Comparative cost-effectiveness of non-invasive imaging tests in patients presenting with chronic stable chest pain with suspected coronary artery disease: a systematic review.

Coronary artery disease (CAD) remains one of the leading causes of morbidity and mortality globally. The most cost-effective imaging strategy to diagnose CAD in patients with stable chest pain is however uncertain. To review the evidence on comparative cost-effectiveness of different imaging strategies for patients presenting with stable chest pain symptoms suggestive for CAD. Systematic review. Studies performing a formal economic evaluation or decision analysis in the English language published between January 1995 and December 2015 were identified using PubMed, Medline (OvidSP), Embase, Web of Science, Cochrane economic evaluations library, and EconLit. Reviews and meta-analyses were excluded. Two independent reviewers assessed titles and abstracts. Of the 4498 titles identified, 70 met our selection criteria. One reviewer used a modified version of the CHEERS checklist to assess study quality. One reviewer extracted data on study details, which were checked by a second reviewer. There is a major heterogeneity between the available cost-effectiveness studies included in this study. The included studies compared very different testing strategies in very different ways and provided mostly short-term results. Strategies of no-testing and xECG were underrepresented. Nonetheless, the findings from this systematic review suggest that for patients with a low to intermediate prior probability of having obstructive CAD, computed tomography coronary angiography (CTCA) may be cost-effective as an initial diagnostic imaging test in comparison with CAG or other non-invasive diagnostic tests. If functional testing is required, stress echocardiography (SE) or single-photon emission computed tomography (SPECT) are suggested to be cost-effective initial strategies in patients with intermediate prior probability of CAD. Yet, other functional testing strategies such as xECG and positron-emission tomography (PET) scanning have not been studied as intensely. Immediate CAG is suggested to be a cost-effective strategy for patients at a high prior probability of having obstructive CAD whom may benefit from revascularization. The study emphasizes the inextricable link between clinical effectiveness and economic efficiency. Evidence suggests that the optimal diagnostic imaging strategy for individuals suspected of having CAD is CTCA for low and intermediate disease probability, followed by SE or SPECT as necessary, and invasive CAG for high disease probability. Further studies are needed to evaluate the cost-effectiveness of alternative non-invasive tests, including a no-testing strategy.This work forms part of the research areas contributing to the translational research portfolio of the Cardiovascular Biomedical Research Unit at Barts which is supported and funded by the National Institute for Health Research (S.E.P., M.Y.K.)

Prevalence of obstructive coronary artery disease and prognosis in patients with stable symptoms and a zero-coronary calcium score

© The Author 2017. Published by Oxford University Press on behalf of the European Society of Cardiology.Aims: CT calcium scoring (CTCS) and CT cardiac angiography (CTCA) are widely used in patients with stable chest pain to exclude significant coronary artery disease (CAD). We aimed to resolve uncertainty about the prevalence of obstructive coronary artery disease and long-term outcomes in patients with a zero-calcium score (ZCS). Methods and results: Consecutive patients with stable cardiac symptoms referred for CTCS or CTCS and CTCA from chest pain clinics to a tertiary cardiothoracic centre were prospectively enrolled. In those with a ZCS, the prevalence of obstructive CAD on CTCA was determined. A follow-up for all-cause mortality was obtained from the NHS tracer service. A total of 3914 patients underwent CTCS of whom 2730 (69.7%) also had a CTCA. Half of the patients were men (50.3%) with a mean age of 56.9 years. Among patients who had both procedures, a ZCS was present in 52.2%, with a negative predictive value of 99.5% for excluding ≥70% stenosis on CTCA. During a mean follow-up of 5.2 years, the annual event rate was 0.3% for those with ZCS compared with 1.2% for CS ≥1. The presence of non-calcified atheroma on CTCA in patients with ZCS did not affect the prognostic value (P = 0.98). Conclusion: In patients with stable symptoms and a ZCS, obstructive CAD is rare, and prognosis over the long-term is excellent, regardless of whether non-calcified atheroma is identified. A ZCS could reliably be used as a 'gatekeeper' in this patient cohort, obviating the need for further more expensive tests.Peer reviewedFinal Published versio

The AugmenTable: markerless hand manipulation of virtual objects in a tabletop augmented reality environment

The AugmenTable is an augmented reality workstation intended for conceptual design and prototyping. It combines a thin form factor display, inexpensive web cameras, and a PC into a unique apparatus that has advantages similar to a head mounted display. The system operates on well-established computer vision algorithms to detect unmarked fingertips within an augmented reality scene. An application was developed to allow a user to manipulate virtual objects within the scene. This manipulation is possible through the use of three-dimensional widgets and controls that allow the user to control objects with natural fingertip motion. This thesis also documents similar previous work, the methods used to create the AugmenTable, and a number of avenues for advancing the system and the interactions it can offer users.</p