Research and development of novel embolization materials and study on their feasibility of preventing T2EL after EVAR abdominal aortic aneurysm.

OBJECTIVE

This study aimed to develop a novel vascular embolization material-Thrombin-Coated Controllable Coil (TCC)-and to evaluate its physicochemical properties, biological performance, and feasibility in preventing Type II Endoleak (T2EL) following Endovascular Aneurysm Repair (EVAR) for abdominal aortic aneurysm (AAA).

METHODS

TCC was prepared by coating an interlocking detachable coil (IDC) with a polyvinylpyrrolidone/polycaprolactone (PVP/PCL) blend containing lyophilized thrombin powder (LTP). Its morphology, dissolution, and thrombin-loading capacity were characterized. Coagulation efficiency was tested under static and dynamic conditions. The effects of TCC on vascular endothelial (VECs) and smooth muscle cells (VSMCs) were assessed in vitro, and a Bama minipig AAA model with T2EL was used to evaluate in vivo performance. Transcriptomic analysis was conducted to explore underlying molecular mechanisms.

RESULTS

TCC exhibited a uniform thrombin coating layer, with an average drug loading of 0.0066 ± 0.0003 g, and the water solubility time was 1,080 ± 42.43 s. In the static and dynamic coagulation experiments, compared with the IDC group and the control group, TCC significantly shortened the coagulation time, and its coagulation efficiency was comparable to that of LTP. Extracellularly, TCC promoted apoptosis of VSMCs, inhibited the proliferation and migration of VSMCs, and had a relatively minor effect on VECs. In vivo, TCC effectively prevented T2EL, achieved complete thrombosis within the aneurysm, and no complications occurred. Transcriptomic analysis revealed 161 differentially expressed genes, including downregulation of MMP9, VDR, E2F8, RUNX2, and MKI67, and upregulation of BTG2, IGFBP6, LGR5 and DPT.

CONCLUSION

TCC exhibits excellent biocompatibility, controllability, strong thrombogenic activity and safety. It is a highly promising next-generation embolic material for treating EVAR-related complications.