DISCUSSION
APVS/IVS is a rare form of APVS associated with high perinatal mortality in fetuses. The high loss rate was related to pregnancy termination, fetal heart failure, respiratory disease, and chromosomal abnormalities[1,2]. The long-term following-up information was rarely analysed, whether with or without surgery[2-4]. Hence, the correct time for subsequent pulmonary valve surgery remains unknown[5]. To the best of our knowledge, this is the first case to describe a patient with APVS/IVS who survived up to 27 years old and underwent timely pulmonary valve implantation surgery. The unique sub-type of APV/IVS in this patient also prompts a surprisingly long-term survival.
Volume overload due to a ductus arteriosus (DA) is limited to the right ventricle (RV) when the interventricular septum is intact, as previously described. Additionally, severe regurgitant flow from the pulmonary valve might further impair RV development. Francesca Monacci and Silvia Favilliet et al. indicated that spontaneous/surgical closure of the DA and progressive fall of pulmonary vascular resistance played an important role in promoting pulmonary forward flow and improving systolic and diastolic RV functions[4-5]. The patient’s hemodynamic and clinical conditions may improve if the RV was dilated but with good contractility, and an immediate pulmonary valve surgery would not be necessary[4-5]. Thus, we hypothesize that the patient in our case may spontaneously close the DA and successfully obtained biventricular circulation in fetuses without an impaired tricuspid valve.
Long-term follow-up was rarely achieved in previous reports, although successfully born alive[1,4]. Our case demonstrated severe RV dysfunction could develop as he grew up, although symptoms were initially mild. The correct time of subsequent pulmonary valve surgery should be established in some patients to avoid the over-dilation of the right heart. We emphasize that a life-long follow-up would be necessary for those patients. And more studies were needed to determine the correct time for pulmonary valve surgery.