Koshy Santhosh K G, Kleiman Neal S, George Lekha K, Misra Vijay, Hillegass William B, Brott Brigitta C
Department of Medicine, University of Tennessee Health Science Center, 1211 Union Avenue, Suite 340, Memphis, TN 38104, USA.
J Invasive Cardiol. 2008 Oct;20(10):560-2.
Restenosis remains an important issue even after coronary brachytherapy despite its efficacy in the treatment for in-stent restenosis. The acute and chronic changes in vascular wall are unique following brachytherapy. The restenotic tissue post coronary brachytherapy is relatively acellular and appears echolucent in intravascular ultrasound examination. This is dubbed the "black hole" phenomenon. Despite the similarity in the mode of action of brachytherapy and drug eluting stent implantation, the black hole phenomenon seems to be uncommon after drug-eluting stent implantation except in those patients who have had prior brachytherapy, bare-metal placement and after treatment of saphenous venous graft stenosis. It is possible that not all neointima in stents are created equal. We should propose that neointima be considered primary neointima if it forms after bare metal stenting, secondary neointima if it forms after CBT or DES, and perhaps tertiary if after combined CBT and DES. This type of classification may prove useful for research or clinical purposes. Almost certainly black hole phenomenon results from a modified neointima. However, we do not know whether this is the same restenotic tissue that was present before CBT but just depleted of its cellular element secondary to autolysis or a newly formed tertiary neointima? It is also not clear whether the changes in vascular wall and restenosis are similar after CBT or drug-eluting stent placement. However, there are some unique vascular changes that seem to be common after both of these procedures.
尽管冠状动脉近距离放射治疗在治疗支架内再狭窄方面具有疗效，但再狭窄仍然是一个重要问题。近距离放射治疗后血管壁的急性和慢性变化是独特的。冠状动脉近距离放射治疗后的再狭窄组织相对无细胞，在血管内超声检查中呈低回声。这被称为“黑洞”现象。尽管近距离放射治疗和药物洗脱支架植入的作用方式相似，但除了那些曾接受过近距离放射治疗、裸金属支架置入以及大隐静脉移植血管狭窄治疗的患者外，药物洗脱支架植入后黑洞现象似乎并不常见。有可能并非所有支架内的新生内膜都是相同的。我们应该提出，如果新生内膜在裸金属支架置入后形成，则应视为原发性新生内膜；如果在冠状动脉近距离放射治疗（CBT）或药物洗脱支架（DES）后形成，则视为继发性新生内膜；如果在CBT和DES联合治疗后形成，则可能视为三级新生内膜。这种分类方式可能对研究或临床目的有用。几乎可以肯定，黑洞现象是由修饰后的新生内膜导致的。然而，我们不知道这是否是CBT之前就存在的相同再狭窄组织，只是由于自溶而使其细胞成分减少，还是新形成的三级新生内膜？也不清楚CBT或药物洗脱支架置入后血管壁的变化和再狭窄是否相似。然而，在这两种操作后似乎存在一些共同的独特血管变化。
