血管内超声显像在冠状动脉粥样硬化性心脏病支架置入中的应用（英文）

背景：支架扩张不充分以及与操作相关的异常病变形态是支架内再狭窄以及急性、亚急性和慢性支架内血栓形成的重要原因。目的：观察应用血管内超声指导支架置入能否获得更大的支架内管腔面积,能否发现更多与操作相关的并发症。设计、时间及地点：回顾性病例分析,于2004-01/2005-02在首都医科大学附属北京朝阳医院心脏中心进行。对象：选择50例患者的52处在血管内超声指导下行支架置入的病变进行分析。入选患者均为自体冠状动脉非弥漫性病变,血管直径≥2.5mm,严重的左主干病变除外。方法：50例患者的52处病变在支架置入前后分别用血管造影和血管内超声进行定量和定性分析,并根据血管内超声标准决定支架的直径以及置入的终点。主要观察指标：分析血管造影和血管内超声对支架置入终点判断的差异和最终获得的管腔面积大小的差别。结果：①血管内超声判断的平均支架直径大于血管造影（P=0.011）,支架囊的最终峰值压力明显增大（P〈0.001）,定量冠状动脉造影测得的支架面积狭窄百分比减小（P=0.044）。②首次高压扩张后支架满意率血管造影达96.2%,而血管内超声只有37.7%。③血管内超声指导后最终的球囊压力更高（P〈0.001）,获得的管腔直径更大（P〈0.001）,管腔面积也更大（P〈0.001）,面积狭窄百分比更小（P〈0.001）。④所有患者支架的近段和远段血管造影均未发现明显的狭窄。而血管内超声却发现支架近段血管有39例（75.0%）,远段血管有23例（44.2%）存在动脉粥样硬化斑块。⑤支架置入后非脂质斑块较脂质斑块获得的管腔面积更大（P〈0.001）,其中脂质斑块血管面积增大较非脂质斑块小1.30mm^2,斑块压缩程度却增加0.48mm^2。结论：血管内超声能更好地指导支架选择,获得更大的管腔面积,也能更精确地发现操作相关的并发症。     

血管内超声与冠状动脉造影在冠状动脉支架置入中的应用比较

目的:冠状动脉支架置入已成为治疗冠状动脉狭窄性病变的主要方法,支架治疗策略的选择成为主要技术问题,文章对冠脉造影后的血管狭窄分析和血管内超声成像的血管分析应用效价进行探讨.方法:根据文献报道对冠状动脉造影血管狭窄分析及血管内超声在冠脉支架置入前后的应用,结合南昌大学第二附属医院冠状动脉支架置入前后的血管造影及血管内超声的应用进行对比分析.结果:冠状动脉造影对支架置入前后的影像学造影检查,只能观其血管外壁形态、血流变化.对管腔黏膜病变情况、内支架贴壁情况,支架是否完全对称性扩张,以及支架对病变段的覆盖情况,不能精确显示.血管内超声对靶血管的狭窄程度、血管内斑块及黏膜病变情况能够精确实时显示,可实时显示支架是否完全扩张,支架扩张是否均匀对称,支架对血管壁斑块的挤压支撑情况如何.结论:血管内超卢在冠脉支架置入前后的应用,较冠状动脉造影更能全面的评价血管内病变情况,对支架的选取策略及支架释放后的评价与指导,防止血管内再狭窄具有重要的意义.     

造影正常冠状动脉左主干的血管内超声研究

目的 探讨冠状动脉造影正常左主干的血管内超声特征.方法 选取冠状动脉造影显示单纯左前降支或左回旋支病变而左主干正常同时行血管内超声(IVUS)检查的76例患者.应用IVUS测量病变部位的斑块负荷,确定斑块的性质.同时确定左主干是否存在病变,若存在病变则确定病变性质;测量左主干的管腔直径和面积以及血管直径和面积;对存在动脉粥样硬化者,测量斑块负荷.结果 76例冠状动脉造影正常左主干患者中IVUS显示完全正常28例,内膜增生12例,有斑块36例,发现内膜斑片2例.对于存在斑块者偏心斑块为30例,向心斑块为6例;脂质斑块25例(占69.4%),纤维斑块4例(占11.1%),钙化斑块2例(占5.6%),混合斑块5例(占13.9%).IVUS显示女性左主干正常者的管腔直径为(5.32±0.68)mm,管腔面积为(23.34±5.27)mm2,男性左主干正常者的管腔直径为(5.90±0.50)mm,管腔面积为(27.75±4.47)mm2.男女管腔直径和管腔面积比较差别均有统计学意义(P值分别为0.042和0.048).内膜增生者血管直径为(5.90±0.47)mm,血管面积为(27.58±4.21)mm2;存在斑块者的管腔直径为(4.39±0.54)mm,管腔面积为(17.45±5.23)mm2,血管直径为(5.99±0.67)mm,血管面积为(26.61±6.27)mm2,直径狭窄百分比为(26.17±7.87)%,斑块负荷为(34.79±9.37)%.结论 IVUS能发现冠状动脉造影所无法显示的左主干病变,并且能精确地确定左主干病变的性质和严重程度.     

血管内超声指导小血管病变支架置入的临床应用

目的　观察血管内超声指导小血管病变支架置入的临床疗效 ,评价其应用价值。方法　 10 2例冠脉造影确定的小血管病变患者 ,随机分为冠脉造影指导组 (冠脉造影组 )和血管内超声指导组 (超声组 ) ,血管内超声组在血管内超声指导下置入支架 ,冠脉造影组在单纯冠脉造影指导下置入支架 ,根据各自不同的判定标准 ,对支架置入达不到理想标准的再次行高压球囊扩张或加置支架。在支架置入前、置入后即刻和术后 6个月不同时间定量冠脉造影测定病变长度、直径或面积狭窄率、病变最小血管直径 (MLD)、参照血管直径 ,观察 6个月内的再狭窄率和不良心血管事件。结果　冠脉造影组 5 2例患者 4 9例成功置入支架 ,超声组 5 0例患者全部完成血管内超声检查 ,4 8例成功置入支架。超声组和冠脉造影组比较 :支架置入前 ,两组所选支架长度、内径大小有显著差异 ;支架置入后即刻 ,超声组和冠脉造影组病变MLD分别是 (2 .78± 0 .30 )mm、(2 .5 0± 0 .2 7)mm ,直径狭窄率分别是 (8± 3) %、(12± 5 ) % (P <0 .0 1) ;6个月随访时超声组和冠脉造影组再狭窄率分别是 2 5 %、4 6 % (P <0 .0 1) ,总不良心血管事件分别是 6例(12 % )和 17例 (32 .7% ) (P <0 .0 5 )。结论　血管内超声指导小血管病变支架置入能获得较好的临床效果 ,安     

血管内超声在冠脉内支架植入术中的临床应用

目的:通过血管内超声(IVUS)评价冠脉内支架植入前后动脉壁形态学改变及斑块形态对支架膨展的影响,探讨该技术在支架植入术中的临床应用价值.方法:15例冠心病患者在支架植入前后靶病变处,使用30MHz、2.9F机械旋转式超声导管施行IVUS成像.测量支架植入前后靶病变处外弹力膜横截面积、斑块+中膜面积及腔面积,并评价血管壁的形态学特点.结果:15处靶病变在支架植入前后血管造影直径狭窄百分比由76±11%降至8±10%.超声上,外弹力膜面积由支架植入前的10.8±3.6mm2增至14.1±2.9mm2,斑块面积则从8.3±1.4mm2降至6.5±1.6mm2(P均＜0.01),而管腔面积由于外弹力膜面积增加及斑块面积的缩小,由植入前的4.5±1.8mm2增至6.5±2.3mm2(P＜0.05).15处靶病变中,钙化斑块、纤维混合斑块、软斑块分别为3例,8例,4例.偏心班块占73.3%,同心斑块26.7%.IVUS发现PTCA后87%(13/15)存在夹层,其中一些伴有管腔内的小内膜片,而造影则为40%(7/15).符合IVUS支架植入最佳标准者占27%(4/15).有3例(20%)在支架边缘处发现存在内膜撕裂或小裂隙.1例在操作过程中冠脉痉挛,导管后撤及冠脉内注入硝酸甘油后消失.结论:IVUS在发现PTCA术后血管夹层方面比CAG更加敏感.冠脉支架植入后,血管的伸展和斑块的减少均参与了管腔的增加.钙化病变影响支架的最佳膨展.此技术安全可行,可用来指导支架的植入.     

冠状动脉造影和血管内超声在诊断变异型心绞痛中的临床价值

目的 探讨冠状动脉造影、血管内超声在诊断变异型心绞痛患者中的临床价值.方法 选择我院2007年12月至2009年3月临床诊断为冠心病患者23例,其中变异型心绞痛患者10例,稳定型心绞痛患者13例.对每位患者行冠状动脉造影及血管内超声检查,对病变斑块的性质、形态、部位、血管管腔面积狭窄程度、血管重构指数等指标进行分析.结果 变异型心绞痛组与稳定型心绞痛组两组斑块偏心指数分别为0.90±0.06 vs 0.70±0.25,局部面积狭窄率分别为(53.56±3.88)%vs(68.66±14.52)%,管腔面积狭窄率分别为(41.23±23.91)%vs(63.10±14.64)%,以上指标两组差异有统计学意义(均P<0.05).血管内超声检测病变血管重构指数,正性重构、负性重构在两组差异有统计学意义(P<0.05).对于变异型心绞痛患者,以血管内超声为参照,以节段为基础,冠状动脉造影和血管内超声检测血管管腔平均狭窄程度差异有统计学意义(P<0.05).冠状动脉造影和血管内超声检测轻中度管腔面积狭窄差异有统计学意义,重度管腔面积狭窄两者差异无统计学意义.结论 变异型心绞痛患者冠状动脉目标斑块以偏心性斑块为主,血管管腔面积狭窄程度以轻中度狭窄为主,血管重构以正性重构为主.冠状动脉造影低估病变管腔面积狭窄程度.     

血管内超声在心脑血管支架置入中的应用

冠状动脉支架置入治疗冠状动脉狭窄前对病变的狭窄程度、病变性质、病变范围的准确判断是支架置入方案选择的关键.最佳冠脉内支架置入方案,能有效的降低支架置入后再狭窄,提高冠脉疾病介入治疗的效果.血管内超声对靶阻管的狭窄程度、血管内斑块及黏膜病变情况能够精确实时显示,包括支架是否完全扩张,支架扩张是否均匀对称,支架对血管壁斑块的挤压支撑情况如何.说明血管内超声在冠状动脉支架置入前后的应用,较冠状动脉造影更能全面的评价血管内病变情况,对支架的选取策略及支架释放后的评价与指导,防止血管内再狭窄具有重要的意义.     

急性冠脉综合征临界病变易损斑块变化与超敏C反应蛋白的关系

目的:探讨急性冠脉综合征(ACS)临界病变斑块血管内超声影像学特征与血清超敏C反应蛋白的关系,方法:入选因ACS入院患者,入院后行冠脉造影、对病变为临界病变,未行介入治疗者,入选后给与冠心病二级预防,入选后1个月内及入选后12个月行血管内超声检查,评估斑块特征.抽血检测C反应蛋白.对患者靶血管内超声特征与血清高敏感C反应蛋白(high sensitive C-reactive protein,hsCRP)、进行相关研究.结果:轻中度狭窄组血管内超声检出脂质斑块51例(82.26%,51/62),其病变的血管外弹力膜面(EEMA)、斑块面积(PA)及管腔面积狭窄率(LAS)、重构指数(RI)明显大于重度狭窄组,差异有显著性意义(均P<005).两组间在纤维帽厚度、脂核或无回声带大小、脂核与斑块比存在统计学差异.hsCRP与EEMA、RI呈正相关.结论:易损斑块为偏心分布的低回声脂质斑块.具有较大的斑块面积和明显的正性重构:hsCRP可望作为冠脉斑块易损性预测的参考指标.     

冠状动脉临界病变粥样硬化易损性斑块血管内超声特征及分子机制的研究

目的 探讨不稳定型心绞痛患者冠状动脉临界病变粥样斑块的血管内超声特征及外周血CD36、Fractalkine及LP-PLA2水平变化与冠脉病变程度的关系.方法 选择不稳定型心绞痛患者120例,根据冠状动脉造影结果分为:严重病变组(管腔狭窄率＞70％)40例及临界病变组(管腔狭窄50％～70％)80例.应用血管内超声检测两组患者冠脉斑块的性质、外弹力膜面积(EEMA)、管腔面积(LA)、斑块面积(PA)、斑块负荷(PB)及血管重构指数等并指导冠脉介入治疗.ELISA法测定血清CD36、Fractalkine及LP-PLA2水平.结果 血管内超声发现临界病变组主要为脂质斑块,约占74％,严重病变组脂质斑块约为48％(P＜0.01);严重病变组病变部位血管的EEMA、PA及PB明显大于临界病变组(P＜ 0.05～0.01),两组患者的病变部位斑块均以偏心斑块为主,均呈现为正性重构.临界病变组进行介入治疗者共59例(74％),介入治疗组病变部位血管的EEMA、PA、PB及RI明显大于非介入组(P＜0.05～0.01).临界病变组与严重病变组CD36水平差异有统计学意义(P＜0.05).结论 不稳定型心绞痛患者的临界病变具有典型的易损斑块的特征,血管内超声能够指导冠脉的介入治疗.CD36可以作为评价冠状动脉粥样硬化斑块严重性的指标.     

血管内超声与血管造影检测早期左冠状动脉主干病变的对比研究

目的:通过血管内超声(IVUS)研究左冠状动脉主干(LMCA)动脉粥样硬化病变的发生率以及血管重塑的效应。方法:41例血管造影正常的LMCA行IVUS检查,计算LMCA的外弹力膜面积(血管面积)、管腔面积、斑块面积以及百分面积狭窄。结果:23例(56％)LMCA含有粥样硬化斑块。74％的斑块呈偏心性。含有斑块的LMCA血管面积19.6mm2±3.8mm2,与斑块面积(6.0mm2±2.7mm2)呈中度正相关(r=0.49,P<0.01)。平均面积狭窄为30.5±12.7％(6.4-68.6％)。含有斑块的LMCA血管面积比无斑块者(15.7mm2±1.9mm2,P<0.001)更大。结论:血管造影低估了LMCA粥样硬化病变的发生率。随着斑块的增长,LMCA出现代偿性扩张。IVUS是检测LMCA病变的重要方法。     

Comparison of intravascular ultrasonic imaging with versus without incomplete stent apposition at follow-up after drug-eluting stent implantation

BACKGROUND: Incomplete stent apposition (ISA) at follow-up has been reported to be more common after drug-eluting stent (DES) implantation than after bare-metal stent (BMS) implantation. The aim of this study was to use intravascular ultrasound (IVUS) to evaluate the coronary characteristics after drug-eluting stent implantation in patients with ISA at follow-up. METHODS: From the IVUS database of our institute, a total of 89 patients with 125 native lesions who underwent DES implantation into de novo lesions with IVUS imaging at 6-month follow-up were identified, and 15 (16.9%) patients had documented ISA at follow-up by IVUS. The ISA group was compared with a matched control group of patients (n = 30) who had no evidence of ISA at follow-up. RESULTS: Of the 15 documented ISA at follow-up after DES implantation, two located at the edge (within 5 mm from stent margin) while 13 in the body of the stent. The maximum area and arc of ISA measured 5.3 +/- 2.2 mm(2) and 163 +/- 67 degrees , respectively. In patients with ISA, the maximum EEM area of stent segment with ISA was significantly larger than the adjacent stent segment without ISA (24.1 +/- 3.3 vs. 20.1 +/- 3.1 mm(2), P = 0.002), while stent area, plaque plus media (P&M) area and intrastent lumen area were comparable (P > 0.05). Compared to the matched control cohort without ISA at follow-up, the maximum EEM area was also significantly larger (24.1 +/- 3.3 vs. 18.8 +/- 4.2 mm(2), P < 0.001), while the areas of reference EEM and lumen, stent, P&M behind the stent, intimal hyperplasia and intrastent lumen were all comparable between the two groups (P > 0.05). CONCLUSION: ISA at follow-up after DES implantation for de novo coronary lesions was associated with a larger EEM area.     

Additional luminal area gain by intravascular ultrasound guidance after coronary stent implantation with high inflation pressure

Aims: Studies by intravascular ultrasound demonstrated inadequate expansion in a large number of stents, which lead to the increase of inflation pressures for stenting. The present study examined whether routine use of high-pressure inflation would be sufficient for an optimum stent expansion without sonographic guidance. Methods and results: 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 assess the minimum stent area 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). Conclusion: 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.     

Early lumen diameter loss after percutaneous transluminal coronary angioplasty is related to coronary plaque burden: a role for viscous plaque properties in early lumen diameter loss

Objectives: We tested the hypothesis that lumen diameter loss within 1 h after percutaneous transluminal coronary angioplasty is related to plaque volume parameters. Background: Early lumen diameter loss after coronary balloon angioplasty may predict restenosis and may paradoxically decrease late lumen diameter loss. Viscous properties of the vessel wall, as would be determined by tissue volume and composition, may be involved in early lumen diameter loss. Methods: Early lumen diameter loss was measured with quantitative coronary angiography as the loss in lesion lumen diameter (significant loss 0.4 mm) occurring between 5 min and a median of 40 min after successful coronary balloon angioplasty in 68 patients. Thirty-nine patients were evaluated with intravascular ultrasound at the narrowest lumen cross-section of the dilated lesion, 29 patients formed a control group without intravascular ultrasound imaging. We tested the relation between intravascular ultrasound parameters and early lumen diameter loss. Results: Early lumen diameter loss of 0.4 mm was present in eight patients (12%), decreasing lumen diameter from 2.26 ± 0.36 mm to 1.73 ± 0.43 mm. There was no difference in the frequency of early lumen diameter loss between the groups with or without intravascular ultrasound imaging. Univariate intravascular ultrasound determinants of early lumen diameter loss were media bounded area (p = 0.01), maximal plaque thickness (p = 0.02), eccentricity index (p = 0.03) and the presence of hard lesions (p = 0.02). Conclusion: Early lumen diameter loss in the first hour after successful coronary balloon angioplasty occurs in a small proportion of patients. It is related to hard lesion type, maximal plaque thickness and eccentricity index, favoring a role for viscous plaque properties in early lumen diameter loss.     

药物球囊治疗冠状动脉支架内再狭窄的临床疗效

目的探讨药物球囊治疗冠状动脉支架内再狭窄后病变血管内膜腔的变化。 方法选取2016年5月至2017年12月确诊的不稳定型心绞痛患者，其在东南大学医学院附属江阴医院曾接受经皮冠状动脉药物洗脱支架植入术，因心绞痛再次接受冠状动脉造影检查，确定为支架内再狭窄的患者96例作为研究对象，将患者分为药物球囊治疗组（47例）及支架植入组（49例），比较术后即刻最小内膜腔面积、支架最小截面积、支架膨胀率等，术后12个月复查冠状动脉造影及血管内超声检查，比较两组心血管事件、最小内膜腔面积、支架最小截面积、内膜增生面积等。 结果经冠状动脉造影及血管内超声检查：药物球囊治组疗术后即刻靶病变最小内膜腔面积和支架最小截面积均小于支架植入组［（10.8±2.8）mm² vs （11.8±3.2）mm²；（11.2±2.9）mm² vs （12.0±3.2）mm²］，差异具有统计学意义（t=2.112、1.987，P=0.025、0.042）；支架相对膨胀率药物球囊治疗组低于支架组（86.7% vs 90.3%），差异具有统计学意义（χ²=2.012，P=0.045）。术后随访12个月，药物球囊治疗组发生心血管事件7例，支架植入组心血管事件9例，2组差异无统计学意义（P=0.699）；药物球囊治疗组与支架植入组支架植入处最小内膜腔面积［（10.6±2.6）mm² vs （10.8±2.7）mm²］比较，差异无统计学意义（P=0.896）；2组患者支架植入处内膜均有增生，但药物球囊治疗组与支架植入组内膜增生面积［（0.30±0.12）mm² vs （0.39±0.15）mm²］比较，差异无统计学意义（P=0.845）；药物球囊治疗组与支架植入组支架最小截面积［（10.9±2.7）mm² vs （11.2±3.0）mm²］比较，差异无统计学意义（P=0.723）。 结论药物球囊治疗支架内再狭窄后12个月其靶病变血管最小内膜腔面积、支架最小截面积、内膜增生面积与支架植入组相当，临床应用安全可靠。     

血管内超声在缺血性脑血管疾病支架置入过程中的应用与评价

目的:脑血管内支架置入已逐渐成为治疗缺血性脑血管疾病一种重要方法,但支架置入后的再狭窄成为当前疾病治疗的主要局限.为此对超声在判断和减少血管支架置入再狭窄的应用效果和价值进行探讨.方法:由第一作者检索维普数据库和中国期刊全文数据库有关缺血性脑血管疾病支架置入的超声评价方面的文献,共检索到22篇文献,对资料进行初审,最终纳入6篇进行分析.纳入标准:①血管内超声在颈动脉支架置入前的应用.②血管内超声指导支架置入及其效果评价.③彩色多普勒超声及经颅彩色多普勒超声对颈动脉支架置入后近期及远期效果的评价.排除标准:较陈旧的文献和重复研究.结果:①血管内超声在支架置入前可精确测量血管管腔的狭窄程度、狭窄长度及血管腔面积,以便选择大小、长度适合的支架,指导支架行之有效的放置.②血管内超声探头可以观察到支架扩张是否完全,扩张后的支架是否对称,精确测量扩张后支架的大小以及支架与血管壁的紧贴程度.③彩色多普勒超声及经颅彩色多普勒超声可以监测血管支架置入后的近期及远期效果,早期发现、早期治疗,减少血管再狭窄的发生.明确血管支架内发生再狭窄的原因,指导对支架内发生再狭窄的治疗,降低再狭窄的发生率,进一步改善支架置入效果.结论:血管内超声弥补了数字减影血管造影的不足,在其指导下的支架置入可获得较大的支架面积和较小的再狭窄率.在血管支架置入后,血管内超声可准确检测支架的扩张程度及血管壁内贴壁情况,彩色多普勒超声及经颅彩色多普勒超声定 期监测支架内的血流情况,对血管内支架置入后再狭窄的评估及预防再狭窄具有重要的应用价值.     

Intravascular ultrasound imaging following balloon angioplasty

Despite its long history and reliability, contrast angiography has several inherent limitations. Because it is a two-dimensional projection image of the lumen contour, the wall thickness cannot be measured and the plaque itself is not visualized. This results in an underestimation of the amount of atherosclerotic disease by angiography. An assessment of atherosclerosis could be improved by an imaging modality: (1) that has an inherent larger magnification than angiography and (2) that directly visualizes the plaque. Intravascular ultrasound fulfils these criteria. This presentation will provide evidence that intravascular ultrasound may prove complimentary or even superior to angiography as an imaging modality. Intravascular ultrasound demonstrates excellent representations of lumen and plaque morphology ofin vitro specimens compared with histology. There is very close intraobserver and interobserver variability of measurements made from intravascular ultrasound images. Phantom studies of stenoses in a tube model demonstrate that angiography can misrepresent the severity of stenosis when the lumen contour is irregular and not a typical ellipse, whereas intravascular ultrasound reproduces the cross-sectional morphology more accurately since it images the artery from within.In vitro studies of the atherosclerotic plaque tissue characteristics compare closely with the echo representation of fibrosis, calcification, and lipid material. In addition,in vitro studies of balloon angioplasty demonstrate that intravascular ultrasound accurately represents the changes in the structure of artery segments following balloon dilatation.     

不稳定斑块血管内超声特征的实验研究

目的　明确不稳定斑块的血管内超声 (IVUS)影像学特点。方法　 2 7只雄性新西兰纯种兔随机分成A组 (17只 )与B组 (10只 ) ,A组用球囊损伤腹主动脉 高脂喂养 10周 ,B组仅给予高脂喂养 10周。于 8周末将A组在腹主动脉斑块形成处转染携带人野生型 p5 3基因的重组腺病毒载体 ,于 10周末 ,两组实验兔分别给予中国斑点蝰蛇毒和组胺药物触发斑块破裂。应用IVUS分别测量、比较斑块破裂前的腹主动脉同一血管段中多个病变部位及其参考部位的IVUS指标 ,明确不稳定斑块的IVUS影像学特点。结果　破裂与未破裂斑块的参考部位的血管外弹力膜面积 (EEMA)、管腔面积、斑块面积及管腔面积狭窄率相比 ,差异无显著性意义 (P >0 .0 5 )。与未破裂斑块相比较 ,破裂斑块具有较大的偏心性 (P <0 .0 0 1) ,EEMA、斑块面积及管腔面积狭窄率明显大于前者 ,差异有显著性意义 (均P <0 .0 0 1)。破裂斑块呈现明显的正性重构 ,而稳定斑块主要表现为负性重构。结论　IVUS应用于已建立的动脉粥样硬化不稳定斑块动物模型上 ,能够准确地识别动脉粥样硬化不稳定斑块 ,本研究为临床早期发现不稳定斑块并预测斑块破裂奠定了实验基础。     

血管内超声对冠状动脉粥样硬化斑块及其狭窄的研究

目的：应用血管内超声（IVUS）检测冠状动脉,探讨其不同性质斑块的超声特征及血管的代偿性重构能力。方法：应用IVUS检测71例患者89处冠状动脉血管段总截面的最大径和最小径、管腔最大径和最小径、总截面面积及管腔面积。算出斑块的面积狭窄率和直径狭窄率,然后将所测值进行统计学分析。结果：①血管总截面随斑块面积的增加而增加,少量斑块组（面积狭窄率＜40％）的增加比例最大,其斑块面积每增加1mm^2,血管总截面积就增加1.99mm^2;硬斑块组增加比例最低,斑块面积每增加1mm^2,血管总截面积才增加0.58mm^2;大量斑块组（面积狭窄率≥40％）的斑块面积每增加1mm^2,血管总截面积增加1.06mm^2;②血管腔面积号斑块面积无相关（硬斑块组除外,它呈弱负相关）;③血管总截面积与血管腔面积呈正相关（硬斑块组除外）;④直径狭窄率与面积狭窄率呈明显正相关。结论：①病变血管的代偿性重构能力与斑块的狭窄程度及性质有关,它以轻度病变为最高,硬斑块为最低,重度病变并未完全消失;②病变血管腔的大小与斑块的性质关系较大,而与珏块的形态关系不大;③可用直径狭窄率代替面积狭窄率判断血管的狭窄程度,使检测更方便快捷。     

Does remodeling occur in the diseased human saphenous vein bypass grafts? An intravascular ultrasound study

Background: Coronary artery remodeling is a common phenomenon in human atherosclerotic arteries. Controversies exist concerning the presence of absence of the remodeling process in diseased human coronary saphenous vein bypass grafts. The purpose of the study was to observe the vessel and lumen dimensions in patients who had undergone saphenous vein grafting with intravascular ultrasound to find out whether the remodeling process exists in the diseased human saphenous vein bypass grafts. Methods: A total of 43 saphenous vein bypass grafts from 43 patients (39 males, 4 females, mean age 63 ± 8 years); 1–16 years (mean 9.3 ± 4.0 years) after grafting, who had not undergone previous catheter intervention, were studied using intravascular ultrasound. The vessel, lumen and plaque area were measured at the lesion segment as well as in the proximal and distal reference segments. The percent stenosis was calculated. Results: In 43 bypass grafts having severe stenosis before intervention, plaque was eccentric in 69.4% and concentric in 30.6%. No calcification was detected in 75% cases and 25% cases has mild-moderate intimal calcification. The vessel area in the lesion segment was 19.0 ± 9.7 mm², significantly larger than the proximal reference segment 12.8 ± 4.0 mm² as well as the distal reference segment 12.9 ± 3.6 mm² (p < 0.001). It was also larger than that of the average area of the proximal and distal reference segments (p < 0.001). The vessel area increased in accordance with plaque area (p < 0.001). A weak relationship existed between vessel area and percent stenosis (r = 0.37, p = 0.04). Conclusion: In contrary to previous findings, diseased human saphenous vein bypass grafts undergo focal compensatory enlargement (remodeling) in the presence of plaque formation. The underlying mechanism is probably similar to that in de novo atherosclerosis.