Risk stratification of patients with acute chest pain and normal troponin concentrations

Effective combination of isolated symptom variables to help stratifying acute undifferentiated chest pain in the emergency department

BACKGROUND

Symptom is still indispensable for the stratification of chest pain in the emergency department. However, it is a sophisticated aggregation of several aspects of characteristics and effective combination of those variables remains deficient. We aimed to develop and validate a chest pain symptom score (CPSS) to address this issue.

HYPOTHESIS

The CPSS may help stratifying acute undifferentiated chest pain in ED.

METHODS

Patients with non-ST segment elevation chest pain and negative cardiac troponin (cTn) over 3 hours after symptom onset were consecutively recruited as the derivation cohort. Logistic regression analyses identified statistical predictors from all symptom aspects for 30-day acute myocardial infarction (AMI) or death. The performance of CPSS was compared with the symptom classification methods of the history variable in the history, electrocardiograph, age, risk factors, troponin (HEART) score. This new model was validated in a separated cohort of patients with negative cTn within 3 hours.

RESULTS

Seven predictors in four aspects of chest pain symptom were identified. The CPSS was an independent predictor for 30-day AMI or death (P < 0.001). In the derivation (n = 1434) and validation (n = 976) cohorts, the expected and observed event rates were well calibrated (Hosmer-Lemeshow test P > 0.30), and the c-statistics of CPSS were 0.72 and 0.73, separately, significantly better than the previous history classifications in HEART score (P < 0.001). Replacing the history variable with the CPSS improved the discrimination and risk classification of HEART score significantly (P < 0.001).

CONCLUSIONS

The effective combination of isolated variables was meaningful to make the most stratification value of symptoms. This model should be considered as part of a comprehensive strategy for chest pain triage.

Risk stratification for coronary artery disease in multi-ethnic populations: Are there broader considerations for cost efficiency?

Coronary artery disease (CAD) screening and diagnosis are core cardiac specialty services. From symptoms, autopsy correlations supported reductions in coronary blood flow and dynamic epicardial and microcirculatory coronaries artery disease as etiologies. While angina remains a clinical diagnosis, most cases require correlation with a diagnostic modality. At the onset of the evidence building process much research, now factored into guidelines were conducted among population and demographics that were homogenous and often prior to newer technologies being available. Today we see a more diverse multi-ethnic population whose characteristics and risks may not consistently match the populations from which guideline evidence is derived. While it would seem very unlikely that for the majority, scientific arguments against guidelines would differ, however from a translational perspective, there will be populations who differ and importantly there are cost-efficacy questions, e.g., the most suitable first-line tests or what parameters equate to an adequate test. This article reviews non-invasive diagnosis of CAD within the context of multi-ethnic patient populations.

Long-term prognostic value of peak exercise echocardiogram in patients hospitalized with acute chest pain

INTRODUCTION

Peak exercise echocardiogram (EEcho) has shown reasonable sensitivity and specificity in detecting significant coronary artery disease (CAD). The objective was to evaluate the prognostic value of EEcho in patients hospitalized for acute chest pain (CP) and its additional prognostic information regarding exercise electrocardiogram test (EECG).

METHODS

Prospective observational study performed between May 2011 and September 2013, including 250 patients consecutively admitted for acute CP with normal cardiac biomarkers and nondiagnostic electrocardiogram. All patients were prospectively followed for 1 year, and major adverse cardiovascular events (MACE) were recorded: cardiac death, nonfatal myocardial infarction (MI), or angina with coronary revascularization.

RESULTS

EEcho was positive in 16%. Patients with positive EEcho had a higher incidence of hypertension and higher TIMI risk score, showing significant CAD in 66%. We observed contradictory results (EECG-EEcho) in 20%. Patients with positive EEcho and negative EECG had significant CAD in the 66%, and patients undergoing coronary angiography with negative EEcho and positive EECG did not show significant coronary artery disease. Only positive EEcho (P<.001, HR 0.169; 95% CI, 0.088-0.250) and atrial fibrillation (P<.025, HR 0.125; 95% CI, 0.016-0.233) were independently associated with MACE during follow-up. In patients with negative EEcho, the presence of MACE was 2%.

CONCLUSIONS

EEcho in patients hospitalized for acute chest pain presents good ability to diagnose acute coronary syndrome, while providing additional information when combined with an EECG in up to 20% of cases. Moreover, a negative EEcho in this cohort seems to provide prognostic information beyond the acute event to predict long-term MACE.

A clinical score to obviate the need for cardiac stress testing in patients with acute chest pain and negative troponins

INTRODUCTION

Although cardiac stress testing may help establish the safety of early discharge in patients with suspected acute coronary syndromes and negative troponins, more cost-effective strategies are necessary. We aimed to develop a clinical prediction rule to safely obviate the need for cardiac stress testing in this setting.

METHODS

A decision rule was derived in a prospective cohort of 3001 patients with acute chest pain and negative troponins, and validated in a set of 1473 subjects. The primary end point was a composite of positive cardiac stress testing (in the absence of a subsequent negative coronary angiogram), positive coronary angiography, or any major coronary events within 3 months.

RESULTS

A score chart was built based on 7 variables: male sex (+2), age (+1 per decade from the fifth decade), diabetes mellitus (+2), hypercholesterolemia (+1), prior coronary revascularization (+2), type of chest pain (typical angina, +5; non-specific chest pain, -3), and non-diagnostic repolarization abnormalities (+2). In the validation set, the model showed good discrimination (c statistic = 0.84; 95% confidence interval, 0.82-0.87) and calibration (Hosmer-Lemeshow goodness-of-fit test, P= .34). If stress tests were avoided in patients in the validation sample with a sum score of 0 or lower, the number of referrals would be reduced by 23.4%, yielding a negative predictive value of 98.8% (95% confidence interval, 97.0%-99.7%).

CONCLUSION

This novel prediction rule based on a combination of readily available clinical characteristics may be a valuable tool to decide whether stress testing can be reliably avoided in patients with acute chest pain and negative troponins.

Ultra-Sensitive Copeptin and Cardiac Troponin in Diagnosing Non-ST-Segment Elevation Acute Coronary Syndromes--The COPACS Study

OBJECTIVES

We tested the noninferiority of a fast-track rule-out protocol for the diagnosis of non-ST-segment elevation myocardial infarction vs noncoronary chest pain based on the single-sampling combined assessment of medium-sensitivity cardiac troponin I and ultra-sensitive copeptin compared with the serial assessment of medium-sensitivity cardiac troponin I.

METHODS

Ultra-sensitive copeptin and medium-sensitivity cardiac troponin I levels were measured at presentation in 196 consecutive patients admitted to the emergency department for acute nontraumatic chest pain within 6 hours from symptoms onset and without ST-segment elevation on a 12-lead electrocardiogram. The diagnostic performance for non-ST-segment elevation myocardial infarction diagnosis of the dual-marker single-sampling strategy with medium-sensitivity cardiac troponin I and ultra-sensitive copeptin on admission was compared with that of the serial 0- and 3-hour medium-sensitivity cardiac troponin I sampling in reference to the adjudicated postdischarge diagnosis, using both the comparison of area under the curve (AUC) receiver operating characteristic and the McNemar chi-square test.

RESULTS

The diagnosis of non-ST-segment elevation myocardial infarction was adjudicated in 29 patients (14.8%). The combination of medium-sensitivity cardiac troponin I and ultra-sensitive copeptin generated an AUC of 0.87 (95% confidence interval, 0.82-0.91), which was noninferior with respect to the 3-hour interval medium-sensitivity cardiac troponin I serial sampling (P = .194 for AUC difference). The combination of medium-sensitivity cardiac troponin I and ultra-sensitive copeptin also yielded a numerically higher diagnostic sensitivity (100% vs 89.7%; P = not significant).

CONCLUSIONS

A single-sampling strategy of combined ultra-sensitive copeptin and medium-sensitivity cardiac troponin I is noninferior to a 0- and 3-hour serial medium-sensitivity cardiac troponin I sampling in ruling out non-ST-segment elevation myocardial infarction and thus may allow an earlier discharge of patients who are ruled out for non-ST-segment elevation myocardial infarction (ClinicalTrials.gov Identifier NCT01962506).

The diagnostic value of clinical symptoms in women and men presenting with chest pain at the emergency department, a prospective cohort study

Background

Previous studies suggested that diagnosing coronary artery disease (CAD) is more difficult in women than in men. Studies investigating the predictive value of clinical signs and symptoms and compare its combined diagnostic value between women and men are lacking.

Methodology

Data from a large multicenter prospective study was used. Patients admitted to the emergency department (ED) with chest pain but without ST-elevation were eligible. The endpoint was proven CAD, defined as a significant stenosis at angiography or the diagnosis of a non-ST-elevation myocardial infarction or cardiovascular death within six weeks after presentation at the ED. Twelve clinical symptoms and seven cardiovascular risk factors were collected. Potential predictors of CAD with a p-value <0.15 in the univariable analysis were included in a multivariable model. The diagnostic value of clinical symptoms and cardiovascular risk factors was quantified in women and men separately and areas under the curve (AUC) were compared between sexes.

Results

A total of 2433 patients were included. We excluded 102 patients (4%) with either an incomplete follow up or ST-elevation. Of the remaining 2331 patients 43% (1003) were women. CAD was present in 111 (11%) women and 278 (21%) men. In women 11 out of 12 and in men 10 out of 12 clinical symptoms were univariably associated with CAD. The AUC of symptoms alone was 0.74 (95%CI: 0.69-0.79) in women and 0.71 (95%CI: 0.68-0.75) in men and increased to respectively 0.79 (95%CI: 0.74-0.83) in women versus 0.75 (95%CI: 0.72-0.78) in men after adding cardiovascular risk factors. The AUCs of women and men were not significantly different (p-value symptoms alone: 0.45, after adding cardiovascular risk factors: 0.11).

Conclusion

The diagnostic value of clinical symptoms and cardiovascular risk factors for the diagnosis of CAD in chest pain patients presenting on the ED was high in women and men. No significant differences were found between sexes.

Alteration of HDL functionality and PON1 activities in acute coronary syndrome patients

OBJECTIVE

The functionality of HDL has been suggested as an important factor in the prevention of cardiovascular and coronary artery diseases. The objective of the present study was to investigate the functionality of HDL and the factors that may affect the anti-atherogenic properties of HDL in ACS patients.

METHODS AND RESULTS

One hundred healthy subjects and 205 ACS patients were recruited. HDL functionality was evaluated by measuring their capacity to mediate cholesterol efflux from J774 macrophages. Oxidative stress status was determined by measuring plasma malondialdehyde (MDA), protein carbonyl, and vitamin E levels by HPLC. The PON1 Q192R polymorphism status and PON1 paraoxonase and arylesterase activities of the healthy subjects and ACS patients were also determined. The HDL of ACS patients displayed a limited capacity to mediate cholesterol efflux, especially via the ABCA1-pathway. MDA (7.06±0.29 μM) and protein carbonyl (9.29±0.26 μM) levels were significantly higher in ACS patients than in healthy subjects (2.29±0.21 μM and 3.07±0.17 μM, respectively, p<0.0001), while α- and γ-tocopherol (vitamin E) levels in ACS patients were 8-fold (p<0.001) and 2-fold (p<0.05) lower than in healthy subjects. Paraoxonase, arylesterase and HDL-corrected PON1 activities (PON1 activity/HDL ratio) were significantly lower in ACS patients. Logistic regression analyses showed that high PON1 paraoxonase and arylesterase activities had a significant protective effect (OR=0.413, CI 0.289-0.590, p<0.001; OR=0.232 CI 0.107-0.499, p<0.001, respectively) even when adjusted for HDL level, age, BMI, and PON1 polymorphism.

CONCLUSION

The results of the present study showed that the functionality of HDL is impaired in ACS patients and that the impairment may be due to oxidative stress and an alteration of PON1 activities.

A meta-analysis and systematic review of computed tomography angiography as a diagnostic triage tool for patients with chest pain presenting to the emergency department

BACKGROUND

To assess clinical utility of computed tomography angiography (CTA) in the diagnosis of chest pain patients presenting to emergency departments (EDs), we conducted a meta-analysis of CTA in patients with suspected acute coronary syndromes (ACSs).

METHODS

386 studies were identified on initial review of literature. Inclusion criteria were: (1) prospective study with ≥1 month follow-up, (2) use of CTA in the ED setting, (3) use of ACC/AHA definitions for ACS and robust assessment of major adverse cardiac events, (4) ≥30 patients, and (5) study population with initial non-diagnostic ECGs and negative biomarkers.

RESULTS

Nine studies (N = 1349) formed the data set. The pooled patient population was 52 ± 2 years of age, 51% male, with low to intermediate pretest probability for ACS. Risk factors included 12% diabetes, 42% hypertension, 35% smokers, 29% had hyperlipidemia, and 7% known CAD. ACS was subsequently diagnosed in 10% of patients. The bivariate summary estimate of sensitivity of CTA for ACS diagnosis was 95% (95% CI 88-100) and specificity was 87% (95% CI 83-92), yielding a negative likelihood ratio of 0.06 (95% CI 0-0.14) and positive likelihood ratio of 7.4 (95% CI 4.8-10). The 30-day event rate included no deaths and no additional MIs.

CONCLUSION

Coronary CTA demonstrates a high sensitivity and a low negative likelihood ratio of 0.06, and is effective in ruling out the presence of ACS in low to intermediate risk patients presenting to the ED with acute chest pain.

Low levels of high-density lipoproteins cholesterol are independently associated with acute coronary heart disease in patients hospitalized for chest pain

INTRODUCTION AND OBJECTIVES

The role of high-density lipoproteins in the context of acute chest pain has not been well characterized. The objective of this study was to determine the relative contribution of lipid profile to the risk of acute coronary syndrome in patients admitted to a cardiology ward for chest pain.

METHODS

We included all consecutive admissions in a single cardiology department over a period of 10 months and 1-year follow-up was performed.

RESULTS

In total, 959 patients were included: 457 (47.7%) were diagnosed with non-ischemic chest pain, 355 (37%) with non-ST-elevation acute coronary syndrome, and 147 (15.3%) with ST-elevation acute coronary syndrome. Prevalence of high-density lipoproteins <40 mg/dL was 54.6%, and was higher in patients with acute coronary syndrome (69.4% vs 30.6%; P<.01). The prevalence of acute coronary syndrome increased with reductions in mean high-density lipoproteins. Age, active smoking, diabetes, fasting glucose >100 mg/dL, and high-density lipoproteins <40 mg/dL were independently associated with acute coronary syndrome, and low high-density lipoproteins was the main associated factor (odds ratio, 4.11; 95% confidence interval, 2.87-5.96). Survival analysis determined that, compared with non-ischemic chest pain, the presence of acute coronary syndrome was associated with significantly greater risk of all-cause and cardiovascular mortality.

CONCLUSIONS

Low levels of high-density lipoproteins cholesterol (≤40 mg/dL) were independently associated with a diagnosis of acute coronary syndrome in patients hospitalized for chest pain, with an inverse relationship between lower levels of high-density lipoproteins and prevalence of acute coronary syndrome.

Contrast stress-echocardiography predicts cardiac events in patients with suspected acute coronary syndrome but nondiagnostic electrocardiogram and normal 12-hour troponin

BACKGROUND

No large study has demonstrated that any stress test can risk-stratify future hard cardiac events (cardiac death or myocardial infarction) in patients with suspected acute coronary syndromes (ACS), nondiagnostic electrocardiographic (ECG) findings, and normal troponin levels. The aim of this study was to test the hypothesis that combined contrast wall motion and myocardial perfusion echocardiographic assessment (cMCE) during stress echocardiography can predict long-term hard cardiac events in patients with suspected ACS, nondiagnostic ECG findings, and normal troponin.

METHODS

A total of 545 patients referred for contrast stress echocardiography from the emergency department for suspected ACS but nondiagnostic ECG findings and normal troponin levels at 12 hours were followed up for cardiac events. Patients underwent dipyridamole-atropine echocardiography with adjunctive myocardial perfusion imaging using a commercially available ultrasound contrast medium (SonoVue).

RESULTS

During a median follow-up period of 12 months, 25 cardiac events (4.6%) occurred (no deaths, 12 nonfatal myocardial infarctions, 13 episodes of unstable angina). Abnormal findings on cMCE were the most significant predictor of both hard cardiac events (hazard ratio, 22.8; 95% confidence interval, 2.9-176.7) and the combined (cardiac death, myocardial infarction, or unstable angina requiring revascularization) end point (hazard ratio, 10.7; 95% confidence interval, 3.7-31.3). The inclusion of the cMCE variable significantly improved multivariate models, determining lower Akaike information criterion values and higher discrimination ability.

CONCLUSIONS

cMCE during contrast stress echocardiography provided independent information for predicting hard and combined cardiac events beyond that predicted by stress wall motion abnormalities in patients with suspected ACS, nondiagnostic ECG findings, and normal troponin levels.

Biochemical markers in acute coronary syndrome

Owing to their higher risk for cardiac death or ischemic complications, patients with acute coronary syndrome (ACS) must be identified from other causes of chest pain. Patients with acute coronary syndrome are divided into categories based on their electrocardiogram; those with new ST-segment elevation and those who present with ST-segment depression. The subgroups of patients with ST-segment elevation are candidates for immediate reperfusion, while fibrinolysis appears harmful for those with non-ST elevation myocardial infarction. There is increasing evidence to encourage appropriate risk stratification before deciding on a management strategy (invasive or conservative) for each patient. The TIMI, GRACE or PURSUIT risk models are recommended as useful for decisions regarding therapeutic options. Cardiac biomarkers are useful additions to these clinical tools to correctly risk stratify ACS patients. Cardiac troponin is the biomarker of choice to detect myocardial necrosis and is central to the universal definition of myocardial infarction. The introduction of troponin assays with a lower limit of detection will allow for earlier diagnosis of patients who present with chest pain. Analytical and clinical validations of these new assays are currently in progress. The question is whether the lower detection limit of the troponin assays will be able to indicate myocardial ischemia in the absence of myocardial necrosis. Previous to the development of ultrasensitive cardiac troponin assays free fatty acids unbound to albumin and ischemia modified albumin were proposed as biochemical markers of ischemia. Advances in our knowledge of the pathogenesis of acute coronary thrombosis have stimulated the development of new biomarkers. Markers of left ventricular performance (N-terminal pro-brain natriuretic peptide) and inflammation (e.g. C-reactive protein) are generally recognized as risk indicators. Studies suggest that using a number of biomarkers clinicians can risk stratify patients over a broad range of short and long term cardiac events. Nevertheless, it is still under debate as to which biomarker combination is best preferred for risk prediction. This review will focus on recent practice guidelines for the management of patients with ACS as well as current advances in cardiac biomarkers, their integration into clinical care and their diagnostic, prognostic and therapeutic utility.

Usefulness of contrast stress-echocardiography or exercise-electrocardiography to predict long-term acute coronary syndromes in patients presenting with chest pain without electrocardiographic abnormalities or 12-hour troponin elevation

The evaluation of patients presenting to the hospital with a recent episode of chest pain suggestive of myocardial ischemia, nondiagnostic electrocardiographic findings, and normal 12-hour cardiac troponin levels remains a challenge for the clinician. We selected 1,081 consecutive patients who presented to the emergency department during 2008 for a chest pain complaint of suspected cardiac origin without significant electrocardiographic abnormalities or troponin elevation. These patients underwent either contrast-enhanced stress-echocardiography with myocardial perfusion imaging or exercise-electrocardiography within 5 days of the index admission. We analyzed their 1-year cardiac outcome (i.e., unstable angina, myocardial infarction, or cardiac death). A post test likelihood of cardiac events was determined on the basis of the results of the provocative testing. Significantly better event-free survival (log-rank p <0.0001) was found for both hard (cardiac death and nonfatal myocardial infarction) and combined (acute coronary syndrome) end points in patients with normal contrast-enhanced stress-echocardiographic findings. However, this was not the case for patients in the exercise-electrocardiographic group, for whom event-free survival was not significantly different among the 3 possible result categories (normal, indeterminate, and abnormal test findings; log-rank p = NS). In conclusion, inducible ischemia detected by contrast-enhanced stress-echocardiography predicted the 1-year incidence of acute coronary syndrome (11.3% for positive vs 0.8% for negative results). However, this was not the case for exercise-electrocardiography, with a 2.7%, 2.3%, and 2.9% 1-year incidence of acute coronary syndromes for positive, negative, and indeterminate results, respectively.

Ruling out coronary artery disease in primary care: development and validation of a simple prediction rule

BACKGROUND

Chest pain can be caused by various conditions, with life-threatening cardiac disease being of greatest concern. Prediction scores to rule out coronary artery disease have been developed for use in emergency settings. We developed and validated a simple prediction rule for use in primary care.

METHODS

We conducted a cross-sectional diagnostic study in 74 primary care practices in Germany. Primary care physicians recruited all consecutive patients who presented with chest pain (n = 1249) and recorded symptoms and findings for each patient (derivation cohort). An independent expert panel reviewed follow-up data obtained at six weeks and six months on symptoms, investigations, hospital admissions and medications to determine the presence or absence of coronary artery disease. Adjusted odds ratios of relevant variables were used to develop a prediction rule. We calculated measures of diagnostic accuracy for different cut-off values for the prediction scores using data derived from another prospective primary care study (validation cohort).

RESULTS

The prediction rule contained five determinants (age/sex, known vascular disease, patient assumes pain is of cardiac origin, pain is worse during exercise, and pain is not reproducible by palpation), with the score ranging from 0 to 5 points. The area under the curve (receiver operating characteristic curve) was 0.87 (95% confidence interval [CI] 0.83-0.91) for the derivation cohort and 0.90 (95% CI 0.87-0.93) for the validation cohort. The best overall discrimination was with a cut-off value of 3 (positive result 3-5 points; negative result <or= 2 points), which had a sensitivity of 87.1% (95% CI 79.9%-94.2%) and a specificity of 80.8% (77.6%-83.9%).

INTERPRETATION

The prediction rule for coronary artery disease in primary care proved to be robust in the validation cohort. It can help to rule out coronary artery disease in patients presenting with chest pain in primary care.

Prognostic differences between routine invasive and conservative strategies for the management of high-risk, non-ST segment acute coronary syndromes: Experience from two consecutive periods in a single center

BACKGROUND

The optimal revascularization strategy for non-ST elevation acute coronary syndromes (NSTE-ACS) remains controversial, especially in a real world context. The objective of this work was to assess differences at 1 year in all-cause mortality and the composite endpoint of mortality or acute myocardial infarction (MI) between two management strategies for NSTE-ACS: a conservative strategy (CS) versus a routine invasive strategy (RIS).

METHODS

Of 799 consecutive patients admitted to our institution, 369 were treated with CS (from January 2001 to October 2002); 430 patients admitted with the same diagnosis were treated with RIS (from November 2002 to November 2004). A propensity score (PS) matched sample was created and included 694 patients (87% of the original population). The event rate was compared between each paired member of the PS-matched sample, one receiving RIS and the other CS, and their differences were tested by Cox proportional analysis.

RESULTS

No significant differences in baseline characteristics were noted between the two management cohorts. By design, the rate of in-hospital catheterization and revascularization procedures increased in RIS compared with CS. The mortality rate was lower, but not significant, in RIS (HR: 0.76, 95% CI=0.51-1.11; p=0.155). For the composite of death or MI, RIS showed a relative risk reduction of 29% (HR: 0.71, 95% CI=0.53-0.94); p=0.018) compared with CS, differences that become non-significant (p=0.680) if we adjust for differences in rate of revascularization procedures and changes in medication prescription.

CONCLUSIONS

RIS was associated with a 1-year lower risk of the combined endpoint of all-cause death and MI in patients with NSTE-ACS, attributable to changes in frequency of revascularization procedures and in medical treatment.

Yield of early rest and stress myocardial perfusion single-photon emission computed tomography and electrocardiographic exercise test in patients with atypical chest pain, nondiagnostic electrocardiogram, and negative biochemical markers in the emergency department

There are no studies in which diagnostic yield of early rest myocardial perfusion gated single-photon emission computed tomography (SPECT), electrocardiographic exercise testing, and stress SPECT were compared in patients with atypical chest pain, nondiagnostic electrocardiograms (ECGs), and negative markers of myocardial damage in the emergency department. A prospective study of 96 patients who presented with atypical chest pain and nondiagnostic ECG, but without elevated markers of necrosis, was performed. All underwent rest gated SPECT using technetium-99m methoxyisobutyl isonitrile within 6 hours after pain subsided followed by an electrocardiographic exercise test to obtain stress-rest SPECT images. After 1 year, there were no deaths and coronary artery disease was confirmed in only 5 patients. Negative predictive values of the 3 techniques were high (99%, 96%, and 100%, respectively), but positive predictive values were low (27%, 22%, and 14%, respectively). Sensitivities of early SPECT (80%) and stress SPECT (100%) were higher than for the electrocardiographic exercise test (40%). In conclusion, in patients with atypical chest pain, nondiagnostic ECG, and negative biochemical markers, negative predictive values of the 3 tests analyzed are very high. The sensitivity of radionuclide tests is higher, but their widespread use does not appear warranted because their positive predictive value and incidence of complications is low.

Clinical risk scoring beyond initial troponin values: results from a large, prospective, unselected acute chest pain population

BACKGROUND

Risk stratifying the diverse group of patients who present to hospital with chest discomfort remains challenging. Current clinical risk models, typically derived from selected populations, are limited by their relative complexity and the absence of a well-defined role of troponin.

OBJECTIVE

To derive a simple clinical risk score from a large, unselected population of patients with chest discomfort and to delineate the prognostic value of an initial troponin measurement.

METHODS

Prospective, consecutive data were collected from patients who presented to a tertiary care hospital. Multivariate analysis was used to identify variables predictive of the primary end point: death, nonfatal myocardial infarction or revascularization at 30 days. Integer values were assigned, generating a risk score to quantify individual patient risk.

RESULTS

Among 1054 patients, predictor variables included ST-segment deviation (strongest predictor -- assigned two points), male sex, prior congestive heart failure, three or more cardiac risk factors and prior acetylsalicylic acid use (one point each). There was a progressive increase in events with increasing total score (P<0.0001), with a 15-fold gradient from scores of 0 to 4 and greater. Although a negative troponin measurement was associated with fewer events for all scores, patients with higher scores remained exposed to substantial risk. A negative initial troponin measurement conferred a negative predictive value of 97.3% (95% CI 93.7% to 99.1%) among patients with a risk score of 0.

CONCLUSION

Significant 30-day events occurred in patients with elevated risk scores, despite negative initial troponin measurements, emphasizing the importance of clinical risk stratification. This simple clinical risk score, in conjunction with a single troponin I measurement, facilitates triage of patients who present to hospital with chest discomfort.

A practical approach with outcome for the prognostic assessment of non-ST-segment elevation chest pain and normal troponin

Patients with non-ST-elevation chest pain constitute a heterogeneous population. Our aim is to compare the outcome of patients with chest pain, non-ST-segment deviation, and normal troponin, categorized using a risk score, with that of patients with ST depression or troponin increase. A total of 1,449 patients with non-ST-elevation chest pain were evaluated. A validated risk score (using pain characteristics and risk factors) was applied to patients without ST depression or troponin increase. Accordingly, 4 risk categories were defined: group 1, no troponin increase, no ST depression, and risk score <3 points (n = 633); group 2, no troponin increase, no ST depression, but risk score > or = 3 points (n = 158); group 3, no troponin increase, ST depression (n = 106); and group 4, troponin increase (n = 552). Median follow-up was 26 months, and the end point was death or myocardial infarction. Group 1 experienced fewer events at 30 days (1.7%, p = 0.0001) and long-term follow-up (9.4%, p = 0.0001) than groups 2 (10.8% and 26%), 3 (6.6% and 30%), and 4 (9.5% and 25%). Kaplan-Meier curves overlapped among groups 2, 3, and 4, whereas group 1 showed a flatter curve (p = 0.0001). Using multivariate analysis, risk group (group 1 vs remaining groups) predicted 30-day (p = 0.0003) and long-term (p = 0.0001) outcome. There were no differences among groups 2, 3, and 4. In conclusion, application of a risk score to patients without troponin increase or ST deviation identified a high-risk group with prognosis similar to that of patients with troponin increase or ST depression and affords a practical classification for the full spectrum of non-ST-elevation chest pain.

Sixty-four–slice computed tomographic coronary angiography: will the “triple rule out” change chest pain evaluation in the ED?

Sixty-four-slice computed tomographic (CT) coronary angiography is a new technique for the noninvasive visualization of the coronary arteries. It enables noninvasive detection of coronary plaque and determination of severity without instrumentation of the heart. Although not yet commonly used in the emergency department setting, it stands poised to dramatically change the way that patients with chest pain are evaluated. In addition to evaluation of the coronary arteries, CT angiography has long been used to evaluate patients for other dangerous causes of chest pain such as aortic dissection and pulmonary embolus. Although these new scanners excel at all of these diagnostic modalities, the true excitement is in the possibility of combining several different protocols into one, allowing for multiple causes of chest pain to be "ruled out" simultaneously. This article describes the current state of the art of cardiac CT, current state of research, and current areas of controversy.

Troponin assays for the diagnosis of myocardial infarction and acute coronary syndrome: where do we stand?

Under normal circumstances, most intracellular troponin is part of the muscle contractile apparatus, and only a small percentage (< 2-8%) is free in the cytoplasm. The presence of a cardiac-specific troponin in the circulation at levels above normal is good evidence of damage to cardiac muscle cells, such as myocardial infarction, myocarditis, trauma, unstable angina, cardiac surgery or other cardiac procedures. Troponins are released as complexes leading to various cut-off values depending on the assay used. This makes them very sensitive and specific indicators of cardiac injury. As with other cardiac markers, observation of a rise and fall in troponin levels in the appropriate time-frame increases the diagnostic specificity for acute myocardial infarction. They start to rise approximately 4-6 h after the onset of acute myocardial infarction and peak at approximately 24 h, as is the case with creatine kinase-MB. They remain elevated for 7-10 days giving a longer diagnostic window than creatine kinase. Although the diagnosis of various types of acute coronary syndrome remains a clinical-based diagnosis, the use of troponin levels contributes to their classification. This Editorial elaborates on the nature of troponin, its classification, clinical use and importance, as well as comparing it with other currently available cardiac markers.

Prognostic usefulness of white blood cell count on admission and one-year outcome in patients with non-ST-segment elevation acute chest pain

Little is known about the prognostic value of leukocyte count on admission for patients with chest pain. In total, 1,461 patients who presented to the emergency department with non-ST-segment elevation chest pain were studied by clinical history, electrocardiography, serial troponin I determination, and leukocyte count on admission. End points were 1-year mortality and major events (mortality or infarction). Overall patient distribution by quartiles of leukocyte count showed increased mortality (6%, 7%, 6%, and 17%, p = 0.0001) and major events (13%, 13%, 15%, and 24%, p = 0.0001) in the fourth quartile. After adjustment for other risk factors, the fourth quartile cut-off value (>10,000 cells/ml) predicted mortality (hazard ratio 2.0, 95% confidence interval 1.4 to 2.8, p = 0.0001) but not major events (p = 0.07). When analysis was performed to assess troponin status, in the subgroup with increased troponin (n = 634, 16% mortality), a leukocyte count >10,000 cells/ml was related to mortality (hazard ratio 2.2, 95% confidence interval 1.5 to 3.4, p = 0.0001). However, in the subgroup with normal troponin levels (n = 827, 4.2% mortality), there were no differences in mortality between patients with or without a leukocyte count >10,000 cells/ml (4.4% vs 4.2%, p = 0.8), with survival curves showing a tight overlap (p = 0.9). Further, in the subgroup with normal troponin levels, leukocyte count was not significantly different between patients with or without ST depression (7,969 +/- 2,171 vs 8,108 +/- 2,356 cells/ml, p = 0.6) and was not associated with mortality in patients with ST depression (p = 0.7). In conclusion, leukocyte count on admission is predictive of mortality in patients with chest pain and non-ST-segment elevation myocardial infarction. However, in the absence of myocardial necrosis, leukocyte count lacks prognostic value.

[Predictive value of chest pain score for the diagnosis of acute coronary syndromes]

BACKGROUND AND OBJECTIVE

We analyzed the diagnostic utility of a chest pain score in patients evaluated for chest pain of possible coronary origin.

PATIENTS AND METHOD

We studied 1,068 consecutive patients coming to the emergency room with acute chest pain of possible coronary origin without ST-segment elevation, using a chest pain unit protocol. Chest pain was quantified by validated score (0-20 points). The diagnostic value of the chest pain score was analyzed for the diagnosis of acute myocardial infarction (AMI), unstable angina (UA) and acute coronary syndrome (ACS; AMI or UA).

RESULTS

The diagnosis of ACS was established in 651 patients (61%), AMI in 439 (41%) and UA in 212 (20%). In the multivariate analysis a chest pain score > or = 10 was an independent predictor of ACS (odds ratio [OR] = 2.9; 95% confidence interval [CI] 2.1-4; p = 0.0001), along with an age older than 70 years (OR = 2.6; 95% CI,1.8-3.7; p = 0.0001), male gender (OR = 2; 95% CI, 1.4-2.8; p = 0.0001); insulin-dependent diabetes (OR = 2.3; 95% CI, 1.2-4.6; p = 0.016); previous myocardial infarction (OR = 1.6; 95% CI, 1.1-2.4; p = 0.022), ST depression (OR = 9.3; 95% CI, 5.2-16.7; p = 0.0001) and T wave inversion (OR = 2.5; 95% CI, 1.4-4.3; p = 0.0001). The chest pain score was associated with the diagnosis of both AMI (OR = 1.4; 95% CI, 1.1-1.9; p < 0.02) and UA (OR = 2.8; 95% CI, 1.8-4.2; p < 0.0001).

CONCLUSIONS

The chest pain score allows independent information for the early diagnosis of patients coming to the emergency department with acute chest pain of possible coronary origin.

Usefulness of early exercise testing and clinical risk score for prognostic evaluation in chest pain units without preexisting evidence of myocardial ischemia

We investigated whether the result of early exercise testing yields prognostic information in addition to that afforded by a clinical risk score in patients who present with chest pain in the emergency department. The study group consisted of 340 patients without preexisting evidence of myocardial ischemia. A clinical risk score was calculated. Primary (mortality or myocardial infarction) and secondary (mortality, myocardial infarction, or rehospitalization due to unstable angina) end points at 1 year were defined. Patients with a positive exercise test result underwent invasive management. Frequencies of primary (7.4% vs 2.1%, p = 0.06) and secondary (9.3% vs 2.8%, p = 0.04) end points and risk score (1.6 +/- 1.0 vs 1.0 +/- 0.9 points, p = 0.0001) were higher in patients with a positive exercise test result. However, in multivariate analysis, clinical risk score was the only independent predictor for the primary (hazard ratio 2.0, 95% confidence interval 1.2 to 3.2, p = 0.004) and secondary (hazard ratio 1.9, 95% confidence interval 1.2 to 2.9, p = 0.003) end points. In conclusion, if a policy of invasive management is implemented for patients with positive exercise test results, the clinical risk score constitutes the main prognostic predictor of 1-year outcome.

New Risk Score for Patients With Acute Chest Pain, Non-ST-Segment Deviation, and Normal Troponin Concentrations

OBJECTIVES

The purpose of this research was to develop a risk score for patients with chest pain, non-ST-segment deviation electrocardiogram (ECG), and normal troponin levels.

BACKGROUND

Prognosis assessment in this population remains a challenge.

METHODS

A total of 646 consecutive patients were evaluated by clinical history (risk factors and chest pain score according to pain characteristics), ECG, and early exercise testing. ST-segment deviation and troponin elevation were exclusion criteria. The primary end point was mortality or myocardial infarction at one year. The secondary end point was mortality, myocardial infarction, or urgent revascularization at 14 days (similar to the Thrombolysis In Myocardial Infarction [TIMI] risk score).

RESULTS

Primary and secondary end point rates were 6.7% and 5.4%. A risk score was constructed using the variables related to the primary end point: chest pain score > or =10 points (hazard ratio [HR] = 2.5; 1 point), > or =2 pain episodes in last 24 h (HR = 2.2; 1 point), age > or =67 years (HR = 2.3; 1 point), insulin-dependent diabetes mellitus (HR = 4.2; 2 points), and prior percutaneous transluminal coronary angioplasty (HR = 2.2; 1 point). Patients were classified into five categories of risk (p = 0.0001): 0 points, 0% event rate; 1 point, 3.1%; 2 points, 5.4%; 3 points, 17.6%; > or =4 points, 29.6%. The accuracy of the score was greater than that of the TIMI risk score for the primary (C index of 0.78 vs. 0.66, p = 0.0002) and secondary (C index of 0.70 vs. 0.66, p = 0.1) end points.

CONCLUSIONS

Patients presenting with chest pain despite no ST-segment deviation or troponin elevation show a non-negligible rate of events at one year. A risk score derived from this specific population allows more accurate stratification than when using the TIMI risk score.