血管内超声、64层螺旋CT及定量冠状动脉造影对不稳定性心绞痛患者冠状动脉病变的评价

目的 应用血管内超声(rvos)探讨不稳定性心绞痛(UAP)低、中及高危组患者动脉粥样硬化斑块的特点,评价定量冠状动脉造影(QCA)和64层螺旋CT(MDCT)的诊断价值.方法 采用IVUS、MDCT和QCA分析61例UAP患者(低危组17例,中危组33例,高危组11例)71支病变血管.分析比较3组患者斑块的形态学特点.根据IVUS斑块回声的强度,将斑块分为软斑块、纤维斑块、钙化斑块、混合斑块,计算最小面积处斑块负荷,并分为≤50%、51%～74%及≥75%3类病变.以IVUS结果为标准,评价QCA计算血管狭窄程度的可信性,MDCT诊断3类病变的敏感性和特异性,及对斑块成分诊断的可靠性.结果 QCA可估计低危组和中危组患者的斑块负荷(低危组r=0.768,P<0.01;中危组r=0.721,P<0.01).高危组患者血管重构明显(冠状动脉重构指数=1.21±0.31),QCA低估了IVUS的斑块负荷[分别为(67±14)%、(75±16)%,r=0.551,P<0.01].MDCT对冠状动脉病变有较高的阴性预测值(87.8%-96.3%),但无法区分典型粥样硬化斑块内的纤维帽(kappa=0.245)及脂质核(kappa=0.235).3组患者IVUS斑块特点分析结果表明,随着危险度程度的增加,软斑块比例、血管正性重构程度、血管外弹力膜面积、最小管腔面积、斑块负荷、斑块破裂及血栓发生率逐渐增加.结论 QCA可以相对准确地评价UAP低危和中危组患者的冠状动脉狭窄程度,同时会低估高危组患者的病变程度.MDCT对于冠心病的诊断有非常高的阴性预测值可用于排除冠心病,但是无法可靠地区分粥样硬化斑块内的纤维帽及脂质核.IVUS检查显示软斑块、正性血管重构和最小管腔面积<4mm~2者可能为UAP高危组患者.

Value of intravascular ultrasound, 64 multi-detector computed tomography and quantitative coronary angiography on lesion of coronary artery in unstable angina pectoris patient

Objective To compare the value of intravascular ultrasound (IVUS) and assess the value of quantitative coronary angiography ( QCA) and 64 multi-detector computed tomography ( MDCT) on unstable anginas (UAP) risk stratification. Method A total of 61 UAP patients (low risk; 17, middle risk; 33 and high risk; 11) were recruited, 71 vessels were examined by MDCT, QCA and IVUS. Plaque characteristics (soft, fibrous, calcified and mixed plaques) and plaque burden at minimum area ( ≤50% , 51%-74% and ≥75%) were detected, calculated and analyzed. Results derived from various detection methods were compared. Results Plaque burden detection by QCA was comparable to IVUS results for low and middle risk UAP ( r = 0. 768 and r = 0. 721, respectively; all P < 0. 01 ) but not for high risk UAP ( 67% ± 14% vs. 75% ± 16% , P < 0. 01) due to significant positive vessel remodeling ( remodeling index = 1.21±0.31). The high negative predict value of MDCT for stenosed coronary vessels(87. 8%-96. 3%) was valuable for exclusion of coronary heart disease but MDCT was not able to identify fibrous cap( kappa = 0. 235) and lipid core ( kappa = 0. 245 ) . Extent of remodeling index, external elastic membrane area, minimum lumen area, plaque burden, plaque rupture and thrombosis increased in proportion to increasing risks of UAP patients. Conclusions QCA is a suitable tool for assessing UAP patients with low and middle vessel stenosis but underestimated the stenosis degree in UAP patients with high vessel stenosis. MDCT is valuable for exclusion vessel disease but not useful for identifying soft and fibrous plaque. Soft plaque with positive remodeling index and minimum lumen area <4 mm~2 derived from IVUS could correctly identify UAP patients with high degree of vessel stenosis.