Objective To analyze and compare pore characteristics and mechanical properties of models with solid and sheet triply periodic minimal surface (TPMS) structures, and build a porous structure with high specific surface area, low stiffness and high strength. Methods The solid TPMS and sheet TPMS models of D, G, and P units with the same porosity were established, and pore characteristics of the model such as pore diameter, rod diameter and specific surface area were compared; mechanical properties of the model were analyzed by finite element method. The porous titanium samples were made by additive manufacturing technology, pore characteristics of porous titanium were observed by microscope and scanning electron microscope, and mechanical properties of porous titanium were detected by compression test. Results The specific surface area of the sheet structure with the same unit was significantly higher than that of the solid structure; mechanical properties of the sheet structure with the same were significantly better than those of the solid structure. Among them, the D unit sheet TPMS model had the most significant advantages, with the specific surface area of 13.00 mm-1, and the elastic modulus, yield strength and compressive strength of the sheet porous titanium sample were (5.65±0.08) GPa, (181.03±1.30) MPa and (239.83±0.45) MPa, respectively, which were 43.87%, 55.08% and 67.21% higher than those of the solid porous titanium sample. Conclusions While retaining low rigidity of the porous structure, the sheet TPMS model of the same unit has a larger specific surface area, which is beneficial for cell adhesion and growth, and its low stiffness and high strength mechanical properties can effectively reduce stress shielding and provide sufficient mechanical support. It is an ideal pore structure model for bone defect repair substitutes.

BACKGROUND: The HELIOS stent is a sirolimus-eluting stent with a biodegradable polymer and titanium oxide film as the tie-layer. The study aimed to evaluate the safety and efficacy of HELIOS stent in a real-world setting. METHODS: The HELIOS registry is a prospective, multicenter, cohort study conducted at 38 centers across China between November 2018 and December 2019. A total of 3060 consecutive patients were enrolled after application of minimal inclusion and exclusion criteria. The primary endpoint was target lesion failure (TLF), defined as a composite of cardiac death, non-fatal target vessel myocardial infarction (MI), and clinically indicated target lesion revascularization (TLR) at 1-year follow-up. Kaplan-Meier methods were used to estimate the cumulative incidence of clinical events and construct survival curves. RESULTS: A total of 2998 (98.0%) patients completed the 1-year follow-up. The 1-year incidence of TLF was 3.10% (94/2998, 95% closed interval: 2.54-3.78%). The rates of cardiac death, non-fatal target vessel MI and clinically indicated TLR were 2.33% (70/2998), 0.20% (6/2998), and 0.70% (21/2998), respectively. The rate of stent thrombosis was 0.33% (10/2998). Age ≥60 years, diabetes mellitus, family history of coronary artery disease, acute myocardial infarction at admission, and device success were independent predictors of TLF at 1 year. CONCLUSION: The 1-year incidence rates of TLF and stent thrombosis were 3.10% and 0.33%, respectively, in patients treated with HELIOS stents. Our results provide clinical evidence for interventional cardiologists and policymakers to evaluate HELIOS stent. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov, NCT03916432.
Humans ; Middle Aged ; Sirolimus/therapeutic use* ; Drug-Eluting Stents/adverse effects* ; Prospective Studies ; Cohort Studies ; Treatment Outcome ; Risk Factors ; Time Factors ; Percutaneous Coronary Intervention/adverse effects* ; Cardiovascular Agents/therapeutic use* ; Coronary Artery Disease/therapy* ; Myocardial Infarction/etiology* ; Thrombosis/complications* ; Polymers ; Registries