中国医科大学学报  2021, Vol. 50 Issue (4): 345-350

文章信息

王东, 王彧, 张颖
WANG Dong, WANG Yu, ZHANG Ying
超声多参数对妊娠期糖尿病患者中孕期胎儿心脏功能的评估价值
Prognostic value of ultrasound parameters for evaluating the effect of gestational diabetes mellitus on fetal cardiac function in the second trimester of pregnancy
中国医科大学学报, 2021, 50(4): 345-350
Journal of China Medical University, 2021, 50(4): 345-350

文章历史

收稿日期:2020-11-25
网络出版时间:2021-04-07 14:35
超声多参数对妊娠期糖尿病患者中孕期胎儿心脏功能的评估价值
王东 , 王彧 , 张颖     
中国医科大学附属盛京医院超声科, 沈阳 110004
摘要目的 探讨超声多参数对妊娠期糖尿病(GDM)患者中孕期胎儿心脏功能的评估价值。方法 选择2020年4月至2020年10月中国医科大学附属盛京医院诊断为GDM的中孕期孕妇62例作为GDM组,选择同期进行胎儿心脏超声检查的健康中孕期孕妇30例作为对照组。所有孕妇自愿参加本研究并签署了知情同意书。所有孕妇均进行空腹血糖、口服葡萄糖耐量测试,GDM组孕妇测量糖化血红蛋白值。采用GE公司的Voluson E10超声诊断仪进行胎儿整体评估,并使用多参数评价胎儿心脏功能变化。结果 2组胎儿整体超声评估均未发现明显畸形,2组胎儿胎龄比较无统计学差异(P > 0.05)。与对照组比较,GDM组胎儿左、右心室的等容收缩时间(IVCT)、等容舒张时间(IVRT)、心肌性能指数(MPI)增大(均P < 0.05)。而二尖瓣舒张早期血流速度,二尖瓣舒张晚期血流速度,二尖瓣舒张早、晚期流速比值,三尖瓣舒张早期血流速度,三尖瓣舒张晚期血流速度,三尖瓣舒张早、晚期流速比值,左心室射血时间2组比较无统计学差异(均P > 0.05)。GDM组胎儿左心室IVCT、右心室IVCT、MPI均与胎龄正相关(均P < 0.05)。结论 与正常孕妇胎儿比较,GDM孕妇胎儿心室IVCT、IVRT、MPI增大,提示GDM胎儿心脏功能可能受损。组织多普勒超声下测量的IVCT、IVRT、MPI指标能够便捷快速评估胎儿心脏功能的改变。
关键词妊娠期糖尿病    胎儿心脏    心脏功能    心肌性能指数    组织多普勒    
Prognostic value of ultrasound parameters for evaluating the effect of gestational diabetes mellitus on fetal cardiac function in the second trimester of pregnancy
Department of Ultrasound, Shengjing Hospital of China Medical University, Shenyang 110004, China
Abstract: Objective This study aimed to evaluate the effects of gestational diabetes mellitus (GDM) on fetal cardiac function in the second trimester of pregnancy using multiple ultrasonic parameters. Methods A total of 62 women with GDM (the GDM group) and 30 healthy pregnant women (the control group) were included in this study. All study subjects were recruited from April 2020 to October 2020 from the Department of Ultrasound, Shengjing Hospital of China Medical University, Shenyang, China. Written informed consent was obtained from the patients for publication of clinical details, clinical images, and videos. Fasting blood glucose measurements and oral glucose tolerance tests were performed in all pregnant women, and glycosylated hemoglobin was measured in pregnant women with GDM. Obstetrical ultrasound was performed using the GE Voluson E10 Ultrasound System, and multiple parameters were used to evaluate the changes in fetal cardiac function. Results No abnormalities were found in the fetuses of both groups during the overall evaluation. Compared with the control group, the isovolumic contraction time (IVCT), isovolumic relaxation time (IVRT), and myocardial performance index (MPI) of the GDM group were higher (P < 0.05). There were no statistically significant differences between the two groups in mitral E, mitral A, mitral E/A, tricuspid E, tricuspid A, tricuspid E/A, and left ventricular ejection time (P > 0.05). In addition, the IVCT and MPI of the left ventricle were both positively correlated with the estimated gestational age (all P < 0.05). Conclusion Fetuses of mothers with GDM presented signs of cardiac dysfunction. The IVCT, IVRT, and MPI of fetuses in the GDM groups were higher than those of fetuses in the normal group. Moreover, IVCT, IVRT, and MPI measured by Doppler tissue imaging can easily and quickly assess fetal cardiac morphology and function.

妊娠糖尿病可以分为妊娠期糖尿病(gestational diabetes mellitus,GDM) 和糖尿病合并妊娠。GDM是怀孕期间首次出现的碳水化合物不耐受而引起的糖尿病[1]。2019年国际糖尿病联盟数据显示,全球妊娠糖尿病患病率为15.8%,其中GDM占81%[2]

孕妇在中孕期皮质醇、孕酮、催乳素、生长激素、胎盘泌乳素等激素分泌增加,导致胰岛素受体信号转导通路受阻,孕妇对胰岛素敏感性显著降低。当这种生理性胰岛素抵抗加重时便可能发展为GDM。研究[3]表明,过多葡萄糖可改变细胞脂质代谢,影响孕妇子宫动脉的通畅性;同时也会产生大量活性氧,引起氧化应激反应,增加胎儿畸形的风险;高血糖还会导致胎儿高胰岛素血症,使胎儿血氧水平降低,胎儿缺氧会伴随肾上腺素儿茶酚胺激增,继而引起胎儿心脏结构重塑与心肌肥大,影响胎儿心脏的功能[4]。GDM损伤胎儿心脏的机制尚不完全清楚。近些年,超声多采用心肌性能指数(myocardial performance index,MPI) 联合房室瓣血流频谱等参数[5-6]来评估胎儿心脏功能改变。本研究探讨超声多参数对GDM患者中孕期胎儿心脏功能的评估价值。

1 材料与方法 1.1 研究对象及分组

本研究为单中心前瞻性队列研究。选择2020年4月至2020年10月中国医科大学附属盛京医院诊断为GDM的孕妇62例作为GDM组,校正孕周为24+0~27+6周,选择同期盛京医院进行胎儿心脏超声检查的健康孕妇30例作为对照组,校正孕周为24+0~27+6周。所有孕妇均自愿参加本研究并签署知情同意书。

入组标准: (1) GDM组患者均符合国际糖尿病与妊娠研究协会提出的GDM诊断标准[7];(2) 18周岁以上;(3) 单胎妊娠;(4) 无精神疾病,可配合检查。排除标准: (1) 怀孕期间吸烟者;(2) 双胎或者多胎妊娠;(3) 伴有慢性高血压、高血脂、甲状腺疾病,妊娠前患有糖尿病等;(4) 染色体异常胎儿;(5) 胎儿存在各个系统畸形;(6) 胎儿心率 < 120次/min或 > 160次/min;(7) 超声图像显示不佳;(8) 孕妇拒绝参加本项研究。

1.2 研究方法

1.2.1 一般临床资料收集

测量孕妇身高,记录孕前体质量,计算体质量指数(body mass index,BMI)。记录2组孕妇年龄、末次月经时间、孕周、空腹血糖以及GDM组糖化血红蛋白(glycosylated hemoglobin,HbA1c)水平。

1.2.2 胎儿整体超声评估

采用GE Voluson E10超声诊断仪,配有C2-9-D探头(探头频率2~9 MHz),常规评估胎儿有无畸形。记录胎儿心率,测量胎儿双顶径、头围、腹围、股骨长,使用机器内置的算法Hadlock标准推算出估测胎龄(estimated gestational age,EGA) [8]

1.2.3 心血管参数测量

根据美国超声心动图学会指南[9],测量二尖瓣和三尖瓣舒张早期(E波)、舒张晚期(A波) 的血流速度及其相应的比值(E/A)。使用组织多普勒(Doppler tissue imaging,DTI) 测量左心室和右心室的等容收缩时间(isovolumic contraction time,IVCT)、等容舒张时间(isovolumic relaxation time,IVRT)、射血时间(ejection time,ET) 和MPI。MPI也称Tei指数,Tei= (IVCT+IVRT) /ET。同时测量2组孕妇双侧子宫动脉(uterine artery,UtA)、胎儿脐动脉(umbilical artery,UA)、大脑中动脉(middle cerebral artery,MCA)、主动脉峡部(aortic isthmus,AoI)、静脉导管(ductus venosus,DV) 和肺静脉(pulmonary vein,PV) 的阻力指数(resistance index,RI) 和搏动指数(pulsatility index,PI),见图 1

图 1 右心室组织多普勒MPI的测量 Fig.1 The measurement of right ventricle MPI using Doppler tissue imaging

1.3 统计学分析

采用SPSS 22.0统计学软件进行分析。对计量资料进行正态分布性检验,符合正态分布的连续型计量资料以x±s表示,组间比较采用独立样本t检验。使用Pearson相关分析孕妇年龄、EGA、BMI、HbA1c与胎儿心脏功能指标之间的相关性,P < 0.05为差异有统计学意义。

2 结果 2.1 2组一般临床指标及整体超声评估结果比较(表 1)
表 1 2组一般临床特征的比较 Tab.1 Comparison of clinical characteristics between the two groups
Item GDM group (n = 62) Control group (n = 30) P
Maternal age (year) 31.86±3.60 31.83±2.94 0.977
BMI (kg/m2) 25.48±4.38 22.53±3.96 0.002
FHR (beat/min) 146.30±7.47 144.85±6.26 0.333
EGA (week) 26.24±1.35 26.15±1.58 0.522
Gestational age (week) 26.01±1.16 25.84±1.09 0.786
BMI,body mass index;FHR,fetal heart rate;EGA,estimated gestational age.

结果显示,2组孕妇年龄、EGA以及胎儿心率未见明显差异(均P > 0.05),而GDM组孕妇孕前BMI明显高于对照组(P < 0.05)。GDM组孕妇平均HbA1c为(5.39±0.56) mmol/L。整体超声评估结果显示,2组胎儿均未见明显系统畸形,2组胎儿EGA与孕妇末次月经测得孕周基本相符,2组胎儿EGA比较差异没有统计学意义(P > 0.05)。

2.2 2组胎儿主要血管血流频谱特征比较

结果显示,2组孕妇双侧UtA以及胎儿的UA、MCA、DV、PV的RI与PI未见明显差异(均P > 0.05);而GDM组胎儿AoI的PI较对照组减小(P < 0.05),见表 2

表 2 2组胎儿血流动力学评估结果 Tab.2 Comparison of fetal hemodynamics between the GDM group and control group
Item GDM group (n = 62) Control group (n = 30) P
L-UtA      
  Resistance index 0.52±0.13 0.53±0.09 0.821
  Pulsatility index 0.89±0.45 0.86±0.21 0.785
R-UtA      
  Resistance index 0.51±0.11 0.56±0.13 0.180
  Pulsatility index 0.86±0.35 1.04±0.64 0.091
UA      
  Resistance index 0.66±0.07 0.68±0.05 0.328
  Pulsatility index 1.07±0.19 1.08±0.13 0.744
MCA      
  Resistance index 0.82±0.05 0.82±0.07 0.812
  Pulsatility index 1.88±0.35 1.90±0.36 0.817
AoI      
  Resistance index 0.85±0.04 0.87±0.04 0.077
  Pulsatility index 2.18±0.26 2.33±0.36 0.038
DV      
  Resistance index 0.48±0.17 0.48±0.20 0.994
  Pulsatility index 0.65±0.35 0.64±0.38 0.943
PV      
  Resistance index 0.53±0.10 0.56±0.08 0.123
  Pulsatility index 0.74±0.18 0.80±0.19 0.185
L-UtA,left uterine artery;R-UtA,right uterine artery;UA,umbilical artery;MCA,middle cerebral artery;AoI,aortic isthmus;DV,ductus venosus;PV,pulmonary vein.

2.3 2组胎儿心脏功能参数比较

结果显示,2组胎儿二尖瓣和三尖瓣舒张早期(E波)、舒张晚期(A波)的血流速度及其相应的比值(E/A),左心室ET未见明显差异(均P > 0.05)。与对照组比较,GDM组胎儿的左心室IVCT、IVRT、MPI,右心室IVCT、IVRT、MPI显著增大(均P < 0.05);而右心室ET显著减小(P < 0.05),见表 3

表 3 GDM组与对照组心功能指标比较 Tab.3 Comparison of cardiac function between the GDM group and control group
Item GDM group Control group P
Mitral E (m/s) 0.34±0.08 0.34±0.08 0.937
Mitral A (m/s) 0.58±0.12 0.58±0.14 0.952
Mitral E/A ratio 0.58±0.10 0.59±0.09 0.704
Tricuspid E (m/s) 0.40±0.09 0.41±0.13 0.599
Tricuspid A (m/s) 0.60±0.10 0.64±0.19 0.194
Tricuspid E/A ratio 0.67±0.16 0.64±0.08 0.448
LV-IVCT (ms) 47.31±8.12 38.83±6.03 < 0.001
LV-IVRT (ms) 46.03±7.77 40.90±7.31 0.004
LV-ET (ms) 172.61±15.04 178.52±12.13 0.069
LV-MPI 0.55±0.10 0.45±0.07 < 0.001
RV-IVCT (ms) 51.69±10.41 42.76±9.29 < 0.001
RV-IVRT (ms) 47.55±9.86 40.45±6.46 0.001
RV-ET (ms) 170.02±11.52 178.21±11.57 0.002
RV-MPI 0.59±0.09 0.47±0.07 < 0.001
mitral E,mitral early diastolic flow velocity;mitral A,mitral late diastolic flow velocity;tricuspid E,tricuspid early diastolic flow velocity;tricuspid A,tricuspid late diastolic flow velocity;LV,left ventricle;IVCT,isovolumic contraction time;IVRT,isovolumic relaxation time;ET,ejection time;MPI,myocardial performance index;RV,right ventricle.

2.4 GDM组胎儿心脏功能指标与孕妇年龄、BMI、HbA1c及EGA的相关分析

结果显示,GDM组胎儿左心室IVCT、右心室IVCT、MPI与孕妇EGA呈正相关(均P < 0.05),见表 4

表 4 GDM组胎儿主要心功能指标的相关分析 Tab.4 Correlation analysis of main cardiac function parameters in the GDM group
Item Maternal age BMI EGA HbA1c
LV-IVCT        
r -0.039 0.035 0.260 0.334
P 0.768 0.794 0.047 0.162
LV-IVRT        
r 0.074 0.086 0.166 0.044
P 0.576 0.515 0.209 0.860
LV-MPI        
r 0.031 0.126 0.270 0.280
P 0.815 0.343 0.039 0.246
RV-IVCT        
r -0.074 -0.170 0.323 -0.115
P 0.568 0.186 0.010 0.621
RV-IVRT        
r 0.085 -0.082 0.005 0.094
P 0.511 0.524 0.971 0.685
RV-MPI        
r -0.060 -0.132 0.207 0.134
P 0.642 0.305 0.106 0.564
AoI-PI        
r -0.147 -0.037 -0.065 -0.200
P 0.275 0.786 0.632 0.441
BMI,body mass index;EGA,estimated gestational age;HbA1c,glycosylated hemoglobin;LV,left ventricle;IVCT,isovolumic contraction time;IVRT,isovolumic relaxation time;MPI,myocardial performance index;RV,right ventricle;AoI,aortic isthmus;PI,pulsatility index.

3 讨论

本研究利用超声多参数来评估GDM患者胎儿心脏功能的改变。结果显示,2组胎儿二尖瓣、三尖瓣血流频谱无统计学差异,与之前研究[10]结果相似。二尖瓣、三尖瓣舒张期血流模式通常为“单向双相”,由舒张早期心室舒张主导的E波和舒张晚期心房收缩主导的A波构成,通常胎儿时期E/A < 1,有研究提示E/A值随着孕周增长而变大,提示心室舒张功能随着孕周的增长逐渐完善[10]。也有研究[11]报道妊娠期糖尿病胎儿二尖瓣E/A较正常组减小。造成这些结果差异的原因可能与胎儿孕周有关。由于胎儿血流动力学的复杂性、胎儿呼吸运动、胎动等因素,且房室瓣流速对前、后负荷高度敏感,因此房室瓣舒张期血流比值不能很好地衡量心脏功能的改变,而且,由于胎儿心率过快,存在E、A波难以区分的情况。

IVCT、IVRT等均可用来反映心脏功能。IVCT代表心脏刚开始收缩的时期,对应的是房室瓣的关闭与对应的半月瓣开放之间的间隙,IVCT越长,代表收缩力越差。IVRT代表心脏刚开始舒张的阶段,对应的是半月瓣关闭与对应的房室瓣打开之间的时间。心室顺应性或舒张功能受损时可能会延长IVRT[12]。本研究发现GDM组IVCT、IVRT较对照组延长,提示GDM组胎儿左、右心室收缩、舒张功能均可能减低,与之前研究[11]结果相似。

PV、DV是与心房相连的静脉,心房压力变化可能影响它们的血流状态。左心房收缩及左心室舒张导致左心房内压力变化,这是引起PV血流的直接动力。而DV的流速直接决定血液通过卵圆孔的流量。有研究[13]显示GDM胎儿PV-PI高于正常胎儿,伴有心肌肥厚GDM胎儿的DV-PI较没有心肌肥厚或正常胎儿明显增高[14]。本研究PV、DV在2组中未存在统计学差异,这可能是由于心室功能改变较小,还未影响到PV与DV。

AoI作为胎儿时期唯一真正的动脉分流,是收缩期左、右心室射血功能之间博弈和舒张期大脑与胎盘血流阻力之间博弈结果的反映。本研究结果发现,GDM胎儿AoI-PI明显低于正常胎儿,这可能是GDM影响心室舒张功能,导致左心房压力增高,流经卵圆孔的血流阻力增大,从而使得右心室输出量增加,即使在舒张期肺动脉瓣关闭之后,也会影响通过峡部的顺行血流,从而使得AoI-PI降低[15]

MPI (Tei指数) 最先由日本学者[16]提出,常用于评价心脏的整体功能。最初的测量方法分为两步,在心室流入道和流出道两个位置的两个波形中分步测量等容时间与ET。然而胎儿心脏复杂多变,分步测量等容时间与ET存在较大误差。2005年,改良MPI研究[17]提出在左心室流出道切面的单个多普勒波形中可同时测量左心室的等容时间和ET,并计算出左心室MPI,从此避免了不同多普勒波形中心率差异等带来的误差。然而右心室解剖结构与左心室不同,右心室流入道与流出道难以在一个切面显示,而且,对于胎儿来说右心系统更加重要,因此有学者[18]使用DTI来测量右心室的MPI,发现与频谱多普勒比较,使用DTI可以更加灵敏反映出GDM胎儿异常的右心室MPI。本研究使用DTI测量IVCT、IVRT、MPI等指标,结果显示GDM组胎儿MPI较对照组增大,而且MPI增大主要是IVCT及IVRT增大导致的,这可能与GDM引起心脏收缩及舒张功能减低有关。本研究还发现GDM组胎儿左心室MPI与EGA存在正相关,这表明随着EGA的增加,GDM胎儿左心室的整体功能在随之减低,同时发现GDM胎儿左心室IVCT也随EGA增加而增加,提示GDM胎儿整体功能的减低多与收缩功能受损有关,与之前学者[19]研究相似。GDM组中的这种变化可能与高血糖对胎儿心脏影响的时间累积有关,相关的机制仍需要进一步研究。本研究同时发现HbA1c水平与IVCT、IVRT、MPI等参数的相关性较差,有关血糖水平与心脏功能改变的机制研究仍不明确,另外本研究中GDM孕妇血糖控制均较好,因此是否需要早期更严格临床干预有待进一步研究。

综上所述,GDM可能导致中孕期胎儿心脏功能受损,产前超声多参数可以来评估心脏功能的改变。ICVT、ICRT以及MPI是评估胎儿心脏功能改变的敏感指标。

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