PubMed · 6571293
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C R Sadler. 1984. Orthopedic computing: bone and joint computer connection.. https://pubmed.ncbi.nlm.nih.gov/6571293/
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BACKGROUND: The influence of prior coronary artery bypass surgery (CABG) versus medical therapy for reducing the risk of postoperative cardiac complications after noncardiac surgery continues to be debated. To further clarify this controversy we studied 24,959 participants in the Coronary Artery Surgery Study (CASS) database with suspected coronary disease by identifying those who required noncardiac surgery during more than 10 years of follow-up. METHODS AND RESULTS: CASS registry enrollees were either treated with CABG or medical therapy after initial entry. During follow-up, patients who required noncardiac operations were evaluated for hospital death or out-of-hospital death within 30 days of noncardiac surgery and nonfatal postoperative myocardial infarction (MI). At a mean follow-up of 4.1 years, 3368 patients underwent noncardiac surgery, with abdominal (36%), urologic (21%), orthopedic (15%), and vascular being most common. Abdominal, vascular, thoracic, and head and neck surgery each had a combined MI/death rate among patients with nonrevascularized coronary disease >4%. Among 1961 patients undergoing higher-risk surgery, prior CABG was associated with fewer postoperative deaths (1.7% versus 3.3%, P=.03) and MIs (0.8% versus 2.7%, P=.002) compared with medically managed coronary disease. Contrariwise, 1297 patients undergoing urologic, orthopedic, breast, and skin operations had mortality of <1% regardless of prior coronary treatment. Prior CABG was most protective in patients with advanced angina and/or multivessel coronary artery disease. CONCLUSIONS: In patients with known coronary artery disease, noncardiac surgeries involving the thorax, abdomen, vasculature, and head and neck are associated with the highest cardiac risk, which is reduced among patients with prior CABG.
Many natural objects, including most objects studied in pathology, have complex structural characteristics and the complexity of their structures, for example the degree of branching of vessels or the irregularity of a tumour boundary, remains at a constant level over a wide range of magnifications. These structures also have patterns that repeat themselves at different magnifications, a property known as scaling self-similarity. This has important implications for measurement of parameters such as length and area, since Euclidean measurements of these may be invalid. The fractal system of geometry overcomes the limitations of the Euclidean geometry for such objects and measurement of the fractal dimension gives an index of their space-filling properties. The fractal dimension may be measured using image analysis systems and the box-counting, divider (perimeter-stepping) and pixel dilation methods have all been described in the published literature. Fractal analysis has found applications in the detection of coding of coding regions in DNA and measurement of the space-filling properties of tumours, blood vessels and neurones. Fractal concepts have also been usefully incorporated into models of biological processes, including epithelial cell growth, blood vessel growth, periodontal disease and viral infections.
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