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.