二维斑点追踪成像技术评价亚临床甲状腺功能减退症患者左心室功能及收缩同步性变化

Two-dimensional speckle tracking imaging in evaluating the changes of left ventricular function and systolic synchrony in patients with subclinical hypothyroidism

目的观察亚临床甲状腺功能减退症(subclinical hypothyroidism,SCH)患者采用左旋甲状腺素治疗前、后左心室功能及收缩同步性变化,探讨二维斑点追踪成像(two-dimensional speckle tracking imaging,2D-STI)技术对其的评价价值。方法SCH患者42例为SCH组,均应用左旋甲状腺素钠片治疗;体检健康者45例为对照组。对照组、SCH组治疗前及治疗3个月后均行常规超声心动图和2D-STI检查,记录常规超声参数,包括左室射血分数(left ventricular ejection fraction,LVEF)、二尖瓣舒张早期血流速度(mitral valve early diastolic blood flow velocity,E)、二尖瓣环室间隔侧舒张早期运动速度(early diastolic velocity of the septal mitral annulus,e'S)、二尖瓣环侧壁侧舒张早期运动速度(early diastolic velocity of the lateral mitral annulus,e'L),计算e'S与e'L平均值(mean value of e'S and e'L,e')、E/e';记录2D-STI参数,包括左心室整体纵向应变(global longitudinal strain,GLS)、17节段纵向应变达峰时间(time to peak longitudinal strain,TTPLS)、17节段长轴TTPLS标准差(TTPLS mechanical dispersion,TTPLS-MD)、左心室基底段TTPLS(basal segment of TTPLS,TTPLSbase)、左心室中间段TTPLS(middle segment of TTPLS,TTPLSmid)、左心室心尖段TTPLS(apical segment of TTPLS,TTPLSapex),经心动周期RR间期标准化后以TTPLS%、TTPLS-MD%、TTPLSbase%、TTPLSmid%、TTPLSapex%表示。比较对照组、SCH组治疗前、SCH组治疗后常规超声参数及2D-STI参数;采用Pearson相关法分析SCH患者治疗前血清促甲状腺激素水平与GLS、TTPLS%及TTPLS-MD%的相关性。结果SCH组治疗前及治疗后e'S[(6.8±0.4)、(7.2±0.4)cm/s]、e'L[(9.2±0.6)、(9.6±0.8)cm/s]、e'[(8.1±0.4)、(8.4±0.5)cm/s]均低于对照组[(7.5±0.5)、(9.8±0.6)、(8.7±0.4)cm/s](P<0.05),E/e'[9.2(8.6,10.3)、9.1(8.1,9.7)]、GLS[(-22.7±0.7)、(-23.1±0.6)%]、TTPLS%[(41.7±1.6)、(39.9±1.9)%]、TTPLS-MD%[(3.7±1.4)、(3.2±1.5)%]、TTPLSbase%[(41.5±3.8)、(39.6±3.4)%]、TTPLSmid%[(42.6±3.1)、(40.9±3.1)%]、TTPLSapex%[(41.2±3.8)、(39.4±3.7)%]均高于对照组[9.0(7.7,9.5)、(-23.5±0.6)%、(37.6±1.6)%、(2.5±1.3)%、(37.2±2.7)%、(38.0±2.5)%、(37.6±3.3)%](P<0.05);SCH组治疗后e'S、e'L、e'均高于治疗前(P<0.05),E/e'、GLS、TTPLS%、TTPLS-MD%、TTPLSbase%、TTPLSmid%、TTPLSapex%均低于治疗前(P<0.05)。SCH患者治疗前血清促甲状腺激素水平与GLS、TTPLS%、TTPLS-MD%均呈正相关(r=0.380,P=0.013;r=0.198,P=0.208;r=0.607,P<0.001)。结论2D-STI技术可早期发现SCH患者左心室舒张功能、收缩功能及收缩同步性障碍,应用左旋甲状腺素治疗可有效改善SCH患者左心室功能和收缩同步性。

Objective To observe the changes of left ventricular function and systolic synchrony before and after levothyroxine tablet treatment in patients with subclinical hypothyroidism(SCH),and to investigate the predicting value of two-dimensional speckle tracking imaging(2D-STI).Methods Forty-two patients with SCH were treated with levothyroxine sodium tablets(SCH group),and another 45healthy volunteers were as controls(control group).Conventional echocardiography and 2D-STI were performed before treatment and after 3-month treatment.The conventional echocardiography parameters were recorded including left ventricular ejection fraction(LVEF),mitral valve early diastolic blood flow velocity(E),early diastolic velocity of the septal mitral annulus(e'S),and early diastolic velocity of the lateral mitral annulus(e'L)to calculate the mean value of e'S and e'L(e')and E/e',and the 2D-STI parameters were recorded including the left ventricular global longitudinal strain(GLS),17-segmental time to peak longitudinal strain(TTPLS),17-segmental TTPLS mechanical dispersion(TTPLS-MD),basal segment of TTPLS(TTPLSbase),middle segment TTPLS(TTPLSmid),apical segment TTPLS(TTPLSapex),which were expressed as TTPLS%,TTPLS-MD%,TTPLSbase%,TTPLSmid%and TTPLSapex%after RR interval standardized.All the above parameters were compared among control group,SCH group before treatment,and SCH group after treatment.Pearson correlation method was used to analyze the correlations of serum thyroid stimulating hormone(TSH)level before treatment with GLS,TTPLS%and TTPLS-MD%in SCH patients.Results The e'S,e'L and e'were lower in SCH group before treatment[(6.8±0.4),[(9.2±0.6),(8.1±0.4)cm/s]and SCH group after treatment[(7.2±0.4),(9.6±0.8),(8.4±0.5)cm/s]than those in control group[(7.5±0.5),(9.8±0.6),(8.7±0.4)cm/s](P<0.05),and lower in SCH group before treatment than those in SCH group after treatment(P<0.05).The E/e',GLS,TTPLS%,TTPLS-MD%,TTPLSbase%,TTPLSmid%and TTPLSapex%were higher in SCH group before treatment[(9.2(8.6,10.3),(-22.7±0.7)%,(41.7±1.6)%,(3.7±1.4)%,(41.5±3.8)%,(42.6±3.1)%,(41.2±3.8)%]and SCH group after treatment[(9.1(8.1,9.7),(-23.1±0.6)%,(39.9±1.9)%,(3.2±1.5)%,(39.6±3.4)%,(40.9±3.1)%,(39.4±3.7)%]than those in control group[(9.0(7.7,9.5),(-23.5±0.6)%,(37.6±1.6)%,(2.5±1.3)%,(37.2±2.7)%,(38.0±2.5)%,(37.6±3.3)%](P<0.05),and were higher in SCH group before treatment than those in SCH group after treatment(P<0.05).The serum TSH levels before treatment were positively correlated with GLS,TTPLS%and TTPLS-MD%in SCH patients(r=0.380,P=0.013;r=0.198,P=0.208;r=0.607,P<0.001).Conclusion 2D-STI can detect left ventricular diastolic dysfunction,systolic dysfunction and systolic synchrony disorder in early stage,and levothyroxine sodium tablets can effectively improve left ventricular function and systolic synchrony.