR 1.9) while pain history typical of unstable angina (UA) was a moderate predictor of UA (LR 4.7). Clinical gestalt was better than its components both at ruling in and at ruling out ACS, but overestimated the likelihood of ACS when cases were assessed as strong suspicion of ACS. Among the components of the gestalt, TnT and ECG were superior to the chest pain history for ruling in ACS, while pain history was superior for ruling out ACS.

Impact of clinical predictors and routine coronary artery disease testing on outcome of patients admitted to chest pain decision unit

BACKGROUND

Chest pain decision unit (CDU) evaluation of patients with acute chest pain (ACP) and nondiagnostic electrocardiogram (ECG) usually includes noninvasive testing for coronary artery disease (CAD).

HYPOTHESIS

CAD evaluation will not improve clinical outcome in low-risk ACP patients.

METHODS

We studied 459 adults admitted to CDU with ACP and no troponin release who underwent noninvasive CAD testing (stress testing in 396 and coronary computed tomographic angiography in 63). Multivariate logistic regression was used to determine predictors of adverse outcome over a 3-year follow-up period.

RESULTS

Initial noninvasive test was normal in 367 (80%) and abnormal (positive or indeterminate) in 92 (20%). A total of 42 (9%) patients underwent invasive coronary angiography, and 16 (3.5%) underwent revascularization. During follow-up, 33 patients had a total of 36 major clinical events: 12 revascularizations, 9 myocardial infarctions, and 15 deaths. Multivariate logistic regression analysis identified abnormal ECG (odds ratio [OR]: 2.7, P = 0.03), typical chest pain (OR: 3.8, P = 0.002), diabetes (OR: 4.1, P = 0.001), and known CAD (OR: 2.3, P = 0.03) as independent predictors for adverse outcome, but not noninvasive test result. Thus, in 187 patients with no high-risk features (41% of the cohort), the annualized event rate was 0.5%. In 272 patients with at least 1 high-risk feature, annualized event rates were 2.8% and 5.7% when noninvasive test was normal or abnormal, respectively (P = 0.04).

CONCLUSIONS

Clinical risk stratification allows identification of patients at low risk of adverse outcome over an intermediate period of follow-up. Noninvasive testing is not warranted in such patients.

Validation of the Vancouver Chest Pain Rule: a prospective cohort study

OBJECTIVES

The objective was to validate the Vancouver Chest Pain Rule in an emergency department (ED) setting to identify very-low-risk patients with acute chest pain.

METHODS

A prospective cohort study was conducted on consecutive patients 25 years of age and older presenting to the ED with a chief complaint of acute chest pain during January 2009 to July 2009. According to the Vancouver Chest Pain Rule, cardiac history, chest pain characteristics, physical and electrocardiogram (ECG) findings, and cardiac biomarker measurement (creatine kinase-myocardial band isoenzyme [CK-MB]) were used to identify patients with very low risk for developing acute coronary syndrome (ACS) in 30 days. The primary outcome was defined as developing ACS (myocardial infarction or non-ST-elevation myocardial infarction [MI]/unstable angina) within 30 days of ED presentation, and all diagnoses were made using predefined explicit criteria. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated.

RESULTS

Of 593 patients who were eligible for evaluation, 39 (6.6%) developed MI and 43 (7.3%) developed unstable angina. Among all patients, 292 (49.2%) patients could have been assigned to the very-low-risk group and discharged after a brief ED assessment according to the Vancouver Chest Pain Rule. Among these patients, four (1.4%) developed ACS within 30 days. Sensitivity of the rule was 95.1% (95% confidence interval [CI]=88.0% to 98.7%), specificity was 56.3% (95% CI=52.0% to 60.7%), positive prediction value was 25.9% (95% CI=21.0% to 31.0%), and negative prediction value was 98.6% (95% CI=96.5% to 99.6%).

CONCLUSIONS

This study showed a lower sensitivity and higher specificity when applying the Vancouver Chest Pain Rule to this population as compared to the original study.

Utility of observation units for young emergency department chest pain patients

BACKGROUND

Determining which patients presenting to the Emergency Department (ED) require further work-up for acute coronary syndrome (ACS) can be difficult. The utility of routine observation for cardiac testing in low-risk young adult patients has been questioned.

STUDY OBJECTIVES

We investigated the rate of positive findings yielded by routine cardiac observation unit work-up in patients aged 40 years or younger.

METHODS

This was a retrospective observational cohort study of patients aged 18-40 years who were evaluated for ACS in an ED-based observation unit. Data were collected by trained abstractors from electronic medical records.

RESULTS

A total of 362 patients met inclusion criteria. Of those, 239 received stress testing, yielding five positive and nine indeterminate results. One other patient had acute troponin elevation while under observation. The positive stress test patients and troponin-elevated patient underwent cardiac angiography. Only one positive stress test patient showed significant coronary stenosis and received coronary interventions. In follow-up data, one patient had an adverse cardiac outcome within 1 year of index visit, but no coronary interventions. Thus, only 3 patients had adverse cardiac events, with only one patient warranting intervention discovered by observation unit stress testing and a second via serial cardiac markers.

CONCLUSION

Routine observation of symptomatic young adults for ACS had low yield. Observation identified one patient with acute cardiac marker elevation and further stress testing identified only one patient with intervenable ACS, despite a high false-positive rate. This suggests that observation and stress testing should not be routinely performed in this demographic absent other high-risk features.

Cholesteryl esters associated with acyl-CoA:cholesterol acyltransferase predict coronary artery disease in patients with symptoms of acute coronary syndrome

OBJECTIVES

Identifying the likelihood of a patient having coronary artery disease (CAD) at the time of emergency department (ED) presentation with chest pain could reduce the need for stress testing or coronary imaging after myocardial infarction (MI) has been excluded. The authors aimed to determine if a novel cardiac biomarker consisting of plasma cholesteryl ester (CE) levels typically derived from the activity of the enzyme acyl-CoA:cholesterol acyltransferase (ACAT2) are predictive of CAD in a clinical model.

METHODS

A single-center prospective cohort design enrolled participants with symptoms of acute coronary syndrome (ACS) undergoing coronary computed tomography angiography (CCTA) or invasive angiography. Plasma samples were analyzed for CE composition with mass spectrometry. The primary endpoint was any CAD determined at angiography. Multivariable logistic regression analyses were used to estimate the relationship between the sum of the plasma concentrations from cholesteryl palmitoleate (16:1) and cholesteryl oleate (18:1) (defined as ACAT2-CE) and the presence of CAD. The added value of ACAT2-CE to the model was analyzed comparing the C-statistics and integrated discrimination improvement (IDI).

RESULTS

The study cohort was composed of 113 participants with a mean (± standard deviation [SD]) age of 49 (±11.7) years, 59% had CAD at angiography, and 23% had an MI within 30 days. The median (interquartile range [IQR]) plasma concentration of ACAT2-CE was 938 μmol/L (IQR = 758 to 1,099 μmol/L) in patients with CAD and 824 μmol/L (IQR = 683 to 998 μmol/L) in patients without CAD (p = 0.03). When considered with age, sex, and the number of conventional CAD risk factors, ACAT2-CE levels were associated with a 6.5% increased odds of having CAD per 10 μmol/L increase in concentration. The addition of ACAT2-CE significantly improved the C-statistic (0.89 vs. 0.95, p = 0.0035) and IDI (0.15, p < 0.001) compared to the reduced model. In the subgroup of low-risk observation unit patients, the CE model had superior discrimination compared to the Diamond-Forrester classification (IDI = 0.403, p < 0.001).

CONCLUSIONS

Plasma levels of ACAT2-CE have strong potential to predict a patient's likelihood of having CAD when considered in a clinical model but not when used alone. In turn, a clinical model containing ACAT2-CE could reduce the need for cardiac imaging after the exclusion of MI.

High-risk chief complaints I: chest pain--the big three

Chest pain is one of the most frequently seen chief complaints in patients presenting to emergency departments, and is considered to be a "high-risk" chief complaint. The differential diagnosis for chest pain is broad, and potential causes range from the benign to the immediately life-threatening. Although many (if not most) emergency department patients with chest pain do not have an immediately life-threatening condition, correct diagnoses can be difficult to make, incorrect diagnoses may lead to catastrophic therapies, and failure to make a timely diagnosis may contribute to significant morbidity and mortality. Several atraumatic "high-risk" causes of chest pain are discussed in this article, including myocardial infarction and ischemia, thoracic aortic dissection, and pulmonary embolism. Also included are brief discussions of tension pneumothorax, esophageal perforation, and cardiac tamponade.

The Influence of a Physician's Use of a Diagnostic Decision Aid on the Malpractice Verdicts of Mock Jurors

Background . One reason why physicians may be reluctant to use diagnostic decision aids is that such usage might increase the likelihood of an unfavorable malpractice verdict. The authors tested this hypothesis by sending a DVD of a malpractice trial to a national sample of jury-eligible adults. Methods. There were 3 independent variables: 1) the physician did or did not use a diagnostic aid, 2) the patient's symptoms either were or were not consistent with a diagnosis of probable appendicitis, and 3) the physician's decision to operate or not operate was either concordant or discordant with the severity of the patient's symptoms. Jurors rendered a verdict, and if they deemed the physician not to have met the standard of care, they indicated how punitive they felt toward the physician. Results . Mock jurors were more likely to side with the physician-defendant if he recommended an operation when there were many symptoms and refrained when there were few symptoms compared with a physician who did the converse. The use of a decision aid had no influence on this binary standard-of-care decision. Among those physicians deemed liable by the jurors, defying the aid resulted in heightened punishment compared with heeding it. Conclusion . Contrary to many physicians' fears, use of a diagnostic decision aid did not influence the likelihood of an adverse malpractice verdict. Complying with the aid's recommendation provided a measure of protection against jurors' punitiveness for those physicians deemed liable for malpractice.

A study to derive a clinical decision rule for triage of emergency department patients with chest pain: design and methodology

BACKGROUND

Chest pain is the second most common chief complaint in North American emergency departments. Data from the U.S. suggest that 2.1% of patients with acute myocardial infarction and 2.3% of patients with unstable angina are misdiagnosed, with slightly higher rates reported in a recent Canadian study (4.6% and 6.4%, respectively). Information obtained from the history, 12-lead ECG, and a single set of cardiac enzymes is unable to identify patients who are safe for early discharge with sufficient sensitivity. The 2007 ACC/AHA guidelines for UA/NSTEMI do not identify patients at low risk for adverse cardiac events who can be safely discharged without provocative testing. As a result large numbers of low risk patients are triaged to chest pain observation units and undergo provocative testing, at significant cost to the healthcare system. Clinical decision rules use clinical findings (history, physical exam, test results) to suggest a diagnostic or therapeutic course of action. Currently no methodologically robust clinical decision rule identifies patients safe for early discharge.

METHODS/DESIGN

The goal of this study is to derive a clinical decision rule which will allow emergency physicians to accurately identify patients with chest pain who are safe for early discharge. The study will utilize a prospective cohort design. Standardized clinical variables will be collected on all patients at least 25 years of age complaining of chest pain prior to provocative testing. Variables strongly associated with the composite outcome acute myocardial infarction, revascularization, or death will be further analyzed with multivariable analysis to derive the clinical rule. Specific aims are to: i) apply standardized clinical assessments to patients with chest pain, incorporating results of early cardiac testing; ii) determine the inter-observer reliability of the clinical information; iii) determine the statistical association between the clinical findings and the composite outcome; and iv) use multivariable analysis to derive a highly sensitive clinical decision rule to guide triage decisions.

DISCUSSION

The study will derive a highly sensitive clinical decision rule to identify low risk patients safe for early discharge. This will improve patient care, lower healthcare costs, and enhance flow in our busy and overcrowded emergency departments.

Validation of the Acute Heart Failure Index

STUDY OBJECTIVE

Validate a clinical prediction rule prognostic of short-term fatal and inpatient nonfatal outcomes for heart failure patients admitted through the emergency department.

METHODS

We retrospectively studied a random cohort of 8,384 adult patients admitted to Pennsylvania hospitals in 2003 and 2004 with a diagnosis of heart failure as defined by primary discharge diagnosis codes. We reported the proportions of inpatient death, serious medical complications before discharge, and 30-day death in the patients identified as low risk by the prediction rule.

RESULTS

The prediction rule classified 1,609 (19.2%) of the patients as low risk. Within this subgroup, there were 12 (0.7%; 95% confidence interval [CI] 0.3% to 1.2%) inpatient deaths, 28 (1.7%; 95% CI 1.1% to 2.4%) patients survived to hospital discharge after a serious complication, and 47 (2.9%; 95% CI 2.1% to 3.7%) patients died within 30 days of the index hospitalization.

CONCLUSION

This prediction rule identifies a group of admitted heart failure patients at low risk of inpatient mortal and nonmortal complications. Our validation findings suggest the rule could assist physicians in making site-of-care decisions for this patient population and aid in analyzing presenting illness burden in study populations.

ST2 in emergency department chest pain patients with potential acute coronary syndromes

STUDY OBJECTIVE

The emergency department (ED) evaluation of potential acute coronary syndrome patients is limited by the initial sensitivity of cell injury biochemical markers. Increased ST2, a protein thought to participate in the response to cardiovascular injury, has been noted to be prognostic in patients with acute myocardial infarction. We hypothesize that ST2 would be increased at presentation in ED chest pain patients with myocardial ischemia, thus allowing for the early identification of acute myocardial infarction, acute coronary syndrome, and 30-day adverse cardiovascular events, with an area under the receiver operator characteristic curve (AUC) for each outcome of greater than 0.7.

METHODS

Patients aged 25 years or older and presenting to the ED with chest pain prompting an ECG were prospectively enrolled. ST2 was measured at presentation. Main outcomes were acute myocardial infarction, acute coronary syndrome, and 30-day events (death, acute myocardial infarction, or revascularization). Median ST2 values were calculated for patients with and without each outcome. The AUCs were calculated for each outcome. In a post hoc analysis, patients with outlying increased ST2 values were examined to determine possible alternative causes for ST2 expression.

RESULTS

There were 348 patients enrolled. The outcomes were acute myocardial infarction 17 patients (4.9%), acute coronary syndrome 39 (11.2%), and 30-day events 23 (6.6%). The AUCs for acute myocardial infarction, acute coronary syndrome, and 30-day events were 0.636, 0.630, and 0.579, respectively. ST2 did not predict acute myocardial infarction, acute coronary syndrome, or 30-day events. It was increased in a small number of patients with pulmonary disease, notably, pulmonary emboli, systemic infection or inflammation, and alcohol abuse.

CONCLUSION

ST2 was not of value in the evaluation of ED patients with potential acute coronary syndrome.

The role of cardiac risk factor burden in diagnosing acute coronary syndromes in the emergency department setting

STUDY OBJECTIVE

We seek to determine whether cardiac risk factor burden (defined as the number of conventional cardiac risk factors present) is useful for the diagnosis of acute coronary syndromes in the emergency department (ED) setting.

METHODS

This was a post hoc analysis of the Internet Tracking Registry of Acute Coronary Syndromes (i*trACS) registry, which had 17,713 ED visits for suspected acute coronary syndromes. First visit for US patients who were not cocaine or amphetamine users, who did not leave against medical advice, and for whom ECG and demographic data were complete were included. Acute coronary syndrome was defined by 30-day revascularization, diagnostic-related group codes, or death within 30 days, with positive cardiac biomarkers at index hospitalization. Cardiac risk factors were diabetes, hypertension, smoking, hypercholesterolemia, and family history of coronary artery disease. Cardiac risk factor burden was defined as the number of risk factors present. Because multiple logistic regression analysis revealed that age modified the relationship between cardiac risk factor burden and acute coronary syndromes, a stratified analysis was performed for 3 age categories: younger than 40, 40 to 65, and older than 65 years. Positive likelihood ratios and negative likelihood ratios with their 95% confidence intervals (CIs) were calculated for each total risk factor cutoff.

RESULTS

Of 10,806 eligible patients, 871 (8.1%) had acute coronary syndromes. In patients younger than 40 years, having no risk factors had a negative likelihood ratio of 0.17 (95% CI 0.04 to 0.66), and having 4 or more risk factors had a positive likelihood ratio of 7.39 (95% CI 3.09 to 17.67). In patients between 40 and 65 years of age, having no risk factors had a negative likelihood ratio of 0.53 (95% CI 0.40 to 0.71), and having 4 or more risk factors had a positive likelihood ratio of 2.13 (95% CI 1.66 to 2.73). In patients older than 65 years, having no risk factors had a negative likelihood ratio of 0.96 (95% CI 0.74 to 1.23), and having 4 or more risk factors had a positive likelihood ratio of 1.09 (95% CI 0.64 to 1.62).

CONCLUSION

Cardiac risk factor burden has limited clinical value in diagnosing acute coronary syndromes in the ED setting, especially in patients older than 40 years.

Prospective multicenter study of quantitative pretest probability assessment to exclude acute coronary syndrome for patients evaluated in emergency department chest pain units

STUDY OBJECTIVE

We compare the diagnostic accuracy of 3 methods--attribute matching, physician's written unstructured estimate, and a logistic regression formula (Acute Coronary Insufficiency-Time Insensitive Predictive Instrument, ACI-TIPI)--of estimating a very low pretest probability (< or = 2%) for acute coronary syndromes in emergency department (ED) patients evaluated in chest pain units.

METHODS

We prospectively studied 1,114 consecutive patients from 3 academic EDs, evaluated for acute coronary syndrome. Physicians collected data required for pretest probability assessment before protocol-driven chest pain unit testing. A pretest probability greater than 2% was considered "test positive." The criterion standard was the outcome of acute coronary syndrome (death, myocardial infarction, revascularization, or > 60% stenosis prompting new treatment) within 45 days, adjudicated by 3 independent reviewers.

RESULTS

Fifty-one of 1,114 enrolled patients (4.5%; 95% confidence interval [CI] 3.4% to 6.0%) developed acute coronary syndrome within 45 days, including 4 of 991 (0.4%; 95% CI 0.1% to 1.0%) patients, discharged after a negative chest pain unit evaluation result, who developed acute coronary syndrome. Unstructured estimate identified 293 patients with pretest probability less than or equal to 2%, 2 had acute coronary syndrome, yielding sensitivity of 96.1% (95% CI 86.5% to 99.5%) and specificity of 27.4% (95% CI 24.7% to 30.2%). Attribute matching identified 304 patients with pretest probability less than or equal to 2%; 1 had acute coronary syndrome, yielding a sensitivity of 98.0% (95% CI 89.6% to 99.9%) and a specificity of 26.1% (95% CI 23.6% to 28.7%). ACI-TIPI identified 56 patients; none had acute coronary syndrome, yielding sensitivity of 100% (95% CI 93.0% to 100%) and specificity of 6.1% (95% CI 4.7% to 7.9%).

CONCLUSION

In a low-risk ED population with symptoms suggestive of acute coronary syndrome, patients with a quantitative pretest probability less than or equal to 2%, determined by attribute matching, unstructured estimate, or logistic regression, may not require additional diagnostic testing.