Diagnostic accuracy of point-of-care testing for acute coronary syndromes, heart failure and thromboembolic events in primary care: a cluster-randomised controlled trial

An update of new/potential cardiovascular markers: a narrative review

BACKGROUND

Cardiovascular and their associated disease (CVD) is a leading cause of death worldwide, in developed and developing countries, and its prevalence has increased over the past few decades, due to changes in the lifestyle of people. Biomarkers are important tools for diagnosing, analyzing, and providing evidence of pathological conditions of CVD and their associated diseases.

METHODS

This study reviews historical cardiovascular biomarkers used to diagnose various diseases, their uses, and limitations, as well as the importance of new and emerging biomarkers.

CONCLUSION

sST2, GDF-15, CD-40, IL-6, and Micro-RNA. Initial studies of the future of cardiac biomarkers are promising, but more research is needed to demonstrate that they are more effective biomarkers of risk factors for CVD development. They also lack the analytical foundation needed for adoption in the medical industry. It is also necessary to determine whether these biomarkers can be used for diagnosis.

Cardiac troponin measurement at the point of care: educational recommendations on analytical and clinical aspects by the IFCC Committee on Clinical Applications of Cardiac Bio-Markers (IFCC C-CB)

The International Federation of Clinical Chemistry and Laboarator Medicine (IFCC) Committee on Clinical Applications of Cardiac Bio-Markers (C-CB) has provided evidence-based educational resources to aid and improve the understanding of important analytical and clinical aspects of cardiac biomarkers. The present IFCC C-CB educational report focuses on recommendations for appropriate use, analytical performance, and gaps in clinical studies related to the use of cardiac troponin (cTn) by point of care (POC) measurement, often referred to as a point of care testing (POCT). The use of high-sensitivity (hs)-cTn POC devices in accelerated diagnostic protocols used in emergency departments or outpatient clinics investigating acute coronary syndrome has the potential for improved efficacy, reduction of length of stay and reduced costs in the health care system. POCT workflow integration includes location of the instrument, assignment of collection and testing responsibility to (non-lab) staff, instrument maintenance, in-service and recurrent training, quality control, proficiency assessments, discrepant result trapping, and troubleshooting and inventory management.

Diagnostic Modalities in Critical Care: Point-of-Care Approach

The concept of intensive care units (ICU) has existed for almost 70 years, with outstanding development progress in the last decades. Multidisciplinary care of critically ill patients has become an integral part of every modern health care system, ensuing improved care and reduced mortality. Early recognition of severe medical and surgical illnesses, advanced prehospital care and organized immediate care in trauma centres led to a rise of ICU patients. Due to the underlying disease and its need for complex mechanical support for monitoring and treatment, it is often necessary to facilitate bed-side diagnostics. Immediate diagnostics are essential for a successful treatment of life threatening conditions, early recognition of complications and good quality of care. Management of ICU patients is incomprehensible without continuous and sophisticated monitoring, bedside ultrasonography, diverse radiologic diagnostics, blood gas analysis, coagulation and blood management, laboratory and other point-of-care (POC) diagnostic modalities. Moreover, in the time of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, particular attention is given to the POC diagnostic techniques due to additional concerns related to the risk of infection transmission, patient and healthcare workers safety and potential adverse events due to patient relocation. This review summarizes the most actual information on possible diagnostic modalities in critical care, with a special focus on the importance of point-of-care approach in the laboratory monitoring and imaging procedures.

Point-of-care testing of (N-terminal pro) B-type natriuretic peptide for heart disease patients in home care and ambulatory care settings

Objectives

The role of point-of-care testing (POCT) out of hospital, especially in home care and ambulatory care settings, is an issue meriting further research. We reviewed studies reporting cardiovascular events as a result of the implementation of B-type natriuretic peptide or N-terminal pro B-type natriuretic peptide POCT (BNP/NT-proBNP POCT) for heart disease patients in the settings.

Design

Articles were searched via a PubMed engine until May 30, 2020.

Results

In total, six studies were selected. Three studies involving ambulatory care used the POCT to refer patients with suspected heart diseases to a specialist. The other three used the tests in home care to monitor patients with heart failure. In ambulatory care, the randomized controlled trials, in which referrals were made to a specialist, showed that the group using POCT had significantly fewer cardiovascular outcomes, such as hospitalizations and deaths, than the non-use group. In home care, adverse outcomes were predicted from changes in BNP levels.

Conclusions

In most studies, the use of BNP/NT-proBNP POCT in home care and ambulatory care settings demonstrated favorable results regarding the cardiovascular outcomes. The utility of POCT in the settings is suggested, while more investigations are required.

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Point-of-care testing of BNP can be useful for referral of patients to specialists as demonstrated in two randomized control trials.

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Point-of-care testing of BNP couldpredict acute heart failure as demonstrated in three observational studies.

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The findings should be generalized with care because of the limitation of available data.

Cardiac biomarker measurement by point of care testing - Development, rationale, current state and future developments

Cardiac biomarker measurements are integral to the diagnosis and management of patients presenting with breathlessness and chest pain. Measurement of B type natriuretic peptide either directly or of the N-terminal portion of the prohormone although possible by point of care testing (POCT) has largely become a laboratory test. Measurement of the cardiac troponins cardiac troponin T (cTnT) and cardiac troponin I (cTnI) can easily and accurately be performed by POCT. The situation has been complicated by the development of high sensitivity assays for cTnT and cTnI and the subsequent development of rapid rule out algorithms allowing patient categorisation and discharge on admission and 1 to 2 h following admission. This article reviews the development of POCT for cardiac biomarkers, the evidence base comparing POCT with central laboratory testing, its strengths and limitations, and how POCT fits into the world of high sensitivity troponin assays. It also discusses what evidence there is that POCT can form part of rapid decision-making strategies and how this applies in an era of algorithms based on and is derived from measurement of high sensitivity troponin in the central laboratory.

BNP/NT-proBNP in pulmonary arterial hypertension: time for point-of-care testing?

Despite the advent of new therapies and improved outcomes in patients with pulmonary arterial hypertension (PAH), it remains a life-shortening disease and the time to diagnosis remains unchanged. Strategies to improve outcomes are therefore currently focused on earlier diagnosis and a treatment approach aimed at moving patients with PAH into a category of low-risk of 1-year mortality. B-type natriuretic peptide (BNP; or brain natriuretic peptide) and N-terminal prohormone of BNP (NT-proBNP) are released from cardiac myocytes in response to mechanical load and wall stress. Elevated levels of BNP and NT-proBNP are incorporated into several PAH risk stratification tools and screening algorithms to aid diagnosis of systemic sclerosis. We have undertaken a systematic review of the literature with respect to the use of BNP and NT-proBNP in PAH and the use of these biomarkers in the diagnosis and risk stratification of PAH, their relation to pulmonary haemodynamics and the potential for point-of-care testing to improve diagnosis and prognosis.

Cardiac biomarkers by point-of-care testing – back to the future?

The measurement of the cardiac troponins (cTn), cardiac troponin T (cTnT) and cardiac troponin I (cTnI) are integral to the management of patients with suspected acute coronary syndromes (ACS). Patients without clear electrocardiographic evidence of myocardial infarction require measurement of cTnT or cTnI. It therefore follows that a rapid turnaround time (TAT) combined with the immediacy of results return which is achieved by point-of-care testing (POCT) offers a substantial clinical benefit. Rapid results return plus immediate decision-making should translate into improved patient flow and improved therapeutic decision-making. The development of high sensitivity troponin assays offer significant clinical advantages. Diagnostic algorithms have been devised utilising very low cut-offs at first presentation and rapid sequential measurements based on admission and 3 h sampling, most recently with admission and 1 h sampling. Such troponin algorithms would be even more ideally suited to point-of-care testing as the TAT achieved by the diagnostic laboratory of typically 60 min corresponds to the sampling interval required by the clinician using the algorithm. However, the limits of detection and analytical imprecision required to utilise these algorithms is not yet met by any easy-to-use POCT systems.

Optimising standards of care of heart failure in general practice the OSCAR-HF pilot study protocol

Background: Heart failure (HF) imposes a burden for patients and health economics. General practitioners (GPs) are confronted with the broadest range of HF management. Although guidelines exist, they are not fully implemented in the Belgian health care system. Methods: We will conduct a non-randomised, non-controlled prospective observational trial (six months follow-up) to implement a multifaceted intervention in Belgian general practice to support GPs in the implementation of evidence-based HF guidelines. The multifaceted intervention consists of an audit and feedback method to detect previously unrecognised patients with HF and to increase awareness for proactive HF management, an NT-proBNP point-of-care test to improve detection and adequate diagnosis of patients with HF and a specialist HF nurse to assist GPs in the education of patients, optimisation of treatment and follow-up after hospitalisation. All patients aged 40 years and older with a confirmed diagnosis of HF by their GP based on the clinical audit are eligible for participation. The main objective of this pilot study is to evaluate the feasibility of this multifaceted intervention and the evolution of predefined quality indicators. We will measure the impact on HF diagnosis, medication optimisation, multidisciplinary follow-up and patients' quality of life after six months. Additionally, the experiences of GPs and investigators will be studied. Conclusions: Heart failure is an important health problem in which GPs play a key role. Therefore, we will evaluate the feasibility of a multifaceted intervention to optimise diagnosis as well as implement the guideline recommended therapies in patients with HF in general practice.

Chest pain in general practice: a systematic review of prediction rules

OBJECTIVE

To identify and assess the performance of clinical decision rules (CDR) for chest pain in general practice.

DESIGN

Systematic review of diagnostic studies.

DATA SOURCES

Medline/Pubmed, Embase/Ovid, CINAHL/EBSCO and Google Scholar up to October 2018.

STUDY SELECTION

Studies that assessed CDRs for intermittent-type chest pain and for rule out of acute coronary syndrome (ACS) applicable in general practice, thus not relying on advanced laboratory, computer or diagnostic testing.

REVIEW METHODS

Reviewers identified studies, extracted data and assessed the quality of the evidence (using Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2)), independently and in duplicate.

RESULTS

Eight studies comprising five CDRs met the inclusion criteria. Three CDRs are designed for rule out of coronary disease in intermittent-type chest pain (Gencer rule, Marburg Heart Score, INTERCHEST), and two for rule out of ACS (Grijseels rule, Bruins Slot rule). Studies that examined the Marburg Heart Score had the highest methodological quality with consistent sensitivity (86%-91%), specificity (61%-81%) and positive (23%-35%) and negative (97%-98%) predictive values (PPV and NPV). The diagnostic performance of Gencer (PPV: 20%-34%, NPV: 95%-99%) and INTERCHEST (PPV: 35%-43%, NPV: 96%-98%) appear comparable, but requires further validation. The Marburg Heart Score was more sensitive in detecting coronary disease than the clinical judgement of the general practitioner. The performance of CDRs that focused on rule out of ACS were: Grijseels rule (sensitivity: 91%, specificity: 37%, PPV: 57%, NPV: 82%) and Bruins Slot (sensitivity: 97%, specificity: 10%, PPV: 23%, NPV: 92%). Compared with clinical judgement, the Bruins Slot rule appeared to be safer than clinical judgement alone, but the study was limited in sample size.

CONCLUSIONS

In general practice, there is currently no clinical decision aid that can safely rule out ACS. For intermittent chest pain, several rules exist, of which the Marburg Heart Score has been most extensively tested and appears to outperform clinical judgement alone.

The conundrum of acute chest pain in general practice: a nationwide survey in The Netherlands

Background

GPs are frequently confronted with patients with acute onset chest pain. Although usually benign, approximately 5% is due to acute coronary syndrome (ACS). Unfortunately, ACS is not always recognised, leading to a missed diagnosis in 2–5% of presentations.

Aim

The authors set out to study the level of risk GPs are willing to accept with regards to missing an ACS diagnosis, and the receptiveness of implementing new clinical decision aids.

Design & setting

This study involved an online survey among GPs in the Netherlands.

Method

A concept survey was constructed, which was tested among a panel of 24 GPs. The survey was then modified to achieve content validity. This survey was electronically distributed among 1000 GPs.

Results

A total of 313 (31.3%) GPs completed the survey. Of those surveyed, the median age was 50 years (interquartile range 41–57), 53.0% were female, and 6.4% were specialist GPs ('kaderarts') in cardiology or acute care. GPs estimated the missed ACS rate to be <5.0% in clinical practice, most often estimating a chance of 1.0–2.5% (35.2%) or 0.5–1.0% (29.7%). For atypical case presentations, 70% of GPs would accept a 0.1–1.0% missed diagnosis rate, while keeping the referral threshold to a maximum of 50 unnecessary referrals for each ACS case (75% of responders). GPs would welcome additional decision aids, with 79.2% favouring a clinical decision aid, 77.1% favouring troponin point-of-care (POC) testing, and 85.5% favoring a combination of a clinical decision aid and a troponin POC test.

Conclusion

GPs perceive that they miss more ACS cases than they feel comfortable with, which is reflected in a defensive referral strategy. The vast majority of GPs would welcome the use of clinical decision aids and/or cardiac biomarker POC testing for ruling out ACS, if accompanied by more certainty than based on clinical judgment alone.

Diagnostic accuracy of point-of-care natriuretic peptide testing for chronic heart failure in ambulatory care: systematic review and meta-analysis

OBJECTIVE

To assess the diagnostic accuracy of point-of-care natriuretic peptide tests in patients with chronic heart failure, with a focus on the ambulatory care setting.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Ovid Medline, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, Embase, Health Technology Assessment Database, Science Citation Index, and Conference Proceedings Citation Index until 31 March 2017.

STUDY SELECTION

Eligible studies evaluated point-of-care natriuretic peptide testing (B-type natriuretic peptide (BNP) or N terminal fragment pro B-type natriuretic peptide (NTproBNP)) against any relevant reference standard, including echocardiography, clinical examination, or combinations of these, in humans. Studies were excluded if reported data were insufficient to construct 2×2 tables. No language restrictions were applied.

RESULTS

42 publications of 39 individual studies met the inclusion criteria and 40 publications of 37 studies were included in the analysis. Of the 37 studies, 30 evaluated BNP point-of-care testing and seven evaluated NTproBNP testing. 15 studies were done in ambulatory care settings in populations with a low prevalence of chronic heart failure. Five studies were done in primary care. At thresholds >100 pg/mL, the sensitivity of BNP, measured with the point-of-care index device Triage, was generally high and was 0.95 (95% confidence interval 0.90 to 0.98) at 100 pg/mL. At thresholds <100 pg/mL, sensitivity ranged from 0.46 to 0.97 and specificity from 0.31 to 0.98. Primary care studies that used NTproBNP testing reported a sensitivity of 0.99 (0.57 to 1.00) and specificity of 0.60 (0.44 to 0.74) at 135 pg/mL. No statistically significant difference in diagnostic accuracy was found between point-of-care BNP and NTproBNP tests.

CONCLUSIONS

Given the lack of studies in primary care, the paucity of NTproBNP data, and potential methodological limitations in these studies, large scale trials in primary care are needed to assess the role of point-of-care natriuretic peptide testing and clarify appropriate thresholds to improve care of patients with suspected or chronic heart failure.

Point-of-care testing in primary care patients with acute cardiopulmonary symptoms: a systematic review

BACKGROUND

Point-of-care tests (POCT) can assist general practitioners (GPs) in diagnosing and treating patients with acute cardiopulmonary symptoms, but it is currently unknown if POCT impact relevant clinical outcomes in these patients.

OBJECTIVE

To assess whether using POCT in primary care patients with acute cardiopulmonary symptoms leads to more accurate diagnosis and impacts clinical management.

METHODS

We performed a systematic review in four bibliographic databases. Articles published before February 2016 were screened by two reviewers. Studies evaluating the effect of GP use of POCT on clinical diagnostic accuracy and/or effect on treatment and referral rate in patients with cardiopulmonary symptoms were included.

RESULTS

Our search yielded nine papers describing data from seven studies, on the clinical diagnostic accuracy of POCT in a total of 2277 primary care patients with acute cardiopulmonary symptoms. Four papers showed data on GP use of D-dimer POCT in pulmonary embolism (two studies); two studies on Troponin T in acute coronary syndrome; one on heart-type fatty acid-binding protein (H-FABP) in acute coronary syndrome; one on B-type natriuretic peptide (BNP) in heart failure; one on 3-in-1 POCT (Troponin T, BNP, D-dimer) in acute coronary syndrome, heart failure and/or pulmonary embolism. Only one study assessed the effect of GP use of POCT on treatment initiation and one on actual referral rates.

CONCLUSION

There is currently limited and inconclusive evidence that actual GP use of POCT in primary care patients with acute cardiopulmonary symptoms leads to more accurate diagnosis and affects clinical management. However, some studies show promising results, especially when a POCT is combined with a clinical decision rule.

Accuracy, user-friendliness and usefulness of the Cobas h232 point-of-care test for NT-proBNP in primary care

Aims

N-terminal pro-B-type natriuretic peptide (NT-proBNP) has been shown to be useful for ruling out heart failure in primary care. In this study, we examined the accuracy of the Cobas h232 point-of-care (POC) instrument in primary care compared with an in-hospital measurement. Furthermore, we investigated the user-friendliness and usefulness of the POC device.

Methods

Five general practitioner (GP) groups were asked to evaluate adult patients who were suspected of having heart failure and to test NT-proBNP with the Cobas h232. The samples were subsequently delivered to and analysed at a central hospital laboratory by the Cobas e602 using conventional transport and storage. Difference between the paired measurements was analysed using a percentage difference plot, and correlation was assessed using Passing-Bablok linear regression analysis. User-friendliness and usefulness were assessed using semistructured questionnaires.

Results

Nineteen GPs studied 94 patients. Passing-Bablok analysis showed a slope of 1.05 (95% CI 1.00 to 1.11) (R2=0.97). The percentage difference plot showed a mean difference of 15.7% (95% CI −46.0% to –77.4%). User-friendliness and usefulness had median scores of 4 or 5 on a five-point Likert scale. Eighteen out of 19 GPs confirmed that the device influenced their clinical practice. During the study, GPs’ confidence in using NT-proBNP increased significantly from a mean score of 4.4 (95% CI 3.2 to 5.6) to 7.6 out of 10 (95% CI 7.1 to 8.2).

Conclusions

The Cobas h232 NT-proBNP POC test proved to be an accurate, user-friendly and useful test in primary care. Nearly all participating GPs were convinced that the test could benefit clinical decision making.

A systematic evaluation of immunoassay point-of-care testing to define impact on patients' outcomes

Background Point-of-care testing has been developed to provide rapid test results. Most published studies focus on analytical performance, neglecting its impact on patient outcomes. Objective To review the analytical performance and accuracy of point-of-care testing specifically planned for immunoassay and to evaluate the impact of faster results on patient management. Methods A search of electronic databases for studies reporting immunoassay results obtained in both point-of-care testing and central laboratory scenarios was performed. Data were extracted concerning the study details, and the methodological quality was assessed. The analytical characteristics and diagnostic accuracy of six points-of-care testing: troponin, procalcitonin, parathyroid hormone, brain natriuretic peptide, C-reactive protein and neutrophil gelatinase-associated lipocalin were evaluated. Results A total of 116 scientific papers were analysed. Studies measuring procalcitonin, parathyroid hormone and neutrophil gelatinase-associated lipocalin reported a limited impact on diagnostic decisions. Seven studies measuring C-reactive protein claimed a significant reduction of antibiotic prescription. Several authors evaluated brain natriuretic peptide or troponin reporting faster decision-making without any improvement in clinical outcome. Forty-four per cent of studies reported analytical data, showing satisfactory correlations between results obtained through point-of-care testing and central laboratory setting. Half of studies defined the diagnostic accuracy of point-of-care testing as acceptable for troponin (median sensitivity and specificity: 74% and 94%, respectively), brain natriuretic peptide (median sensitivity and specificity: 82% and 88%, respectively) and C-reactive protein (median sensitivity and specificity 85%). Conclusions Point-of-care testing immunoassay results seem to be reliable and accurate for troponin, brain natriuretic peptide and C-reactive protein. The satisfactory analytical performance, together with an excellent practicability, suggests that it could be a consistent tool in clinical practice, but data are lacking regarding the patient outcomes.

Improving early exclusion of acute coronary syndrome in primary care: the added value of point-of-care troponin as stated by general practitioners

Aim To investigate general practitioners' (GPs') desire and perceived added value of point-of-care (POC) troponin, its effect on referral decisions, and test requirements.

BACKGROUND

Excluding acute coronary syndrome (ACS) in primary care remains a diagnostic challenges for GPs. Consequently, referral rates of chest pain patients are high, while the incidence of a cardiovascular problem is only 8-15%. Previous studies have shown that GPs are interested in a POC troponin test. This test could enhance rapid exclusion of ACS, thereby preventing unnecessary patient distress, without compromising safety and while reducing costs. However, using this test is not recommended in current guidelines due to uncertainty in the test's potential added value, and the lower sensitivity early after symptom onset as compared with troponin tests in a regular laboratory.

METHODS

An online survey containing 34 questions was distributed among 837 Dutch GPs in June 2015. Findings A total of 126 GPs (15.1%) completed at least 75% of the questions. 67.1% of GPs believe that POC troponin tests have moderate to very high added value. Although the availability of a POC test is expected to increase the frequency at which troponin tests are used, it likely decreases (immediate) referral rates. Of the responding GPs, 78.3% only accept 10 min as the maximum test duration, 78.1% think reimbursement of the POC device is required for implementation, and 68.9% consider it necessary that it can be performed with a finger prick blood sample. In conclusion, according to GPs, the POC troponin test can be of added value to exclude ACS early on. Actual test implementation will depend on test characteristics, including test duration, type of blood sample required, and reimbursement of the analyzer.

Evidence for models of diagnostic service provision in the community: literature mapping exercise and focused rapid reviews

Background

Current NHS policy favours the expansion of diagnostic testing services in community and primary care settings.

Objectives

Our objectives were to identify current models of community diagnostic services in the UK and internationally and to assess the evidence for quality, safety and clinical effectiveness of such services. We were also interested in whether or not there is any evidence to support a broader range of diagnostic tests being provided in the community.

Review methods

We performed an initial broad literature mapping exercise to assess the quantity and nature of the published research evidence. The results were used to inform selection of three areas for investigation in more detail. We chose to perform focused reviews on logistics of diagnostic modalities in primary care (because the relevant issues differ widely between different types of test); diagnostic ultrasound (a key diagnostic technology affected by developments in equipment); and a diagnostic pathway (assessment of breathlessness) typically delivered wholly or partly in primary care/community settings. Databases and other sources searched, and search dates, were decided individually for each review. Quantitative and qualitative systematic reviews and primary studies of any design were eligible for inclusion.

Results

We identified seven main models of service that are delivered in primary care/community settings and in most cases with the possible involvement of community/primary care staff. Not all of these models are relevant to all types of diagnostic test. Overall, the evidence base for community- and primary care-based diagnostic services was limited, with very few controlled studies comparing different models of service. We found evidence from different settings that these services can reduce referrals to secondary care and allow more patients to be managed in primary care, but the quality of the research was generally poor. Evidence on the quality (including diagnostic accuracy and appropriateness of test ordering) and safety of such services was mixed.

Conclusions

In the absence of clear evidence of superior clinical effectiveness and cost-effectiveness, the expansion of community-based services appears to be driven by other factors. These include policies to encourage moving services out of hospitals; the promise of reduced waiting times for diagnosis; the availability of a wider range of suitable tests and/or cheaper, more user-friendly equipment; and the ability of commercial providers to bid for NHS contracts. However, service development also faces a number of barriers, including issues related to staffing, training, governance and quality control.

Limitations

We have not attempted to cover all types of diagnostic technology in equal depth. Time and staff resources constrained our ability to carry out review processes in duplicate. Research in this field is limited by the difficulty of obtaining, from publicly available sources, up-to-date information about what models of service are commissioned, where and from which providers.

Future work

There is a need for research to compare the outcomes of different service models using robust study designs. Comparisons of ‘true’ community-based services with secondary care-based open-access services and rapid access clinics would be particularly valuable. There are specific needs for economic evaluations and for studies that incorporate effects on the wider health system. There appears to be no easy way of identifying what services are being commissioned from whom and keeping up with local evaluations of new services, suggesting a need to improve the availability of information in this area.

Funding

The National Institute for Health Research Health Services and Delivery Research programme.

Consequences of high-sensitivity troponin T testing applied in a primary care population with chest pain compared with a commercially available point-of-care troponin T analysis: an observational prospective study

Background

There is a demand for a highly sensitive and specific point-of care test to detect acute myocardial infarction (AMI). It is unclear if a high-sensitivity troponin assay will have enough discriminative power to become a decision support in primary care. The aim of this study was to evaluate a high-sensitivity troponin T assay performed in three primary health care centres in southeast Sweden and to compare the outcome with a point-of-care troponin T test.

Methods

This study included 115 patients who consulted their general practitioner for chest pain, dyspnoea on exertion, unexplained weakness and/or fatigue in the last 7 days. Troponin T was analysed by a point-of-care test and a high-sensitivity method together with N-terminal pro-B-type natriuretic peptide (NT-proBNP) and creatinine. All patients were checked for AMI or unstable angina (UA) within 30 days of study enrolment. Univariate and multivariate logistic regression was carried out to examine possible connections between troponin T ≥ 15 ng/L, clinical variables and laboratory findings at baseline. In addition, 21 patients with troponin T ≥ 15 ng/L and no signs of AMI or UA were followed up for 2–3 years.

Results

Three patients were diagnosed with AMI and three with UA. At the ≥ 15 ng/L cut-off, the troponin T method had 100% sensitivity, 75% specificity for AMI and a positive predictive value of 10%. The troponin T point-of-care test missed one case of AMI and the detection limit was 50 ng/L. Troponin T ≥ 15 ng/L was correlated to age ≥65 years (odds ratio (OR), 10.9 95% CI 2.28–51.8) and NT-proBNP in accordance with heart failure (OR 8.62 95% CI 1.61–46.1). Fourteen of the 21 patients, without signs of AMI or UA at baseline, still had increased troponin T at follow-up after 2–3 years.

Conclusions

A high-sensitivity troponin T assay could become useful in primary care as a point-of-care test for patients <65 years. For patients older than 65–70 years, a higher decision limit than ≥15 ng/L should be considered and used in conjunction with clinical parameters and possibly with NT-proBNP.

The value of signs, symptoms and plasma heart-type fatty acid-binding protein (H-FABP) in evaluating patients presenting with symptoms possibly matching acute coronary syndrome: background and methods of a diagnostic study in primary care

Background

Chest complaints presented to a general practitioner (GP) are frequently caused by diseases which have advantageous outcomes. However, in some cases, acute coronary syndrome (ACS) is present (1.5-22% of cases). The patient’s signs, symptoms and electrocardiography results are insufficient diagnostic tools to distinguish mild disease from ACS. Therefore, most patients presenting chest complaints are referred to secondary care facilities where ACS is then ruled out in a majority of patients (78%). Recently, a point of care test for heart-type fatty acid-binding protein (H-FABP) using a low cut-off value between positive and negative of 4 ng/ml has become available. We aim to study the role of this point of care device in triage of patients presenting chest complaints possibly due to ACS, in primary care. Our research protocol is presented in this article. Results are expected in 2015.

Methods/Design

Participating GPs will register signs and symptoms in all patients presenting chest complaints possibly due to ACS. Point of care H-FABP testing will also be performed. Our study will be a derivation study to identify signs and symptoms that, combined with point of care H-FABP testing, can be part of an algorithm to either confirm or rule out ACS. The diagnostic value for ACS of this algorithm in general practice will be determined.

Discussion

A safe diagnostic elimination of ACS by application of the algorithm can be of significant clinical relevance. Improved triage and thus reduction of the number of patients with chest complaints without underlying ACS, that are referred to secondary care facilities, could lead to a substantial cost reduction.

Trial registration

ClinicalTrials.gov, NCT01826994, accepted April 8^th 2013.

Cost consequences of point-of-care troponin T testing in a Swedish primary health care setting

OBJECTIVE

To evaluate the safety and cost-effectiveness of point-of-care troponin T testing (POCT-TnT) for the management of patients with chest pain in primary care.

DESIGN

Prospective observational study with follow-up.

SETTING

Three primary health care (PHC) centres using POCT-TnT and four PHC centres not using POCT-TnT in south-east Sweden.

PATIENTS

All patients ≥ 35 years of age, contacting one of the PHC centres for chest pain, dyspnoea on exertion, unexplained weakness and/or fatigue, with no other probable cause than cardiac, were included. Symptoms must have commenced or worsened during the previous seven days.

MAIN OUTCOME MEASURES

Emergency referral rates, diagnoses of acute myocardial infarction (AMI) or unstable angina (UA), and costs were collected for 30 days after the patient sought care at the PHC centre.

RESULTS

A total of 196 patients with chest pain were included: 128 in PHC centres with POCT-TnT and 68 in PHC centres without POCT-TnT. Fewer patients from the PHC centres with POCT-TnT (n = 32, 25%) were emergently referred to hospital than from centres without POCT-TnT (n = 29, 43%; p = 0.011). Eight patients (6.2%) from PHC centres with POCT-TnT were diagnosed with AMI or UA compared with six patients (8.8%) from centres without POCT-TnT (p = 0.565). Two patients with AMI or UA were classified as missed cases from PHC centres with POCT-TnT and there were no missed cases from PHC centres without POCT-TnT. SKr290 000 was saved per missed case of AMI or UA.

CONCLUSION

The use of POCT-TnT in primary care may be cost saving but at the expense of missed cases.

Point-of-care diagnostics, a major opportunity for change in traditional diagnostic approaches: potential and limitations

'Point-of-care' (POC) diagnostics are a powerful emerging healthcare approach. They can rapidly provide statistically significant results, are simple to use, do not require specialized equipment and are cost-effective. For these reasons, they have the potential to play a major role in revolutionizing the diagnosis, initiation and monitoring of treatment of major global diseases. This review focuses on antibody-based POC devices that target four major global diseases: cardiovascular diseases, prostate cancer, HIV infection and tuberculosis. The key statistics and pathology of each disease is described in detail, followed by an in-depth discussion on emerging POC devices that target each disease, highlighting their potential and limitations.

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.

NT-proBNP: A Guide to Improve the Management of Patients with Heart Failure

N-terminal prohormone of brain natriuretic peptide (NT-proBNP) is a versatile biomarker, that has been extensively studied in large cohorts of individuals in the general population, in subjects at risk for developing left ventricular dysfunction and cardiovascular events, and in patients with chronic or acutely decompensated heart failure (HF). In this paper, the pros and cons of using natriuretic peptide testing to manage patients with HF are presented and discussed over 3 broad areas: (1) dyspnea triage in the emergency room, (2) natriuretic peptide-guided treatment of chronic HF, and (3) management of patients with HF in primary care and nursing homes.

Measurement of natriuretic peptides at the point of care in the emergency and ambulatory setting: current status and future perspectives

The measurement of natriuretic peptides (NPs), B-type NP or N-terminal pro-B-type NP, can be an important tool in the diagnosis of acute heart failure in patients presenting to an Emergency Department (ED) with acute dyspnea, according to international guidelines. Studies and subsequent meta-analyses are mixed on the absolute value of routine NP assessment of ED patients. However, levels of NPs are likely to be used also to guide treatment and to assess risk of adverse outcomes in other patients at risk of developing heart failure, including those with pulmonary embolism or diabetes, or receiving chemotherapy. Natriuretic peptide levels, like other biomarkers, can now be measured at the point of care (POC). We have reviewed the current status of NP measurement together with the potential contribution of POC measurement of NPs to clinical care delivery in the emergency and other settings. Several POC systems for measuring NP levels are now available: these produce test results within 15 minutes and appear sufficiently sensitive and robust to be used routinely in diagnostic evaluations. Point-of-care systems could be used to assess NP levels in the ED and community outpatient settings to monitor the risk of acute heart failure. Furthermore, the use of protocol-driven POC testing of NP within the time frame of a patient consultation in the ED may facilitate and accelerate the throughput and disposition of at-risk patients. Appropriately designed clinical trials will be needed to confirm these potential benefits. It is also important that processes of care delivery are redesigned to take full advantage of the faster turnaround times provided by POC technology.

Agreement between self-reports and medical records of cardiovascular disease in octogenarians

OBJECTIVE

Self-reported health and disease status is a common method used in epidemiologic studies and surveys involving younger populations, but its reliability in octogenarians is unknown. The objective of the present study was to examine the level of agreement between self-reports and medical records on specific cardiovascular diagnoses.

STUDY DESIGN AND SETTING

The Life and Living to Advanced Age: a Cohort Study in New Zealand recruited 937 octogenarians in New Zealand. Standardized questionnaires were administered to determine sociodemographic status and medical history. Diagnoses of myocardial infarction (MI), stroke, congestive heart failure (CHF), and hypertension were compared between self-reports and two combined sources of medical records.

RESULTS

There were moderate levels of agreement between self-reports and medical records for MI, stroke, and hypertension (κ = 0.43-0.45) and low levels for CHF (κ = 0.19). The proportion of discordance for MI, stroke, CHF, and hypertension was 16%, 12%, 22%, and 27%, respectively. Adjusting for socioeconomic-demographic status and cognitive function, the number of comorbidities is highly associated with agreement between self-reports and medical records (P < 0.01). Gender, socioeconomic status, and cognitive function were also related to agreement between self-reports and medical records, but the strength of association was ethnic specific.

CONCLUSION

Self-reported information on specific cardiovascular conditions has only modest reliability in octogenarians and is associated with number of comorbidities.

Point-of-Care Troponin T Testing in the Management of Patients with Chest Pain in the Swedish Primary Care

Objective. To investigate the diagnostic accuracy and clinical benefit of point-of-care Troponin T testing (POCT-TnT) in the management of patients with chest pain. Design. Observational, prospective, cross-sectional study with followup. Setting. Three primary health care (PHC) centres using POCT-TnT and four PHC centres not using POCT-TnT in the southeast of Sweden. Patients. All patients ≥35 years old, contacting one of the primary health care centres for chest pain, dyspnoea on exertion, unexplained weakness, and/or fatigue with no other probable cause than cardiac, were included. Symptoms should have commenced or worsened during the last seven days. Main Outcome Measures. Emergency referrals, patients with acute myocardial infarctions (AMI), or unstable angina (UA) within 30 days of study enrolment. Results. 25% of the patients from PHC centres with POCT-TnT and 43% from PHC centres without POCT-TnT were emergently referred by the GP (P = 0.011 ). Seven patients (5.5%) from PHC centres with POCT-TnT and six (8.8%) from PHC centres without POCT-TnT were diagnosed as AMI or UA (P = 0.369). Two patients with AMI or UA from PHC centres with POCT-TnT were judged as missed cases in primary health care. Conclusion. The use of POCT-TnT may reduce emergency referrals but probably at the cost of an increased risk to miss patients with AMI or UA.

Measurement of the new anticoagulants

New oral anticoagulants are given at fixed daily doses without laboratory dose adjustment for prevention of venous thromboembolism following elective total knee- and hip replacement, for treatment and prevention of recurrent events of acute venous thromboembolism, and for prevention of embolic events in atrial fibrillation. However, it may be necessary to determine the anticoagulant effect of new oral anticoagulants in special patient populations such as in elderly, for renal impairment, before operation, bleeding or thrombotic episodes and to monitor self-compliance. Oral factor Xa and oral thrombin inhibitors influence dose dependently global and specific coagulation assays. Standardization of assays is currently undertaken. Determination of the new oral anticoagulants in serum samples would facilitate blood sampling and analysis from samples taken and stored for creatinine or other biochemical parameters. Point of care methods from plasma or urine for the new oral anticoagulants would improve patient care. First data demonstrate the feasibility of such assays in urine.