Waksman R, Robinson K A, Crocker I R, Gravanis M B, Palmer S J, Wang C, Cipolla G D, King S B
Andreas Gruentzig Cardiovascular Center, Department of Medicine, Atlanta, Ga., USA.
Circulation. 1995 Sep 15;92(6):1383-6. doi: 10.1161/01.cir.92.6.1383.
Stent implantation has been shown to reduce restenosis by establishing a larger lumen but not by reducing neointima formation. We have previously shown that ionizing radiation reduced neointima formation after balloon injury in a swine model of restenosis. The purpose of this study was to determine whether endovascular irradiation of the coronary artery before stent implantation would affect neointima formation.
Nine normolipemic pigs underwent coronary angiography, and segments of the left anterior descending and left circumflex arteries were chosen as targets for stenting. A high-activity 192Ir source was used to deliver 14 Gy by random assignment to one of the vessels. After this, 3.5-mm tantalum stents were implanted in both arteries. Three additional pigs were treated with a 90Sr/Y source (a pure beta-emitter) delivering 14 Gy to five segments of coronary vessels that were stented immediately after irradiation. Stent-to-artery ratio was similar in the radiated and the control arteries. Animals received aspirin 325 mg daily and were killed at 28 days. The intimal area was significantly reduced in the irradiated stented arteries compared with control arteries treated with stent only (1.98 mm2 with 192Ir and 2.53 mm2 with 90Sr/Y versus 3.82 mm2 in the control stented arteries, P < .005).
Endovascular radiation before coronary stenting reduces neointima formation and may further reduce the restenosis rate after stent implantation.
支架植入已被证明可通过建立更大的管腔来减少再狭窄，但不能通过减少新生内膜形成来实现。我们之前已经表明，在猪再狭窄模型中，电离辐射可减少球囊损伤后的新生内膜形成。本研究的目的是确定在支架植入前对冠状动脉进行血管内照射是否会影响新生内膜形成。
9只血脂正常的猪接受冠状动脉造影，左前降支和左旋支动脉段被选为支架植入靶点。通过随机分配，使用高活性192铱源向其中一根血管输送14 Gy剂量。此后，在两根动脉中均植入3.5毫米的钽支架。另外3只猪接受90锶/钇源（一种纯β发射体）治疗，向5段冠状动脉输送14 Gy剂量，照射后立即在这些血管段植入支架。辐射血管和对照血管的支架与动脉比例相似。动物每天接受325毫克阿司匹林治疗，并在28天时处死。与仅接受支架治疗的对照血管相比，接受照射的支架植入血管内膜面积显著减小（192铱照射组为1.98平方毫米，90锶/钇照射组为2.53平方毫米，而对照支架植入血管为3.82平方毫米，P <.005）。
冠状动脉支架植入前的血管内辐射可减少新生内膜形成，并可能进一步降低支架植入后的再狭窄率。
