冠脉内超声、电子束CT及冠脉造影检测冠脉粥样硬化病变的对比研究

1、    冠脉内超声、电子束CT及冠脉造影检测冠脉粥样硬化病变的对比研究         摘要：目的比较和评价冠脉内超声(ICUS)、电子束CT(EBCT)及冠脉造影(CAG)检测冠脉粥样硬化病变的价值。方法10例患者同时行ICUS、EBCT和CAG检查。对所成像的10支靶血管共35个血管段,逐个血管段比较分析其检测冠脉粥样病变的结果。结果CAG正常的19个血管段中,9段(47.4%)ICUS显示粥样斑块,斑块负荷(33.0±14.0)%(14.5%52.2%),6段

2、(31.6%)EBCT存在钙化;与ICUS相比,CAG和EBCT诊断冠脉所有病变总的敏感性均为64.0%,特异性分别为100%和90.0%,准确性分别为74.3%和71.4%(P=0.763);EBCT诊断钙化斑块和脂质纤维斑块的敏感性、特异性、阳性预测值、阴性预测值、准确性分别为92.3%,77.3%,70.6%,94.4%,82.9%和33.3%,43.5%,23.5%,55.6%,40.0%。结论对CAG正常血管,ICUS和EBCT均有助于发现冠脉早期病变或被CAG低估的病变;以ICUS作为判断冠脉粥样病变的“金标准”,EBCT和CAG对冠脉粥样斑块的诊断效率相近;EBCT对钙化病变的检

3、出率较高,对少部分脂质纤维斑块仍可检出有钙盐沉积。关键词：超声检查,介入性;体层摄影术,X线计算机;冠状血管造影术;冠状动脉硬化A comparative study of EBCT,ICUS and CAG for detection of coronary atherosclerosisZHU Jun,SHI Haiming,LUO Xinping,et al.(Department of Cardiology,Huashan Hospital,Shanghai Medical University,Shanghai 200040,China)Abstract：ObjectiveTo an

4、alyze and compare the preliminary results of electron beam computed tomography(EBCT) with those of intracoronary ultrasound (ICUS) and coronary angiography (CAG) for in vivo detection of coronary atherosclerotic plaques.MethodsTen patients (seven males and three females) with an average age of (65&#

5、177;7) years were included in the study.On a site by site basis,35 coronary segments in ten target vessels were analyzed with EBCT,CAG and ICUS.ResultsAtherosclerotic plaque was found by ICUS in nine(47.4%) of 19 segments with normal angiogram,and the plaque burden measured by ICUS was (33.0±14

6、.0)% (14.5%52.2%),coronary calcium deposits were detected by EBCT in 6 (31.6%) segments of angiographically normal segments.Compared with CAG,EBCT yielded a sensitivity of 68.8% and a specificity of 68.4%.Compared with ICUS,an overall sensitivity of EBCT and CAG for detection of the atherosclerosis

7、was both 64.0%,the specificity was 90.0% and 100% and the accuracy was 74.3% and 71.4%,respectively(P=0.763).For plaques with and without ultrasound signs of calcifications,the sensitivity of EBCT was 92.3% and 33.3%,the specificity was 77.3% and 43.5%,the positive predictive value was 70.6% and 23.

8、5%,the negative predictive value was 94.4% and 55.6%,and the accuracy was 82.9% and 40%.ConclusionsEBCT and ICUS imaging may be helpful to identify the atherosclerotic plaques in angiographically normal artery or underestimated lesions.As compared with ICUS,there was no significant difference for th

9、e detection of coronary atherosclerosis between CAG and EBCT.EBCT detects calcified plaques with higher sensitivity and about one-third of soft/fibrous plaques also can be detected.Key words：Ultrasonography,interventional;Tomography,X-ray computed;Coronary angiography;Coronary arteriosclerosis研究表明,冠

10、脉内超声(ICUS)对冠脉粥样硬化病变,尤其对斑块早期阶段的检测比冠脉造影(CAG)更具优势,目前已有学者提出ICUS是诊断冠脉粥样病变的新的“金标准”1。然而,CAG和ICUS均属创伤性诊断方法,均有一定的操作并发症,患者依从性较差。而无创性电子束CT(EBCT)检查,由于能够准确识别和定量冠脉钙化(CAC)而被用来判断粥样病变及诊断冠心病。本研究运用上述三种诊断方法对检测冠脉粥样病变作一初步对比评价,报告如下。资料与方法一、研究对象自1997年12月至1998年4月间,对我科10例冠脉介入患者进行了靶血管的ICUS检查。男7例,女3例,年龄5475岁,平均(65±7)岁,中位数年

11、龄64岁。其中稳定性心绞痛3例,不稳定心绞痛4例,急性心肌梗死1例,胸痛原因待查2例。合并高血压7例,高胆固醇血症4例,糖尿病2例,吸烟5例。二、研究方法1.首先以Judkin's法完成CAG,术后即刻ICUS检查。使用CIVS INSIGH 血管内超声显像仪,机械旋转式超声导管(探头频率 30 MHz,外径2.9F)。显像方法参见文献2。所得像经录像脱机回放分析。2.在ICUS显像前后2周内行EBCT检查。采用Imatron公司C-150型扫描成像系统,自气管分叉下相当于主肺动脉平面起,层厚 3 mm,连续扫描2030层至心尖部包括整个心脏。扫描时要求被检者屏气。三、像分析处理1.冠

12、脉血管分段:根据冠脉解剖标志并参照文献3,4,把冠脉分成左主干及左前降支、左回旋支、右冠脉各近、中、远三段共10个血管段。2.若每血管段上EBCT钙化积分值1判为EBCT(+);积分为0则EBCT(-)。CAG血管无任何狭窄或斑块,管腔光滑弹性良好者为CAG(-);管壁僵硬不规则,管腔狭窄10%或管腔异常扩张者判为CAG(+)。如果ICUS显示冠脉正常三层结构或仅有内膜增厚者为正常血管段,ICUS(-);斑块负荷10%为斑块血管段,ICUS(+)。对斑块血管段再进一步分为脂质纤维斑块和钙化斑块(包括混合斑块)(1)。每血管段均分析最显著病变处的像。    

13、;3.CAC定量积分按Agatston's法5计算。四、数据分析及统计学处理诊断试验的评价采用敏感性、特异性、阳性预测值(PPV)、阴性预测值(NPV)和准确度;配对计数资料采用McNemar's检验。P<0.05为有显著性差异。结果所有患者均顺利进行了CAG和ICUS检查。成像的10支靶血管中,左前降支6例,右冠脉4例。共检查了36个血管段,包括左主干6处,左前降支18处,右冠脉12处(其中1处右冠远端血管段超声像不清晰而剔除)。一、与CAG相比,ICUS及EBCT检测冠脉粥样硬化病变的结果CAG正常的19个血管段中,10段ICUS亦正常,另9例则存在粥样斑块,占47.

14、4%,斑块负荷达(33.0±14.0)%(14.5%52.2%),而EBCT发现6处钙化(+),占31.6%;CAG异常的16个血管段中,ICUS均示有粥样斑块的存在(100%),EBCT也发现11处钙化(+),占68.8%,另5处积分为0,这5处冠脉狭窄程度(66.0±34.0)%,其中有4处ICUS显示为脂质纤维斑块。二、与ICUS相比较,EBCT检测冠脉粥样硬化病变的结果(2)<"t143-1 (7760 bytes)" src="/med/cano/201003/20100323171630607" 74 476>

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17、7078 bytes)" src="/med/cano/201003/20100323171631935" 75 476><"t143-9 (10280 bytes)" src="/med/cano/201003/20100323171631882" 92 476>A、B 分别为左冠脉前降支近段和中段处的ICUS像,显示冠脉钙化C、D 为同一患者EBCT的左前降支影像,分别显示其近段、中段两处存在钙化病灶2示 ICUS、EBCT、CAG检测冠脉粥样斑块病变在35个血管段中,ICUS显示正常血管10段(28.

18、2%),脂质纤维斑块血管12段(34.3%),钙化斑块血管13段(37.1%)。在13处钙化斑块血管段中,有12处EBCT钙化(+),占92.3%;22处超声未显示钙化斑块的血管段中,EBCT仍发现5处钙化阳性(22.7%)。12处脂质纤维斑块中,4处EBCT钙化积分(+),占1/3。10处正常血管段中,ICUS未发现斑块,但有1处EBCT钙化积分为2分。三、检测冠脉粥样硬化病变诊断方法的评价见表1。表1与ICUS比较EBCT和CAG对冠脉粥样硬化的检出结果(%)检查方法检测对象敏感度特异性阳性预测值阴性预测值准确度EBCT钙化斑块92.377.370.694.482.9脂质纤维斑块33.34

19、3.523.555.640.0任何斑块*64.090.094.150.071.4CAG冠脉斑块64.0100.0100.052.674.3     注:*McNeman检验,2=0.091,P=0.763讨论本研究首次在国内应用ICUS、EBCT和CAG对冠脉粥样硬化病变的检测结果进行了初步比较和评价。一、CAG与ICUS对检出冠脉粥样硬化病变的比较本研究CAG与ICUS的对比研究发现,在CAG正常血管段中,ICUS发现近一半的血管段存在粥样斑块,斑块负荷(斑块面积狭窄百分比)已达(33.0±14.0)%(14.5%52.2%),表明CAG并不

20、利于发现早期的粥样斑块和实际病变的严重程度,与国外报道结果相似6-8。其原因可能与动脉粥样硬化早期阶段发生的适应性冠脉重构有关,即Glagovs现象9。而CAG异常的所有血管段中,ICUS则均能发现明显的粥样斑块,也进一步说明ICUS能更准确地识别早期的冠脉病变。因此,对临床高度怀疑冠心病但CAG正常的患者,进一步ICUS检查有助于早期或被CAG低估病变的发现,可作为一种与CAG互为补充的新的诊断工具。与ICUS相比,CAG诊断粥样斑块的敏感性64.0%,NPV 52.6%,特异性却达100%,表明在诊断冠脉粥样硬化病变上,仍具有一定的价值。二、EBCT与ICUS检测冠脉粥样硬化病变的比较研究

21、表明,EBCT对钙化病变的识别具有很高的敏感性、特异性10。本组病例中,EBCT诊断钙化斑块的敏感性92.3%,NPV 94.4%,准确性82.9%,与国外文献报道的97.0%,99.0%,82.0%结果相仿3。但有一处钙化斑块,其积分为0,考虑可能系成像中患者屏气不佳,心脏扫描层面移位漏检所致。在22段ICUS无钙化征象的血管中,也发现5处EBCT钙化积分达(5.6±12.2)分,但明显低于钙化斑块的(99.0±94.0)分(P<0.05)。其中33.3%的脂质纤维斑块EBCT存在钙化,低于国外报道的47.0%3。在ICUS正常血管段中,有1处(10.0%)钙化2分

22、,推测可能由于ICUS缺乏检测动脉外膜稀疏呈放射状分散的钙盐,而EBCT则是检测整个部位钙盐的沉积量。研究表明,ICUS检测钙化病变主要依赖于钙化分布的组织学形式。在粥样斑块成熟过程中,斑块内可发生微钙化(Microcalcification),由于超声是根据钙化后方声影诊断的,而声影的产生需斑块内含有相当的钙盐量。ICUS在检测致密钙化斑块时,敏感性可达90.0%,但对微钙化的检出率仅为64.0%77.0%11,12。因此EBCT对检测钙盐在血管上的沉积较ICUS敏感。但从临床实用角度来看,由于EBCT不能显示斑块性质,而ICUS却能准确了解靶病变的斑块构成和分布,因此,在指导冠脉介入治疗时

23、,ICUS应比EBCT更佳。鉴于术前准确识别严重钙化病变在指导冠脉介入性治疗中具有非常重要的意义,因此,我们认为在有条件的单位,冠脉介入术前EBCT检查了解血管钙化程度,结合术中ICUS评价斑块性质,将有助于降低手术并发症,提高成功率。三、如果均以ICUS作为判断粥样病变的“金标准”,EBCT和CAG诊断斑块的敏感性均为64.0%,特异性分别为90.0%和100%,P=0.763,说明两种方法诊断粥样病变的效率一致。只是两者提供了冠脉粥样病变不同方面的信息。CAG反映了血管狭窄的严重性;而EBCT则是对斑块本身特性的检测。本组CAG异常的16段中,有5段积分为0。这5处ICUS发现4处(80.

24、0%)是脂质纤维斑块,提示EBCT并不能准确判断冠脉狭窄的程度。而CAG正常的19例中,有6段(31.6%)钙化阳性,ICUS均有粥样斑块存在,提示冠脉可能发生重构所致。晚近研究13也发现,在CAG正常或近乎正常血管中,EBCT仍能检测出表现为 “点状”(spotty)钙化病变,认为EBCT能检测出表现为早期冠脉重构的病变,似乎比CAG更具有优势。由此看来,通过EBCT钙化的检测,可以发现一些造影正常的血管病变,有利于冠脉轻微病变的检出。综上,对CAG正常血管,ICUS和EBCT均有助于发现冠脉早期病变或被CAG低估的病变;若以ICUS作为判断粥样病变的“金标准”,EBCT和CAG对冠脉粥样硬

25、化病变的诊断效率相仿,另外,EBCT对钙化病变的检出率较高,近1/3的脂质纤维斑块也有钙盐沉积。作者单位：朱军(上海医科大学附属华山医院心内科200040)施海明(上海医科大学附属华山医院心内科200040)罗心平(上海医科大学附属华山医院心内科200040)王受益(上海医科大学附属华山医院心内科200040)范维琥(上海医科大学附属华山医院心内科200040)戴瑞鸿(上海医科大学附属华山医院心内科200040)参考文献：1Waller BF,Pinkerton CA,Slack JD,et al.Intravascular ultrasound:a histologic study of v

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