Diverse outcome following early prenatal diagnosis of pulmonary stenosis

To assess the natural history and outcome of fetal pulmonary stenosis (PS), particularly that detected at 14-17 weeks' gestation.

In this retrospective study we searched an electronic database of women from the general Israeli population attending a private ultrasound institute (Al-Kol ultrasound institute in Haifa) for routine complete early fetal ultrasound, including all fetal systems and a fetal echocardiogram, between 2004 and 2015. Ninety-seven percent of the women were at low risk of fetal malformations, and 3% had risk factors such as maternal Type-1 diabetes mellitus, exposure during pregnancy to teratogenic drugs, or anomalies in previous pregnancies or in other family members. At presentation at 14-17 weeks of gestation, color and pulsed Doppler imaging were performed across the four cardiac valves. We identified cases in which abnormal flow was detected, leading to suspicion of PS; in these cases, a follow-up examination was carried out at 17-19 weeks and then monthly until delivery or resolution of the finding, and postnatal echocardiography was performed at birth, 4-6 weeks thereafter, and yearly afterwards. Outcome data for suspicious cases, including postnatal diagnosis and general or specific symptoms, were collected by contacting the parents via email or telephone.

Among 24 185 early prenatal transvaginal ultrasound screening examinations, 23 cases of suspected PS were identified. They were classified into three groups, according to their ultrasound findings. In Group A (n = 8), the ultrasound screen was normal except for high flow velocity across the pulmonary valve. In six cases, this finding had resolved by 20-21 weeks of gestation and all were found to be normal at postnatal follow-up, one case underwent termination of pregnancy at 19 weeks and PS was confirmed at autopsy and one case was lost to follow-up. In Group B (n = 12), there was aliasing across the pulmonary valve. Two of these cases were normal postnatally and eight had mild-to-moderate PS; the remaining two cases developed hypoplastic right ventricle and pulmonary atresia at 19-20 weeks and the pregnancies were terminated. In Group C (n = 3) PS was associated with other anomalies; all three pregnancies were terminated. There were an additional six cases (Group D) not identified in early gestation, in which PS was late-onset. One had tricuspid regurgitation at the early screen, but was subsequently diagnosed with Ebstein's anomaly and pulmonary atresia, at 22 weeks, and was terminated. The other cases had completely normal early ultrasound screening examinations: one case had Ebstein's anomaly and PS was diagnosed at birth; four had isolated mild PS, of which one was diagnosed at 22 weeks' gestation and the other three were diagnosed postnatally, before 3 months of age. The sensitivity for detection of the ascertained cases of PS was 64% (11/17) and the specificity was > 99%.

There is a diverse spectrum of presentation of fetal PS in the early mid-trimester. A possible explanation for this could be different pathophysiological pathways. Further study is needed to explain the different prenatal sonographic presentations in an unselected population. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.