经胸超声心动图评价扩张型心肌病患者升主动脉弹性.doc

经胸超声心动图评价扩张型心肌病患者升主动脉弹性 作者：陈旭栩林丽珊叶夏敏邱浩强 【关键词】 超声摘要:目的:应用超声心动图评价扩张型心肌病患者升主动脉弹性及年龄、血压对升主动脉弹性的影响。方法：我们对19例扩张型心肌病患者和18例正常对照者进行超声心动图检查。升主动脉弹性用Ep和表示。结果：扩张型心肌病患者升主动脉Ep(1.310.69 N/m2106)和(18.718.74)显著高于正常人(0.300.12 N/m2106，P <0.001；4.621.65，P <0.001)。扩张型心肌病组和正常组中男女性之间升主动脉弹性无显著差异。正常组中，年龄分别与Ep(r=0.66, P=0.003)和(r=0.65, P=0.003)分别相关，收缩压仅与Ep(r=0.63, P=0.005)相关；扩张型心肌病组中，年龄与Ep(r=0.72, P=0.001)和(r = 0.71, P =0.001)分别相关，收缩压仅与Ep(r=0.56, P=0.01)相关。结论：扩张型心肌病患者升主动脉弹性减低。年龄、收缩压为影响升主动脉弹性的重要因素。关键词:心肌病；充血性；升主动脉弹性；超声心动图描记术Echocardiographic Study of Ascending Aortic Distensibility in Patients With Idiopathic Dilated CardiomyopathyAbstract： Objective: To assess the ascending aortic distensibility in patients with idiopathic dilated cardiomyopathy and the effects of aging and blood pressure on ascending aortic distensibility by transthoracic echocardiography. Method: 19 patients with idiopathic dilated cardiomyopathy and 18 healthy subjects underwent assessment of the ascending aortic distensibility by echocardiography. Ascending aortic distensibility was shown by aortic pressure-strain elastic modulus(Ep) and stiffness index beta(). Results: Ep(1.310.69 N/m2106) and (18.718.74) were significantly higher in patients with idiopahtic dilated cardiomyopathy than in healthy subjects(0.300.12 N/ m2106, P <0.001; 4.621.65, P <0.001 respectively). There were no differences in distensibility between men and women in either patients with idiopathic dilated cardiomyopathy or healthy subjects. Among healthy subjects, age was positively correlated with Ep(r=0.66, P=0.003) and (r=0.65, P=0.003) respectively and systolic blood pressure was only positively correlated with Ep(r=0.63, P=0.005). Among patients with idiopahtic dilated cardiomyopathy, age was positively correlated with Ep(r=0.72, P=0.001) and (r=0.71, P=0.001) respectively and systolic blood pressure was only positively correlated with Ep(r=0.56, P=0.01). Conclusions: This study demonstrated that decreased ascending aortic distensibility exists in patients with idiopathic dilated cardiomyopathy. Aging and systolic blood pressure are important factors affecting the ascending aortic distensibility.Key words：Cardiomyopathy；Congestive; Ascending aortic distensibility; Echocardiography 主动脉在心血管系统功能中起重要作用。大动脉结构和功能的改变是早期动脉粥样硬化的标志之一，可以导致高血压，也可影响心脏结构和功能的改变1。目前尚未见对扩张型心肌病引起的充血性心力衰竭的升主动脉弹性的报道。本研究应用经胸超声心动图评价扩张型心肌病患者升主动脉弹性，并评价年龄、血压与升主动脉弹性之间的关系。1 材料与方法1.1 一般资料：扩张型心肌病组19例，男15例，女4例，年龄范围1068岁，平均年龄4215岁。纽约心脏病学会心功能不全分级级，有心力衰竭病史6个月以上，除外冠状动脉疾病、高血压病、高脂血症、糖尿病及肾功能不全患者。试验前1224h禁用心血管活性药物如钙拮抗剂、血管紧张素转换酶抑制剂、血管紧张素拮抗剂等。健康对照组18例，其中男12例，女6例，年龄范围1565岁，平均年龄3714岁。1.2 方法：使用西门子Acuson Sequoia 512 型彩色多普勒超声显像系统, 探头频率2MHz4MHz。所有受检者处于左侧卧位。显示标准左室长轴切面，调整探头方向，显示升主动脉长轴切面。以二维超声作引导，将M型超声心动图取样线置于主动脉瓣上约3cm处，取样线尽量与升主动脉长轴垂直，清晰显示主动脉前壁内膜连续线形回声至少5个心动周期。同步连接心电图。所有记录贮存在磁光盘上，随后脱机分析处理。分别于心电图T波和R波相对应处测量升主动脉收缩期(Ds)和舒张期内径(Dd)。同时，用袖带血压计测量肱动脉收缩期(Ps)和舒张期血压(Pd)，取3次测量的平均值。升主动脉弹性用Ep和表示：Ep计算为Dd(Ps-Pd)/(Ds-Dd)1333；计算为DdLn(Ps/Pd)/(Ds-Dd)。1.3 统计学分析：所有计量资料表示为均数标准差，非配对t检验进行组间比较。变量之间的关系用单元线形相关分析。P0.05定为有统计学意义。2 结果扩张型心肌病组和健康对照组两组间年龄、性别、体重、身高相匹配。左室射血分数扩张型心肌病组显著低于健康对照组(P0.0010，左室舒张末期内径扩张型心肌病组显著高于健康对照组(P0.001)见表1。扩张型心肌病组与对照组升主动脉弹性指标：两组间收缩压、舒张压、脉压差、收缩期内径差异无显著性。舒张期内径扩张型心肌病组显著大于正常组(P=0.01)，收缩期与舒张期内径之差正常组显著高于扩张型心肌病组（P 0.001）。扩张型心肌病组升主动脉弹性显著低于正常组，表现为Ep和显著高于正常组(P <0.001)，见表2。表1 扩张型心肌病组和对照组的一般特征(略)表2 扩张型心肌病组和对照组升主动脉弹性指标(略)两组中男女间Ep和值无显著性差异，见表3。表3 扩张型心肌病组和对照组男女间升主动脉弹性指标(略)3 讨论主动脉弹性下降是心血管系统老化的标志2。主动脉和中等大小动脉如颈总动脉的粥样硬化改变与心血管疾病发病率密切相关3，并且这些动脉的早期动脉粥样硬化改变最终可导致收缩期高血压、心脏肥大，甚至心力衰竭4。目前，对于高血压病的主动脉弹性研究较多1,4。以往有作者曾用经胸超声心动图评价血管紧张素拮抗剂对高血压病患者升主动脉弹性的影响，证明经胸超声心动图测量升主动脉内径观察者及观察者间变异很小5。本研究我们用经胸超声心动图研究扩张型心肌病患者升主动脉弹性，发现Ep及显著高于正常人，表明升主动脉弹性减低。我们还发现男女间Ep和值无显著性差异，说明性别不是升主动脉弹性的影响因素。Pearson等6研究发现随年龄、血压升高，胸主动脉弹性减低。我们也发现年龄、收缩压与Ep及正相关，表明年龄和收缩压是升主动脉弹性的重要影响因素。肾素-血管紧张素-醛固酮系统改变可能是导致扩张型心肌病患者升主动脉弹性降低的原因之一。血管紧张素可以诱导动脉壁内平滑肌细胞增生和胶原沉积7，使动脉弹性降低。离体研究证实去甲肾上腺素和血管紧张素可以降低动脉弹性1，在体研究也证实将去甲肾上腺素和血管紧张素注入动物及人体内都可降低动脉弹性8，9。Lage等10发现扩张型心肌病患者去甲肾上腺素、肾素和醛固酮水平异常升高，并且这些神经激素水平与动脉弹性减低有关。升主动脉壁营养障碍对扩张型心肌病升主动脉弹性的损害作用不可排除。升主动脉外壁的营养来自冠状动脉的供血11。有证据表明扩张型心肌病患者冠状动脉内皮依赖性血管舒张功能是减低的，冠脉血管紧张性升高可能会影响主动脉壁的营养，引起主动脉壁结构成分的改变，如脂质沉积、平滑肌细胞增生、胶原纤维增多等，导致升主动脉弹性下降。参考文献：1Dzau VJ, Safar ME. 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