Early prenatal diagnosis of major congenital heart defects

The myocardial and coronary histopathology and pathogenesis of hypoplastic left heart syndrome

Hypoplastic left heart syndrome has the greatest mortality rate among all CHDs and without palliation is uniformly fatal. Despite noble efforts, the aetiology of this syndrome is unknown and a cure remains elusive. The genetic and anatomic heterogeneity of hypoplastic left heart syndrome supports a rethinking of old hypotheses and warrants further investigation into the histological and vascular variations recognised with this syndrome. In an effort to elucidate the pathogenesis of hypoplastic left heart syndrome, this review will focus on its unique myocardial and coronary pathology as well as evaluate the association of hypoplastic left heart syndrome with the endocardial fibroelastosis reaction.

Feasibility and accuracy of fetal echocardiography using four-dimensional spatiotemporal image correlation technology before 16 weeks' gestation

OBJECTIVES

To evaluate the potential value of early fetal echocardiography (EFE) by means of four-dimensional (4D) spatiotemporal image correlation (STIC) technology for either reassurance of normality or prenatal diagnosis of major congenital heart defects (CHDs).

METHODS

Sixty-nine pregnant women from 11 to 15 weeks' gestation underwent EFE. 4D-STIC volumes were acquired by the transvaginal approach for later review by two different examiners. STIC evaluation was considered complete when the four-chamber view, and the origin and double-crossing of the great arteries were identified correctly. Color Doppler imaging was used to detect either septal shunts or transvalvular regurgitation/aliasing suggesting abnormalities. STIC diagnoses were compared with those of conventional EFE. Reliability was assessed by postnatal examination, or autopsy in cases of termination of pregnancy or perinatal death.

RESULTS

The median gestational age at volume acquisition was 13 + 3 weeks. Eleven (15.9%) cases of CHD were diagnosed. A complete EFE was possible in 64 cases. We were able to provide reassurance of normality in 51 of the 53 confirmed normal hearts, with no false-positive results for major defects, although two minor defects (one ventricular septal defect (VSD) and one persistent left superior vena cava) were falsely suspected. The only false negative was a significant VSD at birth overlooked by both observers. Therefore, the total accuracy of STIC-EFE was 95.3% (61/64), with sensitivity, specificity, and positive and negative predictive values of 90.9%, 96.2%, 83.3% and 98.1%. The accuracy of conventional EFE (98.4%, 63/64) was slightly better than that of STIC, with no false-positive results recorded.

CONCLUSIONS

Offline evaluation of 4D-STIC acquired volumes of the fetal heart in the first and early second trimester of pregnancy is reliable not only for early reassurance of normal cardiac anatomy but also to diagnose most major structural heart defects.

Fetal echocardiography at the time of the nuchal translucency scan

OBJECTIVE

The fetal heart is not studied routinely in the first trimester because of technical and time limitations. Our aim was to assess the feasibility of performing a fetal cardiac study in pregnancies referred for nuchal translucency (NT) screening, using high-frequency linear transabdominal transducers with a specific ultrasound preset.

METHODS

A single trained operator assessed the fetal heart in pregnancies with a fetal crown-rump length (CRL) of 60-84 mm that had been referred for NT screening. A 15- or 6-MHz transabdominal linear transducer with a specific preset suitable mainly for color-flow mapping was used to confirm or refute normal cardiac anatomy rather than to establish a specific diagnosis. Fetuses having an increased risk for congenital heart disease were referred to a tertiary center for a further examination within 1 week. This group consisted of all fetuses with NT > 95(th) centile and those in which a family history or the initial heart scan increased the risk.

RESULTS

A total of 608 fetuses with a median CRL of 65 mm was examined between 2003 and 2005. A cardiac scan was performed successfully in 456 (75%) using a 15-MHz linear transducer alone, and the additional use of a 6-MHz transducer allowed diagnostic images to be obtained in a further 152. Normal cardiac anatomy was assessed confidently within 10 min in 517/608 (85%) pregnancies; in 85 (14%) a longer time was needed and six patients were rescheduled within 2 weeks because of non-diagnostic images at the initial scan. In 571/608 (94%) the risk for congenital heart disease (CHD) was not increased and the heart was considered normal at initial echocardiography; this was confirmed by later scans and at postnatal follow-up. In 37/608 (6%) fetuses the risk for CHD was increased (35 for NT > 95(th) centile and two for family history). In this group normal heart anatomy was described in 34 fetuses and confirmed by subsequent specialist echocardiography. Cardiac defects were suspected in three fetuses (all with increased NT) and confirmed by a fetal cardiologist in each case.

CONCLUSIONS

A trained operator can perform a fetal heart study during the NT screening test using transabdominal high-resolution transducers in an acceptable length of time.

Outcome of fetuses in women with pregestational diabetes mellitus

OBJECTIVE

To investigate the effects of pregestational diabetes on pregnancy outcome.

METHODS

Data of 126 women with pregestational diabetes prospectively collected and controlled in a single tertiary center. HbA(1C) levels at early pregnancy were registered. Adverse pregnancy outcome was defined as spontaneous abortion, congenital defect, stillbirth, or neonatal death.

RESULTS

There were 10 spontaneous abortions (7.9%) and 17 fetuses with congenital anomalies (13.4%), including 8 major malformations (6.3%). Compared with pregnancies with a favorable outcome, a higher HbA(1C) concentration in early pregnancy was observed in pregnancies with adverse perinatal outcome [mean (SD): 6.3 (1.6) vs. 7.2 (1.7), P=0.001]. A positive correlation between increased maternal HbA(1C) levels and the rate of fetal malformations was observed, and the group of women with poor metabolic control (early maternal HbA(1c) concentration >7%) showed a 3 to 5-fold increase in the major malformation rate. Cardiovascular and genitourinary defects accounted for 58.8% of the anomalies, and the ultrasound examinations detected seven of them (41.2%). For major malformations, the detection rate was 50% (4/8). Perinatal mortality rate was 26 per thousand (3/116). There was almost 5-fold increase in the total pregnancy loss rate in the poor control group compared with the group with fair control [22.2% vs. 5.3%, OR (95% CI): 5.1 (1.4-17.1)]. Only 11.9% of mothers used a preconception care program.

CONCLUSIONS

Pregestational diabetes mellitus is a significant risk factor for the developing fetus. Spontaneous abortions and congenital defects are more common when a poor metabolic control is present in early pregnancy. It is most important to improve access to preconception care programs for achieving a good metabolic control in early pregnancy. Ultrasound examinations have a low performance for detecting congenital defects in diabetic pregnancies.

The Team Approach to Pregnancy and Congenital Heart Disease

The successful pediatric management of congenital heart disease has resulted in increasing numbers of these patients in the reproductive age group and increasing clinical challenges for their physicians. These challenges can be met successfully, with improved results for mother and child, through a concerted comprehensive team approach that relies on a thorough understanding of the patient's underlying cardiac pathology and its anticipated interaction with the pregnancy, and ongoing close evaluation and communication with a team of trained and experienced specialist, including (but not limited to) cardiologist, obstetricians, anesthetists, pediatricians, clinical nurse specialists, and clinical geneticists. Such teams are not always available locally and it will be necessary to refer medium- and high-risk patients to a specialized tertiary care center.

Detection rate of early fetal echocardiography and in utero development of congenital heart defects

OBJECTIVE

The purpose of this study was to evaluate the detection rate of early fetal echocardiography and the in utero development of congenital heart defects (CHD).

METHODS

Cases were selected from all singleton pregnancies between 1997 and 2003 in which detailed fetal 2-dimensional and color-coded Doppler echocardiography was performed in our prenatal unit between 11 weeks' and 13 weeks 6 days' gestation; 2165 cases with complete outcome parameters were analyzed.

RESULTS

During this study period, CHD were diagnosed in 46 fetuses. Between 11 and 13 weeks' gestation, 29 CHD were diagnosed (11 weeks, 9 cases; 12 weeks, 8 cases; and 13 weeks, 12 cases); 9 CHD were found in the second trimester and 2 in the third trimester. The in utero detection rate of fetal echocardiography was 86.96% (n = 40). Six additional CHD (13.04%) were detected postnatally. The spectrum of detected CHD changed with advancing gestational age and was different from the postnatal detected heart defects.

CONCLUSIONS

Early fetal echocardiography is feasible and allows the detection of most CHD. Congenital heart defects vary in appearance at different stages of pregnancy and may evolve in utero with advancing gestational age. Therefore, early fetal echocardiography should always be followed by echocardiography at mid gestation.

Early fetal echocardiography: heart biometry and visualization of cardiac structures between 10 and 15 weeks' gestation

OBJECTIVE

The purpose of this prospective cross-sectional study was to compile normative data about biometry of the fetal heart and great vessels between 10 and 15 weeks in 123 normal singleton pregnancies. Additionally, we investigated the different methods and the optimal examination time of early fetal echocardiography.

METHODS

The interrogated parameters included total heart diameter; heart area and circumference; right and left ventricular diameter; diameter, circumference, and area of the thorax; and diameter of the aorta and pulmonary trunk. Visualization of the 4-chamber view, 3-vessel view, origin and crossover of the great arteries, aortic arch, ductus arteriosus, superior and inferior venae cavae, and pulmonary veins was analyzed, and the success rates by transvaginal sonography (TVS) and transabdominal sonography (TAS) were calculated.

RESULTS

Complete evaluation of the fetal heart was impossible at 10 weeks; the total success rate increased from 45% at 11 weeks to 90% between 12 and 14 weeks and 100% at 15 weeks. Between 10 and 13 weeks, TVS was superior to TAS. At 14 weeks, both methods were similar to each other, and at 15 weeks, TAS allowed adequate visualization of all structures. Linear regression analysis showed a significant correlation between the interrogated parameters and gestational age, crown-rump length, and biparietal diameter (P < .05). The ratio of right and left ventricular diameters and the ratio of pulmonary trunk and aortic diameters were constant.

CONCLUSIONS

Early fetal heart evaluation by TVS or TAS or both is reasonable and feasible. Our normative data could be helpful for understanding the normal development of the fetal heart and great arteries and for detection of cardiac defects in early pregnancy.

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.

What prenatal diagnosis should be offered in multiple pregnancy?

The issues surrounding prenatal diagnosis in multiple pregnancy are complex. Accurate determination of chorionicity is vital and an inability to determine this should trigger consideration for referral to a specialist. The choice of screening method for detection of chromosomal abnormality is limited, and existing data demonstrates the advantages of nuchal translucency screening. The possibility of obtaining discordant results and options for management should be discussed in advance. Invasive tests are technically more difficult and associated with a higher risk of procedure-related pregnancy loss than less invasive methods. Repeat invasive testing is required more often in multiple pregnancies than in singleton pregnancies. Selective termination is technically feasible in both mono- and dichorionic pregnancies, although the risks are higher with the former. It is likely to be more acceptable than high-order multifetal reduction performed in the absence of fetal abnormality.

Parental decision-making in congenital heart disease

OBJECTIVE

To explore whether prenatal diagnosis of congenital heart disease is associated with lower levels of parental distress and greater satisfaction with decisions about cardiothoracic surgery when compared to postnatal diagnosis.

METHODOLOGY

A combined quantitative-qualitative design was used. Participants included the parents of 31 neonates (30 mothers and 22 fathers) admitted to the cardiac intensive care unit between 1 November 2001 and 1 May 2002 for repair of congenital cardiac malformations. Participants completed self-report measures of anxiety, optimism, and life events pre-operatively, and semi-structured qualitative interviews assessing satisfaction with decision-making within 1 week of the operation.

RESULTS

At the time of surgery, mothers of neonates receiving the diagnosis prenatally did not differ from mothers of neonates receiving the diagnosis postnatally on measures of anxiety, optimism, and life events. Fathers of neonates receiving the diagnosis prenatally, however, reported more optimism, lower state and trait anxiety, and fewer negative life events than fathers of neonates receiving the diagnosis postnatally. When we analyzed the interviews, we found that, regardless of the timing of the diagnosis, parents felt as though they made a genuine choice for their baby to have surgery.

CONCLUSIONS

In this pilot study, fathers who learned prenatally that their child had a congenital cardiac malformation were less distressed than those who discovered this fact only postnatally. From the parental perspective, nonetheless, distress and urgency do not impair their ability to make decisions about neonatal cardiac surgery.

Cardiac anatomy screening: what is the best time for screening in pregnancy?

PURPOSE OF REVIEW

To consider the ideal gestational age for cardiac evaluation during pregnancy.

RECENT FINDINGS

Screening the heart during routine obstetric ultrasound has become well established and is increasingly successful in the initial detection of major congenital heart disease. When the option of termination of pregnancy is available, the earlier the diagnosis of any major fetal malformation is made, the better for the patient. An important group who have recently been found to be at increased risk of fetal heart malformation are those with increased nuchal translucency measurements, who are identified between 11 and 14 weeks. Thus, screening for fetal anomalies is being attempted much earlier in pregnancy, aided by advances in technology. However, some forms of cardiac malformations do not become evident until the third trimester of pregnancy; as a result, some of the late-developing lesions may go undetected during very early evaluation.

SUMMARY

The ideal timing for screening is a compromise between obtaining adequate images for diagnosis in the majority of routine patients, scanning sufficiently late not to miss late-developing lesions and yet offering diagnosis as early as possible for parents to consider their options, if there are any applicable to their particular diagnosis. For low-risk patients, the best compromise appears to be at around 20 weeks of gestation. For patients at increased risk of congenital heart disease, such as those found to have substantially increased nuchal translucency or those with a family history of the disease, an initial scan to exclude major malformations should be performed by the fetal cardiology expert at 12-14 weeks, with follow-up at around 20 weeks to exclude more minor defects and those lesions which may become evident later.

Screening fetal echocardiography by telemedicine: efficacy and community acceptance

OBJECTIVE

Our aim was to assess whether tertiary level screening fetal echocardiography can be extended to primary care facilities with telemedicine assistance.

METHODS

Assessment of image quality and the adequacy of fetal echocardiograms recorded after random transmission at 128, 384, or 768 kbits/s was performed. Live fetal echocardiograms were transmitted at 384 kbits/s (3 integrated services digital network lines) from the remote primary care center. Patient satisfaction was assessed by surveys obtained after office-based and telemedicine consultations.

RESULTS

A total of 58 recorded normal studies had similar image quality and adequacy on transmission at 384 and 768 kbits/s (P =.08 and.49, respectively) and were significantly better than 128 kbits/s (P <.01). During live screening transmitted at 384 kbits/s from the primary care center, 3 of 34 fetuses were diagnosed with heart disease. Surveys from patients with direct physician contact and by telemedicine showed a high satisfaction with telemedicine-assisted screening and counseling.

CONCLUSION

Adequate screening for fetal heart disease is technically feasible at or above data transmission rates of 384 kbits/s. Community acceptance for telemedicine-assisted screening and counseling is not adversely affected by a lack of direct personal contact with the specialist.

Cardiac defects in chromosomally normal fetuses with increased nuchal translucency at 10-14 weeks of gestation

OBJECTIVE

To examine the prevalence, distribution and spectrum of cardiac defects in chromosomally normal fetuses with increased nuchal translucency thickness.

PATIENTS AND METHODS

During a 4-year period, targeted fetal echocardiography was used in 353 chromosomally normal fetuses with increased nuchal translucency thickness at 10-14 weeks' gestation. The cardiac scan was performed at 18-22 weeks. In the last 138 cases enrolled, an additional scan at 12-16 weeks was carried out. The follow-up included the findings at necropsy or in the pediatric examination. A complete follow-up was achieved in 97%.

RESULTS

Cardiac defects were present in 32 (9.1%) cases, increasing from 5.3% in those with a nuchal translucency thickness of > or = 95th centile (3.9 mm) to 24% when thickness > or = 6 mm (p < 0.001). In 31 cases (97%), the cardiac defect was diagnosed antenatally; in 24 cases (77%) this diagnosis was confirmed later. In the remaining seven cases, the autopsy examination was not available. A wide range of cardiac defects was observed, with the most common being atrioventricular septal defect and tricuspid atresia.

CONCLUSIONS

Euploid fetuses with increased nuchal translucency thickness have a significantly increased risk of cardiac defects. This is a marker of different types of heart anomalies and constitutes an additional indication for targeted fetal echocardiography. Most of the cardiac defects can be detected by fetal echocardiography.

Three cross-sectional planes for fetal color Doppler echocardiography

Routine use of color Doppler during every fetal cardiac examination remains controversial. Many examiners still believe that color should be reserved for cases of suspected congenital heart defect (CHD). In our opinion, color Doppler should be applied in every cardiac scan due to the increase in speed and accuracy that it allows. The purpose of this review is to first explain how color Doppler presets can be optimized and, second, to propose the use of three cross-sectional planes to simplify color Doppler fetal echocardiography: the four-chamber (4CV), five-chamber (5CV) and three-vessel (3VV) views. A practical approach to the detection of CHD with these planes is presented, with typical findings and possible abnormalities evident during systole and diastole. The diastolic pattern on the 4CV is characterized by two equal color stripes. Connection ('H'-sign) or size inequality of the two stripes, or a unilateral color stripe, are important abnormal findings. In systole valve regurgitation should be excluded. In the 5CV, turbulent flow, ventricular septal defect or an overriding aorta ('Y'-sign) can be detected. In the 3VV the aorta and pulmonary trunk should be of nearly equal size and demonstrate antegrade flow. Abnormal findings encountered include absence of one vessel, discrepant size of the vessels, retrograde flow in one of the vessels, or the 'U'-sign, where the trachea is enclosed between both vessels, suggesting right-sided aortic arch. In summary, we propose that color Doppler examination utilizing these three planes alone is sufficient to obtain adequate information for the detection of most common CHD.

Early prenatal diagnosis of major cardiac anomalies in a high-risk population

OBJECTIVE

To examine the accuracy of early fetal echocardiography performed in a high-risk population combining transvaginal and transabdominal routes.

METHODS

A series of 330 high-risk pregnancies were screened by transvaginal and transabdominal scan at 12-17 weeks' gestation in a prospective multicentre trial in Spain between September 1999 and May 2001. A total of 334 fetal heart examinations were performed, including four twin pregnancies. Maternal age ranged from 17 to 46 years (mean 33 years with 36% of women over 34 years). The median gestational age at scan was 14.2 weeks (range 12-17 weeks). For each fetus, visualization of the four-chamber view, the origin of the great arteries, aortic and ductal arches and systemic venous return was attempted in a segmental approach. B-mode and colour/pulsed Doppler flow imaging were used in all cases. The duration of complete heart examination was less than 30 minutes. The examinations were performed by three experienced operators. Reliability was assessed by conventional transabdominal echocardiography at 20-22 weeks, by postnatal follow-up in the first three months of life, and/or by autopsy in cases of termination of pregnancy.

RESULTS

The rate of successful visualization of the fetal heart was 94.6% (316/334). In 48 out of 334 (14.4%) fetuses the final diagnosis was abnormal. In 38 out of 48 (79.2%) cases with heart defects the diagnosis was suspected at early echocardiography. In the group with congenital heart defects, 27 cases had an abnormal karyotype (56.3%) and 31 cases showed extracardiac anomalies (64.6%). There were 10 false-negative cases at early scan. There were no false-positive diagnoses.

CONCLUSIONS

This experience stresses the usefulness of early fetal echocardiography when performed by expert operators on fetuses specifically at risk for cardiac disease. The high rate of successful visualization of the fetal heart provides a reliable diagnosis of major cardiac defects at this early stage of pregnancy.

Cardiac disease in pregnancy

Congenital heart disease in pregnancy is increasingly common because of the advances in surgery and medical therapy which have taken place over the last 30 years, which means that more affected women are surviving into the reproductive age. Antenatal counselling needs to be tailored to the specific lesion, with pulmonary hypertension and cyanotic disease presenting a risk of maternal mortality of up to 50%. The use of anticoagulants in women with artificial valves presents a particular challenge, heparin being safer for the baby and warfarin for the mother. Peripartum cardiomyopathy and Marfan's syndrome may be less dangerous than once thought. The risk of congenital heart disease in the fetus is increased, from twice to 20-fold, depending on the nature of the mother's lesion. Care throughout pregnancy and in the puerperium should be multidisciplinary and include cardiologists, obstetricians and midwives with experience of such cases, preferably in a tertiary centre.