Structural cardiac anomalies

Prenatal ultrasound screening of congenital heart disease in the general population: general concepts, guidelines, differential diagnoses

Congenital heart diseases (CHDs) carry a high prevalence rate in the general population (0.8%-1%). Most fetal CHDs occur in patients without any risk factors. The prenatal recognition of CHD has major impacts on the pregnancy and its outcome. The aforementioned data justify prenatal ultrasound (US) screening of CHD in the general low-risk population. As demonstrated in the literature, the application of an extended basic US cardiac examination improves the detection of CHD, in particular the conotruncal anomalies. The stepwise method suggested for fetal heart US screening during the mid-second trimester sonogram is based on 4 routine axial views of heart and great vessels: (1) a transverse view of the superior abdomen, (2) a 4-chamber view, (3) a 3-vessel view, and (4) a transverse view of the aortic arch. This protocol can be obtained rapidly because these scans are easy to perform. Despite the fact that the sequential segmental approach universally used in the postnatal diagnosis of CHD is not specifically addressed here, the detected anomalies can be categorized according to these views, and a short differential diagnosis proposed. Abnormal cardiac and/or vascular landmarks shown on these key scans should lead to a referral in the fetal cardiac center for a more precise evaluation, as well as for counseling.

"At fingers' ends": risk factors and perinatal outcome of pregnancies complicated by digital malformations

OBJECTIVE

To identify the incidence, risk factors, and perinatal outcome of newborns with congenital finger or toe (digital) anomalies.

METHOD

A retrospective study including all neonates born at a tertiary medical center during 2001-2006 with congenital digital anomalies was conducted. The comparison group consisted of newborns without such anomalies born during the same period.

RESULTS

Of 115,876 newborns delivered during the study period, 360 (31 per 10,000) were diagnosed with digital anomalies. Polydactyly was the most common diagnosis (n = 263; 73% of digital anomalies). Associated anomalies in these patients were congenital heart malformations (n = 93; 25.8% of the newborns with congenital digital anomalies), central nervous system anomalies (n = 17; 4.7%), and musculoskeletal anomalies (n = 13; 3.6%). Newborns with congenital digital anomalies were more likely to be males (62.2 vs. 37.8%; P < 0.001), and of a Bedouin Arab descent compared to Jewish ethnicity (61.4 vs. 38.6%; P = 0.004). Significantly higher rates of severe pre-eclampsia, recurrent abortions, transverse lie, and low birth-weight (<2,500 g) infants were found among newborns with digital anomalies.

CONCLUSIONS

The incidence of digital anomalies can vary according to the population characteristics. It may be associated with other skeletal and non-skeletal malformations as well as with certain adverse obstetrical and perinatal outcomes. If a fetal digit anomaly is suspected, a detailed assessment of fetal anatomy is mandatory to exclude other malformations.

Reducing the cost of detection of congenital heart disease in fetuses of women with pregestational diabetes mellitus

OBJECTIVE

To provide a cost minimization analysis to support a paradigm shift in the use of comprehensive ultrasound and echocardiography in the prenatal diagnosis of congenital heart disease (CHD) in fetuses of women with diabetes mellitus (DM).

METHODS

In this retrospective cohort study, the diabetic clinic service database of the University of California San Diego was searched from January 2001 to June 2004 for pregnant women with Type I or II DM and HbA1c >6.3%. Subjects underwent comprehensive ultrasound examination (with four-chamber views and outflow tracts) and fetal echocardiography according to a standard protocol. Newborns were examined for cardiac defects and underwent postnatal echocardiography as indicated. The cost of screening was evaluated.

RESULTS

Of 115 neonates and two terminations of pregnancy there were 20 (17%) cases of CHD. Six of these CHD were major and all six were detected prenatally by both ultrasound and echocardiography. Three additional clinically insignificant cases of CHD were identified by fetal echocardiography. Eleven cases of CHD were identified by postnatal echocardiography only, all of which were clinically insignificant lesions. The prenatal detection rate of major CHD was 100% (6/6) for both ultrasound and echocardiography. The sensitivites of ultrasound (30% (95% CI, 13-54%)) and echocardiography (45% (95% CI, 24-68%)) were similar (P = 0.32). A cost minimization analysis was done using the published Medicaid (California) system's relative value unit and conversion factors. Accordingly, our current protocol costs $6503.43 per case of major CHD detected. If echocardiography had been performed only as indicated and postnatal echocardiography had been performed on all neonates, the cost would have been $7056.83 per case of major CHD detected. Alternatively, combined targeted ultrasound with indicated prenatal and postnatal echocardiography would have been associated with a cost of $4996.05 per case of major CHD detected.

CONCLUSION

Detection of major CHD was excellent with both comprehensive prenatal ultrasound and echocardiography. Echocardiography added little to the prenatal diagnosis of CHD if the comprehensive ultrasound examination was normal. The highest cost-benefit ratio and most efficacious protocol for screening based on our data would be comprehensive ultrasound with prenatal and postnatal echocardiography only as indicated. Further prospective studies are warranted.

Prenatal sonographic diagnosis of congenital heart disease and intrauterine growth restriction: a case-control study

PURPOSE

To determine the prevalence of intrauterine growth restriction (IUGR) in cases of congenital heart disease (CHD) and to evaluate whether the prenatal diagnosis of isolated CHD was a significant risk factor for IUGR.

METHODS

We conducted a retrospective case-control study of prenatally detected CHD with delivery at >/=20 weeks' gestation between January 1, 1998, and December 31, 2001. Four groups were analyzed: (1) all cases with CHD, (2) after exclusion of abnormal karyotype, (3) after exclusion of abnormal karyotype and prenatally diagnosed extracardiac anomaly, and (4) after exclusion of abnormal karyotype and prenatally and postnatally diagnosed extracardiac anomaly. The prevalence of IUGR was determined in each of the 4 study groups and was compared with controls.

RESULTS

There were 13,395 deliveries at >/=20 weeks' gestation. Of the 180 cases of CHD, 22.8% were associated with IUGR compared with 11.6% of controls (p < 0.01). In contrast, there was no statistically significant difference in the prevalence of IUGR in the 140 cases of isolated CHD compared with controls (12.9% versus 10.0%).

CONCLUSION

The prenatal detection of isolated CHD does not seem to be associated with IUGR.

Cardiovascular phenotyping of fetal mice by noninvasive high-frequency ultrasound facilitates recovery of ENU-induced mutations causing congenital cardiac and extracardiac defects

As part of a large-scale noninvasive fetal ultrasound screen to recover ethylnitrosourea (ENU)-induced mutations causing congenital heart defects in mice, we established a high-throughput ultrasound scanning strategy for interrogating fetal mice in utero utilizing three orthogonal imaging planes defined by the fetus’ vertebral column and body axes, structures readily seen by ultrasound. This contrasts with the difficulty of acquiring clinical ultrasound imaging planes which are defined by the fetal heart. By use of the three orthogonal imaging planes for two-dimensional (2D) imaging together with color flow, spectral Doppler, and M-mode imaging, all of the major elements of the heart can be evaluated. In this manner, 10,091 ENU-mutagenized mouse fetuses were ultrasound scanned between embryonic days 12.5 and 19.5, with 324 fetuses found to die prenatally and 425 exhibiting cardiovascular defects. Further analysis by necropsy and histology showed heart defects that included conotruncal anomalies, obstructive lesions, and shunt lesions as well as other complex heart diseases. Ultrasound imaging also identified craniofacial/head defects and body wall closure defects, which necropsy revealed as encephalocele, holoprosencephaly, omphalocele, or gastroschisis. Genome scanning mapped one ENU-induced mutation associated with persistence truncus arteriosus and holoprosencephaly to mouse chromosome 2, while another mutation associated with cardiac defects and omphalocele was mapped to mouse chromosome 17. These studies show the efficacy of this novel ultrasound scanning strategy for noninvasive ultrasound phenotyping to facilitate the recovery of ENU-induced mutations causing congenital heart defects and other extracardiac anomalies.

Treatment of acute myeloid leukemia during the second and third trimesters of pregnancy

Fortunately, the occurrence of acute myeloid leukemia (AML) during pregnancy is rare. We report a case of successful fetal outcome with standard induction and consolidation treatment in the second and third trimesters, respectively. A 37-year-old woman in her second trimester (21 wks) of pregnancy was found to have acute myeloid leukemia. She elected to maintain the pregnancy and underwent induction with cytarabine and idarubicin. Her hospital course was complicated by Pseudomonas vesicularis and gram-positive bacilli (not Bacillus anthracis) septicemia, but she obtained complete remission. After discharge, a fetal echocardiogram at 26 weeks revealed a mildly dilated right ventricle with mild systolic dysfunction, and the left ventricle appeared smaller than normal with mild systolic dysfunction. The patient then received consolidation therapy with high-dose cytarabine. On day 14 of consolidation, filgrastim 16 mug/kg was added to improve stem cell mobilization. A total of 19.8x10(6) CD34+ cells/kg were collected with a single apheresis session. At 37 weeks, she delivered a viable female infant weighing 3 lbs 12 oz. Fetal abnormalities included acrocyanosis, shallow sacral dimple, short digits and limbs, and prominent frontal skull with mild macrognathia. A postnatal echocardiogram revealed a moderate-sized membranous ventricular septal defect. The ventricular septal defect proved significant and required surgical repair at 5 months. Approximately 4 weeks after delivery, the mother underwent autologous peripheral stem cell transplantation. Unfortunately, 100 days after transplantation, she had a relapse of AML. After a brief remission from a second induction, the patient died.

Prenatal diagnosis of congenital cardiac anomalies: a practical approach using two basic views

Structural cardiac anomalies are estimated to occur in 8 of every 1,000 live births. Cardiovascular anomalies are frequently associated with other congenital anomalies because the heart is among the last organs to develop completely in the embryo. The guidelines for routine prenatal evaluation of both the American College of Radiology and the American Institute of Ultrasound in Medicine require evaluation of the fetal heart. The ultrasonographic (US) view that is most commonly used is the four-chamber view, which allows assessment of abnormalities involving the atria and the ventricles. However, this view is not adequate for demonstrating the outflow tracts of the aorta and pulmonary artery. A base view that demonstrates the crossing of the great vessels can be obtained just superior to the four-chamber view. Addition of the base view to routine US evaluation with the four-chamber view increases not only the sensitivity for detection of cardiac anomalies but also the accuracy of diagnosis.