Prenatal diagnosis of isolated total anomalous systemic venous return to the coronary sinus (2009)

A woman was referred for fetal echocardiography at 21 + 3 weeks' gestation on suspicion of mitral valve (MV) atresia with left ventricular (LV) hypoplasia and an ostium primum atrial septal defect (ASD). No associated extracardiac or chromosomal anomalies were identified. The fetus had dextrocardia, and no classic four-chamber view could be obtained; there seemed to be a large ostium primum ASD, no patent MV and a relatively small LV (Figure 1a). However, more anteriorly, a smallish patent MV (Figure 1b and c) was visualized as well as the left atrium receiving the pulmonary veins (Figure 1d). On the three-vessel view1, no right superior vena cava (SVC) was seen. The innominate vein drained into a persistent left SVC (Figure 2a), which itself drained into a very dilated (9.6 mm; normal, 1.6 mm2) coronary sinus (CS) (Figure 2b). The ductus venosus and the hepatic veins joined the distal part of the inferior vena cava as normal. The inferior vena cava also drained into the dilated CS just before its opening into the right atrium (Figure 2b). The great vessels originated in normal positions but were slightly discordant, with an aorta/pulmonary artery (Ao/PA) diameter ratio of 0.92 (50th centile3). The dilated CS was found in fact to have displaced the MV anteriorly, causing LV inflow impairment, with the mouth of the CS having been misdiagnosed as an ostium primum ASD. The echocardiographic features remained stable throughout pregnancy except for the Ao/PA ratio, which decreased to 0.69 by week 32 + 6 (< 5th centile3). A coarctation of the aorta (CoAo) was suspected. The remainder of the pregnancy was uneventful. Ultrasound images of the fetal heart: an abnormal four-chamber view (a), which led to suspicion of a large ostium primum atrial septal defect (*) and atretic mitral valve (MV) (arrow) with a relatively hypoplastic left ventricle (LV). In a more anterior and oblique view (long-axis view), a patent MV is visualized (arrow) (b) with normal color Doppler flow pattern (c). Posterior to the MV, a very dilated coronary sinus (CS) can be seen. In a slightly more anterior/superior plane than the classic four-chamber view, pulmonary veins can be seen to be draining to the true left atrium (arrows) (d). The mouth of the CS opening into the right atrium (*) gives the false impression of a large ostium primum atrial septal defect. AO, ascending aorta; LA, left atrium; RV, right ventricle. (a) Ultrasound image of the fetal heart in cranial axial view, in which a large left superior vena cava (LSVC) can be visualized on the left of the pulmonary artery (PA). Ascending aorta (AO)/PA size disproportion is also apparent. (b) Sagittal view showing the LSVC and the hepatic veins (HV) draining into a large coronary sinus (CS) into which the inferior vena cava (not shown on the picture) also drained. (c) Schematic diagram showing the total anomalous systemic venous return to the CS. DV, ductus venosus; INN V, innominate vein; IVC, inferior vena cava; LA, left atrium; LV, left ventricle; PV, pulmonary vein; RA, right atrium; RV, right ventricle; UV, umbilical vein. *Mouth of the CS opening into the RA. A male infant was delivered vaginally at full term. Clinical examination was normal. Dextrocardia and total anomalous systemic venous return (TASVR) towards the CS (Figure 2c) were confirmed, but CoAo was not observed on echocardiography. Abdominal ultrasonography showed a normal single spleen and a normally positioned liver. At the time of writing the infant was 20 months of age and showed normal development. Congenital anomalies of the systemic venous drainage represent a heterogeneous group of malformations4. Some of them have been described prenatally, in particular persistent left SVC5, 6. Abnormal systemic venous drainage may be isolated or associated with complex heart diseases, mainly heterotaxy syndromes; we did not find any evidence of such an associated syndrome. The physiological consequences of these anomalies vary in severity from minor and clinically insignificant to a right-to-left shunt with systemic arterial desaturation needing surgical repair. The literature on TASVR, especially to the CS, is very limited. In 1997 Kadletz et al.7 reported an infant with TASVR to the CS associated with an ostium primum defect and a CoAo. The infant underwent surgical repair of the associated anomalies without complications. The presence of a dilated CS may give rise to uncertainties over cardiac anatomy and, as in this case, suspicion of mitral atresia. A dilated CS may also be misdiagnosed as an ostium primum ASD and abnormal pulmonary venous connection has to be ruled out. CoAo is associated, to a certain degree, with the presence of a dilated CS8, 9 but its prenatal diagnosis remains challenging10, and CoAo was not confirmed in this case. All of these possible diagnoses have a different prognosis, therefore an exact differentiation in the prenatal period is warranted. In summary, we have presented the first fetal diagnosis of a case of isolated TASVR to the CS and have highlighted the need for a precise antenatal diagnosis to guide both perinatal management and parental counseling. C. Barrea* , J.-M. Biard , G. Hutchings , P. Bernard , * Pediatric Cardiology Unit, Department of Pediatrics, University Clinic Saint Luc, UCL, 10 Av. Hippocrate, 1200 Brussels, Belgium, Fetal Medicine Unit, Department of Obstetrics & Gynecology, University Clinic Saint Luc, UCL, 10 Av. Hippocrate, 1200 Brussels, Belgium