Mudra H, Klauss V, Blasini R, Kroetz M, Rieber J, Regar E, Theisen K
Department of Medicine, Klinikum Innenstadt, University of Munich, Germany.
Circulation. 1994 Sep;90(3):1252-61. doi: 10.1161/01.cir.90.3.1252.
Coronary stenting in conjunction with coronary angioplasty is a valuable tool for treatment of severe coronary dissection and is effective in reducing the frequency of restenoses. Evidence is increasing that the lumen gain within the stent is negatively correlated with the rate of subacute closures and restenoses. Since the assessment of radiolucent coronary stents and complex lumen morphologies by angiography is limited, we hypothesized that the use of a balloon catheter with integrated intravascular ultrasound (IVUS) facility for stent deployment and guidance of its expansion could improve the acute lumen gain without relevant procedural prolongation.
Deployment of a single Palmaz-Schatz coronary stent with the combined imaging balloon catheter alone was successful in 18 of 20 patients eligible for this study. Corresponding measurements of minimal lumen diameter (MLD) by angiography and IVUS could be performed in 16 patients, revealing a close correlation between the two methods within the reference segments (3.10 +/- 0.38 and 3.08 +/- 0.43 mm, r = .79). Despite an adequate angiographic result in most patients after stent deployment, IVUS showed smaller MLD within the stented segment (2.15 +/- 0.23 mm) compared with angiography (2.63 +/- 0.26 mm, P < .0001) with a poor correlation (r = .27). To achieve IVUS criteria for optimal stent expansion (ratio of 0.9 between IVUS-assessed cross-sectional area of stent and reference segment), an average of three additional balloon inflations with higher pressure and/or a larger balloon diameter were performed without adverse effects in 15 of 16 patients who initially did not fulfill these criteria. This resulted in a significant increase in stent MLD to 2.63 +/- 0.27 mm (IVUS, P < .0001 versus initial MLD) and 2.89 +/- 0.32 mm (angiography, P < .0002 versus initial MLD) and a better correlation between the two methods (r = .60). The IVUS guidance led to a 40 +/- 15% increase of the minimal stent cross-sectional area with an additional time consumption of 21 minutes on average.
This study demonstrates the application of a combined imaging balloon catheter for delivery and ultrasound-guided expansion of Palmaz-Schatz coronary stents. IVUS offered a comprehensive insight into the stented coronary segments, revealing a substantial overestimation of stent dimensions by angiography. IVUS guidance led to a significant improvement of stent expansion. This additional lumen gain, which was not discernible by angiography in most patients, might result in a reduction of subacute stent thromboses as well as restenoses.
冠状动脉支架置入术联合冠状动脉血管成形术是治疗严重冠状动脉夹层的一项重要手段，且在降低再狭窄发生率方面效果显著。越来越多的证据表明，支架内管腔增益与亚急性闭塞和再狭窄发生率呈负相关。由于血管造影对不可显影冠状动脉支架及复杂管腔形态的评估有限，我们推测，使用带有集成血管内超声（IVUS）设备的球囊导管进行支架置入及其扩张引导，可在不显著延长手术时间的情况下改善急性管腔增益。
在符合本研究条件的20例患者中，单独使用联合成像球囊导管成功置入单个帕尔马兹-施查茨冠状动脉支架的有18例。16例患者可通过血管造影和IVUS对最小管腔直径（MLD）进行相应测量，结果显示在参考节段内两种方法具有密切相关性（分别为3.10±0.38和3.08±0.43mm，r = 0.79）。尽管大多数患者在支架置入后血管造影结果良好，但IVUS显示支架节段内的MLD（2.15±0.23mm）小于血管造影结果（2.63±0.26mm，P < 0.0001），且相关性较差（r = 0.27）。为达到IVUS最佳支架扩张标准（IVUS评估的支架横截面积与参考节段之比为0.9），在最初未达标的16例患者中，有15例平均额外进行了三次更高压力和/或更大球囊直径的球囊充气，且未出现不良反应。这使得支架MLD显著增加至2.63±0.27mm（IVUS，与初始MLD相比P < 0.0001）和2.89±0.32mm（血管造影，与初始MLD相比P < 0.0002），且两种方法之间的相关性更好（r = 0.60）。IVUS引导使最小支架横截面积增加了40±15%，平均额外耗时21分钟。
本研究展示了联合成像球囊导管在帕尔马兹-施查茨冠状动脉支架输送及超声引导扩张中的应用。IVUS能全面了解冠状动脉支架置入节段情况，显示血管造影对支架尺寸存在明显高估。IVUS引导使支架扩张得到显著改善。这种大多数患者血管造影无法察觉的额外管腔增益，可能会降低亚急性支架血栓形成以及再狭窄的发生率。
