肝素缓释可降解支架在心肌血运重建中的应用研究

Experimental Study of Heparin-Slow-Release Stent in Myocardial Revascularization after Acute Myocardial Infarction

目的:探讨肝素缓释支架在急性心肌梗死后心肌血运重建中的作用。方法:通过结扎前降支冠状动脉制作猪急性心肌梗死模型,然后随机分为3组,A组(6只)为对照组,B组(6只)为心肌打孔组,C组(6只)为心肌打孔+支架植入组。在B组和C组中,于心肌梗死区采用自制高速钻孔器由心外膜打2个直径为3.5mm透壁孔道,C组每个孔道内植入1枚肝素缓释支架。分别于治疗前和治疗后6周观察组织学改变、新生血管密度、心肌灌注及心功能变化。结果:治疗后6周,B组孔道完全闭塞,C组孔道仍然开放,内壁被一层内皮细胞覆盖。C组中新生血管密度较A组和B组明显增加(均P<0.001);治疗前后C组灌注质量缺损百分率的差值(△MDP)较A组和B组明显改善(均P<0.001);C组存活心肌面积较A组和B组明显增加(均P<0.01);C组左室射血分数为较A组和B组明显提高(均P<0.05)。结论:肝素缓释支架可以维持穿心肌孔道开放,促进心肌梗死后血管再生,增加心肌灌注,提高心肌存活,改善心功能,可能成为心肌梗死后再血管化的有效方法。

Objective： To investigate the effect of heparin-slow-release stent implanted into transmural channels on myocardial revascularization after acute myocardial infarction. Methods： The animal models were established by ligation of the mid third of left anterior descending （LAD） in miniswine. Miniswines were divided into control group （A group, n = 6）, transmyocardial drilling revascularization （TMDR） group （B group, n = 6） and TMDR＋stent implantation group （C group, n = 6）. In B and C groups, two transmural channels with 3.5 mm in diameter were established by using a self-made drilling device, followed by implantation of two stents into the channels in C group. The vascular density, myocardial perfusion, histological and morpho-logical analyses, and left ventricular （LV） function were evaluated at pre-treatment and 6 weeks post-treatment. Results： The vascular density was significantly increased after 6 weeks treatment in C group compared with that in A group and B group （P 0.001）. Changes of mass defect percent （△MDP） were significantly decreased in B group compared with that of A group and B group. There were more viable cardiaomyocytes in C group than that in A group（P 0.001） and B group（P = 0.003）. LV ejection fraction （EF） was significantly increased in C group than that of A group（P = 0.037） and B group（P = 0.019）. There were no significant differences in these parameters between A group and B group. Conclusion： The heparin-slow-release stent implanted into transmural channel could keep the channel open and promote luminal endothelialization by continuous anticoagulation, which promoted angiogenesis, increased myocardial perfusion, enhanced myocardial viability, improved LV function. The heparin-slow-release stent may be a new method for myocardial revascularization of acute myocardial infarction.