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Scheduling is a fundamental optimisation problem that has a wide range of practical applications. Mathematical formulations of scheduling problems allow for development of efficient solvers. Yet, the same mathematical intricacies often make solvers black-boxes: their outcomes are hardly explainable and interactive even to experts, let alone lay users. Still, in real-world applications as well as research environments, lay users and experts likewise require a means to understand why a schedule is reasonable and what would happen with different schedules. Building upon a recently proposed approach to argumentation-supported explainable scheduling, we present a tool, Schedule Explainer, that provides interactive explanations in makespan scheduling easily and with clarity.

To visualize intracoronary lesions in patients with different clinical expressions of coronary disease, we performed coronary angioscopy during coronary-artery bypass surgery in 10 patients with unstable angina and 10 patients with stable coronary disease. We examined a total of 32 vessels, using flexible fiberoptic angioscopes. Twenty-two vessels had no acute intimal lesion; three had complex plaques, six had thrombi, and one had both. Coronary angiography correctly identified the absence of complex plaque and thrombus in 22 vessels, but it detected only one of four complex plaques and one of seven thrombi. On angioscopy, none of the 17 arteries in the patients with stable coronary disease had either a complex plaque or thrombus. In the "offending" arteries of the patients with unstable angina, all three patients with accelerated angina had complex plaques and all seven with angina at rest had thrombi. We conclude that angioscopy frequently reveals complex plaques or thrombi not detected by coronary angiography. Our observations suggest that anginal syndromes that are refractory to medical treatment can be caused by unstable pathologic processes in the intima. Ulceration of plaques may increase the frequency and severity of effort angina, and the subsequent development of partially occlusive thrombi may cause unstable rest angina.

In this study, the development of intraoperative angioscopy, the value of the information obtained, and the problems encountered with the procedure are reported. Eight angioscopes, 1.5 to 2.8 mm in diameter, with a line resolution of greater than 0.4 mm at 5 mm, were used. One-hundred ten angioscopic investigations were performed in 46 patients; 24 at peripheral bypass surgery and 22 at coronary artery bypass surgery. These included 68 arteries, 28 new anastomoses, six old grafts, five laser angioplasties, and three in situ vein grafts. The most important finding was that angioscopic data provide information not available from probes or angiography. Angioscopic findings were responsible for a change in surgical procedures in 12 patients (26%) including three anastomotic revisions, three alterations in graft site placement, and two repeat thrombectomies. The most significant technical problems were lack of steerability and insufficient irrigation, which resulted in poor angiographic images. Further technical development is necessary before routine intraoperative angioscopy is practical. Nevertheless, if these problems are resolved, angioscopy will provide unique, high-resolution information which can directly alter surgical therapy.

Mechanical devices which maintain viability during periods of reduced or absent mechanical cardiac function have permitted the utilization of a variety of surgical techniques for the treatment of acquired and congenital cardiac disease. In addition, many advances in cardiac pharmacology have improved the treatment of abnormal mechanical and electrical cardiac function. Despite a variety of therapeutic approaches, survival rate of hospital patients in cardiogenic shock remains between 10% to 20%.1Malach and Rosenberg2reviewed 264 consecutive cases of acute myocardial infarction at this institution and found the frequency of cardiogenic shock to be 9.4%. Those patients in shock were treated with several pharmacologic and volume replacement regimens with no survivors. More recently, Eichna3reported on the treatment of 26 cardiogenic shock cases at this institution using intravenously administered isoproterenol hydrochloride as the major pharmacologic agent. The death rate was 72%. Drugs remain the most frequent means of