A Novel System for Transcatheter Aortic Valve Implantation: First-in-Man Study.

Transcatheter aortic valve implantation (TAVI) has become a therapeutic treatment for severe symptomatic patients with aortic stenosis. This study aimed to test a novel transcatheter aortic self-expandable bioprosthesis-the ScienCrown system (Lepu Medtech Inc., Beijing, China)-and evaluate the safety of the new device during TAVI. ScienCrown aortic valve implantation was performed on 10 patients. Clinical assessment was performed at baseline, post procedure, and after 1 year. Clinical outcomes and adverse events were assessed according to Valvular Academic Research Consortium-3 criteria. The mean age was 75.30 ± 4.78 years with a mean Society of Thoracic Surgeons score of 4.64 ± 3.23%. Device success was achieved in all patients (80% transfemoral, 20% transapical). After 1 year, there were no deaths, disabling strokes, myocardial infarctions, conversions to surgery, or major procedure-related complications. New pacemaker implantation was required in one patient (10%). ScienCrown implantation resulted in a reduction in mean valve gradient (63.00 ± 18.84 to 9.67 ± 4.97 mm Hg, p <0.001) and an increase in effective orifice area (0.57 ± 0.20 to 2.57 ± 0.59 cm2, p <0.001) at 1 year. Paravalvular leak was absent in 9 patients (90%), and there was a trace in one patient (10%). All patients were in New York Heart Association class I to II at a mean follow-up of 1 year. The experience showed that ScienCrown transcatheter aortic valve system was safely and successfully implanted for treatment of severe symptomatic aortic stenosis. The newer-generation device affords a stable implantation while providing optimal hemodynamic performance.

Influence of biocompatible metal ions (Ag, Fe, Y) on the surface chemistry, corrosion behavior and cytocompatibility of Mg-1Ca alloy treated with MEVVA.

Mg-1Ca samples were implanted with biocompatible alloy ions Ag, Fe and Y respectively with a dose of 2×10(17)ionscm(-2) by metal vapor vacuum arc technique (MEVVA). The surface morphologies and surface chemistry were investigated by SEM, AES and XPS. Surface changes were observed after all three kinds of elemental ion implantation. The results revealed that the modified layer was composed of two sublayers, including an outer oxidized layer with mixture of oxides and an inner implanted layer, after Ag and Fe ion implantation. Y ion implantation induced an Mg/Ca-deficient outer oxidized layer and the distribution of Y along with depth was more homogeneous. Both electrochemical test and immersion test revealed accelerated corrosion rate of Ag-implanted Mg-1Ca and Fe-implanted Mg-1Ca, whereas Y ion implantation showed a short period of protection since enhanced corrosion resistance was obtained by electrochemical test, but accelerated corrosion rate was found by long period immersion test. Indirect cytotoxicity assay indicated good cytocompatibility of Y-implanted Mg-1Ca. Moreover, the corresponding corrosion mechanisms involving implanting ions into magnesium alloys were proposed, which might provide guidance for further application of plasma ion implantation to biodegradable Mg alloys.

Ti-Ge binary alloy system developed as potential dental materials.

As-cast Ti-xGe (x = 2, 5, 10, 20 wt %) binary alloys were produced in this work, and various experiments were carried out to investigate the microstructure, mechanical properties, in vitro electrochemical and immersion corrosion behaviors as well as cytotoxicity with as-cast pure Ti as control, aiming to study the feasibility of Ti-xGe alloy system as potential dental materials. The microstructure of Ti-xGe alloys changes from single α-Ti phase to α-Ti + Ti(5)Ge(3) precipitation phase with the increase of Ge content. Mechanical tests show that Ti-5Ge alloy has the best comprehensive mechanical properties. The corrosion behavior of Ti-xGe alloys in artificial saliva with different NaF and lactic acid addition at 37°C indicates that Ti-2Ge and Ti-5Ge alloys show better corrosion resistance to fluorine-containing solution. The cytotoxicity test indicates that Ti-xGe alloy extracts show no obvious reduction of cell viability to L-929 fibroblasts and MG-63 osteosarcoma cells, similar to pure Ti which is generally acknowledged to be biocompatible. Considering all these results, Ti-2Ge and Ti-5Ge alloys possess the optimal comprehensive performance and might be used as potential dental materials.