Cardiac pathology: Prenatal diagnosis, management and outcome

Abstract

Over the years there has been steadfast increase in the quantity of patients with a prenatally detected structural congenital heart disease. Despite efforts to achieve the contrary, some of these pregnancies will end in intra-uterine death. In these patients the sole advantage of the prenatal diagnosis is the facilitation of thorough parental counseling concerning future pregnancies; additionally it might help parents better to cope with the loss of their child. The primary goal of prenatal detection of cardiac defects, however, is the enabling of better care in the immediate postnatal period and the most convincing justification for the efforts taken, would be to demonstrate that prenatally diagnosed patients have a better chance on a good outcome as a result of early initiation of therapy. This thesis shows that prenatal diagnosis of heart disease, both morphological and functional, may influence management of pregnancy and outcome for affected fetuses. It is the most important positive effect of prenatal diagnosis that the sequence of planned delivery in a center, equipped to treat this type of patients, and the immediate installment of appropriate therapy can lead to an improved long-term outcome. Lactate levels reflecting the overall oxygen deficiency experienced seem to be a good indicator to measure this possible positive effect. Planned delivery and immediate therapy may keep lactate levels of affected fetuses below 6.1 mmol/l, providing a safe starting point for surgical intervention with better chances of a normal neurophysiological development. The two extreme sides of the spectrum of prenatally encountered congenital heart disease described in this thesis, the hypoplastic left heart syndrome and Ebstein’s malformation, indicate that in these cases morphology dominates outcome in a negative manner. This implies that even the best managed pregnancies, deliveries and immediate care of these patients do not assure a favourable long-term outcome. Finally data concerning the well-controlled diabetic pregnancies show that this maternal disease infringes on both the fetal cardiac anatomy and circulation. The higher incidence of congenital heart disease is predominantly located in the cono-truncal region. The circulatory changes encountered in the structurally normal heart occur later in gestation and suggest to be adaptive to ensure an increased cardiac output.