Theory and practical based approach to chronic total occlusions

Coronary chronic total occlusions (CTOs) represent the most technically challenging lesion subset that interventional cardiologists face. CTOs are identified in up to one third of patients referred for coronary angiography and remain seriously undertreated with percutaneous techniques. The complexity of these procedures and the suboptimal success rates over a long period of time, along with the perception that CTOs are lesions with limited scope for recanalization, account for the underutilization of CTO Percutaneous Coronary Intervention (PCI). During the last years, dedicated groups of experts in Japan, Europe and United States fostered the development and standardization of modern CTO recanalization techniques, achieving success rates far beyond 90 %, while coping with lesions of increasing complexity. Numerous studies support the rationale of CTO revascularization following documentation of viability and ischemia in the territory distal to the CTO. Successful CTO PCI provide better tolerance in case of future acute coronary syndromes and can significantly improve angina and left ventricular function. Randomized trials are on the way to further explore the prognostic benefit of CTO revascularization. The following review reports on the theory and the most recent advances in the field of CTO recanalization, in an attempt to promote a more balanced approach in patients with chronically occluded coronary arteries

Thrombus aspiration in primary angioplasty for ST-segment elevation myocardial infarction

Mechanical reperfusion with primary percutaneous coronary intervention in acute ST-segment-elevation myocardial infarction is superior to fibrinolysis in terms of short-term and long-term outcome, provided that it can be delivered on time and by an experienced team. Balloon angioplasty and stent implantation of an occluded epicardial vessel during ST-segment-elevation myocardial infarction can cause disruption of the frail thrombus containing lesions associated with suboptimal myocardial reperfusion and microcirculatory obstruction. Distal embolization of atherothrombotic material can be prevented by thrombus aspiration during primary angioplasty. Mechanical aspiration via end-hole large-lumen thrombectomy catheters has been shown to improve Thrombolysis in Myocardial Infarction (TIMI) flow and result in a more consistent early resolution of ST-segment elevation in multiple registries. More recently, a more sophisticated quantification of the myocardial damage has been applied using myocardial scintigraphy and magnetic resonance, with no difference between patients treated with thrombectomy and patients treated with conventional therapy. The expectations in terms of lasting mortality benefit raised by the first Dutch single-center randomized trial of thrombectomy versus predilation with plain old balloon angioplasty (Thrombus Aspiration During Percutaneous Coronary Intervention in Acute Myocardial Infarction, TAPAS) were not confirmed by a much larger Swedish trial (Thrombus Aspiration ST-Segment Elevation Myocardial Infarction, TASTE) showing no outcome changes. Although we are waiting for new trials to clarify these controversial results, thrombectomy is still used in selected patients with high thrombus load or with persistent occlusion of the infarct-related artery after wire passage. Here we review the various systems available and discuss their relative merits and the reported results

Modelling of 4H-SiC VJFETS with self-aligned contacts

Summarization: Purely vertical 4H-SiC JFETs have been modeled by using three different approaches: the analytical model, the finite element model and the compact model. The results of the modelling have been compared with experimental results obtained on a series of fabricated self-aligned devices with two different channel lengths (0.3 and 1.1μm) and various channel widths (1.5, 2, 2.5, 3, 4 and 5 μm). For all the considered models I-V and C-V characteristics could be satisfactorily simulated.Παρουσιάστηκε στο: 16th International Conference on Silicon Carbide and Related Material

Global Practice Patterns in the Evaluation of Non-Obstructive Azoospermia: Results of a World-Wide Survey and Expert Recommendations

Purpose: Non-obstructive azoospermia (NOA) represents the persistent absence of sperm in ejaculate without obstruction, stemming from diverse disease processes. This survey explores global practices in NOA diagnosis, comparing them with guidelines and offering expert recommendations. Materials and methods: A 56-item questionnaire survey on NOA diagnosis and management was conducted globally from July to September 2022. This paper focuses on part 1, evaluating NOA diagnosis. Data from 367 participants across 49 countries were analyzed descriptively, with a Delphi process used for expert recommendations. Results: Of 336 eligible responses, most participants were experienced attending physicians (70.93%). To diagnose azoospermia definitively, 81.7% requested two semen samples. Commonly ordered hormone tests included serum follicle-stimulating hormone (FSH) (97.0%), total testosterone (92.9%), and luteinizing hormone (86.9%). Genetic testing was requested by 66.6%, with karyotype analysis (86.2%) and Y chromosome microdeletions (88.3%) prevalent. Diagnostic testicular biopsy, distinguishing obstructive azoospermia (OA) from NOA, was not performed by 45.1%, while 34.6% did it selectively. Differentiation relied on physical examination (76.1%), serum hormone profiles (69.6%), and semen tests (68.1%). Expectations of finding sperm surgically were higher in men with normal FSH, larger testes, and a history of sperm in ejaculate. Conclusions: This expert survey, encompassing 367 participants from 49 countries, unveils congruence with recommended guidelines in NOA diagnosis. However, noteworthy disparities in practices suggest a need for evidence-based, international consensus guidelines to standardize NOA evaluation, addressing existing gaps in professional recommendations