Non-invasive Ischaemia Testing in Patients With Prior Coronary Artery Bypass Graft Surgery: Technical Challenges, Limitations, and Future Directions

Coronary artery bypass graft (CABG) surgery effectively relieves symptoms and improves outcomes. However, patients undergoing CABG surgery typically have advanced coronary atherosclerotic disease and remain at high risk for symptom recurrence and adverse events. Functional non-invasive testing for ischaemia is commonly used as a gatekeeper for invasive coronary and graft angiography, and for guiding subsequent revascularisation decisions. However, performing and interpreting non-invasive ischaemia testing in patients post CABG is challenging, irrespective of the imaging modality used. Multiple factors including advanced multi-vessel native vessel disease, variability in coronary hemodynamics post-surgery, differences in graft lengths and vasomotor properties, and complex myocardial scar morphology are only some of the pathophysiological mechanisms that complicate ischaemia evaluation in this patient population. Systematic assessment of the impact of these challenges in relation to each imaging modality may help optimize diagnostic test selection by incorporating clinical information and individual patient characteristics. At the same time, recent technological advances in cardiac imaging including improvements in image quality, wider availability of quantitative techniques for measuring myocardial blood flow and the introduction of artificial intelligence-based approaches for image analysis offer the opportunity to re-evaluate the value of ischaemia testing, providing new insights into the pathophysiological processes that determine outcomes in this patient population

Program design, abstract machines and the design engineer

Structured programming is a design methodology for producing computer programs. A technique is described for designing programs by this methodology, together with the use of abstract machines, so that the logic designer producing programs for microprocessors can do so in a more natural way

Processor management in a multiprocessor system

In a single-processor system, much investigation has been carried out into the way in which memory should be managed. In a multiprocessor system, the management of processors is equally important, and many of the results of memory management investigations are applicable to processor management also. The letter explains the similarities and their consequences on processor-management policies in a multiprocessor system

Simulating hardware structures in occam

Occam is a low-level programming language designed specifically to program an array of transputers, although it may be implemented on a single transputer or other processor using a suitable run-time support system. The paper describes the use of occam to model combinatorial and sequential logic systems. The suitability of occam for such modelling is discussed

Assessing word-processing skills by event stream analysis

This paper derives the algorithms required to process the stream of textual events collected from a candidate's interaction with a word processor to produce an assessment of their word-processing skills. The information that can be extracted from the textual event stream is compared to that which can be deduced from a comparison of the candidate's submitted answer with the model answer(s) generated by the examiner. For many examinations, document comparison is simpler and more efficient than event stream analysis but it is not always possible to fully analyse errors from document comparison; hence a mixture of document comparison and event stream analysis is desirable for computer-based word-processing assessment