阻塞性睡眠呼吸暂停低通气综合征模型猪颈总动脉超声和多普勒流速曲线实验研究

Studies on ultrasonography and Doppler velocity tracing of common carotid artery in obstructive sleep apnea hypopnea syndrome in a porcine model

目的用彩色多普勒超声观察阻塞性睡眠呼吸暂停低通气综合征(OSAHS)模型猪颈总动脉结构和血流动力学变化。方法12只雄性小型猪随机分为模型组和对照组,每组6只。模型组猪在低压仓内喂养,对照组猪在仓外喂养。待模型组猪出现OSAHS症状时,应用彩色多普勒超声仪检测双侧颈总动脉二维超声和Doppler超声,随后做病理学检查,并与对照组比较。结果与对照组比较,模型组猪颈总动脉内径变细、内中膜(IMT)增厚(P<0.05),收缩期峰值流速(S)、阻力指数(RI)、S/D等均升高(P<0.01),但舒张期流速(D)与对照组比较无显著差异。病理检查可见中膜弹力纤维增生,胶原纤维束明显增加,有灶性分布的纤维素样物,平滑肌细胞形态不规则。结论动脉内径、IMT厚度和多普勒流速曲线在动脉血管组织结构发生变化时均有改变;低压环境下培养的OSAHS模型猪气道压力改变对动脉系统有一定危害。

Objective To investigate the morphologic changes and hemodynamic parameters of the common carotid artery in obstrucrive sleep apnea hypopnea syndrome （OSAHS） in a porcine model using ultrasound and color Doppler. Methods A total of 12 pigs were randomly divided into model group and control group （n=6 for each）. All pigs were fed under the same conditions with exception of th ose in the model group which were kept in a hypobaric chamber for experiments. The parameters of systolic velocity （S） and diastolic velocity （D）, resistant index （RD and S/D in Doppler as well as maximum IMT （intima-media thickness） with two-dimensional ultrasound were obtained in the carotid artery of all animals were determined, and the latter was confirmed by animal dissection when the symptoms of OS AHS appeared in the model group. Results The diameter of the lumen of the common carotid artery in model group （3. 18±0. 17） was smaller than that of control group （3. 47±0. 15, P〈0. 05）, and the IMT （0. 57±0. 05） was thicker than that of control group （0.42± 0. 08, P〈0. 05）. The S （0. 88±0. 13m/s）, RI （0. 81±0. 04）, S/D （5. 43±1. 13） of model group were significantly higher than those in control group （0. 56±0. 09, 0. 68 ± 0. 04, 3. 03 ± 0.54, P〈0. 01）, and there was no significant difference of D between control group （0. 18±0. 04m/s） and model group （0. 17±0. 06m/s）. The pathological changes in common carotid artery included relative increase in content of elastic fibers with obviously increased collagen fibers, and focal distribution of fibrinoid materials and smooth muscle cells with irregulor shape were found in intima-media. Conclusions The values of blood flow parameters of Doppler and IMT, and luminal diameter of common carotid artery changed together with occurrence of morphological changes in common carotid artery. The changes in airway pressure in pigs with OSAHS lived under hypobaric condition may produce damage to the common carotid artery.