低频高能超声血管成形术的基础与临床研究

【作者】 宋耀明；

【导师】 何作云；

【作者基本信息】 第三军医大学 ， 内科学， 2001， 博士

【摘要】 超声血管成形术是近年来引起国内外学者关注的一种新的血运重建方式，采用低频高能超声的机械振动、空化作用等效应裂解粥样硬化斑块、消融血栓、恢复闭塞血管的再通，而对正常血管壁各层结构几乎无损伤。本研究的目的在于：①.通过对低频高能超声作用后动物模型血管平滑肌细胞（VSMC）C-sis表达水平、血小板衍生生长因子（PDGF）、细胞增生状态的评价，明确低频高能超声对平滑肌细胞增殖效应的影响；②应用低频高能超声消融体外全血细胞血栓及体内急性心肌梗塞死、陈旧性心肌梗死患者，观察超声消融血栓的效果、安全性；③体内超声消融冠脉重度狭窄，研究低频高能超声对粥样硬化斑块消融的效果。 本研究实验兔分为正常对照组、试验对照组、球囊损伤组、超声消融组。后二组分别在颈动脉损伤后48h、72h、96h、120h、1w、2w，取目标段动脉约4cm，分成4份，长度各约1cm。制备后采用RT-PCR法测定C-sis mRNA表达、~3H-TdR掺入法测定SMC DNA合成含量、免疫组织化学染色法计算PDGF β-阳性指数、PCNA阳性指数。观察球囊损伤、低频高强度超声对平滑肌细胞增殖效应的影响。结果发现，超声消融组、正常对照组与试验对照组VSMC的C-sis表达、PDGF-βmRNA含量、PCNA染色及~3H-TdR掺透量均无显著增加；而球囊损伤的兔VSMC各时相点均有C-sis表达，其高峰期出现在球囊损伤1周，表达量增高了6.5倍。48h开始出现PDGF、PCNA阳性VSMC细胞，1周时相点达到峰值。72h开始氚掺透值持续升高，至1周达高峰。 采集正常人静脉血2ml制备为全血细胞凝块20例并行重量测定。应用40KHz，18W/cm~2脉冲式超声对全血细胞凝块消融。消融后取沉淀涂片，显微镜下检查碎块大小，并与红细胞直径比较。结果发现，超声能量释放15秒内血栓完全溶解，溶解速度为0二兆土0刀N七。显微镜下检查90％的碎片直径小于红细胞直径。 应用低频高能超声通过导管技术对急性心肌梗死、陈旧性心肌梗死及其PTCA失败的患者进行消融，观察消融前后闭塞相关血管（IRA）TIMI血流改变并利用 SHIMADZU Dghtex a 2400计算机分析系统测量残余狭窄程度，检测手术前后CK－MB、心电图ST段及临床症状的改变，评价低频高能超声血管成形术治疗心肌梗死的可行性。测定消融前后静脉血中PL＊P＊T、卜PA、PA 的含量及观察超声消融中有无冠状动脉痉挛。撕裂等影像学改变。结果发现，10例 AMI患者中消融后 9例 IRA达到 TIMI血流3级，开通率为90％（9／10）。10分钟后9例患者胸痛消失、ST段下降）50％，CK－MB峰值明显前移（5石士1．二小时）。2例患者超声消融后冠状动脉造影闭塞相关血管管腔大于非狭窄段，30分钟后造影残余狭窄分别为 24o、180。8例 OMI患者中，7例消融后 IRA达 TIMI血流 3级，开通率为87．5％（／8），30分钟后造影闭塞相关血管TIMI仍为3级。术后30分钟缺血性盯段下移明显好转（上移350o）。5例常规PTCA失败患者经超声消融，IRA均达 TIMI3级，残余狭窄为 64石土 12石4％。 低频高能超声通过导管技术对冠脉重度狭窄进行消融，比较消融前后冠脉狭窄程度的改变，分析手术前后常规心电图ST段改变，手术前后运动试验测定诱发心绞痛所需时间、运动诱发 ST段下降 0．lmV所需时间、运动诱发ST段下降最大幅度的比较。结果发现，15支狭窄口75％的血管消融后残余狭窄为 43．03 i 15．49o，较术前降低 42．030（43．03士15．49％VS85．83土5．44％，p＜0．05），5例消融后残余狭窄＜30％ （3．33％，5／15）。术后心电图缺血性ST段压低较术前明显好转。术后运动诱发心绞痛所需时间及运动诱发 ST段下降 0．lmV所需时间、运动诱发 ST段下降最大幅度与手术前比较均有显著差异（P＜0．01）。 本研究结论：1．低频高能超声作用后VSMC的增生、迁移无显著改变。2．体外实验及临床病例研究证实低频高能超声能有效溶解新鲜及陈旧性血栓，无血管损伤、微栓塞等严重并发症，对凝血、纤溶系统无不良影 Vll ￡响。3．低频高能超声血管成形术治疗AMI、OMI，可使IRA早期再通，恢复TIMI级血流，是一种新的冠脉血运重建方式。4．血管闭塞时间长，常规PTCA失败的病例，超声血管成形术能成功再通闭塞血管，提高PTCA的成功率。5．超声能量可以有效裂解粥样硬化斑块，但仍然存在血管残余狭窄；与球囊扩张联合应用能够降低所需压力，改善术后再狭窄。6．低频高能超声的血管舒张作用，提高了超声血管成形术的可操作性及安全性。更多还原

【Abstract】 An experimental and clinical study on angioplasty with lowfrequency and high-energy ultrasoundsUltrasonic angioplasty, as a new approach for reconstruction of blood supply, has attracted attention from researchers at home and abroad in recent years. For this technique, such effects as mechanical vibration and cavitation etc. exerted by low frequency and high-energy ultrasounds (LFHEU) are employed to restore potency of blood vessels by splitting atherosclerotic plaques and dissolving thrombi. Meanwhile, the technique does not damage normal vascular structure. This study was designed to investigate angioplasty with LFHEU. The purposes and brief procedures are as follows: 1) After vascular smooth muscle cells (VSMC) in an animal model were treated with LFHEU, expression of C-sis and platelet-derived growth factor (PDGF) and proliferation state of the cells were evaluated to determine effects of LFHEU on proliferation of smooth muscle cells. 2) LFHEU was used to dissolve panhematic thrombi formed in vitro and those in patients with acute myocardial infarction or old myocardial infarction to determine its safety and efficiency in dissolving thrombi. 3) LFHEU was used to treat serious stenosis of the coronary artery to investigate its dissolving effects on atherosclerotic plaques.In this study, rabbits were randomized into normal control group (group A), experimental control group (group B), balloon-injured group (group C) and ultrasonic dissolved group (group D). After the injury in carotid artery, the target segment of the common carotid artery with a length of 4 cm in rabbits in the latter two groups was extracted at 48, 72, 96, 120 hours and 1 and 2 weeks, respectively. The segment was divided into 4 parts with a length of approximately 1 cm in each. Expression of C-sis mRNA was determined by RT-PCR, synthesis and content of DNA in smooth muscle cells measured by 3H-TdR incorporation and positive indexes of PDGF-~ and PCNA by PDGF-~and PCNA immunohistochemical staining to determine effects of ballooninjury and LFHEU on proliferation of smooth mu5cle cel1s. It was fOund thatthere were no expression of C-sis and significant increase in the conteflt ofPDGF-0, PCNA staining and incorporation of 3H-TdR in Group A, Group Band Group D. In Group C, typical expression of C-sis of cytokines encodingPDGF-0 appeared and its peak was found in l week after the injury. Theexpression intensity was increased for 6.5 times. PDGF-positive smoothmuscle ce1ls began to aPpear at 48 hours and the number reached its peak at 1week after the injury. Incorporation value of tritium began to be continuouslyelevated in 72 hours and reached its peak at 1 week after the injury.Venous blood of 2 ml was collected from volunteers to prepare 20panhematic c1ots. Then the colt was weighed. Ultrasounds of 40 KHz and l8Wcm2 was used to dissolve the clots till its disaPpearance. After the dissolvedsubstance was made stationary, the supernatant was discarded and sedimentcol1ected for smear examination under the microscope. Microscopicexamination revealed that the diameter of 90% of pieces produced in dissolvewas smaller than that of red blood cells and prepared panhematic clots werecompletely dissolved in l5 seconds (dissolving speed = 0. 13 8 i 0.018g/s).LFHEU was introduced via catheterization to treat patients with acutemyocardial infarction, old myocardial infarction and those with old myocardialinfarction in whom PTCA failed. Degree of residual stenosis was measured andanalyzed with SHIMADZU Digitex a 2400 computerized analyzing system andchanges in blood flow in infarction-related arteries (IRA), CK-MB after thetreatment, ST segmeni in ECG and clinical manifestations were observed toevaluate feasibility of using angioplasty with LFHEU to treat myocardialinfarction. Safety of ultrasonic angioplasty was exp1ored by measuring contentsof PT, APTT t-PA and PAI in venous blood before and after the treatment todetermine whether there were imaging changes such as coron更多还原