Two-dimensional and M-mode echocardiography of the fetal coronary sinus

Prenatal Ultrasound Markers of Isolated Total Anomalous Pulmonary Venous Return and a Sequential Approach to Reach Diagnosis

This article comprehensively reviews the literature concerning prenatal ultrasound findings of isolated total anomalous pulmonary venous return (TAPVR) and the application of specific sonographic markers to differentiate among the TAPVR types. These markers can be categorized as direct and indirect, based on either morphological features or hemodynamic changes in TAPVR. Indirect markers include the ventricular disproportion, an increased distance between the left atrium (LA) and the descending aorta, as well as the dilatation of superior vena cava or coronary sinus for supracardiac or cardiac TAPVR, along with abnormal pulmonary venous spectral Doppler patterns. Direct markers predominantly focus on the absence of a connection between the pulmonary veins and the LA. Some direct markers are specific to certain TAPVR types, such as the vertical vein. Diagnosing isolated TAPVR can pose challenges, but following a sequential approach can improve detection rates and outcomes. In cases with equivocal findings, additional follow-ups are recommended. The sequential approach described in the current article provides a step-wise methodology and sonographic markers for prenatal diagnosis of TAPVR, which can be utilized by fetal-maternal medicine specialists, obstetricians, and radiological technicians to ensure timely interventions.

Comparison of coronary sinus diameter Z-scores in normal fetuses and fetuses with persistent left superior vena cava (PLSVC)

To establish Z-score reference ranges for coronary sinus (CS) diameter in normal fetuses and explore the diagnostic value of CS Z-score in fetuses with persistent left superior vena cava (PLSVC). Study of 235 normal fetuses and 30 fetuses with PLSVC was involved. Noncardiac biometrical parameters included biparietal diameter (BPD), femoral length (FL), heart area (HA), gestation age (GA). The coronary sinus systolic and diastolic diameter (CSDs and CSDd ) were measured at the end of systole and diastole. CSDs and CSDd Z-score models were constructed by using linear regression analysis with Non-cardiac biometrical parameters as independent variables. Z-scores between normal fetuses and fetuses with PLSVC were compared. A simple, linear regression model was the best description and correlations between fetal CSDs and CSDd and four independent variables were excellent. Reference ranges for predicting means and SDs of the fetal CS were established. Equations for Z-score calculation were provided, CSDs and CSDd Z-scores were statistically different between normal fetuses and those with PLSVC. Development of CSDs and CSDd Z-score reference ranges in normal fetuses was realized. The CSDs and CSDd Z-scores can provide quantitative evidence in prenatal diagnosis of PLSVC.

A novel systematic approach to the evaluation of the fetal venous system

Sonographic evaluation of the fetal venous system in normal and abnormal conditions has drawn increasing interest in recent years. Whereas the assessment of the fetal heart and the related arteries is standardized using well-defined planes, the fetal venous system is still lacking a systematic approach. In this article we present a novel sonographic algorithm for a systematic examination of the fetal venous system using six planes of transverse and oblique views of the fetal abdomen and chest. These planes, using two-dimensional and color Doppler, enable a targeted demonstration of the typical veins to include the umbilical vein, ductus venosus, portal veins, hepatic veins, inferior vena cava, azygos vein, pulmonary veins, coronary sinus, superior vena cava and brachiocephalic vein. We postulate that integrating such a sequential stepwise algorithm for the evaluation of the venous system into targeted fetal cardiac imaging may improve the detection of isolated and combined anomalies of the fetal systemic and pulmonary veins.

Prenatal diagnosis of abnormal cardinal systemic venous return without other heart defects: a case series

OBJECTIVES

To describe fetal spectrum and echocardiographic characteristics of anomalous systemic venous return (ASVR, cardinal veins) without other structural heart defects (isolated ASVR), evaluate associated extracardiac and genetic anomalies and review neonatal outcome.

METHODS

From 2003 to 2009, 369 consecutive fetuses were diagnosed with cardiac malformation, including 27 cases with an isolated ASVR. The following variables were collected: type of ASVR, extracardiac anomalies, karyotype and short-term outcome.

RESULTS

The most common forms of ASVR were persistent left superior vena cava (SVC) (n = 15) and interrupted inferior vena cava (IVC) (n = 6). The other ASVR types were a persistent left SVC without a right SVC (n = 4), bilateral agenesis of the SVC with cephalic venous drainage toward the IVC through the azygos system (n = 1) and total ASVR to the coronary sinus (n = 1). Genetic disorders were confirmed in five cases, all with a persistent left SVC, with extracardiac anomalies present in four of them. Ten other patients had extracardiac anomalies detected prenatally or postnatally. When available, ASVR diagnosis was confirmed postnatally in all cases.

CONCLUSION

Isolated ASVRs can be accurately diagnosed prenatally and are frequently associated with extracardiac and genetic anomalies. A detailed morphological ultrasound and fetal karyotype should be suggested. Neonatal outcome was mainly related to the associated anomalies.

Hypertrophic cardiomyopathy-like changes in monochorionic twin pregnancies with selective intrauterine growth restriction and intermittent absent/reversed end-diastolic flow in the umbilical artery

OBJECTIVE

To evaluate the prevalence of hypertrophic cardiomyopathy-like (HCL) changes in monochorionic twins with selective intrauterine growth restriction (sIUGR) and intermittent absent/reversed end-diastolic flow (iAREDF), also defined as Type III sIUGR, and the clinical relevance of this condition.

METHODS

A total of 80 pregnancies with sIUGR were studied, 40 with, and 40 without iAREDF. HCL changes were defined as an increased thickness of either left or right ventricular wall (mean > 2 SD) estimated with M-mode ultrasonography. Data were plotted on normal reference values constructed from 75 uncomplicated monochorionic twin pregnancies (150 fetuses) at 22-34 weeks' gestation. Perinatal outcomes in pregnancies with and without HCL changes were compared.

RESULTS

In the group with iAREDF, 8/40 of the larger twins (20%) had HCL changes (five bilaterally, two in the right, and one in the left ventricle) as compared with 1/40 (2.5%) in fetuses without iAREDF (P = 0.03). No differences were observed in the smaller twin (1/40 in both groups). HCL changes were not associated with a significant increment in perinatal mortality as only one large fetus from the group with iAREDF died in utero. In the remaining 10 cases, no differences in the intertwin weight discordance, placental surface discordance, or rate of neonatal neurological damage were observed. However, all 10 presented mildly abnormal neonatal cardiac findings that resolved over time with no apparent short-term impact on cardiac function.

CONCLUSIONS

HCL changes in the larger twin should be regarded as part of the spectrum of findings in Type III monochorionic-sIUGR (presenting iAREDF). This finding does not seem to be associated with an increased rate of short-term neurological or cardiac complications.

Caliber of the coronary sinus in fetuses with cardiac defects with and without left persistent superior vena cava and in growth-restricted fetuses with heart-sparing effect

OBJECTIVE

To assess reference ranges for fetal coronary sinus (CS) diameter and to compare them with values from fetuses showing heart defects with and without left superior vena cava (LSVC) as well as with severe intrauterine growth retardation and heart-sparing effect on color Doppler.

METHODS

The coronary sinus was visualized on two-dimensional ultrasound in a plane slightly caudal to the apical four-chamber view. For the normal range of the size of the CS in relation to gestational age, data was collected from 108/114 (95%) normal fetuses with good visualization between 20 weeks' gestation and term. Abnormal conditions comprised two groups: group 1 consisted of 52 fetuses with heart anomalies, including three subgroups: 11 fetuses with isolated LSVC emptying into the coronary sinus, 12 fetuses with LSVC associated with structural heart defects and 29 fetuses with structural heart defects but without LSVC. Group 2 consisted of 11 fetuses with severe intrauterine growth retardation and dilated coronary arteries as seen by color Doppler ultrasound.

RESULTS

Under normal conditions, there was a significant increase in the CS diameter with advancing gestational age (1.2-2.7 mm). Significant dilatation was found only in the two groups with LSVC (range 2.7-6.5 mm), independent of whether the finding was isolated or associated with cardiac defects.

CONCLUSION

CS visualization and measurements are easily feasible in the human fetus in the apical four-chamber view. Significant dilatation of the CS is a sign of LSVC. The examiner should be aware of this condition as such dilatation is commonly falsely diagnosed as atrial or atrioventricular septal defect.

Evaluation of the fetal coronary circulation

Prenatal ultrasound today allows the detailed study of small caliber vascular beds including the fetal coronary arteries and the coronary sinus. The coronary circulation is unique because of its critical role in myocardial metabolism and function and its ability to adapt in many fetal conditions. The ultrasound examination techniques for the evaluation of the fetal coronary circulation are presented. Evaluation of the coronary arteries is primarily achieved by color flow imaging and pulsed wave Doppler. Conditions such as fetal growth restriction, anemia, ductus arteriosus constriction and bradycardia are associated with evidence of enhanced coronary blood flow. These findings suggest that short-term autoregulation and long-term alterations in myocardial flow reserve are present in the human fetus. At present, examination of coronary sinus blood flow has limited clinical utility, while increases of the coronary sinus diameter or attenuation of coronary sinus dynamics may provide useful markers of abnormalities of central venous drainage. Abnormal vascular connections between the coronary arteries and the ventricular cavities may be observed in outflow tract obstructive cardiac lesions. In these conditions prenatal detection of coronary fistulae may have a potential impact on outcome and therefore counseling and perinatal management.