The health care burden of acute chest pain

Use of Observed Within-Person Variation of Cardiac Troponin in Emergency Department Patients for Determination of Biological Variation and Percentage and Absolute Reference Change Values

BACKGROUND

Many patients presenting to the emergency department (ED) for assessment of possible acute coronary syndrome (ACS) have low cardiac troponin concentrations that change very little on repeat blood draw. It is unclear if a lack of change in cardiac troponin concentration can be used to identify acutely presenting patients at low risk of ACS.

METHODS

We used the hs-cTnI assay from Abbott Diagnostics, which can detect cTnI in the blood of nearly all people. We identified a population of ED patients being assessed for ACS with repeat cTnI measurement who ultimately were proven to have no acute cardiac disease at the time of presentation. We used data from the repeat sampling to calculate total within-person CV (CVT) and, knowing the assay analytical CV (CVA), we could calculate within-person biological variation (CVi), reference change values (RCVs), and absolute RCV delta cTnI concentrations.

RESULTS

We had data sets on 283 patients. Men and women had similar CVi values of approximately 14%, which was similar at all concentrations <40 ng/L. The biological variation was not dependent on the time interval between sample collections (t = 1.5–17 h). The absolute delta critical reference change value was similar no matter what the initial cTnI concentration was. More than 90% of subjects had a critical reference change value <5 ng/L, and 97% had values of <10 ng/L.

CONCLUSIONS

With this hs-cTnI assay, delta cTnI seems to be a useful tool for rapidly identifying ED patients at low risk for possible ACS.

Effectiveness of the Chest Pain Choice decision aid in emergency department patients with low-risk chest pain: study protocol for a multicenter randomized trial

Background

Chest pain is the second most common reason patients visit emergency departments (EDs) and often results in very low-risk patients being admitted for prolonged observation and advanced cardiac testing. Shared decision-making, including educating patients regarding their 45-day risk for acute coronary syndrome (ACS) and management options, might safely decrease healthcare utilization.

Methods/Design

This is a protocol for a multicenter practical patient-level randomized trial to compare an intervention group receiving a decision aid, Chest Pain Choice (CPC), to a control group receiving usual care. Adults presenting to five geographically and ethnically diverse EDs who are being considered for admission for observation and advanced cardiac testing will be eligible for enrollment. We will measure the effect of CPC on (1) patient knowledge regarding their 45-day risk for ACS and the available management options (primary outcome); (2) patient engagement in the decision-making process; (3) the degree of conflict patients experience related to feeling uninformed (decisional conflict); (4) patient and clinician satisfaction with the decision made; (5) the rate of major adverse cardiac events at 30 days; (6) the proportion of patients admitted for advanced cardiac testing; and (7) healthcare utilization. To assess these outcomes, we will administer patient and clinician surveys immediately after each clinical encounter, obtain video recordings of the patient-clinician discussion, administer a patient healthcare utilization diary, analyze hospital billing records, review the electronic medical record, and conduct telephone follow-up.

Discussion

This multicenter trial will robustly assess the effectiveness of a decision aid on patient-centered outcomes, safety, and healthcare utilization in low-risk chest pain patients from a variety of geographically and ethnically diverse EDs.

Trial registration

NCT01969240.

The Manchester Acute Coronary Syndromes (MACS) decision rule for suspected cardiac chest pain: derivation and external validation

Objective

We aimed to derive and validate a clinical decision rule (CDR) for suspected cardiac chest pain in the emergency department (ED). Incorporating information available at the time of first presentation, this CDR would effectively risk-stratify patients and immediately identify: (A) patients for whom hospitalisation may be safely avoided; and (B) high-risk patients, facilitating judicious use of resources.

Methods

In two sequential prospective observational cohort studies at heterogeneous centres, we included ED patients with suspected cardiac chest pain. We recorded clinical features and drew blood on arrival. The primary outcome was major adverse cardiac events (MACE) (death, prevalent or incident acute myocardial infarction, coronary revascularisation or new coronary stenosis >50%) within 30 days. The CDR was derived by logistic regression, considering reliable (κ>0.6) univariate predictors (p<0.05) for inclusion.

Results

In the derivation study (n=698) we derived a CDR including eight variables (high sensitivity troponin T; heart-type fatty acid binding protein; ECG ischaemia; diaphoresis observed; vomiting; pain radiation to right arm/shoulder; worsening angina; hypotension), which had a C-statistic of 0.95 (95% CI 0.93 to 0.97) implying near perfect diagnostic performance. On external validation (n=463) the CDR identified 27.0% of patients as ‘very low risk’ and potentially suitable for discharge from the ED. 0.0% of these patients had prevalent acute myocardial infarction and 1.6% developed MACE (n=2; both coronary stenoses without revascularisation). 9.9% of patients were classified as ‘high-risk’, 95.7% of whom developed MACE.

Conclusions

The Manchester Acute Coronary Syndromes (MACS) rule has the potential to safely reduce unnecessary hospital admissions and facilitate judicious use of high dependency resources.

Undetectable high-sensitivity cardiac troponin T level in the emergency department and risk of myocardial infarction

OBJECTIVES

This study sought to evaluate if an undetectable (<5 ng/l) high-sensitivity cardiac troponin T (hs-cTnT) level and an electrocardiogram (ECG) without signs of ischemia can rule out myocardial infarction (MI) in the emergency department (ED).

BACKGROUND

Chest pain is a common symptom often associated with benign conditions, but may be a sign of MI. Because there is no rapid way to rule out MI, many patients are admitted to the hospital.

METHODS

All patients who sought medical attention for chest pain and had at least 1 hs-cTnT analyzed during 2 years at the Karolinska University Hospital, Stockholm, Sweden, were included. We calculated the negative predictive values of an undetectable hs-cTnT and ECG without ischemia for MI and death within 30 days.

RESULTS

We included 14,636 patients, of whom 8,907 (61%) had an initial hs-cTnT of <5 ng/l; 21% had 5 to 14 ng/l, and 18% had >14 ng/l. During 30-day follow-up, 39 (0.44%) patients with undetectable hs-cTnT had a MI, of whom 15 (0.17%) had no ischemic ECG changes. The negative predictive value for MI within 30 days in patients with undetectable hs-cTnT and no ischemic ECG changes was 99.8% (95% confidence interval [CI]: 99.7 to 99.9). The negative predictive value for death was 100% (95% CI: 99.9 to 100).

CONCLUSIONS

All patients with chest pain who have an initial hs-cTnT level of <5 ng/l and no signs of ischemia on an ECG have a minimal risk of MI or death within 30 days, and can be safely discharged directly from the ED.

Diagnostic role of coronary calcium scoring in the rapid access chest pain clinic: prospective evaluation of NICE guidance

BACKGROUND

Coronary artery calcium (CAC) imaging by unenhanced computed X-ray tomography (CT) is recommended as an initial diagnostic test for patients with stable chest pain symptoms but a low likelihood (10-29%) of underlying obstructive coronary artery disease (CAD) after clinical assessment. The recommendation has not previously been tested prospectively in a rapid access chest pain clinic (RACPC).

METHODS

We recruited 300 consecutive patients presenting with stable chest pain to the RACPC of three hospitals. All patients underwent CAC imaging, followed by invasive coronary angiography (ICA) in patients with CAC ≥ 1000 Agatston units (Au) and CT coronary angiography (CTCA) in those with CAC <1000. Patients with 50-70% stenosis on CTCA underwent myocardial perfusion scintigraphy (MPS) while those with ≥ 70% stenosis underwent ICA. Obstructive CAD was defined as ≥ 70% stenosis on ICA or the presence of inducible ischaemia on MPS. Patients were followed up clinically for a mean of 17 (SD 6) months.

RESULTS

The mean patient age was 60.6 (SD 9.6) years and 48% were males. Obstructive CAD was found in 56 (19%) patients, of whom 42 (14%) underwent revascularization. CAC was zero in 131 (44%) patients, of whom two (1.5%) had obstructive CAD and one (0.8%) underwent revascularization. The sensitivity, specificity, negative predictive value, and positive predictive value of CAC ≥ 1 for detection of obstructive CAD were 96, 53, 32, and 98%, respectively. None of the 57 patients with low pre-test probability of CAD and zero CAC had obstructive CAD or suffered a cardiovascular event during the follow-up.

CONCLUSION

Patients with stable chest pain symptoms but a low likelihood of CAD can safely be diagnosed as not having obstructive CAD in the absence of detectable coronary calcification by unenhanced CT. Patients with CAC >400 Au have a high prevalence of obstructive CAD and further investigation with ICA or functional imaging may be warranted rather than CTCA. These findings support NICE guidance for the investigation of stable chest pain. ClinicalTrials gov identifier: NCT01464203.

Short-Term Outcome of Discharged Low-Risk Chest Pain without Provoke Ischemia Study

INTRODUCTION

Chest pain is a common problem in patients referring to emergency units. The present study was undertaken to evaluate the short-term outcome of patients presenting with a low risk chest pain and discharging without provoke ischemia study during emergency department admission.

METHODS

In the present prospective cohort study, patients with low-risk chest pain, referring to the emergency department of Imam Hossein Hospital, Tehran, during the first half of 2012, were evaluated. All the patients underwent electrocardiogram (ECG) and cardiac enzyme tests, including cardiac isoenzymes creatine kinase MB and troponin I. One week after referring to the emergency department, the patients underwent an exercise test and were followed for a month. Data were analyzed with chi-squared test at a significant level of P<0.05.

RESULTS

A total of 252 patients were included. The mean and standard deviation of patient ages was 56±7.7 years (47.5% male). The results of exercise tests for 47 (26.3%) subjects were positive [32 (28.8%) patients in the 41-60 year age group and 15 (22.7%) over 60 years of age].The angiography examination results of 5 patients (2.8%) were abnormal. There were no significant relationships between the age and gender and the results of exercise test and angiography (P>0.05). During the one-month follow-up no cases of mortality, cardiac problems, or referring again to the hospital were recorded.

CONCLUSION

Based on the results of the present study, prevalence of cardiac etiology in patients with low risk chest pain was 2.8% and one-month follow-up did not reveal any complications or serious problems in such cases.

Evaluation and outcomes of patients admitted to a tertiary medical assessment unit with acute chest pain of possible coronary origin

OBJECTIVES

The study aims to (i) profile clinical characteristics, risk estimates of acute coronary syndrome (ACS), use and yield of non-invasive cardiac testing, discharge diagnosis and 30-day outcomes among patients admitted with acute chest pain of possible coronary origin; and (ii) construct a risk stratification algorithm that informs management decisions.

METHODS

This is a retrospective cohort study of 130 consecutive patients admitted to a tertiary hospital medical assessment unit between 24 January and 22 March 2012. Estimates of ACS risk were based on Australian guidelines and Thrombolysis in Myocardial Infarction (TIMI) scores.

RESULTS

Patients were of mean age 61 years, 45% had known coronary artery disease (CAD), 58% presented with typical ischaemic pain, 82% had intermediate to high ACS risk and 61% underwent testing. Myocardial ischaemia was cardiologist-confirmed discharge diagnosis in 29% of patients, and was associated with known CAD, typical pain, multiple risk factors and high TIMI risk scores (P < 0.001 for all associations). Of 98 non-invasive investigations, 9% (95% CI, 5-17%) were positive for myocardial ischaemia. Major adverse event rate at 30 days was 0.8% (95% CI, <0.1-6%). An algorithm was constructed that integrates known CAD, ACS risk and TIMI scores in identifying low-risk patients capable of rapid discharge from EDs without further investigation, and classifying the remainder into risk groups that informs choice of investigations and need for telemetry.

CONCLUSIONS

In patients with indeterminate chest pain, clinical features and risk scores identify most with myocardial ischaemia. An algorithm is presented that might inform triaging, early discharge, choice of testing and need for telemetry.

A clinical scoring system in undifferentiated chest pain predicting undetectable troponin concentration

BACKGROUND

Chest pain is the most common reason for emergency admission to hospital, but the majority of these are due to non-cardiac pain. We sought to determine which combination of clinical features is more likely to predict an undetectable troponin level in patients presenting with chest pain.

METHODS

We collected data over a two-month period on consecutive patients presenting acutely to hospital with chest pain and who had a troponin I measured. We recorded basic demographics, risk factors, pain distribution, associated symptoms, physical findings and ECG changes. The parameters significantly associated with troponin positivity were entered into a stepwise logistic regression analysis and the resulting model's coefficients were used to construct a simple clinical score to categorise patients into low, medium or high probability of having a positive troponin.

RESULTS

26 of 157 (16.6%) patients had a positive troponin. The variables retained in the regression model were: age >65, heart rate >80, previous myocardial infarction, diabetes and pain radiating to either arm. The model showed good discrimination (area under ROC curve 0.869, 95% CI 0.806 - 0.917). Using the regression model's coefficients, patients were grouped into low, intermediate or high probability groups. Being in the low probability group had a negative predictive value of 97.8% and being in the high probability group had a positive predictive value of 65.2%. The majority (73.9%) of patients could be categorised as either low or high probability.

DISCUSSION

This simple scoring system, if prospectively validated, may be useful in identifying low risk patients with chest pain who are unlikely to have elevation of serum troponin concentration.

Increased urinary IgM excretion in patients with chest pain due to coronary artery disease

BACKGROUND

Micro-albuminuria is a recognized predictor of cardiovascular morbidity and mortality in patients with coronary artery disease. We have previously reported, in diabetic and non-diabetic patients, that an increased urinary excretion of IgM is associated with higher cardiovascular mortality. The purpose of this study was to investigate the pattern of urinary IgM excretion in patients with acute coronary syndrome (ACS) and its correlation to cardiovascular outcome.

METHODS

Urine albumin, and IgM to creatinine concentration ratios were determined in 178 consecutive patients presenting with chest pain to the Department of Emergency Medicine (ED) at the University Hospital of Lund. Fifty eight (23 female) patients had ACS, 55 (19 female) patients had stable angina (SA), and 65 (35 female) patients were diagnosed as non-specific chest pain (NS).

RESULTS

Urine albumin and IgM excretions were significantly higher in patients with ACS (p = 0.001, and p = 0.029, respectively) compared to patients with NS-chest pain. During the 2 years follow-up time, 40 (19 female) patients suffered a new major cardiovascular event (ACS, acute heart failure, stroke) and 5 (4 male/1 female) patients died of cardiovascular cause. A high degree of albuminuria and IgM-uria significantly predicted cardiovascular mortality and morbidity (HR = 2.89, 95% CI: 1.48 - 5.66, p = 0.002). Microalbuminuric patients (≥3 mg/mmol) with high IgM-uria (≥0.005 mg/mmol) had a 3-fold higher risk for cardiovascular new events compared to patients with low IgM-uria (RR = 3.3, 95% CI: 1.1 - 9.9, p = 0.001).

CONCLUSION

In patients with chest pain, an increased urine IgM excretion, is associated with coronary artery disease and long-term cardiovascular complications. Measuring urine IgM concentration could have a clinical value in risk stratification of patients with ACS.

HEART score: a simple and useful tool that may lower the proportion of chest pain patients who are admitted

OBJECTIVES

Evaluation of patients with chest pain in the emergency department is challenging. HEART score can be easily used and includes history, electrocardiogram (ECG), age, risk factors, and troponin. The aims were to validate this score and estimate to what extent it can reduce the admission rate.

METHODS

A total of 410 consecutive patients with chest pain, who presented to the emergency department with no ST-segment elevations, were included and followed for 3 months regarding the combined endpoint of cardiovascular death, myocardial infarction, or unplanned revascularization.

RESULTS

Thirty (7.3%) patients attained one or more combined endpoint. Of 247 (60.2%) patients with HEART score 0-3, 1 patient (0.4%) had a combined endpoint (unplanned revascularization). Of 144 (35.1%) patients with HEART score 4-6, 19 (13.2%) patients had a combined endpoint. Of 19 (4.6%) patients with HEART score 7-10, 10 (52.6%) patients had a combined endpoint. A total of 181 (44.1%) patients were admitted to the hospital for further evaluation. Of these patients, 62 (34.3%) had a HEART score of 0-3 and of whom 45 (72.5%) had a final diagnosis indicating that hospital admission may have been avoided. Among the 5 HEART score parameters, patient history, ECG abnormalities, and elevated troponin values were independent predictors of the combined endpoint.

CONCLUSIONS

In conclusion, HEART score may be a useful tool for evaluation of patients with chest pain and identify a low-risk group in which admission and further investigations may not be necessary. However, an even simpler score, including only history, troponin level, and ECG findings, may be sufficient.

High-sensitivity cardiac troponins: no more 'negatives'

According to recently published expert guidelines, cardiac troponins are the only accepted biomarkers to define acute myocardial infarction. New high sensitivity cardiac troponin assays provide exciting opportunities for early rule-out and rule-in strategies and for identifying high-risk patients early in their presentation to guide early treatment and intervention. This review briefly discusses the history of troponin testing, before going on to cover clinical uses of the new highly sensitive assays in the early assessment of acute myocardial infection. Common clinical pitfalls with the use of these assays are discussed, as is the use of highly sensitive troponins more widely as prognostic markers. Likely future developments in this area are discussed.

High-sensitive cardiac troponin T

Cardiac troponin is the preferred biomarker for the diagnosis of acute myocardial infarction (AMI). The recent development of a high-sensitive cardiac troponin T (hs-cTnT) assay permits detection of very low levels of cTnT. Using the hs-cTnT assay improves the overall diagnostic accuracy in patients with suspected AMI, while a negative result also has a high negative predictive value. The gain in sensitivity may be particularly important in patients with a short duration from symptom onset to admission. Measurement of cardiac troponin T with the hs-cTnT assay may provide strong prognostic information in patients with acute coronary syndromes, stable coronary artery disease, heart failure and even in the general population; however, increased sensitivity comes at a cost of decreased specificity. Serial testing, as well as clinical context and co-existing diseases, are likely to become increasingly important for the interpretation of hs-cTnT assay results.

Non-invasive imaging in coronary artery disease including anatomical and functional evaluation of ischaemia and viability assessment

Coronary artery disease has an important impact on the morbidity and mortality statistics and health economics worldwide. Diagnosis of coronary artery disease is important in risk stratification and guides further management. Invasive coronary angiography is the traditional method of imaging the coronary arteries and remains the gold standard. It detects luminal stenosis but provides little information about the vessel wall or plaques. Besides, not all anatomical lesions are functionally significant. This has lent itself to a wide variety of imaging techniques to identify and assess a flow-limiting stenosis. The approach to diagnosis of coronary artery disease is broadly based on anatomical and functional imaging. Coronary CT and MRI of coronary arteries provide an anatomical assessment of coronary stenosis. Coronary calcium score and coronary CT assess subclinical atherosclerosis by assessing the atherosclerotic plaque burden. The haemodynamic significance of a coronary artery stenosis can be assessed by stress radioisotope studies, stress echocardiography and stress MRI. The more recent literature also focuses on plaque assessment and identification of plaques that are likely to give rise to an acute coronary syndrome. There is an explosion of literature on the merits and limitations of the different imaging modalities. This review article will provide an overview of all the imaging modalities in the diagnosis of coronary artery disease.

Cardiac troponin: a critical review of the case for point-of-care testing in the ED

The measurement of cardiac troponin concentrations in the blood is a key element in the evaluation of patients with suspected acute coronary syndromes, according to current guidelines, and contributes importantly to the ruling in or ruling out of acute myocardial infarction. The introduction of point-of-care testing for cardiac troponin has the potential to reduce turnaround time for assay results, compared with central laboratory testing, optimizing resource use. Although, in general, many point-of-care cardiac troponin tests are less sensitive than cardiac troponin tests developed for central laboratory-automated analyzers, point-of-care systems have been used successfully within accelerated protocols for the reliable ruling out of acute coronary syndromes, without increasing subsequent readmission rates for this condition. The impact of shortened assay turnaround times with point-of-care technology on length of stay in the emergency department has been limited to date, with most randomized evaluations of this technology having demonstrated little or no reduction in this outcome parameter. Accordingly, the point-of-care approach has not been shown to be cost-effective relative to central laboratory testing. Modeling studies suggest, however, that reengineering overall procedures within the emergency department setting, to take full advantage of reduced therapeutic turnaround time, has the potential to improve the flow of patients through the emergency department, to shorten discharge times, and to reduce cost. To properly evaluate the potential contribution of point-of-care technology in the emergency department, including its cost-effectiveness, future evaluations of point-of-care platforms will need to be embedded completely within a local decision-making structure designed for its use.

Cost burden of non-specific chest pain admissions

BACKGROUND

Non-cardiac aetiologies are common among patients presenting with chest pain.

AIM

To determine the cost of non-specific chest pain admissions to a tertiary referral, teaching hospital.

METHODS

Thrombolysis in myocardial infarction risk (TIMI) risk score, lengths of stay (LOS), investigations and diagnoses were recorded for patients admitted with chest pain. Non-specific chest pain was defined as chest pain where cardiac, pulmonary and gastroesophageal aetiologies were excluded. Costs of admissions were calculated.

RESULTS

Of 80 patients, 34 (4%) and 22 (28%) were diagnosed with non-specific chest pain and acute coronary syndrome, respectively. Non-specific chest pain admissions had a mean age of 54 (11; 35-74) years, LOS of 3.8 (2.6; 1-11) days and TIMI risk score of 1.4 (1.5; 0-5). Acute coronary syndrome admissions had a mean age of 67 (14; 43-94) years, LOS of 7.7 (4.3; 2-16) days and TIMI risk score of 3.1 (1.2; 0-5). The mean cost per non-specific chest pain admission was €3,729 (2,378; 1,034-10,468), or 48% of the mean cost per acute coronary syndrome admission of €7,667 (4,279; 1,963-16,071). Bed day costs account for >90% of overall costs. Only 7% of patients were weekend discharges. The mean interval to exercise stress test was 2.7(1.5; 1-7) days.

CONCLUSIONS

The mean costs of admission and LOS for patients with non-specific chest pain are significant. Extrapolating findings, annual national cost is estimated at approximately €71 million for this cohort, with 73,000 bed days consumed nationally. Delays from admission to tests and low percentage of weekend discharges prolong LOS.

Effect on emergency department efficiency of an accelerated diagnostic pathway for the evaluation of chest pain

OBJECTIVE

To compare ED efficiency measures between a trial period using an accelerated diagnostic pathway (ADP) for chest pain evaluation, and a control period using a traditional diagnostic pathway (TDP).

METHODS

The TDP used cardiac Troponin I assays at arrival and 6 h. The ADP used point-of-care multimarker (myoglobin, creatine kinase-MB fraction and cardiac Troponin I) assays at arrival and 2 h. Outcomes for consecutive eligible patients included ED length of stay (LOS), discharges and admissions within 4 and 8 h, ED occupancy and cardiac cubicle throughput.

RESULTS

There were 413 and 258 eligible patients during the 81 day TDP and 66 day ADP periods. The ED LOS for chest pain patients was reduced in the ADP period for both discharged patients (median 297 [interquartile range {IQR} 230-437]vs 545 [IQR 457-677] min, P < 0.0001) and admitted patients (median 609.5 [IQR 464-857]vs 733.5 [IQR 532-1070] min, P= 0.007). For the whole ED, the percentage of patients discharged or admitted within 4 or 8 h and ED occupancy were similar between periods. Cardiac cubicle throughput increased during the ADP period (217 [95% confidence interval 209.6-224.4]vs 188 [95% confidence interval 174.5-201.8] patients per week, P= 0.005).

CONCLUSIONS

The ADP utilizing point-of-care multimarkers led to significantly shorter ED LOS for both discharged and admitted chest pain patients. This was associated with increased cardiac cubicle throughput, but improvements in other whole ED performance indicators were not demonstrated.

Chiropractic treatment vs self-management in patients with acute chest pain: a randomized controlled trial of patients without acute coronary syndrome

OBJECTIVE

The musculoskeletal system is a common but often overlooked cause of chest pain. The purpose of the present study is to evaluate the relative effectiveness of 2 treatment approaches for acute musculoskeletal chest pain: (1) chiropractic treatment that included spinal manipulation and (2) self-management as an example of minimal intervention.

METHODS

In a nonblinded, randomized, controlled trial set at an emergency cardiology department and 4 outpatient chiropractic clinics, 115 consecutive patients with acute chest pain and no clear medical diagnosis at initial presentation were included. After a baseline evaluation, patients with musculoskeletal chest pain were randomized to 4 weeks of chiropractic treatment or self-management, with posttreatment questionnaire follow-up 4 and 12 weeks later. Primary outcome measures were numeric change in pain intensity (11-point box numerical rating scale) and self-perceived change in pain (7-point ordinal scale).

RESULTS

Both groups experienced decreases in pain, self-perceived positive changes, and increases in Medical Outcomes Study Short Form 36-Item Health Survey scores. Observed between-group significant differences were in favor of chiropractic treatment at 4 weeks regarding the primary outcome of self-perceived change in chest pain and at 12 weeks with respect to the primary outcome of numeric change in pain intensity.

CONCLUSIONS

To the best of our knowledge, this is the first randomized trial assessing chiropractic treatment vs minimal intervention in patients without acute coronary syndrome but with musculoskeletal chest pain. Results suggest that chiropractic treatment might be useful; but further research in relation to patient selection, standardization of interventions, and identification of potentially active ingredients is needed.

The role of non-invasive imaging in patients with suspected acute coronary syndrome

This article gives an overview of the role of imaging in the diagnosis and management of acute coronary syndrome.

Coronary computed tomography angiography for the evaluation of patients with acute chest pain

Acute chest pain is a common presenting complaint of patients attending emergency room departments. Despite this, it can often be challenging to completely exclude a diagnosis of acute coronary syndrome following an initial standard clinical and biochemical evaluation. As a result of this, patients are often admitted to hospital until the treating clinician is satisfied that this diagnosis can be excluded. This process imparts a significant health economic burden by not only increasing hospital bed occupancy rates but also by the unnecessary layering of diagnostic investigations. With the rapid advances in coronary computed tomography angiography (CTA), there has been considerable interest in whether coronary CTA may be a viable alternative to this current standard care. We review the current literature and supporting evidence for utilising coronary CTA in the evaluation of patients presenting with acute chest pain in terms of its diagnostic accuracy, safety, cost-effectiveness and prognostic implications.

Rapid exclusion of acute myocardial infarction in patients with undetectable troponin using a high-sensitivity assay

OBJECTIVES

This paper sought to evaluate whether high sensitivity troponin (hs-cTnT) can immediately exclude acute myocardial infarction (AMI) at a novel 'rule out' cut-off.

BACKGROUND

Subgroup analysis of recent evidence suggests that undetectable hs-cTnT may exclude AMI at presentation.

METHODS

In a cohort study, we prospectively enrolled patients with chest pain, evaluating them with standard troponin T and testing for hs-cTnT (Roche Diagnostics, Basel, Switzerland) at presentation. The primary outcome was a diagnosis of AMI. We also followed up patients for adverse events within 6 months. After subsequent clinical implementation of hs-cTnT, we again evaluated whether initially undetectable hs-cTnT ruled out a subsequent rise.

RESULTS

Of 703 patients in the cohort study, 130 (18.5%) had AMI, none of whom initially had undetectable hs-cTnT (sensitivity: 100.0%, 95% confidence interval [CI]: 95.1% to 100.0%, negative predictive value: 100.0%, 95% CI: 98.1% to 100.0%). This strategy would rule out AMI in 27.7% of patients, 2 (1.0%) of whom died or had AMI within 6 months (1 periprocedural AMI, 1 noncardiac death). We evaluated this approach in an additional 915 patients in clinical practice. Only 1 patient (0.6%) with initially undetectable hs-cTnT had subsequent elevation (to 17 ng/l), giving a sensitivity of 99.8% (95% CI: 99.1% to 100.0%) and a negative predictive value of 99.4% (95% CI: 96.6% to 100.0%).

CONCLUSIONS

Undetectable hs-cTnT at presentation has very high negative predictive value, which may be considered to rule out AMI, identifying patients at low risk of adverse events. Pending further validation, this strategy may reduce the need for serial testing and empirical treatment, enabling earlier reassurance for patients and fewer unnecessary evaluations and hospital admissions.

The challenge of triaging chest pain patients: the bernese university hospital experience

Accurate diagnosis of the causes of chest pain and dyspnea remain challenging. In this preliminary observational study with a 5-year follow-up, we attempted to find a simplified approach to selecting patients with chest pain needing immediate care based on the initial evaluation in ED. During a 24-month period were randomly selected 301 patients and a conditional inference tree (CIT) was used as the basis of the prognostic rule. Common diagnoses were musculoskeletal chest pain (27%), ACS (19%) and panic attack (12%). Using variables of ACS symptoms we estimated the likelihood of ACS based on a CIT to be high at 91% (32), low at 4% (198) and intermediate at 20.5–40% in (71) patients. Coronary catheterization was performed within 24 hours in 91% of the patients with ACS. A culprit lesion was found in 79%. Follow-up (median 4.2 years) information was available for 70% of the patients. Of the 164 patients without ACS who were followed up, 5 were treated with revascularization for stable angina pectoris, 2 were treated with revascularization for myocardial infarction, and 25 died. Although a simple triage decision tree could theoretically help to efficient select patients needing immediate care we need also to be vigilant for those presenting with atypical symptoms.

The feasibility of nurse-led assessment in acute chest pain admissions by means of coronary computed tomography

BACKGROUND

Cardiac computed tomography (CCT) is a non-invasive imaging technique for the diagnosis of coronary artery disease (CAD). The National Institute for Health and Clinical Excellence (NICE) recommend CCT for selected patients in the assessment of chest pain of recent onset.

AIMS

To assess the feasibility and utility of CCT in a nurse-led, protocol-based assessment of chest pain.

METHODS

Patients admitted over 4 months with suspected angina were assessed for eligibility for CCT by a specialist nurse. Eligibility was defined by: a likelihood of CAD < 90%, no features of acute coronary syndrome, no contra-indications to the scanning process, and the ability to give written consent. An age and sex-matched historical cohort (for whom CCT was unavailable) was compared with the CCT cohort with regard to the diagnosis or exclusion of CAD at 3 months post-discharge from hospital.

RESULTS

Of 198 patients admitted, 98 were identified as eligible for CCT. Of these, 37 were recommended for alternative management on cardiologist review, 18 declined consent, 23 were unable to be scanned within 24 h prior to discharge and 14 underwent CCT. CAD was diagnosed or excluded in 14/14 patients undergoing CCT. CAD was diagnosed or excluded in 11/14 patients investigated without CCT, leaving 3/14 patients with no clear diagnosis.

CONCLUSION

This study suggests nurses may be trained to assess patients for CCT within agreed protocols. In the UK it is likely these protocols will be based on NICE guidance. Despite potential diagnostic utility, CCT appears likely to form a small percentage of cardiac investigations undertaken.

Cost-effectiveness of point-of-care biomarker assessment for suspected myocardial infarction: the randomized assessment of treatment using panel Assay of cardiac markers (RATPAC) trial

OBJECTIVES

Chest pain due to suspected myocardial infarction (MI) is responsible for many hospital admissions and consumes substantial health care resources. The Randomized Assessment of Treatment using Panel Assay of Cardiac markers (RATPAC) trial showed that diagnostic assessment using a point-of-care (POC) cardiac biomarker panel consisting of CK-MB, myoglobin, and troponin increased the proportion of patients successfully discharged after emergency department (ED) assessment. In this economic analysis, the authors aimed to determine whether POC biomarker panel assessment reduced health care costs and was likely to be cost-effective.

METHODS

The RATPAC trial was a multicenter individual patient randomized controlled trial comparing diagnostic assessment using a POC biomarker panel (CK-MB, myoglobin, and troponin, measured at baseline and 90 minutes) to standard care without the POC panel in patients attending six EDs with acute chest pain due to suspected MI (n = 2,243). Individual patient resource use data were collected from all participants up to 3 months after hospital attendance using self-completed questionnaires at 1 and 3 months and case note review. ED staff and POC testing costs were estimated through a microcosting study of 246 participants. Resource use was valued using national unit costs. Health utility was measured using the EQ-5D self-completed questionnaire, mailed at 1 and 3 months. Quality-adjusted life-years (QALYs) were calculated by the trapezium rule using the EQ-5D tariff values at all follow-up points. Mean costs per patient were compared between the two treatment groups. Cost-effectiveness was estimated in terms of probability of dominance and incremental cost per QALY.

RESULTS

Point-of-care panel assessment was associated with higher ED costs, coronary care costs, and cardiac intervention costs, but lower general inpatient costs. Mean costs per patient were £1217.14 (standard deviation [SD] ± 3164.93), or $1,987.14 (SD ±$4,939.25), with POC versus £1005.91 (SD ±£1907.55), or $1,568.64 (SD ±$2,975.78), with standard care (p = 0.056). Mean QALYs were 0.158 (SD ± 0.052) versus 0.161 (SD ± 0.056; p = 0.250). The probability of standard care being dominant (i.e., cheaper and more effective) was 0.888, while the probability of the POC panel being dominant was 0.004. These probabilities were not markedly altered by sensitivity analysis varying the costs of the POC panel and excluding intensive care costs.

CONCLUSIONS

Point-of-care panel assessment does not reduce costs despite reducing admissions and may even increase costs. It is unlikely to be considered a cost-effective use of health care resources.

Improving the safety of oxygen therapy in the treatment of acute myocardial infarctions

AIM

The article examines the evidence for giving oxygen routinely to patients with suspected myocardial infarction, and addresses the challenges in changing practice.

BACKGROUND

It has been thought that administering oxygen to patients suffering from acute myocardial infarctions may be beneficial, but there is a lack of supporting evidence. Furthermore there is evidence that the use of oxygen in some circumstances may not improve clinical outcome. Despite conflicting evidence, guidelines in the past have recommended supplementary oxygen as part of treatment. Therefore it was necessary to understand and identify best practice.

METHODS

Evidence was collated using electronic databases. Search terms included 'acute myocardial infarction' 'acute coronary syndrome' 'oxygen' and 'hypoxia', 'hyperoxaemia'.

CONCLUSION

A systematic review of studies did not confirm that the use of routine oxygen in the acute stages of a myocardial infarction reduces myocardial ischemia. In reality, some evidence suggests that oxygen may even increase myocardial ischemia. Therefore it is crucial that emergency care nurses/practitioners across the world use observation skills and monitoring such as pulse oximetry to recognise the clinical need for supplementary oxygen to be given to a patient.

A 2-h diagnostic protocol to assess patients with chest pain symptoms in the Asia-Pacific region (ASPECT): a prospective observational validation study

BACKGROUND

Patients with chest pain contribute substantially to emergency department attendances, lengthy hospital stay, and inpatient admissions. A reliable, reproducible, and fast process to identify patients presenting with chest pain who have a low short-term risk of a major adverse cardiac event is needed to facilitate early discharge. We aimed to prospectively validate the safety of a predefined 2-h accelerated diagnostic protocol (ADP) to assess patients presenting to the emergency department with chest pain symptoms suggestive of acute coronary syndrome.

METHODS

This observational study was undertaken in 14 emergency departments in nine countries in the Asia-Pacific region, in patients aged 18 years and older with at least 5 min of chest pain. The ADP included use of a structured pre-test probability scoring method (Thrombolysis in Myocardial Infarction [TIMI] score), electrocardiograph, and point-of-care biomarker panel of troponin, creatine kinase MB, and myoglobin. The primary endpoint was major adverse cardiac events within 30 days after initial presentation (including initial hospital attendance). This trial is registered with the Australia-New Zealand Clinical Trials Registry, number ACTRN12609000283279.

FINDINGS

3582 consecutive patients were recruited and completed 30-day follow-up. 421 (11.8%) patients had a major adverse cardiac event. The ADP classified 352 (9.8%) patients as low risk and potentially suitable for early discharge. A major adverse cardiac event occurred in three (0.9%) of these patients, giving the ADP a sensitivity of 99.3% (95% CI 97.9-99.8), a negative predictive value of 99.1% (97.3-99.8), and a specificity of 11.0% (10.0-12.2).

INTERPRETATION

This novel ADP identifies patients at very low risk of a short-term major adverse cardiac event who might be suitable for early discharge. Such an approach could be used to decrease the overall observation periods and admissions for chest pain. The components needed for the implementation of this strategy are widely available. The ADP has the potential to affect health-service delivery worldwide.

FUNDING

Alere Medical (all countries), Queensland Emergency Medicine Research Foundation and National Health and Medical Research Council (Australia), Christchurch Cardio-Endocrine Research Group (New Zealand), Medquest Jaya Global (Indonesia), Science International (Hong Kong), Bio Laboratories Pte (Singapore), National Heart Foundation of New Zealand, and Progressive Group (Taiwan).

Diagnostic accuracy of heart-type fatty acid-binding protein for the early diagnosis of acute myocardial infarction

OBJECTIVE

The aim of this study was to evaluate the diagnostic efficacy of multiple tests-heart-type fatty acid-binding protein (H-FABP), cardiac troponin I (cTnI), creatine kinase-MB, and myoglobin-for the early detection of acute myocardial infarction among patients who present to the emergency department with chest pain.

METHODS

A total of 1128 patients provided a total of 2924 venous blood samples. Patients with chest pain were nonselected and treated according to hospital guidelines. Additional cardiac biomarkers were assayed simultaneously at serial time points using the Cardiac Array (Randox Laboratories Ltd, Crumlin, United Kingdom).

RESULTS

Heart-type fatty acid-binding protein had the greatest sensitivity at 0 to 3 hours (64.3%) and 3 to 6 hours (85.3%) after chest pain onset. The combination of cTnI measurement with H-FABP increased sensitivity to 71.4% at 3 to 6 hours and 88.2% at 3 to 6 hours. Receiver operating characteristic curves demonstrated that H-FABP had the greatest diagnostic ability with area under the curve at 0 to 3 hours of 0.841 and 3 to 6 hours of 0.894. The specificity was also high for the combination of H-FABP with cTnI at these time points. Heart-type fatty acid-binding protein had the highest negative predictive values of all the individual markers: 0 to 3 hours (93%) and 3 to 6 hours (97%). Again, the combined measurement of cTnI with H-FABP increased the negative predictive values to 94% at 0 to 3 hours, 98% at 3 to 6 hours, and 99% at 6 to 12 hours.

CONCLUSION

Testing both H-FABP and cTnI using the Cardiac Array proved to be both a reliable diagnostic tool for the early diagnosis of myocardial infarction/acute coronary syndrome and also a valuable rule-out test for patients presenting at 3 to 6 hours after chest pain onset.