Comparative study on ultrasonic diagnosis and pathological anatomy of congenital absent semilunar valve in first trimester

Objective To investigate the echocardiographic characteristics, pathological anatomy and genetic abnormality of congenital absent semilunar valves in first trimester. Methods Eleven cases of congenital absent semilunar valve fetus diagnosed at 11-13+ 6 weeks of gestation in Guangxi Magernity & Child Healthcare Hospital from December 2014 to December 2018 were analyzed. The characteristics of echocardiography and the abnormal microanatomy of cardiac tissue after labor induction was compared. Results The crown-lump length of the 11 fetus was 46-74(62.0±9.2)mm, and nuchal translucency thickness(NT) was 2.4-10.4 (6.4±2.6)mm. The NT of 10 cases were greater than 3.0 mm. Color Doppler flow imaging revealed that biphasic bidirectional flow in the aortic arch and/or pulmonary artery at the 3VT view( "to-and-fro" ) in those 11 cases, and pansystolic turbulence and pandiastolic reflux spectrum were showed on spectral Doppler. Among them, there were 10 cases of " stealing type" , including 2 cases of isolate absent aortic valves, 3 cases of absent pulmonary valves and 5 cases of absent both aortic and pulmonary valves; and all the 10 cases had secondary ultrasonic manifestations of fetal heart failure. Chromosome analysis and detection of genes showed that 4 cases with Trisomy 13 syndrome, 3 cases with Trisomy 18 syndrome, 1 case with 22q11.2 deletion, 1 case with 12q24.32q24.33 deletion and 1 case was normal. Pathological anatomy revealed enlarged heart in 8 cases, isolate absent aortic valves in 2 cases (1 case complicated with pulmonary atresia, absence of ductus arteriosus and thymus), absent pulmonary valves in 3 cases, absent both aortic and pulmonary valves in 3 cases, relics of semilunar valves in 3 cases. And 2 cases of absent pulmonary valves and 3 cases of absent both aortic and pulmonary valves with short and thick ductus arteriosus. Only 1 case was congenital absent semilunar valve in " non-stealing type" without secondary ultrasonic manifestations of fetal heart failure. Chromosome analysis and detection of genes showed 22q11.2 deletion, and there were relics of semilunar valves in the pathological anatomy. It also combined with tetralogy of Fallot and absence of ductus arteriosus. Conclusions In first trimester, congenital absent semilunar valves are more common as " stealing type" . The echocardiographic features of congenital absent semilunar valves are the " in-out sign" of aorta arch and/or pulmonary artery and biphasic spectrum in spectral Doppler. Trisomy 13 syndrome and trisomy 18 syndrome significantly increased the risk of congenital absent semilunar valves in " stealing type" in first trimester. Key words: Echocardiography; Congenital absentsemilunar valve; First trimester; Pathologic diagnosis