Analysis of missed diagnosis of fetal mitral valve diseases by prenatal ultrasound

Objective To summarize the pathology and ultrasonic characteristics of fetal mitral valve diseases and improve their prenatal diagnostic accuracy by ultrasound. Methods Ultrasonic data of fetuses with mitral valve diseases, diagnosed by autopsy from January 2011 to December 2017 in Fetal Heart Disease Maternal Fetal Medicine Research Important Laboratories were retrospectively analyzed. Their ultrasound features and causes of missed diagnosis were analyzed. Results ①The pathologic types included mitral atresia(22 cases, 59.5%), mitral valve dysplasia(13 cases, 35.1%) and mucoid degeneration[2 cases (1 case was diagnosed with Marfan syndrome with dilated aortic sinus and sinus of pulmonary trunk), 5.4%]. ②Fetal ultrasound could detect mitral atresia and mucoid degeneration of mitral valve. There were five cases of mitral valve dysplasia which were missed by ultrasound.And the accuracy rate of ultrasonic diagnosis was 86.5%(32/37). ③The missed subtypes of mitral valve dysplasia included mild-moderate mitral stenosis with coarctation of aorta (4 cases) and mitral valve dysplasia with functional aortic atresia(1 case). Conclusions Fetal mitral valve diseases involve a variety of anatomical abnormalities and the main types are mitral atresia and mitral valve dysplasia. Mucoid degeneration of mitral valve is rare and it may belong to Marfan syndrome when combined with dilated aortic sinus and sinus of pulmonary trunk. Fetal ultrasound can identify mitral atresia and mucoid degeneration of mitral valve, but it may miss the diagnosis of some subtypes of mitral valve dysplasia, such as mild-moderate mitral stenosis with aortic coarctation and mitral valve dysplasia with functional aortic atresia. Key words: Ultrasonography, prenatal; Mitral valve; Fetus