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A promising approach for producing parts with outstanding properties in directed energy deposition (DED-LB/M) provides the application of tailored powder mixtures processed by applying in situ alloying strategies. In this work, DED-LB/M was used to manufacture multilayer specimens from AISI H11 steel powders enriched with carbon nanoparticles (C-np) in concentrations of 0.1 wt.-% and 0.2 wt.-%. The scientific aim was to investigate the impact of C-np on the microstructural (particularly retained austenite content (RA-c) and grain size) and mechanical properties (specifically hardness and compression yield strength) of the manufactured specimens. It was shown that the addition of C-np to the H11 powder leads to a stronger distortion of martensite as well as significantly enhancing the RA-c. Furthermore, the C-np seem to favor the formation of finer martensite, as can be verified with XRD and EBSD. Under as-built conditions, the mean hardness increases from 653 ± 10 HV1 for the H11 sample to 770 ± 14 HV1 for the sample reinforced with 0.2 wt.-% C-np. At the same time, Y0.2% rises up from 1839 ± 61 MPa to 2134 ± 68 MPa. The hardness- and strength-increasing effect of the added C-np is retained even after heat treatment, similarly to the industrial standard.

In this study, the DED-LB/M process of AISI H11 tool steel powder blends modified by adding WC nanoparticles (WC-np) in concentrations of 1, 2.5 and 5 wt.-% was the object of scientific investigations. For this, 30-layer cuboid specimens were manufactured. The overall scientific aim was to examine how the WC-np interact with the steel melt and in the end, influence the processability, microstructure and mechanical properties of produced specimens. The examinations were carried out on both as-built and thermally post-processed specimens. An advanced microstructural analysis (SEM, EDS, EBSD and XRD) revealed that due to the high solubility of WC-np in the molten steel, most of the WC-np appear to have dissolved during the ongoing laser process. Furthermore, the WC-np favor a stronger distortion and finer grain size of martensite in the manufactured specimens. An increase in hardness from about 650 HV1 for the H11 specimen to 780 HV1 for the one manufactured using the powder blend containing 5 wt.-% of WC-np was observed in as-built conditions. In the same way, the compression yield strength enhanced from 1839 MPA to 2188 MPA. The hardness and strength increasing effect of WC-np remained unchanged even after heat treatments similar to those used in industry.

Introduction: The self-expanding, resheathable, repositionable transcatheter aortic heart valve Portico is being used successfully for transcatheter aortic valve implantation procedures (TAVI) in patients with severe aortic stenosis. The aim of this study was to evaluate outcomes at 2 years after TAVI with the Portico valve. Methods: Multicenter registry of clinical, echocardiographic and survival data from consecutive patients treated with the Portico TAVI system (Abbott, Chicago, IL, USA) in three cath labs in Northern Greece and Epirus during 2017–2020. The primary end point was all-cause mortality at 24 months. Secondary end points included procedural outcomes (efficacy and safety) and echocardiographic measurements. Results: A total of 90 patients (81 ± 6 years, 50% females, mean age 81 ± 6 years) were included in the registry. The indication for implantation was severe, symptomatic aortic stenosis (NYHA III, IV) in eighty-two (91.1%) and degeneration of a prosthetic aortic valve in eight (8.9%) patients. All patients were categorized as high surgical risk (mean Logistic Euroscore 25.9 ± 10, Euroscore II 7.7 ± 4.4 and STS score 10.8 ± 8.9). The procedure was performed transfemorally in all patients, under general anesthesia in 95.6%, under TOE guidance in 21.1%, with native valve predilatation in 46.7%, and the “resheath” option was used in 31.1% of the cases. The implantation was successful in 97.8% and there was a need for a second valve in 2.2% of the cases. Complications included permanent pacemaker implantation (16.7%), access cite complications (15.6%), arrythmias (23.3%), paravalvular leak (moderate 7.8%, severe 1.1%), acute kidney injury (7.8%), no strokes and one death during the procedure. Aortic valve peak velocity, peak and mean pressure gradients, were significantly reduced after the procedure. All-cause mortality at 1, 12 and 24 months was 4.4%, 6.7% and 7.8%, respectively. Conclusions: TAVI with the Portico system comprises an effective and safe solution for the management of severe, symptomatic aortic stenosis in high-risk surgical patients.

Anatomical variations of the cystic artery are frequently documented, but variations of the artery to the cystic duct are extremely uncommon. We report a rare duplication of the artery to the cystic duct, revealed during laparoscopic cholecystectomy on an 18-year-old Caucasian female treated for gallstone disease. Both arterial branches were meticulously and carefully retracted and cauterized to avoid bleeding and subsequent postoperative complications. To our knowledge, this is the first reported case of an artery to the cystic duct duplication. The presence of congenital variations of the artery to the cystic duct encumbers surgical maneuvers and increases the potentiality of intraoperative injury and hemorrhage.

Background/Aims: Several studies have implicated atrial fibrillation (AF) as a contributing factor in chronic kidney disease (CKD) and cardiovascular events. The prevalence of coronary artery disease (CAD) in patients with AF varies substantially from 17% to 46.5%. There are only few studies concerning renal function in population with AF undergoing coronary angiography. The aim of the present study was to assess which type of AF is dominant in CKD population scheduled for coronary angiography and if it can influence patients’ outcome, the association between renal impairment and the type of coronary procedures in AF patients and the influence of renal function on in-hospital mortality. Methods: We retrospectively studied 867 patients with AF hospitalized due to coronary angiography in two year time. The cut off value of CKD was eGFR ≤ 60 ml/min./1.73m2 evaluated by CKD-EPI formula. Results: A total of 867 patients with AF (44% women; mean age 72±10 years) were included in the analysis. The mean eGFR was 44±11ml/min./1.73m2 in patients with CKD and 89±18 ml/min./1.73m2 in patients with preserved renal function. Patients with CKD and AF were older (p< 0.001), had more often diabetes (p=0.009), heart failure (p< 0.001) and anaemia (p< 0.001). Patients with CKD and AF had more often permanent type of AF (p< 0.001). In CKD patients CHA2DS2VASc score was 4.3±1.5 and HAS-BLED score was 2.0±1.2 and it was significantly higher as compared to population with preserved renal function (p< 0.001, p=0.02, respectively). The use of oral anticoagulation was less frequent in CKD group (p< 0.001) although these patients had higher CHA2DS2VASc score. Patients with AF and CKD were more often admitted due to myocardial infarction (STEMI or NSTEMI) (p=0.02, p< 0.001, respectively) and more often underwent percutaneous coronary intervention (PCI) (p=0.01). Among coronary arteries the percutaneous coronary intervention (PCI) of left main artery was done more frequently in CKD patients (p=0.01). Among CKD population in-hospital mortality was significantly higher in patients with eGFR < 30 ml/min (p< 0.001). Conclusion: Patients with CKD had more often permanent type of AF. Percutaneous interventions of the left main coronary artery, the only elective procedures influencing patients’ prognosis, were done more frequently in CKD patients with AF. In-hospital mortality was significantly higher in patients with severe renal impairment. Despite the higher risk of ischaemic stroke in CKD group the use of oral anticoagulation therapy was significantly less frequent and the patients were deprived of the confirmed benefits of such treatment.

Objective: We examined trans-radial approach (TRA) use in coronary angiographies (CAs) as well as in percutaneous coronary interventions (PCIs) in specific regions of Greece, its distribution in public and private catheterization laboratories (CLs) and its preference by operators. Reliable data regarding the use of TRA are not available in Greece. Methods: The study was performed in northern and central Greece, which constitutes 35.32% of the national population. This study focused on the years 2004, 2009 and 2013. Results: There are 12 CLs. CAs performed using TRA were 0.43% in 2004, 12.28% in 2009 and 39.81% in 2013, whereas PCIs performed using TRA were 0.38%, 9.20% and 39.48%, respectively. Operators familiar with TRA, but who performed TRA electively, were 13.33% in 2004, 60.38% in 2009 and 42.37% in 2013. However, operators performing TRA routinely were 2.2%, 5.66%, and 49.15%, respectively. In 2013, there was a 3.76% decrease in CAs and 4.51% decrease in PCIs compared to 2009; in private CLs, there was a 29.63% decrease in CAs and 34.72% decrease in PCIs performed, which was contradictory to the 27.27% increase observed in CAs and 29.83% increase in PCIs in public CLs. Conclusions: This is the first study to reveal the volumes and trends in interventions performed via TRA across central and northern Greece. TRA has gained a reputation among operators in both public and private CLs. Due to the financial crisis in Greece, catheterizations have been diminished, whereas private CLs have lost a great amount of their turnover.

Abstract Infantile soft tissue tumors of the head are very rare and the majority of them are myofibromas. The authors present the case of a 1-day-old boy with a scalp tumor with several distinct histopathological features including myofibroma, hemangiopericytoma, and fibrosarcoma consistent with the diagnosis of composite infantile myofibromatosis. Genetic testing was negative for trisomy 17, translocation (12; 15), FUS, and ETV6 translocations. Despite the ominous histopathological features, the clinical course was benign. The authors review here available literature concerning current concepts of making the diagnosis of composite infantile myofibromatosis and discuss treatment options.