Shah Vivek M, Mintz Gary S, Apple Sue, Weissman Neil J
Intravascular Ultrasound Imaging and Cardiac Catheterization Laboratories, Cardiovascular Research Institute, Washington Hospital Center, Washington, DC 20010, USA.
Circulation. 2002 Oct 1;106(14):1753-5. doi: 10.1161/01.cir.0000035239.90657.b1.
Late stent malapposition has been reported to be an abnormal finding after vascular brachytherapy and, possibly, implantation of drug-eluting stents. It can only be detected if intravascular ultrasound (IVUS) is performed at follow-up. However, the "background" frequency of late stent malapposition after bare-metal stent implantation is not known.
We studied 206 patients with native artery lesions who had tubular-slotted bare-metal stent implantation and who had IVUS performed at index and after 6+/-3 months of follow-up. There were 9 patients (4.4%) with late malapposition, which is separation of at least 1 stent strut from the arterial wall intima that does not overlap a side-branch, with evidence of blood flow (speckling) behind the strut, and where the immediate postimplantation IVUS revealed complete apposition of the stent to the vessel wall. The location of late malapposition was the stent edge in 8 of 9 patients. The maximum area, length, volume, and arc of late malapposition measured 3.1+/-2.4 mm(2), 3.3+/-2.2 mm, 21+/-27 mm(3), and 110+/-61 degrees, respectively. There was an increase in external elastic membrane (EEM) area (20.7+/-4.9 to 26.9+/-4.2 mm, P=0.0021) and plaque area (10.1+/-3.7 to 14.8+/-3.6 mm, P=0.0022); however, the increase in EEM was greater than the increase in plaque. The area of late malapposition correlated directly with the increase in EEM area (r=0.75, P=0.0205).
Late malapposition occurs in 4% to 5% of slotted-tube bare-metal stents, usually at stent edges. The main cause is positive remodeling out of proportion to the increase in peri-stent intimal hyperplasia.
晚期支架贴壁不良据报道是血管近距离放射治疗以及可能的药物洗脱支架植入后的一种异常表现。只有在随访时进行血管内超声（IVUS）检查才能检测到。然而，裸金属支架植入后晚期支架贴壁不良的“背景”发生率尚不清楚。
我们研究了206例患有天然动脉病变并植入管状开槽裸金属支架的患者，这些患者在植入时及随访6±3个月后接受了IVUS检查。有9例患者（4.4%）出现晚期贴壁不良，即至少有一个支架撑条与动脉壁内膜分离，且不与侧支重叠，在撑条后方有血流（斑点）迹象，且植入后即刻IVUS显示支架与血管壁完全贴合。9例患者中有8例晚期贴壁不良位于支架边缘。晚期贴壁不良的最大面积、长度、体积和弧度分别为3.1±2.4mm²、3.3±2.2mm、21±27mm³和110±61度。外弹力膜（EEM）面积（从20.7±4.9mm增加到26.9±4.2mm，P = 0.0021）和斑块面积（从10.1±3.7mm增加到14.8±3.6mm，P = 0.0022）均有增加；然而，EEM的增加大于斑块的增加。晚期贴壁不良面积与EEM面积的增加直接相关（r = 0.75，P = 0.0205）。
4%至5%的开槽管状裸金属支架会出现晚期贴壁不良，通常发生在支架边缘。主要原因是正性重构与支架周围内膜增生的增加不成比例。
