Drug-Eluting Stents ; Stents/adverse effects* ; Treatment Outcome

Drug-Eluting Stents ; adverse effects ; Humans ; Male ; Middle Aged ; Thrombosis ; etiology

Adult ; Coronary Aneurysm ; etiology ; Drug-Eluting Stents ; adverse effects ; Humans ; Male ; Paclitaxel ; therapeutic use

Drug-Eluting Stents ; adverse effects ; Humans ; Male ; Middle Aged ; Myocardial Infarction ; diagnosis ; etiology ; Thrombosis ; etiology ; physiopathology

Coronary Restenosis ; therapy ; Drug-Eluting Stents ; adverse effects ; Humans ; Treatment Outcome

BACKGROUNDDrug-eluting stents represent a major advance in interventional cardiology. However, the current drug-eluting stents have significant limitations. One of the major problems is very late stent thrombosis, which is likely caused by inflammation and a hypersensitivity reaction related to a polymer on the stent. A polymer-free sirolimus-eluting stent with a unique nano-porous surface has been developed. This study aimed to evaluate this novel polymer-free sirolimus-eluting stent for its efficacy and safety in a pig model.

METHODSStents were directly coated with sirolimus (a drug concentration of 2.2 µg/mm(2) on the stent surface). The polymer-free sirolimus-eluting stents (PFSES) were compared to standard polymer-coated sirolimus-eluting stents (PCSES) and bare-metal stents (BMS) in 18 pigs.

RESULTSAt one month the degree of neointimal hyperplasia was similar between the two sirolimus-eluting stent groups and was significantly less compared to BMS ((1.93 ± 0.51) mm(2), (1.57 ± 0.69) mm(2) vs. (4.45 ± 1.05) mm(2), P < 0.05) At three months, PFSES maintained the low level of neointima ((2.41 ± 0.99) mm(2) vs. (4.32 ± 1.16) mm(2), P < 0.05), whereas PCSES had developed significant neointimal proliferation similar to BMS. The inflammation level was significantly higher in PCSES when compared with BMS three months post-implantation (2.50 ± 0.55 vs. 0.83 ± 0.75, P < 0.05) whereas PFSES showed a low level of inflammation comparable to PCSES (1.33 ± 0.52 vs. 2.50 ± 0.55, P < 0.05).

CONCLUSIONThe PFSES is effective and safe, and appears to be superior to standard PCSEs.

Animals ; Drug-Eluting Stents ; adverse effects ; Neointima ; prevention & control ; Polymers ; chemistry ; Sirolimus ; therapeutic use ; Swine

Drug-Eluting Stents ; adverse effects ; Humans ; Male ; Middle Aged ; Prosthesis Failure ; Thrombosis ; etiology

Angioplasty, Balloon, Coronary ; adverse effects ; methods ; Drug-Eluting Stents ; Humans ; Paclitaxel ; therapeutic use

Drug-Eluting Stents ; adverse effects ; Humans ; Middle Aged ; Myocardial Infarction ; etiology ; Sirolimus ; administration & dosage ; Thrombosis ; etiology

New biodegradable intravascular stent can reduce risk of foreign bodies retained, thus, it is widely concerned and some of the products have been introduced into the clinic. However, the characteristic of biodegradable may lead to more safety concerns associated with thrombosis. To ensure the safety, the thrombus formation experiment needs to be carefully designed and evaluated based on GB/T 16886.4 standard, but current standard do not provide explicit testing and evaluating methods. Establishing animal model with experimental pigs, the study compares biodegradable coronary stents and metal stents by simulating clinical implantation on the thrombus formation in the implanting process, and after the short-term and long-term implantation. The evaluation methods include gross observation, digital subtraction angiography intraoperative analysis, optical coherence tomography analysis, scanning electron microscopy and so on. The results show that combining these methods could comprehensively evaluate the whole process of the thrombus formation from the beginning of implantation to the end of preclinical animal experiments, so that, it may better predict the clinical thrombosis risk, and the selection of the control was very important. The study tries to use the comparison examples of thrombosis on the new medical instrument to provide the clue for thrombosis evaluation on similar instruments and show the methodology on the preclinical evaluation.
Absorbable Implants ; adverse effects ; Animals ; Drug-Eluting Stents ; adverse effects ; Polymers ; Swine ; Thrombosis ; etiology ; Tomography, Optical Coherence ; Treatment Outcome