Is it safe to discharge patients from accident and emergency using a rapid point of care Triple Cardiac Marker test to rule out acute coronary syndrome in low to intermediate risk patients presenting with chest pain?

A tandem giant magnetoresistance assay for one-shot quantification of clinically relevant concentrations of N-terminal pro-B-type natriuretic peptide in human blood

We report a microfluidic sandwich immunoassay constructed around a dual-giant magnetoresistance (GMR) sensor array to quantify the heart failure biomarker NT-proBNP in human plasma at the clinically relevant concentration levels between 15 pg/mL and 40 ng/mL. The broad dynamic range was achieved by differential coating of two identical GMR sensors operated in tandem, and combining two standard curves. The detection limit was determined as 5 pg/mL. The assay, involving 53 plasma samples from patients with different cardiovascular diseases, was validated against the Roche Cobas e411 analyzer. The salient features of this system are its wide concentration range, low detection limit, small sample volume requirement (50 μL), and the need for a short measurement time of 15 min, making it a prospective candidate for practical use in point of care analysis.

Complementary, alternative, and putative nontroponin biomarkers of acute coronary syndrome: new resources for future risk assessment calculators

Biomarkers, other than cardiac troponin, with potential sensitivity and selectivity that provide diagnostic and prognostic insights into the tissue-specific injury processes underlying acute coronary syndrome and their possible use in risk stratification algorithms are discussed. Such biomarkers may be useful as complementary or alternative to cardiac troponin (I or T) assays in early diagnosis of acute coronary syndrome, as well as for monitoring acute coronary syndrome progression and prognosis assessment. The information included in this article is based on a critical analysis of selected published biomedical literature accessible through the United States National Library of Medicine's MEDLINE-PubMed and Scopus search engines. The majority of articles cited in this review and perspective, except for a few historical publications as background, were published between January 2000 and December 2013.

A 2-hour thrombolysis in myocardial infarction score outperforms other risk stratification tools in patients presenting with possible acute coronary syndromes: comparison of chest pain risk stratification tools

BACKGROUND

Accelerated diagnostic pathways for risk stratification of patients presenting to the emergency department with potential acute coronary syndromes may identify very-low-risk patients safe for early discharge to outpatient care.

METHODS

Patients presenting with potential acute coronary syndrome to the emergency department were prospectively enrolled between November 2007 and April 2010. Patient characteristics in conjunction with 0- and 2-hour biomarkers and electrocardiograms were analyzed according to a 2-hour thrombolysis in myocardial infarction (TIMI) score and 9 other accelerated diagnostic pathways. The primary outcome was acute coronary syndrome by 30 days.

RESULTS

Of 1,000 patients, 362 (36.2%) had a primary outcome. A pathway comprising electrocardiogram, prior ischemic heart disease, 0/2-hour troponin/creatine kinase MB fraction/myoglobin identified the highest proportion (25.0%) as low risk, with 96.1% sensitivity for the primary outcome. A pathway comprising electrocardiogram, history of ischemic heart disease, typical vs atypical symptoms, 0/2-hour troponin was the safest, with 99.7% sensitivity for the primary outcome, but only 9.0% were low risk. A pathway comprising the TIMI score with 0/2-hour troponin and electrocardiograms identified 15.5% as low risk, with a sensitivity of 99.2% for the primary outcome. This compares with standard care in which none were for outpatient care but, 3.3% had a primary outcome postdischarge within 30 days.

CONCLUSION

In this relatively high-risk population, a 2-hour TIMI score safely identified significant numbers of patients suitable for early discharge to outpatient care.

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.

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.

Cardiac biomarkers in acute myocardial infarction

Each year, a large number of patients are seen in the Emergency Department with presentations necessitating investigation for possible acute myocardial infarction. Patients can be stratified by symptoms, risk factors and electrocardiogram results but cardiac biomarkers also have a prime role both diagnostically and prognostically. This review summarizes both the history of cardiac biomarkers as well as currently available (established and novel) assays. Cardiac troponin, our current "gold standard" biomarker criterion for the diagnosis of myocardial infarction has high sensitivity and specificity for this diagnosis and therapies instituted in patients with elevated troponin have been shown to influence outcomes. Other markers of myocardial necrosis, inflammation and neurohormonal activity have also been shown to have either diagnostic or prognostic utility, but none have been shown to be superior to troponin. The measurement of multiple biomarkers and the use of point of care markers may accelerate current diagnostic protocols for the assessment of such patients.

Future developments in chest pain diagnosis and management

Much of the focus of research on patients with chest pain is directed at technological advances in the diagnosis and management of acute coronary syndrome (ACS), pulmonary embolism (PE), and acute aortic dissection (AAD), despite there being no significant difference at 4 years as regards mortality, ongoing chest pain, and quality of life between patients presenting to the emergency department with noncardiac chest pain and those with cardiac chest pain. This article examines future developments in the diagnosis and management of patients with suspected ACS, PE, AAD, gastrointestinal disease, and musculoskeletal chest pain.