摘要

目的：为了确定在冠状动脉重建术中使用过大的球囊这种过于积极的措施是不是有反作用，我们研究了首次支架置入术后增加的球囊比动脉比值(B:A)对新生内膜增生的影响，模型是没有动脉粥样硬化的猪的过度牵张的冠状动脉。

方法：33只约克郡猪的66条血管被随机分配到介于1.0:1 和 1.4:1的5个B:A比值之一。在裸支架置入前，置入后，和第28天时分别用血管内超声(IVUS)精确测定血管的大小。

结果：支架置入前平均血管直径是3.05 (0.31) (SD) mm。支架内新生内膜容积，支架内狭窄容积和支架内最小管腔直径处狭窄横断面面积随着B:A比值增加而显著增加（多级回归检验，p值分别为p<0.001, p = 0.002 and p<0.001）且不依赖于血管大小。甚至较小的血管扩张B:A在1.1:1时就可以引起明显的内膜增生。较大的B:A比值在支架边缘外与更多的新生内膜相关(p = 0.008)。对于同一动物的血管，对于一个既定的B:A比值，新生内膜反应依赖于对动物的处理。

结论：对于IVUS指导下冠脉支架置入术的猪的模型，血管过度扩张会产生反作用。第28天时新生内膜增生与增加的B:A比值强烈相关。此外，当多个支架以不同的B:A比值被置入同一个动物时，血管反应不是各自独立的。

Coronary artery overexpansion increases neointimal hyperplasia after stent placement in a porcine model

Robert J Russo1, Patricia D Silva1, Mark Yeager1,2

1 Division of Cardiovascular Diseases, Scripps Clinic, La Jolla, CA, USA
2 Department of Cell Biology, The Scripps Research Institute, La Jolla, CA, USA

ABSTRACT

Objective: To determine if an aggressive approach to coronary revascularisation with oversized balloons is counterproductive, we studied the effect of increasing balloon-to-artery (B:A) ratio on neointimal hyperplasia following primary stent placement using a non-atherosclerotic porcine coronary overstretch model.

Methods: 60 vessels in 33 Yorkshire swine were randomly assigned to one of five B:A ratios between 1.0:1 and 1.4:1. Intravascular ultrasound (IVUS) imaging was performed before bare-metal stent placement to accurately determine vessel size, after stent placement, and at 28 days.

Results: The mean prestent vessel diameter was 3.05 (0.31) (SD) mm. In-stent neointimal volume, in-stent volume stenosis and cross-sectional area stenosis at the stent minimum lumen diameter increased significantly with increasing achieved B:A ratio (multilevel regression test for slope, p<0.001, p = 0.002 and p<0.001, respectively) and were independent of vessel size. Even minor vessel overstretch at an achieved B:A ratio of 1.1:1 resulted in significant neointimal hyperplasia. Larger B:A ratios were also associated with more neointima beyond the stent edges (p = 0.008). For vessels from the same animal, neointimal response at a given B:A ratio was dependent upon the animal treated.

Conclusions: In a porcine model of IVUS-guided coronary primary stent placement, vessel overexpansion is counterproductive. Neointimal hyperplasia at 28 days is strongly associated with increasing B:A ratio. In addition, vessels do not respond independently of each other when multiple stents are placed within the same animal using a range of B:A ratios.

Heart 2007; 93: 1609-1615.