Experimental study of bioabsorbable iron-based pulmonary artery stent

Objective To monitor the degradation and bio-safety features of the bioabsorbable iron-based stent planted in the pig pulmonary artery. Methods A total of 19 miniature pigs were randomly assigned into 3 groups.Three cases were assigned as the control group; ten cases were assigned as stent implantation group A with one stent implanted in the pig pulmonary artery; the other six cases were assigned as stent implantation group B with two stents implanted in the pig pulmonary artery.Follow-up studies for 24 months were conducted in all cases.Repeated measures ANOVA were used to collect and analyze statistical processing data at multiple time points of the follow-up. Results After surgery, pulmonary artery blood flow velocity and right ventricular pressure were measured by echocardiography and cardiac catheterization.There was no significant difference in pulmonary artery blood flow velocity(Fgroup×time=1.06, P=0.40) and right ventricular pressure (Fgroup×time=0.58, P=0.86) among each group, and no vascular re-narrow circumstance was indicated.Pulmonary artery diameter expansion rate between stent group and control group was statistically different (Fgroup=3.57, P=0.05; Ftime=12.89, P<0.001; Fgroup×time=2.99, P=0.03), suggesting that the stent could maintain a good expansion of the role of vascular in the follow-up period even though in degradation.Difference in the level of serum iron concentrations among the groups was not statistically significant (Fgroup×time=0.94, P=0.52), suggesting that there was no evidence of iron overload.All animals survived to the follow-up endpoint, and no serious side effects caused by stent implantation were found. Conclusions Bioabsorbable iron-based stent planted in the pig pulmonary artery may experience a certain degree of degradation, and it is safe and stabile in animals. Key words: Bioabsorbable stent; Iron; Pulmonary artery; Congenital heart disease; Child