山﨑 麻子¹, 土井 茂治², 川滝 元良³

Asako YAMAZAKI¹, Shigeharu DOI², Motoyoshi KAWATAKI³

¹順天堂大学大学院医療看護学研究科, ²稲毛バースクリニック, ³神奈川県立こども医療センター新生児科

¹Graduate School of Health Care and Nursing, Juntendo Graduate School, ²Inage Birth Clinic, ³Pediatric Department, Kanagawa Children's Medical Center

キーワード : fetal echocardiography, AVSD, dilated coronary sinus, TAPVD

総肺静脈還流異常（Total anomalous pulmonary venous drainage: TAPVD）は胎児診断が最も難しい先天異常のひとつであるが，病型によっては出生後すぐに手術をすることが児の予後に大きく関わることが知られており，胎児診断が非常に重要である．今回，胎児スクリーニングで冠状静脈洞拡大をきっかけにTAPVD type Ⅱa型の診断に至った症例を経験したので，その診断へのプロセスを報告する．25歳女性，1妊0産．妊娠20週の妊娠中期スクリーニングにてmidlineに一部欠損を認め，房室弁の高さは同一レベルに見えたことから，部分房室中隔欠損症（partial AVSD）を疑った．その他四腔断面（Four Chamber View: 4CV），三血管断面（Three Vessel View: 3VV），三血管気管断面（Three Vessel Trachea View: 3VTV），大動脈弓（Aortic arch）は正常像，左右1本ずつの肺静脈が左心房に流入していると判断した．初回の検査では欠損孔血流方向が不明瞭であり，児の成長を待って再度検査を施行することとした．26週の超音波にて，欠損孔を通過する血流方向が左‐右であることから，partial AVSDは否定的であり，midlineの欠損は拡大した冠状静脈洞であることが判明した．冠状静脈洞拡大をきたす疾患として最も多い左上大静脈遺残（Persistent Left Superior Vena Cava: PLSVC）は認めなかった．また，左右の肺静脈が接近して拡大した冠状静脈洞に還流していることが判明した．以上から，TAPVD type Ⅱaと診断し，高次医療施設へ紹介とした．Midlineの欠損をきっかけに当初partial AVSDと診断したが，血流方向の左右方向であること，PLSVCを認めないことなどから，TAPVDのtype Ⅱaと診断した1例を経験したので報告する．

Total anomalous pulmonary drainage (TAPVD) is a congenital anomaly that is extremely difficult to diagnose in the prenatal phase. However, it is essential that TAPVD is diagnosed during the prenatal period as some types of TAPVD require surgery soon after birth; moreover prompt treatment can affect the neonatal prognosis. In this article, we report our experience of prenatal diagnosis of isolated TAPVD type IIa with a dilated coronary sinus at 2^nd trimester fetal ultrasound screening, along with a brief review of the literature. The patient was a 25-year-old primigravida without any medical or family history. At 20 weeks of gestation, 2^nd trimester fetal ultrasound screening was performed. A partial atrioventricular septal defect (AVSD) was suspected. A partial midline defect in the heart was suspected, and the level of the atrioventricular valve appeared to be at nearly the same position in both ventricles. The images of other cardiac features were normal; when looking at the pulmonary vein for the first time, a connection to the left atrium (LA) was observed, at least in each of the right and left pulmonary venous connections. At 20 weeks of gestation, it was difficult to judge the direction of the blood flow. Thus, we decided to check it again after the fetus had grown. At 26 weeks of gestation, we found that the blood flow direction was from left to right, which is an unusual direction. The suspicion of partial AVSD was then rejected. The “septal defect" on the ultrasound image was actually a dilated coronary sinus. No features of persistent left superior vena cava (PLSVC), which is the most common anomaly when there is a dilated coronary sinus., were seen. Additionally, the pulmonary vein merged into the dilated coronary sinus. Based on these findings, we concluded that this was a case of isolated TAPVD type IIa. Therefore, we referred the patient to a tertiary hospital. In this case, a midline defect initially raised the suspicion of partial AVSD. After careful observation, however, we detected an unusual direction of the blood flow, and the resulting rejection of PLSVC led to a diagnosis of type IIa TAPVD.