ABSTRACT
The interventional therapy of vascular stent implantation is a popular treatment method for cardiovascular stenosis and blockage. However, traditional stent manufacturing methods such as laser cutting are complex and cannot easily manufacture complex structures such as bifurcated stents, while three-dimensional (3D) printing technology provides a new method for manufacturing stents with complex structure and personalized designs. In this paper, a cardiovascular stent was designed, and printed using selective laser melting technology and 316L stainless steel powder of 0-10 µm size. Electrolytic polishing was performed to improve the surface quality of the printed vascular stent, and the expansion behavior of the polished stent was assessed by balloon inflation. The results showed that the newly designed cardiovascular stent could be manufactured by 3D printing technology. Electrolytic polishing removed the attached powder and reduced the surface roughness Ra from 1.36 µm to 0.82 µm. The axial shortening rate of the polished bracket was 4.23% when the outside diameter was expanded from 2.42 mm to 3.63 mm under the pressure of the balloon, and the radial rebound rate was 2.48% after unloading. The radial force of polished stent was 8.32 N. The 3D printed vascular stent can remove the surface powder through electrolytic polishing to improve the surface quality, and show good dilatation performance and radial support performance, which provides a reference for the practical application of 3D printed vascular stent.
Subject(s)
Humans , Stainless Steel , Powders , Cardiovascular System , Constriction, PathologicABSTRACT
Objective:To analyze the relationship of lipoprotein associated phospholipase A 2 (Lp-PLA2) and severity of coronary atherosclerosis, and evaluate the effects of rosuvastatin at different doses on the concentration of plasma Lp -PLA2.Methods: Totally 152 cases of patients with suspected coronary heart disease were treated with coronary angiography .According to the results of angiogra-phy, the patients were divided into the coronary heart disease group ( n=117 ) and the normal control group ( without coronary heart disease,n=35).Gensini integral scale was performed and referring to the number of diseased coronary arteries , the degree of coronary atherosclerosis was evaluated .The concentration of serum Lp-PLA2 was detected and the relationship of Lp-PLA2 and the severity of coronary plaque was evaluated .Meanwhile , the patients with coronary heart disease were divided into 2 groups and orally treated with rosuvastatin respectively at the routine dose (10 mg· d-1 ) and the loading dose (20 mg· d-1 ).The changes of the plasma concentra-tion of Lp-PLA2 before the treatment, in the 2nd, 4th,8th and 12th week after the medication were measured and the effect of atorvastatin at different doses on the plasma concentration of Lp-PLA2 was summarized .Results: The plasma Lp-PLA level in the control group was (22.22 ±1.75) μmol· ml-1, while that in the coronary heart disease group was (29.03 ±3.99) μmol· ml-1(P0.05).Conclusion:Lp-PLA2 is correlated with the severity of coronary plaque .High dose of rosuvastatin can reduce plasma Lp-PLA2 concentration in the patients .