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

Robust semi-automated path extraction for visualising stenosis of the coronary arteries

Computed tomography angiography (CTA) is useful for diagnosing and planning treatment of heart disease. However, contrast agent in surrounding structures (such as the aorta and left ventricle) makes 3-D visualisation of the coronary arteries difficult. This paper presents a composite method employing segmentation and volume rendering to overcome this issue. A key contribution is a novel Fast Marching minimal path cost function for vessel centreline extraction. The resultant centreline is used to compute a measure of vessel lumen, which indicates the degree of stenosis (narrowing of a vessel). Two volume visualisation techniques are presented which utilise the segmented arteries and lumen measure. The system is evaluated and demonstrated using synthetic and clinically obtained datasets

Risk stratification in non-ST elevation acute coronary syndromes: risk scores, biomarkers and clinical judgment

Undifferentiated chest pain is one of the most common reasons for emergency department attendance and admission to hospitals. Non-ST elevation acute coronary syndrome (NSTE-ACS) is an important cause of chest pain, and accurate diagnosis and risk stratification in the emergency department must be a clinical priority. In the future, the incidence of NSTE-ACS will rise further as higher sensitivity troponin assays are implemented in clinical practice. In this article, we review contemporary approaches for the diagnosis and risk stratification of NSTE-ACS during emergency care. We consider the limitations of current practices and potential improvements. Clinical guidelines recommend an early invasive strategy in higher risk NSTE-ACS. The Global Registry of Acute Coronary Events (GRACE) risk score is a validated risk stratification tool which has incremental prognostic value for risk stratification compared with clinical assessment or troponin testing alone. In emergency medicine, there has been a limited adoption of the GRACE score in some countries (e.g. United Kingdom), in part related to a delay in obtaining timely blood biochemistry results. Age makes an exponential contribution to the GRACE score, and on an individual patient basis, the risk of younger patients with a flow-limiting culprit coronary artery lesion may be underestimated. The future incorporation of novel cardiac biomarkers into this diagnostic pathway may allow for earlier treatment stratification. The cost-effectiveness of the new diagnostic pathways based on high-sensitivity troponin and copeptin must also be established. Finally, diagnostic tests and risk scores may optimize patient care but they cannot replace patient-focused good clinical judgment

Cost-Sensitive Decision Trees with Completion Time Requirements

In many classification tasks, managing costs and completion times are the main concerns. In this paper, we assume that the completion time for classifying an instance is determined by its class label, and that a late penalty cost is incurred if the deadline is not met. This time requirement enriches the classification problem but posts a challenge to developing a solution algorithm. We propose an innovative approach for the decision tree induction, which produces multiple candidate trees by allowing more than one splitting attribute at each node. The user can specify the maximum number of candidate trees to control the computational efforts required to produce the final solution. In the tree-induction process, an allocation scheme is used to dynamically distribute the given number of candidate trees to splitting attributes according to their estimated contributions to cost reduction. The algorithm finds the final tree by backtracking. An extensive experiment shows that the algorithm outperforms the top-down heuristic and can effectively obtain the optimal or near-optimal decision trees without an excessive computation time.classification, decision tree, cost and time sensitive learning, late penalty

Advancing Physician Performance Measurement: Using Administrative Data to Assess Physician Quality and Efficiency

Summarizes national initiatives to advance the practice of standardized measurement and outlines goals for developing a method for tracking efficiency and quality that will reward physicians and enable patients to make informed healthcare choices

Computer aided diagnosis of coronary artery disease, myocardial infarction and carotid atherosclerosis using ultrasound images: a review

The diagnosis of Coronary Artery Disease (CAD), Myocardial Infarction (MI) and carotid atherosclerosis is of paramount importance, as these cardiovascular diseases may cause medical complications and large number of death. Ultrasound (US) is a widely used imaging modality, as it captures moving images and image features correlate well with results obtained from other imaging methods. Furthermore, US does not use ionizing radiation and it is economical when compared to other imaging modalities. However, reading US images takes time and the relationship between image and tissue composition is complex. Therefore, the diagnostic accuracy depends on both time taken to read the images and experience of the screening practitioner. Computer support tools can reduce the inter-operator variability with lower subject specific expertise, when appropriate processing methods are used. In the current review, we analysed automatic detection methods for the diagnosis of CAD, MI and carotid atherosclerosis based on thoracic and Intravascular Ultrasound (IVUS). We found that IVUS is more often used than thoracic US for CAD. But for MI and carotid atherosclerosis IVUS is still in the experimental stage. Furthermore, thoracic US is more often used than IVUS for computer aided diagnosis systems

Consensus statement on the use of high sensitivity cardiac troponins

The increased sensitivity of high sensitivity cardiac troponin assays comes at a cost of decreased specificity, and “false positive” diagnosis of acute coronary syndromes has made clinicians wary of their use, fearing unnecessary hospitalisations, angiography and revascularisation. The Ethics and Guidelines Standing Committee of SA Heart Association convened a meeting of cardiologists, chemical pathologists, emergency medicine specialists and industry representatives to discuss the role of high sensitivity troponin (hsTn) testing. An international expert provided guidance, and this Consensus Statement is the product of that meeting. It is recommended that hsTn assays be widely adopted as the preferred biomarker for diagnosis of myocardial infarction. Pathology laboratories will standardise the units of measurement and the reporting of results. Rules for interpretation of results and algorithms for their application are provided. Separate algorithms apply to troponin T and troponin I, and the several troponin I assays on the market each have different numerical values. Use of high sensitivity troponin assays will result in earlier diagnosis of myocardial infarction, more reliable ruling out of myocardial infarction, and shortening of chest pain triage (to 4 hours), compared to former assays

Screening for familial hypercholesterolaemia in primary care: Time for general practice to play its part

Fifty per cent of first-degree relatives of index cases with familial hypercholesterolemia (FH) inherit the disorder. Despite cascade screening being the most cost-effective method for detecting new cases, only a minority of individuals with FH are currently identified. Primary care is a key target area to increase identification of new index cases and initiate cascade screening, thereby finding close relatives of all probands. Increasing public and health professional awareness about FH is essential. In the United Kingdom and in Australia, most of the population are reviewed by a General Practitioner (GP) at least once over a three-year period, offering opportunities to check for FH as part of routine clinical consultations. Such opportunistic approaches can be supplemented by systematically searching electronic health records with information technology tools that identify high risk patients. GPs can help investigate and implement results of this data retrieval. Current evidence suggests that early detection of FH and cascade testing meet most of the criteria for a worthwhile screening program. Among heterozygous patients the long latent period before the expected onset of coronary artery disease provides an opportunity for initiating effective drug and lifestyle changes. The greatest challenge for primary care is to implement an efficacious model of care that incorporates sustainable identification and management pathways