Yan Ying Liu, Tan Kenny B L, Yeo George S H
Antenatal Diagnostic Centre, KK Women's & Children's Hospital, Singapore.
Ann Acad Med Singap. 2008 Nov;37(11):906-12.
To present the characteristics and spectrum of associated anomalies in right- and left-sided isomerism in our local population and to assess the possibility of using stomach-distance ratio (SDR) of less than 0.34 as a diagnostic tool to predict right atrial isomerism.
This was a retrospective study of fetuses in our department over a period of 8 years with postnatally confirmed prenatal diagnosis of atrial isomerism.
In 22 cases, atrial isomerism was confirmed by post-mortem or postnatal echocardiography. Eighteen (81.8%) fetuses had right isomerism. Their main abnormal ultrasound findings were pulmonary stenosis or atresia (n = 9), atrioventricular septal defect (n = 10), right-sided stomach (n = 9), transposition of great arteries (n = 6), dextrocardia (n = 8), single ventricle (n = 4), juxtaposition of inferior vena cava and descending aorta (n = 5), ventricular septal defect (n = 2), interrupted inferior vena cava with azygous drainage (n = 2) and double outlet right ventricle (n = 3). Four (18.2%) fetuses had left isomerism. Their abnormal ultrasound findings were dextrocardia (n = 3), right-sided stomach (n = 3), atrioventricular septal defect (n = 2), double outlet ventricle (n = 2), ventricular septal defect (n = 1), pulmonary stenosis (n = 2) and interrupted inferior vena cava with azygous drainage (n = 1). 66.7% (12/18) of cases with right isomerism had SDR of less than 0.34 compared to 0% (0/4) of the cases with left isomerism (P = 0.02).
Our study suggests an Asian predilection towards right isomerism compared to Western populations. We postulate that there may be racial differences in the expression of these 2 forms of isomerism. The ultrasound findings of complex heart disease and abnormal arrangement of great vessels in abdominal cavity, though important, are varied and non-specific evidence for either form of fetal atrial isomerism. There is a possibility of using the SDR <0.34 (representing stomach proximity to the fetal spine) as a possible diagnostic tool to predict right-sided atrial isomerism.
介绍我们当地人群中右侧和左侧异构综合征相关异常的特征和范围，并评估使用小于0.34的胃-距离比值（SDR）作为预测右房异构的诊断工具的可能性。
这是一项对我院8年间经产后确诊为产前心房异构的胎儿的回顾性研究。
22例中，经尸检或产后超声心动图确诊为心房异构。18例（81.8%）胎儿为右异构。其主要超声异常表现为肺动脉狭窄或闭锁（9例）、房室间隔缺损（10例）、胃位于右侧（9例）、大动脉转位（6例）、右位心（8例）、单心室（4例）、下腔静脉与降主动脉并列（5例）、室间隔缺损（2例）、下腔静脉中断伴奇静脉引流（2例）和右心室双出口（3例）。4例（18.2%）胎儿为左异构。其超声异常表现为右位心（3例）、胃位于右侧（3例）、房室间隔缺损（2例）、心室双出口（2例）、室间隔缺损（1例）、肺动脉狭窄（2例）和下腔静脉中断伴奇静脉引流（1例）。右异构病例中66.7%（12/18）的SDR小于0.34，而左异构病例中这一比例为0%（0/4）（P = 0.02）。
我们的研究表明，与西方人群相比，亚洲人更易患右异构。我们推测这两种异构形式的表达可能存在种族差异。复杂心脏病的超声表现以及腹腔内大血管的异常排列虽然重要，但对于任何一种胎儿心房异构形式来说都是多样且非特异性的证据。有可能将SDR<0.34（表示胃靠近胎儿脊柱）作为预测右房异构的一种可能的诊断工具。
