Jabara Refat, Chronos Nicolas, Robinson Keith
Saint Joseph's Translational Research Institute, Saint Joseph's Hospital of Atlanta, Atlanta, Georgia 30342, USA.
Catheter Cardiovasc Interv. 2008 Aug 1;72(2):186-94. doi: 10.1002/ccd.21607.
Permanent polymers used in current drug-eluting stents (DES) can trigger chronic inflammation and hypersensitivity reactions, which may contribute to the increased risk of late thrombosis and rebound restenosis. Therefore, optimal polymer selection and the use of completely absorbable but biocompatible polymers are expected to minimize these risks.
We sought to evaluate a novel, potentially innately anti-inflammatory, bioabsorbable salicylate-based polymer as a DES coating, in a clinically relevant animal model.
Four types of stents were implanted in pig coronary arteries using QCA to optimize stent apposition: bare metal stents (BMS); salicylic acid/adipic acid bioabsorbable polymer-only coated metal stents (SA/AA); biostable polymeric sirolimus-eluting stents (Cypher); and metal stents coated with salicylic acid/adipic acid bioabsorbable polymer containing sirolimus (SA/AA + S). The dose density of sirolimus was 8.3 microg/mm of stent length (similar to Cypher) with in vitro studies demonstrating elution over 30 days and complete polymer degradation in 37 days. Animals underwent angiographic restudy and were terminated at 1 month for complete histopathologic and histomorphometric analyses.
Both SA/AA + S and Cypher stents had significantly lower angiographic % stenosis when compared with BMS and SA/AA polymer-only groups (6 +/- 4% and 5 +/- 4% vs. 15 +/- 7% and 16 +/- 5%, respectively, P < 0.001). Intimal thickness was lower for SA/AA + S and Cypher than for BMS (0.14 +/- 0.06 and 0.13 +/- 0.04 mm vs. 0.23 +/- 0.05 mm, respectively, P < 0.001). Histologic % area stenosis was also lower for SA/AA + S and Cypher when compared with BMS (22 +/- 7% and 23 +/- 6% vs. 33 +/- 5%, respectively, P < 0.001). There was a strong trend toward reduced inflammatory response in the SA/AA and SA/AA + S when compared with BMS and Cypher groups (P = 0.072).
This study shows favorable vascular compatibility and efficacy for a novel bioabsorbable salicylate-based polymer as a DES coating, and supports further research and development of this unique class of polymer materials for applications in cardiovascular devices.
当前药物洗脱支架（DES）中使用的永久性聚合物可引发慢性炎症和超敏反应，这可能会增加晚期血栓形成和再狭窄反弹的风险。因此，选择最佳聚合物并使用完全可吸收但具有生物相容性的聚合物有望将这些风险降至最低。
我们试图在临床相关动物模型中评估一种新型的、可能具有天然抗炎性的、可生物吸收的基于水杨酸盐的聚合物作为DES涂层的效果。
使用定量冠状动脉造影（QCA）优化支架贴壁，将四种类型的支架植入猪冠状动脉：裸金属支架（BMS）；仅涂有水杨酸/己二酸生物可吸收聚合物的金属支架（SA/AA）；生物稳定的聚合物西罗莫司洗脱支架（Cypher）；以及涂有含西罗莫司的水杨酸/己二酸生物可吸收聚合物的金属支架（SA/AA + S）。西罗莫司的剂量密度为每毫米支架长度8.3微克（与Cypher相似），体外研究表明其洗脱时间超过30天，聚合物在37天内完全降解。动物接受血管造影复查，并在1个月时处死以进行完整的组织病理学和组织形态计量学分析。
与BMS组和仅SA/AA聚合物组相比，SA/AA + S支架和Cypher支架的血管造影狭窄百分比均显著降低（分别为6±4%和5±4%，而BMS组和仅SA/AA聚合物组分别为15±7%和16±5%，P<0.001）。SA/AA + S支架和Cypher支架的内膜厚度低于BMS组（分别为0.14±0.06毫米和0.13±0.04毫米，而BMS组为0.23±0.05毫米，P<0.001）。与BMS组相比，SA/AA + S支架和Cypher支架组织学上的狭窄面积百分比也较低（分别为22±7%和23±6%，而BMS组为33±5%，P<0.001）。与BMS组和Cypher组相比，SA/AA组和SA/AA + S组的炎症反应有明显降低的趋势（P = 0.072）。
本研究表明，一种新型的可生物吸收的基于水杨酸盐的聚合物作为DES涂层具有良好的血管相容性和疗效，并支持进一步研发这类独特的聚合物材料用于心血管装置。
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