Werner G S, Diedrich J, Schünemann S, Gastmann O, Ferrari M, Buchwald A B, Figulla H R, Kreuzer H
Department of Cardiology, Georg-August-University, Göttingen, Germany.
Int J Card Imaging. 1997 Aug;13(4):311-21. doi: 10.1023/a:1005703626872.
Studies by intravascular ultrasound demonstrated inadequate expansion in a large number of stents, which lead to the increase of inflation pressure for stenting. The present study examined whether routine use of high-pressure inflation would be sufficient for an optimum stent expansion without sonographic guidance.
Two types of single coronary stents (Palmaz-Schatz in 54, and Wiktor in 25) were implanted with inflation pressures of 16-20 atm in 79 nonocclusive coronary lesions. IVUS before stenting was used in 78% to select the adequate stent size. Intravascular ultrasound after stenting was used to asses the minimum stent are and diameter, the reference areas, and the strut apposition to the vessel wall. The difference between the area of the expanding balloon and the stent area was calculated as the luminal deficit of the stent. Completeness of stent expansion required full strut apposition and lesion coverage, and a minimum stent area that was larger than the distal reference, and larger than 60% of the proximal reference. Intravascular ultrasound before stenting lead to an increase of the stent size in 47%. After high-pressure expansion, even with the optimized balloon size, 8% of stents had struts protruding into the lumen. The stent area (6.87 +/- 1.93 mm2) was significantly smaller than both the proximal (9.59 +/- 2.91 mm2; p < 0.001) and distal reference area (8.23 +/- 3.03 mm2; p < 0.001). The criteria for complete expansion were met in 48%. The expansion with a larger high-pressure balloon in 28 stents lead to an increase of the stent area by 19% (8.19 +/- 2.24; p < 0.001), and full stent apposition in all cases. The criteria of stent expansion were met in 82%. A wide range of the luminal deficit upto 48% was observed, which was not related to sonographic lesion characteristics, except in lesions with complete circumferential calcifications. The different stent designs were characterized by a slightly lower luminal deficit in slotted-tube stents (23 +/- 13% vs. 28 +/- 12%; p = 0.11) and a better index of stent symmetry as compared with the coil stent (0.87 +/- 0.08 vs. 0.82 +/- 0.09; p < 0.05).
Routine use of high-pressure stent expansion did not lead to a sufficient stent expansion, even when the initial stent size had been guided by intravascular ultrasound. Further stent dilatation with larger balloons under ultrasound guidance would be required to optimize the luminal area gain.
血管内超声研究表明，大量支架扩张不充分，这导致支架置入时膨胀压力增加。本研究探讨在无超声引导的情况下，常规使用高压膨胀是否足以实现最佳支架扩张。
在79处非闭塞性冠状动脉病变中，以16 - 20个大气压的膨胀压力植入两种类型的单冠状动脉支架（54个Palmaz-Schatz支架和25个Wiktor支架）。78%的病例在支架置入前使用血管内超声来选择合适的支架尺寸。支架置入后使用血管内超声评估最小支架面积和直径、参考面积以及支架支柱与血管壁的贴合情况。将扩张球囊面积与支架面积之差计算为支架的管腔缺损。支架完全扩张的标准要求支柱完全贴合且覆盖病变，最小支架面积大于远端参考面积且大于近端参考面积的60%。支架置入前的血管内超声使47%的病例支架尺寸增大。高压扩张后，即使使用优化的球囊尺寸，仍有8%的支架支柱突入管腔。支架面积（6.87±1.93平方毫米）显著小于近端参考面积（9.59±2.91平方毫米；p<0.001）和远端参考面积（8.23±3.03平方毫米；p<0.001）。48%的病例达到完全扩张标准。对28个支架使用更大的高压球囊进行扩张，使支架面积增加了19%（8.19±2.24；p<0.001），且所有病例中支架均完全贴合。82%的病例达到支架扩张标准。观察到管腔缺损范围广泛，可达48%，除完全环形钙化病变外，这与超声病变特征无关。不同的支架设计特点是，与线圈支架相比，开槽管支架的管腔缺损略低（23±13%对28±12%；p = 0.11），且支架对称性指数更好（0.87±0.08对0.82±0.09；p<0.05）。
即使初始支架尺寸由血管内超声引导，常规使用高压支架扩张也不能实现充分的支架扩张。需要在超声引导下使用更大的球囊进一步扩张支架，以优化管腔面积增益。
