Objective:To investigate the endothelialization and intermediate and long-term patency rate of prostheses seeded by CD34+ stem cells.Methods:sixteen crossbred dogs were randomized into 2 groups.Prostheses covered with ePTFE or Dacron were implanted into the abdominal aorta artery(AAA) and inferior vena cava(IVC).Twelve dogs were implanted by prostheses seeded by CD34+ stem cells,4 dogs were implanted by autogenous blood only as control.The prostheses were explanted at thirty or sixty or one hundred days.Light and electron microscopy were applied to examine endothelialization of prostheses.CD34 factor stain was used to identify endothelial cells.Results:All venous prostheses implanted by autogenous blood were blocked.Others were patent.Confluent endothelial cells appeared on the neointima of seeded prostheses.There were no endothelial cells in the no-implanted prostheses.Conclusion:Endothelialization and higher patency rate might be achieved in the prostheses covered with ePTFE or Dacron that were implanted by CD34+ stem cells.

Objective To analyze the retrieval rate of inferior vena cava filter(IVCF)and its safety,and to make a histological analysis of the filter attachment substances.Methods The clinical data of 234 patients with IVCF,who were admitted to Affiliated Tenth People's Hospital,Tongji University,to retrieve IVCF between June 2020 and May 2023,were retrospectively analyzed.The retrieval success rate,complications and filter attachment substances were statistically analyzed,and the nature of the attachment substances was examined by using histological staining.Results The retrieval success rate in the 234 patients was 91.03％(213/234).In 17 patients the retrieval of IVCF was abandoned due to the filter capturing the thrombus,and in 4 patients the retrieval of IVCF failed due to tilting of the filter.No complications such as vena cava perforation,symptomatic pulmonary embolism and hemorrhage occurred in all patients during perioperative period.Of the 213 patients whose filter was successfully removed,the filter attachment substances was found in 156 patients.Histological staining of the filter attachment substances demonstrated that the main component of these substances was a mixed thrombus with a small amount of cellulose degeneration.Further analysis revealed that the incidence of filter attachment substances in ≤14-day group was lower than than that in＞14-day group,and the difference between the two groups was statistically significant(x2=6.791,P=0.009);and the incidence of filter attachment substances in the non-anticoagulant group was lower than that in the anticoagulant group,and the difference between the two groups was statistically significant(x2=7.774,P=0.005).Conclusion The retrieval rate of retrievable IVCFs is quite high and the retrieval procedure carries less complications,therefore,it is safe to use retrievable IVCFs in clinical practice.However,the formation of tiny thrombosis within the filter after the placement of filter cannot be ignored,which should be seriously considered in the clinical work.