胎儿心脏周长及面积Z-评分在预测胎儿重型α-地中海贫血中的研究

Study of Z-score of fetal heart circumference and heart area in prediction of homozygous α-thalassemia

目的探讨中孕期胎儿心脏周长(HC)Z-评分、面积(HA)Z-评分在预测重型α-地中海贫血中的价值。方法对2014年2月至2019年3月广西壮族自治区妇幼保健院233例孕15~23周具有重型α-地中海贫血风险的胎儿进行超声心动图检查,测量胎儿心脏HC、HA及心胸比(CTR),并将前两者换算成Z-评分。绘制三者ROC曲线进行分析,对比心脏HC Z-评分、HA Z-评分、CTR预测胎儿重型α-地中海贫血的效能,最后通过最佳截断值获取其敏感性、特异性、阳性预测值及阴性预测值。结果①患病组为确诊重型α-地中海贫血胎儿65例,对照组为轻型及正常胎儿168例。②与对照组比较,患病组胎儿心脏HC Z-评分、HA Z-评分及CTR明显增高,两组间差异有统计学意义(均P<0.001)。③HA Z-评分ROC曲线下面积最大,且预测效能最高(与HC Z-评分、CTR比较的Z值分别为2.144、2.517,P<0.05)。④以HC Z-评分>1.67、HA Z-评分>2.06、CTR>0.53为最佳截断值,对预测15~23周重型α-地中海贫血胎儿的敏感性分别为92.31%、100%、89.23%,特异性分别为94.05%、95.83%、93.45%,阳性预测值分别为84.43%、89.00%、84.05%,阴性预测值分别为96.91%、100%、95.57%。结论胎儿心脏HC Z-评分及HA Z-评分是安全、有效预测重型α-地中海贫血的超声新指标,尤其HA Z-评分预测效能明显高于传统CTR,可在产前提高重型α-地中海贫血胎儿的检出率,减少侵入性检查。

Objective To explore the values of Z-scores of fetal heart circumference(HC)and heart area(HA)in prediction of homozygousα-thalassemia.Methods From February 2014 to March 2019,233 fetuses of 15 to 23 gestation weeks with risk of homozygousα-thalassemia were examined by prenatal ultrasound in the Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region.HC,HA and cardiothoracic ratio(CTR)were measured.HC and HA were converted into Z-scores,respectively.The ROC curves were established and analyzed based on HC Z-score,HA Z-score or CTR respectively to compare their predicting efficacies for fetal homozygousα-thalassemia.Finally,the sensitivity,specificity,positive predictive value and negative predictive value were obtained by the best cutoff values.Results①Sixty-five fetuses were diagnosed as homozygousα-thalassemia and classified asα-thalassemia group.One hundred and sixty-eight fetuses were mild and normal and were classified as control group.②HC Z-score,HA Z-score and CTR in theα-thalassemia group were significantly higher than those in the control group,and the differences between the two groups were statistically significant(P<0.001).③The area under ROC curve of HA Z-score was the largest compared with HC Z-score and CTR,and the prediction efficacy was the highest(Z test=2.144 and 2.517 respectively,P<0.05).④The best cutoff values were HC Z-score>1.67,HA Z-score>2.06 and CTR>0.53.Sensitivities of predicting homozygousα-thalassemia in 15 to 23 gestation weeks were 92.31%,100%and 89.23%,respectively.Specificities were 94.05%,95.83%and 93.45%,respectively.Positive predictive values were 84.43%,89.00%and 84.05%,respectively.Negative predictive values were 96.91%,100%and 95.57%,respectively.Conclusions Fetal heart HC Z-score and HA Z-score are safe and effective novel ultrasonic indexes for predicting homozygousα-thalassemia.Especially compared with traditional CTR,HA Z-score has a significantly higher predicting efficacy,which can improve the detection rate of homozygousα-thalassemia and reduce the need for invasive examination.