ABC | Volume 112, Nº5, May 2019

Guideline Brazilian Fetal Cardiology Guidelines – 2019 Arq Bras Cardiol. 2019; 112(5):600-648 Table 4.2 – Distribution of fetal heart diseases according to their classification Group Cardiac anomalies IA Left to right shunt heart diseases: ASD, VSD, AVSD, and Ao-P window Diseases with mild outflow tract obstructions: PS, AS, and CoA Complex congenital heart diseases without significant obstructions of systemic or pulmonary outflow tracts: TOF, complex TGA, DORV, univentricular hearts, and CTGA IB Isolated extrasystoles; mild, isolated TR IIA Heart diseases with critical obstruction of systemic or pulmonary outflow tracts: PAIVS, Critical PS, Critical AS, and HLHS Heart diseases that need interatrial shunt: HLHS and variations, TGA, and TA Heart diseases with severe valve insufficiencies: Ebstein’s anomaly and tricuspid valve dysplasia, pulmonary valve agenesis, severe primary or secondary MR, secondary TR, and truncal valve insufficiency IIB Cardiomyopathies and myocarditis, arrhythmias, obstructive tumors, extrinsic compressions, (CDH and CCAM), ductal constriction, restrictive foramen ovale, ductus venosous agenesis, AVMs, TTTS, and twin gestation with 1 acardiac fetus III Severe chromosomal disorders; multiple malformations, cardiac defects that are not correctable, very severe forms of Ebstein’s anomaly or tricuspid valve dysplasia with lungs hypoplasia, LV aneurysms, or diverticula associated with fetal hydrops Ao-P: aortic to pulmonary; AS: aortic stenosis; ASD: atrial septal defect; AVMs: arteriovenous malformations; AVSD: atrioventricular septal defect; CCAM: congenital cystic adenomatoid malformation; CDH: congenital diaphragmatic hernia; CoA: coarctation of the aorta; CTGA: corrected transposition of great arteries; DORV: double outlet right ventricle; HLHS: hypoplastic left heart syndrome; LV: left ventricle; MR: mitral regurgitation; PAIVS: pulmonary atresia and intact ventricular septum; PS: pulmonary stenosis; TA: tricuspid atresia; TGA: transposition of great arteries; TOF: tetralogy of Fallot; TR: tricuspid regurgitation; TTTS: twin-twin transfusion syndrome; VSD: ventricular septal defect. what to do when they face a fetus with CHD. Because of the fetal physiology characteristics, the majority of cardiac anomalies have a benign outcome in utero. However, at birth, they may become devastating, and require specific treatment immediately after the umbilical cord clamping. On the other hand, mild fetal cardiac abnormalities may be overvalued and lead unnecessary attitudes regarding gestation and delivery conduction, just because of the lack of knowledge of the real impact of the anomalies to the baby’s health after birth. Although prenatal diagnosis has been possible for more than 40 years, understanding the behavior of CHD during the pre- and postnatal periods has become clearer over the past last years, thanks to the diagnostic accuracy improvements and to the introduction of fetal therapy that lead to progressive understanding of their natural and modified history. For these reasons, in order to guide the need of delivery and/or treatment in specialized centers, cardiac anomalies were separated into several groups according to their perinatal outcome: with and without hemodynamic compromise, with and without in utero progression, and possible postnatal outcome (Tables 5.1 to 5.8). 6. Fetal Ductal Constriction: Treatment and Prevention Fetal circulation has specific characteristics, differing morphologically and functionally from extrauterine circulation. Anatomically, the ductus arteriosus is part of the right ventricular outflow tract, playing a essential role in directing blood flow to lower portions of the fetus. Basically, the ductus arteriosus carries 80–85% of right ventricular output to the descending aorta. 60 It’s histological structure is composed of a thick muscle layer, which increases with gestational age. Its constrictive mechanism is facilitated by the circumferential orientation of muscular fibers, especially those of the external layer. 61 Due to these histological characteristics, its patency is measured by multiple factors. Luminal abnormalities may cause severe fetal and neonatal complications, such as heart failure, hydrops, persistent neonatal pulmonary hypertension, and death. 62-64 Typically, maternal use of indomethacin and/or other anti-inflammatory medications interferes with the metabolism of prostaglandins (PG), causing ductal constriction. 65-67 Many causes of ductal constriction and neonatal pulmonary hypertension, however, are not related to the use of these substances and are classified as idiopathic. 68 A growing amount of evidence has recently shown that herbs, fruits, nuts, and a wide variety of substances commonly consumed as part of a daily diet affect the inflammatory cascade, culminating in reduced PG synthesis. 69,70 This anti-inflammatory action, especially of polyphenols, when ingested during the third trimester of gestation, influences the dynamics of the fetal ductus arteriosus. 71-78 617