12 Tricuspid Atresia
12. The aortic arch is leftward and the ductal arch is slightly bigger than the aortic arch. The flow is reversed in the ductal arch (aorta to pulmonary) but is normal antegrade through the aortic arch.
Fig. 12-1 A, Fetal tricuspid atresia at 28 weeks’ gestation with no evidence of a tricuspid valve. The left ventricle (LV) is large. RA, right atrium B, Color Doppler of the right ventricle (RV) to pulmonary artery (PA) pulmonary stenosis with normally related great arteries. IVC, inferior vena cava; RA, right atrium. See also color version of figure in color insert.
a. Prostaglandin E1 (PGE1) infusion should be started to maintain ductal patency. The hyperoxia test could be deferred given the retrograde flow through the ductus arteriosus in utero consistent with critical pulmonary outflow obstruction.
b. Rarely, if the baby has relatively high systemic saturations but very poor perfusion and evolving evidence of right heart failure and poor cardiac output, an urgent balloon atrial septostomy is required to allow more mixing at the atrial level while surgery is arranged. At times, if the foramen ovale is mildly restrictive before birth, increased pulmonary venous return and higher left atrial pressures after birth can hamper the obligate right-to-left shunt and lead to increasing central venous pressures.
4. Postnatal echocardiography confirmed the diagnosis of tricuspid atresia, hypoplastic right ventricle, and severe critical pulmonary stenosis with a large muscular VSD. There was a large atrial septal defect (ASD) and a patent ductus arteriosus with bidirectional shunting.
9. Because this neonate was born with tricuspid atresia and pulmonary stenosis, the prognosis is the best of all the types of single ventricle. With a left ventricular pumping chamber, the long-term ventricular function is optimal.
c. In Allan and Sharland’s (1992) fetal series, incidence is 4%. In this series, out of 84 fetuses with tricuspid atresia, 54 pregnancies were terminated, there were two intrauterine deaths and four infant deaths, and 22 babies survived.
b. The surgical options are a single ventricle repair with a bidirectional Glenn at 3 to 6 months (surgical mortality is about 2%-3%), followed by a Fontan operation at 2 years (surgical mortality is 2%-5%).